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Every calculator runs entirely in your browser — instant results, no signup, nothing sent to a server. ### Business & Marketing #### Aldosterone-to-Renin Ratio (ARR) Calculator URL: https://geratools.com/aldosterone-renin-ratio Compute the aldosterone-to-renin ratio (ARR) from plasma aldosterone and renin, with unit conversion between pmol/L, ng/dL, direct renin concentration, and plasma renin activity, against the Endocrine Society positive-screen cut-off. How to use: 1. Enter aldosterone: Type the plasma aldosterone and select pmol/L or ng/dL. The tool converts ng/dL to pmol/L using a factor of 27.7. 2. Enter renin: Enter the renin value and choose whether it is a direct renin concentration in mU/L or plasma renin activity in ng/mL/h, which the tool converts. 3. Read the ratio and screen: The tool returns the ARR in pmol/L per mU/L and flags a positive screen when the ratio and aldosterone both cross their thresholds. FAQ: Q: What is a positive ARR? A: A widely used Endocrine Society cut-off is an ARR above 30 pmol/L per mU/L, combined with an aldosterone that is meaningfully elevated, typically at least about 270 pmol/L or 10 ng/dL. Both conditions reduce false positives from suppressed renin alone. Q: What is the difference between PRA and direct renin? A: Plasma renin activity (PRA) measures the rate of angiotensin generation in ng/mL/h, while direct renin concentration (DRC) measures renin mass in mU/L. The tool converts PRA to DRC using roughly 8.2 mU/L per ng/mL/h so the ratio uses consistent units. Q: Why must aldosterone also be elevated? A: When renin is strongly suppressed for other reasons, the ratio can rise even with a normal or low aldosterone. Requiring an aldosterone above a minimum threshold alongside a high ratio makes the screen more specific for true primary aldosteronism. Q: What can distort the ARR? A: Posture, time of sampling, potassium level, and many drugs affect the result. Beta-blockers raise the ratio, while ACE inhibitors, ARBs, diuretics, and mineralocorticoid receptor antagonists lower it. Sampling conditions should be standardised before interpreting the ratio. Q: Does a positive screen confirm the diagnosis? A: No. A positive ARR is a screening result that should be followed by a confirmatory suppression test such as saline infusion or oral salt loading, then subtype testing. Always interpret against your own laboratory's assay and reference. #### Bone Marrow Blast Percentage Calculator URL: https://geratools.com/bone-marrow-blast-percentage Convert raw blast, erythroid, and other nucleated cell counts from a 200- or 500-cell bone marrow differential into blast percentage of all nucleated cells and of non-erythroid cells, against the WHO 20% AML threshold. How to use: 1. Count and enter blasts: From your 200- or 500-cell differential, enter the number of blast cells counted. 2. Enter erythroid and other counts: Enter the nucleated erythroid (red precursor) cells and all other nucleated cells separately, because erythroid cells change the denominator. 3. Read both percentages: The tool reports blasts as a percentage of all nucleated cells and of non-erythroid cells, and flags whether the WHO 20% AML threshold is met. FAQ: Q: What is the WHO blast threshold for AML? A: The WHO classification defines acute myeloid leukaemia as 20% or more blasts of all nucleated cells in the bone marrow or blood. Below 20% the picture usually falls into MDS or another category, subject to the clinical and genetic context. Q: Why are erythroid cells counted separately? A: When erythroid precursors make up 50% or more of the marrow, blasts are also expressed as a percentage of non-erythroid cells, an older FAB rule still used in some schemes. Separating erythroid from other cells lets the tool compute that non-erythroid denominator. Q: How is the non-erythroid percentage calculated? A: Non-erythroid cells equal the total nucleated count minus the erythroid count. Blast percentage of non-erythroid cells is blasts divided by that non-erythroid total, times 100. The tool only shows it when it is meaningful. Q: How many cells should I count? A: A 500-cell differential is standard for marrow and gives a more stable percentage than a 200-cell count, especially near the 20% cut-off. The tool works with any totals you enter; larger counts reduce sampling error. Q: Does meeting 20% always mean AML? A: No. Some defining genetic abnormalities such as t(8;21), inv(16), or PML-RARA establish AML regardless of blast count, and the blast count must be interpreted with morphology, flow cytometry, and genetics. This tool computes percentages only. #### Bow Arrow Kinetic Energy & FOC Calculator URL: https://geratools.com/bow-arrow-kinetic-energy Free bow arrow kinetic energy and FOC calculator. Enter component weights, arrow speed, length, and balance point to get total weight, kinetic energy in ft-lbs, momentum, grains per pound, and front-of-center percentage. For compound and traditional bowhunters. How to use: 1. Enter component weights: Type the grain weight of the point, insert, shaft, fletching, and nock so the tool can total your complete arrow weight. 2. Add speed and geometry: Enter the arrow speed in fps, the full arrow length, and the measured balance point, both measured from the throat of the nock. 3. Read KE, momentum and FOC: The calculator returns total weight, kinetic energy, momentum, grains per pound, and front-of-center percentage with a tuning label. FAQ: Q: What is FOC and how is it calculated? A: FOC, or front of center, is how far forward the arrow's balance point sits as a percentage of its length. The formula is 100 times the balance point minus half the length, divided by length, with both measurements taken from the throat of the nock. Higher FOC improves stability and penetration. Q: What FOC should I aim for? A: Target and field archers typically run 7 to 12 percent. Hunters often prefer 10 to 19 percent for better penetration and forgiveness. Extreme or Ashby setups exceed 19 percent for maximum penetration on large game, at the cost of a more arcing trajectory. Q: How is arrow kinetic energy calculated? A: Kinetic energy in ft-lbs equals total arrow weight in grains times speed in fps squared, divided by 450,240. Momentum in slug-fps equals weight times speed divided by 225,218. Momentum often predicts penetration better than energy for heavy arrows. Q: What is grains per pound and why does it matter? A: Grains per pound (gpp) is total arrow weight divided by draw weight. Shooting below about 5 gpp can damage a compound bow because too little of the stored energy is absorbed by the arrow. The tool flags any setup under 5 gpp as unsafe. Q: Where do I measure the balance point from? A: Both the balance point and the arrow length are measured from the throat of the nock (where the string sits) toward the point. Balance the finished arrow on a straight edge to find its center of gravity, then measure that distance. #### D&D Ability Score Optimizer URL: https://geratools.com/dnd-ability-score-standard-array Enter your rolled or standard array values and pick a class to get the optimal ability placement, with modifiers and saving-throw proficiencies highlighted. For new D&D 5e players assigning stats during character creation. How to use: 1. Enter your six values: Type your rolled stats or use the standard array button to load 15, 14, 13, 12, 10, 8. 2. Choose your class: Select your class so the tool knows which abilities to prioritize and which saving throws you are proficient in. 3. Read the optimal placement: The tool assigns your highest values to your class's most important abilities and shows modifiers plus your two save proficiencies. FAQ: Q: What is the D&D 5e standard array? A: The standard array is a fixed set of six ability scores, 15, 14, 13, 12, 10, and 8, that you assign to your six abilities. It is an alternative to point buy and rolling that guarantees a balanced, fair spread for every character. Q: How does the optimizer place my scores? A: It sorts your six values from highest to lowest and assigns them to your class's ability priority order, so your top score lands in the class's key ability. For a Wizard that means Intelligence first, while a Fighter gets Strength first. Q: What are saving-throw proficiencies? A: Each class grants proficiency in two saving throws, adding your proficiency bonus to those saves. The tool highlights them so you can see whether your strong stats line up with your proficient saves, which makes a more resilient character. Q: Can I use my own rolled stats instead? A: Yes. Enter any six values between 1 and 20 separated by commas. The optimizer works the same way, sorting and placing them by class priority, so it is just as useful for rolled characters as for the standard array. Q: Is the suggested placement always best? A: It is an excellent default that maximizes your primary ability and protects key saves, but flavor, multiclassing plans, and racial bonuses can shift things. Treat the output as a strong starting point you can adjust to your concept. #### D&D Carrying Capacity Calculator URL: https://geratools.com/dnd-carrying-capacity Calculate D&D 5e carrying capacity, push/drag/lift limits, and variant encumbrance thresholds from a Strength score and creature size. Uses the official Player's Handbook rules so you can manage inventory weight in seconds. How to use: 1. Enter your Strength score: Type your character's Strength ability score (1-30). Carrying capacity scales directly with it. 2. Choose creature size: Pick your size. Capacity doubles for Large, quadruples for Huge, and halves for Tiny creatures. 3. Read your limits: See your carrying capacity, push/drag/lift maximum, and the optional encumbered and heavily encumbered thresholds. FAQ: Q: What is the carrying capacity formula in D&D 5e? A: Carrying capacity in pounds equals your Strength score multiplied by 15. A character with Strength 15 can carry 225 lb before any variant rules apply. Q: How much can my character push, drag, or lift? A: You can push, drag, or lift up to your Strength score times 30 pounds — double your normal carrying capacity. Moving that much weight, however, halves your speed. Q: How does size change the numbers? A: Multiply the result by your size factor: Tiny x0.5, Small and Medium x1, Large x2, Huge x4, and Gargantuan x8. A Large creature with Strength 19 carries 570 lb. Q: What are encumbered and heavily encumbered? A: These come from the optional variant encumbrance rule. You are encumbered above Strength x5 pounds (speed drops 10 ft) and heavily encumbered above Strength x10 pounds (speed drops 20 ft plus disadvantage on Strength, Dexterity, and Constitution checks, attacks, and saves). Q: Do most tables use the variant rule? A: No. Standard 5e only tracks the single carrying-capacity number and ignores weight until you hit it. The encumbered thresholds are an optional rule, so check with your DM before applying them. #### Fuse vs. Circuit Breaker Comparison Tool URL: https://geratools.com/electrical-fuse-vs-breaker-comparison Compare simplified time-current clearing behavior of Class CC, J, and RK5 current-limiting fuses against a molded-case circuit breaker at the same ampere rating across a range of fault-current multiples. A teaching aid for overcurrent device selection and coordination. Runs in your browser. How to use: 1. Enter the device rating: Type the ampere rating shared by the fuse and breaker you want to compare. 2. Choose a fuse class: Pick Class CC, J, or RK5 to set the fuse's relative speed and current-limiting threshold. 3. Read the clearing times: Set the fault current as a multiple of rated and read the estimated clearing time for each device across the table. FAQ: Q: What is a current-limiting fuse? A: A current-limiting fuse interrupts a high fault within the first half-cycle, before the current reaches its prospective peak. By clearing that fast it limits the let-through energy and peak current the downstream equipment ever sees, which protects busbars and conductors during high available-fault conditions. Q: How is a fuse different from a breaker on a high fault? A: On a high fault the fuse melts and clears in under half a cycle, while a thermal-magnetic breaker trips on its instantaneous magnetic element in roughly one to two cycles. The fuse is therefore faster on severe faults and limits energy, but a tripped breaker can be reset whereas a blown fuse must be replaced. Q: What do Class CC, J, and RK5 mean? A: These are UL fuse classes with different sizes, interrupting ratings, and time-delay characteristics. Class CC and J are fast-acting and physically small with high interrupting ratings; Class RK5 is a time-delay fuse that tolerates motor inrush. The tool reflects their relative speeds, not exact catalog curves. Q: Why does the breaker trip instantly above about ten times rated? A: A molded-case breaker has a thermal element for overloads and a magnetic element for short circuits. The magnetic element has an instantaneous pickup, often eight to thirteen times rated current, above which the breaker trips in one to two cycles regardless of the thermal curve. This tool models that pickup at ten times rated. Q: Can I use this for a real coordination study? A: No. These are simplified representative curves for teaching and quick intuition. A real selective-coordination or arc-flash study must use the manufacturer's published time-current curves, the actual available fault current, and let-through energy tables, ideally in coordination software. #### Grounding & Bonding Checklist Generator (NEC 250) URL: https://geratools.com/electrical-grounding-bonding-checklist Builds a printable NEC Article 250 grounding and bonding checklist from service amperage, panel type, electrode types and the presence of metal water piping and structural steel, sizing the grounding electrode conductor and equipment bonding jumper from Tables 250.66 and 250.102. Runs in your browser. How to use: 1. Enter the service details: Type the service ampacity and the size of the largest ungrounded service conductor, then select whether this is a main service panel or a subpanel. 2. Mark the electrodes present: Tick the grounding electrodes at the site such as ground rods, a concrete-encased electrode, metal water pipe and structural steel. 3. Read the checklist: The tool sizes the grounding electrode conductor and bonding jumpers from NEC tables and outputs a printable list of required Article 250 connections. FAQ: Q: How is the grounding electrode conductor sized? A: The grounding electrode conductor is sized from NEC Table 250.66 based on the largest ungrounded service-entrance conductor. For example a 2/0 copper service conductor requires a 4 AWG copper grounding electrode conductor. A connection to a ground rod only never needs to be larger than 6 AWG copper. Q: Why is a concrete-encased electrode required when available? A: NEC 250.50 requires that all grounding electrodes present at a building be bonded together. A concrete-encased electrode, sometimes called a Ufer ground, is one of the most effective electrodes, and if it exists in the foundation footing it must be used and bonded into the system. Q: What is the difference between the main service and a subpanel? A: At the main service the grounded neutral and the equipment ground are bonded together through the main bonding jumper. At a subpanel they must be kept separate, with an isolated neutral bus and a separate equipment ground bus, and the feeder must include an equipment grounding conductor. The checklist changes accordingly. Q: Does metal water piping need bonding? A: Yes. NEC 250.104 requires interior metal water piping likely to become energized to be bonded to the service equipment, the grounded conductor or the grounding electrode system, sized per Table 250.66. If the metal water pipe is also in contact with earth for at least ten feet it additionally serves as a grounding electrode. Q: Do two ground rods always need each other? A: A single made electrode such as a ground rod that does not have a resistance to earth of 25 ohms or less must be supplemented by a second electrode per NEC 250.53(A)(2). In practice most installers simply drive two rods at least six feet apart by default to satisfy this without testing resistance. #### Electrical Safety Clearance Distance Calculator URL: https://geratools.com/electrical-safety-clearance-calculator Enter a nominal AC system voltage from 50 V to 800 kV and get the limited approach and restricted approach shock boundaries from NFPA 70E Table 130.4(D)(a), with guidance for qualified versus unqualified workers near energized equipment. Runs in your browser. How to use: 1. Enter the system voltage: Type the nominal phase-to-phase AC voltage in volts, for example 480 for a 480 V system or 15000 for 15 kV. 2. Choose the worker classification: Select qualified or unqualified so the tool gives the correct guidance on which boundaries each worker may cross. 3. Read the approach boundaries: The tool returns the limited approach boundary for movable and fixed conductors and the restricted approach boundary, all in feet and inches. FAQ: Q: What is the difference between the limited and restricted approach boundaries? A: The limited approach boundary is the closest an unqualified person may come without an escort. The restricted approach boundary is the closest a qualified person may come, and only with proper insulated PPE, tools, and a documented plan because of the increased risk of inadvertent contact. Q: Why is there no prohibited approach boundary? A: NFPA 70E removed the prohibited approach boundary after the 2015 edition because it added complexity without improving safety. The restricted approach boundary is now the innermost shock-protection boundary, and direct contact with energized parts requires rated protection regardless. Q: Does this give the arc flash boundary too? A: No. The arc flash boundary is a separate energy-based calculation tied to the incident energy reaching 1.2 cal/cm squared at the worker, which depends on available fault current and clearing time. This tool covers only the shock approach distances from Table 130.4(D)(a). Q: Why are there two limited approach distances? A: An exposed movable conductor, such as an overhead line that can swing, requires a larger limited approach distance than a fixed circuit part that cannot move toward the worker. The table lists both so you can apply the correct one for the hazard present. Q: Can an unqualified worker ever cross the limited boundary? A: Only when continuously escorted by a qualified person and equipped with appropriate PPE. Otherwise the limited approach boundary is the hard line an unqualified worker must stay outside of around energized equipment. #### Electrophoresis DNA Ladder Band Size Estimator URL: https://geratools.com/electrophoresis-band-size-estimator Estimate DNA fragment sizes from a gel by entering ladder band sizes and migration distances, then unknown band distances. Uses semi-log linear interpolation to size PCR products and restriction fragments. For molecular biologists. Runs in your browser. How to use: 1. Enter the ladder bands: For each visible marker band, type its known size in base pairs and how far it migrated from the well, measured in millimetres or pixels. 2. Enter your unknown bands: Add the migration distance of each sample band you want to size, using the same distance scale as the ladder. 3. Read the estimated sizes: The tool fits a semi-log line through the bracketing ladder bands and interpolates each unknown band's size. FAQ: Q: Why is DNA migration semi-logarithmic? A: In agarose gel electrophoresis the distance a fragment travels is roughly proportional to the logarithm of its size, not its size directly. Small fragments move much faster, so plotting log size against distance gives an approximately straight line that can be interpolated. Q: How does the interpolation work? A: The tool finds the two ladder bands that bracket each unknown by migration distance, then draws a straight line between their log-sized values and the matching distances. It reads the unknown distance off that line and converts back from log to base pairs. Q: What distance unit should I use? A: Any consistent unit works: millimetres measured with a ruler, or pixels measured in image software. The estimate depends only on the ratios between distances, so the choice of unit cancels out as long as the ladder and samples share it. Q: Why must my band fall within the ladder range? A: Interpolation is only reliable between known points. A band that migrates further or less than every ladder band would require extrapolation off the end of the fitted line, where the semi-log relationship breaks down, so the tool flags it rather than guessing. Q: How accurate is the estimate? A: On a well-run gel with closely spaced ladder bands, semi-log interpolation is typically within a few percent. Accuracy falls near the gel limits, with very large or very small fragments, and when ladder bands are far apart, so treat sizes as estimates. #### FM Synthesis Carrier:Modulator Ratio Calculator URL: https://geratools.com/fm-synthesis-ratio Explore carrier-to-modulator frequency ratios for FM synthesis. Enter a C:M ratio to see whether it produces a harmonic (integer-ratio) or inharmonic (metallic) timbre, the resulting sideband frequencies, and the perceived fundamental. Includes the classic DX7 ratio reference table. How to use: 1. Enter the C:M ratio: Type the carrier and modulator numbers, for example 1 and 1, or 1 and 1.41. The ratio drives the whole spectrum. 2. Read the classification: The tool reports whether the ratio is harmonic (whole-number) or inharmonic, and gives the perceived fundamental. 3. Inspect the sidebands: It lists the first several sideband frequencies generated around the carrier so you can predict the timbre. FAQ: Q: What is the carrier-to-modulator ratio in FM synthesis? A: In two-operator FM the carrier is the oscillator you hear and the modulator bends its pitch rapidly. The ratio of their frequencies, written C:M, determines the harmonic content. A simple integer ratio like 1:1 or 2:1 gives a pitched, musical tone. Q: What makes a timbre harmonic versus inharmonic? A: When C:M reduces to a ratio of small whole numbers, the sidebands fall on a harmonic series and the ear hears a clear pitch like a brass or organ sound. Non-integer ratios such as 1:1.41 scatter the sidebands off the harmonic series, producing bell, gong, and metallic timbres with no single clear pitch. Q: How are FM sidebands generated? A: Frequency modulation creates pairs of sidebands at the carrier frequency plus and minus whole-number multiples of the modulator frequency: C, C plus or minus M, C plus or minus 2M, and so on. The modulation index controls how many of these sidebands are loud enough to hear. Q: What is the modulation index? A: The modulation index is the depth of modulation divided by the modulator frequency. A higher index produces more audible sidebands and a brighter, richer tone, while a low index keeps the sound close to a pure sine. It does not change the ratio, only the brightness. Q: Why is the DX7 ratio table useful? A: Yamaha's DX7 quantised operator ratios to a fixed set of coarse and fine values, and those ratios became the basis for thousands of classic 1980s patches. Knowing which ratios give electric pianos, basses, brass, or bells is a fast way to dial in usable FM sounds. #### Grounding Electrode System Resistance Calculator URL: https://geratools.com/grounding-electrode-resistance-calculator Uses the Dwight formula for a driven ground rod and a parallel-efficiency model to estimate the resistance of one or more rods from soil resistivity, rod length, and diameter. Checks the NEC 250.53 / 250.56 single-rod 25-ohm rule for electricians and low-voltage techs. How to use: 1. Enter soil resistivity: Type the soil resistivity in ohm-metres. Use a measured value from a soil test, or a typical figure (around 100 ohm-m for moist loam) if you do not have one. 2. Choose rod dimensions and quantity: Pick the rod length, diameter, and how many rods you plan to drive in parallel. Standard rods are 8 ft long and 5/8 in diameter. 3. Read the estimated resistance: The calculator shows the single-rod resistance, the combined resistance for multiple rods, and whether the result meets the NEC 25-ohm single-rod allowance. FAQ: Q: What is the Dwight formula? A: The Dwight formula gives the earth resistance of a single driven rod: R = (rho / (2 pi L)) times (ln(4L/d) minus 1), where rho is soil resistivity in ohm-metres and L and d are the rod length and diameter in metres. It is the standard textbook model for a vertical electrode. Q: Why does soil resistivity matter so much? A: Resistance scales directly with soil resistivity, so it is the single biggest variable. Wet clay may be 10 ohm-m while dry sand or rock can exceed 1000 ohm-m. The same rod can read under 10 ohms in one soil and over 500 ohms in another. Q: Why don't parallel rods simply divide the resistance by N? A: Each rod has a resistance area in the soil. When rods are close together those areas overlap, so the combined resistance is higher than R divided by N. This tool applies an efficiency factor (about 0.86 for two rods spaced a rod-length apart) to model that overlap. Q: What is the NEC 25-ohm rule? A: NEC 250.53(A)(2) requires that a single made electrode (rod, pipe, or plate) with a resistance over 25 ohms be supplemented by an additional electrode. If a single rod measures 25 ohms or less, no second rod is required, though many installers drive two anyway. Q: Does this replace a real ground-resistance test? A: No. This is an estimate from idealized soil. Always confirm with a fall-of-potential test (3-point method) or a clamp-on ground tester, because real soil is layered and moisture varies with the seasons. Q: How do I hit 25 ohms in rocky or dry soil where rods read hundreds of ohms? A: You generally can't with 8-ft rods alone. Options are deeper driven rods that reach a moister layer, chemical ground-enhancement (backfill) electrodes, or a larger radial or ground-ring system. Because resistance scales with soil resistivity, high-resistivity sites need an engineered electrode system, not more short rods. Q: How far apart should supplemental ground rods be? A: At least one full rod length, and ideally two. Closer than that, the rods' resistance areas overlap so heavily that the second rod barely lowers the combined resistance — the parallel efficiency collapses and the copper is wasted. #### IPG Strip pH Range Selector for 2D-PAGE URL: https://geratools.com/isoelectric-focusing-strip-ph Enter a protein or proteome pI range and get the recommended immobilised pH gradient (IPG) strip — broad, medium, or narrow zoom range — for optimal first-dimension isoelectric focusing in 2D-PAGE proteomics, with rationale for each choice. For protein biochemists. How to use: 1. Enter your pI range: Type the lowest and highest pI you want to resolve. For a whole proteome use a wide range; for a few proteins enter their actual pI values. 2. Pick the focusing goal: Choose whether you want a survey of the whole proteome or a zoom-in that maximises resolution over a narrow pI window. 3. Read the recommended strip: The selector returns the IPG strip range that brackets your proteins, with a note on the resolution trade-off for that choice. FAQ: Q: What is an IPG strip? A: An immobilised pH gradient strip carries a fixed pH gradient cast into the gel. In the first dimension of 2D-PAGE, proteins migrate until they reach the pH equal to their pI, where they stop because their net charge is zero. The strip's pH range sets which proteins focus. Q: Why does strip range affect resolution? A: A narrow strip spreads a small pH window over the same physical length, so proteins with close pI values separate further apart. A broad strip surveys more of the proteome but packs spots closer together, lowering resolution per pH unit. Q: When should I use a narrow zoom strip? A: Use a narrow range (for example pH 4–7 or 6–9, or ultra-narrow 5–6) when your proteins of interest cluster in a pI window and you need to resolve closely spaced spots. Pair multiple overlapping narrow strips to cover the whole proteome at high resolution. Q: What if my proteins span the whole pH range? A: Use a broad-range strip such as pH 3–10 for an initial survey. It captures most cytosolic proteins in one run. Very acidic or very basic proteins may need dedicated low- or high-pH strips, since the extremes of a broad strip resolve poorly. Q: Does pI depend on conditions? A: Yes. IEF is run under denaturing conditions with urea and reductant, so the relevant pI is the denatured value. Post-translational modifications such as phosphorylation lower pI and create characteristic spot trains, which is part of what 2D-PAGE reveals. #### LDR Voltage Divider Calculator for DIY Electronics URL: https://geratools.com/ldr-voltage-divider-photoresistor Compute the optimal fixed series resistor for an LDR (photoresistor) voltage divider to maximise output swing at a target light level. Outputs the divider voltage, sensitivity and the geometric-mean resistor pick for Arduino and microcontroller light sensors. How to use: 1. Enter your LDR resistance range: From the LDR datasheet enter its bright (low) and dark (high) resistance in ohms — for a common GL5528 that is roughly 1 kΩ bright and 1 MΩ dark. 2. Set the supply voltage and divider position: Enter your supply (usually 3.3 V or 5 V) and choose whether the LDR sits on the top or bottom of the divider. 3. Read the recommended resistor: The tool returns the geometric-mean series resistor that centres the divider, plus the output voltage at the bright and dark extremes so you can see your usable swing. FAQ: Q: Why is the geometric mean the best resistor value? A: A voltage divider produces the largest output swing when the fixed resistor is the geometric mean of the LDR's two extremes, that is the square root of bright resistance times dark resistance. This centres the transition and spreads the voltage change evenly across the light range. Q: Should the LDR go on the top or bottom of the divider? A: Either works. With the LDR on the bottom (between the analog pin and ground) more light gives a lower voltage. With the LDR on top (between supply and the pin) more light gives a higher voltage. The tool computes both output extremes for whichever you choose. Q: What output voltage does the calculator report? A: It reports the divider output at the bright and dark resistance extremes. The output equals supply times R_lower divided by (R_upper plus R_lower), where the LDR and the fixed resistor occupy the upper and lower legs depending on the position you select. Q: What resistor should I actually buy? A: Round the geometric-mean result to the nearest common E12 value such as 10 kΩ or 33 kΩ. The exact value is not critical because microcontroller code thresholds the reading; being within a factor of two of the ideal still gives good sensitivity. Q: Does this work for a 3.3 V board like an ESP32? A: Yes. Set the supply to 3.3 V and the tool scales all output voltages accordingly. The recommended series resistor depends only on the LDR resistance range, not the supply, so it is the same for 3.3 V and 5 V boards. #### Runway Length Required Calculator URL: https://geratools.com/runway-length-required-calculator Estimate unfactored and 1.15-factored takeoff and landing field lengths over a 50 ft obstacle by correcting reference performance data for density altitude, weight, wind, and runway slope. A planning aid for runway compliance and obstacle clearance. How to use: 1. Enter the airport and air data: Type the field elevation, altimeter setting, and outside air temperature so the tool can derive pressure and density altitude. 2. Add weight, wind, and slope: Enter aircraft weight as a percentage of max gross, the wind component along the runway, and the runway gradient. 3. Read the factored lengths: The tool shows unfactored and 1.15-factored takeoff and landing distances over a 50 ft obstacle for runway compliance checks. FAQ: Q: Where do the base numbers come from? A: They are representative figures for a typical light single over a 50 ft obstacle at sea level, ISA, and max gross weight on a paved dry runway. The tool then scales them with standard correction factors. Always confirm against your actual aircraft POH. Q: Why apply a 1.15 factor? A: Many operating regulations and flight schools require a safety margin on the bare performance-chart distance. A 1.15 factor adds 15 percent to account for technique, surface, and chart optimism, giving a more conservative planning length. Q: How does density altitude affect the distance? A: Higher density altitude means thinner air, less engine power, and less wing lift, so the aircraft accelerates and climbs more slowly. The tool adds roughly 10 percent to the distance for every 1,000 ft of density altitude above sea level. Q: How is the wind component handled? A: A headwind shortens the ground roll and is credited at about 10 percent reduction per 10 kt, capped at 50 percent. A tailwind lengthens it sharply and is penalised at about 10 percent per 2 kt, reflecting how dangerous downwind operations are. Q: Can I trust this for a real flight? A: No. This is an estimator built on generic data for training and quick checks. The legal and safe source of performance numbers is the specific aircraft Pilot Operating Handbook for that aircraft, configuration, and conditions. #### Solar Array Tilt & Azimuth Output Calculator URL: https://geratools.com/solar-irradiance-tilt-calculator Uses a simplified geometric transposition model to show how changing roof tilt from 0 to 90 degrees and azimuth away from true south affects annual PV energy yield as a percentage of the south-facing, latitude-tilt optimum. Runs in your browser. How to use: 1. Enter your latitude: Type your site latitude in degrees, which sets the optimum tilt angle the result is compared against. 2. Set tilt and azimuth: Enter the array tilt from horizontal and the azimuth as degrees away from true south, where 0 is due south and negative is east, positive is west. 3. Read the yield estimate: The tool estimates annual energy as a percentage of the ideal south-facing, latitude-tilt array and shows the loss from your specific orientation. FAQ: Q: What is the optimum tilt for a fixed array? A: For maximising annual energy, a fixed array tilted roughly equal to the site latitude facing the equator is near optimal. Lower tilts favour summer, higher tilts favour winter, and this tool compares your chosen tilt against the latitude-equal benchmark. Q: How much does facing away from south cost? A: Modest azimuth errors are forgiving. Facing 30 degrees east or west of south typically loses only a few percent of annual yield, while east or west walls lose 15 to 20 percent. The model captures this falloff with a cosine-shaped azimuth penalty. Q: Is this model accurate enough to design a system? A: It is a quick screening estimate, not a substitute for hourly simulation tools like PVWatts or PVsyst that use real meteorological data. Use it to compare orientations and rule out poor ones, then confirm the chosen layout with a full simulation. Q: What does 0 percent azimuth mean? A: Azimuth here is the deviation from true south, so 0 means the array faces due south, which is optimal in the northern hemisphere. Enter negative values for east-facing and positive for west-facing. Southern-hemisphere sites should mirror this around due north. Q: Why does a flat array still produce a lot? A: A horizontal array, 0 degrees tilt, captures diffuse light from the whole sky and still yields 85 to 90 percent of the optimum in many climates. It is azimuth-independent but collects dust and rain poorly, which the geometric model does not penalise. #### Solar Array Shading Loss Estimator URL: https://geratools.com/solar-shading-loss-estimator Takes an obstruction's azimuth, elevation angle, and width plus the share of array affected to estimate the irradiance-weighted fraction of daylight blocked and the resulting annual PV energy loss. Runs in your browser. How to use: 1. Describe the obstruction: Enter the azimuth the obstruction sits at as seen from the array, its elevation angle above the horizon, and how wide it appears in degrees. 2. Set the affected share: Enter the percentage of the array that falls into shadow when the obstruction blocks the sun, accounting for string layout and module-level electronics. 3. Read the loss estimate: The tool walks the equinox sun path, weights each hour by clear-sky irradiance, and returns the fraction of daylight blocked and the approximate annual energy loss. FAQ: Q: How does the tool decide when panels are shaded? A: For each hour of the day it computes the sun's elevation and azimuth, then marks that hour shaded whenever the sun is lower than the obstruction's elevation angle and falls within the obstruction's angular width. Midday hours count more because the sun delivers more energy then. Q: Why does it use the equinox sun path? A: The equinox is a fair middle-of-the-road reference: winter sun runs lower and causes more shading, summer sun runs higher and causes less. Using the equinox gives an annual-average style estimate without needing a full year of weather data. Q: What is the obstruction elevation angle? A: It is the angle from the horizontal up to the top of the obstruction as measured from the array. A tall tree close to the panels has a high elevation angle; a distant ridge on the horizon has a low one. A Solar Pathfinder or inclinometer measures it directly. Q: Why enter the share of array affected separately? A: A shadow that covers a quarter of the modules does not erase a quarter of all output unless wiring matches. With module-level optimizers or microinverters the loss tracks the shaded area closely, so the affected-share input lets you reflect your layout. Q: Is this accurate enough to design around? A: It is a fast planning estimate to compare sites and obstructions, not a bankable production number. For a final design run a TMY-based simulation in tools like PVsyst or SAM and confirm with an on-site shade reading. #### TikTok Engagement Rate Calculator URL: https://geratools.com/tiktok-engagement-rate-calculator Enter follower count, likes, comments, shares, and saves to compute TikTok-specific engagement rate using the formula brands and agencies use, with benchmark comparisons by account size. How to use: 1. Enter your reach metric: Type your follower count, or switch to views if you want engagement rate by reach for a single video. 2. Add the interactions: Enter likes, comments, shares, and saves from the video or from your recent average. 3. Read your rate and benchmark: The tool sums interactions, divides by your reach metric, and compares the result against typical TikTok benchmarks for your account size. FAQ: Q: How is TikTok engagement rate calculated? A: Engagement rate is total interactions divided by your reach metric, times 100. The standard formula by followers is (likes + comments + shares + saves) divided by followers. By views it uses video views as the denominator, which better reflects how a single post performed. Q: Should I use followers or views as the denominator? A: Use followers for an account-level rate comparable to brand-deal benchmarks. Use views for a per-video rate, which is often fairer on TikTok because videos regularly reach far beyond your follower count through the For You feed. Q: What is a good TikTok engagement rate? A: TikTok runs higher than most platforms. By followers, 4 to 5 percent is solid for mid-size accounts, with smaller accounts often exceeding 10 percent and very large accounts settling lower. By views, 3 to 6 percent is a healthy band. Q: Do saves and shares count toward engagement? A: Yes. On TikTok, saves and shares are strong signals of value and are included in the engagement formula alongside likes and comments. Shares in particular drive reach, so a high share rate is a very good sign. Q: Why does my engagement rate drop as I grow? A: Larger audiences contain more passive followers, so the percentage that interacts naturally falls even as raw numbers rise. This is normal across every platform, which is why benchmarks are tiered by account size. #### Water Hammer Arrestor Sizing Calculator URL: https://geratools.com/water-hammer-arrestor-sizing Look up the PDI-WH 201 water hammer arrestor size code (A through F) from the number and type of protected fixtures, then map it to a nominal connection size. Built for plumbers installing shock arrestors on washers, dishwashers, and solenoid valves. How to use: 1. Enter the protected fixtures: Type how many of each fixture type the arrestor will protect on that supply branch. Each fixture has a standard Water Supply Fixture Unit (WSFU) value. 2. Read the total load: The tool sums the fixture units and looks up the matching PDI size letter from the WH-201 rating ranges (A is smallest, F is largest). 3. Select the arrestor: Buy an arrestor rated at or above your total fixture units, and install it close to the quick-closing valve it protects. FAQ: Q: What is PDI-WH 201? A: PDI-WH 201 is the Plumbing & Drainage Institute standard that rates water hammer arrestors by the fixture-unit load they can absorb. It assigns a size letter from A to F, where A handles 1–11 fixture units and F handles up to 330. Q: What size arrestor does a single washing machine need? A: A clothes washer is about 4 fixture units, which falls inside Size A (1–11 units). Almost every single-appliance install for a washer, dishwasher, or ice maker uses the common Size A mini arrestor. Q: Where should the arrestor be installed? A: Install it on the supply branch as close as practical to the quick-closing or solenoid valve that causes the shock. Mounting it far away lets the pressure spike build before the arrestor can absorb it. Q: Do arrestors have a check digit or expire? A: There is no checksum involved in sizing — it is purely a fixture-unit lookup. Modern piston-type arrestors are sealed and maintenance-free, unlike old air-chamber stubs that waterlog over time. Q: Does a larger arrestor ever hurt? A: Oversizing is safe but wastes money and space. The goal is to meet or slightly exceed the protected fixture-unit load, then verify against the specific manufacturer's published PDI rating. #### Contribution Margin Calculator URL: https://geratools.com/contribution-margin-calculator Free contribution margin calculator. Enter your selling price, variable costs, fixed costs and units sold to see contribution margin per unit, CM ratio, total CM, operating profit, break-even point (units and revenue), margin of safety and degree of operating leverage. Runs entirely in your browser. How to use: 1. Enter your selling price per unit: Type the price at which you sell one unit of your product or service. 2. Enter variable cost per unit: Add all costs that change with each unit produced or sold — materials, direct labour, packaging, sales commission, and so on. 3. Enter total fixed costs for the period: Add costs that stay the same regardless of output — rent, salaries, insurance, depreciation, and subscriptions. 4. Enter the number of units sold: Type the actual or forecast volume for the same period as your fixed costs. 5. Read the results: The calculator shows CM per unit, CM ratio, total CM, operating profit, break-even units and revenue, margin of safety, and degree of operating leverage — all updated as you type. FAQ: Q: What is contribution margin? A: Contribution margin (CM) is selling price minus all variable costs per unit. It is the slice of each sale that "contributes" first to covering fixed costs and then — once fixed costs are fully covered — to profit. A CM of zero means you break even on every unit before fixed costs; a negative CM means every extra unit sold makes the loss bigger. Q: How is contribution margin ratio calculated? A: CM ratio (CMR) = contribution margin per unit divided by selling price, expressed as a percentage. A CMR of 40 % means that for every pound of revenue, 40 pence is available to cover fixed costs and profit. It is also the slope of the profit line in a cost-volume-profit (CVP) chart. Q: How does the break-even point formula work? A: Break-even units = Fixed costs divided by CM per unit. Break-even revenue = Fixed costs divided by CM ratio. At the break-even point total contribution margin exactly equals total fixed costs, so operating profit is zero. Selling one more unit beyond that point generates pure profit equal to the CM per unit. Q: What is the margin of safety? A: Margin of safety = actual (or forecast) units sold minus break-even units. It tells you how far sales can fall before you start making a loss. A 30 % margin of safety means revenue could drop by almost a third before you hit break-even — a useful cushion to know before signing a long lease or hiring. Q: What does degree of operating leverage mean? A: Degree of operating leverage (DOL) = total contribution margin divided by operating profit. It shows how sensitive your profit is to a change in revenue. A DOL of 5 means a 10 % rise in sales produces a 50 % rise in operating profit — and equally a 10 % fall in sales produces a 50 % fall in profit. DOL is highest when you are just above break-even and falls as profit grows relative to fixed costs. Q: What is the difference between contribution margin and gross profit? A: Gross profit subtracts cost of goods sold (COGS) from revenue; COGS often mixes fixed manufacturing overhead with variable costs. Contribution margin separates costs strictly by behaviour — variable versus fixed — making it the correct metric for break-even analysis, pricing decisions, and short-run make-or-buy choices. The two figures coincide only in businesses with no fixed manufacturing overhead. #### Working Capital Calculator URL: https://geratools.com/working-capital-calculator Free working capital calculator. Compute net working capital, current ratio, quick ratio, cash ratio, DSO, DIO, DPO and cash conversion cycle instantly — 100% in your browser. How to use: 1. Enter your current assets: Fill in cash, short-term investments, accounts receivable, inventory and any other current assets from your balance sheet. 2. Enter your current liabilities: Add accounts payable, short-term debt, accrued liabilities and other obligations due within 12 months. 3. Add operating figures for cycle analysis: Optionally enter annual net sales, COGS and total assets to unlock DSO, DIO, DPO, CCC and working capital turnover. 4. Read the instant results: The calculator shows net working capital, all three liquidity ratios, a health status badge and your full cash conversion cycle breakdown. FAQ: Q: What is working capital? A: Working capital is the difference between a company's current assets and current liabilities: WC = Current Assets minus Current Liabilities. A positive figure means the business has more liquid resources than short-term obligations; a negative figure is a warning that near-term cash flow may be strained. Q: What is a good current ratio? A: A current ratio between 1.5 and 2.0 is generally considered healthy for most industries. Below 1.0 means current liabilities exceed current assets — a potential liquidity risk. Above 3.0 can indicate that cash is sitting idle rather than being deployed productively. Ratios vary significantly by sector: retailers often operate comfortably below 1.5 thanks to fast inventory turnover, while manufacturers may target higher buffers. Q: How does the quick ratio differ from the current ratio? A: The quick ratio (also called the acid-test ratio) removes inventory from the numerator because inventory can take weeks or months to convert to cash. Formula: Quick Ratio = (Cash + Short-term Investments + Receivables) / Current Liabilities. A quick ratio above 1.0 is generally considered safe; below 0.7 may signal liquidity pressure if receivables slow down. Q: What is the cash conversion cycle (CCC)? A: The CCC measures how many days cash is tied up in the operating cycle: CCC = DSO + DIO minus DPO. A lower (or negative) CCC means the business collects cash from customers before it must pay suppliers — a sign of strong working capital management. Negative CCCs are common in fast-moving retail and subscription businesses. Q: How do I reduce my cash conversion cycle? A: Three levers: (1) Reduce DSO by invoicing promptly, offering early-payment discounts, and chasing overdue accounts. (2) Reduce DIO by improving demand forecasting, adopting just-in-time inventory, and clearing slow-moving stock. (3) Increase DPO by negotiating longer payment terms with suppliers — without damaging relationships. Q: Is this calculator suitable for UK limited companies? A: Yes. The formulas are industry-standard and apply to any company regardless of jurisdiction. UK-specific considerations such as VAT recoverable, corporation tax liabilities and directors' loan accounts can be slotted into the "other current assets" or "other current liabilities" fields as appropriate. #### ARR Calculator URL: https://geratools.com/arr-calculator Free ARR calculator for SaaS founders and operators. Enter your MRR components — new, expansion, churn, contraction, reactivation — and instantly see ARR, Net Revenue Retention (NRR), Gross Revenue Retention (GRR), monthly growth rate and months to double. 100% browser-based. How to use: 1. Enter your starting MRR: Type the monthly recurring revenue you had at the beginning of the period (e.g. the start of the month or quarter). 2. Break down MRR movements: Fill in New MRR (from brand-new customers), Expansion MRR (upgrades/upsells), Churned MRR (cancellations), Contraction MRR (downgrades) and Reactivation MRR (returning customers). 3. Add your customer count: Enter the number of active paying customers to see ARR per customer alongside the headline figures. 4. Read the MRR bridge and retention metrics: The calculator shows ending MRR, ARR, Net Revenue Retention, Gross Revenue Retention, monthly growth rate and estimated months to double. FAQ: Q: What is ARR and how is it calculated? A: ARR (Annual Recurring Revenue) is the annualised value of all active subscription contracts. The formula is ARR = Ending MRR × 12, where Ending MRR = Starting MRR + New MRR + Expansion MRR + Reactivation MRR − Churned MRR − Contraction MRR. It is the single most-watched north-star metric for SaaS businesses because it captures the predictable, recurring component of revenue and strips out one-off payments. Q: What is Net Revenue Retention (NRR) and what is a good number? A: NRR measures how much revenue you retain and grow from your existing customer base after accounting for expansions, contractions and churn. Formula: NRR = (Starting MRR + Expansion + Reactivation − Churn − Contraction) / Starting MRR × 100. An NRR above 100% means existing customers generate more revenue than you lose — the business can grow ARR even with zero new customer acquisition. World-class SaaS companies (Snowflake, Twilio at peak) have reported NRR above 130%. 100–110% is healthy; below 100% signals retention problems that will limit growth. Q: What is the difference between NRR and GRR? A: Gross Revenue Retention (GRR) measures retention excluding any expansion revenue — it only captures churn and contraction. GRR = (Starting MRR − Churn − Contraction) / Starting MRR × 100, capped at 100%. GRR is always lower than or equal to NRR. GRR above 90% is considered excellent for a broad SaaS product; above 95% for enterprise. GRR answers "how much of our existing base do we keep?", while NRR answers "how much do we grow within the existing base?" Q: What is the MRR bridge? A: The MRR bridge is a waterfall decomposition that shows exactly how each MRR component contributes to the change from starting MRR to ending MRR. It separates positive flows (New, Expansion, Reactivation) from negative flows (Churn, Contraction) so you can see at a glance whether growth is driven by acquisition, upsell or reactivation, and where the largest drag is coming from. Investors and finance teams use MRR bridge charts in board decks to tell the story of growth momentum. Q: How do I use the Rule of 70 to estimate months to double ARR? A: The Rule of 70 is a quick approximation: months to double ≈ 70 / monthly growth rate (%). For example, if your MRR grows by 5% per month, you double roughly every 70 / 5 = 14 months. It is analogous to the Rule of 72 used in compound interest. The exact formula is ln(2) / ln(1 + r) ≈ 0.693 / r for small r, and 70/r is close enough for practical planning purposes at growth rates under 20%/month. Q: Should I use ARR or MRR as my north-star metric? A: Use MRR for operational cadence (monthly board updates, cohort analysis, churn tracking) and ARR for strategic conversations with investors, acquirers and your leadership team. ARR is standard in enterprise SaaS sales because contracts are annual; MRR is more natural for monthly-billed consumer SaaS. The two are identical in substance (ARR = MRR × 12) — the choice is about communication convention, not calculation. #### CPC Calculator — Cost Per Click, CTR, ROAS & CPA URL: https://geratools.com/cpc-calculator Free CPC calculator for Google Ads, Facebook Ads and any paid channel. Enter your ad spend and clicks to get CPC, CTR, CPM, CPA, ROAS and profit. Solve for CPC, spend, or clicks. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose what to solve for: Pick CPC (default), Ad Spend, or Clicks from the three toggle buttons at the top to unlock that field as the output. 2. Enter your campaign numbers: Fill in your ad spend, number of clicks, and total impressions from your ad platform dashboard. 3. Add conversion data: Enter your conversions and value per conversion to see CPA, ROAS, and campaign profit or loss. 4. Read your results: The calculator shows CPC, CTR, CPM, CPA, conversion rate, ROAS and net profit alongside a CPC rating benchmark. FAQ: Q: What is CPC and how is it calculated? A: CPC stands for Cost Per Click. It is calculated as: CPC = total ad spend ÷ total clicks. For example, spending £500 to receive 250 clicks gives a CPC of £2.00. It measures how much you pay every time someone clicks your ad. Q: What is a good CPC for Google Ads? A: There is no universal "good" CPC — it varies wildly by industry, keyword, and geography. B2C e-commerce CPCs often sit between $0.50–$2.00, while competitive B2B or legal keywords can exceed $50. What matters is whether your CPC is below your revenue per click. Use the ROAS and profit figures in this calculator to judge efficiency rather than comparing raw CPC in isolation. Q: What is the difference between CPC, CPM, and CPA? A: CPC (Cost Per Click) is what you pay each time someone clicks your ad. CPM (Cost Per Mille) is the cost per 1,000 impressions — useful for awareness campaigns where reach matters. CPA (Cost Per Acquisition) is the spend divided by the number of conversions, showing the cost to acquire one customer or lead. All three are shown by this calculator from the same inputs. Q: What does ROAS mean and what is a good ROAS? A: ROAS stands for Return On Ad Spend. It equals (total conversion value) ÷ (ad spend). A ROAS of 4× means you earn £4 in revenue for every £1 spent. A ROAS below 1× means the campaign is unprofitable at the revenue level entered. Many e-commerce businesses target 3–5× ROAS, but the break-even ROAS depends on your gross margins: if margin is 25%, you need at least 4× ROAS to cover the spend. Enter your margin-adjusted value per conversion to get the most accurate reading. Q: How do I use the solver modes (CPC / Spend / Clicks)? A: Toggle the three buttons at the top to choose what to solve for. In CPC mode you enter spend and clicks and the calculator tells you the CPC. In Spend mode you enter a target CPC and click volume and it returns the required budget. In Clicks mode you enter a CPC and a budget and it returns how many clicks you can expect — useful for forecasting before a campaign launches. Q: What is CTR and how does it affect CPC? A: CTR (Click-Through Rate) equals (clicks ÷ impressions) × 100. A higher CTR improves your Google Quality Score, which can lower your actual CPC even at the same bid, because Google rewards relevance. Improving ad copy or targeting to raise CTR is often the fastest way to reduce effective CPC without cutting bids. ### Tax & Wages #### VAT & Sales Tax Calculator URL: https://geratools.com/vat-calculator Free VAT, GST and sales-tax calculator. Add tax to a net price or strip tax out of a gross price, with a multi-country rate dropdown and full breakdown. Runs entirely in your browser. How to use: 1. Choose add or remove: Add-tax mode treats your amount as the net price; remove-tax mode treats it as the gross (tax-inclusive) price. 2. Pick a country: Select a country to auto-fill its standard rate, or type a custom rate. 3. Read the breakdown: See the net, the tax amount and the gross total instantly. FAQ: Q: How do I remove VAT from a price? A: Divide the gross price by (1 + rate). For 20% VAT that's gross ÷ 1.20. Choose "remove tax" and the calculator does it for you. Q: Which countries are included? A: A starter list of common VAT/GST countries with their standard rates — plus a custom rate field so you can enter any rate, including reduced rates or US state sales tax. Q: Is anything sent to a server? A: No. The calculation runs entirely in your browser. Q: How do I add 20% VAT to a price? A: Multiply the net price by the rate and add it on. For £100 at 20% VAT, tax = £100 × 0.20 = £20, so the gross is £120. Use "add tax" mode and the calculator shows net, tax and gross. Q: How much VAT is in a £120 inclusive price at 20%? A: Divide the gross by 1.20 to get the net: £120 ÷ 1.20 = £100, so the VAT is £20. This is the reverse calculation — pick "remove tax" mode. Q: What standard rates are preset? A: Presets include the UK (20%), Ireland (23%), Germany (19%), France (20%), Spain (21%), Italy (22%), Netherlands (21%), Australia (10% GST), New Zealand (15% GST), Canada (5% GST), India (18% GST), Singapore (9% GST), UAE (5%) and South Africa (15%), plus a US sales-tax field defaulting to 8.25%. Q: Can I use this for reduced VAT rates or US sales tax? A: Yes. The rate field is editable, so you can type any rate — a reduced VAT rate, a zero rate, or a specific US state and local combined sales-tax rate. #### Take-Home Pay & Salary Tax Calculator URL: https://geratools.com/take-home-pay-calculator Free take-home pay and salary-tax calculator for the UK, US and Germany. See your net monthly and annual salary after income tax and social contributions, with a full breakdown. Runs entirely in your browser. How to use: 1. Enter your annual gross salary: Type your salary before any tax or deductions. 2. Choose your country: Select the UK, US or Germany to apply the right tax bands and social contributions. 3. Read your take-home: See your net annual, monthly and weekly pay, plus a full breakdown and effective tax rate. FAQ: Q: Which countries are supported? A: The UK (2024/25), US (federal, single filer, 2024) and Germany (single, approx. 2024) to start. The locale data is structured so more countries can be added easily. Q: How accurate is the calculation? A: It uses the headline income-tax bands, personal allowance/standard deduction and employee social contributions for each locale. It's a close estimate for guidance — it excludes pensions, student loans, state taxes and other adjustments. Q: Is my salary information private? A: Completely. The calculation runs entirely in your browser and nothing is sent anywhere. Q: How is take-home pay calculated? A: Take-home = gross − income tax − social contributions. Income tax is charged on gross minus your tax-free allowance using progressive (marginal) bands, so only the slice of income inside each band is taxed at that band rate. Social contributions (UK National Insurance, US FICA, German social insurance) are charged on gross. Q: What is the effective tax rate? A: The effective rate is the total of income tax plus social contributions divided by your gross salary, expressed as a percentage. It is always lower than your top marginal band, because lower bands are taxed at lower rates. Q: Why does my UK personal allowance shrink at high salaries? A: For UK earners, the £12,570 personal allowance is tapered by £1 for every £2 of income above £100,000, so it reaches zero at £125,140. The calculator applies this taper automatically. Q: Does this include pension or student loan deductions? A: No. The result covers income tax and statutory social contributions only. Workplace pension contributions, student loan repayments, UK Scottish bands, US state taxes and German church tax are not deducted. #### Cycling Elevation & VAM Calculator URL: https://geratools.com/cycling-elevation-gain-estimate Enter climb elevation gain and ascent time to compute VAM — the climbing speed metric used by professional cycling analysts to estimate power output and compare performances on categorised climbs. How to use: 1. Enter elevation gain: Type the total vertical metres climbed, taken from the bottom and top altitude of the climb or your GPS file. 2. Enter ascent time: Add how long the climb took in minutes and seconds. Use the time from the base of the climb to the summit only. 3. Read your VAM: The tool divides vertical metres by time in hours to give VAM and estimates a typical gradient-adjusted power-to-weight figure. FAQ: Q: What does VAM stand for? A: VAM is the Italian Velocità Ascensionale Media, meaning average ascent speed. It expresses how many vertical metres you climb per hour and was popularised by coach Michele Ferrari as a quick way to compare climbing efforts. Q: What is a good VAM? A: Recreational climbers manage 600-900 VAM, strong amateurs reach 1,000-1,400, and Grand Tour contenders can sustain 1,600-1,800 VAM on a steep summit finish. VAM falls on shallower gradients because gravity does less of the resistance. Q: Can VAM estimate my power-to-weight? A: On steep climbs of 7% or more there is a rough proportionality: W/kg is approximately VAM divided by a gradient factor near 100. The estimate here uses that relationship and is most accurate on consistent, steep climbs with little wind or descending. Q: Why does gradient affect VAM? A: On a gentle gradient more of your power goes into overcoming air and rolling resistance rather than lifting your mass, so even at the same wattage your vertical speed is lower. That is why VAM comparisons are fairest between climbs of similar steepness. Q: Does VAM account for my weight? A: VAM itself is independent of rider weight — it only measures vertical speed. The power estimate, however, is expressed in watts per kilogram, which already normalises for weight and is the metric that decides climbing pace. #### Earned Income Tax Credit (EITC) Calculator URL: https://geratools.com/earned-income-tax-credit-calculator Estimate your 2026 Earned Income Tax Credit using the official credit rates and phase-out by number of qualifying children (0–3+). Applies the credit rate, plateau, and phase-out rate to earned income and AGI to show your estimated refundable EITC. How to use: 1. Select your children: Choose how many qualifying children you have — none, one, two, or three or more — to load the correct credit rate and maximum. 2. Enter income: Enter your earned income and your adjusted gross income; the calculator uses the greater of the two for the phase-out. 3. Read your EITC: The tool shows the phase-in amount, the tier maximum, the phase-out reduction, and your estimated Earned Income Tax Credit. FAQ: Q: What is the maximum EITC for 2026? A: The maximum 2026 Earned Income Tax Credit is about $649 with no children, $4,328 with one child, $7,152 with two children, and $8,046 with three or more qualifying children. The credit phases in, plateaus at these maximums, then phases out. Q: How does the EITC phase in and out? A: The credit grows as a percentage of earned income — 7.65% with no kids up to 45% with three or more — until it hits the tier maximum. As income rises past the phase-out threshold, it shrinks by the phase-out rate (15.98% to 21.06%) until it reaches zero. Q: Does the EITC use earned income or AGI? A: Both. The phase-in is based on earned income (wages and self-employment). The phase-out uses the greater of your earned income and AGI, which can reduce the credit when investment or other income pushes your AGI above the earned amount. Q: Why is my EITC zero at higher incomes? A: Each tier has an income ceiling where the phase-out fully eliminates the credit. With no children that happens around $19,000 of income; with three or more children the credit can extend toward the high $50,000s. Above your tier's ceiling the EITC is zero. #### San Francisco Minimum Wage & Overtime Calculator URL: https://geratools.com/san-francisco-minimum-wage-overtime-calculator Calculate hourly, weekly, and overtime pay using San Francisco's current $18.67/hr minimum wage. Applies California overtime rules of 1.5x over 8 hours a day or 40 a week and 2x over 12 hours a day. Runs in your browser. How to use: 1. Enter your hourly rate: Type your hourly wage, which defaults to San Francisco's $18.67 minimum. Rates below the minimum are flagged. 2. Enter your hours: Type the hours you worked each day of the week so the tool can apply California's daily and weekly overtime rules. 3. Read your gross pay: The tool splits hours into regular, time-and-a-half, and double-time buckets and totals your gross weekly pay. FAQ: Q: What is the minimum wage in San Francisco? A: San Francisco's local minimum wage is currently $18.67 per hour, above the California statewide minimum. Most employers in the city must pay at least this rate, with some sector-specific rates higher. The tool flags any rate below the local minimum. Q: How does California overtime work? A: California pays 1.5x for hours over 8 in a day or over 40 in a week, and 2x (double time) for hours over 12 in a single day. This is more generous than the federal weekly-only rule, so the tool applies the daily thresholds first. Q: Why apply daily overtime before weekly? A: California requires daily overtime, so each day's hours over 8 earn 1.5x and over 12 earn 2x regardless of the weekly total. The tool computes daily overtime per day, then adds any additional weekly overtime so hours are never double-counted. Q: Are tipped workers paid less? A: No. California does not allow a tip credit, so tipped workers must still receive the full minimum wage before tips. Tips are on top of the hourly minimum, unlike many other states that permit a lower tipped wage. Q: Does this include taxes or deductions? A: No. This calculates gross pay only — your earnings before income tax, payroll tax, and any deductions. Your take-home pay will be lower after federal, state, Social Security, and Medicare withholdings. #### Saudi Arabia VAT Calculator (15%) URL: https://geratools.com/saudi-vat-calculator Free Saudi Arabia VAT calculator at the 15% standard rate (raised from 5% in July 2020). Add VAT to a net price by multiplying by 1.15, or extract VAT from a VAT-inclusive total by dividing by 1.15. Runs entirely in your browser. How to use: 1. Enter the amount: Type the SAR amount — the net price if you are adding VAT, or the inclusive price if you are extracting it. 2. Choose the direction: Select add to apply 15% VAT to a net price, or extract to strip VAT from a VAT-inclusive total. 3. Read the result: The tool reports the net amount, the 15% VAT and the gross total. FAQ: Q: What is the VAT rate in Saudi Arabia? A: Saudi Arabia applies a flat 15% standard VAT rate. The rate was 5% from 2018 until it was tripled to 15% on 1 July 2020. There are no reduced rates; some supplies are zero-rated or exempt. Q: How do I add 15% VAT to a price? A: Multiply the net (exclusive) amount by 1.15. The VAT itself equals the net multiplied by 0.15. For example, SAR 100 net becomes SAR 115 gross with SAR 15 VAT. Q: How do I extract VAT from a VAT-inclusive price? A: Divide the gross by 1.15 to find the net, then subtract to get the VAT. A SAR 115 inclusive price contains SAR 15 of VAT on a SAR 100 net. Q: When did Saudi VAT change to 15%? A: The standard rate rose from 5% to 15% on 1 July 2020 as part of fiscal measures during the pandemic. The 15% rate has remained in place since. Q: Does this tool send my figures anywhere? A: No. All calculations run locally in your browser using JavaScript. No data is transmitted. #### New Hampshire Payroll Calculator URL: https://geratools.com/us-new-hampshire-payroll-calculator Free New Hampshire take-home pay calculator. Computes federal income tax withholding and FICA only. NH has never taxed wages, and its Interest and Dividends Tax was fully repealed in January 2025, making it income-tax free. Runs in your browser. How to use: 1. Enter your gross pay: Type your annual gross salary and pick your federal filing status — single or married filing jointly. 2. Add pre-tax deductions: Enter any 401(k) or pre-tax benefit contributions so the calculator reduces your federal taxable income correctly. 3. Read your take-home pay: The tool shows federal income tax, Social Security, Medicare and your estimated net annual and monthly pay. FAQ: Q: Does New Hampshire tax wages? A: No. New Hampshire has never imposed a tax on earned wages or salaries. Your only mandatory paycheck taxes are federal income tax withholding and FICA, so NH take-home pay on a salary is the same as in a fully no-income-tax state. Q: What happened to the NH Interest and Dividends Tax? A: New Hampshire historically taxed investment income (interest and dividends) at 5%, but the rate was phased down and the tax was fully repealed effective January 2025. From the 2025 tax year onward, New Hampshire has no income tax of any kind. Q: How is Social Security tax calculated? A: Social Security is 6.2% of wages up to the annual wage base of $176,100 for 2025. Earnings above that cap are not subject to Social Security tax, so high earners pay a fixed maximum amount. Q: How is Medicare tax calculated? A: Medicare is 1.45% of all wages with no cap. An Additional Medicare Tax of 0.9% applies to wages above $200,000 (single) or $250,000 (married filing jointly). Q: Is my salary data sent anywhere? A: No. All calculations run entirely in your browser using the 2025 federal tax tables. Nothing you type is transmitted or stored anywhere. #### Vikram Samvat Converter URL: https://geratools.com/vikram-samvat-converter Free Vikram Samvat converter. Convert a Gregorian (CE) date to the Hindu/Nepali Vikram Samvat (VS) year and back, using the correct +56 / +57 spring new-year offset. Privacy-first and runs entirely in your browser — nothing is sent anywhere. How to use: 1. Choose a direction: Pick Gregorian to Vikram Samvat, or Vikram Samvat to Gregorian. 2. Enter the date: Type the year, month and day so the tool can apply the correct new-year offset. 3. Read the converted year: The result shows the converted year and which offset (+56 or +57) was applied. FAQ: Q: Why is the offset sometimes 56 and sometimes 57 years? A: The Vikram Samvat new year begins in spring (around mid-April). Dates before that new year use a +56 offset and dates on or after it use +57, so the month and day matter, not just the year. Q: What is the Vikram Samvat epoch? A: Vikram Samvat counts from 57 BCE, traditionally tied to King Vikramaditya. Because the epoch sits 56–57 years before the Common Era, VS years run that much ahead of CE. Q: When does the Vikram Samvat new year fall? A: It begins in spring — around 14 April (Mesha Sankranti / Nepali Baisakh 1). The tool uses this fixed boundary to decide whether a date takes the +56 or +57 offset, which is correct to the year. Q: Is Vikram Samvat the same as Bikram Sambat? A: Yes — Bikram Sambat is the Nepali name for the same calendar and is Nepal's official calendar. The numbers and offsets are identical. Q: How do I convert a VS year back to CE? A: Subtract the offset: CE = VS − 56 for dates before the spring new year, or VS − 57 on or after it. Switch the direction selector and the tool does this for you. Q: How accurate is the conversion? A: The year-level conversion is exact when you provide the month and day, because it applies the correct spring new-year boundary. Vikram Samvat is lunisolar, so individual month and day lengths differ from the Gregorian calendar — for exact festival days consult a panchang. Q: Is anything I enter sent anywhere? A: No. This tool is privacy-first — the conversion runs locally in your browser and nothing leaves your device. #### Paycheck Splitter URL: https://geratools.com/paycheck-splitter Free paycheck splitter. Enter your take-home pay and instantly see how much goes to needs, wants and savings using 50/30/20, 70/20/10, six-jars or a fully custom split. Live doughnut chart, sliders and CSV export. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your take-home pay: Type the amount that actually lands in your account after tax, and choose whether it is weekly, fortnightly, monthly or annual. 2. Pick a preset or build your own: Start from 50/30/20, 70/20/10, aggressive saver or six-jars, then rename buckets, drag the sliders, or add your own categories. 3. Read the breakdown and export: The doughnut chart and needs/wants/savings roll-up update live. Click 'Scale to 100%' to balance, then export the plan as a CSV. FAQ: Q: What is the 50/30/20 budget rule? A: The 50/30/20 rule splits your take-home pay into three slices — 50% for needs (rent, bills, groceries, minimum debt payments), 30% for wants (eating out, hobbies, subscriptions) and 20% for savings and extra debt repayment. It was popularised by US Senator Elizabeth Warren and is a simple starting point because it works at almost any income level. Q: Should I use my gross or take-home pay? A: Always use take-home (net) pay — the amount that actually arrives in your account after income tax, national insurance or social security, and pension contributions. Budgeting from gross pay overstates what you can spend because a large slice never reaches you. Q: What counts as a 'need' versus a 'want'? A: Needs are things you genuinely cannot skip this month — housing, utilities, essential food, transport to work, insurance and minimum debt payments. Wants are everything that improves life but is optional — dining out, streaming, holidays, upgrades. If cancelling it would not threaten your home, health or job, it is a want. Q: Is 50/30/20 realistic in a high cost-of-living area? A: Often not. If rent alone eats 50% of your pay, switch to the 70/20/10 preset, which gives needs more room, or build a custom split. The tool lets you set any percentages and the 'Scale to 100%' button rebalances them, so you can model a budget that fits your real costs instead of forcing the textbook numbers. Q: How much of my paycheck should go to savings? A: 20% is the classic target, but the right number depends on your goals and age. If you are debt-free and chasing early retirement, the aggressive-saver preset pushes 40% into savings and investing. If you are paying down high-interest debt, treat that repayment as part of your savings slice — clearing 20% APR debt beats almost any investment. Q: Does this paycheck splitter store my income anywhere? A: No. Every calculation runs in your browser using JavaScript. Your pay figure and custom buckets are saved only to your own device via localStorage so the page remembers them next visit — nothing is ever sent to a server, and clearing your browser data removes it. #### Overtime Pay Calculator URL: https://geratools.com/overtime-pay-calculator Free multi-tier overtime pay calculator. Enter your regular hourly rate and hours, add as many overtime bands as you need (1.5x, 2x or any multiplier), and see regular pay, overtime pay, blended rate and annualised gross. Currency-agnostic and 100% in your browser. How to use: 1. Enter your regular rate and hours: Type your normal hourly pay rate and the number of hours paid at that base rate, then pick a currency (or no symbol) and a pay period such as week or month. 2. Add one or more overtime tiers: Each tier has a label, a number of hours and a multiplier (1.5 for time-and-a-half, 2 for double time). Add as many bands as your contract uses; each is paid at rate multiplied by its multiplier. 3. Read the breakdown and chart: The tool shows regular pay, each overtime band, the overtime subtotal, total gross pay, your blended hourly rate, the overtime share of gross and an annualised figure, with a bar chart of where the money comes from. FAQ: Q: How is overtime pay calculated? A: Regular pay is your base hours multiplied by your regular rate. Each overtime band is its hours multiplied by an effective rate, where the effective rate is your regular rate multiplied by that band's multiplier. Gross pay is regular pay plus every overtime band added together. Q: What does time-and-a-half mean? A: Time-and-a-half means each overtime hour is paid at 1.5 times your normal hourly rate. If you earn 20 an hour, those hours pay 30 each. Set a tier multiplier to 1.5 to model it. Q: How do I model double time on top of time-and-a-half? A: Add two tiers. Put the time-and-a-half hours in one band at a 1.5 multiplier and the double-time hours in a second band at a 2 multiplier. The breakdown shows each band separately and sums them into gross pay. Q: What is a blended hourly rate? A: The blended rate is your total gross pay divided by your total hours worked, including both regular and overtime hours. It tells you what every hour averaged out to once the overtime premium is spread across the whole shift. Q: Does this calculator deduct tax? A: No. It reports gross (pre-tax) pay only. Tax, national insurance, pension and other deductions depend on your country and personal situation, so pair this with a take-home or gross-to-net tool for an after-tax figure. Q: Is my pay information private? A: Yes. Every figure is computed locally in your browser and your draft is saved only in this browser's local storage. Nothing is uploaded to a server and no network request is made. ### Medical & Clinical #### Blood Alcohol Calculator (BAC) URL: https://geratools.com/blood-alcohol-calculator Free blood alcohol content (BAC) estimator using the Widmark formula. Enter your body weight, sex, number of drinks and time elapsed to estimate your blood alcohol concentration. For education only — never use to decide whether to drive. Runs entirely in your browser. How to use: 1. Enter your body weight and sex: Choose kg or lb, then enter your body weight and sex, which affect how alcohol distributes through the body. 2. Enter drinks and grams of alcohol: Type how many drinks you have had and the grams of pure alcohol in each (a UK unit is about 8 g, a US standard drink about 14 g). 3. Enter time elapsed: Add the hours since your first drink so the estimate accounts for alcohol your body has already eliminated. FAQ: Q: How is BAC estimated? A: The Widmark formula estimates BAC as alcohol grams ÷ (body weight in grams × r) × 100, where r is a distribution ratio (about 0.68 for men and 0.55 for women). It then subtracts roughly 0.015% per hour for the alcohol your body eliminates over time. Q: Can I rely on this to decide whether to drive? A: Absolutely not. This is an educational estimate only. Actual BAC varies enormously with food, hydration, medication, metabolism, health and the exact drink strength. If you have been drinking, do not drive — the only safe amount before driving is none. Q: How much alcohol is in one drink? A: It depends on the drink and country. A UK unit contains about 8 g of pure alcohol; a US standard drink about 14 g. A pint of 5% beer is roughly 2.3 UK units (about 18 g), and a 175 ml glass of 13% wine about 2.3 units. Enter the grams per drink that match what you drank. Q: How long does alcohol take to leave the body? A: The body eliminates alcohol at roughly 0.015% BAC per hour and this rate cannot be sped up by coffee, food or a cold shower. The calculator estimates the hours until your BAC returns to about zero, but individual rates vary. Q: Is my data private? A: Completely. Every figure is calculated inside your browser and nothing you enter is sent to a server or stored. #### APGAR Score Calculator URL: https://geratools.com/apgar-score Scores appearance, pulse, grimace, activity, and respiration on the 0–2 APGAR scale to produce a total with interpretation (normal, requires attention, or resuscitation). Built for midwives, neonatologists, and delivery-room nurses. Runs 100% in your browser. How to use: 1. Score each of the five signs: Rate Appearance, Pulse, Grimace, Activity, and Respiration from 0 to 2 based on the newborn's observed condition. 2. Read the total: The five values are summed to give a score out of 10, displayed with a colour-coded interpretation band. 3. Repeat at each interval: Reassess at 1, 5, and (if needed) 10 minutes after birth and record each total separately to track recovery. FAQ: Q: What is a normal APGAR score? A: A total of 7 to 10 is considered normal. A score of 4 to 6 is moderately low and the baby usually needs some assistance such as stimulation or suction. A score of 0 to 3 is critically low and indicates the need for resuscitation. Q: What do the five APGAR components stand for? A: APGAR is an acronym: Appearance (skin colour), Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), and Respiration (breathing effort). Each is scored 0, 1, or 2 for a maximum of 10. Q: When is the APGAR score taken? A: It is recorded at 1 minute and 5 minutes after birth. If the 5-minute score is below 7, scoring is repeated every 5 minutes up to 20 minutes. A 10-minute score is often documented after intervention. Q: Does a low APGAR mean long-term harm? A: Not necessarily. A low 1-minute score reflects the condition at birth, while the 5-minute score better reflects response to care. A single low score is not a reliable predictor of long-term neurological outcome on its own. Q: Is my data stored anywhere? A: No. The calculation runs entirely in your browser and nothing you enter is transmitted or saved on any server. #### BUN:Creatinine Ratio Calculator URL: https://geratools.com/blood-urea-nitrogen-creatinine-ratio Calculates the BUN:creatinine ratio in conventional units, or the urea:creatinine ratio in SI units, and classifies the pattern as pre-renal (above 20:1), intrinsic renal (10 to 20:1), or suggests a post-renal cause. For nephrology and general medicine. How to use: 1. Choose your units: Select conventional units (BUN mg/dL, creatinine mg/dL) or SI units (urea mmol/L, creatinine micromol/L) to match your lab report. 2. Enter the two values: Type the urea or BUN and the creatinine. The tool converts SI values to the standard BUN:creatinine basis before calculating. 3. Read the ratio and pattern: The tool shows the ratio and classifies it as pre-renal, intrinsic renal, or a possible post-renal pattern, with the caveats that apply. FAQ: Q: How is the SI ratio calculated? A: SI labs report urea in mmol/L and creatinine in micromol/L, so a direct ratio is not comparable to the US BUN:creatinine number. The tool converts urea to BUN by multiplying by 2.8 (BUN mg/dL = urea mmol/L × 2.8) and creatinine micromol/L to mg/dL by dividing by 88.4, then takes the ratio on the same conventional basis. Q: What does a high ratio mean? A: A BUN:creatinine ratio above about 20:1 suggests a pre-renal cause such as dehydration, blood loss, heart failure, or gastrointestinal bleeding, where the kidney reabsorbs urea avidly while creatinine rises less. It points to reduced renal perfusion rather than intrinsic kidney damage. Q: What does a normal or low ratio mean? A: A ratio of roughly 10:1 to 20:1 is the normal range and, in the context of a raised creatinine, suggests intrinsic renal disease such as acute tubular necrosis. A low ratio can also occur with low protein intake, liver disease, or over-hydration, which the tool notes as caveats. Q: Can this diagnose post-renal obstruction? A: Not on its own. Post-renal obstruction often raises the ratio like a pre-renal picture early on, then behaves like intrinsic disease as it persists. The tool flags that an elevated ratio with relevant symptoms warrants imaging to exclude obstruction; it cannot confirm it from the numbers alone. Q: What limits the ratio's reliability? A: Urea is affected by protein intake, gastrointestinal bleeding, steroids, catabolism, and liver function, while creatinine depends on muscle mass. High or low urea from these causes shifts the ratio independently of kidney perfusion, so always interpret it alongside the clinical picture and urinary indices. #### Obesity Class & Drug Dosing Weight Selector URL: https://geratools.com/bmi-obesity-class-drug-dosing Given weight, height, sex, and drug category, this tool computes BMI with obesity class and the four dosing weights, then recommends actual, ideal, adjusted, or lean body weight per published guidance. For obese-patient pharmacotherapy. How to use: 1. Enter the patient: Provide sex, actual body weight in kilograms, and height in centimetres so the tool can compute BMI and the body weights. 2. Choose the drug class: Select the medication category such as aminoglycoside, vancomycin, heparin, or propofol, each mapped to a recommended dosing weight. 3. Read the recommendation: The tool returns the recommended dosing weight along with BMI, obesity class, and all four body-weight values for comparison. FAQ: Q: Why do obese patients need a special dosing weight? A: Drugs distribute differently in fat and lean tissue. A water-soluble drug stays mostly in lean mass, so dosing on total weight overdoses it, while a fat-soluble drug spreads into adipose tissue. Choosing actual, ideal, adjusted, or lean weight matches the dose to where the drug actually goes. Q: How are the body weights calculated? A: Ideal body weight uses the Devine formula from height and sex. Adjusted body weight adds 40 percent of the difference between actual and ideal weight. Lean body weight uses the Janmahasatian equation, which incorporates BMI. Actual body weight is simply the measured weight. Q: Which drugs use which weight? A: As a general pattern, aminoglycosides use adjusted body weight, vancomycin and treatment-dose heparin use actual weight, neuromuscular blockers like rocuronium use ideal weight, and propofol induction uses lean body weight. The tool applies the recommended weight for the class you choose. Q: What do the obesity classes mean? A: BMI bands define them: 25 to 30 is overweight, 30 to 35 is class I obesity, 35 to 40 is class II, and 40 or above is class III, also called severe obesity. The class signals how far actual weight has diverged from ideal and how much the dosing-weight choice matters. Q: Can I prescribe directly from this? A: No. This is a teaching and reference aid using common guidance defaults. Real dosing also depends on renal and hepatic function, the indication, therapeutic drug monitoring, and local protocols. Always confirm against the product information and a clinical pharmacist before prescribing. #### Braden Scale for Pressure Injury Risk URL: https://geratools.com/braden-pressure-ulcer-risk Score the six Braden subscales — sensory perception, moisture, activity, mobility, nutrition, and friction/shear — to get a total Braden score, risk category, and matched preventive intervention guide. Runs in your browser. How to use: 1. Score each subscale: For each of the six domains, select the description that best matches the patient. Five domains score 1–4; friction and shear scores 1–3. 2. Read the total: The tool sums all six subscales into a total between 6 and 23, where a lower score means higher pressure injury risk. 3. Apply the interventions: Match the risk category to the listed preventive measures, from routine skin care up to a specialist support surface. FAQ: Q: What is the range of the Braden Scale? A: The total ranges from 6 to 23. Five subscales score 1 to 4 and friction/shear scores 1 to 3. A lower total indicates greater risk of developing a pressure injury, so 6 is the highest risk and 23 is no risk. Q: What Braden score is considered at risk? A: Most institutions treat a score of 18 or below as at risk and begin a prevention protocol. Common bands are 15–18 mild, 13–14 moderate, 10–12 high, and 9 or below very high risk. Q: Why does friction and shear only score 1 to 3? A: The original Bergstrom and Braden scale defines only three levels for the friction and shear subscale because no fourth level was clinically distinct. This is why the maximum total is 23, not 24. Q: How often should the Braden Scale be repeated? A: Reassess on admission, then at intervals set by local policy — often every 24 to 48 hours on acute wards — and whenever the patient's condition changes materially, such as new immobility, incontinence, or reduced intake. Q: Does a good Braden score rule out a pressure injury? A: No. The Braden Scale is a screening aid, not a guarantee. Clinical judgement, skin inspection, and individual risk factors such as existing wounds or poor perfusion must always be considered alongside the score. Q: Can the Braden Scale be used for children? A: The adult scale is not validated for paediatric patients. Use the Braden Q scale, the paediatric adaptation, or the newer Braden QD, which also scores medical-device-related risk — an increasingly common cause of pressure injuries in children. #### Creatinine Unit Converter (mg/dL to umol/L) URL: https://geratools.com/creatinine-unit-converter Converts serum and urine creatinine between mg/dL and µmol/L using the molar-mass factor of 88.42. Built for nephrologists, intensivists, and pharmacists working between American and European lab reports. Runs 100% in your browser. How to use: 1. Choose the direction: Select whether you are converting from mg/dL to µmol/L or the reverse. 2. Enter the creatinine value: Type the serum or urine creatinine value from your lab report into the field. 3. Read the converted result: The equivalent value appears instantly using the standard factor of 88.42. FAQ: Q: What is the conversion factor for creatinine? A: The factor is 88.42, derived from creatinine's molar mass of 113.12 g/mol. To convert mg/dL to µmol/L, multiply by 88.42. To convert µmol/L to mg/dL, divide by 88.42. Q: What is a normal serum creatinine? A: Normal serum creatinine is roughly 0.7–1.3 mg/dL (62–115 µmol/L) for men and 0.6–1.1 mg/dL (53–97 µmol/L) for women, though ranges vary by lab, muscle mass, and assay method. Q: Why is creatinine measured? A: Creatinine is a waste product cleared by the kidneys, so its blood level reflects kidney function. A rising creatinine signals reduced filtration and is used to estimate the glomerular filtration rate (eGFR). Q: Does this convert eGFR too? A: No. This tool only converts the creatinine concentration itself. eGFR is calculated from creatinine plus age, sex, and other factors using equations such as CKD-EPI, which is a separate calculation. Q: Is my data stored anywhere? A: No. The conversion runs entirely in your browser and the value you enter is never transmitted to or saved on any server. #### 24-Hour Fluid Balance Calculator URL: https://geratools.com/fluid-balance-calculator Tally all 24-hour fluid inputs (IV, oral, medications, blood) and outputs (urine, drains, NG, stool) plus an estimated insensible loss to get a net fluid balance. Built for ward nurses and ICU teams. Runs entirely in your browser. How to use: 1. Enter all fluid inputs: Add IV fluids, oral or enteral intake, IV medication and flush volumes, and any blood products given over the 24-hour period in millilitres. 2. Enter all fluid outputs: Record urine, drain losses, nasogastric aspirate or vomit, and stool. Optionally tick insensible loss and add the patient's weight and temperature. 3. Read the net balance: The tool sums inputs and outputs and shows the net 24-hour balance, flagged as a net gain, net loss or even. FAQ: Q: How is net fluid balance calculated? A: Net fluid balance is total fluid input minus total fluid output over a period, usually 24 hours. Inputs include IV fluids, oral and enteral intake, medication and flush volumes and blood products. Outputs include urine, drains, nasogastric losses, stool and estimated insensible losses. Q: What are insensible losses? A: Insensible losses are fluid lost through the skin and breathing that cannot be directly measured. They are commonly estimated at around 0.5 mL per kilogram per hour at rest, roughly 800 to 1000 mL per day in an adult. Fever increases them by about 12 percent for every degree Celsius above 37. Q: Should I include insensible loss in the chart? A: Routine ward fluid balance charts often omit insensible losses and track only measured ins and outs. This tool lets you toggle the estimate on so you can see a more physiologically complete balance, which is especially useful in ICU, sepsis or burns where insensible losses are large. Q: Does a positive balance mean fluid overload? A: Not necessarily. A single positive balance can be appropriate during resuscitation, while cumulative positive balance over several days is more concerning for overload. Always interpret the number alongside daily weights, observations, oedema and the overall clinical picture. Q: What units does the calculator use? A: All volumes are entered in millilitres over a 24-hour period. The net result is shown in millilitres, with a plus sign for a net gain and a minus sign for a net loss. Blank fields are treated as zero so you only enter what is relevant. #### Heparin Weight-Based Dosing Protocol URL: https://geratools.com/heparin-dosing-calculator Free weight-based heparin dosing calculator. Enter patient weight and per-kg bolus and infusion rates to compute the IV bolus, starting infusion in units per hour, and pump rate in mL/hr, with optional dose caps. Runs entirely in your browser. How to use: 1. Enter the weight and rates: Type the patient weight in kg and the per-kg bolus (units/kg) and initial infusion (units/kg/hr) from your nomogram. 2. Add optional caps: Enter a maximum bolus and maximum infusion if your protocol caps doses for very heavy patients. 3. Read bolus, infusion, and pump rate: Set the bag concentration in units/mL to convert the units-per-hour order into a millilitres-per-hour pump rate. FAQ: Q: How is a weight-based heparin dose calculated? A: The bolus equals the per-kg bolus times body weight, and the initial infusion equals the per-kg rate times weight. A common venous thromboembolism nomogram uses an 80 units/kg bolus and an 18 units/kg/hr infusion. Q: How is the pump rate determined? A: Pump rate (mL/hr) = infusion in units per hour ÷ bag concentration in units/mL. With a typical 25,000 units in 250 mL bag (100 units/mL), an 1,440 units/hr order runs at about 14.4 mL/hr. Q: Should bolus and infusion doses be capped? A: Many protocols cap the bolus around 10,000 units and the infusion rate for very heavy patients to limit bleeding risk. Enter your protocol caps in the optional fields and the tool clamps the calculated dose, marking it as capped. Q: How is the heparin infusion adjusted? A: The infusion is titrated to a target aPTT or anti-Xa level using your institution's nomogram. Recheck the level about 6 hours after the start and after each rate change, then adjust the rate up or down accordingly. Q: Which weight should I use? A: Most venous thromboembolism protocols use actual body weight, though some cap dosing weight in extreme obesity. Follow your institution's nomogram for the exact weight definition and any maximum dosing weight. #### Holliday-Segar Fluid Maintenance Calculator URL: https://geratools.com/holliday-segar-fluid-maintenance Applies the 4-2-1 rule (Holliday-Segar method) to patient weight to calculate daily and hourly maintenance fluid requirements in children and adults. Built for paediatric nurses, ED clinicians, and anaesthetists. Runs 100% in your browser. How to use: 1. Enter the patient's weight: Type the body weight in kilograms. The method is weight-based and applies from infants through adults. 2. Read the hourly rate: The 4-2-1 rule gives the hourly maintenance rate in mL/h, shown alongside the daily 100-50-20 total. 3. Use as a starting point: Treat the result as a baseline maintenance rate, then adjust for fever, losses, or fluid restriction as clinically indicated. FAQ: Q: What is the 4-2-1 rule? A: The 4-2-1 rule gives the hourly maintenance fluid rate: 4 mL/kg/h for the first 10 kg of body weight, 2 mL/kg/h for the next 10 kg, and 1 mL/kg/h for every kilogram above 20 kg. The three parts are added together. Q: How does the 4-2-1 rule relate to the daily 100-50-20 method? A: They are the same method expressed differently. The daily version uses 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10 kg, and 20 mL/kg beyond 20 kg. Dividing the daily total by 24 gives approximately the 4-2-1 hourly rate. Q: Does this account for ongoing losses or dehydration? A: No. Holliday-Segar estimates baseline maintenance only. Deficits from dehydration, ongoing losses (vomiting, diarrhoea, drains), and increased needs from fever must be calculated and added separately. Q: Is there an upper weight limit? A: The formula is most validated in children. In larger adults the calculated rate is often capped (commonly around 100–120 mL/h) and individualised, because pure weight scaling can overestimate needs in heavy adults. Q: Is my data stored anywhere? A: No. The calculation runs entirely in your browser and the weight you enter is never transmitted or saved on any server. #### Oral Rehydration Solution Dosing Calculator URL: https://geratools.com/rehydration-ors-calculator Computes the oral rehydration solution volume to give over four hours using WHO (75 mL/kg for some dehydration) and NICE (50 mL/kg deficit plus maintenance) protocols, from a child's weight and dehydration grade. Runs in your browser. How to use: 1. Enter the child's weight: Type the body weight in kilograms; this drives every rehydration volume in the calculation. 2. Choose protocol and dehydration grade: Pick the WHO plan B or the NICE deficit-plus-maintenance approach, then select the assessed degree of dehydration. 3. Read the volumes: The tool returns the total replacement volume over four hours and an approximate hourly rate to guide frequent small-volume feeding. FAQ: Q: How does the WHO Plan B dose work? A: The WHO treatment Plan B for some (mild to moderate) dehydration gives approximately 75 mL of ORS per kilogram of body weight over the first four hours. The calculator multiplies weight by 75 and divides the total over four hours to give an hourly target, offered in frequent small sips. Q: How is the NICE approach different? A: NICE estimates a fluid deficit of 50 mL/kg for clinical dehydration and replaces it over four hours, given on top of normal maintenance fluids. This calculator shows the deficit volume and, when maintenance is included, adds the Holliday-Segar maintenance requirement so you see the full target. Q: What is the Holliday-Segar maintenance rule? A: Daily maintenance fluid is 100 mL/kg for the first 10 kg, plus 50 mL/kg for the next 10 kg, plus 20 mL/kg for each kilogram above 20 kg. The four-hour share is one sixth of that daily figure, which the NICE-plus-maintenance option adds to the deficit. Q: When is oral rehydration not appropriate? A: Oral rehydration is unsuitable for severe dehydration or shock, persistent vomiting that prevents intake, ileus, or reduced consciousness, all of which need intravenous fluids and urgent assessment. ORS is for mild to moderate dehydration in a child who can drink. Q: Is this calculator a prescription? A: No. It reproduces published WHO and NICE volume rules for education and bedside cross-checking. Actual fluid management depends on ongoing losses, clinical reassessment, and the responsible clinician's judgement, and should follow local paediatric guidance. #### TBSA Burn Calculator (Rule of Nines & Lund-Browder) URL: https://geratools.com/tbsa-burn-calculator Calculate percent total body surface area burned using the Rule of Nines for adults or the age-adjusted Lund-Browder chart for children, then feed it straight into the Parkland fluid resuscitation formula. Runs entirely in your browser. How to use: 1. Choose a method: Select Rule of Nines for adults or Lund-Browder for children. For Lund-Browder also pick the age band, which adjusts head and leg percentages. 2. Enter the percentage of each region burned: For every body region, type how much of that area is affected from 0 to 100 percent, counting only partial and full-thickness burns. 3. Read TBSA and Parkland fluids: The tool sums regional contributions into a total percent TBSA and, with the patient's weight, shows the Parkland resuscitation volume and rates. FAQ: Q: What is the Rule of Nines? A: The Rule of Nines divides the adult body into regions each worth 9 percent of total body surface area or a multiple of nine: the head and each arm are 9 percent, the front and back of the trunk are 18 percent each, each leg is 18 percent, and the genitalia are 1 percent, totalling 100 percent. Q: Why use Lund-Browder for children? A: Children have proportionally larger heads and smaller legs than adults, so the Rule of Nines overestimates leg burns and underestimates head burns in the young. The Lund-Browder chart adjusts the head and leg percentages by age band, making it the most accurate method, especially for infants and small children. Q: How does TBSA feed into the Parkland formula? A: The Parkland formula estimates the first 24-hour fluid requirement as 4 mL multiplied by body weight in kilograms multiplied by percent TBSA burned. Half is given in the first 8 hours from the time of injury and the remaining half over the next 16 hours, then titrated to urine output. Q: Should I count superficial sunburn-type redness? A: No. Only partial-thickness (second-degree) and full-thickness (third-degree) burns are counted towards TBSA. Superficial epidermal burns with erythema but no blistering, such as simple sunburn, are excluded because they do not drive significant fluid loss. Q: Is the palm method an alternative for small burns? A: Yes. For small or patchy burns, the patient's own palm including fingers represents roughly 1 percent of their TBSA. That estimate is handy at the bedside, but for larger burns the Rule of Nines or Lund-Browder used here is more reliable. #### Vancomycin Dosing & AUC/MIC Calculator URL: https://geratools.com/vancomycin-dosing-calculator Free vancomycin dosing calculator. Enter age, weight, sex, and serum creatinine to estimate Cockcroft-Gault creatinine clearance, a loading dose, a maintenance dose range, and a starting interval targeting AUC/MIC 400–600 per ASHP 2020. Runs in your browser. How to use: 1. Enter patient demographics: Type age, body weight in kg, and select sex, which adjusts the Cockcroft-Gault clearance estimate. 2. Enter serum creatinine: Type the serum creatinine and choose its unit; µmol/L values are converted to mg/dL automatically. 3. Read the dosing plan: The estimated creatinine clearance, loading dose, maintenance range, and suggested interval appear instantly. FAQ: Q: How is creatinine clearance estimated? A: The tool uses the Cockcroft-Gault equation: CrCl = ((140 − age) × weight) ÷ (72 × serum creatinine in mg/dL), multiplied by 0.85 for females. If creatinine is entered in µmol/L it is divided by 88.4 to convert to mg/dL first. Q: What is the vancomycin AUC target? A: The 2020 ASHP/IDSA guideline recommends AUC-guided dosing targeting an AUC/MIC ratio of 400–600 mg·h/L, assuming an MIC of 1 mg/L by broth microdilution. Trough-only monitoring is no longer the preferred approach for serious MRSA infections. Q: How are loading and maintenance doses chosen? A: A loading dose of about 25 mg/kg (range 20–35) is used for serious infections, and maintenance is 15–20 mg/kg per dose. The interval is selected from renal function, lengthening as creatinine clearance falls. Q: How is the dosing interval picked? A: As a rough guide: CrCl above 90 mL/min suggests every 8–12 hours, 50–90 every 12 hours, 20–49 every 24 hours, and below 20 every 24–48 hours dosed by levels. Confirm with measured pharmacokinetics. Q: Should I rely on this estimate alone? A: No. This is a starting estimate only. Confirm and adjust dosing with two-level pharmacokinetic sampling or Bayesian software to hit the measured AUC, round doses to the nearest 250 mg, and cap single doses around 2–3 g. #### Half-Life Calculator URL: https://geratools.com/half-life-calculator Free half-life calculator for radioactive decay. Solve for the remaining amount, elapsed time, half-life or initial amount, see the decay constant and mean lifetime, and view an exponential decay chart. Runs entirely in your browser. How to use: 1. Choose what to solve for: Pick remaining amount, elapsed time, half-life or initial amount — the calculator hides the field it is solving for. 2. Enter the three known values: Type the initial amount, remaining amount, time and half-life you do know, and choose units for time and half-life. 3. Optionally pick a known isotope: Select an isotope such as Carbon-14 or Iodine-131 to auto-fill its accepted half-life. 4. Read the result and decay curve: The headline shows the solved value plus the fraction remaining, half-lives elapsed, decay constant and mean lifetime, with an exponential decay chart below. FAQ: Q: What is the half-life formula? A: The amount remaining after time t is N = N₀ · (1/2)^(t/T), where N₀ is the starting amount and T is the half-life. Equivalently N = N₀ · e^(−λt) with decay constant λ = ln(2)/T. This calculator rearranges that single equation to solve for whichever variable you leave blank. Q: What is the decay constant and how does it relate to half-life? A: The decay constant λ is the probability per unit time that a given atom decays. It is linked to the half-life by λ = ln(2)/T, where ln(2) ≈ 0.6931. A larger λ means faster decay and a shorter half-life. Q: What is the mean lifetime? A: The mean (average) lifetime τ is the average time an atom survives before decaying: τ = T/ln(2) = 1/λ. It is always longer than the half-life — about 1.4427 times the half-life — because a few long-lived atoms pull the average up. Q: How do I find the age of a sample (carbon dating)? A: Set the calculator to solve for elapsed time, enter the original amount of the isotope as N₀, the measured amount today as N, and the half-life T (for radiocarbon dating, Carbon-14 at 5,730 years). The tool returns t = T · ln(N₀/N)/ln(2), the time since the sample stopped exchanging carbon. Q: Can I work out an unknown half-life from measurements? A: Yes. Choose to solve for half-life, then enter the initial amount, the remaining amount and the elapsed time. The half-life is T = t · ln(2)/ln(N₀/N). This is how half-lives are measured experimentally from an activity-versus-time curve. Q: Does the units choice affect the answer? A: The physics is unit-independent, but your time and half-life inputs must be consistent. The calculator converts everything to seconds internally, so you can enter a half-life in days and a time in years and still get a correct result; outputs are shown in the most readable unit. #### eGFR Calculator (CKD-EPI 2021) URL: https://geratools.com/gfr-calculator Free eGFR calculator using the 2021 CKD-EPI (race-free) equation. Enter age, sex, and serum creatinine to get your estimated glomerular filtration rate, Cockcroft-Gault creatinine clearance, and KDIGO 2022 CKD stage. Runs entirely in your browser. How to use: 1. Enter your age and biological sex: CKD-EPI 2021 uses age and sex (not race) to adjust the estimate. Use the sex recorded on your lab report. 2. Enter your serum creatinine result: Type the value from your blood test. Switch the units toggle between mg/dL and µmol/L to match your lab report — the calculator converts automatically. 3. Enter your body weight: Weight in kilograms is used only for the Cockcroft-Gault creatinine clearance comparison. It does not affect the CKD-EPI eGFR figure. 4. Read your eGFR and CKD stage: The calculator shows your eGFR in mL/min/1.73m², your Cockcroft-Gault CrCl in mL/min, and your KDIGO 2022 CKD stage on a colour-coded spectrum bar. Expand "Show calculation working" to see every step of the arithmetic. FAQ: Q: What is eGFR and why does it matter? A: eGFR (estimated glomerular filtration rate) measures how well your kidneys filter waste from the blood, expressed in mL/min per 1.73 m² of body surface area. A healthy young adult has an eGFR above 90. Values persistently below 60 for more than three months indicate chronic kidney disease (CKD), which affects drug dosing, cardiovascular risk, and long-term health planning. Q: What is the CKD-EPI 2021 equation? A: CKD-EPI 2021 is the current gold-standard equation endorsed by KDIGO, NKF, and ASN. Published by Inker et al. in NEJM 2021, it removed the race adjustment from the 2009 version. The formula is: eGFR = 142 x min(Scr/kappa, 1)^alpha x max(Scr/kappa, 1)^(-1.2) x 0.9938^Age x sex-factor. For females: kappa = 0.7, alpha = -0.241, sex-factor = 1.012. For males: kappa = 0.9, alpha = -0.302, sex-factor = 1.0. Serum creatinine is in mg/dL. Q: How is Cockcroft-Gault creatinine clearance different from CKD-EPI eGFR? A: Cockcroft-Gault (1976) estimates creatinine clearance (CrCl) in mL/min using age, weight, sex, and serum creatinine without adjusting for body surface area. It is still widely used for drug dosing calculations because most pharmacokinetic studies were validated against it. CKD-EPI eGFR is preferred for CKD diagnosis and staging. The two values can diverge in patients who are very muscular, very obese, or at extremes of body size. Q: What do the CKD stages mean? A: KDIGO 2022 defines six GFR stages. G1 (eGFR 90+) is normal or high. G2 (60-89) is mildly decreased. G3a (45-59) is mild-to-moderately decreased. G3b (30-44) is moderately-to-severely decreased. G4 (15-29) is severely decreased. G5 (below 15) indicates kidney failure. CKD requires a GFR below 60 or kidney damage persisting more than three months. If your calculated eGFR is below 60, consult your GP or nephrologist. Q: Does the 2021 equation remove race as a variable? A: Yes. The 2021 update removed the race coefficient from the 2009 equation. The previous race adjustment resulted in systematic under-diagnosis of CKD in Black individuals. The 2021 equation uses only age, sex, and serum creatinine, and performs at least as well across all racial and ethnic groups in the validation cohort. Q: Should I use mg/dL or µmol/L? A: Both are accepted. UK and European labs typically report in µmol/L; US labs report in mg/dL. Select your units and the calculator converts automatically using the factor 1 mg/dL = 88.42 µmol/L. A typical normal range is roughly 0.7-1.2 mg/dL (62-106 µmol/L) for men and 0.5-1.0 mg/dL (44-88 µmol/L) for women, though reference ranges vary by laboratory. #### MAP Calculator (Mean Arterial Pressure) URL: https://geratools.com/map-calculator Free MAP calculator. Enter your systolic and diastolic blood pressure to compute Mean Arterial Pressure using the standard clinical formula MAP = (2 x DBP + SBP) / 3. See pulse pressure, classification, and a full worked example — all in your browser. How to use: 1. Enter your systolic blood pressure: Type the top number from your blood pressure reading (e.g. 120 mmHg). Normal adult systolic range is 90-120 mmHg. 2. Enter your diastolic blood pressure: Type the bottom number from your blood pressure reading (e.g. 80 mmHg). Normal adult diastolic range is 60-80 mmHg. Diastolic must be lower than systolic. 3. Read your MAP instantly: The calculator applies the formula MAP = (2 x DBP + SBP) / 3 and displays your MAP in mmHg, along with pulse pressure and a clinical classification (normal, elevated, critically low, etc.). 4. Copy your result summary: Click "Copy result summary" to copy the blood pressure, MAP, pulse pressure, and status to your clipboard in one step. FAQ: Q: What is Mean Arterial Pressure (MAP)? A: Mean Arterial Pressure is the average arterial pressure throughout one cardiac cycle. Because the heart spends roughly two-thirds of each cycle in diastole (relaxation) and only one-third in systole (contraction), MAP is not simply the midpoint between SBP and DBP — it is weighted toward diastolic pressure. The standard clinical formula is MAP = (2 x DBP + SBP) / 3, which is equivalent to MAP = DBP + (SBP - DBP) / 3. Q: What is a normal MAP range for adults? A: A MAP between 70 and 100 mmHg is generally considered normal for a healthy resting adult. A MAP below 65 mmHg is the widely-used clinical threshold for inadequate organ perfusion (used in sepsis and shock protocols). A MAP consistently above 110 mmHg indicates hypertension. These are population-level reference values; individual targets vary by condition and are determined by a clinician. Q: Why does the MAP formula weight diastolic pressure twice? A: At a typical resting heart rate of 60-80 bpm, each cardiac cycle lasts about 0.8-1 second. Systole (the ejection phase) occupies roughly one-third of that time, while diastole occupies the remaining two-thirds. Arterial pressure therefore spends proportionally more time near the diastolic value, so MAP = (1 x SBP + 2 x DBP) / 3. At higher heart rates diastole shortens and MAP shifts closer to the simple arithmetic mean, but the (2 x DBP + SBP) / 3 formula remains the standard clinical approximation. Q: What is pulse pressure and why does it matter? A: Pulse pressure (PP) is the difference between systolic and diastolic pressure. A normal resting PP is roughly 40 mmHg (e.g. 120 - 80). A widened PP (above 60 mmHg) may indicate aortic regurgitation, atherosclerosis, or high stroke volume. A narrowed PP (below 25 mmHg) may suggest hypovolaemia, aortic stenosis, or cardiac tamponade. This calculator displays PP alongside MAP so you can assess both values together. Q: Is MAP the same as average blood pressure? A: MAP is a time-weighted average, not a simple arithmetic average. The arithmetic mean of SBP and DBP (midpoint) is (SBP + DBP) / 2, whereas MAP = (SBP + 2 x DBP) / 3. For a reading of 120/80 mmHg the arithmetic mean is 100 mmHg but the MAP is (120 + 160) / 3 = 93.3 mmHg. In clinical practice, MAP is preferred because it better reflects the perfusion pressure driving blood to organs. Q: Is this calculator medically certified? A: No. This tool is for educational and informational use only. It implements the standard MAP formula used in clinical literature, but it cannot account for individual patient conditions, measurement technique, or any clinical context. Always consult a qualified healthcare professional for interpretation of blood pressure readings and treatment decisions. #### QTc Interval Calculator URL: https://geratools.com/qtc-calculator Free QTc calculator. Enter your ECG QT interval and heart rate to get corrected QTc values by four standard formulas (Bazett, Fridericia, Framingham, Hodges) with automatic classification against AHA/ACC thresholds. 100% browser-side. How to use: 1. Enter the measured QT interval: Type the raw (uncorrected) QT interval in milliseconds, read directly from the ECG. Typical values lie between 350 ms and 450 ms. 2. Enter the heart rate: Type the patient heart rate in beats per minute. The calculator derives the RR interval as RR = 60 divided by HR. 3. Select biological sex: Choose male or female. The AHA/ACC classification thresholds differ by sex — prolonged QTc is 460 ms or above for males and 470 ms or above for females. 4. Read the four corrected values: The table shows QTc in milliseconds for Bazett, Fridericia, Framingham and Hodges, each labelled Normal, Borderline, or Prolonged against the appropriate threshold. FAQ: Q: What is the QTc interval and why does it matter? A: The QT interval on an ECG measures the total time for the ventricles to depolarise and repolarise. Because it shortens at faster heart rates, a raw QT reading is meaningless without rate correction. The corrected value (QTc) allows comparison across different heart rates and patients. A prolonged QTc is associated with torsades de pointes and sudden cardiac death, making it a critical safety parameter in drug development and clinical practice. Q: What is the Bazett formula? A: Bazett (1920) defines QTc = QT divided by the square root of RR, where both QT and RR are in seconds. It is the most widely used formula in clinical software and textbooks. Its limitation is over-correction at fast heart rates (above 90 bpm) and under-correction at slow rates, which can lead to false classifications at extremes. Q: How does Fridericia differ from Bazett? A: Fridericia (1920) uses the cube root of RR instead of the square root, giving QTc = QT divided by the cube root of RR. This produces more accurate corrections across a wider range of heart rates and is the formula recommended by the International Council for Harmonisation (ICH E14) for drug safety studies. It tends to give slightly lower QTc values than Bazett at high heart rates. Q: When should I use the Framingham or Hodges formula? A: The Framingham (1992) formula applies a linear correction and performs well within the typical clinical heart-rate range of 50–90 bpm. Hodges (1983) uses the simple linear equation QTc = QT + 1.75 multiplied by (HR minus 60) in milliseconds and is popular in European cardiology practice, particularly in Holter analysis. Both reduce the over-correction seen with Bazett at elevated rates. Q: What are the normal QTc ranges? A: Using AHA/ACC 2013 guidance, a QTc below 440 ms is normal for males and below 450 ms for females. Values of 440–459 ms (male) or 450–469 ms (female) are borderline prolonged. At or above 460 ms (male) or 470 ms (female) is considered prolonged and warrants clinical review. Different societies and drug guidelines sometimes cite slightly different cut-offs. Q: Is this tool suitable for clinical use? A: No. This calculator is strictly educational. It demonstrates the standard formulas and provides reference classifications. Diagnosing QT prolongation, assessing drug safety, or making any patient management decision requires a qualified healthcare professional interpreting the full clinical context and the original ECG tracing. #### Standard Drink Calculator URL: https://geratools.com/standard-drink-calculator Free standard drink calculator. Enter volume and ABV to see how many standard drinks a serving contains across US, UK, AU and CA definitions — plus pure ethanol grams and a weekly guideline gauge. 100% client-side. How to use: 1. Choose your country standard: Select US (14 g), UK (7.9 g / 10 mL), Australia (10 g) or Canada (13.45 g) from the dropdown — each country defines a standard drink differently. 2. Pick a common drink or enter custom details: Choose a preset such as "Regular beer 355 mL 5%" or select Custom and type any volume and ABV. 3. Set the quantity: Enter how many servings you consumed or plan to consume. 4. Read the result: The calculator shows total standard drinks, grams of pure ethanol, a weekly-guideline progress bar and — via Show all country equivalents — a cross-reference table for every country standard. FAQ: Q: What is a standard drink? A: A standard drink is a unit of measurement defined by each country to represent a fixed amount of pure ethanol. The US defines it as 14 g of ethanol; Australia uses 10 g; Canada 13.45 g; and the UK uses 10 mL (about 7.9 g). The same glass of wine may count as one US standard drink but more than one Australian standard drink. Q: How is pure ethanol calculated? A: The formula is: ethanol (g) = volume (mL) times ABV/100 times 0.789 g/mL. The figure 0.789 is the density of ethanol at room temperature. For example, a 355 mL can of 5% beer contains 355 times 0.05 times 0.789 = 14.0 g of pure ethanol — exactly one US standard drink. Q: Why do countries use different standard drink sizes? A: Each government chose a different reference size when setting its own public-health messaging. The US chose 14 g partly because it roughly matches a 12 oz (355 mL) regular beer at 5% ABV. Australia chose 10 g so the figure matches a small glass of wine. There is no international consensus; the calculator lets you compare across all four major definitions instantly. Q: How many standard drinks per week is considered low-risk? A: Guidelines vary by country and sex. The US NIAAA advises up to 14 drinks/week for men and 7 for women. UK Chief Medical Officers advise no more than 14 units for both sexes spread over 3+ days. Australia recommends no more than 10 standard drinks per week. Canada suggests no more than 15 per week for men and 10 for women. The calculator shows your session total as a percentage of the lower male/female limit for your chosen standard. Q: Does ABV printed on the label equal the real alcoholic strength? A: Broadly yes — labelling laws in the EU, UK, US and Australia require ABV to be accurate within a small tolerance (usually plus/minus 0.5%). Home-brew, craft, or unregulated drinks can vary more. For commercial products the printed ABV is a reliable input for this formula. Q: Can I use this to estimate blood alcohol content (BAC)? A: No. BAC depends on body weight, sex, metabolic rate, food intake and time — factors this calculator does not model. For a rough BAC estimate use a dedicated BAC calculator. Standard drink counts are useful for tracking alcohol consumption against guidelines, not for gauging fitness to drive. ### Health & Fitness #### BMI / BMR / TDEE Calculator URL: https://geratools.com/bmi-calculator Free BMI, BMR and TDEE calculator. Enter your height, weight, age and activity level to get your body mass index with category, basal metabolic rate (Mifflin-St Jeor) and total daily energy expenditure. Supports metric and imperial. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose metric or imperial: Select your preferred unit system. Metric uses kilograms and centimetres; imperial uses pounds and feet/inches. 2. Enter your details: Fill in your biological sex, age, height and weight. These are used only for the BMR formula — nothing leaves your browser. 3. Pick your activity level and read the results: Choose the option that best matches your weekly exercise habits. Your BMI with category, BMR and TDEE update instantly. FAQ: Q: How is BMI calculated? A: BMI = weight (kg) ÷ height (m)². The standard WHO categories are: below 18.5 Underweight, 18.5–24.9 Healthy weight, 25–29.9 Overweight, 30 and above Obese. BMI is a screening tool and does not diagnose body fatness or health on its own. Q: What is the difference between BMR and TDEE? A: BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic functions. TDEE (Total Daily Energy Expenditure) multiplies BMR by an activity factor to estimate how many calories you actually burn each day. This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate for most adults: Male: 10×kg + 6.25×cm − 5×age + 5. Female: 10×kg + 6.25×cm − 5×age − 161. Q: Is my health data private? A: Yes, completely. All calculations happen inside your browser using JavaScript. No data is stored or transmitted anywhere — not even anonymously. Q: What is a healthy BMI range? A: A BMI between 18.5 and 24.9 is classed as healthy weight by the WHO. Below 18.5 is underweight and 25 or above is overweight. For a 175 cm (5 ft 9 in) adult, a healthy weight is roughly 57–76 kg (125–168 lb). Q: Does BMI work for athletes and muscular people? A: Not well. BMI uses only height and weight, so it cannot tell muscle from fat. Very muscular people often score as overweight despite low body fat. For body composition, use the body fat or waist-to-height calculator instead. Q: Why does the calculator ask for my age and sex if BMI does not use them? A: Age and sex are not part of the BMI formula, but they are needed for the BMR and TDEE figures shown alongside it. The Mifflin-St Jeor equation subtracts 5 per year of age and differs by sex (+5 for men, −161 for women). Q: How many calories should I eat to lose or gain weight? A: Start from your TDEE (maintenance). To lose weight, eat below it — a 500 kcal/day deficit yields roughly 0.45 kg (1 lb) of fat loss per week. To gain, eat 300–500 kcal above TDEE. Use the calorie deficit calculator for a precise target. #### Aquarium Protein Skimmer Sizing Calculator URL: https://geratools.com/aquarium-protein-skimmer-sizing Enter tank volume and stocking density (light, moderate, heavy, or reef) to compute the effective rated skimmer volume you need after applying a bioload correction factor. For marine and reef aquarists choosing a skimmer. How to use: 1. Enter your total system volume: Add display, sump, and refugium volume together and enter the total, since the skimmer processes the whole system. 2. Choose your stocking density: Select light, moderate, heavy, or reef to set the bioload correction factor that scales the skimmer rating up for dirtier systems. 3. Read the recommended rating: The tool multiplies your volume by the bioload factor to give the minimum rated volume a skimmer should be advertised for. FAQ: Q: Why oversize a skimmer for bioload? A: Manufacturer ratings assume an average load. A heavily stocked fish tank or coral-dense reef produces far more dissolved organics, so you apply a correction factor and pick a skimmer rated for more water than you actually have. This keeps it from being overwhelmed. Q: What correction factors does this use? A: Light planted or sparsely stocked systems use about 1.0, moderate community tanks about 1.5, heavily stocked fish systems about 2.0, and dense reef or SPS tanks about 2.5. These reflect the common reef-keeping rule of rating a skimmer for roughly twice your water volume. Q: Should I include the sump volume? A: Yes. The skimmer treats the entire connected water column. Add the display, sump, and any refugium together. Subtract for large rock and sand displacement only if you want a tighter estimate, but the total water volume is the safe input. Q: Is a bigger skimmer always better? A: Within reason, a slightly oversized skimmer gives headroom and runs more stably than one at its limit. Very oversized skimmers can be hard to tune on a lightly stocked tank and may strip the water more than needed, so match the rating to your real load. Q: Does this replace water changes? A: No. A skimmer removes dissolved organics before they break down but does not remove nitrate, phosphate buildup, or replenish trace elements. It works alongside regular water changes and other filtration, not instead of them. #### Beer Calories & Carbs Calculator URL: https://geratools.com/beer-calories-carbs Uses the standard ASBC formulas to compute calories from alcohol and residual extract, plus estimated carbohydrates per serving, from original and final gravity. Useful for homebrewers tracking nutritional content. How to use: 1. Enter original gravity: Enter the original gravity (OG) reading taken before fermentation, such as 1.050. 2. Enter final gravity: Enter the final gravity (FG) reading taken after fermentation completes, such as 1.010. The difference drives alcohol and calorie content. 3. Choose a serving size: Pick 12 oz, a pint, 330 mL, or 500 mL. The tool scales calories and carbs to the serving and also shows ABV. FAQ: Q: How are beer calories calculated? A: The ASBC formula splits calories into two parts: from alcohol = 1881.22 × FG × (OG − FG) ÷ (1.775 − OG), and from residual carbohydrates = 3550 × FG × ((0.1808 × OG) + (0.8192 × FG) − 1.0004). Adding them gives calories per 12 oz, which is then scaled to your serving. Q: Where do the carbohydrate grams come from? A: Residual carbohydrate is estimated as real extract remaining after fermentation. A common approximation is carbs (g per 12 oz) ≈ 3550 × FG × (real_extract%) ÷ 100 expressed in grams, derived from the same extract terms used for calories. It is an estimate, not a lab assay. Q: Why do two beers with the same ABV differ in calories? A: Calories come from both alcohol and leftover sugar. A dry beer (low FG) ferments more sugar to alcohol, leaving fewer carb calories, while a sweeter beer (high FG) keeps more residual extract. Same ABV, different total calories and carbs. Q: How accurate is the estimate? A: The ASBC formulas are the industry standard and are quite accurate for typical beers. They assume normal attenuation and no added post-fermentation sugar. Adjuncts, lactose, or priming sugar will shift the real figures somewhat. Q: Does this work for low-carb or session beers? A: Yes. Enter the actual OG and FG. Very dry beers (FG near 1.000) show low residual carbs, and low-OG session beers show low total calories. The same formula handles the full range from light lagers to imperial stouts. #### Bellows & Extension Tube Exposure Calculator URL: https://geratools.com/bellows-macro-extension Free bellows and extension tube calculator for macro photography. Enter your lens focal length and the extension added to get the magnification ratio, effective aperture, and exposure compensation in stops. Prevents underexposed close-up shots. Runs entirely in your browser. How to use: 1. Enter the lens focal length: Type the focal length of the lens you are using on the bellows or tubes, in millimetres. 2. Enter the extension added: Add up the lengths of all stacked extension tubes, or read the bellows draw, and enter the total in millimetres. 3. Read the compensation: The calculator shows the magnification, effective aperture, and the extra stops of exposure you need to add. FAQ: Q: How does extension affect magnification? A: Magnification from added extension equals the extension divided by the focal length. Adding 25 mm of tubes to a 50 mm lens gives a magnification of 25 ÷ 50 = 0.5×, or a 1:2 reproduction ratio. More extension on a shorter lens yields higher magnification. Q: Why do I lose light when adding extension? A: Moving the lens farther from the sensor spreads the same light over a larger image circle, so less reaches each point on the sensor. This is the bellows extension factor, and it grows with magnification, which is why close-up macro shots can need two or more extra stops of exposure. Q: How is the exposure compensation calculated? A: The light-loss factor is (magnification + 1) squared, and the compensation in stops is the base-2 logarithm of that factor, or 2 × log₂(magnification + 1). At 1× magnification the factor is 4, which is exactly two stops of extra exposure needed. Q: What is effective aperture in macro work? A: Effective aperture is the marked f-number multiplied by (magnification + 1). At 1× magnification a lens set to f/8 behaves like f/16 for both exposure and diffraction. This is why deep macro shots need careful aperture choice to balance depth of field against diffraction softening. Q: Does my camera's TTL meter already correct for this? A: Yes. Through-the-lens metering reads the light actually reaching the sensor, so it automatically compensates for extension loss. The calculation matters most with handheld light meters, flash guide numbers, or fully manual exposure, where nothing measures the light at the sensor for you. #### Spaced Repetition Review Interval Calculator URL: https://geratools.com/flashcard-review-interval-calculator Enter a card's ease factor and last review interval to compute the next review date using the SM-2 spaced repetition algorithm — the same formula used by Anki. How to use: 1. Enter the card state: Type the repetition number, current ease factor, and the last interval in days for the card you just reviewed. 2. Rate your recall: Pick the quality of your answer from 0 (blackout) to 5 (perfect), matching how the SM-2 algorithm grades each review. 3. Read the next interval: The tool applies the SM-2 update rules to give the new ease factor and the number of days until the card is due again. FAQ: Q: What is the SM-2 algorithm? A: SM-2 is the spaced repetition algorithm designed by Piotr Wozniak for SuperMemo in 1987, and it is the basis of Anki's default scheduler. It schedules each flashcard review at an expanding interval so you revise just before you would forget. Q: How is the ease factor updated? A: After each review the ease factor changes by EF + (0.1 - (5 - q) * (0.08 + (5 - q) * 0.02)), where q is your recall quality from 0 to 5. The ease factor never drops below 1.3 to keep intervals from collapsing. Q: What happens when I fail a card? A: If your recall quality is below 3 the repetition count resets to zero and the interval returns to 1 day, so the card is shown again the next day. The ease factor is still adjusted downward to reflect the difficulty. Q: How are the first intervals chosen? A: In SM-2 the first successful review schedules the card 1 day out, the second review 6 days out, and from the third review onward the interval is the previous interval multiplied by the ease factor. Q: Why is my interval not exactly previous times ease? A: Intervals are rounded to whole days, and for the first two repetitions SM-2 uses the fixed values of 1 and 6 days rather than the multiplication rule, so early intervals follow the schedule rather than pure multiplication. #### Lean Body Weight Calculator (Janmahasatian) URL: https://geratools.com/lean-body-weight Estimate lean body weight with the Janmahasatian formula, the modern equation preferred over the older James equation for obese patients. Useful for dosing remifentanil, propofol and other drugs scaled to fat-free mass. How to use: 1. Select sex: Choose male or female. The Janmahasatian equation uses different constants for each because body composition differs by sex. 2. Enter height and total weight: Type the patient's height in centimetres and their actual total body weight in kilograms. Both must be positive. 3. Read lean body weight: The tool computes BMI, then applies the Janmahasatian formula to return lean body weight in kilograms along with estimated fat mass and the fat-free fraction. FAQ: Q: What is the Janmahasatian formula? A: It is a 2005 equation that estimates lean body weight from total weight, height and sex by first calculating BMI. For men LBW equals 9270 times weight divided by 6680 plus 216 times BMI; for women the constants are 8780 and 244. The result is in kilograms. Q: Why prefer it over the James equation? A: The older James equation can paradoxically decrease as body weight rises into the severely obese range, which risks underdosing. The Janmahasatian equation increases smoothly with weight, so it gives safer, more sensible lean body weight estimates in obese patients. Q: Which drugs are dosed on lean body weight? A: Lean body weight is used for several anaesthetic and other agents, including remifentanil and the maintenance phase of propofol, where total body weight would overestimate the dose in an obese patient. Always check the specific drug's recommended dosing weight. Q: Is lean body weight the same as ideal body weight? A: No. Ideal body weight is a height-based target derived from population norms, while lean body weight is an estimate of the patient's actual fat-free mass given their current weight. The two often differ, especially in muscular or obese individuals. Q: Does this replace clinical judgement or a pharmacist check? A: No. It reproduces a published equation but does not know the drug, the indication, or the patient's organ function. Use it as an input and confirm every dose against current prescribing references and, where needed, a pharmacist. #### Close-Up Lens Diopter Calculator URL: https://geratools.com/lens-diopter-macro Compute the magnification ratio and new minimum focus distance when adding a close-up diopter filter to a lens. Supports stacking multiple diopters and varying the base lens focus distance for macro and close-up photography planning. How to use: 1. Enter the lens focal length: Type your lens focal length in millimetres. Longer lenses gain more magnification from the same diopter. 2. Add the diopter power: Enter the close-up filter strength in diopters, such as +1, +2, +4 or +10. Stacked filters simply add their powers together. 3. Read magnification and focus: The tool returns the new working magnification, the new minimum focus distance from the filter, and the maximum focus distance now possible. FAQ: Q: How does a close-up diopter add magnification? A: A close-up filter is a positive lens with a focal length in millimetres equal to 1000 divided by its diopter power. Placed in front of the main lens it lets the camera focus much closer, and the magnification gained at infinity focus equals the lens focal length times the diopter power divided by 1000. Q: How do I stack multiple diopters? A: Diopter powers add directly. A +2 and a +4 stacked behave like a single +6 filter. Always put the strongest diopter closest to the lens to minimise aberrations, and expect some loss of edge sharpness with strong stacks. Q: What is the new working distance? A: When the prime lens is set to infinity, the subject in focus sits at the diopter focal length, which is 1000 divided by the total diopter power. A +4 filter focuses at 250 millimetres; a +10 filter focuses at just 100 millimetres from the filter. Q: Why is there a near and far focus limit? A: The lens can still rack its own focus. At infinity setting the subject is at the diopter focal length, the far limit. At the lens minimum focus setting the subject is closer, the near limit. The diopter shifts the entire focus range nearer, giving a usable working band rather than a single distance. Q: Do close-up filters lose any light? A: Unlike extension tubes, close-up diopter filters cause no light loss because they do not increase the lens-to-sensor distance. This makes them attractive for handheld macro, though high-power single-element diopters can soften corners and add chromatic aberration. #### Macro Lens Working Distance Calculator URL: https://geratools.com/lens-working-distance Derives working distance (front element to subject) from focal length, minimum focus distance, and magnification for macro photography. Helps choose lenses that leave enough room for lighting and avoid scaring skittish subjects. How to use: 1. Enter focal length and magnification: Type the lens focal length in millimetres and the magnification you want to shoot at (1.0 means life-size, 1:1). 2. Add lens geometry: Enter the lens physical length (mount face to front element) so the tool can subtract it from subject distance to give true working distance. 3. Read the working distance: The result shows the gap between the front element and the subject, plus the total subject-to-sensor distance, in centimetres and inches. FAQ: Q: What is working distance in macro photography? A: Working distance is the clear gap between the front of the lens and the subject when in focus. It is shorter than the minimum focus distance, because the latter is measured from the sensor plane, not the front element. More working distance gives room for lights, diffusers, and skittish insects. Q: How is working distance calculated from magnification? A: For a thin lens, subject-to-lens distance equals the focal length multiplied by (1 + 1/magnification). At 1:1 (m = 1) that is twice the focal length. The tool then subtracts the physical lens length to estimate the front-element-to-subject gap. Q: Why does a longer focal length give more working distance? A: Subject distance scales directly with focal length: at 1:1 a 100mm lens sits about 200mm from the subject while a 60mm lens sits about 120mm away. Longer macro lenses (105mm, 150mm, 180mm) are favoured for insects precisely because they buy working distance. Q: Is this exact for real lenses? A: It uses the thin-lens approximation. Real macro lenses use internal focusing and floating elements, so true working distance can differ by a centimetre or two. Treat the result as a close planning estimate, not a laboratory figure. Q: What magnification do I enter for half life-size? A: Enter 0.5 for 1:2 (half life-size), 1.0 for 1:1 (life-size), and 2.0 for 2:1 (twice life-size). Larger magnification means the subject sits closer and working distance shrinks. #### Cardiovascular Lipid Risk Calculator (Framingham) URL: https://geratools.com/lipoprotein-fractions-risk Calculates Framingham 10-year cardiovascular risk from total cholesterol, HDL, blood pressure, age, sex, diabetes, and smoking status using the published D'Agostino 2008 general CVD model, with treatment-threshold guidance. For GPs and preventive cardiologists. How to use: 1. Enter age, sex, and lipids: Select sex, enter age between 30 and 79, and type total cholesterol and HDL in mg/dL. 2. Add blood pressure and risk factors: Enter systolic blood pressure, tick whether it is treated, and flag current smoking and diabetes. 3. Read the 10-year risk: The tool applies the Framingham Cox model and returns the percentage 10-year risk along with the low, intermediate, or high risk band. FAQ: Q: Which Framingham model does this use? A: It uses the D'Agostino 2008 general cardiovascular disease model published in Circulation, which predicts a composite of coronary heart disease, stroke, peripheral artery disease and heart failure over ten years. It uses total cholesterol and HDL rather than the older coronary-only point scores. Q: What units does it expect? A: Cholesterol values are in milligrams per decilitre. If your laboratory reports in millimoles per litre, multiply the cholesterol figure by 38.67 to convert. Blood pressure is the systolic value in mmHg. Q: What do the risk bands mean? A: Below 10 percent is generally considered low risk, 10 to 19 percent is intermediate, and 20 percent or more is high. A result of 10 percent or above usually prompts a conversation about statin therapy and lifestyle change, though local guidelines set their own thresholds. Q: Who is this calculator valid for? A: It is for adults aged 30 to 79 without established cardiovascular disease, diabetes treated as a coronary risk equivalent, or familial hypercholesterolaemia. Outside that age range, or for secondary prevention, the model does not apply. Q: Should this replace tools like QRISK or the pooled-cohort equations? A: Not necessarily. Many regions prefer QRISK3 or the ACC/AHA pooled-cohort equations, which include extra factors such as ethnicity and deprivation. Use whichever tool your local guideline specifies. This calculator is educational and not a substitute for clinical assessment. #### Macro Focus Stacking Step Calculator URL: https://geratools.com/macro-focus-stacking-interval Determine the focus-bracket step in mm needed to fully cover a subject's depth in macro focus stacking, from your magnification ratio, aperture, and circle of confusion. Outputs the per-frame depth of field and total frame count. Built for macro photographers. Runs 100% in your browser. How to use: 1. Enter your magnification: Type the magnification ratio, where 1 means 1:1 (life-size) and 2 means 2:1. 2. Set aperture and subject depth: Enter your working f-number and the total depth of the subject you want in focus, in millimetres. 3. Read the step and frame count: The tool gives the focus step between frames and how many frames cover the full depth at your chosen overlap. FAQ: Q: How is depth of field calculated at macro magnification? A: The calculator uses the macro DOF approximation DOF ≈ 2·c·N·(m+1) ÷ m², where c is the circle of confusion, N is the f-number, and m is the magnification. At high magnification the m² term makes DOF shrink dramatically. Q: How big should the focus step be? A: Slightly smaller than the per-frame depth of field, so neighbouring slices overlap. The step equals DOF × (1 − overlap). A 25–35% overlap is a safe starting point for clean stacks. Q: What circle of confusion should I use? A: Around 0.030 mm for full-frame, 0.020 mm for APS-C, and 0.015 mm for Micro Four Thirds are common defaults. Smaller values give finer steps and sharper stacks at the cost of more frames. Q: Why does higher magnification need so many frames? A: Depth of field falls roughly with the square of magnification, so doubling magnification cuts DOF to about a quarter. Covering the same subject depth then needs many more, finely spaced frames. Q: Does diffraction affect my choice of aperture? A: Yes. Stopping down increases DOF per frame but at high magnification the effective aperture grows and diffraction softens detail. Many macro shooters use f/4–f/8 and rely on more frames rather than a very small aperture. #### BCA / Bradford Protein Assay Standard Curve Calculator URL: https://geratools.com/protein-bca-bradford-curve Accepts BSA standard absorbance values at known protein concentrations, fits an ordinary least squares linear regression with an R-squared quality check, and interpolates unknown sample concentrations. For biochemistry labs quantifying protein before SDS-PAGE or western blot. How to use: 1. Enter your BSA standards: Type one standard per line as concentration then absorbance, covering the range from blank to your top standard. 2. Enter the unknown absorbances: List the measured absorbances of your samples, separated by commas or spaces. 3. Read the fitted curve and results: The tool fits a line through the standards, reports the equation and R-squared, and back-calculates each unknown concentration. FAQ: Q: Which regression does this use? A: It fits an ordinary least squares straight line, absorbance equals slope times concentration plus intercept, through your standard points. This linear model is the standard approach for the working range of both BCA and Bradford assays. Q: How are unknown concentrations calculated? A: Once the line is fitted, each unknown concentration is found by rearranging the equation: concentration equals absorbance minus the intercept, divided by the slope. The tool flags any result that falls below the curve as out of range. Q: What does R-squared tell me? A: R-squared measures how well the line fits your standards, where 1.0 is a perfect fit. A good protein standard curve usually reaches 0.99 or better. A lower value suggests pipetting error, a bad blank, or absorbances outside the linear range. Q: What if a sample reads above my top standard? A: Do not extrapolate beyond the highest standard, because both assays curve at high absorbance. Dilute the sample, re-read it within the standard range, and multiply the result back by the dilution factor. Q: Does BCA or Bradford change the maths? A: The fitting maths is identical. The chemistries differ in their useful range and linearity, so you choose the standards and read window appropriate to the kit, but the standard curve is fitted and inverted the same way for both. #### Protein Yield & Recovery Calculator URL: https://geratools.com/protein-yield-calculator Build a protein purification table from fraction volumes, protein concentrations, and enzyme activity. Computes total units, specific activity, yield percent, and purification fold at each step. For protein biochemists. Runs in your browser. How to use: 1. Enter each fraction: For every purification step add a row with its volume, protein concentration, and measured enzyme activity per millilitre. 2. Add as many steps as you need: Add rows in the order the steps were performed, starting from the crude extract, which becomes the reference for yield and fold. 3. Read the purification table: The tool computes total protein, total units, specific activity, percent yield, and purification fold relative to the first row. FAQ: Q: How is specific activity calculated? A: Specific activity is total enzyme units divided by total protein in milligrams, giving units per milligram. It measures purity: as contaminating proteins are removed, the same activity is carried by less protein, so specific activity rises. Q: What does purification fold mean? A: Purification fold is the specific activity of a step divided by the specific activity of the starting crude extract. A 10-fold value means the enzyme is ten times purer than where you began, regardless of how much total activity was lost. Q: How is percent yield defined? A: Percent yield is the total units recovered in a step divided by the total units in the crude extract, times 100. It tracks how much of your active enzyme survived purification. Yield falls at every step while fold should rise. Q: What units should I enter? A: Volume in millilitres, protein concentration in milligrams per millilitre, and activity in units per millilitre. As long as you stay consistent the table is correct. Total protein is volume times concentration and total units is volume times activity. Q: Why does my fold rise while yield falls? A: That is the normal and desired pattern. Each step discards contaminating protein, so purity (fold) climbs, but some target enzyme is inevitably lost too, so recovery (yield) drops. A good purification maximises fold while keeping yield acceptable. #### Rowing Ergometer Calorie Calculator URL: https://geratools.com/rowing-calories-calculator Enter your 500m split time and session duration to calculate calories burned using the Concept2 PM5 formula based on power output — the same algorithm the official erg monitor uses to display calories. How to use: 1. Enter your 500m split: Type the average pace your monitor shows per 500 metres, in minutes and seconds. 2. Enter session duration: Add how long you rowed at that split, in minutes. 3. Read calories and power: The tool computes the average watts from your split and converts it to calories using the Concept2 formula. FAQ: Q: What formula does Concept2 use for calories? A: Concept2 derives power in watts from your pace, then converts it with the relation Cal/hour = (4 × watts) + 300. The +300 represents the energy you would burn at rest, so even a very light row registers some calories per hour. Q: How is power calculated from my split? A: The PM monitor uses power = 2.80 / pace³, where pace is the time in seconds to cover one metre (your 500m split time divided by 500). A faster split means a smaller pace value and a much larger power figure because of the cube relationship. Q: Why are erg calories higher than my heart-rate monitor's? A: The Concept2 figure includes the resting energy you would burn anyway (the +300 term), so it tends to read higher than devices that estimate only the calories above rest. Neither is wrong; they measure slightly different things. Q: Does bodyweight change the erg calorie reading? A: No. The Concept2 calorie display is based purely on mechanical power and is independent of bodyweight, so two rowers holding the same split see the same calories. Real metabolic cost varies with weight, but the machine standardises on power. Q: Why does halving my split more than double the calories? A: Because power scales with the cube of speed. A small improvement in pace produces a large jump in watts, so calories rise steeply as you row faster. This is why short, fast pieces feel so much harder than the split difference suggests. #### BMR Calculator URL: https://geratools.com/bmr-calculator Free BMR calculator using the Mifflin-St Jeor equation — find how many calories your body burns at rest from your sex, age, height and weight. Runs entirely in your browser, nothing is uploaded. How to use: 1. Choose units and sex: Pick metric or imperial units and select your sex. 2. Enter age, height and weight: Type in your age and body measurements in the chosen units. 3. Read your BMR: Your Basal Metabolic Rate in calories per day appears instantly below. FAQ: Q: What is BMR? A: Basal Metabolic Rate is the number of calories your body burns at complete rest to keep basic functions like breathing, circulation and cell repair running. It does not include any activity. Q: Which formula does this use? A: The Mifflin-St Jeor equation, widely regarded as the most accurate predictive BMR formula for the general population. For men it is 10×kg + 6.25×cm − 5×age + 5; for women the final term is −161. Q: Is my data uploaded anywhere? A: No. Every calculation runs entirely in your browser and nothing is sent to a server or stored. Q: What is the difference between BMR and TDEE? A: BMR is calories burned at complete rest. TDEE is BMR multiplied by an activity factor (1.2 to 1.9) to include daily movement and exercise. BMR is always the smaller of the two and forms the base of every calorie target. Q: Why is BMR lower for women than men? A: The Mifflin-St Jeor equation ends with +5 for men and −161 for women, a 166 kcal gap reflecting the higher average lean body mass and lower body-fat percentage in men. Muscle is more metabolically active than fat. Q: Does BMR decrease with age? A: Yes. The formula subtracts 5 kcal for every year of age, so an otherwise identical 50-year-old has a BMR about 100 kcal lower than a 30-year-old. Loss of muscle mass over time also lowers real-world metabolism. Q: Is BMR the same as RMR? A: Almost. Resting Metabolic Rate (RMR) is measured under slightly less strict conditions than true BMR and tends to be a few percent higher, but the two are used interchangeably for everyday calorie planning. #### TDEE Calculator URL: https://geratools.com/tdee-calculator Free TDEE calculator — estimate your Total Daily Energy Expenditure from your Mifflin-St Jeor BMR and activity level, with cutting and bulking targets. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter your details: Choose units and sex, then enter your age, height and weight. 2. Pick your activity level: Select how active you are, from sedentary to extra active. 3. Read your TDEE: Your maintenance calories appear instantly, along with cutting and bulking targets. FAQ: Q: What is TDEE? A: Total Daily Energy Expenditure is the total number of calories you burn in a day, including your resting metabolism plus all movement and exercise. It is your maintenance calorie level. Q: How is TDEE calculated? A: We compute your BMR with the Mifflin-St Jeor equation, then multiply by an activity factor — 1.2 (sedentary) up to 1.9 (extra active) — to get your TDEE. Q: Is anything sent to a server? A: No. The calculation runs entirely in your browser and none of your inputs are uploaded or stored. Q: Which activity level should I choose? A: Pick the one that matches your average week, not your best week. Desk job with no exercise is sedentary (1.2). Most people who train 3–5 times a week land on moderate (1.55). Choosing too high is the most common reason a TDEE estimate overshoots. Q: How do I use TDEE to cut or bulk? A: Eat at TDEE to maintain. Subtract about 500 kcal/day to lose roughly 0.45 kg (1 lb) of fat per week, or add 300–500 kcal/day to gain lean mass. The tool shows quick −500 and +500 targets next to your maintenance number. Q: Why does my smartwatch show a different number? A: Wearables estimate calories from heart rate and movement, which captures day-to-day variation a formula cannot. The Mifflin-St Jeor + activity-factor method gives a stable planning baseline; treat a 5–10% gap between the two as normal. Q: How accurate is the activity-factor method? A: It is an estimate, typically within 10–15% for most people. The biggest source of error is overstating activity. Track your weight for 2–3 weeks at the predicted maintenance and adjust by 100–200 kcal if it drifts. #### Joules to Food Calories Converter URL: https://geratools.com/joules-to-calories-food Free joules to food Calories converter. Convert joules to the kilocalories shown on nutrition labels, or food Calories back to joules, using 1 kcal = 4184 J. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a direction: Pick joules to food Calories, or food Calories to joules, from the dropdown. 2. Enter the value: Type the joule or kilocalorie figure you want to convert. 3. Read the result: The converted value appears instantly using 1 kcal = 4184 J. FAQ: Q: How many joules are in one food Calorie? A: One food Calorie equals one kilocalorie (kcal), which is 4184 joules. A nutrition-label Calorie is always a kilocalorie, even though it is written with a capital C. Q: Why is the food Calorie a kilocalorie? A: The "Calorie" on food packaging (capital C) is 1000 small calories. To avoid confusion this tool labels it Cal (kcal) and converts at 4184 J per Calorie. Q: How do I convert joules to food Calories? A: Divide the energy in joules by 4184. For example 4184 J is 1 food Calorie, and 2,092,000 J is 500 Cal. To go the other way, multiply Calories by 4184. Q: How do I convert kilojoules (kJ) to Calories? A: Multiply the joule result by 1000 first if you have kilojoules, or simply remember that 1 kJ is about 0.239 food Calories. A label showing 1046 kJ is roughly 250 Cal. Q: Is the food Calorie the same as the calorie used in physics? A: No — the food Calorie (kcal) is 1000 times the small thermochemical calorie. The small calorie is 4.184 J; the food Calorie is 4184 J. This tool uses the food Calorie. Q: How many joules are in a typical meal? A: A 600 Cal meal contains 600 × 4184 = 2,510,400 joules. Daily intakes of around 2000 Cal equal roughly 8,368,000 J, or 8368 kJ. Q: Is my data uploaded? A: No — every conversion runs in your browser and nothing is sent to any server. #### Steps to Calories Calculator URL: https://geratools.com/step-to-calories Free steps-to-calories calculator — turn your daily step count into estimated calories burned using your body weight and walking pace and MET values. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter your steps: Type how many steps you walked, for example 10,000 from your phone or fitness tracker. 2. Add weight and pace: Enter your body weight in kg or lb and pick whether you walked at a slow, moderate or brisk pace. 3. Read the calories: The calculator estimates calories burned using the activity MET value for your pace, updating instantly. FAQ: Q: How many calories does 10,000 steps burn? A: It depends mostly on your weight and pace. For a 70 kg person walking at a moderate pace, 10,000 steps burns roughly 400 calories. Heavier people and faster paces burn more. Q: How does the calculation work? A: Steps are converted to walking time using an average cadence for your pace (80, 100 or 120 steps per minute for slow, moderate or brisk). Calories are then estimated with kcal = MET × weight in kg × hours, where MET is 2.8, 3.5 or 5.0 for those paces. Q: What is a MET value? A: A MET (metabolic equivalent of task) is how many times your resting energy use an activity demands. Walking ranges from about 2.8 METs (slow) to 5.0 METs (brisk), so brisk walking burns energy faster per minute. Q: Does walking faster burn more calories for the same steps? A: Yes. A brisk pace has both a higher MET and a higher cadence, so although the same step count takes less time, the higher intensity raises the total energy burned for a given number of steps. Q: Can I enter my weight in pounds? A: Yes. Choose lb and it is converted to kilograms internally (1 lb = 0.453592 kg) before the calorie formula is applied. Q: Is my data uploaded? A: No. The calculator runs entirely in your browser and nothing is sent to a server. #### Marathon Time Predictor URL: https://geratools.com/marathon-time-predictor Free marathon time predictor. Enter a recent 5K, 10K or half-marathon result and estimate your marathon, half, 10K or 5K finish time with the Riegel formula. Runs entirely in your browser. How to use: 1. Enter a recent race time: Type the hours, minutes and seconds from a recent race you ran all-out. 2. Pick the distances: Choose the distance you actually ran and the distance you want to predict. 3. Read the prediction: The estimated finish time and average pace per kilometre appear instantly. FAQ: Q: What formula does this use? A: It uses Pete Riegel's endurance formula: T2 = T1 × (D2 / D1) ^ 1.06, where the exponent 1.06 accounts for fatigue over longer distances. Q: How accurate is the prediction? A: Riegel predictions are most reliable when the input race is recent, run at full effort, and reasonably close in distance to the target. Marathon predictions also assume you have done the appropriate endurance training. Q: Is my data sent anywhere? A: No — every calculation runs locally in your browser and nothing is uploaded. Q: Why is the exponent 1.06 and not 1? A: If pace stayed identical at every distance the exponent would be 1.0, meaning time scales linearly with distance. The exponent 1.06 is slightly larger because runners slow down over longer distances as fatigue sets in. Pete Riegel derived 1.06 from real race data; it is the standard value used for road-race prediction. Q: Can I use a 5K to predict a marathon? A: Yes, but the further apart the two distances are the more the prediction depends on your endurance base. A 5K extrapolated to a marathon (more than 8x the distance) assumes you have done marathon-specific long-run training; without it your real time will be slower than the formula suggests. Q: Does it predict shorter distances too? A: Yes. The formula works in both directions, so you can enter a half-marathon and predict a 10K or 5K equivalent. It simply rearranges to T2 = T1 × (D2 / D1) ^ 1.06 for any pair of distances. Q: What distances can I choose? A: You can convert between the four common road distances built in: marathon (42.195 km), half marathon (21.0975 km), 10 km and 5 km. Pick the one you actually raced and the one you want to predict. #### VDOT Running Calculator URL: https://geratools.com/vdot-running-calculator Free VDOT calculator. Enter a race distance and time to get your Daniels–Gilbert VDOT score — a VO2max-based running fitness number used to set training paces. Runs entirely in your browser. How to use: 1. Choose your race distance: Select the distance of the race you want to score, from 1500 m to the marathon. 2. Enter your race time: Type the hours, minutes and seconds you ran for that distance. 3. Read your VDOT: The Daniels–Gilbert VDOT score appears instantly below. FAQ: Q: What is VDOT? A: VDOT is a single fitness number from Jack Daniels' running formula. It is derived from a VO2max model: a faster race performance produces a higher VDOT, and equal VDOTs across distances represent equivalent fitness. Q: How is VDOT calculated here? A: The tool uses the Daniels–Gilbert equations. It computes VO2 = -4.60 + 0.182258·v + 0.000104·v² (v = velocity in metres per minute), then divides by the fraction of VO2max sustainable for that race duration. Q: What distances can I score? A: Anything from 1500 m, the mile, 3000 m, 5 km, 10 km and the half marathon up to the full marathon. Each is converted to its exact metre distance before the calculation. Q: Why does the same VDOT give different paces at different distances? A: A runner can hold a higher fraction of VO2max for a 5 km than a marathon. The model accounts for this, so one VDOT maps to a faster pace over short distances and a slower pace over long ones. Q: Is VDOT the same as VO2max? A: No. VO2max is a lab-measured oxygen-uptake value. VDOT is a "pseudo VO2max" inferred from race performance that bundles in running economy, so it is a practical proxy rather than a physiological measurement. Q: How do I use my VDOT score? A: It sets equivalent race times and training paces (easy, marathon, threshold, interval, repetition). A higher VDOT after a few weeks of training is direct evidence your fitness has improved. Q: Is my race data uploaded? A: No — the calculation runs entirely in your browser and nothing leaves your device. #### Heart Rate Recovery Calculator URL: https://geratools.com/heart-rate-recovery Free heart rate recovery (HRR) calculator: enter your peak heart rate and your pulse 1 or 2 minutes after stopping to see your recovery in bpm. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your peak heart rate: Type the highest heart rate you reached at the end of your workout, in beats per minute. 2. Enter your recovery heart rate: Record your pulse 1 or 2 minutes after stopping and select the matching interval. 3. Read the drop: The calculator shows how many beats per minute your heart rate fell, with a quick fitness reference. FAQ: Q: What is a good heart rate recovery? A: At one minute, a drop of 12 bpm or more is generally considered normal and 20 bpm or more is a good sign of cardiovascular fitness. A drop under 12 bpm at one minute is a recognised risk marker worth discussing with a clinician. Q: How do I calculate heart rate recovery? A: Subtract your heart rate after a fixed recovery interval from your peak heart rate at the end of exercise. For example, a peak of 170 bpm falling to 145 bpm after one minute is a recovery of 25 bpm. Q: When should I measure recovery heart rate? A: Note your peak heart rate the moment you stop hard effort, then count your pulse exactly 1 or 2 minutes later while standing or sitting still. Q: Should I cool down or stop dead to measure HRR? A: Clinical HRR tests often have you stand or sit still immediately after stopping. An active cool-down (walking) keeps the heart rate higher, so for a consistent reading use the same method each time and note which you used. Q: Does HRR differ at 1 minute versus 2 minutes? A: Yes — the heart keeps falling, so the 2-minute drop is larger. The 12/20 bpm thresholds apply to the 1-minute mark; for 2 minutes there is no single cut-off, so track your own trend over weeks. Q: Is my data stored anywhere? A: No — every calculation runs in your browser and nothing is uploaded or saved. #### Workout Log URL: https://geratools.com/workout-log A free, private workout log. Record exercises with sets, reps and weight per session, see your full training history, automatic personal-best and estimated 1RM highlights, and export to CSV or JSON. Runs entirely in your browser. How to use: 1. Set the date and unit: Pick the session date and whether you lift in kg or lb. Add your bodyweight if you want to track it. 2. Add exercises and sets: Type an exercise name (or pick a quick button), then enter reps and weight for each set. Use Add set to clone the last set. 3. Log the session: Press Log session to save it. Your history, lifetime totals and personal bests update instantly and persist in this browser. 4. Export a backup: Use Export CSV for a spreadsheet or Backup JSON to move your full log to another device. FAQ: Q: How is the estimated one-rep max calculated? A: It uses the Epley formula, estimated 1RM = weight times (1 + reps divided by 30). A 100 kg set for 5 reps estimates roughly 117 kg. It is a model, not a guarantee, so treat heavy attempts with proper warm-ups and a spotter. Q: What counts as a personal best? A: For each exercise the log tracks three bests: your heaviest single set, your highest estimated 1RM across all sets, and your biggest single-session training volume (the sum of reps multiplied by weight). The current heaviest 1RM set is highlighted in green as you type. Q: Does it handle both kilograms and pounds? A: Yes. Each session stores its own unit, and all personal bests are compared internally in kilograms, so a kg session and a lb session are ranked fairly. Bests are then shown in whichever unit your current editor is set to. Q: Is my training data private? A: Completely. Every session is stored only in your browser local storage and nothing is ever uploaded. Clearing your browser data removes it, so export a JSON backup before switching devices. Q: Can I edit or delete a past session? A: Yes. Open any session in the history list, then choose Edit to load it back into the editor or Delete to remove it. Edited sessions keep their original date and recompute your totals and bests automatically. Q: How do I move my log to a new phone or laptop? A: Press Backup JSON to download a file containing every session, then open this tool on the new device and use Import JSON to restore it. CSV export is also available for spreadsheets, but JSON is the lossless format for restoring. #### Heart Rate Zone Calculator URL: https://geratools.com/heart-rate-zone-calculator Free heart rate zone calculator. Enter your age (plus an optional resting HR for the Karvonen method) to get all five training zones with precise BPM ranges. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your age: Your age sets the estimated maximum heart rate. Pick a formula: 220 minus age (Fox), the more accurate Tanaka equation, or Gulati for women. 2. Choose a zone method: Use % of Max HR for a quick estimate, or switch to Karvonen (Heart-Rate Reserve) and add your resting pulse for personalised, more accurate zones. 3. Read your five zones: Each row shows the lower and upper BPM for that zone, the intensity percentage, and what the zone trains — from recovery in Zone 1 to VO2 max in Zone 5. FAQ: Q: How are heart rate training zones calculated? A: First the tool estimates your maximum heart rate from your age. With the % of Max method, each zone is simply a percentage band of that maximum (Zone 1 is 50-60%, Zone 5 is 90-100%). With the Karvonen method it works from your heart-rate reserve instead, so it factors in your resting pulse for a more individual result. Q: What is the Karvonen formula? A: The Karvonen formula uses your heart-rate reserve, which is maximum HR minus resting HR. A target is found with: target = resting HR + intensity x (max HR - resting HR). Because it accounts for your resting pulse, two people of the same age but different fitness get different target zones. Q: Which max heart rate formula should I use? A: The classic 220 minus age (Fox) is easy to remember but overestimates for older adults and underestimates for some younger ones. The Tanaka equation, 208 minus 0.7 x age, is more accurate across ages. Gulati, 206 minus 0.88 x age, was derived specifically for women. A measured max from a lab or field test always beats any formula. Q: What is Zone 2 and why is it popular? A: Zone 2 sits at roughly 60-70% intensity — an easy, conversational pace you can hold for a long time. It builds aerobic base, improves fat metabolism and mitochondrial density, and carries low injury and recovery cost, which is why endurance coaches prescribe large volumes of it. Q: Do I need a resting heart rate to use this? A: Only for the Karvonen method. For % of Max HR you just need your age. To measure resting HR, count your pulse for 60 seconds first thing in the morning before getting out of bed, ideally averaged over a few days. Q: Are these zones medical advice? A: No. They are estimates based on population-average formulas and are meant for general fitness planning. If you have a heart condition, are on medication that affects heart rate (such as beta-blockers), or are new to intense exercise, talk to a doctor before training by heart rate. #### Marathon Pace Predictor URL: https://geratools.com/marathon-pace-predictor Free marathon pace predictor using Jack Daniels VDOT and the Riegel formula. Enter a goal time or a recent race result to get your marathon pace, five training zones (E/M/T/I/R), negative-split strategy and a full 5-km split table. Runs entirely in your browser. How to use: 1. Choose your starting point: Pick "I have a goal marathon time" to work backwards from a finish-time target, or "I have a recent race result" to let the tool predict your marathon from a 5K, 10K or half. 2. Enter the time: Type hours, minutes and seconds into the three fields. Common targets: 3:00, 3:30, 4:00, 4:30, 5:00. 3. Read your marathon pace: The hero card shows your goal finish time, average pace per km, pace per mile and VDOT aerobic index instantly. 4. Study your training zones: The five Daniels zones (Easy, Marathon, Threshold, Interval, Repetition) appear as a pace range in both km and miles. 5. Set a negative-split strategy: Slide the negative-split slider from 0% (even pace) up to 6% to see how your first and second half paces diverge and how the 5-km split targets adjust. 6. Copy your paces: Hit "Copy pace summary" to copy a plain-text version of all zones and splits to your clipboard for your training plan or GPS watch. FAQ: Q: What is VDOT and why does it matter? A: VDOT is Jack Daniels' aerobic-index number — a surrogate for VO2max derived from race performance rather than a lab test. A 3:30 marathon corresponds to roughly VDOT 46. Once the calculator knows your VDOT it can pinpoint the exact velocity for each training zone, because each zone is defined as a percentage of the effort at which you run out of oxygen. Q: How is the marathon pace calculated from a shorter race? A: When you enter a recent race result the tool first derives your VDOT from the Daniels formula: VDOT = VO2(v) / %VO2max(t), where v is your race velocity in m/min and t is your race duration in minutes. It then solves the inverse — finding the marathon time at which that VDOT corresponds — using numerical bisection. This is more physiologically grounded than a straight Riegel extrapolation because it accounts for the diminishing oxygen utilisation at longer efforts. Q: What are the five training zones shown? A: The five zones come from Jack Daniels' Running Formula (3rd ed., 2014). Easy (E) is 59–74% VDOT effort — conversational aerobic base work that makes up most of weekly mileage. Marathon pace (M) is 75–84% — the sustained effort you can maintain for a full marathon. Threshold (T) at 83–88% is "comfortably hard," used in cruise intervals to raise lactate threshold. Interval (I) at 95–100% targets VO2max, run as 3–5 minute hard reps. Repetition (R) at 105–120% builds speed and economy with full-recovery short reps. Q: What is a negative split and how much should I aim for? A: A negative split means running the second half of a marathon faster than the first. Most elite world records are set with a 1–3% negative split — for a 3:30 marathon that means running the first half in about 1:46 and the second in about 1:44. Running the first half too conservatively wastes energy; running it too fast blows up your glycogen before 35 km. The slider lets you model any degree of split from even pace (0%) up to 6% so you can see the actual per-km targets before race day. Q: How accurate is the Riegel formula for the race equivalents table? A: Pete Riegel's formula T2 = T1 × (D2 / D1)^1.06 is accurate within about 2–4% for distances within a factor of 4 of each other — so a 10K to half prediction is very reliable, while a 5K to marathon jump (8x the distance) assumes you have done the marathon-specific long-run training to back it up. Without an adequate aerobic base your real marathon will be slower than the formula suggests. Q: Can I use this for a half marathon instead of a full marathon? A: The training zones and the race-equivalents table work for any race distance because they derive from VDOT, not from the marathon specifically. However, the 5-km split card and the negative-split slider are marathon-specific (42.195 km). Use the Running Pace Calculator Pro or the Marathon Time Predictor tools for non-marathon target distances. #### Plate Loading Calculator URL: https://geratools.com/plate-loading-calculator Free barbell plate loading calculator. Enter your target weight and bar weight, and get the exact plates to load per side — Olympic kg or US lb sets. 100% client-side. How to use: 1. Choose your unit system: Select kilograms (Olympic standard) or pounds (US standard). The plate set and default bar weight update automatically. 2. Enter the target total weight: Type the weight you want on the bar including the bar itself — for example 100 kg or 225 lb. 3. Confirm or adjust the bar weight: The default is 20 kg (44 lb) for a standard Olympic bar. Change it if you are using a women's 15 kg bar, a hex bar, or a fixed-weight bar. 4. Read the per-side plate list: The calculator shows the exact plates to load on each side in the optimal order, plus a colour-coded barbell diagram. 5. Copy the summary: Hit "Copy summary" to paste the loading scheme into your training log or share it with a training partner. FAQ: Q: How does the plate loading calculator work? A: It uses a greedy algorithm: per-side weight = (target − bar weight) / 2. Starting from the heaviest available plate, it places as many of that plate as fit, then moves down to the next denomination until the per-side weight is accounted for exactly. This matches how an experienced lifter loads a bar — largest plates closest to the sleeve collar, smallest outermost. Q: What plate denominations are included? A: The kg set mirrors the standard IWF / IPF Olympic set: 25, 20, 15, 10, 5, 2.5, 1.25, 0.5, and 0.25 kg. The lb set mirrors a standard US commercial gym: 45, 35, 25, 10, 5, 2.5, and 1.25 lb. These cover the vast majority of loading scenarios in any well-equipped gym. Q: What if my target weight is not achievable with standard plates? A: Not every kilogram or pound value can be built from standard plate denominations. If your target cannot be assembled exactly, the calculator flags the gap and suggests adjusting your target. For example, 101 kg cannot be made with a 20 kg bar and standard kg plates — 100 kg or 102.5 kg can. Q: What is the correct plate loading order on the bar? A: Always load the heaviest plate first (closest to the collar) and the lightest last. This keeps the bar balanced during loading and is the convention enforced at all sanctioned competitions. Never place a lighter plate between two heavier ones, as this creates uneven stress on the sleeve. Q: Does bar weight include collars? A: Technically no — competition collars weigh 2.5 kg (5.5 lb) each, adding 5 kg / 11 lb to the total. Most lifters omit them in training log totals. If precision matters, subtract collar weight from the bar field (e.g., enter 15 kg instead of 20 kg when using 20 kg bar + 2.5 kg collars). Q: What are the standard Olympic barbell weights? A: The most common bars are: 20 kg / 44 lb (men's Olympic bar, 2.2 m, 28–29 mm shaft), 15 kg / 33 lb (women's Olympic bar, 2.01 m, 25 mm shaft), and 20 kg / 44 lb (powerlifting bar, 2.2 m, 28–32 mm). Trap/hex bars vary from 18–34 kg depending on manufacturer — weigh yours or check the product spec before logging totals. #### Steps to Calories Calculator URL: https://geratools.com/steps-to-calories-calculator Advanced steps-to-calories calculator using MET values, height-based stride length, and the Compendium of Physical Activities formula. Enter your steps, weight, height, and pace to see calories burned, distance walked, fat burned, progress toward your step goal, and weekly / monthly / yearly projections. 100% client-side — nothing is uploaded. How to use: 1. Enter your step count: Type in the number of steps you walked today — your fitness tracker, phone, or smartwatch will have this figure. 2. Set your weight and height: Enter your body weight (kg or lb) and height (cm or ft/in). Height is used to estimate your stride length, which determines distance and refines the calorie calculation. 3. Choose your pace and step goal: Select the pace that best matches how you walked — slow, moderate, brisk, or fast. Then pick your daily step goal to see how close you are. 4. Read the results: The calculator instantly shows calories burned, distance, walking time, fat burned, goal progress bar, and projections for a week, month, and year. FAQ: Q: How does the steps-to-calories formula work? A: The calculator uses three steps. First, it converts your step count to walking time using your pace cadence (80, 100, 120, or 140 steps per minute for slow through fast). Second, it looks up the MET (metabolic equivalent of task) for your pace: 2.8 for slow, 3.5 for moderate, 5.0 for brisk, 6.3 for fast — from the 2011 Compendium of Physical Activities. Third, it applies the standard energy formula: kcal = MET x weight(kg) x hours. The result is the gross calorie burn, which is what most fitness trackers report. Q: Why does height matter for the calorie estimate? A: Height determines stride length. Taller people take longer strides, so the same step count covers a greater distance and takes slightly less time for the same speed. Stride length (m) is estimated as height(m) x a pace-and-sex-adjusted factor, based on published gait research. This makes the distance and kcal/km figures accurate for your body rather than using a population average. Q: How many calories do 10,000 steps burn? A: For a 75 kg person of average height walking at a moderate pace, 10,000 steps burns roughly 380–420 kcal. The exact figure depends on your weight (heavier people burn more), height (taller strides = different time-to-distance ratio), and pace (higher MET = more energy per minute). Use the calculator with your own numbers for a personalised estimate. Q: What is a MET value? A: MET stands for metabolic equivalent of task. A MET of 1 is the energy your body uses at rest (sitting still). Walking at a slow pace has a MET of about 2.8 — meaning it burns 2.8 times your resting energy per unit of time. Brisk walking reaches MET 5.0 and fast power-walking MET 6.3. The higher the MET, the more calories burned per minute and per step. Q: How is fat burned calculated? A: One kilogram of body fat stores approximately 7,700 kcal of energy (a widely accepted biochemistry estimate). The calculator divides your total calorie burn by 7,700 to show grams of fat burned. This is the theoretical maximum if those calories came entirely from fat — in practice the body mixes fuel sources, so treat it as a motivational guide rather than a precise measurement. Q: Does the calculator account for resting calories? A: No. The MET formula gives gross energy expenditure — it includes the calories you would have burned resting anyway. Some fitness apps subtract resting calories to show net active burn, which is slightly lower. For consistency with most wearables and the scientific literature, this calculator uses gross kcal. #### Beep Test Calculator URL: https://geratools.com/beep-test-calculator Free beep test (20m multi-stage fitness test / PACER) calculator. Enter the last level and shuttle you completed to get your estimated VO2 max using the Léger et al. 1988 formula, your total distance, and an age-and-sex fitness rating. Runs entirely in your browser. How to use: 1. Enter your age and sex: Age and biological sex are needed because the Léger formula uses age to adjust the VO2 max estimate. 2. Select your last completed level: Choose the level you were on when you failed to reach the line in time or voluntarily stopped. 3. Enter the last shuttle you finished: Within that level, type the number of the last 20 m shuttle you completed before the beep test ended for you. 4. Read your VO2 max and fitness rating: Your estimated VO2 max (ml/kg/min), fitness category, total distance covered, and approximate test duration appear instantly. FAQ: Q: What is the beep test? A: The beep test (officially the 20-Metre Multi-Stage Fitness Test, also called the bleep test or PACER) is a progressive aerobic capacity test. You run 20 m back and forth in time with audio beeps. Each level increases the running speed by 0.5 km/h, starting at 8.5 km/h at level 1. When you can no longer reach the line before the beep twice in a row, the test ends and your last level and shuttle are recorded. Q: What formula does this calculator use? A: It uses the Léger et al. (1988) regression equation: VO2max = 31.025 + 3.238v − 3.248A + 0.1536·A·v, where v is the running speed at the last completed level in km/h and A is age in years. This is the original validated formula published alongside the test protocol and is the standard used in physical education, sport science, and military fitness testing worldwide. Q: How accurate is the beep test VO2 max estimate? A: Léger et al. reported a correlation of r = 0.84 between predicted and directly measured VO2 max in the validation study. That means it is a good field estimate but not as precise as a laboratory graded exercise test with gas analysis. Motivation, pacing, and test conditions (surface, temperature, footwear) all influence your score. Q: What is a good beep test score? A: It depends heavily on age and sex. A fit 25-year-old male reaching level 12–13 (VO2 max roughly 53–56 ml/kg/min) would be rated excellent. A fit 25-year-old female reaching level 9–10 (roughly 44–47 ml/kg/min) would be excellent for her norms. Many professional footballers and rugby players score in the 13–15 range; elite endurance athletes can reach level 17 or higher. Q: How is speed determined at each level? A: The original Léger protocol sets the speed at level L as 8 + (0.5 × L) km/h. Level 1 runs at 8.5 km/h, level 2 at 9.0 km/h, and so on. The beep interval shortens at each level so that the 20 m must be covered in the shorter time. The number of shuttles per level also varies (from 7 at level 1 up to 21–24 at the highest levels) to fill a complete minute at each speed. Q: Does the calculator work for children? A: The Léger formula was validated on subjects aged 7–45, so it is applicable to school-age children. However, the fitness rating bands shown are based on adult ACSM norms. For children and adolescents the same VO2 max figure means something different; consult age-specific paediatric reference tables for a precise category. #### Cooper Test Calculator URL: https://geratools.com/cooper-test-calculator Free Cooper Test calculator. Enter the distance you ran in 12 minutes and instantly get your estimated VO2max (ml·kg⁻¹·min⁻¹), ACSM fitness category, and population percentile. Reverse mode: enter a target VO2max to find the distance you need to cover. Runs entirely in your browser — nothing is uploaded. How to use: 1. Select your sex and enter your age: Fitness norms differ by sex and age group — the calculator automatically picks the correct ACSM reference table for you. 2. Run as far as you can for exactly 12 minutes: Use a flat, measured track or a GPS watch. The standard track distance is 400 m per lap. Note the total metres (or miles) covered when the 12 minutes end. 3. Enter the distance: Type the distance in metres or switch to Imperial and enter miles. The calculator converts automatically between metres, kilometres, miles, and yards. 4. Read your VO2max and fitness category: Your estimated VO2max appears immediately along with your fitness category (Very Poor to Superior), your approximate population percentile, and — in forward mode — how far you need to run to reach the next category. 5. Use reverse mode to set a training target: Switch to VO2max → Target distance, enter a goal VO2max, and the calculator shows exactly how far you must cover in 12 minutes to hit that target. FAQ: Q: What is the Cooper Test? A: The Cooper Test (also called the Cooper 12-Minute Run Test) was developed by Dr Kenneth H. Cooper in 1968 as a simple field test of aerobic fitness for the US Air Force. The protocol is straightforward: run as far as possible in exactly 12 minutes on a flat surface. The total distance is then used to estimate maximal oxygen uptake (VO2max), the gold-standard measure of cardiorespiratory endurance. The test became one of the most widely validated and replicated fitness assessments in sports science history. Q: What is the exact Cooper Test formula? A: The original Cooper (1968) formula is VO2max = (d − 504.9) / 44.73, where d is the distance covered in metres. For example, running 2,400 m gives VO2max = (2400 − 504.9) / 44.73 = 42.3 ml·kg⁻¹·min⁻¹. The constants 504.9 and 44.73 were derived by Cooper through regression against direct laboratory VO2max measurements in a large military cohort. The calculator also supports the reverse formula: d = VO2max × 44.73 + 504.9, which tells you how far you must run to achieve a particular VO2max. Q: How accurate is the Cooper Test VO2max estimate? A: The Cooper Test is a valid and reliable *field estimate* of VO2max, not a laboratory measurement. Validation studies report correlations of r = 0.90 or higher against direct (incremental treadmill with expired gas analysis) VO2max testing. The standard error of estimate is roughly ±3–5 ml·kg⁻¹·min⁻¹. Accuracy is highest when the runner paces evenly — starting too fast and slowing (positive-split) or running conservatively (negative-split) both reduce accuracy. Factors such as extreme heat, altitude, dehydration, or surface conditions can also shift the result. Q: What is a good VO2max for my age? A: VO2max declines roughly 1% per year after age 25 in sedentary individuals, but active people retain far more capacity. As a general benchmark: a VO2max above 50 ml·kg⁻¹·min⁻¹ is excellent for men under 40; above 40 is excellent for women under 40. Elite male distance runners reach 70–85 ml·kg⁻¹·min⁻¹; elite women 60–75. The calculator classifies your result against ACSM age-and-sex-specific norms across six categories — Very Poor, Poor, Fair, Good, Excellent, and Superior — so you always see your result in the correct context for your demographic. Q: How should I prepare for the Cooper Test? A: Avoid hard training in the 24–48 hours before the test. Do a 10-minute warm-up jog and dynamic stretches beforehand. Use a measured surface — a 400 m athletics track is ideal, or a GPS watch on a flat road. Start at a comfortable aerobic pace you can sustain, aiming for even splits across all 12 minutes. Any change in pace should be gradual. Cool down with a 5-minute walk and light stretching after. The test can be repeated every 4–8 weeks to track aerobic fitness progress. Q: Can I use the Cooper Test on a treadmill? A: A treadmill test is not directly comparable to an outdoor test because treadmill belts assist leg turnover slightly, and there is no wind resistance. If you must use a treadmill, set the incline to 1–2% to partially compensate. Record the distance from the treadmill display. The VO2max estimate will still be directionally accurate and useful for tracking your own progress over time, as long as you always test under the same conditions. #### Treadmill Pace Converter URL: https://geratools.com/treadmill-pace-converter Free treadmill pace converter: translate km/h or mph into min/km or min/mile pace, see projected finish times for 5 km to marathon, and get ACSM-formula calorie burn. Runs entirely in your browser. How to use: 1. Enter your treadmill speed: Type the speed shown on your treadmill display and choose whether it is in km/h or mph. 2. Choose your preferred pace unit: Select min/km for metric or min/mile for imperial — both are shown automatically. 3. Set the incline and your weight: Enter the treadmill grade in percent (0 for flat) and your body weight to get accurate calorie figures. 4. Read pace, calories and finish times: The tool instantly shows your pace, MET, kcal per minute, and projected finish times for six standard race distances. 5. Use reference speed shortcuts: Click any labelled preset (easy jog, sub-3h marathon pace, etc.) to load that speed instantly. FAQ: Q: How do I convert treadmill speed to running pace? A: Pace (min/km) = 60 ÷ speed (km/h). For example, 10 km/h gives a pace of 6:00 min/km. For min/mile, use pace = 60 × 1.60934 ÷ speed (km/h). The tool applies these exact formulas in real time. Q: What speed is a 5-minute kilometre on the treadmill? A: A 5:00 min/km pace equals exactly 12 km/h (7.46 mph). Set your treadmill to 12.0 km/h and you are running at that pace. Q: Does treadmill incline affect pace? A: Yes. Running at 1% grade simulates outdoor running on a flat road (compensating for lack of wind resistance). Higher grades add significantly more cardiovascular load. The tool shows the flat-equivalent pace using the Daniels adjustment of roughly 20 seconds per km per 1% grade, so you can compare indoor and outdoor efforts fairly. Q: How are treadmill calories calculated? A: The tool uses the American College of Sports Medicine (ACSM) metabolic equation for running: VO₂ (mL/kg/min) = 0.2 × speed (m/min) + 0.9 × speed × grade/100 + 3.5. Dividing by 3.5 gives METs. Calories per minute = MET × 3.5 × body mass (kg) ÷ 200. This is the standard clinical formula used in exercise physiology. Q: What is a good treadmill speed for weight loss? A: Any sustained aerobic effort burns calories, but a moderate-intensity jog in the 8–10 km/h range (MET 8–10) balances fat oxidation and overall energy expenditure well for most adults. Use the calculator to find the speed that puts your heart rate in the 60–75% max zone for your goals. Q: Why does 1% incline equal outdoor running? A: Research by Jones and Doust (1996) showed that running on a treadmill at 0% grade slightly underestimates outdoor effort because there is no air resistance. Setting the treadmill to 1% grade closely matches the energy cost of running on a flat outdoor surface at the same speed — a rule that has become the standard recommendation among coaches and sport scientists. #### TDEE Calculator — Katch–McArdle & Cunningham URL: https://geratools.com/tdee-katch-mcardle-calculator Free TDEE calculator using the Katch–McArdle formula (BMR = 370 + 21.6 × LBM) and Cunningham variant. Requires body fat %, ignores height and sex for pure lean-mass accuracy. Includes calorie goal table, macro split, 12-week projection chart, and a unique solve-for-BF mode. 100% browser-side. How to use: 1. Enter your body weight: Type your total body weight in kg or lb. The calculator uses this alongside your body fat percentage to derive lean body mass. 2. Enter your body fat percentage: Use a DEXA scan, BodPod, skinfold callipers or a recent bioimpedance reading. The more accurate this figure, the more accurate the result. Even a rough estimate (e.g. 18% for a lean man) is far better than omitting it. 3. Choose your activity level: Select the multiplier that best matches your typical week — from sedentary (1.2) to extra active (1.9). Activity level has a bigger impact on TDEE than body composition alone. 4. Read your BMR and TDEE: The Katch–McArdle BMR and TDEE are shown with full working. Compare the Cunningham and Mifflin–St Jeor figures to see how much the formulas diverge at your body composition. 5. Switch to solve-for-body-fat mode: Enter a target TDEE and the calculator works backwards: it tells you exactly what lean body mass — and therefore what body fat percentage — you need to achieve that metabolic rate at your current body weight. FAQ: Q: What is the Katch–McArdle formula and why is it different? A: Katch–McArdle (1996) calculates BMR using only lean body mass (LBM): BMR = 370 + 21.6 × LBM(kg). Because body fat is metabolically near-inert, removing it from the equation makes the formula independent of sex and height — the two variables that most confound other equations. A 70 kg man at 10% body fat has 63 kg of LBM; a 70 kg woman at 30% body fat has 49 kg. Their Mifflin BMRs differ modestly, but their Katch–McArdle BMRs differ by ~302 kcal — a gap that standard equations hide inside crude sex coefficients. Q: What is the Cunningham formula? A: The Cunningham (1980) equation is an earlier lean-mass formula: BMR = 500 + 22 × LBM(kg). It was derived primarily from athletic populations and tends to run 50–150 kcal/day higher than Katch–McArdle. Strength athletes and bodybuilders often find Cunningham closer to their measured RMR because muscle at high training volumes has a somewhat elevated metabolic cost per kilogram. Both formulas are shown side by side so you can bracket the likely range. Q: How accurate is Katch–McArdle versus Mifflin–St Jeor? A: In most validation studies, Katch–McArdle outperforms Mifflin–St Jeor for people with a known body fat percentage, with mean errors typically under 5% versus 7–10% for Mifflin. The catch is that you need an accurate body fat reading — a 5 percentage point error in BF% translates directly into a ~54 kcal/day BMR error for a 50 kg LBM. If you only have height and weight, Mifflin–St Jeor is still the better choice than guessing your body fat. Q: How do I measure my body fat percentage accurately? A: In descending order of accuracy: DEXA scan (±1–2%, gold standard), BodPod air displacement plethysmography (±2–3%), hydrostatic weighing (±2–3%), multi-site skinfold callipers by a trained technician (±3–4%), bioelectrical impedance (±3–5% under ideal hydration conditions). Consumer smart scales using BIA are convenient but can be off by 5–8% depending on hydration. Even an estimated figure from a visual body fat chart moves Katch–McArdle much closer to reality than omitting it entirely. Q: What does the "solve for body fat" mode do? A: It inverts the Katch–McArdle equation. Given your target TDEE and activity level, the calculator derives the BMR you need, then works back through BMR = 370 + 21.6 × LBM to find the required lean body mass, and finally divides by your total body weight to give the required body fat percentage. This tells you, concretely, how lean you need to be to reach a specific metabolic rate — useful when setting fat loss targets or planning a body recomposition. Q: Why does body fat percentage matter so much for TDEE? A: Fat tissue burns roughly 4–5 kcal per kg per day, while lean tissue (muscle, organs, bone) burns around 20–30 kcal per kg per day. Two people with the same body weight but different body compositions can easily differ by 200–400 kcal/day in resting metabolic rate. This is why a lean 80 kg athlete eats far more than a sedentary 80 kg person at the same apparent weight — their TDEE is genuinely higher, not just because of exercise output but because their resting engine runs hotter. #### Ovulation Calculator URL: https://geratools.com/ovulation-calculator Free ovulation calculator. Enter the first day of your last period and your cycle length to instantly see your fertile window, ovulation date, next period, and estimated due date — all calculated in your browser, no data uploaded. How to use: 1. Enter the first day of your last period: Pick the date your most recent period started (the first day of bleeding) using the date picker. 2. Set your cycle length: Enter how many days typically pass between the start of one period and the start of the next. The average is 28 days; normal range is 21–35 days. 3. Adjust the luteal phase if known: The luteal phase is the number of days from ovulation to the start of the next period. It is typically 12–16 days; 14 is the default. If you track basal body temperature or use OPKs, enter your measured value. 4. Choose how many cycles to forecast: Select 1–6 cycles. The calculator projects forward from your last period, showing a separate card per cycle. 5. Read your results: Each cycle card shows the fertile window (the 6-day span with the highest conception probability), the estimated ovulation day, the expected next period date, and an estimated due date if conception occurs. FAQ: Q: How does the calculator work out my ovulation date? A: It uses the standard two-phase cycle model. Ovulation falls approximately (cycle length minus luteal phase) days after the first day of your last period (LMP). With a 28-day cycle and a 14-day luteal phase, ovulation is on day 14. The formula is: ovulation day = LMP + (cycle_length - luteal_phase). Q: What is the fertile window? A: The fertile window is the span of days when intercourse can lead to conception. It covers the five days before ovulation plus ovulation day itself — six days in total. Sperm can survive in the fallopian tubes for 3–5 days, and the egg is viable for roughly 12–24 hours after release. The two or three days leading up to ovulation typically carry the highest pregnancy probability. Q: My cycle is not 28 days. Is this calculator still accurate? A: Yes — enter your actual average cycle length. The model adjusts the ovulation day and fertile window accordingly. A 35-day cycle shifts ovulation to around day 21; a 24-day cycle shifts it to around day 10. The calculator works for any cycle from 21 to 45 days. Q: What is the luteal phase and should I change it? A: The luteal phase is the second half of your cycle, from ovulation through the day before your next period. It is remarkably stable at 12–16 days for most people (the follicular phase varies; the luteal phase usually does not). If you have confirmed your luteal phase length via basal body temperature charting, enter it for more precise results. Otherwise the default of 14 days is a solid estimate. Q: How is the estimated due date calculated? A: The calculator adds 266 days to the estimated ovulation date. This reflects the average 266-day gestation period from conception. It is equivalent to the classic Naegele rule (LMP + 280 days) for a standard 28-day cycle with a 14-day luteal phase — but adjusted for your actual cycle length: due date = ovulation + 266 days. Q: Is this calculator a substitute for ovulation tests or medical advice? A: No. This tool provides statistical estimates based on average cycle physiology. Individual cycles vary due to stress, illness, weight changes, and other factors. Ovulation predictor kits (OPKs) detect the LH surge 12–36 hours before ovulation; basal body temperature (BBT) charting confirms ovulation retrospectively. If you are trying to conceive or suspect a cycle irregularity, consult a healthcare professional. #### Pregnancy Week Calculator URL: https://geratools.com/pregnancy-week-calculator Free pregnancy week calculator: enter your last period (LMP) or due date (EDD) to get your current gestational week, trimester, days remaining, and key developmental milestones. 100% private — runs in your browser. How to use: 1. Choose your input method: Select whether you know your last menstrual period (LMP) or your estimated due date (EDD). 2. Enter the date: Type or pick the first day of your last period, or your due date if you already have one from a scan. 3. Read your gestational week: The calculator shows your current week and extra days, which trimester you are in, and how many days remain until your due date. 4. Check the milestone panel: Scroll down to see the next developmental milestone and a list of milestones you have already passed. FAQ: Q: How is gestational age calculated from LMP? A: Gestational age (GA) = today minus the first day of your last menstrual period, counted in days, then expressed as complete weeks plus remainder days. Using Naegele's rule, the estimated due date (EDD) = LMP + 280 days (40 weeks). So if your LMP was 70 days ago, you are 10 weeks + 0 days pregnant. Q: What is Naegele's rule? A: Naegele's rule is the standard obstetric formula for estimating a due date: add 280 days (40 weeks) to the first day of the last menstrual period. It assumes a regular 28-day cycle and ovulation on day 14. The rule has been used clinically since the 19th century and remains the default when no ultrasound dating is available. Q: What is the difference between gestational age and fetal age? A: Gestational age is counted from the LMP and is the standard clinical measure — it is roughly 2 weeks longer than fetal age (which is counted from conception). When a doctor says you are 12 weeks pregnant, they mean 12 weeks of gestational age, not 12 weeks since the embryo formed. Q: When does each trimester start and end? A: The first trimester covers weeks 1–13 (days 0–97 from LMP), the second trimester covers weeks 14–27 (days 98–195), and the third trimester runs from week 28 to delivery (days 196–280+). These boundaries follow standard clinical convention; some sources place the second-trimester start at week 13+1 rather than week 14. Q: My EDD from a scan is different from this calculator — which is right? A: The ultrasound estimate is more accurate, particularly if it was performed in the first trimester (before 14 weeks). Naegele's rule assumes a perfect 28-day cycle with ovulation on day 14 — any variation shifts the true conception date. Always defer to the date your clinician assigns after a dating scan. Q: Is this calculator private? A: Yes. All dates and calculations happen entirely inside your browser using JavaScript. Nothing is sent to a server, stored, or logged. You can use it offline once the page has loaded. #### Fat-Burning Zone Calculator URL: https://geratools.com/fat-burning-zone-calculator Free fat-burning zone calculator. Enter your age, weight and resting heart rate to get your 5 personalised training zones, fat-burn zone in bpm, estimated fat oxidation rate in g/min, and calorie breakdown. Uses Tanaka HRmax and the Karvonen formula. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your age and weight: Age drives the HRmax estimate; weight scales the fat-oxidation rate estimate shown for each zone. 2. Add your resting heart rate: Measure it first thing in the morning before getting up. It makes the Karvonen calculation more personalised and accurate. 3. Choose your HRmax formula and zone method: Tanaka (208 minus 0.7 times age) is the most validated for adults. Switch to the Karvonen method to factor in your resting heart rate for tighter zone targets. 4. Read your fat-burn zone and train to it: The highlighted Zone 2 row shows your target bpm range and estimated fat oxidation in g/min. Aim to keep your heart rate inside that window during steady-state cardio sessions. FAQ: Q: What is the fat-burning zone? A: The fat-burning zone is typically Zone 2 of the five-zone heart-rate model, sitting at 60–70% of your maximum heart rate. At this intensity your aerobic system can supply enough oxygen to use fat (via beta-oxidation) as the dominant fuel. Although the percentage of calories from fat is actually higher at very low intensities, the absolute amount of fat burned per minute peaks in this 60–70% range — which is why it earns the "fat-burn zone" label. Q: How is maximum heart rate (HRmax) estimated? A: The calculator offers three validated formulas. Standard (220 minus age) is the most widely known but has high individual variability (plus or minus 10–12 bpm). Tanaka (208 minus 0.7 times age) is derived from a 2001 meta-analysis of 351 studies and is more accurate for adults. Gelish (207 minus 0.7 times age) is similar. For the most accurate result, measure your own HRmax by entering it as a custom value in the optional override field. Q: What is the Karvonen formula? A: The Karvonen method (also called the Heart Rate Reserve method) accounts for your resting heart rate when setting zones. Target HR = (HRmax minus HRrest) times intensity% plus HRrest. Because it uses your heart rate reserve (HRmax minus HRrest), it produces personalised zones that are tighter and more meaningful than simple percentage-of-HRmax zones. A well-trained athlete with a resting HR of 45 bpm gets very different Zone 2 targets to a sedentary person with a resting HR of 80 bpm, even if both have the same HRmax. Q: How accurate is the fat oxidation estimate? A: The g/min figure is a population-level approximation based on Achten and Jeukendrup (2003) and scaled by body weight. Individual fat oxidation varies considerably with aerobic fitness, diet (especially carbohydrate intake), time since last meal, and genetics. Highly trained endurance athletes can oxidise 0.8–1.0 g/min at peak; untrained individuals are closer to 0.3–0.5 g/min. Use the figure as a directional guide, not a precise measurement. Q: Should I always train in the fat-burning zone to lose weight? A: Not necessarily. While Zone 2 burns the highest proportion of fat, higher-intensity training burns more total calories per minute and can elevate metabolism for hours afterward (EPOC effect). A well-rounded programme combines Zone 2 base work for fat oxidation and aerobic efficiency with some Zone 4–5 intervals for calorie burn and fitness. Zone 2 is particularly valuable for those building an aerobic base or recovering between hard sessions. Q: How do I measure my resting heart rate accurately? A: Lie still for 5 minutes after waking — before checking your phone or getting out of bed. Count your pulse for 60 seconds (or 30 seconds and double it), or use a heart-rate monitor. Average three consecutive mornings for the most reliable number. Resting HR for adults typically ranges from 60–100 bpm; endurance athletes often sit at 40–60 bpm. #### Calories in Recipe Calculator URL: https://geratools.com/calories-in-recipe-calculator Free recipe calorie calculator. Add every ingredient by weight, get total kcal plus protein, carbs and fat — for the whole recipe and per serving. 100% client-side, nothing is uploaded. How to use: 1. Name your recipe and set servings: Enter a recipe name and the number of portions so the tool can divide the totals correctly. 2. Add each ingredient row: For every ingredient, enter the name, the quantity in grams, and the calories (plus protein, carbs and fat if you want macro data) per 100 g. Use the ingredient library search to auto-fill common foods. 3. Read total and per-serving figures: The results update instantly. The top cards show whole-recipe and per-serving kcal and macros; the coloured bar shows the protein/carbs/fat split; the table itemises every ingredient. 4. Copy the summary: Click Copy summary to paste a plain-text breakdown into a notes app, spreadsheet or meal-plan document. FAQ: Q: How is the calorie count calculated? A: Each ingredient contributes kcal = (kcal per 100 g / 100) x weight in grams. The tool sums every ingredient and divides by the number of servings. It is the same arithmetic used on every nutrition label and by dietitians. Q: Where do I find the kcal per 100 g for an ingredient? A: Check the nutrition label on the packet — it always shows energy per 100 g. For loose fresh produce, search the ingredient library built into the tool; it contains 25 common foods with standard values. You can also check any online nutrition database such as the USDA FoodData Central or the UK Nutrient Databank. Q: Does cooking method change the calorie count? A: Yes. Boiling does not add calories but can increase water weight, diluting the kcal-per-100-g figure. Frying adds the calories of the oil absorbed. The most accurate approach is to enter each ingredient at the weight you actually add (raw, cooked, or drained) and use a matching per-100-g value — for example use a cooked-rice figure if you weigh rice after cooking. Q: Should I weigh ingredients raw or cooked? A: Either works, provided the kcal-per-100-g value matches the state you are weighing. Raw weights paired with raw-food nutritional values give identical results to cooked weights paired with cooked values. Mixing the two (e.g. raw weight with a cooked-food figure) is the most common source of error in home calorie counting. Q: How accurate is this calculator? A: The arithmetic is exact for the numbers you enter. Real-world accuracy depends on your food database figures (which are averages with natural variation) and the precision of your scales. A kitchen scale reading to 1 g combined with label values is accurate to within roughly 5–10%, which is sufficient for practical meal planning. Professional nutritionists use the same method. Q: Can I use this for liquids like olive oil or milk? A: Yes. Use grams rather than millilitres for best accuracy. Water-based liquids (skimmed milk, broths) are close to 1 g/ml, so 100 ml ≈ 100 g. Oils are lighter — 1 tablespoon of olive oil is about 13.5 g. The ingredient library includes olive oil and whole milk with standard per-100-g values. ### Chemistry #### Aquarium CO2 / pH / KH Calculator URL: https://geratools.com/co2-ph-kh-calculator Uses the carbonate equilibrium relationship to compute dissolved CO2 in ppm from your aquarium pH and KH readings, with a planted-tank target band. For planted tank hobbyists tuning CO2 injection. How to use: 1. Measure pH and KH: Test your tank water for pH and carbonate hardness (KH) in degrees, using a reliable liquid test kit. 2. Enter both values: Type the pH reading and the KH in dKH into the fields. 3. Read the dissolved CO2: The tool returns dissolved CO2 in ppm and flags whether it is below, within, or above the typical 20 to 30 ppm planted-tank range. FAQ: Q: What is the CO2 from pH and KH formula? A: Dissolved CO2 in ppm is approximately 3 times KH (in dKH) times 10 to the power of (7 minus pH). This comes from the carbonate buffer equilibrium, where adding CO2 forms carbonic acid that lowers pH for a given carbonate hardness. The constant 3 folds in the unit conversions for aquarium use. Q: What CO2 level should a planted tank target? A: Most high-light planted tanks run 20 to 30 ppm dissolved CO2. Below about 15 ppm plant growth is carbon-limited; above 30 ppm fish and shrimp can suffocate. The 30 ppm point corresponds to roughly a 1.0 drop in pH from the fully degassed value at a given KH. Q: Why can this reading be misleading? A: The formula assumes CO2 is the only acid affecting pH. Tanks dosed with phosphate buffers, peat, tannins, or other acids will read a falsely high CO2 because something other than carbonic acid is lowering pH. Treat the number as an estimate and watch livestock behaviour. Q: How do I raise or lower dissolved CO2? A: Increase the CO2 injection rate (bubbles per second) or improve circulation to dissolve more gas, which lowers pH and raises the calculated CO2. To reduce CO2, cut injection or add surface agitation to off-gas it. Adjust slowly and re-test, since fish respond to sudden CO2 swings. Q: Does temperature affect this calculation? A: Temperature shifts the carbonate equilibrium constants slightly, but for the 22 to 28C range typical of planted tanks the standard 3 times KH times 10^(7 minus pH) formula is accurate enough for setting injection rates. Use a drop checker as a cross-check. #### Dilution Calculator (C₁V₁ = C₂V₂) URL: https://geratools.com/dilution-c1v1-c2v2 Apply C₁V₁ = C₂V₂ to solve for any missing variable when diluting a stock solution to a target concentration and volume, with the diluent amount and dilution factor. A browser-based lab calculator for scientists, pharmacists, and QC analysts. How to use: 1. Enter the values you know: Fill in any three of the four boxes — stock concentration C₁, stock volume V₁, final concentration C₂, and final volume V₂. 2. Leave the unknown blank: Leave exactly one box empty; that is the variable the tool will solve for using the dilution equation. 3. Read the result and diluent: The tool shows the solved value, the dilution factor, and how much diluent to add to reach the final volume. FAQ: Q: What is the C₁V₁ = C₂V₂ equation? A: It states that the amount of solute is conserved during dilution. The concentration of the stock times its volume equals the concentration of the final solution times its volume, so you can solve for any one unknown if you know the other three. Q: Which units should I use? A: Any units, as long as the two concentrations share a unit and the two volumes share a unit. If C₁ and C₂ are both in molar and V₂ is in millilitres, the V₁ result comes out in millilitres. The tool does not assume units. Q: How much diluent do I add? A: You add diluent equal to the final volume minus the stock volume, V₂ minus V₁. Measure out the stock volume first, then top up to the final volume — do not simply add V₂ of diluent, which would over-dilute. Q: What is the dilution factor? A: The dilution factor is C₁ divided by C₂, the ratio of stock to final concentration. A factor of 5 means a 1-in-5 dilution: one part stock to four parts diluent, giving a fifth of the original concentration. Q: Can I use this for serial dilutions? A: Yes, one step at a time. Compute each step's stock volume against the next target concentration, then use that diluted solution as the stock for the following step. The same equation applies at every stage of a serial dilution. #### Dilution Factor & Back-Calculation Tool URL: https://geratools.com/dilution-factor-calculator Calculate the dilution factor from sample and diluent volumes, then back-calculate the original sample concentration from the measured diluted value. A core tool for analytical, microbiology, and clinical labs. Runs in your browser. How to use: 1. Enter the sample volume: Type the volume of original sample (the aliquot) you took, in any consistent unit such as mL or uL. 2. Enter the diluent volume: Type the volume of solvent or buffer you added to the sample, in the same unit. 3. Read the factor and original: The tool shows the dilution factor and, if you enter the measured diluted concentration, multiplies it back up to the original. FAQ: Q: How is the dilution factor defined? A: The dilution factor is the total volume divided by the sample volume, where total volume is sample plus diluent. Mixing 1 part sample with 9 parts diluent gives a total of 10 parts, so the factor is 10, written as a 1:10 or ten-fold dilution. Q: Is it sample-to-diluent or sample-to-total? A: The factor is sample to total. A 1:10 dilution means 1 part sample in 10 parts total, which is 1 part sample plus 9 parts diluent. Confusing the two is the most common dilution error, so this tool always uses sample over total. Q: How do I get the original concentration back? A: Multiply the concentration you measured in the diluted sample by the dilution factor. If a diluted sample reads 5 units per mL at a ten-fold dilution, the original was 50 units per mL. Enter the measured value and the tool does this for you. Q: Does this work for serial dilutions? A: Each step uses this same factor. For a serial dilution, multiply the individual step factors together. Three successive ten-fold steps give an overall factor of 1,000, so multiply your final reading by 1,000 to recover the starting concentration. Q: Do the volume units matter? A: Only that both volumes use the same unit, because the factor is a ratio and the units cancel. Mix microlitres with microlitres or millilitres with millilitres. The concentration unit you enter is simply carried through to the original result. #### D&D Polymorph Stat Block Reference URL: https://geratools.com/dnd-polymorph-stat-block-converter Set a challenge-rating cap to display a filtered list of polymorph-legal beasts with HP, AC, speeds, and key features. For D&D 5e Druid and Wizard players choosing a Polymorph or Wild Shape target. How to use: 1. Set your CR cap: Polymorph turns a creature into a beast whose challenge rating is no higher than the target's level (or CR). Set the cap to that value. 2. Filter by movement if needed: Optionally require a fly or swim speed when you need a specific escape or mobility option. 3. Compare the stat blocks: The list shows every legal beast at or below your cap with HP, AC, speeds, and a key feature so you can pick the best one. FAQ: Q: What CR can I polymorph into? A: The Polymorph spell transforms a target into a beast whose challenge rating is equal to or less than the target's level (or its own CR if it has no class levels). A 5th-level character can become any beast up to CR 5. Q: Why does Polymorph only allow beasts? A: The spell specifically restricts the new form to a beast, the creature type that includes most animals and dinosaurs. Monstrosities, dragons, and elementals are off the table, which is why the Giant Ape (CR 7) is a frequent high-end pick. Q: How do hit points work after polymorphing? A: You gain the new form's hit points and Hit Dice. When those run out you revert with any leftover damage carrying to your original form, so a big-HP beast like the Giant Ape acts as a large temporary buffer. Q: What is the best low-level polymorph target? A: At CR 1 the Giant Spider and Brown Bear are popular for their reach, grapple, and respectable HP. The Giant Toad can swallow smaller foes. The right pick depends on whether you want damage, control, or mobility. Q: Does Polymorph keep my mental stats? A: Yes. The creature keeps its Intelligence, Wisdom, and Charisma, alignment, and personality, but takes the beast's physical stats, and cannot cast spells or use features requiring hands or speech while transformed. #### Garden Soil pH Amendment Calculator URL: https://geratools.com/garden-ph-soil-amendment-calculator Enter your current soil pH, target pH, soil texture (sandy, loam, or clay), and area in square feet to compute pounds of agricultural lime to raise pH or elemental sulfur to lower it. For home gardeners and growers. How to use: 1. Test and enter your pH: Use a soil test to enter your current pH and the target pH for your crop, such as 6.5 for most vegetables or 4.5 to 5.5 for blueberries. 2. Choose soil texture and area: Select sandy, loam, or clay (buffering increases in that order) and enter the bed area in square feet. 3. Read the amendment amount: The tool tells you whether to add lime or sulfur and how many pounds, based on standard application rates per pH point per 100 square feet for your soil type. FAQ: Q: How much lime raises soil pH by one point? A: Roughly 5 pounds of agricultural lime per 100 square feet raises pH by about one point in loam. Sandy soil needs less (about 3.5 lb) and clay needs more (about 7 lb) because clay buffers pH more strongly. This tool scales to your area and pH gap. Q: How do I lower soil pH? A: Add elemental sulfur. Soil bacteria slowly convert it to sulfuric acid, lowering pH. Roughly 1 to 2 pounds of elemental sulfur per 100 square feet lowers pH by about one point depending on soil texture. The tool gives the sulfur amount when your target is below your current pH. Q: Why does soil type change the amount? A: Clay and high-organic soils resist pH change because they have many sites that hold acidity, called buffering capacity. Sandy soils have little buffering and change quickly. The tool applies lower rates to sand and higher rates to clay to reflect this. Q: How long until the pH changes? A: Lime takes several weeks to months to fully react, and elemental sulfur depends on warm, moist, biologically active soil and can take a full season. Apply and incorporate amendments well before planting, then re-test rather than adding more too soon. Q: Can I add too much? A: Yes. Over-liming can push pH too high and lock out iron and manganese, while excess sulfur can over-acidify. Change pH in steps of no more than about one point per application, incorporate thoroughly, water in, and re-test before a second round. #### Air Enthalpy Calculator (HVAC) URL: https://geratools.com/hvac-economizer-enthalpy-calculator Computes moist-air enthalpy from dry-bulb temperature and humidity, deriving the humidity ratio from wet-bulb temperature or relative humidity, matching psychrometric-chart values at sea level. For HVAC engineers and controls technicians setting up enthalpy economizer control. How to use: 1. Enter the dry-bulb temperature: Type the dry-bulb air temperature in degrees Fahrenheit for the air stream you want to evaluate, such as outdoor air. 2. Choose a humidity input: Switch between wet-bulb temperature and relative humidity, then enter the value. The tool derives the humidity ratio either way. 3. Read the enthalpy: The tool returns the humidity ratio and the total enthalpy in BTU per pound of dry air, the value an enthalpy economizer compares to decide on free cooling. FAQ: Q: What is the enthalpy formula used here? A: Total moist-air enthalpy is h = 0.24 × T + W × (1061 + 0.444 × T), where T is dry-bulb in Fahrenheit and W is the humidity ratio in pounds of water per pound of dry air. The first term is sensible heat of the dry air, the second is the latent and sensible heat carried by the water vapor. Q: How is humidity ratio found from relative humidity? A: The tool computes saturation vapor pressure at the dry-bulb temperature, multiplies by the relative humidity to get actual vapor pressure, then applies W = 0.621945 × p / (Patm − p) at standard sea-level pressure of 14.696 psia. Q: How is humidity ratio found from wet-bulb? A: It uses the standard psychrometric relation tying the humidity ratio to the saturation humidity ratio at the wet-bulb temperature and the dry-bulb minus wet-bulb depression, the same equation behind a psychrometric chart at sea level. Q: Why do economizers use enthalpy instead of temperature? A: A temperature economizer ignores moisture, so it can pull in cool but very humid outdoor air that actually adds latent load. An enthalpy economizer compares total heat content, enabling free cooling only when outdoor air is both cool and dry enough to reduce the coil load. Q: Is this accurate at altitude? A: The humidity-ratio step assumes sea-level pressure of 14.696 psia. At higher elevations the atmospheric pressure is lower, which raises the humidity ratio for the same conditions. Adjust the barometric pressure input for accurate enthalpy above a few thousand feet. #### Antibody Dilution Calculator for IHC / ICC URL: https://geratools.com/immunohistochemistry-dilution Takes a target working dilution, number of sections, volume per section, and a dead-volume overage to compute the exact microlitres of stock antibody and diluent for IHC and ICC staining. Optionally derives the dilution from stock and target concentrations. Runs in your browser. How to use: 1. Enter the dilution: Type the working dilution as the N in 1:N, for example 200 for a 1:200 dilution, or leave it and use the optional concentration fields. 2. Describe the run: Enter the number of sections, the volume each section needs in microlitres, and a dead volume to cover pipetting loss. 3. Pipette the volumes: The tool reports the microlitres of stock antibody and diluent to combine for the total working volume. FAQ: Q: What does a 1:200 dilution actually mean? A: It means one part antibody made up to 200 total parts. So in a 1000 microlitre working solution you add 5 microlitres of stock antibody and 995 microlitres of diluent. The tool does this arithmetic and adds your dead volume on top. Q: Why add a dead volume? A: Pipetting loss, evaporation, and the need to fully cover each section mean you should prepare a little more than the bare minimum. The dead volume is a small overage so you never run short on the last slide. Q: Can I work from concentrations instead of a ratio? A: Yes. Enter the stock concentration in mg/mL and the target working concentration in micrograms per millilitre. The tool converts the stock to the same units and divides to find the dilution factor, then computes the volumes from there. Q: How do I choose the right dilution? A: Manufacturers suggest a starting range, but every new lot and tissue should be titrated. Run a small series such as 1:100, 1:200, and 1:400 and pick the dilution that gives strong specific signal with the least background. This tool gives you the exact volumes for each test point. Q: Does this apply to both IHC and ICC? A: Yes. The dilution mathematics is identical for tissue sections in immunohistochemistry and cultured cells in immunocytochemistry. Only the volume per sample and the diluent chemistry differ, both of which you set as inputs. #### Knots / MPH / km/h / m/s Speed Converter URL: https://geratools.com/knots-mph-kmh-converter Convert between knots, miles per hour, kilometres per hour, feet per second, and metres per second in real time using exact SI-anchored factors. Mariners, pilots, meteorologists, and sports coaches use this as a constant reference. How to use: 1. Enter a speed: Type the speed value you want to convert into the input box. 2. Pick the input unit: Choose whether your value is in knots, mph, km/h, ft/s, or m/s from the dropdown. 3. Read every conversion: All five units update instantly, with the input unit greyed out so the converted figures stand out. FAQ: Q: How many mph is one knot? A: One knot is exactly 1.150779 miles per hour. The simple rule of thumb is that a knot is about 15 percent faster than a mile per hour, so 20 knots is roughly 23 mph. Q: Why is a nautical mile different from a statute mile? A: A nautical mile is 1852 metres, defined to approximate one minute of latitude, which makes chart work convenient. A statute land mile is 1609.344 metres. Because a knot is one nautical mile per hour, it is faster than a mile per hour. Q: How do I convert knots to km/h quickly? A: Multiply knots by 1.852 to get km/h, since one nautical mile is exactly 1.852 kilometres. So 30 knots is about 55.6 km/h. To go back, divide km/h by 1.852. Q: What is the exact factor for knots to m/s? A: One knot equals 1852 divided by 3600 metres per second, which is 0.514444 m/s. This tool converts every input to metres per second first and then out to each unit, so all results are mutually consistent. Q: Is this useful for wind speed? A: Yes. Meteorologists often report wind in m/s or km/h while mariners and aviators use knots. Converting here lets you cross-check a forecast and look the value up on the Beaufort scale if needed. #### Osmolarity of Solution Calculator URL: https://geratools.com/osmolarity-of-solution Sum the osmolal contributions of every solute, each weighted by its van't Hoff dissociation factor, to compute total osmolarity in mOsm/L and compare it against plasma tonicity. For pharmacy, biochemistry, and cell biology. How to use: 1. Choose a unit: Select whether you will enter concentrations in mmol per litre or mol per litre. 2. Add each solute: Enter every solute with its concentration and van't Hoff factor, the number of particles each formula unit produces on dissolving. 3. Read the total: The tool multiplies each concentration by its dissociation factor, sums them, and reports total osmolarity in mOsm/L with a tonicity note. FAQ: Q: What is osmolarity? A: Osmolarity is the total concentration of osmotically active particles per litre of solution, measured in osmoles or milliosmoles per litre. It governs the osmotic pressure a solution exerts and therefore how it moves water across cell membranes. Q: How is the van't Hoff factor used? A: Each solute contributes its molar concentration multiplied by its van't Hoff factor, which is the number of particles it splits into. Glucose stays as one particle, so its factor is 1, while NaCl splits into a sodium and a chloride ion, giving a factor of 2. Q: What is the difference between osmolarity and osmolality? A: Osmolarity is per litre of total solution while osmolality is per kilogram of solvent water. They are nearly identical in dilute aqueous solutions but diverge as concentration rises, because solutes take up volume that the per-litre figure includes and the per-kilogram figure does not. Q: What osmolarity is isotonic with human plasma? A: Human plasma sits at roughly 285 to 295 mOsm per litre. Solutions in that band are isotonic, lower values are hypotonic and tend to swell cells, and higher values are hypertonic and tend to shrink them. The tool flags the result against this range. Q: Why might my measured osmolarity be lower than calculated? A: The calculator assumes each electrolyte dissociates completely. In real solutions ion pairing at higher concentrations reduces the effective number of free particles, an effect captured by the osmotic coefficient, so measured osmolarity is usually slightly below the ideal calculated value. #### Urine Specific Gravity to Osmolality Converter URL: https://geratools.com/urine-specific-gravity-osmolality Convert between urine specific gravity and approximate osmolality using the empirical relation Uosm ≈ (SG − 1.000) × 40,000, with a hydration interpretation. Used in nephrology, nutrition, and sports medicine. How to use: 1. Choose the direction: Select whether you are converting specific gravity to osmolality or osmolality to specific gravity. 2. Enter the measured value: Type the urine specific gravity (for example 1.020) or the urine osmolality in mOsm per kg. 3. Read the result: The tool returns the converted value plus a hydration interpretation, from dilute to very concentrated. FAQ: Q: What formula converts specific gravity to osmolality? A: The widely used empirical relation is osmolality (mOsm/kg) ≈ (specific gravity − 1.000) × 40,000. So a specific gravity of 1.020 corresponds to roughly 800 mOsm/kg. The inverse is specific gravity ≈ 1.000 + osmolality / 40,000. Q: How accurate is this conversion? A: It is a reasonable estimate for ordinary urine containing small solutes such as urea and electrolytes. It is not a substitute for laboratory osmometry, and the two measures can diverge by a wide margin when unusual solutes are present. Q: When does the relationship break down? A: Large or heavy molecules — glucose in diabetes, radiographic contrast media, mannitol, or significant proteinuria — raise specific gravity disproportionately to osmolality. In these settings the estimate overstates true osmolality and measured osmolality should be used. Q: What values indicate dehydration? A: As a guide, a specific gravity above 1.020 or osmolality above about 800 mOsm/kg suggests concentrated urine consistent with dehydration, while a specific gravity below 1.010 or osmolality below about 350 indicates dilute, well-hydrated urine. Q: Why is osmolality sometimes preferred over specific gravity? A: Osmolality counts the number of dissolved particles regardless of their size, which is what determines the kidney's concentrating ability. Specific gravity reflects both number and mass of particles, so it can be skewed by a few heavy molecules. #### Dilution Calculator (C1V1 = C2V2) URL: https://geratools.com/dilution-calculator Free C1V1 = C2V2 dilution calculator. Solve for stock concentration, stock volume, final concentration or final volume, mix molar (M, mM, µM) and mass units (mg/mL, g/L, %), see the working, dilution factor and solvent to add. 100% in your browser. How to use: 1. Choose the unknown: Select whether to solve for C1, V1, C2 or V2 in the dilution equation. 2. Enter the three known values with units: Type the two concentrations and one volume you know, picking units such as M, mM, mg/mL, g/L, L or mL for each. 3. Read the result and working: The unknown appears instantly in your chosen unit, alongside the dilution factor, the solvent to add and an expandable step-by-step working. FAQ: Q: What is the dilution equation? A: The dilution equation is C1 × V1 = C2 × V2, where C1 and V1 are the stock (concentrated) solution's concentration and volume, and C2 and V2 are the final (diluted) solution's concentration and volume. It holds because diluting adds only solvent, so the amount of solute is conserved. Q: How do I work out the stock volume I need? A: Rearrange to V1 = (C2 × V2) ÷ C1. For example, to make 100 mL of 2 M solution from a 10 M stock, V1 = (2 × 100) ÷ 10 = 20 mL of stock, then top up to 100 mL with solvent. Q: Can I mix different units like mM and µM, or mg/mL and g/L? A: Yes, within the same family. The calculator converts every value to a common base (mol/L for molar units, g/L for mass units) before solving, so you can enter C1 in M and C2 in mM. It will not mix molar and mass units together, because converting between them needs a molar mass. Q: How much solvent do I add? A: Solvent to add equals the final volume minus the stock volume, V2 − V1. The tool shows this automatically whenever both volumes are known or solved, in your chosen final-volume unit. Q: What is a dilution factor? A: The dilution factor is the ratio of final volume to stock volume, V2 ÷ V1, which equals C1 ÷ C2 for a valid dilution. A factor of 10 (a 1:10 dilution) means one part stock plus nine parts solvent, reducing the concentration tenfold. Q: Does the % unit mean weight/volume? A: Yes. The % option is percent weight/volume (w/v), defined as grams of solute per 100 mL of solution, so 1 percent w/v equals 10 g/L. It sits in the mass family alongside g/L, mg/mL, mg/L (ppm) and µg/mL. Q: Can I use this for serial dilutions? A: Yes. Apply the equation one step at a time: each diluted solution becomes the stock for the next step. Chaining several modest dilution factors (for example three 1:10 steps for a 1:1000 result) is more accurate than one huge step because pipetting tiny volumes carries more error. #### Molar Mass Calculator URL: https://geratools.com/molar-mass-calculator Free molar mass calculator. Type any chemical formula like Ca(OH)2, (NH4)2SO4 or CuSO4.5H2O and get the molar mass in g/mol, the percent composition by mass, and a grams to moles converter. IUPAC standard atomic weights, 100% in your browser. How to use: 1. Type a chemical formula: Enter a formula using standard symbols and subscripts, such as H2O, NaCl, or Ca(OH)2. Capitalisation matters: Co is cobalt, CO is carbon monoxide. 2. Use brackets and hydrate dots for groups: Parentheses or square brackets with a multiplier work, like (NH4)2SO4, and you can write a hydrate as CuSO4.5H2O. 3. Read the molar mass and composition: The total molar mass in g/mol appears with a table of each element atoms, atomic weight, mass contribution and percent by mass. 4. Convert grams and moles: Switch the converter to "I know the mass" or "I know the moles" to turn one into the other and see the molecule count from Avogadro number. FAQ: Q: How is molar mass calculated from a formula? A: The calculator counts how many atoms of each element the formula contains, multiplies each count by that element standard atomic weight, and adds the results. In symbols, molar mass = sum over elements of (count times atomic weight). For glucose C6H12O6 that is 6 times 12.011 plus 12 times 1.008 plus 6 times 15.999, which is about 180.16 g/mol. Q: Which atomic weights does it use? A: It uses the IUPAC 2021 conventional standard atomic weights, the same values printed on most periodic tables, so the answers match textbook and exam mark schemes. Elements with no stable isotope use the mass number of a commonly cited isotope. Q: Can it handle brackets, square brackets and hydrates? A: Yes. Parentheses and square brackets with multipliers are supported, for example Ca(OH)2, Al2(SO4)3 and K4[Fe(CN)6]. Hydrates can be written with a dot and coefficient such as CuSO4.5H2O or Na2CO3.10H2O; the middle dot works too. Q: What is percent composition by mass? A: It is the share of the total molar mass contributed by each element, written as a percentage. For water the oxygen percent is 15.999 divided by 18.015, about 88.8 percent, and hydrogen makes up the remaining 11.2 percent. The tool shows these in the table and as a coloured bar. Q: How do I convert between grams and moles? A: Moles equal mass in grams divided by molar mass, and mass equals moles times molar mass. The built-in converter does both directions and also reports the number of molecules using Avogadro number, 6.02214076 times 10 to the 23 per mole. Q: Is molar mass the same as molecular weight or formula weight? A: Numerically they are the same figure. Molecular weight (or relative molecular mass) is dimensionless, measured relative to carbon-12, while molar mass carries units of g/mol; formula weight is the same idea for ionic compounds that have no discrete molecule. This tool reports the value in g/mol. Q: Is anything uploaded? A: No. The formula is parsed entirely in your browser with JavaScript and nothing ever leaves your device. #### Cocktail Dilution Calculator URL: https://geratools.com/cocktail-dilution-calculator Free cocktail dilution calculator. Enter your spirits, liqueurs and mixers, pick stirred/shaken/built, and see dilution water added, final ABV, serve temperature and ice remaining. Runs 100% in your browser. How to use: 1. Add your ingredients: List every liquid in the glass — spirit, vermouth, liqueur, juice, bitters. Enter the volume in ml and the ABV percentage for each. 2. Choose a mixing method: Pick Stirred for spirit-forward drinks like Negronis and Manhattans, Shaken for sours and Daiquiris, or Built on ice for Spritzes and Old Fashioneds served over a rock. 3. Set ice mass and time: Enter the ice mass in grams (a standard cocktail glass prep uses 150–250 g) and how many seconds you stir or shake. 4. Read the results: The calculator shows dilution water added, final dilution percentage, final ABV, estimated serve temperature and how much ice remains unmelted. FAQ: Q: Why does dilution matter in cocktails? A: Every professional cocktail recipe is designed with a specific amount of dilution in mind. Too little and the drink is harsh, over-proof and unbalanced. Too much and it tastes flat and watery. Understanding dilution lets you hit the same result every time regardless of ice temperature, glass size or technique. Q: How is cocktail dilution calculated? A: The calculator uses a two-step model. First, a thermodynamic energy balance: the heat removed from the liquid as it cools equals the mass times specific heat times the temperature drop (Q = m × Cp × ΔT). That heat melts ice via the latent heat of fusion (334 kJ/kg). Second, an empirical rate cap based on David Arnold's bartending research — roughly 0.35 ml of water per second when stirring and 0.65 ml/s when shaking. The lower of the two values is used, which reflects the physical reality that you cannot melt more ice than the energy budget allows. Q: What is the formula for final ABV after dilution? A: Final ABV (%) = (total alcohol volume / final total volume) × 100, where total alcohol volume is the sum of (ingredient volume × ABV fraction) across all ingredients, and final total volume is the pre-dilution liquid volume plus the dilution water added. Q: How much does stirring dilute a cocktail? A: A classic 30-second stir with 200 g of freezer ice at -18 °C typically adds 10–20 ml of water to a 90 ml spirit-forward drink — around 15–20% dilution by final volume. Shaking for the same time adds roughly twice as much because the violent agitation increases ice surface contact and the aeration effect drops the temperature further. Q: Is a shaken cocktail more diluted than a stirred one? A: Yes. Shaking is roughly 1.5–2× more diluting than stirring for the same duration. This is intentional — shaken drinks (Daiquiri, Margarita, Whisky Sour) contain citrus or dairy that benefits from the extra dilution and aeration, while stirred drinks (Martini, Manhattan, Negroni) preserve texture and clarity by stirring gently. Q: What temperature should a cocktail be served at? A: A well-stirred spirit-forward cocktail should be near 0 °C when it hits the glass. A shaken drink chilled to -5 °C warms quickly once poured, so serving in a pre-chilled coupe or Nick & Nora glass is important. Built drinks over a single large rock sit around 4–10 °C and dilute slowly as you drink. #### Titration Calculator URL: https://geratools.com/titration-calculator Free online titration calculator: solve for analyte concentration, titrant volume, titrant concentration or analyte volume using the standard equivalence-point formula C_aV_a/n_a = C_tV_t/n_t. Supports any acid-base, redox or precipitation titration stoichiometry. Fully client-side. How to use: 1. Choose what to solve for: Pick the unknown from the "Solve for" dropdown — analyte concentration (C_a), volume of titrant (V_t), titrant concentration (C_t), or volume of analyte (V_a). 2. Enter the stoichiometric ratio: Set n_a and n_t from the balanced equation. For HCl + NaOH both equal 1; for H_2SO_4 + NaOH use n_a = 1 and n_t = 2. 3. Fill in the three known values: Enter the three values you already know. Concentrations go in mol/L (molarity); volumes go in mL. 4. Read the result: The answer appears instantly in the result box along with the full working line you can copy. FAQ: Q: What formula does this titration calculator use? A: It uses the standard equivalence-point relationship C_a × V_a / n_a = C_t × V_t / n_t, where C is concentration in mol/L, V is volume in mL, and n is the stoichiometric coefficient from the balanced equation. At the equivalence point the moles of analyte neutralised exactly equal the moles of titrant delivered (adjusted for stoichiometry), so this equation holds exactly. Q: What is the mole ratio (n_a and n_t)? A: These come from the balanced chemical equation. For a 1:1 reaction such as HCl + NaOH → NaCl + H_2O both are 1. For H_2SO_4 + 2 NaOH → Na_2SO_4 + 2 H_2O, n_a = 1 and n_t = 2 (two moles of NaOH react per mole of sulfuric acid). Entering the wrong ratio is the most common source of error in titration calculations. Q: How do I find the concentration of an unknown acid? A: Select "Analyte concentration (C_a)" as the unknown. Enter the volume of acid you placed in the flask (V_a), the concentration of your NaOH standard solution (C_t), and the volume of NaOH used to reach the endpoint (V_t). The calculator applies C_a = C_t × V_t × n_a / (V_a × n_t) and shows the molarity of the acid. Q: Can this calculator handle diprotic or triprotic acids? A: Yes. For a diprotic acid such as H_2SO_4 titrated with NaOH to both equivalence points, set n_a = 1 and n_t = 2 (for the second equivalence point). For a triprotic acid like H_3PO_4 reaching its third equivalence point, use n_a = 1, n_t = 3. The formula scales linearly with the mole ratio. Q: What units should I use? A: Enter all concentrations in mol/L (molar, M) and all volumes in millilitres (mL). The calculator converts volumes to litres internally for the mole calculation, so the displayed result is always back in mol/L or mL as appropriate. Q: Does this work for redox and precipitation titrations too? A: Yes. The equivalence-point formula is general — it applies to any titration where you have a known stoichiometric ratio between titrant and analyte. For a permanganate–oxalate redox titration (5 moles oxalate per 2 moles permanganate) set n_a = 5 and n_t = 2. For precipitation titrations, set the mole ratio from the balanced ionic equation in the same way. #### Stoichiometry Calculator URL: https://geratools.com/stoichiometry-calculator Free stoichiometry calculator. Work out molar mass and elemental composition, convert moles to grams to particles, find the limiting reagent and theoretical yield, calculate molarity or dilution, and solve the ideal gas law PV=nRT. 100% client-side — nothing is uploaded. How to use: 1. Choose a calculator mode: Select from molar mass, moles/grams/particles, limiting reagent, percent yield, concentration, or ideal gas law. 2. Enter a molecular formula: Type a formula such as H2SO4, Ca(OH)2, or Fe2(SO4)3 — the parser handles nested brackets and subscripts automatically. 3. Fill in the known values: Enter the quantities you know (mass, volume, temperature, pressure, moles) and the tool instantly returns the unknown with full working. 4. Copy the results: Use the Copy results button to transfer the output to your clipboard for lab reports or homework. FAQ: Q: What is stoichiometry? A: Stoichiometry is the branch of chemistry that uses the balanced chemical equation and molar masses to relate the quantities of reactants and products. The mole (6.022 x 10^23 particles) is the central unit, and every calculation converts real-world masses into moles, applies the integer ratios from the balanced equation, then converts back. Q: How does the molar mass calculator work? A: It parses the molecular formula character by character, extracting element symbols and subscripts (including nested brackets such as Ca(OH)2). Each element's atomic mass (from the IUPAC 2021 table) is multiplied by its subscript count. The sum is the molar mass in g/mol. The percentage composition of each element is then (element contribution / molar mass) x 100. Q: How is the limiting reagent found? A: For each reactant the tool divides the available moles by that reactant's stoichiometric coefficient, giving the "moles of reaction" each could drive. The reactant that supports the fewest moles of reaction is the limiting reagent. Theoretical yield of the product is then (moles of reaction from the limiting reagent) x (product coefficient) x (product molar mass). Q: What is percent yield and why is it rarely 100%? A: Percent yield = (actual yield / theoretical yield) x 100. It is nearly always below 100% because of side reactions, incomplete reaction, product lost during transfer or purification, and measurement error. A yield above 100% signals impurities in the product, moisture absorption, or a calculation error. Q: How do I use the dilution mode? A: The dilution formula C1V1 = C2V2 states that the moles of solute are conserved when you add solvent. Enter your stock concentration C1 (mol/L), the aliquot volume V1 (mL), and the target concentration C2. The tool returns the final volume V2, from which you can calculate how much solvent to add (V2 minus V1). Q: What units does the ideal gas calculator use? A: Pressure is in kilopascals (kPa), volume in litres (L), temperature in kelvin (K), and amount in moles (mol). R = 8.314 kPa·L/(mol·K). Standard temperature and pressure (STP) is 0 °C and 101.325 kPa, giving a molar volume of 22.414 L/mol. Standard ambient temperature and pressure (SATP) is 25 °C and 100 kPa, giving 24.789 L/mol. #### Atom Economy Calculator URL: https://geratools.com/atom-economy-calculator Free atom economy calculator. Compute AE%, E-factor, Process Mass Intensity, Reaction Mass Efficiency and check mass balance for any balanced equation. Enter molecular formulas with coefficients and get instant step-by-step working. 100% client-side — nothing is uploaded. How to use: 1. Choose a green chemistry metric: Select atom economy, E-factor, PMI, RME or mass balance from the mode dropdown. 2. Enter molecular formulas and coefficients: Type each compound formula (e.g. C6H5OH, NaCl) and its stoichiometric coefficient from the balanced equation. 3. Mark the desired product: Use the radio button to indicate which compound is the target product — all others count as reactants or byproducts. 4. Read the result and working: The tool shows the AE percentage with a colour-coded bar and full step-by-step working you can copy. FAQ: Q: What is atom economy and why does it matter? A: Atom economy (AE), introduced by Barry Trost in 1991, measures what fraction of the mass of all reactants ends up in the desired product. The formula is AE = (MW of desired product x coefficient) / (sum of MW x coefficient for all species in the balanced equation) x 100. A high AE means fewer atoms are wasted as byproducts, which reduces raw-material costs, lowers waste-treatment burden and improves the environmental profile of a process. Atom economy is a theoretical maximum — it assumes 100% yield and stoichiometric quantities — so it measures the inherent efficiency of the reaction pathway itself. Q: What is the difference between atom economy and percent yield? A: Atom economy is a property of the balanced equation and is independent of how the reaction is run. It tells you the best possible fraction of starting-material mass that can end up in the product. Percent yield, by contrast, measures what fraction of the theoretical yield you actually obtained in a given experiment. A reaction can have high AE but low percent yield (e.g. poor reaction conditions), or low AE but high percent yield (e.g. the reaction goes to completion but generates a lot of byproduct). Reaction Mass Efficiency (RME) combines both: RME = (actual product mass / total reactant mass used) x 100, so RME is always less than or equal to AE. Q: What is the E-factor and how is it calculated? A: The E-factor (environmental factor), introduced by Roger Sheldon in 1992, equals the mass of waste generated divided by the mass of desired product: E = waste (kg) / product (kg). Water is usually excluded unless it is hazardous. Typical values range from 0.1 to 5 for bulk chemicals, 5 to 50 for fine chemicals, and 25 to 100 or higher for pharmaceuticals. A lower E-factor is better; an ideal green process has E = 0. Q: What is Process Mass Intensity (PMI)? A: PMI = total mass of all materials used (reactants, reagents, solvents, catalysts) / mass of desired product. It differs from E-factor in including the product mass in the numerator, so PMI = E-factor + 1 when water is treated consistently. The ACS Green Chemistry Institute Pharmaceutical Roundtable uses PMI as its primary sustainability metric, targeting PMI ≤ 100 for pharmaceutical synthesis. A PMI of 1 would be a theoretical perfect process with no waste. Q: Which reactions have inherently high atom economy? A: Addition reactions are ideal — all atoms from both reactants appear in a single product (AE = 100%). Rearrangement reactions also have AE = 100%. Substitution reactions typically have AE of 50 to 80% because a leaving group is lost. Elimination reactions have low AE because a small molecule (e.g. water or HBr) is released as a byproduct. Multi-step syntheses multiply the AE values together, which is why step count reduction is central to green chemistry. Q: Does atom economy account for catalysts or solvents? A: In the standard Trost definition, atom economy uses only the stoichiometric reactants and products from the balanced equation — catalysts are regenerated and not consumed, so they are excluded. Solvents are likewise excluded from AE. However, catalysts and solvents often dominate the real-world waste stream, which is exactly why E-factor and PMI (which include all materials) are complementary metrics to AE. Use all five metrics together for a complete green-chemistry picture. #### Graham's Law of Effusion Calculator URL: https://geratools.com/grahams-law-calculator Free Graham's Law calculator. Instantly compute effusion rate ratios, individual effusion rates, or identify an unknown gas by molar mass. Includes 20 common gas presets (H2, O2, CO2, SF6 and more). Runs entirely in your browser. How to use: 1. Choose what to solve for: Select one of five targets: the rate ratio (r1/r2), Rate 1, Rate 2, Molar mass M1, or Molar mass M2. The unknown field is hidden; fill in the remaining values. 2. Pick a gas preset or enter a molar mass: Use the preset dropdown to auto-fill the molar mass for 20 common gases (H2, O2, CO2, SF6, etc.), or type any molar mass in g/mol directly. 3. Enter rates if required: When solving for a rate or molar mass, enter the known effusion rate(s) in your preferred unit (mol/s, mol/min, L/s, L/min, or molecules/s). 4. Read the result and working: The answer appears with the full formula substitution so you can follow every step. Hit Copy to take the value elsewhere. FAQ: Q: What is Graham's Law of Effusion? A: Graham's Law states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass: r1/r2 = sqrt(M2/M1). Formulated by Scottish chemist Thomas Graham in 1848, it follows directly from the kinetic-molecular theory of gases — lighter molecules move faster at the same temperature, so they escape through a small orifice more quickly. Q: What is the difference between effusion and diffusion? A: Effusion is the process of gas molecules passing through a tiny hole (or porous barrier) into a vacuum or lower-pressure region. Diffusion is the spreading of gas molecules through another gas. Graham's Law strictly describes effusion, but the same square-root relationship applies approximately to diffusion under similar conditions (equal temperature and pressure, ideal gases). Q: How do I find the molar mass of an unknown gas with this tool? A: Select "Molar mass of Gas 1 (M1)" or "Molar mass of Gas 2 (M2)" from the Solve-for dropdown. Enter the molar mass of the known reference gas, then enter both measured effusion rates (in any consistent unit). The calculator rearranges to M1 = M2 * (r2/r1)^2 or M2 = M1 * (r1/r2)^2 and displays the result. This technique was historically used to identify radioactive uranium hexafluoride isotopologues during isotope separation. Q: How does effusion time relate to rate? A: Effusion rate and effusion time are reciprocally related: if a gas effuses at twice the rate, it takes half the time to transfer the same number of molecules. The time form of Graham's Law is t1/t2 = sqrt(M1/M2) — note the molar masses are in the opposite order compared to the rate form. The note shown below the result box reminds you of this distinction. Q: Does Graham's Law work for all gases? A: Graham's Law assumes ideal gas behaviour — molecules are point masses with no intermolecular attractions, and the only energy is translational kinetic energy. Real gases deviate at high pressure or low temperature. For the highly accurate isotope-separation calculations used in uranium enrichment, more refined models (e.g., including the van der Waals correction) are used, but for typical chemistry problems and educational purposes Graham's Law is very accurate at near-ambient conditions. Q: Why is H2 so much faster than other gases? A: Hydrogen (H2, M = 2.016 g/mol) is by far the lightest diatomic gas. Compared with oxygen (O2, M = 32 g/mol), the rate ratio is sqrt(32/2.016) ≈ 3.98 — hydrogen effuses about four times faster. Compared with sulfur hexafluoride (SF6, M = 146 g/mol), the ratio rises to sqrt(146/2.016) ≈ 8.51. This is why hydrogen leaks spread so quickly and why hydrogen-filled pressure vessels require special attention to seal integrity. ### Physics #### Crossbow Kinetic Energy Calculator URL: https://geratools.com/crossbow-kinetic-energy Free crossbow kinetic energy calculator. Enter total bolt weight in grains and speed in fps to compute kinetic energy in ft-lbs and momentum in slug-fps, with energy guidelines showing which game size the setup is suited to. How to use: 1. Weigh your bolt: Enter the complete bolt weight in grains, including the broadhead or field point, insert, and nock, not just the shaft. 2. Enter the speed: Type the bolt speed in feet per second, taken from your crossbow's rating or a chronograph reading for accuracy. 3. Read the energy and tier: The calculator returns kinetic energy in ft-lbs, momentum in slug-fps, and the game-size tier your setup is suited to. FAQ: Q: What is the kinetic energy formula for a crossbow bolt? A: Kinetic energy in foot-pounds equals bolt weight in grains times velocity in fps squared, divided by 450,240. The constant folds in the 7,000 grains per pound conversion and the gravitational factor, giving energy directly in ft-lbs. Q: How much kinetic energy do I need to hunt deer? A: Most archery guidelines call for at least 25 to 41 ft-lbs for deer-sized game. Modern crossbows easily exceed this, often producing 90 to 130 ft-lbs, so energy is rarely the limiting factor — shot placement and broadhead choice matter more. Q: What is momentum and why does it matter? A: Momentum is mass times velocity and, expressed in slug-fps, is a strong predictor of penetration. A heavier, slower bolt can carry more momentum than a light, fast one at the same energy, which is why many bowhunters favour heavier arrows for deep penetration on large game. Q: Should I include the broadhead weight? A: Yes. Always weigh the complete arrow you will actually shoot, including the broadhead or point, insert, wraps, and nock. The broadhead alone is typically 100 to 150 grains and significantly affects total energy and momentum. Q: Does higher energy guarantee an ethical kill? A: No. Energy is only one factor. A well-placed shot with a sharp, properly tuned broadhead at an appropriate range is far more important. Excess energy cannot compensate for poor placement, and most jurisdictions also set minimum equipment requirements you must meet. #### Newtonian Telescope Collimation Offset Calculator URL: https://geratools.com/telescope-collimation-offset-calculator Enter primary focal length, secondary minor axis, and focuser-to-axis distance to compute the exact secondary mirror offset needed for correct, even illumination of the focal plane. Built for Dobsonian and Newtonian owners. How to use: 1. Enter the optical figures: Type the primary mirror focal length and the secondary mirror minor axis, both in millimetres, from your telescope's specification. 2. Add the geometry distances: Enter the distance from the focuser drawtube axis to the optical axis (the tube radius plus drawtube intrusion), used to size the offset. 3. Read the offset: The tool returns the total secondary offset and its split into away-from-focuser and toward-primary components for placement. FAQ: Q: Why does the secondary mirror need an offset at all? A: The light cone from the primary converges, so the cross-section is wider on the side nearer the primary than on the side nearer the focuser. Offsetting the elliptical secondary away from the focuser and toward the primary centres the cone on the mirror and illuminates the focal plane evenly. Q: What is the formula for the offset? A: The standard approximation is offset = secondary minor axis / (4 × focal ratio), where focal ratio is primary focal length divided by aperture. The offset is applied equally in two directions: away from the focuser and toward the primary mirror. Q: Do I offset in one direction or two? A: Two. The full offset value is applied both away from the focuser and toward the primary mirror. Many people quote the single-axis figure, so always check whether a number means the per-axis offset or the diagonal total. Q: Is offset important for fast scopes? A: Yes. Offset scales inversely with focal ratio, so an f/4 Newtonian needs roughly twice the offset of an f/8. For slow scopes above f/8 the offset is often small enough to ignore in practice. Q: Does the focuser-axis distance change the offset? A: Not the offset magnitude itself, which depends on minor axis and focal ratio. That distance matters for confirming the secondary is large enough to fully illuminate the field, which this tool also reports as a sanity check. #### Projectile Motion Calculator URL: https://geratools.com/projectile-motion-calculator Free projectile motion calculator. Enter any two of launch speed, angle, range, max height or flight time to solve for all remaining quantities. Shows step-by-step working, velocity components and an interactive parabolic trajectory chart. 100% browser-based. How to use: 1. Choose which two values you know: Pick a pair from the dropdown — launch speed + angle is the classic starting point, but you can also start from range + time, angle + height, and seven other combinations. 2. Enter the two known values: Type your numbers in the two fields that appear. Units are shown next to each label. 3. Adjust gravity if needed: Earth defaults to 9.81 m/s². Use the preset buttons for the Moon (1.62), Mars (3.72) or Jupiter (24.8), or type any value. 4. Read all five quantities plus velocity components: Launch speed, angle, flight time, max height and range appear instantly, highlighted in blue. The horiz/vert velocity components appear below. 5. Inspect the working and chart: Scroll down for the numbered derivation steps and the parabolic trajectory chart — hover any point for its exact x/y position. FAQ: Q: What formulas does this calculator use? A: For launch and landing at the same height with no air resistance: vx = v0*cos(theta), vy = v0*sin(theta), time of flight T = 2*vy/g, max height H = vy^2/(2g), range R = v0^2*sin(2*theta)/g. The calculator inverts these to solve for any two unknowns when the other three are constrained. Q: Which launch angle gives the greatest range? A: 45 degrees gives the maximum horizontal range on level ground with no drag, because sin(2*theta) reaches its peak of 1 at 2*theta = 90 degrees. Complementary angle pairs such as 30 and 60 degrees produce equal range because sin(60) = sin(120). Q: Why do 30 and 60 degrees give the same range? A: Range is proportional to sin(2*theta). Because sin(60 degrees) = sin(120 degrees), and 2*30 = 60 while 2*60 = 120, both angles share the same sine value and therefore the same range. The 60-degree shot travels higher and stays in the air longer, but lands at the same spot. Q: Is air resistance included? A: No. This is the idealised vacuum model taught in introductory physics. Real trajectories shorten at high speeds because drag decelerates the projectile — the effect is negligible at low speeds (a tennis ball gently thrown) but substantial at high speeds (a golf ball or bullet). Q: How does solve-for-any-variable work? A: Each pair of known quantities uniquely determines the remaining three through algebraic inversion of the standard kinematic equations. For example, given range R and flight time T, horizontal velocity is simply R/T and vertical initial velocity is g*T/2, from which angle and speed follow directly. Q: How do I model the Moon or Mars? A: Change gravity to 1.62 m/s^2 for the Moon or 3.72 m/s^2 for Mars using the preset buttons or by typing the value. Lower gravity means longer flight, greater height and more range for the same launch. At 1.62 m/s^2 a 20 m/s, 45-degree throw travels about 250 m instead of 40 m on Earth. #### Pressure at Depth Calculator URL: https://geratools.com/pressure-at-depth-calculator Free hydrostatic pressure calculator. Enter depth and fluid to get gauge and absolute pressure instantly. Supports seawater, fresh water, mercury and custom fluids. Runs fully in your browser — no data is uploaded. How to use: 1. Choose a direction: Select "Depth → Pressure" to find the pressure at a known depth, or "Pressure → Depth" to find how deep you must go to reach a target pressure. 2. Enter the depth (or target pressure): Type the depth in metres, feet or centimetres. Switch to solve-for-depth mode and enter a target absolute pressure instead if you need the inverse. 3. Pick the fluid: Choose seawater (1 025 kg/m³), fresh water (998 kg/m³), brackish water, mercury, engine oil, or enter a custom density. 4. Read gauge and absolute pressure: The calculator shows both gauge pressure (the extra pressure due solely to the fluid column) and absolute pressure (gauge plus surface atmospheric pressure), in whichever unit you select. 5. Adjust advanced settings if needed: Expand the advanced panel to change surface pressure (e.g. for a vessel pressurised above 1 atm) or local gravitational acceleration (e.g. 9.832 m/s² at the poles, or lunar gravity 1.625 m/s²). FAQ: Q: What is the formula for pressure at depth? A: The standard hydrostatic equation is P = P₀ + ρgh, where P₀ is the pressure at the surface, ρ (rho) is the fluid density in kg/m³, g is gravitational acceleration in m/s², and h is the depth in metres. The term ρgh gives the gauge pressure — the extra pressure the fluid column adds. Adding P₀ gives the absolute pressure referenced to a perfect vacuum. Q: How much does pressure increase per metre in seawater? A: Seawater has a density of approximately 1 025 kg/m³. At standard gravity (9.806 65 m/s²), each metre of seawater adds ρg ≈ 1 025 × 9.807 ≈ 10 052 Pa ≈ 10.05 kPa ≈ 0.1 bar ≈ 1.46 psi of gauge pressure. A common rule of thumb is "roughly 1 atm (≈ 10 m seawater)", which is only approximate — 10 m seawater ≈ 0.993 atm gauge. Q: What is the difference between gauge pressure and absolute pressure? A: Gauge pressure is measured relative to the ambient surface pressure (the zero point is atmospheric pressure). Absolute pressure is measured relative to a perfect vacuum, so it equals gauge pressure plus the surface pressure. A diver at 10 m in seawater experiences roughly 2 atm absolute (1 atm surface + 1 atm from the water column) but only 1 atm gauge. Q: Does salinity or temperature affect underwater pressure? A: Yes. Seawater density ranges from about 1 020 to 1 030 kg/m³ depending on salinity and temperature. Colder, saltier water is denser and creates slightly higher pressure at the same depth. The calculator uses 1 025 kg/m³ as the ISO/NOAA representative value; for precise oceanographic work you can enter a custom density based on in-situ CTD measurements and the UNESCO EOS-80 equation of state. Q: How deep is the Mariana Trench and what is the pressure there? A: Challenger Deep in the Mariana Trench reaches approximately 10 935 m. At that depth in seawater (ρ = 1 025 kg/m³), gauge pressure is about 109 900 kPa ≈ 1 086 atm ≈ 15 950 psi. Absolute pressure (adding 1 atm surface) is approximately 1 087 atm — roughly 1 000 times the pressure felt at sea level. The reference table in the calculator shows this and other famous depths. Q: Can I use this calculator for non-water fluids like mercury or oil? A: Yes. The hydrostatic formula P = ρgh applies to any static fluid. Mercury (ρ ≈ 13 546 kg/m³) produces about 13 times the pressure of water at the same depth — a 760 mm column of mercury equals exactly 1 atm (the origin of mmHg as a pressure unit). Engine oil at ≈ 870 kg/m³ produces slightly less pressure than fresh water. Select the appropriate fluid or enter a custom density for any liquid. #### Gas Density Calculator URL: https://geratools.com/gas-density-calculator Free gas density calculator using the ideal gas law (rho = PM/RT). Enter pressure, temperature and molar mass for 16 preset gases (air, CO2, H2, CH4 and more) or custom gas. Solve for density, pressure or temperature. Shows step-by-step working and a reference table for STP/NTP/room conditions. 100% client-side. How to use: 1. Choose what to solve for: Pick "Gas density", "Pressure", or "Temperature" from the Solve for dropdown. The two known quantities become inputs; the third is computed. 2. Select your gas: Choose from 16 preset gases (dry air, N2, O2, CO2, H2, He, CH4, Ar, and more) or select Custom and type any molar mass in g/mol. 3. Enter pressure and temperature: Type the pressure in any unit (Pa, kPa, bar, atm, psi, mmHg) and the temperature in K, °C, or °F. The calculator converts everything to SI before computing. 4. Read the result and working: The result appears instantly. Expand the Working section to see each algebraic step. Hit Copy to paste the full working into a document or report. 5. Check standard-condition densities: The reference table below the result shows the density of your chosen gas at STP (IUPAC 2014), old STP (0 °C / 1 atm), NTP, and room temperature for quick sanity checks. FAQ: Q: What formula does this calculator use? A: It uses the ideal gas law rearranged for density: rho = (P x M) / (R x T), where P is absolute pressure in Pa, M is molar mass in kg/mol, R = 8.31446 J per mol per K (universal gas constant, CODATA 2018), and T is absolute temperature in K. The same equation rearranges to P = (rho x R x T) / M and T = (P x M) / (rho x R) for the other two solve modes. Q: What is the density of air at room temperature? A: Dry air (M = 28.97 g/mol) at 25 degrees C and 1 atm (101325 Pa) has a density of approximately 1.184 kg/m3. At 20 degrees C (NTP) it is about 1.204 kg/m3, and at 0 degrees C (old STP) about 1.293 kg/m3. This calculator reproduces all three values in its reference table. Q: Does the formula work for all gases? A: It works well for gases well above their boiling point and at pressures well below the critical pressure (roughly below 5-10 MPa for most industrial gases). For high-pressure pipelines, near-critical conditions, or liquefied gases, a real-gas equation of state such as van der Waals or Peng-Robinson gives more accurate results. For engineering-grade accuracy at elevated pressure, apply a compressibility factor Z: rho = PM / (ZRT). Q: Why do I need to enter molar mass? A: The ideal gas law itself (PV = nRT) treats every gas the same. Molar mass M connects the amount of substance (n, in mol) to the actual mass (m = nM). Without M the formula cannot distinguish between a heavy molecule like CO2 (44 g/mol, density 1.96 kg/m3 at STP) and a light one like hydrogen H2 (2.016 g/mol, density 0.090 kg/m3 at STP). Selecting a preset gas fills in the correct IUPAC molar mass automatically. Q: What is STP and how does it differ from NTP? A: STP (Standard Temperature and Pressure) is defined by IUPAC since 2014 as 0 degrees C (273.15 K) and 100 kPa. The older pre-1982 STP used 1 atm (101.325 kPa) instead of 100 kPa, giving a slightly higher density. NTP (Normal Temperature and Pressure) is a US convention using 20 degrees C and 1 atm and is common in HVAC and compressed-gas specifications. The reference table in the calculator shows all three alongside room temperature (25 degrees C / 1 atm). Q: Can I use this for gas mixture density? A: Yes, as long as you know the mixture molar mass. For a mixture, the effective molar mass is the mole-fraction-weighted average of the component molar masses: M_mix = sum(y_i x M_i) where y_i is the mole fraction of component i. Enter this value using the Custom molar mass option. For example, a 60/40 (by moles) methane/propane mix has M_mix = 0.60 x 16.04 + 0.40 x 44.10 = 27.26 g/mol. #### Thermal Expansion Calculator URL: https://geratools.com/thermal-expansion-calculator Free thermal expansion calculator. Find dimensional change, initial size or final temperature for linear, area and volumetric expansion. Covers 30 materials with real coefficient of thermal expansion (CTE) values. 100% browser-based — nothing is uploaded. How to use: 1. Choose expansion type: Select Linear (ΔL), Area (ΔA) or Volume (ΔV) depending on whether you need one-dimensional, two-dimensional or three-dimensional expansion. 2. Pick or enter a material: Select from 30 common engineering materials. Choose Custom to type any coefficient of thermal expansion (CTE) in units of 10⁻⁶ per °C. 3. Enter the initial size and temperatures: Type the original length, area or volume and the starting and final temperatures. The calculator immediately shows the expansion, final dimension and thermal strain. 4. Solve in reverse if needed: Switch Solve For to find the initial dimension from a known expansion, or to find the temperature needed to produce a target dimensional change. FAQ: Q: What is the formula for thermal expansion? A: For linear expansion the standard formula is ΔL = α · L₀ · ΔT, where α is the material's coefficient of thermal expansion (CTE) in 1/°C, L₀ is the original length and ΔT is the temperature change. Area expansion uses ΔA = 2α · A₀ · ΔT and volumetric expansion uses ΔV = 3α · V₀ · ΔT. The factors 2 and 3 come from treating isotropic expansion as the sum of independent directional strains. Q: What is CTE and where do I find it? A: CTE (coefficient of thermal expansion) is a material property that describes how much a unit length changes per degree of temperature change. Values are in 10⁻⁶/°C (microstrain per °C) and are tabulated in engineering data books, ASTM standards and manufacturer datasheets. The calculator includes verified values for 30 common materials from aluminium (23.1 × 10⁻⁶/°C) to fused quartz (0.59 × 10⁻⁶/°C). Q: What is the difference between linear and volumetric expansion? A: Linear expansion describes how one dimension of a solid changes with temperature and is governed by the linear CTE α. Volumetric expansion describes the total change in three-dimensional size and uses an effective CTE of β = 3α for isotropic solids. Area (superficial) expansion uses β = 2α. Liquids and gases only have volumetric expansion; solids have all three. Q: Why does steel expand less than aluminium? A: The CTE is determined by the interatomic bonding energy. Metals with stronger, stiffer bonds vibrate less for a given thermal energy input, producing smaller average displacements and thus lower CTE values. Steel has a higher Young's modulus and stronger Fe–Fe bonds than aluminium, giving it a CTE of about 11.7 × 10⁻⁶/°C versus 23.1 × 10⁻⁶/°C for aluminium. This is why bimetallic strips (an aluminium–steel or brass–invar pair) curl when heated: the two layers expand at different rates. Q: What is Invar and why is its CTE so low? A: Invar (FeNi36) is an iron–nickel alloy with 36% nickel. Near room temperature its magnetic properties almost exactly cancel the normal thermal expansion, giving a CTE of only about 1.2 × 10⁻⁶/°C — roughly twenty times lower than ordinary steel. It is used in precision instruments, watch mechanisms, geodetic tapes, seismic sensors and the shadow masks of CRT screens where dimensional stability under temperature change is critical. Q: Is the thermal expansion formula valid at all temperatures? A: No. The linear formula ΔL = α · L₀ · ΔT assumes α is constant, which holds well over moderate engineering ranges (typically −50 °C to +200 °C for most metals). At very high or very low temperatures, or near phase-transition points, CTE can vary significantly with temperature. For large temperature swings, integrate the temperature-dependent CTE: ΔL = L₀ ∫α(T)dT. The calculator uses the room-temperature reference value, so treat results at extreme temperatures as estimates. #### Friction Calculator URL: https://geratools.com/friction-calculator Free friction calculator covering kinetic and static friction (F = μN), normal force on inclines (N = mg cos θ), critical slip angle (tan θ = μs), incline net force and acceleration (a = g(sin θ − μk cos θ)), and back-calculation of μ from measurements. Runs entirely in your browser. How to use: 1. Pick a calculation mode: Choose from friction force, normal force on incline, coefficient from data, incline motion, or critical slip angle. 2. Select a material preset or enter coefficients: Pick a pair such as "rubber on dry concrete" (μs=0.9, μk=0.8) or type your own μs and μk values. 3. Enter mass or normal force: For flat surfaces enter the normal force directly. For inclined surfaces enter mass and angle θ in degrees. 4. Read results and working: The primary result updates instantly. Expand "Show working" to see every formula step, and optionally copy the full working to clipboard. FAQ: Q: What is the difference between static and kinetic friction? A: Static friction (F_s) prevents an object from starting to move. It is self-adjusting up to a maximum of μs × N. Once the object moves, kinetic (sliding) friction F_k = μk × N takes over. Because μk is almost always less than μs, less force is needed to keep an object sliding than to start it moving. Q: What do the formulas F_k = μk × N and F_s ≤ μs × N mean? A: N is the normal force — the force the surface pushes back perpendicular to itself. Multiplying N by the dimensionless friction coefficient gives the friction force. The kinetic formula is exact; the static formula gives the maximum value before motion begins. Q: Why does the normal force change on an incline? A: On a slope at angle θ, only the component of gravity perpendicular to the surface acts on the surface, so N = mg cos θ. The parallel component mg sin θ tries to slide the object down, while kinetic friction μk × N opposes it. Q: How is the critical slip angle calculated? A: At the exact angle where the object is on the verge of sliding, the driving force equals maximum static friction: mg sin θ = μs × mg cos θ. Cancelling mg gives tan θ = μs, so θ = arctan(μs). This is why a steeper hill is harder to stand on. Q: How do I find μ from an experiment? A: Measure the friction force F and the normal force N directly (e.g. with a spring scale). Then μ = F / N. The calculator has a dedicated "coefficient from data" mode that does this calculation and shows the steps. Q: Is friction the same in all directions? A: Coulomb (dry) friction — modelled here — is isotropic: the magnitude is the same regardless of sliding direction. Anisotropic friction (e.g. brush contacts, grain direction in wood) requires more advanced models and is not covered by the standard μN formula. #### Power Physics Calculator URL: https://geratools.com/power-physics-calculator Free multi-formula physics power calculator. Covers mechanical, electrical, hydraulic, rotational and radiation power. Solve for any variable, see step-by-step working, choose your units. Runs 100% in your browser. How to use: 1. Pick a formula domain: Use the "Formula / domain" dropdown to choose the relevant equation: mechanical (P = W/t or P = Fv), rotational (P = τω), electrical (P = VI, P = I²R, P = V²/R), hydraulic (P = ρgQh), gravitational (P = mgh/t), or radiation intensity. 2. Select what to solve for: Each mode has its own "Solve for" selector. Pick the unknown quantity — the inputs for the other variables appear automatically. 3. Enter values and choose units: Type your known values and pick the unit from the adjacent dropdown. SI units are the default, but imperial and practical alternatives (rpm, kWh, hp, lbf, mph) are available throughout. 4. Read the result and working: The answer appears instantly in engineering notation. Expand the "Working" section to see every substitution step, then hit "Copy" to export the working to your clipboard. FAQ: Q: What is the SI unit of power and how is it defined? A: The SI unit of power is the watt (W), named after James Watt. One watt equals one joule of energy transferred per second (1 W = 1 J/s). Larger multiples — kilowatt (kW = 1 000 W), megawatt (MW = 1 000 000 W) — are common in engineering. The imperial unit horsepower (1 hp = 745.7 W) is still widely used for engines and motors. Q: How does the calculator handle the formula P equals W divided by t? A: P = W/t is the most fundamental definition of power: divide the total energy (work done, in joules) by the elapsed time (in seconds) to get the average power in watts. The calculator also rearranges the formula so you can solve for energy (W = P × t) or time (t = W/P). It converts the result to kWh, kcal, and hours automatically. Q: When do I use P equals F times v versus P equals W divided by t? A: P = Fv is the instantaneous mechanical power for an object experiencing a constant force F (newtons) moving at velocity v (m/s). It is most useful for engines, vehicles, and conveyor belts where you know the thrust force and speed rather than the total energy over a period. P = W/t is better when you know the total energy released or consumed over a measured time interval. Q: What is P equals tau times omega and when is it used? A: P = τω is the rotational analogue of P = Fv. Torque τ (in N·m) is the rotational equivalent of force, and angular velocity ω (in rad/s) is the rotational equivalent of linear velocity. Engine power is almost always measured this way: a dynamometer measures torque at a given rpm, and P = τω gives shaft power. The calculator accepts rpm directly and converts it to rad/s internally. Q: Which electrical power formula should I use — P = VI, P = I²R, or P = V²/R? A: All three are equivalent via Ohm's law (V = IR), but each is convenient when certain quantities are known. Use P = VI when you have both voltage and current readings (e.g. a multimeter measurement). Use P = I²R (Joule heating) when current and resistance are known — common for resistors, heating elements, and cable sizing. Use P = V²/R when voltage and resistance are known — typical for load calculations at a fixed supply voltage. Q: What does the inverse-square law mode calculate? A: The radiation intensity mode implements the inverse-square law: I = P / (4πr²). For a point source radiating isotropically (equally in all directions), intensity falls off with the square of distance. Doubling the distance from a source reduces intensity to one-quarter. This applies to sound, light, radio waves, and radiation. The calculator lets you solve for total power P, intensity I at a given distance r, or the distance r at which a given intensity is reached. #### Banking Angle Calculator URL: https://geratools.com/banking-angle-calculator Free banking angle calculator using tan(θ) = v²/(r·g). Solve for angle, ideal speed, or curve radius. Shows centripetal acceleration, normal-force ratio, lateral force, and full step-by-step working. 100% client-side. How to use: 1. Choose what to solve for: Select Banking Angle, Ideal Speed, or Curve Radius from the "Solve for" dropdown. 2. Enter the known values: Type the speed (choose m/s, km/h, or mph), the curve radius in metres, or the banking angle in degrees — whichever two you know. 3. Add vehicle mass (optional): Enter the vehicle mass in kg to get lateral force and weight breakdowns in addition to the angle result. 4. Read primary and secondary results: The tool instantly shows the solved quantity plus centripetal acceleration, normal-force ratio, and orbital period. 5. Expand step-by-step working: Click "Show step-by-step working" to see every substitution and intermediate value with its unit. FAQ: Q: What is the banking angle formula? A: The ideal banking angle for a frictionless curve is given by tan(θ) = v²/(r·g), where v is the vehicle speed in m/s, r is the curve radius in metres, and g = 9.81 m/s². Rearranging gives v = sqrt(r·g·tan(θ)) for ideal speed, or r = v²/(g·tan(θ)) for radius. Q: What does "ideal banking angle" mean? A: At the ideal angle, the horizontal component of the normal force exactly supplies the centripetal force needed. No friction is required, so the result is independent of vehicle mass and tyre compound — it is purely a function of speed, radius, and gravity. Q: Why is the N/W ratio always greater than 1 on a banked curve? A: The normal force N must support both the weight component (vertical) and the centripetal requirement (horizontal). The ratio N/W = 1/cos(θ), which is always > 1 for any non-zero banking angle. At 45° the normal force is 1.41 times body weight; at 60° it reaches 2×. Q: How does banking relate to centripetal force? A: On a frictionless bank the centripetal acceleration a_c = v²/r is provided entirely by the horizontal component of the normal force. The vertical component balances gravity, so tan(θ) = a_c/g. This is the same physics that governs aircraft banking in a coordinated turn. Q: What is superelevation and how does it relate to banking angle? A: Superelevation (e) is the cross-slope of a road expressed as a rate (e.g. 0.08 m/m or 8%). It is related to banking angle by e = tan(θ). Transport authorities such as AASHTO and UK Highways England specify maximum superelevation rates (typically 7–10%) to ensure vehicles remain stable across a range of speeds, not just the design speed. Q: Does friction matter in the real world? A: Yes. This calculator models the frictionless ideal, which gives the design speed at which no lateral friction is needed. In practice roads are designed for a range of speeds, and tyre friction handles the difference. A vehicle travelling faster than the ideal speed relies on friction pointing up the slope; slower than ideal, friction points down. Q: Can I use this for aircraft bank angle calculations? A: Yes. For a coordinated (ball-centred) turn in level flight the load factor n = 1/cos(θ) and the turn radius r = v²/(g·tan(θ)) — the same formula this calculator uses. Enter true airspeed in m/s and the desired turn radius to find the required bank angle, or enter bank angle and speed to find the turn radius. #### Orbital Velocity Calculator URL: https://geratools.com/orbital-velocity-calculator Calculate circular orbital velocity v = sqrt(GM/r), escape velocity, orbital period and geostationary orbit altitude for any planet or star. Solve forward (velocity from altitude) or backward (altitude from velocity). Presets for Earth, Moon, Mars, Jupiter and the Sun. Runs entirely in your browser. How to use: 1. Choose the central body: Pick a preset (Earth, Moon, Mars, Jupiter, Saturn, Sun) or type any mass in kg directly. 2. Select a mode: Use "Find orbital velocity from altitude" to get speed, period and escape velocity for a given orbit height. Use "Find orbital radius from velocity" to reverse-solve for the required altitude. Use "Geostationary orbit" to get the unique altitude where the satellite hovers above one spot. 3. Enter the altitude or velocity: Type the altitude above the surface in km, or the target velocity in m/s. Preset buttons fill in well-known orbits like ISS (408 km), GPS (20 200 km) and GEO (35 786 km). 4. Read the results: The tool instantly shows orbital velocity, escape velocity, orbital period, orbital radius and specific orbital energy. Copy the full result with one click. FAQ: Q: What is orbital velocity? A: Orbital velocity is the exact speed at which a satellite must travel tangentially to maintain a stable circular orbit at a given altitude. Too slow and gravity pulls the satellite inward; too fast and it climbs to a higher orbit or escapes entirely. Q: What formula is used? A: The circular orbital velocity formula is v = sqrt(GM / r), where G = 6.6743 x 10^-11 m^3 kg^-1 s^-2 is the gravitational constant, M is the central body mass in kg and r is the orbital radius (body radius plus altitude) in metres. Q: How is escape velocity related to orbital velocity? A: At any given orbital radius, the escape velocity is exactly sqrt(2) times the circular orbital velocity, so about 1.414 times faster. For a low Earth orbit at 408 km, orbital velocity is roughly 7 670 m/s and escape velocity from that point is about 10 845 m/s. Q: What altitude is needed for a geostationary orbit? A: Above Earth, the geostationary radius works out to about 42 164 km from the centre, which puts the satellite roughly 35 786 km above the surface. At that altitude the orbital period matches Earth's sidereal rotation (86 164.1 s), so the satellite appears stationary over a fixed point on the equator. Q: Does orbital velocity change with altitude? A: Yes. Higher altitude means a larger orbital radius r, so v = sqrt(GM/r) decreases. Counterintuitively, to raise an orbit you first fire the engine to speed up, which stretches the orbit to an ellipse; you then fire again at the far end to circularise at the higher altitude — the satellite ends up moving slower overall, but you had to speed up to get there. Q: What is specific orbital energy? A: Specific orbital energy (energy per unit mass) is E = -GM / (2r) in joules per kilogram. It is always negative for a bound orbit — the more negative it is, the more tightly bound the satellite is to the central body. At the escape threshold E would equal zero. #### Wave Speed Calculator URL: https://geratools.com/wave-speed-calculator Free wave speed calculator using v = f × λ. Solve for wave speed, frequency, wavelength, or period for sound, light, or any wave. Shows full working and secondary quantities. Runs entirely in your browser. How to use: 1. Choose what to solve for: Pick wave speed, frequency, wavelength, or period from the dropdown — the tool rearranges v = f × λ for you. 2. Select a medium or enter a custom speed: Use a preset (sound in air at 343 m/s, sound in water at 1481 m/s, light in vacuum at 299,792,458 m/s) or type any wave speed. 3. Enter the known values: Fill in the remaining quantities and the result appears instantly with step-by-step working. 4. Read secondary quantities: The panel below the result also shows period (T = 1 ÷ f), angular frequency (ω = 2πf), and wave number (k = 2π ÷ λ). FAQ: Q: What is the wave speed formula? A: Wave speed equals frequency times wavelength: v = f × λ. Rearranged, f = v ÷ λ and λ = v ÷ f. Period T = 1 ÷ f, so you can also write v = λ ÷ T. Q: What is the speed of sound in air? A: At about 20 °C and sea-level pressure the speed of sound in air is approximately 343 m/s (1235 km/h or 1125 ft/s). It rises by roughly 0.6 m/s for every 1 °C increase in temperature, so at 0 °C it is about 331 m/s. Q: How does wave speed change in different materials? A: Wave speed depends on the medium. Sound travels faster in denser, stiffer materials — about 1481 m/s in water and around 5120 m/s in steel. Light slows when it enters a material; its speed in a medium is c divided by the refractive index (n), giving roughly 200,000 km/s in glass. Q: What is wavelength? A: Wavelength (λ) is the distance between two consecutive points in the same phase of a wave — for example, crest to crest or trough to trough. It is measured in metres. A 440 Hz musical note (concert A) travelling through air has a wavelength of about 0.78 m. Q: What is period and how does it relate to frequency? A: Period (T) is the time for one complete wave cycle, measured in seconds. Frequency (f) is the number of cycles per second, measured in hertz (Hz). They are reciprocals: T = 1 ÷ f and f = 1 ÷ T. A 440 Hz note has a period of roughly 0.00227 s (2.27 ms). Q: What is angular frequency and wave number? A: Angular frequency ω = 2πf is the rate of oscillation in radians per second, useful in equations for simple harmonic motion and electromagnetic waves. Wave number k = 2π ÷ λ is the spatial equivalent — the number of wave cycles per 2π metres — and appears in the full wave equation y = A sin(kx − ωt). ### Electronics #### Three-Phase Voltage Imbalance Calculator URL: https://geratools.com/ac-voltage-imbalance-calculator Computes NEMA MG1 percent voltage unbalance as the maximum deviation from the average divided by the average, times 100, from three measured line-to-line voltages, and returns the motor derating factor from NEMA MG1 for the calculated unbalance. Runs entirely in your browser. How to use: 1. Measure the three line voltages: With a meter, record the three line-to-line voltages of the supply, for example L1 to L2, L2 to L3, and L3 to L1, at the motor terminals. 2. Enter the readings: Type the three measured voltages into the fields. The order does not matter because the method uses the average and the largest deviation. 3. Read the unbalance and derating: The tool shows the average, the maximum deviation, the percent unbalance, and the NEMA MG1 derating factor you must apply to the motor. FAQ: Q: What is the NEMA voltage unbalance formula? A: Percent voltage unbalance equals the maximum deviation of any line voltage from the average line voltage, divided by the average line voltage, multiplied by 100. The average is the mean of the three line-to-line readings. Q: How much unbalance is acceptable? A: NEMA MG1 recommends operating motors at no more than 1 percent voltage unbalance. Above 1 percent the motor must be derated, and operation above 5 percent is not recommended because the heating becomes severe and damaging. Q: Why does small voltage unbalance cause large current unbalance? A: A small voltage unbalance produces a negative-sequence voltage that drives a large negative-sequence current because motor negative-sequence impedance is low. The current unbalance is roughly 6 to 10 times the voltage unbalance, which causes localized overheating. Q: What derating does NEMA require? A: NEMA MG1 gives a derating curve: about 1.0 at 1 percent unbalance, 0.95 at 2 percent, 0.88 at 3 percent, 0.82 at 4 percent, and 0.75 at 5 percent. The motor must run below its nameplate horsepower by this factor to avoid overheating. Q: Could my readings indicate a real problem? A: Yes. Persistent unbalance above 2 to 3 percent often signals a loose connection, an unbalanced single-phase load on the same transformer, a failing utility tap, or a weak phase. Investigate the supply before the motor fails from overheating. #### Bar Exam MBE & Scaled Score Calculator URL: https://geratools.com/bar-exam-mbe-calculator Enter your estimated MBE raw score plus written MEE and MPT component scores to project a Uniform Bar Exam scaled total (out of 400) and compare it to your state's passing line, typically 260 to 270. How to use: 1. Enter your MBE raw score: Type how many of the 175 scored MBE questions you answered correctly, then the tool estimates the scaled MBE figure. 2. Add your written scores: Enter your average MEE essay score and MPT score on the 0-100 raw scale your jurisdiction uses. 3. Compare to the passing line: Set your state's UBE cut score (usually 260-270) to see whether your projected total clears it. FAQ: Q: How is the Uniform Bar Exam scored? A: The UBE total is out of 400 and is split 50/50 between the MBE and the written component. The MBE (200 points) is the scaled multiple-choice score; the written side (200 points) combines the MEE essays (30%) and the MPT (20%) of the overall exam, scaled to the MBE. Q: What is a passing UBE score? A: Passing scores are set by each jurisdiction and most fall between 260 and 270 out of 400. For example, New York requires 266, while some states use 260 and others 270. Always confirm the exact cut score with your board of law examiners. Q: How does raw MBE convert to scaled MBE? A: The NCBE equates the MBE using a statistical scaling process, so there is no fixed table. As a rough planning estimate, the scaled MBE is often close to the percentage correct mapped onto the 0-200 range, but the true conversion shifts each administration based on question difficulty. Q: How are the MEE and MPT weighted? A: Within the written half, the MEE (six essays) counts for 30% of the total exam and the MPT (two performance tasks) counts for 20%, a 3:2 ratio. Together they form the 200-point written component that is scaled to match the MBE distribution. Q: Is this calculator an official score? A: No. It is a planning estimate only. The NCBE's equating and your jurisdiction's scaling are proprietary, so your official scaled score can differ. Use this to gauge whether you are comfortably above, near, or below your target. #### Battery State of Charge (SoC) Estimator URL: https://geratools.com/battery-state-of-charge-calculator Estimate battery state of charge from open-circuit resting voltage using bundled voltage-SoC curves for flooded lead-acid, AGM, gel and LiFePO4 banks at 12V, 24V and 48V, plus a Peukert calculator for effective capacity and runtime at any discharge current. How to use: 1. Read SoC from resting voltage: Pick the battery chemistry and system voltage, then enter the open-circuit voltage measured after the bank has rested with no load or charge for several hours. 2. Apply Peukert correction: Enter rated capacity, the rated discharge time (usually 20 h), the Peukert exponent and your actual discharge current to find effective deliverable capacity and runtime. 3. Plan your reserve: Compare the two estimates and keep lead-acid above 50 percent SoC to extend cycle life; LiFePO4 can be safely cycled much deeper. FAQ: Q: How does resting voltage map to state of charge? A: Each chemistry has a characteristic open-circuit voltage curve. This tool stores a voltage-SoC table per 12V block for flooded, AGM, gel and LiFePO4 cells, scales it to your 12/24/48V bank, then linearly interpolates your measured voltage to a percentage. Q: Why must the battery rest before measuring? A: Surface charge and load voltage drop distort the reading. After charging or discharging, the terminal voltage needs 4 to 24 hours of rest with no current to settle to the true open-circuit value that correlates with SoC. Q: What is the Peukert equation? A: Peukert's law describes how a lead-acid battery delivers less capacity at higher discharge currents. Runtime t equals H times (C divided by I times H) raised to the exponent k, where C is rated capacity, H the rated hour-rate, I the current and k the Peukert exponent. Q: What Peukert exponent should I use? A: LiFePO4 and lithium banks are near 1.0 (capacity barely changes with current). Quality AGM is around 1.05 to 1.15, and flooded lead-acid ranges from about 1.1 to 1.3. Use the value from your battery datasheet when available. Q: Why is the LiFePO4 voltage curve so flat? A: Lithium iron phosphate cells hold a nearly constant voltage across most of their discharge, so voltage is a poor SoC indicator between roughly 20 and 90 percent. A coulomb-counting shunt monitor is far more accurate for lithium banks than voltage alone. #### Control Transformer Sizing Calculator URL: https://geratools.com/control-transformer-sizing Sums relay coil, pilot light, and PLC VA for steady-state load, then adds the largest single inrush to find the minimum control power transformer (CPT) VA and the next standard size (150, 250, 500 VA, 1 kVA). Built for controls electricians and panel builders. How to use: 1. Add up the sealed VA: Enter the total sealed (holding) VA of relays and contactors, the pilot lights, and the PLC plus its power supply. This is the steady-state burden the transformer carries continuously. 2. Enter the largest inrush: Find the single device with the biggest pull-in (inrush) VA — usually the largest contactor coil — and enter its inrush VA. Coil data sheets list both sealed and inrush figures. 3. Read the recommended size: The tool sizes the CPT for both the steady load and the worst-case inrush dip, then picks the larger and rounds up to the next standard rating. FAQ: Q: Why size for both sealed and inrush VA? A: A control transformer must carry the continuous sealed load forever, but it must also survive the brief inrush when a large contactor energizes without the voltage sagging so far that other devices drop out. Sizing only on sealed VA can leave the panel unable to pull in a big contactor. Q: What is the difference between sealed and inrush VA? A: Inrush (pull-in) VA is the high burden drawn for the first few cycles as a coil's magnetic field builds; sealed (holding) VA is the much smaller steady draw once it is energized. A contactor might draw 600 VA inrush but only 25 VA sealed. Q: Why does acceptable voltage dip change the size? A: During inrush the transformer voltage sags. If you can only tolerate a small dip (say 5% for electronic loads), you need a larger transformer with stiffer regulation. If 15% dip is fine because only contactors are connected, a smaller unit works. Q: What are the standard control transformer sizes? A: Common VA ratings are 50, 75, 100, 150, 200, 250, 350, 500, 750, 1000, 1500, 2000, and 3000 VA. The tool always rounds your calculated requirement up to the next standard size so you can specify a real part. Q: Should I add spare capacity? A: Yes — leave at least 25% headroom for future additions and for the fact that coils age and panels grow. The calculator gives the minimum; specifying the next size up is common practice. #### High-Leg Delta Voltage Calculator URL: https://geratools.com/high-leg-delta-voltage-calculator Computes the high-leg (wild-leg) voltage to ground on a 4-wire delta service using V = line-to-line × sin(60°), confirms the NEC orange-conductor marking rule, and checks single-pole device compatibility. Runs in your browser. How to use: 1. Choose the service voltage: Select the line-to-line voltage of the delta service, most commonly 240 V for a 120/240 V high-leg delta. 2. Optionally check a device: Enter the voltage-to-ground rating of a single-pole device to confirm it will not be overstressed if landed on the high leg. 3. Read the high-leg voltage: The tool shows the normal line-to-neutral voltage on the two good legs and the elevated high-leg voltage on phase B, plus the marking requirement. FAQ: Q: Why is the high leg higher than the other two? A: Only one transformer winding is center-tapped to create the neutral, so two legs read half the line-to-line voltage. The third leg sits at the apex of the delta triangle and measures line-to-line times the sine of 60 degrees to that center-tap neutral, which is higher. Q: What is the high-leg voltage on a 240 V delta? A: It is 240 × sin(60°), which equals 240 × 0.866, or about 208 V to ground. This is why the high leg is nicknamed the 208 V wild leg, stinger, or bastard leg on a 120/240 V delta service. Q: Which phase must be the high leg? A: NEC 408.3(F) requires the high leg to be the B phase in panelboards and switchboards where the neutral is present. It must be durably marked, conventionally with orange, so no one mistakes it for a normal 120 V phase. Q: Can I land 120 V loads on the high leg? A: No. A 120 V single-pole load connected to the high leg sees roughly 208 V to neutral and will burn out. Only the two normal legs supply 120 V; the high leg is used only for three-phase loads or 240 V line-to-line connections. Q: Does the high leg affect three-phase loads? A: No. Line-to-line voltage between all three phases is the same 240 V, so three-phase motors and 240 V loads operate normally. The elevated voltage only appears between the high leg and the grounded neutral. #### LiPo Battery Capacity & Flight Time Calculator URL: https://geratools.com/lipo-battery-capacity-calculator Enter LiPo battery capacity in mAh, average current draw in amps, and a usable-capacity factor to compute estimated flight or run time in minutes. For RC pilots and drone operators sizing batteries and planning flights. How to use: 1. Enter battery capacity: Type your LiPo pack's rated capacity in milliamp-hours, printed on the label (for example 1500 mAh). 2. Enter average current draw: Enter the average current in amps your craft pulls in flight, from a power meter, telemetry, or an estimate. 3. Read estimated time: The tool applies your usable-capacity factor and reports estimated flight or run time in minutes and seconds. FAQ: Q: How is flight time calculated? A: Time in hours equals usable capacity in amp-hours divided by average current in amps. The tool converts mAh to Ah by dividing by 1000, multiplies by the usable factor, divides by current, and converts hours to minutes. Q: Why use a usable-capacity factor instead of the full capacity? A: Discharging a LiPo to empty damages it. Pilots typically land with 20 percent left, using only about 80 percent of rated capacity. The usable factor (default 0.8) reflects this safe reserve so the estimate matches real flights. Q: What current draw should I enter? A: Use the average in-flight current, not the peak. Hovering multirotors and cruising planes draw far less than full throttle. A power meter or flight-controller telemetry gives the most accurate average; otherwise estimate from your setup. Q: Does a bigger battery always mean longer flight? A: Not proportionally. A larger pack adds weight, which raises the current needed to lift it, partly offsetting the extra capacity. There is an optimal pack size for each craft where added weight starts to cancel the gain in capacity. Q: Does this account for voltage sag or temperature? A: No. It is a capacity-versus-current estimate. Cold weather, aging cells, and heavy voltage sag reduce usable capacity, so treat the result as an upper bound and keep a safety margin. #### Medium-Voltage Cable Sizing Calculator (5–35 kV) URL: https://geratools.com/medium-voltage-cable-sizing-calculator Selects the minimum copper conductor for medium-voltage shielded cable (5/8/15/25/35 kV class) from NEC 310.60 and IEEE Std 835 ampacity values for direct-buried, conduit, and tray installations, then checks voltage drop at the maximum load current. How to use: 1. Enter load and method: Type the maximum load current and choose the installation method — direct buried, in conduit, or in cable tray — so the correct ampacity column applies. 2. Set voltage and length: Pick the voltage class from 5 to 35 kV, enter the one-way run length, and set the load power factor. 3. Read size and drop: The tool returns the smallest copper conductor that carries the load and reports the voltage drop against the 3% target. FAQ: Q: How is the conductor selected? A: The tool steps through standard MV copper sizes and picks the smallest whose ampacity for the chosen installation method meets or exceeds the load current. Ampacities follow representative NEC Table 310.60 and IEEE Std 835 values for shielded medium-voltage cable, which differ by direct-buried, conduit, and open-tray conditions. Q: Why does the installation method change the size? A: Heat dissipation depends on the surroundings. A directly buried cable in soil cools differently than one in an underground duct or open tray, so each method has its own ampacity. Conduit installations generally carry the least current for a given size, which is why the method selector matters. Q: How is voltage drop calculated? A: For a three-phase circuit the drop is the square root of 3 times the current times the run length times the cable impedance, using the per-1000-foot resistance and reactance with the load power factor. The result is shown in volts and as a percentage of the line-to-line voltage, with a 3% target. Q: Do I still need to apply correction factors? A: Yes. The listed ampacities are single-circuit baseline values. You must apply corrections for ambient earth or air temperature, grouping of multiple circuits, burial depth, and soil thermal resistivity. In hot or congested installations the corrected ampacity can be significantly lower, requiring a larger conductor. Q: Does this replace an engineered cable study? A: No. Medium-voltage systems require attention to short-circuit withstand, shield grounding and sizing, terminations, and coordination that this tool does not address. Use it for preliminary sizing and verify the final design against IEEE Std 835, the NEC, and the cable manufacturer's published ampacity tables. #### Solar + Battery Hybrid System Sizing Calculator URL: https://geratools.com/solar-battery-hybrid-calculator Balance daily solar generation against a day and night load split, size the battery bank to hit a target self-sufficiency ratio at a given depth of discharge, and size the hybrid inverter from peak load. Built for AC-coupled and DC-coupled hybrid backup design. How to use: 1. Enter your load profile: Provide daily energy use in kWh and the share of that load consumed at night or when the sun is not shining. 2. Set site and target parameters: Enter peak sun hours, system losses, your target self-sufficiency percentage and the usable battery depth of discharge. 3. Read the three sizes: The tool returns the solar array size in kW, the battery capacity in kWh and Ah, and the continuous hybrid inverter rating. FAQ: Q: How is the solar array sized? A: The array must generate the target self-sufficient share of daily load after losses. Array kW equals daily load times the self-sufficiency fraction, divided by peak sun hours times the derate factor (one minus losses). Q: How is the battery sized? A: The battery covers the night and no-sun portion of the load. Capacity in kWh equals daily load times the night fraction times the self-sufficiency target, divided by the usable depth of discharge, then converted to amp-hours at the bus voltage. Q: What are peak sun hours? A: Peak sun hours are the equivalent number of hours per day at full 1000 W per square metre irradiance. A site averaging 4.5 peak sun hours receives the same daily energy as 4.5 hours of full midday sun, even though actual daylight is longer. Q: How big should the hybrid inverter be? A: The inverter must serve the peak AC load and pass through solar power to loads and charging at once. The tool sizes it to the larger of the peak load or array power with a 1.25 surge headroom factor to cover motor starting and brief overloads. Q: What self-sufficiency target is realistic? A: Targeting 100 percent off-grid autonomy requires large oversizing for cloudy days and seasonal swings. Many grid-tied hybrid systems aim for 70 to 90 percent self-sufficiency and let the grid cover the rest, which is far cheaper per kWh. #### Transformer Efficiency & No-Load Loss Calculator URL: https://geratools.com/transformer-no-load-loss-calculator Uses transformer nameplate no-load (core) loss and full-load (copper) loss to compute efficiency at any percent loading via the standard efficiency equation, and totals the annual kWh wasted as constant no-load loss. For engineers selecting efficient transformers. How to use: 1. Enter the nameplate ratings: Type the transformer kVA rating and its no-load (core) loss and full-load (copper) loss in watts from the test report or nameplate. 2. Set the operating point: Enter the percent of rated load the transformer typically carries and the load power factor to evaluate efficiency at that condition. 3. Read efficiency and annual loss: The tool returns total losses and efficiency at that load plus the constant annual kWh wasted as no-load loss, which runs whenever the transformer is energized. FAQ: Q: What is the efficiency formula used? A: Efficiency is output power divided by input power: η = (S × loadFraction × PF) / (S × loadFraction × PF + W0 + loadFraction² × Wk). W0 is the constant no-load core loss and Wk is the full-load copper loss, which scales with the square of the load fraction. Q: Why does copper loss scale with load squared? A: Copper (load) loss is I²R heating in the windings. Current is proportional to load, so the loss rises with the square of the load fraction. At half load the copper loss is only a quarter of its full-load value, while core loss stays constant. Q: What is no-load loss and when does it occur? A: No-load or core loss is the energy lost magnetizing the iron core. It is essentially constant whenever the transformer is energized, even with no load connected, so it runs 8,760 hours a year and dominates the losses on lightly loaded transformers. Q: At what load is a transformer most efficient? A: Peak efficiency occurs where copper loss equals core loss, which happens at a load fraction equal to the square root of W0 divided by Wk. Most distribution transformers are designed to peak near 35 to 50 percent load, matching typical duty. Q: How do I estimate annual no-load energy? A: Multiply the no-load loss in watts by 8,760 hours and divide by 1,000 to get kWh per year. A 100-watt core loss costs 876 kWh a year regardless of load, which is why low-no-load designs under DOE and TP-1 standards save money on lightly loaded units. #### Resistor Color Code Calculator URL: https://geratools.com/resistor-color-code-calculator Free resistor color code calculator. Convert colour bands to resistance (4, 5 or 6-band) and back again, with tolerance, temperature coefficient and a live visual of the painted bands. 100% in your browser. How to use: 1. Choose a direction: Switch between Colours to resistance (decode a real resistor) and Resistance to colours (find the bands for a target value). 2. Pick the band count: Select 4, 5 or 6 bands. 5 and 6-band resistors carry a third significant-figure band; 6-band adds a temperature coefficient. 3. Set the colours or the value: In decode mode pick each band colour; in encode mode type a resistance, choose the unit and a tolerance. The result and the painted resistor update live. FAQ: Q: How do I read a 4-band resistor? A: The first two bands are significant digits, the third is the multiplier (a power of ten) and the fourth is the tolerance. For example brown-black-red-gold is 1, 0, times 100 = 1 kΩ at ±5%. Q: What is different about a 5-band resistor? A: A 5-band resistor uses three significant-figure bands instead of two, then a multiplier and a tolerance band. The extra digit gives a more precise value, which is why precision (E96, 1% and tighter) parts use five bands. Q: What does the sixth band mean? A: On a 6-band resistor the final band is the temperature coefficient (TCR) in ppm/°C — how much the resistance drifts per degree. Brown is 100 ppm/°C, red 50, and so on down to 1 ppm/°C for high-stability parts. Q: How are gold and silver bands handled? A: As multipliers gold means ×0.1 and silver means ×0.01, which is how sub-10 Ω values are encoded. As tolerance bands gold means ±5% and silver means ±10%. The calculator applies whichever role the band is in. Q: Why does the value-to-colours mode say "nearest encodable value"? A: Colour bands can only represent values rounded to 2 (4-band) or 3 (5/6-band) significant figures times a power of ten. If your input has more precision than that, the tool rounds to the closest band-representable value and tells you what it used. Q: Does this work for surface-mount (SMD) resistors? A: No. SMD chip resistors are not colour-banded — they use printed numeric codes (such as the 3-digit, 4-digit or EIA-96 systems). This calculator covers axial through-hole resistors with painted colour bands. #### Capacitor Code Calculator URL: https://geratools.com/capacitor-code-calculator Decode any 3-digit ceramic or film capacitor code (e.g. 104) into pF, nF and µF, or encode a capacitance back into its EIA code. Includes tolerance letter (IEC 60062) and voltage rating. 100% browser-side, nothing uploaded. How to use: 1. Choose a direction: Select "Code to Capacitance" to decode a printed marking, or "Capacitance to Code" to find the EIA code for a known value. 2. Enter the 3-digit code or capacitance: In decode mode type the three digits printed on the body (e.g. 104). In encode mode type the value and pick pF, nF or µF from the unit selector. 3. Select tolerance and voltage: Choose the tolerance letter (J = ±5%, K = ±10%, M = ±20% are most common) and the EIA-198 voltage code if marked on the part. 4. Read the result and copy: The result shows capacitance in all three units, the tolerance range in absolute values, and the rated voltage. Hit Copy result to paste into a BOM or notes. FAQ: Q: How do I read a 3-digit capacitor code? A: The first two digits are the significant figures and the third is the power-of-ten exponent. The result is in picofarads. So 104 means 10 x 10^4 = 100,000 pF = 100 nF = 0.1 µF. The special cases are exponent 8 (x0.01) and exponent 9 (x0.1) for sub-picofarad values. Q: What is the value of a 104 capacitor? A: 104 decodes to 10 x 10^4 = 100,000 pF = 100 nF = 0.1 µF. This is one of the most common decoupling values, used across virtually every digital circuit to filter power-supply noise at the IC power pins. Q: What do the tolerance letters B, C, D, F, G, J, K, M mean? A: B = ±0.1 pF, C = ±0.25 pF, D = ±0.5 pF (all absolute, for small values). F = ±1%, G = ±2%, J = ±5%, K = ±10%, M = ±20%, N = ±30% (all percentage). J, K and M are by far the most common on general-purpose ceramics. Precision film capacitors use F or G. Q: What does the voltage code letter mean? A: After the 3-digit body code and tolerance letter, some parts add an EIA-198 voltage rating letter. L means 100 V, H means 50 V, J means 63 V, and so on. Not all manufacturers use this suffix — check the datasheet if absent. Q: Can I go backwards from capacitance to code? A: Yes. Switch to "Capacitance to Code" mode, type the value and choose pF, nF or µF. The tool finds the 3-digit EIA code that exactly represents that value. Only values that land on an EIA significant-figure step (10–99 significant digits) have valid codes; intermediate values will show an error. Q: Why does my code start with 0, like 010? A: Single-significant-digit values below 10 pF are sometimes encoded with a leading zero. 010 means 1 x 10^0 = 1 pF. Codes starting with 00x are rare and usually represent sub-picofarad values that require exponent 8 or 9. Q: Is this calculator accurate for SMD capacitors? A: Yes. Surface-mount ceramics use exactly the same 3-digit EIA coding system as through-hole parts. The only difference is that very small 0201 and 0402 packages sometimes use a 2-character code — that system is not covered here; use the 3-digit decoder for any part where you see three numeric digits. #### 555 Timer Calculator URL: https://geratools.com/555-timer-calculator Free 555 timer calculator. Compute astable oscillator frequency, period, duty cycle, T_high and T_low from R1, R2 and C — or solve in reverse for the resistor values that hit a target frequency. Monostable mode calculates pulse width T = ln(3)×R×C. Full step-by-step working shown. Runs entirely in your browser. How to use: 1. Choose astable or monostable mode: Astable mode generates a continuous square wave — use it for oscillators, blinkers and tone generators. Monostable mode fires a single timed pulse each time the trigger pin is pulled low. 2. Enter your component values: Type resistor values with unit suffixes such as 10k, 4.7k or 1M. Enter capacitor values as 100nF, 10µF or 47pF. The calculator accepts all common SI prefixes so there is no need to convert to base units. 3. Read the timing results: For astable mode the calculator shows frequency, period, T_high, T_low and duty cycle. For monostable mode it shows the output pulse width. All values are displayed with auto-scaled units: ns, µs, ms, s or Hz, kHz, MHz. 4. Use solve-for to find R1 and R2: Switch to "Find R1 and R2" in astable mode, enter your target frequency, desired duty cycle (must exceed 50%) and the capacitor you have on hand. The tool computes the exact resistor values; pick the nearest E12 or E24 standard parts and verify the result with the forward-calculate mode. 5. Load a preset circuit: Expand the "Common circuit presets" panel and click any row to pre-fill the inputs with values for a well-known application such as a 1 Hz LED blinker, a 1 kHz buzzer tone or a 38 kHz IR carrier frequency. FAQ: Q: What is the 555 timer astable frequency formula? A: The standard formula is f = 1.44 / ((R1 + 2×R2) × C), where R1 and R2 are in ohms and C is in farads. This comes from the two half-period expressions T_high = ln(2)×(R1+R2)×C and T_low = ln(2)×R2×C. The constant 1.44 is the rounded form of 1 / ln(2) = 1.4427. Q: Why is the duty cycle always above 50% in standard astable mode? A: In the standard circuit the capacitor charges through both R1 and R2 (HIGH time) but discharges only through R2 (LOW time). Because T_high always includes R1, it is always longer than T_low, making the duty cycle always above 50%. To achieve a 50% or lower duty cycle you must add a bypass diode in parallel with R2 so the cap charges only through R1, or use a CMOS 555 variant with a symmetrical network. Q: What is the 555 monostable pulse width formula? A: The exact formula is T = ln(3) × R × C, where ln(3) ≈ 1.0986. Many datasheets approximate this as T ≈ 1.1 × R × C; the difference is less than 0.1% and well within component tolerance. The pulse ends when the capacitor charges to 2/3 of the supply voltage V_cc, at which point the internal upper comparator resets the flip-flop and discharges the cap. Q: What values of R1, R2 and C should I choose? A: Keep R1 above about 1 kΩ to limit discharge current through the internal output transistor. R2 can be as low as a few hundred ohms for high-frequency operation or as high as several megaohms for long timing intervals. Typical capacitor values range from a few picofarads (high frequency) to tens of microfarads (long delays). Electrolytic capacitors above about 10 µF introduce significant leakage at slow charge rates, so use film or tantalum types for precision timing. Q: What supply voltage does a 555 timer need? A: The bipolar NE555 operates from 5 V to 15 V and sources/sinks up to 200 mA output current. The CMOS TLC555 or LMC555 runs from 2 V to 15 V, draws far less supply current and is better suited to battery-powered designs. Supply voltage does not affect the timing — the internal comparators trip at exactly 1/3 and 2/3 of V_cc, so the charge/discharge curves scale proportionally. Q: How accurate is a 555 timer circuit in practice? A: The timing accuracy is limited mainly by component tolerances. A 5% resistor and a 10% capacitor can shift the frequency by ±15%. Temperature drift of the capacitor (especially electrolytic types) adds further variation. For precision timing use 1% metal-film resistors and NP0/C0G or film capacitors. The 555 internal threshold is nominally 2/3 V_cc but has ±1% typical variation across devices, adding a few percent more error. #### LC Resonant Frequency Calculator URL: https://geratools.com/lc-resonant-frequency-calculator Free LC resonant frequency calculator. Solve for f, L, or C using the exact formula f=1/(2pi*sqrt(LC)). Shows angular frequency, reactance, characteristic impedance, Q factor, and full step-by-step working. Runs entirely in your browser. How to use: 1. Choose what to solve for: Select whether you want to find the resonant frequency, the required inductance, or the required capacitance. The selected field becomes the output and is greyed out. 2. Enter the known component values: Type the inductance and capacitance (or frequency and one component) in the input boxes. Use the unit dropdowns to switch between H/mH/µH/nH and F/µF/nF/pF as needed. 3. Add series resistance for Q factor (optional): Fill in the series resistance R to get the Q factor and bandwidth of the circuit. Leave it at zero to skip this. 4. Read the results and show working: The calculator instantly displays the resonant frequency, angular frequency, period, reactance at resonance, characteristic impedance, and optional Q factor. Click "Show working" to see every arithmetic step. FAQ: Q: What is the formula for LC resonant frequency? A: The standard formula is f = 1 / (2π × √(L × C)), where f is the resonant frequency in hertz, L is inductance in henries, and C is capacitance in farads. It is derived by equating inductive reactance XL = 2πfL with capacitive reactance XC = 1/(2πfC) and solving for f. Q: Why does an LC circuit resonate at one specific frequency? A: At resonance, the inductive reactance and capacitive reactance are equal and opposite. Energy oscillates back and forth between the magnetic field of the inductor and the electric field of the capacitor. Below the resonant frequency the circuit is capacitive; above it the circuit is inductive. Only at f₀ do they cancel exactly. Q: How do I find inductance if I know the frequency and capacitance? A: Rearrange the formula to L = 1 / ((2πf)² × C). Select "Inductance" from the solve-for buttons, enter f and C, and the calculator shows the result together with every arithmetic step. Q: What is the Q factor and why does it matter? A: Q (quality factor) measures how sharp or selective the resonance is. For a series RLC circuit it is Q = (1/R) × √(L/C). A high Q means a narrow bandwidth and a tall, sharp resonance peak — ideal for radio tuning and bandpass filters. A low Q gives a broad, flat response suited to wideband circuits. Q: What is characteristic impedance Z₀ in an LC circuit? A: Z₀ = √(L/C) is the impedance each reactance presents at resonance (since XL = XC = Z₀ at f₀). It tells you the voltage magnification: in a series resonant circuit the voltage across L or C alone equals Q × V_source, where V_source is the supply voltage. Q: Does component tolerance affect the resonant frequency much? A: Yes — significantly. Because f ∝ 1/√(LC), a 1 % change in either L or C shifts the frequency by about 0.5 %. Real capacitors can drift ±5–20 % with temperature and age; inductors vary with core material and winding. For precision work (crystal filters, RF tuners) trimmer capacitors or adjustable inductors compensate for tolerance. #### Op-Amp Gain Calculator URL: https://geratools.com/op-amp-gain-calculator Free op-amp gain calculator covering non-inverting, inverting, voltage follower, difference amplifier and transimpedance configurations. Computes Av, dB gain, GBW-limited bandwidth, slew-rate bandwidth and solves for Rg. Runs entirely in your browser. How to use: 1. Choose your amplifier configuration: Select non-inverting, inverting, voltage follower, difference, or transimpedance from the dropdown. The correct formula is displayed immediately. 2. Enter your resistor values: Type Rf and Rg using SI prefixes: k for kilohms, M for megohms (e.g. 100k, 10k). For transimpedance, enter the input current instead of Rg. 3. Check gain and bandwidth: Read voltage gain in V/V and dB, then expand Bandwidth Settings to enter your op-amp datasheet GBW product and slew rate for a complete bandwidth budget. 4. Solve for Rg: Click Solve for Rg, enter your desired gain, and the calculator returns the exact Rg needed — plus a note to pick the nearest E24/E96 standard value. FAQ: Q: What is the gain formula for a non-inverting op-amp? A: The closed-loop voltage gain is Av = 1 + Rf / Rg. Because the signal enters the non-inverting (+) input, the output is in phase with the input. The minimum gain is 1 (unity), reached when Rf = 0 or Rg → ∞, which gives the voltage-follower configuration. Q: How does an inverting amplifier differ? A: The input signal is applied through Rg to the inverting (−) input, and feedback is taken from output to the same node. The gain is Av = −Rf / Rg. The negative sign means the output is 180° out of phase with the input. Input impedance equals Rg, which is important when driving the amplifier from a source with output impedance. Q: What is the GBW product and why does it matter? A: Gain–Bandwidth Product (GBW or GBWP) is a constant for a given op-amp: GBW = |Av| × f−3dB. If you double the gain, the usable bandwidth halves. For example, an op-amp with GBW = 1 MHz set to a gain of 10 has a −3 dB bandwidth of only 100 kHz. Always check that your signal frequency is well below this limit. Q: What limits an op-amp when GBW seems fine? A: Slew rate. Even if the small-signal bandwidth is adequate, the op-amp output can only swing at a maximum rate of SR volts per microsecond. For a large-amplitude sinusoid at frequency f with peak voltage Vpeak, the required slew rate is 2π × f × Vpeak. Exceeding this causes slew-rate distortion regardless of gain. The calculator shows both limits and takes the more restrictive one as effective bandwidth. Q: What is a transimpedance amplifier used for? A: A transimpedance amplifier (TIA) converts a current input (from a photodiode, sensor, or DAC output) to a voltage output. The gain is expressed in ohms: Vout = −Iin × Rf. The inverting input sits at virtual ground (0 V), so the current flows entirely through Rf. TIAs are ubiquitous in optical receivers, medical instrumentation, and high-precision current sensing. Q: How do I choose standard resistor values for my target gain? A: Use the Solve for Rg feature: enter your desired gain and Rf, and the calculator returns the exact Rg. Because ideal values rarely land on a standard resistor, round to the nearest E24 (5%) or E96 (1%) series value and verify the resulting gain deviation is within your tolerance. For precision applications, use 0.1% thin-film resistors on both Rf and Rg to minimise gain error and common-mode rejection ratio (CMRR) degradation. #### PC Power Supply Calculator URL: https://geratools.com/pc-power-supply-calculator Free PC power supply calculator. Enter your CPU TDP, GPU TBP, RAM, drives and fans; get the minimum recommended PSU wattage with headroom, 80 PLUS efficiency correction and a full component breakdown. 100% client-side — no data sent to any server. How to use: 1. Select your CPU: Choose a preset (e.g. mid-range Core i5 / Ryzen 5 at 95 W) or pick "Custom" and type the exact TDP from your CPU's spec sheet. 2. Select your GPU: Pick the closest GPU tier or choose "Custom" and enter the Total Board Power (TBP) figure from the manufacturer's specifications page. 3. Fill in the rest of your build: Enter the number of RAM sticks, HDDs, SSDs, case fans and any miscellaneous wattage for USB devices, RGB lighting or an AIO pump. 4. Choose your 80 PLUS tier: Select the efficiency certification of the PSU you are considering. Gold (90%) is the most cost-effective sweet spot for most builds. 5. Set your headroom buffer: Drag the slider to 20-30% for a balanced build, 40-50% if you plan to upgrade components or run the PC at sustained peak load. 6. Read your recommended wattage: The calculator shows the minimum standard PSU tier that covers your system TDP with headroom and efficiency correction, plus a startup peak estimate. FAQ: Q: How is the recommended PSU wattage calculated? A: The calculator sums the TDP of every component (CPU + GPU + RAM + drives + fans + misc) to get the System DC TDP. It then multiplies by (1 + headroom%) to give the required DC wattage. Because a PSU wastes some power as heat, the required AC wall-draw is DC_required ÷ efficiency — for an 80 PLUS Gold PSU at 90% that means drawing 11% more from the wall than the components actually consume. Finally the figure is rounded up to the nearest standard PSU tier (450 W, 500 W, 550 W … 1600 W). The formula is: PSU_rating = nextTier(systemTdp × (1 + headroom) ÷ efficiency). Q: What is TDP and why does it matter for PSU sizing? A: TDP (Thermal Design Power) is the maximum sustained power draw a component is designed for under full load. Intel and AMD publish TDP figures for CPUs; GPU makers publish TBP (Total Board Power). Adding up all TDP figures gives the worst-case DC load the PSU must supply. Exceeding a PSU's rated wattage — even briefly — causes the unit to shut down or, in extreme cases, fail permanently. Q: What is 80 PLUS certification and why does it affect PSU sizing? A: 80 PLUS is an independent certification that guarantees a PSU converts AC mains power to DC at 80% or higher efficiency at 20%, 50% and 100% load. Higher tiers (Bronze, Silver, Gold, Platinum, Titanium) achieve 85–94%. Because lost power becomes heat, a less efficient PSU must be rated higher to deliver the same DC wattage to your components. A 500 W White PSU (80% efficiency) draws 625 W from the wall at full load; a 500 W Gold PSU (90%) draws only 556 W — the Gold costs less to run and runs cooler. Q: How much headroom should I leave in my PSU? A: Most builders aim for 20–30% headroom. At that margin the PSU operates at 40–70% of its rated capacity, which is the efficiency sweet spot for most 80 PLUS designs. Below 10% headroom the PSU runs near its limits — components brown out on transient spikes. Above 50% headroom you are paying for capacity you will never use and the PSU spends most of its time at very low load where efficiency also drops. Choose 40–50% only if you plan hardware upgrades or run sustained workstation-class loads. Q: Why does the calculator show a startup peak wattage? A: When motors spin up (fans, HDDs) and capacitors charge at boot, components draw a brief current spike — sometimes 5–15% above steady-state TDP. The calculator multiplies system TDP by a tier-specific peak multiplier (1.03 for Titanium, 1.10 for White/Bronze) to give an estimated peak. Your PSU must handle this without triggering its over-current protection. The recommended wattage already accounts for this, but the figure is shown so you can cross-check premium PSUs that publish separate peak and continuous ratings. Q: Does the calculator account for future upgrades? A: Not automatically — it calculates the wattage for the components you enter. If you plan to add a second GPU, NVMe drives, or upgrade to a higher-TDP CPU, increase the headroom slider to 40–50% or simply enter the upgraded component TDPs directly. Buying a PSU with 30–40% more capacity than your current build is a common strategy for extending the PSU's useful life across two or three hardware generations. Q: Is a modular or semi-modular PSU better? A: Modularity describes cable management, not electrical performance — it has no effect on the wattage calculation. Fully modular PSUs let you attach only the cables you use, reducing clutter and improving airflow inside the case. Semi-modular PSUs have fixed cables for the ATX 24-pin and CPU connectors but modular PCIe and SATA connectors. For most builds a semi-modular Gold or better PSU at the recommended wattage is the optimal value choice. #### Capacitor Charge Calculator URL: https://geratools.com/capacitor-charge-calculator Free capacitor charge calculator. Instantly compute Q = CV, energy E = ½CV², and the voltage across a capacitor at any point during charging or discharging using the exact RC exponential formula. 100% browser-side — no data sent anywhere. How to use: 1. Choose a calculation mode: Select "Static charge / energy" to find Q, V or C at steady state, or "Charge / discharge over time" to model a real RC transient. 2. Enter your known values: Type capacitance, voltage or charge — the unknown is solved automatically. Use the unit dropdowns (pF to F, mV to kV, etc.) to avoid manual conversion. 3. Read the results table: The solved variable is highlighted. Energy stored (E = ½CV²) is always shown alongside. The capacitor diagram fills proportionally to the charge level. 4. Use the dynamic tab for time-dependent questions: Enter R, C, V₀ and elapsed time t. The calculator returns Vc(t), Q(t), energy at t, percentage charged, and the time needed to reach any target voltage level. 5. Copy the working: Click "Copy results" to get a plain-text summary of the formula, substituted values and answer — useful for lab reports or design notes. FAQ: Q: What is the formula for charge stored in a capacitor? A: The fundamental relationship is Q = C × V, where Q is the charge in coulombs, C is the capacitance in farads, and V is the voltage across the plates in volts. Rearranged: V = Q/C to find voltage, or C = Q/V to find capacitance. This tool solves all three forms. Q: How is the energy stored in a capacitor calculated? A: Energy E = ½ × C × V². For example, a 100 µF capacitor charged to 12 V stores E = 0.5 × 100 × 10⁻⁶ × 144 = 7.2 mJ. The square of voltage means doubling the voltage quadruples the stored energy, while doubling capacitance only doubles it. Q: What is the capacitor charging formula and where does e^(−t/RC) come from? A: When a capacitor charges through a resistor the voltage follows Vc(t) = V₀ × (1 − e^(−t/RC)). This exponential form comes from solving the first-order differential equation i = C dV/dt with i = (V₀ − Vc)/R — the current falls as the capacitor fills, giving a decaying exponential. RC (= τ, the time constant) sets the speed: after one τ the capacitor reaches 63.2% of V₀; after 5τ it is considered fully charged at 99.3%. Q: How long does it take a capacitor to fully charge? A: Theoretically a capacitor never reaches exactly 100% because the exponential approaches V₀ asymptotically. In practice, engineers treat five time constants (5τ = 5RC) as "fully charged" — at that point the capacitor is at 99.33% of the supply voltage. Use the dynamic tab to calculate the exact time to any target percentage. Q: What is the discharge formula for a capacitor? A: During discharge through a resistor with no external source, Vc(t) = V₀ × e^(−t/RC). The voltage decays from V₀ toward zero. After 1τ the voltage has fallen to 36.8% of V₀; after 5τ it is below 0.7% — effectively fully discharged. The calculator shows both curves in the "Charge / discharge over time" tab. Q: Can I use this calculator for capacitors in filters, timers or power supplies? A: Yes. RC filters, 555 timer networks, camera flash circuits, power-supply smoothing capacitors and motor start/run capacitors all follow the same Q = CV and exponential transient equations this tool uses. Enter your component values and supply voltage to verify charge levels, energy budgets and timing at any point in the cycle. #### Dipole Antenna Calculator URL: https://geratools.com/dipole-antenna-calculator Free dipole antenna calculator: enter frequency and get the correct element length for a half-wave dipole, quarter-wave monopole, or full-wave loop. Supports metres, feet, inches, velocity-factor correction, and solve-for-frequency mode. Runs entirely in your browser. How to use: 1. Choose your antenna type: Select half-wave dipole, quarter-wave monopole, or full-wave loop. The half-wave dipole is the most common starting point for HF and VHF antennas. 2. Enter the operating frequency: Type the desired centre frequency in Hz, kHz, MHz, or GHz. Use the quick preset buttons to jump directly to popular amateur radio bands or ISM frequencies. 3. Adjust the velocity factor: For bare copper wire in open air use 0.95 (the default). For insulated wire or a specific feedline type, enter the manufacturer velocity factor — typically 0.66–0.82 for coax. 4. Read off the element length: The total length and (for the dipole) each arm length appear immediately in your chosen output unit. Hit "Show working" to see every arithmetic step. 5. Reverse-solve from a known length: Switch "Solve for" to Frequency, enter the physical length you have on hand, and the calculator returns the resonant frequency. FAQ: Q: What is the standard formula for a half-wave dipole? A: The theoretically exact length is L = 0.5 × c / f, where c = 299,792,458 m/s. In practice a short-end correction factor (velocity factor ≈ 0.95 for wire in air) is applied, giving L = 0.95 × c / (2f). That simplifies to the classic radio shorthand: length in metres = 142.5 / f(MHz), or length in feet = 468 / f(MHz). Q: Where does the "468" constant come from? A: 492.126 feet is the theoretical half-wavelength at 1 MHz (= 300 m / 2 converted to feet). Multiplying by 0.95 (the standard velocity factor for wire antennas) gives 467.5 ≈ 468. The constant "492" is sometimes used for the theoretical case and "468" for the practical case. Q: What is velocity factor and why does it matter? A: Electromagnetic waves travel slightly slower along a conductor than in free space. The velocity factor (VF) is that ratio — typically 0.95 for bare wire, 0.66–0.82 for coaxial cable, and 0.82–0.95 for ladder line. If you build an antenna that is physically too long you will be resonant below your target frequency; too short and you will be above it. Entering the correct VF gives you the precise cut length from the start. Q: What feed impedance should I expect at the centre of a half-wave dipole? A: In free space (antenna in the clear, far from ground and structures) the radiation resistance of a resonant half-wave dipole is approximately 73 Ω. In practice, height above ground, nearby objects, and element diameter all perturb this figure — measurements near ground can see values anywhere from 30 Ω to over 100 Ω. Many builders feed with 50 Ω coax through a 1:1 balun and trim for minimum SWR. Q: How is a quarter-wave monopole different from a half-wave dipole? A: A monopole is half a dipole erected vertically over a conductive ground plane (radials, vehicle roof, ground-mounted radials). The ground plane acts as a mirror image of the missing lower half. Its feed impedance is half that of the equivalent dipole — approximately 36.5 Ω — and its directivity is 5.19 dBi because radiation is confined to the upper hemisphere. A quarter-wave vertical over four or more quarter-wave radials approximates a perfect ground plane and is the textbook antenna for VHF/UHF mobile and land-mobile work. Q: Can I use this for Wi-Fi or 2.4 GHz antennas? A: Yes. Selecting 2.4 GHz and half-wave dipole gives a total element length of about 59 mm (each arm ≈ 29.5 mm). This is exactly the dimension used in printed PCB dipoles and duck antennas for Wi-Fi equipment. The same approach works for 5.8 GHz (≈ 24 mm total) and 433 MHz / 868 MHz IoT antennas. #### Three-Phase Power Calculator URL: https://geratools.com/three-phase-power-calculator Free three-phase power calculator. Compute real power (kW), apparent power (kVA), reactive power (kVAR), line current, line voltage, phase angle and power factor for balanced wye or delta loads. Full step-by-step working shown. Runs entirely in your browser — no data is sent to a server. How to use: 1. Choose what to solve for: Pick "Power (S, P, Q)" to find apparent, real and reactive power from voltage and current; "Current (I_L)" to find line current from voltage and real power; or "Voltage (V_LL)" to find the required line voltage. 2. Select your load configuration: Choose Wye (star) or Delta — the calculator derives phase quantities for both, so you can compare winding currents and voltages side by side. 3. Enter voltage and current (or power): Pick a standard line-to-line voltage from the preset list (208 V, 400 V, 415 V, 480 V, etc.) or type a custom value, then enter the line current in amps or the real power in watts depending on the solve direction. 4. Set the power factor: Choose a common preset (unity for purely resistive loads, 0.85–0.95 for typical motors and drives) or enter a custom value. The calculator converts pf to a phase angle and computes reactive power automatically. 5. Read the results and verify the power triangle: The results panel shows all six quantities plus the power triangle summary (kW / kVAR / kVA). Use "Show working" to follow the step-by-step arithmetic, then copy the full result set to your clipboard. FAQ: Q: What is the formula for three-phase power? A: For a balanced three-phase system the apparent power is S = √3 × V_LL × I_L (in VA). Real power is P = S × pf = √3 × V_LL × I_L × cos(θ). Reactive power is Q = S × sin(θ). Here V_LL is the line-to-line voltage, I_L is the line current, pf = cos(θ) is the power factor, and √3 ≈ 1.7321. Q: What is the difference between kW and kVA? A: kW (kilowatts) is real, or active, power — the energy per second that does useful work such as turning a shaft or producing heat. kVA (kilovolt-amperes) is apparent power — the product of RMS voltage and RMS current, which represents the total current the supply conductors must carry. The ratio kW ÷ kVA is the power factor. A motor drawing 10 kVA at pf 0.85 only delivers 8.5 kW of mechanical output; the remaining reactive component (kVAR) oscillates between source and load without doing net work but still heats cables and loads transformers. Q: Why does √3 appear in three-phase formulas? A: In a balanced three-phase system the three phase voltages are displaced by 120°. When you sum two phase voltages (which is what a line-to-line measurement spans) the magnitude of the resultant is √3 times the phase voltage magnitude. Hence V_LL = √3 × V_ph and S = 3 × V_ph × I_ph = √3 × V_LL × I_L. The √3 ≈ 1.7321 factor is exact: it is the square root of three. Q: What is the difference between wye (star) and delta? A: In a wye (Y) connection the three phase windings share a common neutral point. Phase voltage V_ph = V_LL ÷ √3 and phase current I_ph = I_L. In a delta (Δ) connection the windings form a triangle with no neutral. Phase voltage V_ph = V_LL (same as line voltage) but phase current I_ph = I_L ÷ √3. Both configurations produce the same total power for the same line quantities, but they affect insulation requirements and circulating current differently. Q: What power factor should I use for induction motors? A: A large, fully loaded three-phase induction motor typically has pf 0.85–0.92. Smaller or lightly loaded motors may drop to 0.70–0.80. Variable frequency drives (VFDs) correct the power factor at the drive input to about 0.95–0.98. Purely resistive loads (heaters, incandescent lighting) have pf = 1.00. When in doubt use 0.85 as a conservative design estimate; the preset list covers the most common values. Q: How do I calculate three-phase current from kW? A: Rearrange the real-power formula: I_L = P ÷ (√3 × V_LL × pf). For example, a 15 kW (15,000 W) motor on a 400 V supply at pf 0.85 draws I_L = 15,000 ÷ (1.7321 × 400 × 0.85) = 15,000 ÷ 588.9 ≈ 25.5 A. The "Solve for Current" mode in this calculator performs exactly this rearrangement and shows the working. ### Automotive #### Australia Pension & Retirement Calculator URL: https://geratools.com/australia-pension-retirement-calculator Project your Australian Superannuation balance and retirement income. Models the Super Guarantee (SG 11.5%), voluntary contributions, investment growth and a sustainable drawdown, with a year-by-year projection. Runs in your browser. How to use: 1. Enter your age, salary and current super: Type your current age, planned retirement age, gross salary and existing Super balance so the tool knows how long it has to compound. 2. Set contributions and return: The Super Guarantee defaults to 11.5% of salary. Add any voluntary contributions and your expected annual investment return after fees. 3. Read your projected balance and income: See your projected Super balance at retirement and an estimate of the annual income it can sustainably provide over your retirement years. FAQ: Q: What is the Super Guarantee rate? A: The Super Guarantee (SG) is the minimum percentage of your salary your employer must pay into your Superannuation fund. It is 11.5% for the 2024–25 year and is legislated to rise to 12%. The tool defaults to 11.5% but you can change it to model future rates. Q: How is the projected Super balance calculated? A: Each year the tool adds your employer SG contribution plus any voluntary contributions to your balance, then grows the whole balance at your expected return after fees. Your salary grows each year too, so contributions rise over time. This compounds until your retirement age. Q: How is retirement income estimated? A: The tool spreads your projected balance, which keeps earning a return in retirement, across the years between retirement and your planned end age. It is an annuitised drawdown: a sustainable annual amount that draws the balance down to roughly zero over that period. Q: Does this include the Age Pension or tax? A: No. It models only your Superannuation. The government Age Pension, contributions tax, the transfer balance cap and earnings tax in pension phase are not included. Treat the result as your private Super projection, not your total retirement income. Q: What return should I assume? A: Returns vary by investment option. A balanced or growth Super option has historically returned mid-single-digit percentages after fees over the long run, but past performance is not a guarantee. Try a few values to see how sensitive your projection is to the return assumption. #### Automotive Gear Ratio & Speed Calculator URL: https://geratools.com/automotive-gear-ratio-speed Computes vehicle speed in mph or km/h at any engine RPM from the individual gear ratio, final drive ratio, and metric tire size. Builds a full RPM-versus-speed table for every gear, ideal for gear swaps, tire-size changes, and cruising RPM planning. How to use: 1. Enter engine RPM and tire size: Type the engine RPM you care about and your tire's section width, aspect ratio, and rim diameter to derive overall tire diameter. 2. Add the drivetrain ratios: Enter the final drive ratio and a comma-separated list of gear ratios from first gear through top gear. 3. Read the speed table: The tool shows the road speed in every gear at that RPM, in your chosen mph or km/h, so you can compare gearing or tire changes. FAQ: Q: What formula converts RPM to road speed? A: Wheel RPM equals engine RPM divided by the product of the gear ratio and final drive ratio. Multiplying wheel RPM by the tire circumference and converting units gives road speed. The tool uses 63360 inches per mile and pi times tire diameter for circumference. Q: How is tire diameter calculated from a size like 225/45R17? A: Sidewall height in millimetres is section width times aspect ratio divided by 100. Overall diameter in inches is the rim diameter plus two sidewalls converted from millimetres at 25.4 mm per inch. So 225/45R17 is about 24.97 inches tall. Q: Why is my real speed slightly lower than the tool shows? A: The calculation assumes no tire slip and uses the unloaded tire diameter. Under load the tire deflects and the rolling diameter shrinks slightly, and there is minor driveline slip, so actual speed is typically one to two percent below the calculated figure. Q: How does changing the final drive ratio affect speed? A: A higher numerical final drive (say 4.10 instead of 3.73) multiplies torque but lowers speed per RPM and raises cruising RPM. A lower numerical ratio does the opposite, giving taller gearing, lower highway RPM, and better fuel economy at the cost of acceleration. Q: Can I use this to check cruising RPM for a tire upgrade? A: Yes. Enter your top gear and final drive, set the RPM to your typical cruise figure, then compare the speed with your old and new tire sizes. A taller tire raises speed per RPM, which lowers the RPM needed for a given highway speed. #### Boiler Horsepower & Steam Output Calculator URL: https://geratools.com/boiler-horsepower-calculator Convert boiler horsepower to BTU/hr, kW, and pounds of steam per hour, and back from a kW output. Applies an efficiency factor to find required fuel input for sizing steam boilers and checking nameplate data. Runs in your browser. How to use: 1. Choose your input: Select whether you know the boiler horsepower rating or the thermal output in kilowatts. 2. Enter the value and efficiency: Type the rating and the boiler's combustion or thermal efficiency as a percentage so fuel input can be derived. 3. Read the conversions: The tool shows BTU/hr, kW, pounds of steam per hour, and the required fuel input for your efficiency. FAQ: Q: What exactly is one boiler horsepower? A: One boiler horsepower is the energy needed to evaporate 34.5 pounds of water per hour at 212 °F into dry saturated steam at atmospheric pressure. That equals 33,475 BTU per hour, or about 9.81 kW of gross thermal output. Q: Why does boiler horsepower differ from mechanical horsepower? A: Mechanical horsepower (746 W) measures shaft work, while boiler horsepower measures heat output and is roughly 13 times larger at 9.81 kW. The two share a name for historical reasons but are not interchangeable units. Q: What does the efficiency input do? A: Gross output is the heat delivered to the steam. Fuel input is always larger because combustion is not perfect. The tool divides output by your efficiency to estimate the fuel input rate, for example 82 percent efficiency raises a 100 BHP output to roughly 4.08 million BTU/hr of fuel. Q: What does from-and-at 212 °F mean? A: It is a standard reference condition: feedwater already at 212 °F being turned to steam at 212 °F. Real boilers with cooler feedwater and higher pressures produce somewhat less steam per BHP, so treat the steam figure as a nominal rating. Q: Can I size a boiler with this tool? A: Use it to translate between rating units and to estimate fuel demand, but final sizing must account for actual feedwater temperature, operating pressure, blowdown, and load diversity. Treat the result as a first-pass nameplate check. #### Car Commute Carbon Calculator URL: https://geratools.com/car-commute-carbon Input one-way distance, days per week, fuel type (petrol, diesel, hybrid, EV), and vehicle size to compute annual commute CO2e using UK DEFRA emission factors. Compares with bus, train, cycling, and walking. Useful for employees and sustainability teams. How to use: 1. Enter your commute: Type the one-way distance and how many days a week you travel to work. 2. Pick your vehicle: Choose fuel type and vehicle size; the tool uses the matching DEFRA per-kilometre emission factor. 3. Compare modes: Read your annual car CO2e and a side-by-side comparison with bus, rail, cycling, and walking for the same journey. FAQ: Q: How is annual commute CO2 calculated? A: The tool multiplies your round-trip distance by the per-kilometre emission factor for your vehicle, then by the number of commuting days per year (days per week times the working weeks you set). The result is annual CO2e in kilograms. Q: Why does an electric car still show some emissions? A: An EV produces no tailpipe CO2, but charging it draws electricity that usually carries some grid carbon. The tool applies a grid-based factor per kilometre, so the EV figure reflects how clean your electricity is. On a fully renewable tariff it approaches zero. Q: What emission factors does this use? A: It uses representative UK DEFRA average-car factors: around 0.17 kgCO2e per km for an average petrol car, 0.16 for diesel, 0.12 for a hybrid, and roughly 0.05 for an EV on the average grid. Larger vehicles scale these up. Q: How do bus and train compare? A: Public transport spreads emissions across many passengers, so per-passenger-kilometre figures are far lower: roughly 0.10 for a local bus and 0.035 for a national rail journey. Cycling and walking are effectively zero for the journey itself. Q: How many commuting days should I assume per year? A: A typical full-time pattern is about 46 working weeks after holidays. At five days a week that is 230 commuting days. The tool lets you set weeks and days so you can model hybrid working, for example three office days a week. #### Engineering Notation Converter URL: https://geratools.com/engineering-notation-converter Convert any number to engineering notation, where the exponent is always a multiple of three so the mantissa stays between 1 and 1000 and lines up with SI prefixes like k, M, m and µ. Runs entirely in your browser. How to use: 1. Enter your number: Type a value in plain decimal or scientific form, such as 47000 or 1.2e9. Negative and very small numbers are supported. 2. Read the engineering notation: The result shows the mantissa times a power of ten whose exponent is a multiple of three. 3. Match the SI prefix: Use the SI prefix line to translate the exponent into a familiar unit prefix such as kilo, mega, milli or micro. FAQ: Q: What is engineering notation? A: Engineering notation is a form of scientific notation where the power-of-ten exponent is always a multiple of three. This keeps the mantissa between 1 and just under 1000 and aligns directly with SI unit prefixes. Q: How does it differ from scientific notation? A: Scientific notation keeps the mantissa between 1 and 10 with any integer exponent. Engineering notation relaxes the mantissa to between 1 and 1000 so the exponent can stay a multiple of three. For example 47000 is 4.7 × 10⁴ scientifically but 47 × 10³ in engineering notation. Q: Why are multiples of three useful? A: SI unit prefixes step in factors of one thousand: kilo (10³), mega (10⁶), milli (10⁻³), micro (10⁻⁶), and so on. Forcing the exponent to a multiple of three lets you read the prefix straight off the result. Q: How is the engineering exponent chosen? A: The tool finds the ordinary base-10 exponent, then rounds it down to the nearest lower multiple of three. The mantissa is the original value divided by ten raised to that engineering exponent. Q: Does it handle very small numbers? A: Yes. A value like 0.0033 becomes 3.3 × 10⁻³, which corresponds to the milli prefix. The tool covers SI prefixes from yocto (10⁻²⁴) to yotta (10²⁴). #### EV vs Petrol Lifetime CO2 & Cost Comparator URL: https://geratools.com/ev-vs-petrol-lifetime-co2 Input vehicle segment, annual mileage, grid carbon intensity, fuel prices, and electricity tariff to model 10-year lifetime CO2e and total cost of ownership for an EV versus a petrol or diesel car, including battery-manufacturing carbon amortised over the vehicle life. How to use: 1. Enter mileage and lifetime: Set your annual distance and the number of years you will keep the car, which together set total lifetime distance. 2. Set energy and price inputs: Provide the EV's efficiency and your electricity tariff and grid intensity, plus the ICE car's fuel economy and fuel price. 3. Read CO2 and cost: The tool shows lifetime CO2e for each car, including amortised battery-manufacturing carbon, the emissions break-even distance, and 10-year running cost. FAQ: Q: Does an EV really have higher manufacturing emissions? A: Yes. Building an EV, mainly its battery, emits more CO2 up front than building a comparable petrol car, typically several tonnes more. The EV repays this 'carbon debt' through cleaner running, and this tool shows the distance at which it breaks even. Q: How is battery-manufacturing carbon estimated? A: It is approximated as the battery capacity in kWh times a manufacturing factor of around 70 kgCO2e per kWh of cell capacity. A 60 kWh battery therefore carries roughly 4.2 tonnes of extra embedded carbon, amortised across the vehicle's life in the comparison. Q: What grid intensity should I use for the EV? A: Use the grid where you charge. On a clean grid an EV's running emissions are tiny and it breaks even quickly; on a coal-heavy grid the running advantage shrinks and break-even takes far longer. The grid factor is the single biggest variable in the EV result. Q: Is the EV always cheaper to run? A: Usually, because electricity per mile costs less than petrol or diesel in most markets, especially on an off-peak tariff. But high electricity prices or very cheap fuel can narrow or reverse the gap, which is why the tool computes cost from your own figures. Q: What does the break-even distance mean? A: It is the lifetime distance at which the EV's lower running emissions have fully repaid its higher manufacturing emissions, so total CO2e becomes equal. Drive further than that and the EV is cleaner overall; drive less and the petrol car may have emitted less in total. #### G-Code Speed & Feedrate Calculator URL: https://geratools.com/gcode-speed-calculator Converts mm/s print speeds to the G-code feedrate F parameter in mm/min by multiplying by 60, and back the other way. Also computes the duration of a linear move from feedrate and distance for debugging and timing G-code. How to use: 1. Choose a conversion: Pick mm/s to feedrate to turn a slicer speed into the F value, or feedrate to mm/s to read an F value back into a familiar speed. 2. Enter the value: Type the print speed in mm/s (e.g. 60) or the feedrate in mm/min (e.g. 3600). The conversion is exact and instant. 3. Optionally time a move: Enter a move distance to also see how long that linear move takes at the given speed, useful for debugging and estimating segment durations. FAQ: Q: Why is G-code feedrate in mm/min, not mm/s? A: The F parameter in G-code (e.g. G1 X10 F3600) is defined in millimetres per minute by the RS-274 standard that CNC and 3D printer firmware follow. Slicers display speeds in mm/s for human readability, so a 60 mm/s setting becomes F3600 in the actual G-code. Q: What is the conversion formula? A: Feedrate (mm/min) = speed (mm/s) x 60, and speed (mm/s) = feedrate (mm/min) / 60. So 50 mm/s equals F3000, and F4800 equals 80 mm/s. The factor of 60 is simply seconds per minute. Q: How is move duration calculated? A: Duration = distance / speed. At a constant feedrate, a 30mm move at 60 mm/s takes 30 / 60 = 0.5 seconds. This ignores acceleration and jerk, so real moves are slightly slower on short segments, but it is accurate for steady-state long moves. Q: Does the F value persist across G-code lines? A: Yes. Once set, the feedrate stays in effect for subsequent G0/G1 moves until a new F value is given. That is why slicers emit an F only when the speed changes, not on every line. Keep that in mind when reading raw G-code. Q: Does this apply to travel moves too? A: Yes. Travel (non-printing) moves use the same F-in-mm/min convention, usually at a higher feedrate than printing moves. Convert travel speed the same way: 150 mm/s travel is F9000. #### Golf Green Speed (Stimpmeter) Calculator URL: https://geratools.com/golf-putting-green-speed-calculator Enter a Stimpmeter reading in feet to classify green speed from slow to tour-fast and get recommended stroke-weight adjustments for uphill and downhill putts on that surface. How to use: 1. Take the Stimpmeter reading: Roll balls down a Stimpmeter on a flat part of the green and average the roll-out distance in feet. 2. Enter the reading: Type the average distance in feet; the tool classifies the speed and shows where it sits on the slow-to-tour scale. 3. Apply the adjustments: Use the suggested uphill and downhill stroke adjustments to judge pace on that green's speed. FAQ: Q: What is a Stimpmeter? A: A Stimpmeter is a simple grooved aluminium ramp that releases a golf ball at a fixed speed. The distance the ball rolls on a flat green, measured in feet, is the green speed reading, with higher numbers meaning faster greens. Q: What Stimpmeter readings are slow, medium, and fast? A: Roughly, under 7 feet is slow, 7 to 9 is medium, 9 to 11 is fast, and above 11 is tour-fast. Most everyday club greens sit between 8 and 10 feet, while major championship greens often run 12 feet or more. Q: How does green speed change my putting? A: On faster greens you make a shorter, softer stroke for the same distance, and break plays a bigger role because the ball is moving more slowly near the hole. On slower greens you must hit firmer and allow for less break. Q: Why measure on a flat section? A: Slope corrupts the reading because gravity speeds up or slows the ball. The Stimpmeter protocol rolls balls in two opposite directions on a level area and averages them to cancel out any residual slope and wind. Q: Do the uphill and downhill adjustments depend on speed? A: Yes. The faster the green, the more a downhill putt runs out and the more an uphill putt dies, so the pace adjustment grows with speed. The tool scales the suggested stroke change with the Stimpmeter reading. #### Milling Horsepower Calculator URL: https://geratools.com/milling-horsepower-calculator Estimates the spindle power needed for a milling cut from the material removal rate, a material-specific unit power or specific cutting force, and a machine efficiency factor. Works in horsepower or kilowatts and warns when the required power exceeds the machine rating. Runs in your browser. How to use: 1. Set units and material: Choose horsepower or kilowatts, then pick the workpiece material to load its unit power or specific cutting force. 2. Enter the cut geometry: Type the width of cut, depth of cut, feed rate, and a machine efficiency factor such as 0.8. 3. Read required power: The tool shows the material removal rate, power at the cutter, and the spindle power required, and warns if it exceeds your machine rating. FAQ: Q: How is milling horsepower calculated? A: Power equals the material removal rate multiplied by the material's unit power, then divided by the machine efficiency to get spindle power. The removal rate is the width of cut times the depth of cut times the feed rate, so harder materials and heavier cuts both raise the power demand. Q: What is unit power or specific cutting force? A: Unit power is the horsepower needed to remove one cubic inch of material per minute, and specific cutting force Kc is its metric equivalent in newtons per square millimetre. It depends mostly on the material, ranging from about 0.25 for aluminium to roughly 1.4 for stainless and titanium. Q: Why divide by machine efficiency? A: The cutting action needs a certain power at the tool, but the motor also loses energy to belts, bearings, and the drive. Dividing the cutting power by an efficiency factor, typically 0.75 to 0.9, gives the larger power the spindle motor must actually deliver. Q: What if the required power exceeds my machine? A: If the result is above your spindle rating, the cut will bog down, stall, or trip the overload. Reduce the depth of cut, the width of cut, or the feed rate to lower the removal rate, or take the cut in multiple lighter passes. The tool flags this when you enter your machine rating. Q: How accurate are the numbers? A: These are typical averages, so treat the result as a feasibility check rather than an exact figure. Sharp, properly coated tooling cuts the power need, while dull tools, small radial engagement, and high-temperature alloys raise it. Always leave headroom below the machine's rating. #### NHTSA Vehicle Make & Model Lookup URL: https://geratools.com/nhtsa-make-model-lookup Look up every vehicle make and model in the official NHTSA vPIC database. Pick a vehicle type and year, browse manufacturers, then drill into the full model list — live from NHTSA, keyless, and free, right in your browser. How to use: 1. Choose a vehicle type: Select the vehicle type (car, truck, motorcycle, bus, trailer, MPV, or low-speed vehicle) to load the matching list of manufacturers from NHTSA. 2. Pick a make and year: Choose a manufacturer from the populated dropdown and select the model year you are interested in. 3. Get the models: Press "Get models" to fetch the full list of models that NHTSA records for that make and year. FAQ: Q: Where does the data come from? A: Every result comes live from the official NHTSA vPIC API (vpic.nhtsa.dot.gov). The tool fetches directly from your browser, so the data is always as current as NHTSA's database. Q: Do I need an API key? A: No. The NHTSA vPIC API is a free, public, keyless government service. This tool calls it directly from your browser with no registration, no key, and no cost. Q: Why are some makes missing for a vehicle type? A: NHTSA groups makes by the vehicle types they actually produce. A motorcycle-only brand will not appear under car, and a make appears under a type only if NHTSA has at least one record linking them. Q: Why does a make return no models for a year? A: NHTSA only returns models it has on file for that exact make and model year. If a make did not sell that year, or NHTSA has no record, the list comes back empty. Try an adjacent year. Q: Can I use this to build other VIN tools? A: Yes. The same vPIC endpoints power VIN decoders and validators. You can use this lookup to confirm the exact make and model spelling NHTSA expects before feeding them into other vehicle tools. #### Plasma Cut Speed Calculator URL: https://geratools.com/plasma-cut-speed-calculator Estimates recommended plasma cut speed in inches per minute for mild steel, stainless, and aluminum from material thickness and plasma cutter amperage, using manufacturer-derived cut-speed curves. Flags speeds that risk dross, undercut, or incomplete penetration. Runs in your browser. How to use: 1. Choose the material: Select mild steel, stainless steel, or aluminum. Each has its own cut-speed curve because thermal conductivity differs. 2. Enter thickness and amperage: Type the plate thickness and your plasma cutter's output amperage. The tool interpolates a recommended cut speed from manufacturer-style curves. 3. Read the recommended speed: The tool returns a target inches-per-minute speed and warns if the amperage is too low to pierce the chosen thickness. FAQ: Q: How does amperage affect cut speed? A: Higher amperage delivers more energy to the arc, so it can melt and blow away metal faster, allowing higher travel speeds at a given thickness. It also raises the maximum thickness the torch can sever. Too little amperage for the thickness leaves dross or fails to cut through. Q: What is dross and how does speed control it? A: Dross is re-solidified metal stuck to the cut edge. Going too slow lets molten metal pool and form low-speed dross on top; going too fast leaves high-speed dross on the bottom and an angled, lagging cut. The right speed produces a clean, near-vertical edge with minimal dross. Q: Why is aluminum cut differently from steel? A: Aluminum conducts heat away from the cut zone much faster than steel, so it generally needs higher current or slower speed for the same thickness. Stainless behaves between the two and benefits from higher current and sometimes specialty gases for clean edges. Q: What happens if I cut too fast? A: Too fast and the arc lags behind, leaving an incomplete cut or a V-shaped bevel that does not penetrate the bottom. You will see sparks blowing back up toward the torch instead of out the bottom, a sign to slow down or raise amperage. Q: Are these speeds exact for my machine? A: They are manufacturer-style estimates and a strong starting point. Exact speeds depend on your torch, consumables, gas, voltage, and pierce height. Always run a test cut and fine-tune for a square edge and clean bottom before production. #### True Airspeed (TAS) Calculator URL: https://geratools.com/true-airspeed-calculator Convert calibrated or indicated airspeed to true airspeed using pressure altitude and outside air temperature, with density altitude shown. Pilots use it for flight planning, nav-log construction, and wind-correction-angle work. Runs in your browser. How to use: 1. Enter your airspeed: Type the calibrated airspeed from your airspeed indicator. If you only have indicated airspeed, correct it for instrument and position error first. 2. Add altitude and temperature: Enter the pressure altitude in feet and the outside air temperature in degrees Celsius, both read from your instruments in cruise. 3. Read true airspeed: The tool returns true airspeed along with the density altitude and density ratio used in the conversion, ready for your nav log. FAQ: Q: Why is true airspeed higher than indicated airspeed? A: As you climb, the air thins, so the airspeed indicator under-reads because it senses dynamic pressure from fewer air molecules. True airspeed corrects for this lower density, so it grows roughly two percent for every thousand feet of density altitude. Q: What is the difference between pressure and density altitude? A: Pressure altitude is what your altimeter shows with the setting at 29.92. Density altitude further corrects pressure altitude for temperature, and it is density altitude that actually drives the airspeed correction and aircraft performance. Q: Should I enter indicated or calibrated airspeed? A: Enter calibrated airspeed for best accuracy. Calibrated airspeed is indicated airspeed corrected for the instrument and position error listed in your aircraft flight manual, which can be a few knots at the speeds where it matters. Q: How accurate is this compared to an E6B? A: It uses the same density-ratio physics as a mechanical or electronic flight computer and matches it within a knot or two across normal general-aviation altitudes and temperatures. The rule-of-thumb figure is also shown for a quick mental cross-check. Q: Does this account for compressibility at high speed? A: No. The simple density correction is accurate for typical piston and turboprop speeds. Above roughly 200 knots and high altitude a small compressibility correction applies, which jet flight computers add separately. #### VIN Model Year Decoder URL: https://geratools.com/vin-model-year-decoder Decode the model year from VIN position 10 using the NHTSA repeating alpha-numeric cycle. Handles the 1980-onward sequence correctly, skips the excluded letters I, O, Q, U, Z, and 0, and shows both 30-year candidates, disambiguating with position 7 where possible. Runs in your browser. How to use: 1. Enter the position 10 character: Type the single 10th character of the VIN, or paste the whole VIN and the tool reads position 10 for you. 2. See both candidate years: Because the code repeats every 30 years, the tool shows both possible years for that character, such as 1989 and 2019. 3. Disambiguate with position 7: For VINs from 2010 onward, position 7 is a letter, while older ones use a digit. The tool uses this to pick the correct year automatically when it can. FAQ: Q: How does VIN position 10 encode the year? A: Position 10 cycles through a fixed sequence of letters and digits, one per model year. It started with A for 1980, runs through Y for 2000, then uses digits 1 to 9 for 2001 to 2009, and restarts at A for 2010, repeating every 30 years. Q: Which letters are skipped? A: The model year code never uses I, O, Q, U, Z, or the digit 0, because they are confused with other characters. So the letter sequence runs A B C D E F G H J K L M N P R S T V W X Y, then digits 1 through 9. Q: Why are there two possible years? A: The cycle repeats every 30 years, so the same character means, for example, both 1989 and 2019. A single character cannot tell them apart, which is why the tool shows both candidates and tries to narrow it down. Q: How does position 7 break the tie? A: Since the 2010 model year, manufacturers were required to make position 7 a letter for vehicles 2010 and newer, and a number for 1980 to 2009. The tool reads position 7 from a full VIN to choose the correct 30-year cycle when possible. Q: Does the model year match the calendar year? A: Not exactly. A model year vehicle is often built and sold starting the autumn before its model year, so a car built in late 2023 can carry a 2024 model year. Position 10 encodes the model year, not the manufacture date. #### VIN Structure Decoder URL: https://geratools.com/vin-structure-decoder Split a 17-character VIN into the World Manufacturer Identifier (positions 1–3), Vehicle Descriptor Section (4–9), and Vehicle Identifier Section (10–17). Each character is labelled by role — manufacturer, check digit, model year, plant, serial — with a built-in WMI lookup for common makers. Runs in your browser. How to use: 1. Enter the VIN: Paste the full 17-character VIN. Case does not matter and spaces are ignored. 2. See the three sections: The tool splits the VIN into WMI, VDS, and VIS and colours each block so you can see where one section ends and the next begins. 3. Read each character's role: Hover or read the table to see what every position means, including the check digit, model year, and assembly plant. FAQ: Q: What are the WMI, VDS, and VIS sections? A: The WMI is positions 1 to 3 and identifies the manufacturer and country. The VDS is positions 4 to 9 and describes the vehicle attributes plus the check digit. The VIS is positions 10 to 17 and carries the model year, plant code, and serial number. Q: Which character is the manufacturer? A: Positions 1 to 3 form the World Manufacturer Identifier. The first character is the region and country, the second narrows the manufacturer, and the third often indicates the vehicle type or division. The tool looks up common WMIs by name. Q: Where is the model year in a VIN? A: Position 10 encodes the model year on a 30-year repeating cycle. Position 11 is usually the assembly plant. The tool labels both, and a separate model-year decoder resolves the exact year from that single character. Q: What is the serial number portion? A: The last several characters of the VIS, typically positions 12 to 17, are the sequential production serial that uniquely identifies the individual unit coming off the line. They are assigned in build order by the plant. Q: Does this work for motorcycles and trucks? A: The WMI, VDS, VIS structure is standardized for all road vehicles built to ISO 3779, including motorcycles and heavy trucks. The position roles are the same, though manufacturers vary in how they pack attributes into the VDS. #### Ackermann Angle Calculator URL: https://geratools.com/ackermann-angle-calculator Free Ackermann steering geometry calculator. Enter wheelbase, track width, outer steer angle and Ackermann percentage to get the ideal inner wheel angle, actual inner angle, scrub angle, turning radius and a live geometry diagram. 100% client-side. How to use: 1. Enter wheelbase and track width: Type your vehicle wheelbase (centre of front axle to centre of rear axle) and track width (centre of left tyre to centre of right tyre) in millimetres. 2. Set the outer wheel steer angle: Enter the steer angle of the outer (lightly-loaded, larger-radius) front wheel in degrees. This is the wheel on the outside of the turn. 3. Choose an Ackermann percentage: 0% is parallel steer (both front wheels point the same direction). 100% is full Ackermann (ideal geometry, zero scrub). Values above 100% are pro-Ackermann used in some racing applications. 4. Read the results: The calculator shows the ideal inner wheel angle, the actual inner angle for your chosen Ackermann percentage, the scrub angle, turning radius to the rear axle centre, and inner/outer wheel radii. The diagram updates in real time. FAQ: Q: What is Ackermann steering geometry? A: Ackermann geometry is a steering layout where the inner and outer front wheels turn at different angles so that both wheels trace concentric circles around a common centre point. Because the inner wheel follows a tighter arc, it must turn more than the outer wheel. Without this differential, at least one tyre is forced to scrub sideways, generating heat, wear and understeer. Q: What is the Ackermann steering formula? A: The standard cotangent form is: cot(delta_outer) minus cot(delta_inner) equals T divided by L, where T is the track width and L is the wheelbase. Rearranging gives the ideal inner angle: delta_inner = arccot(cot(delta_outer) minus T/L). The turning radius to the rear axle midpoint is R = L divided by tan(delta_outer). Q: What does Ackermann percentage mean? A: 0% Ackermann means both front wheels steer the same angle (parallel steer). 100% means the inner wheel is at the exact ideal angle for zero tire scrub. Values between 0% and 100% are a blend; many road cars sit at 70-90%. Racing cars sometimes use over 100% (pro-Ackermann) to compensate for tyre slip angles at high cornering loads. Q: What is a scrub angle? A: The scrub angle is the difference between the actual inner wheel angle and the ideal (100% Ackermann) inner wheel angle. A scrub angle of zero means no lateral sliding of the tyre contact patch during a steady-state turn. Even small scrub angles add up over many laps or kilometres, causing uneven tyre wear and raising tyre temperatures. Q: How does wheelbase affect Ackermann geometry? A: A longer wheelbase relative to track width reduces the required difference between inner and outer steer angles, making the geometry easier to achieve mechanically. Shorter wheelbase vehicles (karts, city cars) need a larger inner/outer angle split to maintain ideal Ackermann, which is why kart steering geometry is a common teaching example. Q: Is this calculator accurate for real vehicle design? A: Yes for steady-state kinematic geometry. The formula assumes rigid links, symmetric geometry and no tyre slip. Dynamic effects (compliance steer, tyre slip angles, roll steer, kingpin inclination) require full multi-body simulation software such as ADAMS or OptimumK. This tool is ideal for first-pass suspension layout, race car setup benchmarking and education. #### Engine CC to HP Calculator URL: https://geratools.com/engine-cc-to-hp-calculator Free engine CC to HP calculator. Convert cubic centimetres to horsepower, kW, PS and torque using specific-output, BMEP, cc/hp rule-of-thumb, and thermodynamic methods. Supports naturally aspirated, turbocharged, diesel, two-stroke and classic engines. How to use: 1. Enter your engine displacement: Type the engine size in cubic centimetres (cc). For example, a 2.0-litre engine is 2000 cc. 2. Select the engine type: Choose from naturally aspirated, turbocharged, diesel, two-stroke, vintage, or high-rev NA. Each preset uses real-world BMEP and specific-output figures from that class of engine. 3. Override RPM or hp/L if known: If you know the peak-power RPM or the manufacturer quoted specific output, enter them to sharpen the BMEP and thermodynamic estimates. 4. Read the consensus estimate: The calculator averages three independent methods and shows each method's breakdown so you can see how closely they agree. 5. Copy results: Hit the Copy button to export all four method results, torque, kW, PS and conversion figures to your clipboard. FAQ: Q: How is engine displacement related to horsepower? A: Displacement sets the upper limit on how much air-fuel mixture can be burned per cycle, which in turn caps the potential power. The relationship is not fixed — a 2000 cc naturally-aspirated engine might produce 120 hp while a 2000 cc turbocharged engine produces 300 hp, because boost pressure allows far more air (and fuel) to be packed into the same swept volume. Specific output (hp per litre) is the usual benchmark. Q: What is BMEP and why does it matter? A: Brake Mean Effective Pressure (BMEP) is the average pressure acting on each piston during the power stroke, expressed in kPa. It is a direct measure of how efficiently an engine uses its displacement. A naturally-aspirated petrol engine achieves roughly 900–1200 kPa BMEP; a highly-boosted turbo can reach 2000–3000 kPa. The formula HP = (BMEP × V × N) / (strokes-per-cycle × 60) gives the shaft power for any known BMEP and RPM. Q: How accurate are these estimates? A: Accuracy varies by method. The specific-output method gives a ±15–25% range because hp/L spans ~55–80 for stock NA engines. The BMEP method is tighter if you know the engine class well. The thermodynamic method depends on efficiency assumptions. Real dyno figures can differ from all estimates because of intake/exhaust tuning, compression ratio, combustion chamber design and production tolerances. Use the consensus of three methods as a reasonable central estimate, not a dyno result. Q: What is the difference between hp, kW, and PS? A: They are all units of power measuring the same physical quantity, just scaled differently. 1 mechanical horsepower (hp) = 0.7457 kW. 1 PS (Pferdestärke, metric horsepower) = 0.7355 kW = 0.9863 hp. European car manufacturers historically quote PS; US and UK manufacturers quote hp. Differences of 1–2% mean the numbers are nearly interchangeable at low precision. Q: Why do two-stroke engines produce more hp per cc? A: A two-stroke engine fires on every revolution rather than every other revolution, so it delivers twice as many power strokes per minute as a four-stroke of the same displacement and RPM. This doubles the theoretical power density. In practice two-strokes sacrifice efficiency (some fresh charge escapes during scavenging), but well-tuned competition two-strokes can reach 200+ hp/L — figures impossible for four-strokes without extreme boost. Q: How do I convert cc to litres and cubic inches? A: Dividing cc by 1000 gives litres: 1998 cc = 1.998 L. Dividing cc by 16.387 gives cubic inches: 1998 cc = 121.9 cu in. Engine capacity on US-market vehicles is often quoted in litres rounded to one decimal (e.g. 2.0L) or historically in cubic inches (e.g. 302 cu in = 4.9L). #### Engine Displacement Calculator URL: https://geratools.com/engine-displacement-calculator Free engine displacement calculator using V = (π/4) × bore² × stroke × cylinders. Solve for displacement (cc, litres, cubic inches), bore, stroke, or number of cylinders. Also computes compression ratio and bore:stroke ratio. 100% client-side. How to use: 1. Choose what to solve for: Use the "Solve for" dropdown to pick displacement, bore, stroke, or cylinder count. 2. Enter the known dimensions: Type bore and stroke in millimetres and the number of cylinders. Use decimal values for precision. 3. Pick your output unit: Switch between cc (cm³), litres, or cubic inches to match your spec sheet. 4. Add clearance volume for compression ratio: Optionally enter the combustion-chamber clearance volume per cylinder in cc to get the compression ratio alongside the displacement result. FAQ: Q: What is the engine displacement formula? A: Displacement V = (π/4) × bore² × stroke × cylinders. Bore and stroke must be in the same unit; converting mm to cm first gives the result directly in cc (cm³). To get litres divide by 1,000; to get cubic inches divide by 16.387. Q: What is a square, over-square, or under-square engine? A: When bore equals stroke the engine is square. A bore larger than the stroke (bore:stroke ratio above 1) is over-square — typically high-revving and found in sports cars and motorcycles. A bore smaller than the stroke (ratio below 1) is under-square or long-stroke — producing more torque at lower RPM and common in diesel and truck engines. Q: How is compression ratio calculated? A: Compression ratio CR = (swept volume + clearance volume) / clearance volume, where swept volume is displacement divided by the number of cylinders. For example a 500 cc per-cylinder engine with a 50 cc clearance chamber gives CR = (500 + 50) / 50 = 11:1. Higher CR generally means more efficiency and power but requires higher-octane fuel. Q: How do I convert engine displacement from cc to litres? A: Divide by 1,000. A 1,998 cc engine is a 2.0 litre engine. Manufacturers often round to one decimal place — a "2.0L" engine may actually be 1,984 cc or 1,998 cc depending on the bore/stroke combination chosen. Q: How do I convert cc to cubic inches? A: Divide by 16.387064. A 5,700 cc (5.7L) engine is approximately 347.8 cubic inches, often marketed as a "350" in American muscle-car tradition (slightly rounded). Q: Why does engine displacement affect power? A: Larger displacement means more air and fuel can be burned per cycle, producing more torque and — when multiplied by RPM — more power. However, how that displacement is achieved matters: an over-square engine with a short stroke can rev higher and gain power at the top end, while an under-square long-stroke engine delivers peak torque lower in the rev range. #### Quarter-Mile Calculator URL: https://geratools.com/quarter-mile-calculator Free quarter-mile drag racing calculator. Enter your car's weight and horsepower to predict elapsed time (ET) and trap speed using the Wallace/NHRA formula. Solve for HP or weight to hit a target ET. 100% client-side — no data is uploaded. How to use: 1. Enter your vehicle weight: Type the kerb weight (plus driver and fuel) in pounds or kilograms. For a street car include everything that will be on the track. 2. Enter your flywheel horsepower: Use the manufacturer peak horsepower figure, or a dyno-measured number. Wheel horsepower is typically 15-20% lower than flywheel — adjust accordingly. 3. Read the predicted ET and trap speed: The calculator instantly shows your quarter-mile elapsed time in seconds and your trap speed in mph using the Wallace formula. 4. Solve in reverse: Switch the "Solve for" selector to find what horsepower you need for a target ET, or how much weight you must shed. 5. Check the HP scenarios table: Expand the scenarios table to see how ET and trap speed change across a range of horsepower values at the same weight. FAQ: Q: What formula does this calculator use? A: It uses the Wallace/NHRA rule-of-thumb: ET = 5.825 × (Weight ÷ HP)^(1/3) and Trap Speed = 234 × (HP ÷ Weight)^(1/3). Roger Huntington popularised these in the 1960s and they remain the standard back-of-envelope method used by NHRA bracket racers and engine builders worldwide. Q: How accurate is the Wallace formula? A: For well-prepared rear-wheel-drive cars on slicks in ideal conditions it is accurate to within 0.2–0.5 seconds. Street cars on radials typically run 0.3–0.6 s slower than predicted due to traction loss. Altitude, temperature, humidity, and drivetrain type (manual vs automatic) all shift the result. Q: Should I use flywheel or wheel horsepower? A: The formula was calibrated against flywheel (crankshaft) horsepower, so use that if you have a dyno sheet or manufacturer spec. If you only have a wheel-horsepower figure, divide it by 0.83 (assuming 17% drivetrain loss for a rear-wheel-drive car) to estimate flywheel HP before entering it. Q: What is a good quarter-mile time for a street car? A: A stock family saloon typically runs 15–17 s. A hot hatch or muscle car runs 13–15 s. A modified performance car hits 11–13 s. Under 10 s requires serious engine work; under 9 s demands a full drag build. The calculator labels your predicted time with a performance class so you can see at a glance where you stand. Q: Can I use kilograms instead of pounds? A: Yes. Select "kg" next to the weight field and the calculator converts to pounds internally before applying the formula. Results are still shown in seconds and mph because the Wallace constants are calibrated to imperial units. Q: How is the 60-foot time estimated? A: The 60-ft time shown is an approximation: ET ÷ 5.5. This is a rough rule of thumb used in bracket racing. Real 60-ft times depend heavily on launch technique, tyre prep, and traction — a good launch can be 0.5 s faster than a poor one even at identical overall ET. #### Boost Pressure Calculator URL: https://geratools.com/boost-pressure-calculator Free turbocharger and supercharger boost pressure calculator. Convert psi, bar, kPa and atm; calculate pressure ratio (PR); model post-compressor charge temperature and density using isentropic efficiency; check injector duty cycle at any RPM and AFR. No data leaves your device. How to use: 1. Choose what to calculate: Pick a mode: pressure ratio from boost, gauge boost from a target PR, implied ambient from PR plus gauge, charge-air temperature/density, or injector duty cycle. 2. Enter ambient and gauge boost: Type your ambient (atmospheric) pressure and your boost gauge reading. Select the units that match your instruments — psi, bar, kPa or atm. 3. Read the absolute pressure and PR: The calculator immediately shows manifold absolute pressure (MAP) in all four units and the dimensionless pressure ratio used on compressor maps. 4. Model charge-air heating (optional): Switch to the density mode, add ambient temperature and isentropic compressor efficiency to see post-compressor charge temperature and the resulting density ratio — with and without an intercooler. 5. Check injector sizing (optional): In the fuelling mode enter displacement, target AFR, injector size, VE and RPM to get duty cycle as a percentage and a clear over/under warning. FAQ: Q: What is the difference between gauge boost and absolute pressure? A: Boost gauges read relative to ambient (gauge pressure). Absolute pressure (MAP) is gauge plus ambient: MAP = P_gauge + P_ambient. At sea level (14.696 psi / 1.01325 bar) 15 psi gauge = 29.7 psi absolute. Pressure ratio (PR = MAP / P_ambient) is always based on absolute values. Q: What is pressure ratio and why does it matter? A: Pressure ratio is the dimensionless number that characterises compressor work: PR = P_absolute_out / P_absolute_in. It appears on every compressor map and determines adiabatic temperature rise, efficiency islands and surge/choke boundaries. Two cars running "15 psi boost" at different altitudes have different PRs and therefore different power outputs. Q: How is post-compressor charge temperature calculated? A: The isentropic (ideal) temperature rise is T₂_isen = T₁ × PR^((γ−1)/γ), where γ ≈ 1.4 for air and T₁ is the inlet temperature in Kelvin. A real compressor is less than 100 % efficient so the actual outlet temperature is T₂_real = T₁ + (T₂_isen − T₁) / η_c, where η_c is isentropic efficiency (typically 65–80 %). Hot charge air is less dense, so a good intercooler recovers density even after the pressure rise. Q: What is charge-air density ratio and how does it affect power? A: Density ratio = PR × (T_ambient / T_outlet). Because power scales with air mass rather than air volume, density ratio directly predicts the power multiplier relative to naturally-aspirated. A density ratio of 1.7 means roughly 70 % more air mass per intake stroke — and therefore roughly 70 % more potential power before other limits (knock, fuelling, exhaust) come into play. Q: What injector duty cycle is safe? A: The standard rule is to keep static duty cycle at or below 80 % at the RPM and load point you are targeting. This leaves headroom for ECU short-term fuel trims (typically ±15–25 %), injector-to-injector variation and gradual flow degradation over time. Above 85 % the ECU may clip fuelling and the mixture leans out unpredictably — a serious risk of detonation and engine damage. Q: How do I convert between psi, bar and kPa? A: 1 psi = 0.0689476 bar = 6.894757 kPa = 0.068046 atm. The calculator converts all inputs and outputs in real time, so you can enter bar and read psi or vice versa without touching a spreadsheet. #### Gear Ratio & Speed Calculator URL: https://geratools.com/gear-ratio-speed-calculator Free gear ratio and speed calculator: enter your transmission ratios, final drive, tyre size and engine RPM to get exact vehicle speed in mph and km/h — or solve backwards for RPM, gear ratio, final drive or tyre diameter. Runs entirely in your browser. How to use: 1. Choose a vehicle preset or enter your own ratios: Pick from the built-in economy hatchback, sports car or pick-up truck presets, or type your own transmission gear ratios directly into the gear cards. 2. Enter your tyre size: Switch to P-metric mode and type width, aspect ratio and rim diameter (for example 225/45R18), or toggle to manual mode and enter the outer diameter in inches directly. 3. Set the final drive ratio and engine RPM: Enter your axle or differential ratio and the RPM you want to evaluate — for example 3000 RPM for a cruise check or redline RPM for a top-speed estimate. 4. Read the full gear-speed table: The calculator instantly shows speed in both mph and km/h for every gear in your transmission. Click any gear card to highlight it and see the individual working. 5. Solve backwards if needed: Change the "Solve for" selector to find the RPM for a target speed, the transmission ratio you need, the ideal final drive, or the tyre diameter required for a specific gearing target. FAQ: Q: What is the gear ratio speed formula? A: Speed (mph) = (Engine RPM × π × tyre diameter in inches) / (transmission gear ratio × final drive ratio × 1056). The constant 1056 comes from unit conversion: 12 inches per foot × 5280 feet per mile / 60 minutes = 1056. Divide by 1.60934 to convert to km/h. Q: What is the difference between gear ratio and final drive ratio? A: The transmission gear ratio is the ratio inside the gearbox for a particular gear (e.g. 1st gear might be 3.46:1). The final drive ratio is the fixed ratio in the differential or axle (e.g. 3.73:1). The overall ratio that the engine "sees" is the product of both: 3.46 × 3.73 = 12.91:1 in this example. Q: How do I find my car's gear ratios? A: Gear ratios are listed in the vehicle's workshop manual, on manufacturer specification sheets, or on enthusiast forums specific to your model. You can also measure them empirically by recording engine RPM and road speed in a known gear on a flat road, then back-calculating using this calculator's 'Solve for gear ratio' mode. Q: How does tyre size affect speed calculations? A: A larger tyre diameter means more distance per wheel revolution, so at the same RPM the vehicle moves faster. A P-metric size like 225/45R18 decodes as: section width 225 mm, sidewall = 225 × 0.45 = 101.25 mm each side, overall diameter = 18 inches + (2 × 101.25 / 25.4) = 25.97 inches. Even a 10 mm change in overall diameter shifts top speed and cruise RPM by roughly 1–2%. Q: What is a numerically high vs low final drive ratio? A: A numerically high final drive (e.g. 4.30:1) multiplies torque more at the wheels, giving stronger acceleration but higher engine RPM at any given road speed. A numerically low ratio (e.g. 2.73:1) reduces torque multiplication but lowers cruise RPM, improving fuel economy. Long-ratio gearing suits motorway cruisers; short-ratio suits towing or track use. Q: Can I use this for motorcycles or trucks? A: Yes. The underlying formula (speed = RPM × π × tyre diameter / (gear ratio × final drive × 1056)) is universal for any wheeled vehicle. For a motorcycle with a chain-drive primary and secondary reduction, multiply all ratios together to get the overall ratio, then enter that as a single-gear transmission with a final drive of 1:1 — or split them across the two fields. #### Volumetric Efficiency Calculator URL: https://geratools.com/volumetric-efficiency-calculator Free volumetric efficiency calculator for petrol and diesel engines. Use MAP/speed-density, MAF sensor, direct volume, or BHP+BSFC methods. Shows VE %, air density, and a reference band. 100% client-side — no data uploaded. How to use: 1. Choose a calculation method: Pick MAP/speed-density if you have a manifold pressure sensor and IAT reading; MAF mode if you have a mass-airflow sensor log; direct volume if you have flowbench data; or BHP+BSFC if you only have a dyno sheet. 2. Enter engine displacement: Type the total swept volume of your engine in cubic centimetres (cc). You can find this in the engine spec sheet or calculate it from bore, stroke, and cylinder count. 3. Fill in the method-specific inputs: For MAP mode enter manifold absolute pressure in kPa and intake air temperature in Celsius. For MAF mode add the sensor reading in g/s and engine RPM. For the volume method enter the measured air volume per cycle from your flowbench. 4. Read the VE percentage and band: The tool shows volumetric efficiency as a percentage, colour-coded against standard bands from "below average" up to "forced induction". Copy the full results with one click. FAQ: Q: What is volumetric efficiency? A: Volumetric efficiency (VE) is the ratio of the actual mass of air an engine draws into the cylinders in one intake stroke to the theoretical maximum it could draw if the cylinders filled perfectly at ambient (or standard) conditions. A naturally-aspirated engine at 100 % VE would fill every cubic centimetre of swept volume with air at exactly atmospheric density. Real engines range from about 75 % (worn or restricted) up to around 95–98 % for a well-built high-performance unit. Turbocharged engines exceed 100 % because the forced induction pumps in more air than the cylinder can physically hold at atmospheric pressure. Q: What is the difference between MAP/speed-density and MAF methods? A: The MAP (speed-density) method infers how much air is entering the engine from the manifold absolute pressure, intake air temperature, and the ideal-gas law. It needs no flow sensor but assumes the plenum is close to the measured pressure. The MAF (mass airflow) method reads an actual flow sensor — typically a hot-wire anemometer — which measures the air mass directly as it passes the sensor. MAF is more accurate for transient conditions and is the basis for most modern fuel-injection ECUs. Both give the same answer on a well-tuned engine; discrepancies reveal vacuum leaks, sensor drift, or sensor placement issues. Q: Why does the MAP formula use the ideal-gas law? A: Air is close enough to an ideal gas at the pressures and temperatures found in an intake manifold that the ideal-gas law (PV = nRT) gives an accurate density. The formula here is: rho = (P × M_air) / (R × T), where P is absolute pressure in kPa, M_air is the molar mass of dry air (28.97 g/mol), R is the universal gas constant (8.314 J/(mol·K)), and T is temperature in Kelvin. The result is air density in g/L. Comparing this to the standard reference density (1.225 g/L at 15 °C and 101.325 kPa) gives VE directly. Q: What VE is considered good for a naturally-aspirated engine? A: A typical factory NA engine achieves 75–85 % VE across its rev range. A well-prepared performance engine with ported cylinder head, matched intake, and a well-profiled camshaft can reach 90–95 % at its VE peak. Values above 95 % for a pure NA engine are exceptional and usually only seen on race-prepared units at a narrow RPM window near peak torque. Anything below 70 % suggests a restriction — collapsed air-filter, leaking head gasket, bent valves, or extreme intake runner mismatch. Q: Can a turbocharged engine have more than 100% VE? A: Yes — and that is the whole point of forced induction. By compressing the intake charge before it enters the cylinder, a turbo or supercharger raises the density of the air above atmospheric, so the engine draws in more mass per cycle than the swept volume would allow at ambient conditions. A modestly boosted engine might reach 130–160 % VE; a heavily boosted drag engine can exceed 200 %. The formula is the same: VE = (actual air mass) / (theoretical air mass at standard conditions) × 100. Values above 100 % simply mean the engine is force-fed. Q: How does VE relate to power output? A: More air in the cylinder means more fuel can be burned and more power produced. Power scales almost linearly with VE at a fixed displacement, RPM, and air-fuel ratio. That is why engine tuners focus heavily on VE — improving it from 82 % to 90 % is roughly equivalent to an 8-10 % power increase with no other changes. Cam timing, port shape, valve size, intake runner length, and exhaust scavenging all directly affect VE. ### Music & Audio #### Audio Buffer Size & Latency Calculator URL: https://geratools.com/audio-latency-buffer-size Compute input, output, and round-trip audio latency in milliseconds from buffer size (64 to 4096 samples) and sample rate. Helps producers and live performers choose the right ASIO or Core Audio buffer size for low-latency monitoring without audio dropouts. How to use: 1. Enter your buffer size: Pick the buffer size your audio interface or DAW is set to, in samples (commonly 64, 128, 256, 512, or 1024). 2. Set the sample rate: Choose your project sample rate, such as 44100 or 48000 Hz. Higher rates lower latency for the same buffer size. 3. Read the latency: The tool shows the one-way buffer latency and an estimated round-trip latency including converter delay. FAQ: Q: How is buffer latency calculated? A: Buffer latency in milliseconds equals buffer size in samples divided by sample rate in Hz, times 1000. A 128-sample buffer at 48000 Hz is 128/48000 times 1000, which is 2.67 ms for one buffer pass. Q: What is round-trip latency? A: Round-trip latency is the total delay from a sound entering the interface to the processed sound coming back out. It includes the input buffer, the output buffer, and analog-to-digital plus digital-to-analog converter delay. A common approximation is twice the buffer latency plus a small fixed converter overhead. Q: Does a higher sample rate reduce latency? A: Yes, for the same buffer size in samples. At 96000 Hz a 128-sample buffer is 1.33 ms versus 2.67 ms at 48000 Hz, because each sample represents less time. The trade-off is roughly double the CPU load and disk throughput. Q: What buffer size should I use for recording versus mixing? A: Use a small buffer (64 to 128 samples) when recording or monitoring through plugins, so latency stays under about 6 ms and feels immediate. Switch to a large buffer (512 to 1024 samples) when mixing, where latency does not matter but you need the CPU headroom for many plugins. Q: At what point does latency become noticeable? A: Most players notice round-trip latency above roughly 10 ms, and it becomes disruptive above 20 to 30 ms, similar to standing a few metres from a speaker. Under about 6 ms feels effectively instant. Singers and percussionists are the most sensitive. #### Theoretical Noise Floor by Bit Depth Calculator URL: https://geratools.com/audio-noise-floor-db Compute the theoretical dynamic range in dB and quantisation noise floor in dBFS for audio bit depths from 8 to 32 bits using the 6.02 dB per bit rule, with the full 6.02n + 1.76 SQNR figure. Explains why 24-bit is enough for any audio work. Runs 100% in your browser. How to use: 1. Enter a bit depth: Type a value such as 16, 24, or 32, or pick a common depth from the dropdown. 2. Read the dynamic range: The calculator shows the theoretical dynamic range in dB using both the full and simplified formulas. 3. Check the noise floor: The noise floor in dBFS is shown — this is how far quantisation noise sits below full scale. FAQ: Q: What is the dynamic range of 16-bit audio? A: Using the full formula 6.02 × 16 + 1.76, 16-bit PCM has a theoretical dynamic range of about 98.1 dB. The simplified 6 dB per bit rule gives 96 dB, which is the figure most often quoted for CD audio. Q: What is the 6.02 dB per bit rule? A: Each extra bit halves the quantisation step, which doubles resolution and adds 20·log10(2) ≈ 6.02 dB of dynamic range. So dynamic range scales as 6.02 × bit depth, plus a 1.76 dB term for a full-scale sine wave. Q: What is the noise floor in dBFS? A: The quantisation noise floor sits at the negative of the dynamic range below full scale. For 24-bit that is about −146 dBFS, meaning the smallest representable noise is 146 dB below the loudest signal. Q: Why is 24-bit enough for any audio work? A: 24-bit gives roughly 146 dB of dynamic range, far beyond the ~120 dB range of human hearing and the self-noise floor of any microphone, preamp, or converter. The analog electronics, not the bit depth, set the real noise floor. Q: What is 32-bit float used for then? A: 32-bit floating point provides enormous headroom so you cannot clip during recording or mixing, not lower audible noise. Its huge range protects against accidental overload, after which you reduce gain without losing quality. #### BPM to Delay Time (ms) Calculator URL: https://geratools.com/bpm-delay-ms Converts tempo in BPM to delay times in milliseconds for whole, half, quarter, eighth, sixteenth and beyond, including dotted and triplet variants. Essential for music producers programming delays and echoes that sit in the groove. Runs 100% in your browser. How to use: 1. Enter your project tempo: Type the BPM of your track. This is shown in your DAW's transport bar and drives every delay time in the table. 2. Read the full note-value table: The tool lists straight, dotted, and triplet delay times in milliseconds for every common note division from whole note to sixty-fourth. 3. Dial it into your delay plugin: Copy the millisecond value for the note feel you want, such as the dotted eighth for a classic rhythmic echo, and enter it into your delay unit. FAQ: Q: How do you convert BPM to delay time in milliseconds? A: One beat (a quarter note) lasts 60000 divided by the BPM milliseconds. So at 120 BPM a quarter note is 500 ms. Other note values are simple fractions or multiples of that beat length. Q: What is a dotted eighth delay and why is it popular? A: A dotted eighth note is one and a half times an eighth note, equal to three sixteenths. Set as a delay time it creates the syncopated, galloping echo heard on countless guitar and synth parts. At 120 BPM it is 375 ms. Q: What is the difference between dotted and triplet timing? A: A dotted value is 1.5 times the base note, making it longer; a triplet value is two thirds of the base note, making it shorter and giving a rolling, swung feel. The tool shows both for every division. Q: Should I use these times exactly or round them? A: Use them as close as your plugin allows. Many delays sync to tempo automatically, but for hardware units or free-time plugins entering the exact millisecond value locks the echo to the grid. Q: Does this work for any tempo including odd ones? A: Yes. The formula is purely arithmetic, so it is accurate for any BPM including fractional tempos like 128.5 or unusual ones like 174 used in drum and bass. #### Capo Chord Transposer URL: https://geratools.com/capo-chord-transposer Converts the chord shapes you play with a capo into their true concert-pitch chord names, or works backwards to find the capo position and easy shape that produces a target chord. Built for acoustic guitarists. How to use: 1. Set the capo fret: Choose the fret your capo sits on, from 1 to 11. Fret 0 means no capo and the shape equals the sounding chord. 2. Enter the shape you play: Type the chord shape you finger above the capo, for example G, C, or Em. The tool treats this shape as if the capo were the nut. 3. Read the real chord: The tool shows the concert-pitch chord that actually sounds. Use the reverse mode to find which shape and capo position give a chord you want. FAQ: Q: How does a capo change the chord name? A: A capo raises every string by the number of frets it clamps. So the chord shape you finger sounds higher than its open name by that many semitones. A G shape with a capo on fret 2 actually sounds as an A chord. Q: Does the capo change the chord quality? A: No. Major stays major, minor stays minor, and any added tones such as 7 or sus4 carry over unchanged. A capo only shifts the root pitch up; it never alters the chord type, because the same fingering keeps the same interval structure. Q: How do I work backwards from a target chord? A: Use reverse mode. Enter the concert chord you want and the capo fret, and the tool subtracts the capo's semitones to give the easy open shape you should finger above the capo. This is how players turn awkward keys into open-string shapes. Q: Why do capos make some keys easier? A: Open chord shapes such as G, C, D, E, A, Em and Am use ringing open strings and simple fingerings. A capo lets you keep those friendly shapes while sounding in a harder key like Bb or F#, avoiding barre chords. Q: What is the highest useful capo position? A: Most capos work up to about fret 7 before the strings get too short and the tone thins out. Past fret 7 the playable area shrinks and intonation suffers, so the tool covers frets 1 to 11 but flags that high positions are unusual. #### Compressor Attack & Release to BPM Calculator URL: https://geratools.com/compressor-attack-release-bpm Convert any BPM into musically-aligned compressor attack and release times in milliseconds, from one bar down to a 32nd note. The foundation for pumping sidechain compression and transparent, groove-locked dynamics control in your mix. How to use: 1. Enter the tempo: Type your track's tempo in BPM. Every note-value timing recalculates instantly. 2. Read the release table: The table shows release times for one bar down to a 32nd note, so the gain recovers in time with the groove. 3. Apply attack and release: Pick a release that lets the compressor recover by the next beat, and an attack short enough to catch transients or long enough to let them through. FAQ: Q: How does BPM relate to compressor release time? A: A quarter note lasts 60000 divided by BPM milliseconds. Setting the release to a note value, such as an eighth note, makes the compressor recover its gain right as the next subdivision hits, so the dynamics breathe in time with the music instead of fighting the groove. Q: What release time gives pumping sidechain compression? A: For the classic pumping effect, set the release roughly to a quarter or eighth note so the level dips on each kick and swells back just before the next one. Too short and the pump is inaudible, too long and the track never recovers. Tempo-synced release values are the reliable starting point. Q: How short should compressor attack be? A: A fast attack of 1 to 10 ms clamps transients and makes a sound smaller and more controlled. A slower attack of 20 to 50 ms lets the initial transient punch through before compression engages, which keeps drums and plucks snappy. Attack is usually set by feel rather than tempo. Q: Why sync release to the beat at all? A: An un-synced release can recover at an awkward moment, causing the level to lurch against the rhythm and sound restless. Aligning release to a note value makes each gain recovery land on a musical subdivision, so the compression feels like part of the groove rather than an artefact. Q: Does this apply to limiters and gates too? A: Yes. Gate release and limiter release both benefit from tempo-aware values for the same reason: recovery that lands on the beat sounds intentional. Limiters usually want shorter release than bus compressors to avoid pumping on a master, but the note-value table is still a useful reference. #### Drum Tuning Frequency Calculator URL: https://geratools.com/drum-tuning-frequency Reference fundamental-frequency ranges for kick, snare, and rack and floor toms across pop, rock, jazz, hip-hop, and metal, plus a Hz-to-note identifier. Helps drummers and engineers tune drums to sit in the mix. Runs in your browser. How to use: 1. Choose a genre: Pick the style you are tuning for; each genre shifts the target ranges for kick, snare, and toms. 2. Read the target ranges: The table lists the fundamental-frequency window for each drum and the musical note at the centre of that window. 3. Match a measured pitch: Tap a drum, read its fundamental from a tuner or spectrum app, and enter it to see the nearest note and how many cents sharp or flat it sits. FAQ: Q: What is the fundamental frequency of a drum? A: It is the lowest, strongest pitch the drum produces when struck, which the ear hears as the drum's overall note. Tuning sets this fundamental; the higher overtones from the shell and heads colour the tone around it. Q: What frequency should a kick drum be tuned to? A: It depends on style. Hip-hop and metal kicks sit low, around 40 to 70 Hz for weight, while jazz kicks ring higher at 80 to 110 Hz. Pop and rock land in between. The table gives a range per genre as a starting point. Q: How do I tune drums to a key? A: Read each drum's fundamental with a tuner or spectrum app, then adjust lug tension until the note matches a chord tone of the song's key. The Hz-to-note identifier in this tool tells you the note and how many cents off you are. Q: Why do batter and resonant heads get tuned differently? A: Tuning the resonant head slightly higher or lower than the batter lengthens sustain and adds a pitch glide. Matching them tightens the pitch and shortens decay. Both heads still contribute to the single fundamental you tune toward. Q: Are these frequencies exact targets? A: No, they are practical ranges. Drum size, head choice, depth, and room all move the achievable pitch. Use the ranges to get into the right territory, then fine-tune by ear so each drum sits clearly in the mix. Q: Why does my tuner jump between two readings an octave apart? A: Drums produce strong overtones above the fundamental, and pitch detectors sometimes lock onto the second partial. When readings alternate between values an octave apart, trust the lower one — the fundamental is always the lowest strong partial. Measuring a half-second after the stroke, past the attack transient, also stabilises the reading. #### Equal Temperament vs Just Intonation Comparator URL: https://geratools.com/equal-temperament-vs-just Displays the frequency and cent deviation of every interval in twelve-tone equal temperament against pure just-intonation ratios for any root note. Reveals exactly how much each piano interval is tempered away from a pure harmonic ratio. How to use: 1. Enter the root frequency: Type the frequency of your root note in hertz, or pick a note name. A4 = 440 Hz is the standard concert reference. 2. Read the interval table: Each row shows an interval, its equal-temperament frequency, its pure just-intonation frequency, and how many cents apart they are. 3. Spot the worst offenders: Look at the cent column. The major third and minor third deviate most, which is why equal-temperament thirds sound slightly beaty compared with pure ones. FAQ: Q: What is the difference between equal temperament and just intonation? A: Just intonation tunes intervals to simple whole-number frequency ratios such as 3:2 for a perfect fifth, which sound pure and beatless. Equal temperament divides the octave into twelve identical steps so music can be played in any key, at the cost of detuning most intervals slightly. Q: What is a cent? A: A cent is one hundredth of an equal-temperament semitone, so an octave contains 1200 cents. It is a logarithmic unit, meaning equal cent differences sound like equal pitch steps regardless of the absolute frequency. Around 5 cents is the threshold most listeners can detect. Q: Which interval is most out of tune in equal temperament? A: The major third is the worst, sitting about 14 cents sharp of the pure 5:4 ratio. The minor third is about 16 cents flat of 6:5. These tempered thirds are why barbershop and a cappella singers, who tune by ear, sound purer than a piano. Q: Why is the perfect fifth almost perfect in equal temperament? A: The equal-temperament fifth is only about 2 cents narrower than the pure 3:2 ratio, far below the audible threshold. That tiny error is why fifths and octaves on a piano sound clean while thirds sound slightly rough. Q: How is the equal-temperament frequency computed? A: Each semitone multiplies the frequency by the twelfth root of two, about 1.059463. So the frequency n semitones above the root equals root times two to the power n divided by twelve. Just-intonation frequencies instead multiply the root by a small whole-number ratio. #### Guitar Fret Spacing Calculator URL: https://geratools.com/fret-spacing-calculator Generate precise fret-slot positions from the nut to the 24th fret for any guitar scale length using the equal-temperament constant 17.817. Built for luthiers, kit builders, and 3D-printed instrument makers. Works in inches or millimetres, 100% in your browser. How to use: 1. Enter your scale length: Type the distance from nut to saddle, e.g. 25.5 in for a Stratocaster or 24.75 in for a Les Paul. 2. Pick the unit and fret count: Choose inches or millimetres and how many frets your neck has, typically 20 to 24. 3. Read the slot positions: The table lists each fret's distance from the nut, the gap from the previous fret, and the remaining length to the bridge. FAQ: Q: What is the rule of 18 for frets? A: The rule of 18 says the nut-to-first-fret distance equals the scale length divided by about 18, and you repeat the division on the remaining length for each fret. The precise constant is 17.817, which equals 1 ÷ (1 − 2^(−1/12)). Q: Why does the 12th fret fall at the halfway point? A: The 12th fret is one octave above the open string, and an octave halves the vibrating length. So the 12th fret always sits at exactly half the scale length — a quick sanity check for any layout. Q: What formula does the calculator use? A: It uses the exact equal-temperament formula: distance from nut to fret n = scale − scale ÷ 2^(n/12). This matches the rule-of-18 result and is what CNC and laser fret-slotting jigs expect. Q: Do I need to add intonation compensation? A: These positions are the theoretical fret centres. Real strings sharpen slightly when fretted, so builders add a small amount of compensation at the saddle (and sometimes the nut). The fret slots themselves stay at the calculated positions. Q: Can I use this for a multi-scale or fanned-fret neck? A: Run the calculator twice, once for the treble-side scale length and once for the bass-side scale length, then connect the matching fret positions to lay out the fan. Each side uses the same formula. #### Harmonic Series Calculator URL: https://geratools.com/harmonic-series-calculator List the frequencies of the first 16 harmonics above any fundamental, showing each overtone's exact frequency, its nearest equal-temperament note, and the cents deviation. A reference tool for additive synthesis, acoustic design, and understanding timbre. How to use: 1. Enter the fundamental: Type the fundamental frequency in hertz, or pick a note to fill it in. This is the first harmonic. 2. Read the overtones: The table lists harmonics 1 through 16 with each exact frequency as an integer multiple of the fundamental. 3. Compare to equal temperament: Each harmonic shows its nearest piano note and how many cents sharp or flat it sits versus equal temperament. FAQ: Q: What is the harmonic series? A: The harmonic series is the set of frequencies that are whole-number multiples of a fundamental. If the fundamental is 100 Hz the harmonics are 200, 300, 400 Hz and so on. Almost every pitched acoustic sound is a blend of these overtones, and their relative loudness defines its timbre. Q: How do I calculate the nth harmonic? A: The nth harmonic frequency is simply the fundamental times n. The 5th harmonic of 220 Hz is 220 times 5, which is 1100 Hz. The fundamental itself is the 1st harmonic. Q: Why do some harmonics not line up with piano notes? A: Equal temperament divides the octave into 12 equal steps, but the harmonic series follows pure whole-number ratios. The 7th and 11th harmonics in particular fall well between piano keys, the 7th about 31 cents flat and the 11th about 49 cents sharp of the nearest equal-tempered note. Q: What is a cent? A: A cent is one hundredth of an equal-tempered semitone, so 1200 cents make an octave. Cents measure how far a frequency sits from a reference pitch. Differences under about 5 cents are hard to hear; differences over 20 cents are clearly out of tune. Q: How does the harmonic series relate to musical intervals? A: The early harmonics spell out familiar intervals: harmonic 2 is an octave above the fundamental, harmonic 3 a perfect twelfth (octave plus fifth), harmonic 5 a major third two octaves up, and so on. Just intonation builds scales directly from these pure ratios. #### Reverb Room Size to Pre-Delay Calculator URL: https://geratools.com/reverb-room-size-pre-delay Compute physically plausible reverb pre-delay in milliseconds from room dimensions and listener position using the real speed of sound. Set natural, realistic pre-delay times in your reverb plugin instead of guessing, and keep vocals clear and present. How to use: 1. Set the room dimensions: Enter the room length and width in metres, or pick a preset like vocal booth, studio, or concert hall. 2. Set the listener position: Enter how far the listener and the nearest reflecting wall are from the source. The tool finds the first reflection path. 3. Read the pre-delay: The calculated pre-delay in milliseconds is the gap before the first reflection arrives. Type it into your reverb plugin. FAQ: Q: What is reverb pre-delay? A: Pre-delay is the silent gap between the direct sound and the start of the reverb tail. In a real room it is the time for the first reflection to travel from the source to a wall and back to the listener. Adding pre-delay keeps the dry signal clear and pushes the reverb behind it. Q: How is pre-delay calculated from room size? A: Sound travels at about 343 metres per second in air at 20 Celsius. The pre-delay is the extra distance a reflected ray travels compared with the direct sound, divided by the speed of sound, times 1000 for milliseconds. A reflection path 5 metres longer than the direct path gives about 14.6 ms of pre-delay. Q: Why does pre-delay make vocals clearer? A: Without pre-delay the reverb starts the instant the voice does and smears the words. A 20 to 40 ms pre-delay separates the dry vocal from the wash of reflections, so the listener hears the words first and the space afterwards. It is one of the most effective tricks for a present, intelligible lead vocal. Q: Does temperature change the result? A: Yes, slightly. The speed of sound rises about 0.6 metres per second for each degree Celsius, so a warm room shortens pre-delay a touch. The tool lets you set temperature, but for mixing the difference between 15 and 25 Celsius is only a fraction of a millisecond and rarely matters. Q: How does pre-delay relate to reverb decay time? A: Pre-delay sets where the reverb starts; decay (RT60) sets how long it lasts. They are independent. A large hall reverb often pairs a longer decay with a moderate pre-delay, while a tight room uses short values for both. Matching pre-delay to a plausible room size keeps the two consistent. #### Scale & Chord Builder URL: https://geratools.com/scale-chord-builder Build the exact note list for any scale (major, natural/harmonic/melodic minor, all seven modes, pentatonic, blues, whole-tone) or chord voicing (triads, 7ths, 9ths, sus, dim, aug) in any root key, shown on an ASCII piano keyboard. How to use: 1. Pick scale or chord: Choose whether you want the notes of a scale or the notes of a chord using the mode selector. 2. Choose the root and type: Select the root note (C, F#, Bb, etc.) and the scale or chord quality (e.g. Dorian, Minor 7th). 3. Read the notes: The note list appears instantly and the matching keys light up on the on-screen keyboard. FAQ: Q: How are the scale notes worked out? A: Each scale is an interval pattern measured in semitones from the root. The major scale, for example, is 0-2-4-5-7-9-11 semitones. The tool adds those intervals to the root pitch class and converts each result back to a note name. Q: Why does it sometimes show flats and sometimes sharps? A: Note spelling follows the key signature convention. Flat keys (F, Bb, Eb, Ab, Db) and any flat root spell their accidentals as flats; sharp and natural keys use sharps. This matches how the notes would appear on a staff. Q: What chord types are supported? A: Triads (major, minor, diminished, augmented, sus2, sus4), sixths, all four 7th qualities, m7b5, dim7, add9, and major/dominant 9ths. Each is an interval set applied to the root, so any chord works in any key. Q: Is the harmonic minor different from natural minor? A: Yes. Natural minor is 0-2-3-5-7-8-10. Harmonic minor raises the 7th to give a leading tone (0-2-3-5-7-8-11). Melodic minor (ascending) raises both the 6th and 7th (0-2-3-5-7-9-11). Q: Does the keyboard show the actual playable notes? A: It shows one octave and highlights every pitch class in the scale or chord. A real performance would span multiple octaves, but the highlighted keys tell you exactly which notes belong to the set. #### Semitone & Cents Interval Calculator URL: https://geratools.com/semitone-cents-calculator Converts between frequency ratios, semitone counts and cent values for any two pitches in equal temperament. Useful for tuning analysis, microtonality, pitch-shift planning, and understanding interval relationships in audio production. Runs 100% in your browser. How to use: 1. Enter the two frequencies: Type the lower and higher pitch in hertz, for example 440 and 660. The tool measures the interval between them. 2. Read the interval in cents and semitones: The tool reports the frequency ratio, the number of equal-tempered semitones, and the precise cent value, along with the nearest named interval. 3. Use it for tuning or pitch shifting: Apply the cent value to detune an oscillator, plan a pitch-shift amount, or check how far a recorded note drifts from concert pitch. FAQ: Q: What is a cent in music? A: A cent is one hundredth of an equal-tempered semitone, so there are 1200 cents in an octave. Cents give a fine-grained, perceptually even way to measure tuning differences that would be clumsy to express as raw hertz. Q: How do you convert a frequency ratio to cents? A: The formula is cents = 1200 x log2(f2 / f1). A perfect octave (ratio 2) is exactly 1200 cents, a perfect fifth in just intonation (ratio 3/2) is about 702 cents, and an equal-tempered semitone is exactly 100 cents. Q: How many cents are in a semitone? A: Exactly 100 cents in equal temperament. Twelve semitones of 100 cents each make up the 1200-cent octave, which is why a half-step shift equals 100 cents. Q: Why is an equal-tempered fifth not exactly 702 cents? A: Equal temperament divides the octave into 12 identical steps, making the fifth exactly 700 cents. The pure just fifth (3/2 ratio) is about 702 cents, so the equal-tempered fifth is roughly 2 cents flat — a tiny, usually imperceptible compromise. Q: Can I use this for microtonal tuning? A: Yes. Enter any two frequencies and the tool reports the exact cent interval, which is the standard unit for describing microtonal and non-Western tunings that fall between the usual 12 semitones. #### Song Key Transposer URL: https://geratools.com/song-key-transposer Shifts a song's key by any number of semitones, showing the new key signature and transposing a whole chord chart of major, minor, 7th, and slash chords to their equivalents in the new key. Ideal for changing keys to suit a singer. Runs 100% in your browser. How to use: 1. Paste your chords: Type or paste a line of chords such as C Am F G or a full chord chart. The tool reads chord names including minor, 7th, sus, and slash chords. 2. Choose how far to shift: Set the number of semitones to move up or down. Plus values raise the key, minus values lower it. The tool also shows the resulting key if you started in a major key. 3. Copy the transposed chords: The tool rewrites every chord into the new key, keeping qualities and bass notes intact, ready to copy back into your chart. FAQ: Q: How does transposing chords work? A: Every chord root is a note on the 12-semitone chromatic scale. Transposing shifts each root by the same number of semitones while keeping the chord quality such as minor or 7th unchanged, so the harmonic relationships stay identical in the new key. Q: Will this transpose minor and 7th chords correctly? A: Yes. The tool separates each chord's root note from its quality suffix, shifts only the root, then reattaches the suffix. So Am7 moved up two semitones becomes Bm7, and Dsus4 becomes Esus4. Q: Does it handle slash chords like C/G? A: Yes. Both the chord root and the bass note after the slash are transposed by the same amount, so C/G moved up two semitones becomes D/A, preserving the inversion. Q: Should I use sharps or flats in the result? A: The tool offers a sharp or flat preference for the accidental notes. Sharps suit keys like D and A, while flats read more naturally in keys like F and B flat. Pick whichever matches your chart. Q: How many semitones is a capo position? A: Each guitar capo fret raises the pitch by one semitone. So a capo on fret 2 transposes everything up two semitones, which is the same as entering plus two here to see the sounding chords. #### Guitar String Tension Calculator URL: https://geratools.com/string-tension-calculator Computes individual guitar string tension in pounds and kilograms from string gauge, scale length, and target pitch using the standard unit-weight tension formula. Helps players optimise playability and tone across alternate tunings. How to use: 1. Enter the string gauge: Type the string diameter in inches (e.g. 0.010) or pick a common gauge. This sets the unit weight used in the formula. 2. Set scale length and pitch: Enter the scale length in inches (25.5 for a Strat, 24.75 for a Les Paul) and choose the target note the string is tuned to. 3. Read the tension: The tool shows tension in pounds and kilograms, plus the fundamental frequency. Aim for roughly 13-18 lb per string for balanced feel. FAQ: Q: What formula is used to calculate string tension? A: Tension equals (unit weight times (2 times scale length in inches times frequency)^2) divided by 386.4. The 386.4 constant is gravitational acceleration in inches per second squared, which converts the result into pounds-force. Q: How is unit weight related to string gauge? A: Unit weight is the mass per inch of the string. This tool estimates it from the wire diameter and steel density, but real wound strings differ slightly because of the core-to-wrap ratio. For exact figures use the manufacturer's published unit-weight tables. Q: Why does scale length change tension? A: A longer scale length needs more tension to reach the same pitch because tension rises with the square of the vibrating length. That is why a baritone at 27 inches feels tighter than a 25.5-inch guitar at the same tuning. Q: What tension feels comfortable to play? A: Most factory sets land between 13 and 18 lb per string, giving a total around 100-110 lb across six strings. Lower tension bends easily but can feel floppy in drop tunings; higher tension gives more attack and tuning stability. Q: Does this work for bass strings? A: Yes, the physics is identical. Enter a longer scale (34 inches is standard for a 4-string bass), the heavier gauge, and the lower target pitch such as E1. Bass strings are wound, so treat the result as an estimate. #### Studio Monitor Placement Calculator URL: https://geratools.com/studio-monitor-placement Calculates optimal studio monitor placement: equilateral-triangle listening distance, 30° toe-in angle, the 38% listening position from the front wall, and speaker distances from front and side walls, all from your room dimensions and chosen separation. How to use: 1. Enter your room dimensions: Type the room length (front to back) and width (side to side) in metres. The calculator places the listening position along the front-to-back axis. 2. Choose monitor separation: Set the tweeter-to-tweeter spacing you want, typically 1.2–1.8 m for nearfields. The tool sets the listening distance equal to this for an equilateral triangle. 3. Read the placement: The calculator returns listening distance, 30° toe-in, the 38% listening spot, and how far each monitor should sit from the front and side walls, with warnings if anything is too close. FAQ: Q: What is the equilateral triangle rule for monitors? A: Place the two monitors and your head at the corners of an equilateral triangle, so the distance between the two tweeters equals the distance from each monitor to your ears. Each monitor is angled 30° inward (toe-in) so it points directly at the listening position, giving a stable, centred stereo image. Q: How much should I toe-in my monitors? A: For an equilateral setup each monitor toes in 30° from straight ahead, aiming directly at the listener. This puts you on-axis where the frequency response is flattest and narrows the sweet spot. Some engineers reduce toe-in slightly to widen the image; experiment, but 30° is the standard starting point. Q: What is the 38% rule? A: The 38% rule places the listening position about 38% of the room length back from the front wall. At that point the listener tends to avoid the worst pressure peaks of the room's length-wise axial modes, giving smoother bass. It is a starting guideline, not an absolute — fine-tune by ear and with measurement. Q: How far should monitors be from the walls? A: Keep monitors away from the front and side walls — at least roughly half a metre where the room allows — to reduce boundary reinforcement and speaker-boundary interference (SBIR) that causes bass dips. Avoid placing a monitor the same distance from the front wall as from the side wall, which stacks reflections at similar frequencies. Q: Should monitors fire down the long or short wall? A: Firing down the longer dimension of the room generally gives more even bass and pushes the strongest front-to-back reflection further away, but it costs floor space. If the room is wide, firing across the short dimension can work with careful side-wall treatment. The calculator uses your stated length as the firing axis. #### Ported Subwoofer Box Volume & Port Calculator URL: https://geratools.com/subwoofer-box-ported Free ported subwoofer box calculator. Enter net enclosure volume, target tuning frequency and port diameter to get the exact port length using the Helmholtz resonator formula with end correction. Runs in your browser. How to use: 1. Enter your net enclosure volume: Type the net internal volume of the box in litres — the air volume after subtracting the driver, bracing and port displacement. 2. Set the target tuning frequency: Enter the desired box resonance (Fb) in Hz. Lower values give deeper, looser bass; higher values raise output near the tuning point. 3. Choose the port size and read the length: Pick the port diameter and number of ports. The calculator returns the required port length and total port area instantly. FAQ: Q: What is the tuning frequency (Fb) of a ported box? A: Fb is the resonant frequency of the Helmholtz system formed by the box air volume and the port. At Fb the port air mass moves in phase with the cone, boosting output and reducing cone excursion. Below Fb the port unloads the driver, so it is the practical low-frequency limit of the enclosure. Q: How do I choose the right tuning frequency? A: Match Fb to the driver Thiele-Small parameters and your goal. A common starting point is to tune near the driver Fs or a few Hz below for music, or lower (28–32 Hz) for deep home-theatre extension. Always run a box-simulation against the driver before cutting wood. Q: Why is my calculated port length so long? A: Small box volume, low tuning, or a large port diameter all increase the required length. If the port will not physically fit, increase the diameter slightly (which raises area and shortens length only modestly) or accept a higher tuning frequency. A larger diameter also reduces port air velocity and chuffing. Q: What is the end correction in the formula? A: Air just outside each port opening also oscillates, effectively lengthening the tube acoustically. The end-correction term subtracts that extra acoustic length so the physical tube you cut produces the correct tuning. This calculator assumes one flush-mounted (flanged) end and one free end, a factor of 1.463 times the port radius. Q: How big should the port area be? A: Port area controls air velocity. Too small a port chuffs (audible turbulence) at high output. A rough guide is at least 12–16 cm² of port area per 100 W, or sizing for a peak velocity under about 5 percent of the speed of sound. Using multiple ports or a larger diameter lowers velocity at the cost of a longer tube. #### Tempo-to-Note-Grid Reference Table URL: https://geratools.com/tempo-to-note-grid Generate a complete reference table of note durations in milliseconds for any BPM, from whole notes down to 64th notes, including dotted and triplet variants. Perfect for setting delay, reverb, and LFO times in your DAW. Includes Hz frequency for each subdivision. How to use: 1. Enter the tempo: Type your track's tempo in beats per minute. The table recalculates instantly for every note value. 2. Read the grid: Each row is a note value (whole through 64th) with columns for straight, dotted, and triplet durations in milliseconds. 3. Dial in your effect: Copy the millisecond value for the subdivision you want into your delay, reverb pre-delay, or LFO rate control. FAQ: Q: How is note duration calculated from BPM? A: One quarter note lasts 60000 divided by BPM milliseconds, because there are 60000 ms in a minute and BPM quarter-note beats per minute. A whole note is four times that, an eighth note is half, a sixteenth note a quarter, and so on by powers of two. Q: What is a dotted note duration? A: A dot adds half the note's value, so a dotted note is 1.5 times the straight duration. Dotted eighth-note delays are a staple of guitar and synth music because they create a rhythmic offset against the straight beat. Q: What is a triplet note duration? A: A triplet fits three notes into the space of two, so a triplet duration is two thirds (0.6667) of the straight value. Triplet delays give a rolling, swung feel that locks to the beat differently from straight or dotted timing. Q: Should I use note duration for delay feedback or just the delay time? A: Set the delay time to the millisecond value for the subdivision you want; feedback only controls how many repeats you hear, not their spacing. For tempo-synced delays many DAWs let you enter note values directly, but the ms figure is essential for hardware units and plugins without sync. Q: How do I convert a note duration to an LFO frequency in Hz? A: Frequency in Hz equals 1000 divided by the duration in milliseconds. A one-bar LFO at 120 BPM lasts 2000 ms, which is 0.5 Hz. The table shows the Hz value alongside each millisecond figure so you can set free-running LFOs to the beat. #### BPM to Milliseconds Calculator URL: https://geratools.com/bpm-to-milliseconds Convert BPM to milliseconds for delay, reverb pre-delay and tempo-synced effects. Shows straight, dotted and triplet times for every note value, plus Hz. Runs entirely in your browser. How to use: 1. Enter your tempo: Type the track tempo in beats per minute (BPM). 2. Read the table: Each note value shows its length in milliseconds for straight, dotted and triplet feels. 3. Dial in your effect: Copy the millisecond value into your delay, reverb pre-delay or LFO sync setting. FAQ: Q: How do you convert BPM to milliseconds? A: One quarter-note beat equals 60000 divided by the BPM. At 120 BPM that is 60000 / 120 = 500 ms. Other note values scale from that beat: a half note is double, an eighth is half, a sixteenth is a quarter, and so on. Q: What is the delay time for 120 BPM? A: A quarter note at 120 BPM is 500 ms, an eighth note is 250 ms and a sixteenth is 125 ms. Use those as your delay times to lock the echoes to the beat. Q: What are dotted and triplet times? A: A dotted note lasts 1.5 times the straight value, giving a galloping feel popular for delays. A triplet lasts two-thirds of the straight value, fitting three notes in the space of two. Q: What is the Hz column for? A: It is the rate of the note value in cycles per second (1000 ÷ milliseconds). It is handy for setting tempo-synced LFOs or tremolo by frequency instead of by time. Q: Which note values are shown? A: Whole, half, quarter, eighth, sixteenth and thirty-second notes, each with straight, dotted and triplet timings, all derived from the quarter-note beat. Q: Should I use the dotted-eighth delay trick? A: It is a classic effect: a dotted-eighth delay (1.5 × the eighth-note time) creates a syncopated, rhythmic echo. Read the dotted column next to the eighth-note row to get the exact ms value. Q: Is anything sent to a server? A: No — every calculation runs locally in your browser. #### Note Frequency Calculator URL: https://geratools.com/note-frequency-calculator Calculate the frequency in hertz of any musical note and octave using equal temperament and an adjustable A4 reference. Shows the MIDI number and wavelength too. Runs entirely in your browser. How to use: 1. Choose a note and octave: Pick the note name and type the octave number (A4 is concert A). 2. Set the reference pitch: Keep A4 at the standard 440 Hz or change it to match your tuning. 3. Read the frequency: The exact frequency in hertz appears, along with the MIDI number and wavelength. FAQ: Q: How is a note frequency calculated? A: Equal temperament uses f = ref × 2^((n − 69) / 12), where n is the MIDI note number and ref is the A4 reference. With A4 = 440 Hz and MIDI 69, every other note is a fixed ratio away. Q: Why can I change the A4 reference? A: Concert pitch is usually 440 Hz, but many orchestras tune to 441–443 Hz and historical or baroque tuning uses 415 Hz. Adjusting the reference recalculates every note to match. Q: What is the MIDI note number? A: The MIDI note number is a standard integer for each pitch: A4 is 69, middle C (C4) is 60, and each semitone up or down changes the number by one. The calculator shows it alongside the frequency. Q: How is the wavelength calculated? A: The wavelength is the speed of sound in air divided by the frequency. The tool uses 343 m/s (air at about 20°C), so wavelength = 343 ÷ frequency in metres. Q: What frequency is A4 at standard concert pitch? A: A4 is 440 Hz at standard concert pitch, which is the default reference. This is the anchor from which every other note is calculated. Q: Is my input uploaded anywhere? A: No — the calculation happens entirely in your browser. #### Music Interval Calculator URL: https://geratools.com/music-interval-calculator Calculate the frequency of any musical interval from a base pitch, with equal-temperament ratios, cents and a reference table of interval names and just ratios. Runs entirely in your browser. How to use: 1. Enter a base frequency: Type the starting pitch in hertz, such as 440 for concert A. 2. Set the interval: Enter the number of semitones to move; use a negative number to go down. 3. Read the result: The target frequency, ratio, cents and interval name appear instantly. FAQ: Q: How do you find the frequency of an interval? A: In equal temperament the frequency ratio for an interval is 2^(semitones / 12). Multiply the base frequency by that ratio: a perfect fifth (7 semitones) gives 440 × 2^(7/12) ≈ 659.26 Hz. Q: What is a cent? A: A cent is one hundredth of an equal-tempered semitone, so an octave is 1200 cents. Cents make tiny tuning differences easy to compare between systems. Q: What is the difference between equal-temperament and just ratios? A: Equal temperament divides the octave into 12 identical steps so any key sounds the same. Just ratios use small whole-number fractions (like 3:2 for a fifth) that sound purer but are key-dependent. Q: What note is a perfect fifth above A 440? A: A perfect fifth is 7 semitones. 440 × 2^(7/12) ≈ 659.26 Hz, which is the note E5. Q: How many cents is a semitone? A: Exactly 100 cents in equal temperament, so a whole tone is 200 cents and a full octave is 1200 cents. Q: How do I transpose a note down? A: Enter a negative number of semitones. For example, -12 drops the pitch by an octave, halving the frequency (440 Hz becomes 220 Hz). #### Speaker Impedance Calculator URL: https://geratools.com/speaker-impedance-calculator Free speaker impedance calculator. Instantly find the combined load for any series, parallel or mixed wiring topology, check amplifier safety, and see how power splits across drivers. 100% client-side — no data uploaded. How to use: 1. Enter your amplifier minimum impedance: Check your amp manual for the minimum speaker load — usually 4 Ω for solid-state, 4–16 Ω for valve amps. 2. Set the wiring mode for each speaker group: Choose series (impedances add) or parallel (reciprocals add) per group. Click the quick-select buttons for standard 4 Ω, 8 Ω or 16 Ω drivers. 3. Add a second group if needed: Use the top-level wiring control to combine multiple groups in series or parallel for complex cabinets. 4. Read the total impedance and power split: The large coloured figure shows the combined load. The power-distribution table shows how each driver shares the amplifier output. FAQ: Q: What is speaker impedance? A: Impedance is the total opposition a speaker presents to AC current — the complex (frequency-dependent) equivalent of resistance. It is measured in ohms (Ω). Most home hi-fi drivers are nominally 4 Ω or 8 Ω; PA and guitar-amp drivers are often 8 Ω or 16 Ω; headphone drivers range from 16 Ω to 600 Ω. Q: How do I calculate the impedance of two 8 Ω speakers in parallel? A: For two identical speakers in parallel the formula simplifies to Z/2, giving 8/2 = 4 Ω. The general parallel formula is 1/Z_total = 1/Z1 + 1/Z2, so for 4 Ω and 8 Ω in parallel: 1/(1/4 + 1/8) = 1/(3/8) = 2.67 Ω. Enter those values here and the calculator shows the same result instantly. Q: What happens if the total impedance is below my amp minimum? A: A load lower than the rated minimum forces the amplifier to deliver more current than its output stage was designed for. Solid-state amps typically clip or engage protection circuitry; valve amps can overheat output transformers. The calculator flags this in red and marks the result as "Too Low". Q: Why does power handling matter? A: Each driver has a maximum RMS power it can absorb before the voice coil overheats. In a series chain the weakest driver limits the whole system. In a parallel chain each driver handles a fraction of the total power determined by its relative impedance. The power-distribution table makes this visible so you can balance matched or mismatched drivers safely. Q: What is the difference between nominal and minimum impedance? A: Nominal impedance (e.g. "8 Ω") is the rounded catalogue value. Actual impedance varies with frequency — a driver rated 8 Ω may dip to 5–6 Ω at resonance. The IEC 60268-5 standard says the minimum impedance must not fall below 80% of nominal. When designing a system, use the measured minimum impedance (from a Thiele–Small or impedance-sweep plot) for worst-case amplifier-load calculations. Q: Can I mix 4 Ω and 8 Ω speakers? A: Yes. The calculator handles mismatched impedances in any topology. Be aware that in parallel the lower-impedance driver draws more current and receives more power; in series the higher-impedance driver receives more power. The power-distribution table shows the exact split so you can check each driver stays within its rated capacity. #### Capo Transpose Calculator URL: https://geratools.com/capo-transpose-calculator Free capo transpose calculator for guitar. Enter the chord you want to sound and a capo fret: the tool shows which open chord shape to play, plus the sounding root frequency. Works entirely in your browser — nothing is uploaded. How to use: 1. Choose your mode: Select "I want to sound a chord" to find the capo fret and open shape, or "I know my open chord and capo" to find the sounding pitch. 2. Pick the target note and quality: Choose the root note (C through B) and chord quality (major, minor, 7th, etc.) that you want the audience to hear. 3. Set the capo fret: Drag the fret number or type it directly. The calculator instantly shows the open chord shape to play and the sounding root frequency in Hz. 4. Browse all capo options: The "all capo options" table lists frets 1 through 7 so you can pick whichever open shape is easiest to finger. FAQ: Q: How does a guitar capo work? A: A capo clamps across all six strings at a chosen fret, effectively raising the nut. Every open string — and every chord shape played above the capo — sounds higher by one semitone per fret. Placing the capo on fret 2, for example, raises all pitches by a whole tone (two semitones), so a C-shape chord sounds like a D. Q: What is the transpose formula used here? A: Two mirror formulas cover both directions. To find what open shape to play: open_root = (sounding_root - capo_fret) mod 12. To find what a shape sounds like: sounding_root = (open_root + capo_fret) mod 12. Both use modular arithmetic on the chromatic scale (12 notes per octave), which is why the result "wraps around" from B back to C. Q: How is the root frequency calculated? A: The tool uses the standard equal-temperament formula f = 440 x 2^((n - 69) / 12), where n is the MIDI note number and A4 = 69. Middle C (C4) is MIDI 60, so a D4 root (two semitones above C4) gives n = 62 and f = 440 x 2^((62-69)/12) = approximately 293.66 Hz. Q: Does the capo change the chord quality (major, minor)? A: No. A capo transposes pitch only — it shifts every note up by the same number of semitones, preserving all intervals within the chord. A minor shape played above the capo still sounds as a minor chord; only the root note name changes. Q: Which capo fret gives the easiest shapes? A: Capo frets 1 through 5 are most common because they keep the chord shapes in the open-position zone (C, D, E, G, A, Am, Em, etc.). The "all capo options" table in the calculator highlights the open-shape hint for each fret so you can spot at a glance which position lets you use a familiar fingering. Q: Can this calculator handle flat keys? A: Yes. Toggle "Show flat spellings" and every note is displayed in flat notation (Bb, Eb, Ab, Db, Gb) instead of sharps. The underlying chromatic arithmetic is identical — only the display label changes. #### Cents to Frequency Calculator URL: https://geratools.com/cents-to-frequency-calculator Free cents-to-frequency calculator. Enter a base frequency and a cent offset to find the target pitch, reverse any two frequencies into cents, or look up any MIDI note. Uses the exact formula f2 = f1 x 2^(cents/1200). 100% browser-side. How to use: 1. Choose a mode: Pick "Cents to Frequency" to find the target pitch, "Frequency to Cents" to measure an interval, or "MIDI note to Frequency" to look up any MIDI note. 2. Enter your base frequency or MIDI note: Type the starting frequency in Hz (e.g. 440 for A4) or the MIDI note number (0-127). The A4 reference defaults to 440 Hz but you can change it for historical or alternative tunings. 3. Enter the cent offset: Type the number of cents you want to move — positive goes up, negative goes down. 100 cents = 1 semitone, 1200 cents = 1 octave. 4. Read the result: The calculator shows the exact output frequency, the frequency ratio, the nearest note name with deviation in cents, and a quick-reference table covering the full octave. FAQ: Q: What is a cent in music? A: A cent is 1/100th of a semitone in equal temperament, making it 1/1200th of an octave. The word comes from the Latin centum (one hundred). Because human pitch perception is roughly logarithmic, cents provide a perceptually linear unit: moving 10 cents always sounds like the same tiny interval regardless of register. Q: What is the formula to convert cents to frequency? A: f2 = f1 x 2^(cents / 1200). The ratio 2^(1/1200) is the frequency multiplier for a single cent. To reverse it: cents = 1200 x log2(f2 / f1). Both formulas follow from the equal-temperament definition where the octave (factor of 2) is divided into 1200 equal logarithmic steps. Q: How many cents is a semitone, a tone, and an octave? A: One semitone = 100 cents. One whole tone (major second) = 200 cents. A perfect fifth = 700 cents. An octave = 1200 cents. These are equal-temperament values; just-intonation intervals differ by a few cents (e.g. a just perfect fifth is 701.96 cents, about 2 cents wider than equal temperament). Q: How accurate are cents for measuring tuning deviation? A: Very accurate for practical purposes. Most trained listeners can detect deviations of 5-10 cents; professional orchestral tuning tolerates roughly plus or minus 5 cents. Electronic tuners typically resolve to 1 cent, which corresponds to a frequency change of about 0.058% — for A4 (440 Hz) that is approximately 0.25 Hz per cent. Q: What is the A4 reference frequency and why does it matter? A: A4 is the note A in the fourth octave (MIDI 69), used as the universal tuning reference. Modern concert pitch is standardised at 440 Hz (ISO 16 / 1975). Earlier periods used different references: Baroque ensembles often tuned to 415 Hz (a semitone lower), some orchestras use 441-443 Hz for a brighter sound, and historically documented pitches range from about 380 Hz to 465 Hz. Changing the A4 reference shifts every calculated frequency proportionally. Q: How do I convert a MIDI note number to a frequency? A: Use the formula f = A4 x 2^((n - 69) / 12) where n is the MIDI note number and A4 is your tuning reference (default 440 Hz). MIDI note 69 = A4, MIDI 60 = middle C (C4), MIDI 0 = C-1 at about 8.18 Hz, and MIDI 127 = G9 at about 12 544 Hz. #### Chord Finder URL: https://geratools.com/chord-finder Free interactive chord finder: select a root note and chord type to see every note, interval name, and frequency — or click piano keys to reverse-identify any chord. Plays audio in your browser. Covers triads, seventh, extended, and more. How to use: 1. Choose your mode: Select "Build a Chord" to pick a root note and chord type, or "Identify a Chord" to click notes and find what chord they form. 2. Select a root note: In Build mode, click any note button (C through B) or click a white piano key to set the root. The highlighted keys update instantly. 3. Pick a chord type and category: Filter by Triads, Seventh, Sixth, Extended, or Other, then click the chord name you want. The formula, intervals, and Hz frequencies all update immediately. 4. Play and copy: Press Play to hear the chord through your browser. Toggle Arpeggio to strum the notes in sequence. Copy pastes the chord name and notes to your clipboard. 5. Identify a chord: Switch to Identify mode, click 2 to 7 piano keys or note buttons, and the tool lists every matching chord name from its library of 24 chord types. FAQ: Q: How does the chord finder know which notes belong to a chord? A: Every chord type is defined as a set of semitone offsets from the root. A major chord is [0, 4, 7] (root, major 3rd, perfect 5th). The tool adds each offset to the root note index modulo 12 to wrap around the octave, giving the exact pitch class for each chord member. Q: What is the formula for note frequency? A: The standard equal-temperament formula is f = 440 × 2^((n − 69) / 12), where n is the MIDI note number. For example, middle C (C4) is MIDI 60, giving 440 × 2^(−9/12) ≈ 261.6 Hz. Each semitone step multiplies the frequency by the 12th root of 2 (≈1.0595). Q: What chord types are included? A: The tool covers 24 chord types across six categories — Triads (major, minor, diminished, augmented, sus2, sus4), Seventh chords (dominant 7, major 7, minor 7, half-diminished, diminished 7, and more), Sixth chords, Extended chords (9th, 11th, 13th, add9), and Power chords. Enharmonic notes (C# = Db, F# = Gb, etc.) are shown where relevant. Q: Why does Identify mode sometimes find multiple chord names? A: The same set of pitch classes can often be interpreted as more than one chord — for instance, C–E–G–B can be C major 7 (root C) or E minor with added major 7th. This is called enharmonic or reharmonisation ambiguity. The tool lists all valid matches so you can choose the one that fits the harmonic context. Q: What is a semitone and how do intervals work? A: A semitone is the smallest interval in Western equal-temperament tuning — one fret on a guitar, or one adjacent key on a piano. A major 3rd is 4 semitones, a perfect 5th is 7. Chords are built by stacking intervals from a root; a major triad uses intervals [0, 4, 7], while a minor triad uses [0, 3, 7] (flattened 3rd). Q: Can I use this for guitar, piano, or other instruments? A: Yes. The chord finder is instrument-agnostic — it works purely with pitch classes (note names) and frequencies. Once you know the notes in a chord, you can find those pitches on any instrument. The built-in piano keyboard is a visual aid; the note names and intervals apply equally to guitar, bass, ukulele, or any other chromatic instrument. #### Guitar String Tension Calculator URL: https://geratools.com/guitar-string-tension-calculator Free guitar string tension calculator. Enter your scale length, tuning, and string gauges to see the tension on every string and the total load on your neck — or work backwards to find the gauge that delivers a target feel. Supports standard, drop-D, DADGAD, open tunings and more. 100% browser-based. How to use: 1. Choose your scale length: Select a preset (Gibson 24.75", Fender 25.5", PRS 25", baritone 27") or enter a custom value in inches. Scale length is the vibrating string length from nut to saddle. 2. Pick a tuning: Choose from standard, Drop D, half-step down, full-step down, DADGAD, Open G, or Open E. The calculator automatically fills in the correct note and frequency for each string. 3. Enter your string gauges and materials: For each of the six strings type the gauge in inches (e.g. 0.010) and select the winding material — plain steel, nickel wound, phosphor bronze, or nylon. Unit weights are sourced from published D'Addario string tension data. 4. Read the tension per string and total: Each string shows its frequency and tension in pounds, kilograms, or Newtons. The summary card shows total load on the neck across all six strings. 5. Use gauge-suggestion mode: Switch to "Suggest gauge for target tension", enter your desired tension per string, and the calculator recommends the nearest available gauge in your chosen material. FAQ: Q: What is the guitar string tension formula? A: The standard industry formula is T = UW x (2 x L x f)^2 / 386.089, where T is tension in pounds, UW is the unit weight (mass per unit length in lb/in) of the string, L is the vibrating scale length in inches, and f is the target frequency in Hz. The constant 386.089 is gravitational acceleration in in/s^2. D'Addario, Ernie Ball, and most string manufacturers publish their unit-weight tables; this calculator uses those values. Q: How does scale length affect tension? A: Tension rises with the square of scale length at a fixed pitch. A Fender-scale guitar (25.5") puts significantly more tension on each string than a Gibson-scale (24.75") with identical gauges and tuning. The difference is roughly 6–7%, which is why many players go up half a gauge set when moving to a shorter-scale guitar to keep the same feel. Q: What total tension is safe for a guitar neck? A: Most steel-string acoustic necks are engineered for roughly 150–180 lb of total string tension. Standard electric light sets (.009–.042) on a 25.5" Fender produce around 105–115 lb total. Baritone instruments at 27" with heavy gauges can exceed 160 lb. Always check your luthier or manufacturer guidance before fitting very heavy strings, especially on vintage or lightweight instruments. Q: Why does tuning down reduce string tension? A: Tension is proportional to the square of frequency. Dropping from E2 (82.4 Hz) to D2 (73.4 Hz) on the low string reduces tension by about 21%. This is why drop tunings feel "floppy" with light gauges and why many players compensate by moving up a gauge or two — or switch to a heavier-bottom mixed set. Q: What is unit weight and where does it come from? A: Unit weight (UW) is the mass of one inch of string in pounds. It depends on the wire diameter, the winding type, and the core-to-wrap ratio. Plain strings follow steel density closely, so UW scales nearly as the square of gauge diameter. Wound strings deviate because the winding metal and air gaps change the effective density. The values in this calculator come from published D''Addario string tension specification sheets, which are the most widely cited in the industry. Q: Does changing tuning change the recommended gauge? A: Yes. The gauge-suggestion mode works backwards from the tension formula to find the unit weight that delivers your target tension at the new tuning and scale length. For example, if you drop a half-step to Eb standard, the calculator will suggest slightly heavier gauges to restore the same feel as standard tuning. The suggestion rounds to the nearest gauge in the published table for that material. #### Key Transpose Calculator URL: https://geratools.com/key-transpose-calculator Free key transpose calculator: shift a song from one key to another, transpose a chord chart by any number of semitones, and view the complete diatonic scale and triads for any key or mode. Runs entirely in your browser. How to use: 1. Choose the Key Transposer tab: Select your original key, your target key, and the scale quality (major or minor). The calculator shows every diatonic chord mapped from the original to the transposed key. 2. Transpose a full chord chart: Paste your chord chart — like "C G Am F" or a multi-line verse/chorus sheet — into the Chord Chart tab, enter the number of semitones (positive = up, negative = down), and copy the result. 3. Explore a scale or mode: Open the Scale Builder tab, pick any root note and mode (Major, Dorian, Phrygian, Lydian, Blues, Pentatonic, and more) to see every scale degree and the diatonic triads built on each degree. FAQ: Q: What does transposing a key mean? A: Transposing shifts every note and chord in a piece by the same interval — a fixed number of semitones up or down — so the music sounds the same relative to itself but at a different overall pitch. A song in C major transposed up 7 semitones becomes G major; the I–IV–V–vi chord progression (C–F–G–Am) becomes G–C–D–Em. Q: How is the transposition interval calculated? A: The calculator finds the pitch-class index of both keys (C=0, C#/Db=1 … B=11) and computes (targetPc − sourcePc + 12) mod 12. That gives the number of semitones to add to every chord root. The same offset is applied to every degree of the diatonic scale, preserving each chord quality (major, minor, diminished). Q: Why does the same note have two names — like C# and Db? A: C# and Db are enharmonic equivalents: they represent the same piano key but are spelled differently depending on context. Keys with sharps in their key signature (G, D, A, E, B) conventionally use sharp spellings; keys with flats (F, Bb, Eb, Ab, Db, Gb) use flat spellings. The calculator follows these conventions automatically, and you can override the preference in the Chord Chart tab. Q: Can I transpose by a full octave? A: Yes — entering +12 or −12 semitones moves every chord up or down by one octave. The note names stay identical, only the register changes. This is useful when a song sits too high or too low for a singer and you want to move it by an exact octave without changing the key. Q: How do I use this as a guitar capo calculator? A: A capo on fret N raises every open chord by N semitones. If the original key is G and you want to play open C-shape chords with a capo, transpose from C to G (+7 semitones) to find which chord shapes to use — then place the capo on fret 7. Alternatively, transpose from the original key to C (or whichever open-chord key suits your playing) and use that capo fret. Q: What modes are included in the Scale Builder? A: The Scale Builder covers all seven diatonic modes (Ionian/Major, Dorian, Phrygian, Lydian, Mixolydian, Aeolian/Natural Minor, Locrian), Harmonic Minor, Pentatonic Major, Pentatonic Minor, Blues, Whole Tone, and the Diminished (half-whole) scale — 13 scales in total. For each scale it shows the semitone offsets, interval names, and (for 7-note scales) the full set of diatonic triads. #### Semitone Interval Calculator URL: https://geratools.com/semitone-interval-calculator Free semitone interval calculator. Choose two notes with octave, get the exact semitone count, cents, equal-temperament frequency ratio, both frequencies, the named musical interval and the deviation from just intonation. Runs entirely in your browser. How to use: 1. Select your two notes: Choose the note name (C through B) and octave number for both notes. Use the flats toggle to display Db/Eb/Gb/Ab/Bb instead of sharps. 2. Set the A4 reference pitch: The default is 440 Hz (concert pitch). Change it to 432 Hz, 415 Hz (Baroque), or any other standard if your instrument is tuned differently. 3. Read the semitone and cents result: The tool shows the signed semitone distance (positive = ascending, negative = descending), the equivalent in cents (1 semitone = 100 cents in equal temperament), and the named interval. 4. Compare equal temperament vs just intonation: The 'ET vs Just intonation' card shows how many cents the equal-temperament version deviates from the pure harmonic ratio. Values above 5 cents are noticeable to a trained ear. 5. Expand the formula working: Click 'Show formula working' to see every step of the MIDI lookup and frequency calculation. FAQ: Q: How many semitones are in an octave? A: Exactly 12. In Western 12-tone equal temperament (12-TET) the octave is divided into 12 equal semitones, each 100 cents wide. Two notes an octave apart have a 2:1 frequency ratio. Q: What is a cent in music? A: A cent is 1/100th of a semitone — so one octave = 1,200 cents. Cents give a fine-grained way to describe tuning differences. The human ear can typically detect deviations of about 5-10 cents, and string or wind players regularly adjust by 10-20 cents when tuning to just intonation or historical temperaments. Q: What is the formula for equal-temperament frequency ratio? A: For n semitones, the ratio is 2^(n/12). One semitone = 2^(1/12) ≈ 1.059463. A perfect fifth (7 semitones) = 2^(7/12) ≈ 1.498307. Compare that to the just-intonation pure fifth of 3:2 = 1.5 — a difference of about 1.96 cents. Q: What is just intonation and how does it differ from equal temperament? A: Just intonation uses pure integer frequency ratios derived from the harmonic series (e.g., a perfect fifth is exactly 3:2 = 1.5). Equal temperament compromises by making all semitones identical, so every interval except the octave is slightly mistuned relative to the pure ratio. The biggest deviation is the major third (ET 400 cents vs just 386.31 cents — a 13.69-cent gap that is clearly audible). Orchestras and choirs often bend toward just intonation when playing sustained chords. Q: How do I calculate the frequency of any note? A: The formula is f = A4_ref × 2^((MIDI − 69) / 12). The MIDI number of a note is (octave + 1) × 12 + pitch-class-index, where C = 0, C# = 1, D = 2 … B = 11. For example, middle C (C4) has MIDI 60, so f = 440 × 2^((60−69)/12) = 440 × 2^(−0.75) ≈ 261.63 Hz. Q: What is the tritone and why is it special? A: The tritone is 6 semitones — exactly half an octave. Its equal-temperament ratio is 2^(1/2) ≈ 1.4142, and it divides the octave symmetrically. It sounds maximally ambiguous and tense, which is why medieval theorists called it 'diabolus in musica'. In jazz it is the defining dissonance of a dominant seventh chord, and tritone substitution is a core harmonic technique. #### Time Signature Calculator URL: https://geratools.com/time-signature-calculator Free time signature calculator: find exact beat and bar durations in milliseconds for any time signature and BPM, compare simple vs compound meters, analyse polyrhythms with a coincidence grid, and tap a tempo to measure it live. How to use: 1. Choose a time signature: Pick from the preset list (4/4, 3/4, 6/8, 7/8 and more) or select Custom to enter any numerator and denominator. 2. Enter your BPM: Type the tempo in beats per minute. The beat and bar durations update instantly. 3. Pick an analysis mode: Choose Beat durations for a full timing table, Simple vs Compound for a side-by-side comparison, Polyrhythm to map two independent pulse streams, or Tap tempo to measure a live groove. 4. Read the results: The summary pills show bar duration, effective beats, pulse length and meter type. The table and grid give per-subdivision timing in milliseconds. FAQ: Q: What is a time signature in music? A: A time signature is the pair of numbers written at the start of a piece of music. The top number (numerator) tells you how many beats are in each bar; the bottom number (denominator) tells you which note value counts as one beat. In 4/4 there are 4 quarter-note beats per bar; in 6/8 there are 6 eighth-note beats (though they are normally felt as 2 groups of 3). Q: How do you calculate beat duration in milliseconds? A: One quarter-note beat at a given BPM lasts 60 000 / BPM milliseconds. For a different denominator, scale by 4 / denominator. So at 120 BPM a quarter note lasts 500 ms, an eighth note lasts 250 ms and a dotted quarter (used as the pulse in 6/8) lasts 750 ms. The full formula is: unit_ms = (60 000 / BPM) x (4 / denominator). Q: What is the difference between simple and compound time? A: In simple time (2/4, 3/4, 4/4) each beat divides naturally into two equal halves — giving an even, march-like feel. In compound time (6/8, 9/8, 12/8) the numerator is a multiple of 3 and the natural division is into three equal parts, producing a rolling or swung feel. The denominator unit is the same in both cases; what changes is how those units group into higher-level pulses. Q: How many beats are in a bar of 6/8? A: Technically 6 eighth-note counts, but musicians almost always feel 6/8 as 2 dotted-quarter pulses (compound duple). Each dotted quarter lasts 3 eighth notes. At 120 BPM each eighth note lasts 250 ms, so one dotted-quarter pulse lasts 750 ms and the full bar lasts 1 500 ms. The calculator shows both the 6-unit and 2-pulse views. Q: What is a polyrhythm? A: A polyrhythm overlays two different rhythmic streams across the same span of time. The classic 3-against-2 pattern divides the bar into 3 equally spaced pulses in one voice and 2 in another. The coincidences — the moments both voices land simultaneously — occur at multiples of the bar divided by the LCM of the two pulse counts. The Polyrhythm mode draws a grid so you can see exactly where those landings fall. Q: How do I use tap tempo to find a BPM? A: Switch to Tap tempo mode and tap the large button in time with the music on every beat. After the second tap the tool starts averaging the intervals between taps. It keeps the last 16 taps and resets automatically if you stop for more than 4 seconds. The measured BPM feeds straight into the beat-grid and timing panels so you can immediately see the bar length and subdivision times for the groove you just tapped. #### BPM Delay Calculator URL: https://geratools.com/bpm-delay-calculator A professional BPM delay calculator for producers, engineers and musicians. Convert any tempo to millisecond delay times for all note values (straight, dotted, triplet), reverse-calculate BPM from a known delay time, tap to detect tempo, and see how many echoes a given feedback percentage produces before silence. 100% client-side. How to use: 1. Pick a mode: Choose from BPM to delay times, delay time to BPM, tap tempo, or feedback decay using the Mode selector at the top. 2. Enter your tempo or tap along: Type a BPM in the field, or switch to Tap Tempo and tap the button on every beat to detect the tempo automatically. 3. Read the delay table: Every note value — whole, half, dotted quarter, quarter, triplet, eighth, dotted eighth, eighth triplet, sixteenth, dotted sixteenth, sixteenth triplet and thirty-second — shows its delay time in milliseconds and its equivalent frequency in Hz. 4. Copy a value to your DAW: Click the copy button next to any millisecond value, then paste it into your delay plug-in, hardware unit, or reverb pre-delay field. 5. Reverse-engineer a tempo: Switch to Delay time to BPM, enter the known millisecond value, select which note value that time represents, and the tool calculates the matching BPM. 6. Model feedback and echo decay: Switch to Feedback decay, set a feedback percentage and a silence threshold in dB, and expand the echo table to see the exact timing and level of every repeat until it disappears into the noise floor. FAQ: Q: How is BPM converted to a delay time in milliseconds? A: The formula is delay (ms) = 60000 divided by BPM, multiplied by the note-value multiplier. A quarter note has a multiplier of 1, so at 120 BPM one quarter-note delay is 60000 / 120 = 500 ms. An eighth note is half that (250 ms). A dotted eighth note is 1.5 times an eighth note (375 ms). A triplet eighth is two-thirds of an eighth note (166.67 ms). Q: What is the famous dotted-eighth delay trick? A: Setting a delay to the dotted-eighth note time creates a syncopated, galloping repeat that sits between the beats. It was popularised by U2 guitarist The Edge. At 120 BPM the dotted-eighth delay is 375 ms. Find that row in the BPM to delay table and press copy, then paste it into your plug-in. Q: How does the tap-tempo detection work? A: Each time you press the TAP button the tool records the timestamp to within a millisecond using the browser performance timer. It keeps the most recent 8 tap intervals, averages them, and divides 60000 by the average to get the BPM. A gap of more than 3 seconds resets the session so you can start fresh. Q: What does the Hz column mean? A: The Hz value is the reciprocal of the delay time (1000 divided by the milliseconds). It tells you the rate of that note value in cycles per second, which is useful when setting tempo-synced LFO rates on synthesisers or tremolo effects that accept frequency rather than time. Q: How does the feedback decay table work? A: After the original signal plays, the delay unit feeds a percentage of the output back into the input. After n echoes the amplitude is feedback raised to the power n. For example, at 60% feedback the first echo is 60% of the original, the second is 36%, the third 21.6%, and so on. The tool solves for how many repeats occur before the amplitude drops below the dB threshold you set, typically -60 dB (one-millionth of the original). Q: How do I reverse-engineer a tempo from a delay time on old hardware? A: Switch to the Delay time to BPM mode, enter the millisecond value shown on the hardware, and select which note value that time is supposed to represent. The tool calculates the matching BPM so you can set your DAW or drum machine to the same tempo and lock everything to the grid. Q: Is this tool accurate enough for professional use? A: Yes. All arithmetic is done in double-precision floating point and results are rounded to 2 decimal places for display. The core formula (60000 / BPM) is the same one used in DAWs, hardware sequencers and every professional delay calculator. Results match industry-standard references such as the tables printed in tape-delay manuals and modern DAW sync utilities. #### Metronome & BPM Tapper URL: https://geratools.com/metronome-bpm-tapper Free online metronome with tap-tempo detection. Tap or press Spacebar to measure BPM, then run a Web Audio click-track in any time signature. See exact delay times for every note value (straight, dotted, triplet) in milliseconds and Hz — ideal for music producers, drummers and guitarists. How to use: 1. Tap or press Spacebar to detect your tempo: Click the TAP button (or hit Spacebar) repeatedly in time with any music. After two taps the calculator shows the average BPM; after four or more taps the reading stabilises. The window resets automatically after 2.5 seconds of silence. 2. Fine-tune the BPM with the slider or number field: Drag the slider or type an exact value between 20 and 300 BPM. Use the Half-tempo and Double-tempo buttons to shift by an octave. 3. Choose a time signature: Select 4/4, 3/4, 2/4, 6/8, 5/4 or 7/8 from the dropdown. The beat-indicator circles update to show the correct number of pulses per bar, with the downbeat (beat 1) lit in green. 4. Start the click-track: Press Start to hear an accented downbeat click and softer sub-beat clicks via your browser Web Audio engine. No plugins required. Press Stop at any time. 5. Read the note-delay table: The table below the metronome shows straight, dotted and triplet delay times in milliseconds for every note value from whole notes to 32nd notes, plus the equivalent Hz. Click any cell to copy the value to your clipboard for pasting into a DAW delay plug-in. FAQ: Q: How is tap tempo calculated? A: Each tap is timestamped with performance.now() for sub-millisecond accuracy. The average inter-tap interval is computed as (last_tap - first_tap) / (tap_count - 1), then converted to BPM with the formula BPM = 60 000 / interval_ms. Using the average across all taps rather than just the last two intervals smooths out human timing imprecision. Q: What is the formula for note delay times? A: One quarter-note beat lasts 60 000 / BPM milliseconds. All other note values are multiples of that beat: a whole note is 4x, a half note 2x, an eighth 0.5x, a sixteenth 0.25x, a 32nd 0.125x. A dotted note adds half its own value (1.5x), and a triplet note takes two-thirds of the straight value (2/3x). Q: How accurate is the browser metronome? A: This tool uses the Web Audio API lookahead scheduler (25 ms poll, 100 ms schedule-ahead window) rather than setInterval alone. setTimeout/setInterval can drift by 15-100 ms under load; the Web Audio clock is tied to the audio hardware and stays within 1-2 ms. This matches the accuracy of many desktop DAW click-track outputs. Q: What is BPM and how is it used in music production? A: BPM stands for Beats Per Minute — the number of quarter-note pulses in 60 seconds. It is the universal tempo reference: a DAW session grid, a drum machine pattern length, a delay plug-in sync value and a pitch-to-frequency mapping all derive from BPM. Producers set a project BPM first, then every element (loops, MIDI, automation) snaps to the same grid. Q: Why does dotted-note delay sound more musical? A: A dotted quarter note lasts 1.5 beats. When a dotted-eighth delay (0.75 x beat) is set against a 4/4 groove it creates a three-against-four polyrhythm that feels like it is chasing the beat — the classic U2 / The Edge effect. The straight quarter note delay, by contrast, simply echoes every beat and can make the mix feel cluttered. Q: Can I use this tool offline? A: Yes — once the page is loaded, everything runs in your browser with no network calls. The Web Audio engine, tap-tempo logic and all calculations are entirely client-side. You can bookmark the page and return to it even without an internet connection if your browser has cached the assets. #### Scale Degree Calculator URL: https://geratools.com/scale-degree-calculator Free scale degree calculator: pick a root note and a scale or mode — Major, Minor, Pentatonic, Blues, Dorian, Lydian and more — and see every degree, note name, semitone count and equal-temperament frequency ratio. Runs entirely in your browser. How to use: 1. Choose a root note: Select any of the 12 chromatic pitches from C through B as your tonic. 2. Pick a scale or mode: Choose from 15 scales including Major, all 7 diatonic modes, Harmonic Minor, Blues and Whole Tone. 3. Read the degree table: Every scale step shows its degree number, Roman numeral, note name, enharmonic spelling, semitone distance and interval quality. 4. Explore the piano diagram: The inline keyboard highlights the active notes so you can see the pattern at a glance. 5. Click a row for details: Selecting any row in the table reveals the exact frequency ratio for that degree above the root. FAQ: Q: What is a scale degree? A: A scale degree is the position of a pitch within a scale, counted from 1 (the tonic or root) upward. In a 7-note scale the tonic is degree 1 and the leading tone is degree 7. Each degree has a traditional name — tonic, supertonic, mediant, subdominant, dominant, submediant and subtonic or leading tone — and a Roman numeral label used in harmonic analysis. Q: How do you calculate the notes in a major scale? A: The major scale follows the whole-step/half-step pattern W W H W W W H, which in semitones is 0, 2, 4, 5, 7, 9, 11. Add each value (mod 12) to the root pitch class to get each note. For C major: C(0) D(2) E(4) F(5) G(7) A(9) B(11). Q: What is the difference between a mode and a scale? A: A mode is a rotation of the diatonic (major) scale starting from a different degree. Dorian starts on degree 2, Phrygian on degree 3, and so on through Lydian, Mixolydian, Aeolian (Natural Minor) and Locrian. Each rotation has the same seven pitches as its parent key but a different tonal centre, producing a distinct emotional colour. Q: What do the Roman numerals mean? A: Roman numerals label each degree and hint at the chord built on it. Upper-case (I, IV, V) implies a major chord; lower-case (ii, iii, vi) implies minor; a degree symbol (vii°) means diminished; a plus sign (III+) means augmented. This system lets musicians communicate harmonic function across different keys — "go to the V" means the dominant chord regardless of root. Q: How does the frequency ratio work for each degree? A: In 12-tone equal temperament every semitone multiplies frequency by the twelfth root of two (2^(1/12)). A degree n semitones above the root has frequency ratio 2^(n/12). The perfect fifth (7 semitones) gives 2^(7/12) ≈ 1.4983, very close to the pure ratio 3:2 = 1.5000. Q: What scales are included? A: The calculator covers 15 scales: Major (Ionian), Natural Minor (Aeolian), Harmonic Minor, Melodic Minor (ascending), Dorian, Phrygian, Lydian, Mixolydian, Locrian, Major Pentatonic, Minor Pentatonic, Blues Hexatonic, Whole Tone, Diminished (whole-half octatonic) and Chromatic. ### Gaming #### Board Game Score Sheet Generator URL: https://geratools.com/board-game-score-sheet Track scores for any board game with a flexible digital sheet: add players, add scoring categories or rounds, enter points in a grid, and get live totals plus a ranked leaderboard. Works for Ticket to Ride, Catan, Wingspan, and more. How to use: 1. Add your players: Add a column for each player and rename it. Start with two and add more as needed. 2. Add scoring categories: Add a row for each round or scoring category your game uses, such as routes, eggs, or longest road. 3. Enter scores: Type each player's points in the grid. Totals and the leaderboard update automatically as you go. FAQ: Q: Which board games does this work with? A: Any game where players accumulate points across categories or rounds. It adapts to Ticket to Ride, Catan, Wingspan, Carcassonne, Azul, scorepad games, and most Euro and family titles by letting you name your own categories. Q: How are totals calculated? A: Each player's total is the sum of every value in their column across all categories. Blank cells count as zero, so partially filled sheets still total correctly. Q: How does the leaderboard rank players? A: The leaderboard sorts players from highest total to lowest and highlights the current leader. It updates instantly whenever you change a score, add a player, or add a category. Q: Can I handle negative points? A: Yes. Some games subtract points, for example unfinished routes in Ticket to Ride, so the cells accept negative numbers and the total reflects them correctly. Q: Is my game data saved anywhere? A: No. The sheet lives entirely in your browser for the current session and nothing is uploaded. Keep the tab open while you play. #### Chess Performance Rating Calculator URL: https://geratools.com/chess-elo-performance-rating Enter every opponent's rating plus your wins, draws, and losses to compute your tournament performance rating (TPR) with the FIDE rating-difference table and the linear 400-point method side by side. How to use: 1. List opponent ratings: Enter the rating of every opponent you faced, separated by commas or spaces — one per game. 2. Enter your record: Type your wins, draws, and losses. The total must equal the number of opponent ratings you listed. 3. Read your performance: See your performance rating from the FIDE table method, with the linear approximation and your average opposition shown alongside. FAQ: Q: What is a tournament performance rating? A: A performance rating (TPR) is the rating a player would need to have to expect the score they actually achieved against that field of opponents. It measures how strongly you played in a single event, independent of your official rating. Q: How does the FIDE table method work? A: Take your average opponent rating, then add a rating difference (dp) read from the FIDE table for your score percentage. A 50% score adds zero, higher percentages add a positive dp up to +800, and lower percentages subtract it. Q: What is the linear 400-point method? A: The linear approximation is average opponent rating plus 400 times (wins minus losses) divided by games. It is quick and widely quoted but overstates performance at very high or very low scores, where the true curve flattens. Q: Why must the opponent count match my games? A: Each game has exactly one opponent, so the number of ratings you enter must equal wins plus draws plus losses. The tool warns you if they do not match so the average and percentage stay correct. Q: Does a perfect score give a real rating? A: A 100% score has no finite performance rating in theory, so FIDE caps it at average opponent rating plus 800. The tool applies the same +800 cap for a clean sweep. #### D&D Advantage/Disadvantage Calculator URL: https://geratools.com/dnd-advantage-disadvantage-odds Computes exact hit probabilities for d20 rolls with normal, advantage, disadvantage, and Elven Accuracy, given any modifier and target DC. See the percentage-point swing and crit odds. Essential for D&D 5e players valuing advantage. How to use: 1. Enter your modifier: Type your to-hit bonus or saving-throw modifier that is added to the d20. 2. Enter the target DC: Type the target Armor Class or save DC you are rolling against. 3. Compare the four modes: The tool shows hit chance for disadvantage, normal, advantage, and Elven Accuracy, the point swing versus normal, the mean d20 result, and crit odds. FAQ: Q: How is advantage calculated exactly? A: Advantage means rolling two d20 and taking the higher. The chance the result is at most k is (k/20) squared, so the chance of exactly k is (k/20) squared minus ((k-1)/20) squared. Disadvantage uses the lower die with the mirrored formula. Both are exact, not simulated. Q: How much does advantage improve my roll? A: It depends on the target. Advantage helps most when you need a middling roll, adding up to about 25 percentage points near a 50% hit chance, and helps least at the extremes. The tool shows the exact point swing for your DC. Q: What is Elven Accuracy? A: Elven Accuracy is a 5e feat that lets certain characters reroll one die when they have advantage, effectively rolling three d20 and taking the highest. The calculator models this as take-highest-of-three, which also roughly triples the natural-20 crit chance to about 14.3%. Q: How do natural 1 and natural 20 affect the result? A: Following attack-roll rules, a natural 20 always hits regardless of the target and a natural 1 always misses. The hit percentages include this, which is why a high-modifier attack against a low DC still has a small miss chance from rolling a 1. Q: Does advantage change my critical hit chance? A: Yes. A normal roll crits on a natural 20 5% of the time. Advantage raises that to about 9.75% because you have two chances to roll a 20, and Elven Accuracy raises it to about 14.26% with three dice. #### D&D Multiclass Proficiency & Spell Slot Tracker URL: https://geratools.com/dnd-class-level-multiclass-proficiency Enter each class and level of a D&D 5e multiclass character to compute total level, proficiency bonus, effective multiclass caster level, and the combined spell-slot table from the Player's Handbook rules. How to use: 1. Add each class and level: Add a row for every class in your build and enter the level you have in each. Add or remove rows as you plan dips and splits. 2. Read your core numbers: The tool sums your total character level, derives the shared proficiency bonus, and computes the effective multiclass caster level used for spell slots. 3. Check your spell slots: The combined spell-slot table appears below, following the Player's Handbook multiclass rules. Warlock Pact Magic is flagged as tracked separately. FAQ: Q: How is the proficiency bonus calculated for a multiclass character? A: Proficiency bonus depends only on total character level, not on individual class levels. It equals 2 plus the floor of (total level minus 1) divided by 4, so it is plus 2 at levels 1 to 4, plus 3 at 5 to 8, and rises by one every four levels up to plus 6 at level 17. Q: How does multiclass spellcasting determine spell slots? A: You add full caster class levels in full, half of your half-caster levels (Paladin, Ranger) rounded down, and a third of your third-caster levels (Eldritch Knight, Arcane Trickster) rounded down. That sum is your effective caster level, which you look up on the Player's Handbook multiclass slot table. Q: Why does a Fighter 5 / Wizard 3 not get level-4 wizard slots? A: Only the Wizard 3 counts toward caster level for a standard Fighter, giving an effective caster level of 3 and the slots a third-level caster has. The Fighter levels add hit points, attacks, and proficiency but no caster levels unless it is the Eldritch Knight subclass, which counts as a third caster. Q: How is Warlock handled? A: Warlock uses Pact Magic, which does not combine with the normal multiclass slot table. Its slots are tracked separately, are all the same level, and recharge on a short rest. The tool flags this so you do not accidentally merge Pact slots into your regular spell slots. Q: Does total level cap at 20? A: Yes, standard 5e characters cap at level 20, and the multiclass caster level used for slots also caps at 20. If your entered levels sum above 20 the tool warns you and caps the caster level and slot lookup at the level-20 row. #### D&D Custom Monster CR Builder URL: https://geratools.com/dnd-cr-challenge-rating-builder Enter your homebrew monster's hit points, armour class, attack bonus, damage per round, and save DC to compute defensive and offensive challenge ratings using the Dungeon Master's Guide tables, then average them into a final CR for D&D 5e DMs. How to use: 1. Enter defensive stats: Type your monster's hit points and armour class. The tool finds the defensive CR from the HP, then adjusts it for AC that is higher or lower than expected. 2. Enter offensive stats: Type the average damage the monster deals per round over its first three rounds, plus its attack bonus or save DC. This sets the offensive CR. 3. Read the final CR: The tool averages the defensive and offensive CR, rounds to the nearest valid CR, and reports the matching proficiency bonus and XP value. FAQ: Q: How does the DMG compute challenge rating? A: The Dungeon Master's Guide derives a defensive CR from hit points adjusted by armour class, and an offensive CR from damage per round adjusted by attack bonus or save DC. The final CR is the average of the two, rounded to the nearest CR on the table. Q: How is the AC adjustment applied? A: Each HP band has an expected AC. If your monster's AC is two points above or below that expected value, the defensive CR shifts up or down by one step per two points of difference. Very tanky or very squishy monsters are rated accordingly. Q: What counts as damage per round? A: Use the average total damage the monster deals across its first three rounds of combat, then take the mean per round. Include multiattack, but assume its most damaging realistic action sequence rather than a perfect or worst case. Q: Should I trust the number blindly? A: Treat it as a strong starting point. The DMG maths captures raw numbers but not abilities like flight, invisibility, legendary actions, or area control, which can make a monster play above its CR. Adjust based on how it actually performs at the table. Q: What proficiency bonus does my CR use? A: Proficiency bonus rises with CR: it is plus 2 up to CR 4, plus 3 from CR 5 to 8, plus 4 from CR 9 to 12, and so on. The tool reports the matching proficiency bonus and the XP award for the final CR alongside the result. #### D&D Damage Per Round (DPR) Calculator URL: https://geratools.com/dnd-damage-per-round-calculator Enter attack bonus, target AC, damage dice, crit range, and roll type to get average damage per round with correct critical-hit math and advantage support. For D&D 5e players comparing weapons, builds, and class features. How to use: 1. Enter your attack and target: Type your attack bonus and the target's Armor Class so the tool can compute your hit chance. 2. Enter damage dice and modifier: Put your weapon or spell dice like 1d8 or 1d8+2d6 in the dice field, and any flat bonus such as your ability modifier in the flat field. 3. Set crit range, roll type, and attacks: Choose your critical range, whether you roll normal, advantage, or disadvantage, and how many attacks you make, then read your DPR. FAQ: Q: How is DPR calculated? A: DPR is your hit chance times average damage on a hit, plus extra damage from crits. A crit doubles the damage dice but not the flat modifier, so the tool computes (hit minus crit chance) times normal hit damage, plus crit chance times crit damage, then multiplies by your number of attacks. Q: Does it handle critical hits correctly? A: Yes. On a critical hit you roll the damage dice twice but add the flat modifier only once. The calculator separates the crit portion of your hit chance and applies doubled dice to it, which is the official 5e rule and a common source of errors in hand math. Q: How does advantage affect DPR? A: Advantage raises your hit chance and roughly doubles your natural-20 crit chance, both of which increase DPR. Select advantage or disadvantage and the tool recomputes the per-face probabilities exactly, so you can see the real damage swing from a feature like Faerie Fire. Q: Where do I put my Strength or Dexterity bonus? A: Put ability and other flat bonuses in the flat damage modifier field, and keep only dice like 1d8 in the dice field. Flat bonuses are added once per hit and are not doubled on a crit, so separating them keeps the math correct. Q: Can I model an expanded crit range like a Champion Fighter? A: Yes. Set the crit range to 19-20 or 18-20 to model a Champion Fighter's Improved Critical. A wider crit range increases the share of hits that deal doubled dice, raising DPR, especially for builds with large dice or extra crit dice. #### D&D Hit Points Calculator URL: https://geratools.com/dnd-hit-points-calculator Enter class hit dice, level, and Constitution modifier to compute maximum HP, average (fixed) HP, and a hit-dice summary for D&D 5e. Supports multiclassing across several classes in one build. How to use: 1. Add each class and its levels: Pick a hit die (d6 to d12) and the number of levels in that class. Add another row for each class in a multiclass build. 2. Enter your Constitution modifier: Type your CON modifier (for example +2). It is added to HP for every character level, not per class. 3. Read max and average HP: The tool shows maximum HP (taking the full die each level) and average HP (the fixed value most tables use after level 1). FAQ: Q: How does first-level HP work in D&D 5e? A: At level 1 you take the maximum of your first class's hit die plus your Constitution modifier. A level 1 Fighter (d10) with +2 CON starts with 10 + 2 = 12 HP. Every level after that follows the rolled or average rule. Q: What is the difference between max and average HP? A: Max HP assumes you take the full hit die on every level-up, which is the absolute ceiling. Average HP uses the fixed value in the rules (half the die plus 1, such as 6 on a d10), which is what most groups use instead of rolling. Q: How is the average per level calculated? A: For a die with X sides, the average gain per level after the first is X divided by 2, plus 1, plus your Constitution modifier. A d8 gives 5 per level, a d10 gives 6, and a d12 gives 7, before adding CON. Q: How does multiclassing affect HP? A: Each class contributes its own hit die per level, but only your very first character level gets the maximum starting roll. Every subsequent level from any class uses the rolled or average value, and your Constitution modifier is added to each. Q: Does increasing my Constitution modifier raise past HP? A: Yes. Constitution applies retroactively to every level. If your CON modifier goes from +2 to +3 at level 8, all eight levels gain 1 HP each, for a total of 8 extra hit points. #### D&D Treasure / Loot Generator URL: https://geratools.com/dnd-loot-treasure-generator Roll random D&D 5e treasure by encounter Challenge Rating using the Dungeon Master's Guide individual and hoard tables. Get coins, gems, art objects, and magic-item table references in one click for fast loot after combat. How to use: 1. Set the Challenge Rating: Enter the CR of the creature or encounter you just resolved. The tool picks the correct DMG table band (0-4, 5-10, 11-16, or 17+). 2. Pick the treasure type: Choose Individual treasure for coins carried by a single creature, or Hoard for a stockpile that may include gems, art objects, and magic items. 3. Roll the loot: Press Roll treasure. You get coins by denomination, any valuables with their gold value, and which DMG magic-item table to roll on. FAQ: Q: Which D&D edition do these tables use? A: They follow the 5th edition Dungeon Master's Guide treasure tables in Chapter 7. The CR bands and coin multipliers match the individual-treasure and treasure-hoard tables exactly. Q: What is the difference between individual treasure and a hoard? A: Individual treasure is the loose coin a single monster carries, rolled per creature. A hoard is a larger cache — a dragon's lair or bandit stash — that adds gems, art objects, and a chance of magic items on top of the coins. Q: Why does it only name the magic-item table instead of a specific item? A: Hoards direct you to roll on Magic Item Tables A through I depending on rarity. The tool tells you which table and how many rolls so you can roll the specific items on your sheet or app and keep full DM control. Q: How is the total gold value calculated? A: Coins are converted at the standard 5e rate: 1 pp = 10 gp, 1 gp = 1 gp, 1 ep = 0.5 gp, 1 sp = 0.1 gp, 1 cp = 0.01 gp. Gems and art objects add their listed gold value. Q: Is the result the same every time? A: No. Each roll uses fresh random dice locally in your browser, just like rolling at the table. Press the button again for a different result for the next encounter. #### D&D Proficiency Bonus & Skill Check Calculator URL: https://geratools.com/dnd-proficiency-bonus-calculator Enter your D&D 5e character level, the six ability scores, and which skills and saves you are proficient in to generate a complete table of skill check and saving throw modifiers, including expertise. For new and leveling players. How to use: 1. Enter level and ability scores: Type your character level (1 to 20) and your six ability scores: Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma. 2. Mark your proficiencies: Check the skills and saving throws you are proficient in, and mark any skills where you have expertise to double the bonus. 3. Read the bonus table: The tool shows your proficiency bonus, each ability modifier, and the full table of skill check and saving throw modifiers to copy onto your sheet. FAQ: Q: How is the ability modifier calculated? A: The modifier is the ability score minus 10, divided by 2, rounded down. A score of 16 gives a +3 modifier, 14 gives +2, 10 or 11 gives +0, and 8 gives -1. This is the core of every check in 5e. Q: How does proficiency bonus scale with level? A: Proficiency bonus is +2 at levels 1 to 4, +3 at 5 to 8, +4 at 9 to 12, +5 at 13 to 16, and +6 at 17 to 20. The formula is 2 plus the level minus 1, divided by 4, rounded down. Q: What is expertise? A: Expertise doubles your proficiency bonus for a specific skill. Rogues and bards gain it. A proficient character with expertise in Stealth and a +3 proficiency bonus adds +6 from proficiency on top of the relevant ability modifier. Q: Which ability does each skill use? A: Each skill keys off a fixed ability: Athletics uses Strength; Acrobatics, Sleight of Hand, and Stealth use Dexterity; Arcana, History, Investigation, Nature, and Religion use Intelligence; Animal Handling, Insight, Medicine, Perception, and Survival use Wisdom; and Deception, Intimidation, Performance, and Persuasion use Charisma. Q: Does this include feats or magic items? A: No. It computes the base modifier from ability score, proficiency, and expertise only. Add bonuses from feats, magic items, fighting styles, or spells separately when filling out your sheet. #### D&D XP to Next Level Tracker URL: https://geratools.com/dnd-xp-level-progression Enter your current XP and level to see XP needed to reach the next level, your percentage progress through the current level, and the full PHB experience table. For D&D 5e players using XP advancement. How to use: 1. Enter your current XP: Type your character's total accumulated experience points from your character sheet. 2. Read your level and progress: The tool derives your current level from the official 5e XP table and shows how far you are through it. 3. See what is left to the next level: It reports the XP still needed to reach the next level and highlights your current row in the full table. FAQ: Q: What XP table does this use? A: It uses the official Dungeons & Dragons 5th Edition experience table from the Player's Handbook: level 1 at 0 XP, level 2 at 300, level 3 at 900, up to level 20 at 355,000 XP. Your level is whatever band your total XP falls into. Q: How is percentage progress calculated? A: It takes your XP above the current level's threshold and divides by the size of the band to the next level. At 1,200 XP (level 3 starts at 900, level 4 at 2,700) you are 300 of 1,800 through, or about 17 percent. Q: What happens at level 20? A: Level 20 is the cap in standard 5e. Once you reach 355,000 XP there is no further level, so the tool shows you at the maximum level with no XP remaining to a next level. Epic boons are the usual way to progress beyond. Q: Does this work with milestone leveling? A: Milestone leveling ignores XP entirely — the DM grants levels at story beats. This tracker is for tables using the XP variant. If your group uses milestones you will not be tracking the numbers this tool needs. Q: How is XP awarded in 5e? A: Monsters and challenges have XP values that the DM divides among the party after an encounter. The exact awards are up to the DM and adventure. This tool only tracks the total you have banked against the leveling table. Q: Does the multiple-monster XP multiplier increase the XP we earn? A: No. The multiplier (×1.5 for two monsters, ×2 for three to six, and so on) is used only when the DM estimates encounter difficulty. The party banks the monsters' base XP values, split among the characters. Awarding multiplied XP is a common mistake that makes parties level far too fast. #### Dota 2 Enchant & Gear Score Calculator URL: https://geratools.com/dota-2-enchant-gear-calculator Set an item tier, base success rate and decay to see per-level enchant probabilities, the average number of attempts, and the expected total cost to reach your target enchant level using geometric-trial math. How to use: 1. Set start and target levels: Enter your current enchant level and the level you want to reach. 2. Describe the success curve: Set the base success rate at level zero, how fast it decays per level, a floor rate, and the cost per attempt. 3. Read the cost forecast: The tool shows each level's success rate, average attempts and average cost, then totals the expected attempts and gold. FAQ: Q: How is the expected number of attempts calculated? A: Each attempt is an independent trial with success probability p, so the number of attempts to land one success follows a geometric distribution with mean 1 divided by p. The tool computes this per level and sums across the range you want to upgrade. Q: Why does the success rate fall as the level rises? A: Most enchant systems make each step harder than the last. The tool models this with a per-level decay: the rate at level L is the base rate multiplied by the decay factor raised to L, clamped at a minimum floor so it never reaches zero. Q: Is the total cost a guarantee? A: No. It is the statistical average. A single playthrough can finish well under or well over the total because each attempt is random. Budget toward the expected total rather than a lucky best case. Q: What does the floor rate do? A: The floor is the minimum success chance an attempt can have no matter how high the level. It prevents the decay curve from driving the rate to an impossible value and keeps the expected attempts finite. Q: Can I model a system with no failure penalty? A: Yes. This tool assumes a failed attempt only costs the attempt cost (materials or gold) and does not destroy the item. If your game downgrades or destroys gear on failure, treat the result as a lower bound on true cost. #### Final Fantasy XIV Time-to-Max-Level Calculator URL: https://geratools.com/ffxiv-time-to-level-calculator Enter your current level, the level cap, XP per hour from your levelling method, and hours played per day to forecast a realistic day-by-day timeline to the cap, using an escalating per-level XP curve. Runs in your browser. How to use: 1. Enter your levels: Type your current level and the level cap you want to reach. 2. Set XP rate and curve: Enter the XP your method earns per hour, the XP needed at your current level, and how much each level multiplies the requirement. 3. Read the timeline: The tool totals the XP across all remaining levels, divides by your hourly rate, and converts to days at your daily play hours. FAQ: Q: How does the XP curve work? A: Most games raise the XP needed each level by a roughly constant multiplier. The tool starts from the XP needed at your current level and multiplies it by your growth factor for each subsequent level, summing the total to reach the cap. Q: Why use a multiplier instead of a flat XP per level? A: A flat requirement underestimates late-game grind badly. A 1.1 multiplier means level 80 needs far more XP than level 10, which matches how real levelling curves stretch out near the cap. Set the multiplier to 1 for a flat curve. Q: How are days calculated from total hours? A: Total hours equals total XP needed divided by XP per hour. Dividing those hours by your hours played per day gives calendar days. The tool also shows total hours separately so you can plan sessions. Q: What XP-per-hour figure should I enter? A: Use the throughput of your actual method — dungeon spam, hunts, FATEs, or quests — from a parser or your own timed run. Rates vary widely, so an accurate per-hour number is the single biggest driver of the forecast's accuracy. Q: Does rest XP or bonus XP change the result? A: Indirectly. If a rest or bonus buff roughly doubles your effective XP per hour, enter the boosted rate. The tool models a single steady rate, so for variable bonuses use a blended average across your expected play. #### Lorcana Willpower & Lore Race Calculator URL: https://geratools.com/lorcana-willpower-damage-calculator Model Disney Lorcana combat by entering character strength and willpower, see whether a challenge banishes a character, and calculate how many turns of questing it takes each player to reach 20 lore and win. How to use: 1. Enter the two characters: Type the strength and willpower of the challenging character and the one being challenged. 2. Read the challenge outcome: The tool compares damage dealt to remaining willpower on both sides and tells you which characters are banished. 3. Race the lore: Enter each player's current lore and lore gained per turn to see how many turns each needs to reach 20 and who wins the race. FAQ: Q: How does damage work in Disney Lorcana? A: When a character challenges another, each deals damage equal to its strength to the other. A character is banished when total damage on it equals or exceeds its willpower. Damage stays on a character across turns unless an effect heals it, so it accumulates. Q: What is willpower in Lorcana? A: Willpower is a character's effective health, shown by the heart icon. A character can absorb damage up to but not including its willpower and survive; once damage reaches its willpower it is banished to the discard pile. This tool compares damage to willpower to decide banishment. Q: How many lore do I need to win? A: A player wins the moment they reach 20 lore. Lore is gained mainly by questing with characters, where each character's lore value, the number beside the diamond icon, is added on the turn it quests. Reaching 20 first ends the game immediately. Q: Why model the lore race? A: Lorcana is fundamentally a race to 20 lore, so knowing how many turns each player needs at their current lore-per-turn rate tells you whether to keep questing or switch to challenging the opponent's questers to slow them down. Q: Does a character have to challenge to deal damage? A: Generally yes; a ready character can challenge an exerted opposing character, and both deal their strength as damage. Characters that just quested are exerted and can be challenged but cannot challenge back until they ready, which the strategy notes account for. #### MTG Draft Pick Evaluation Tool URL: https://geratools.com/magic-draft-pick-order Enter cards in a draft pack with a power rating, color, and mana value to get a recommended pick order weighted by raw power, how well each card fits your developing colors, and your curve gaps. For Magic: The Gathering booster draft. How to use: 1. Set your current colors: Mark the one or two colors you are leaning into. Cards in those colors get a commitment bonus; off-color cards are penalized. 2. Add the cards in the pack: For each card enter a name, its base power rating (0 to 5), its color, and its mana value so the tool can weigh curve needs. 3. Read the ranked pick order: The tool combines raw power, color fit, and curve need into a score and sorts the cards from best to worst pick. FAQ: Q: How is each card's pick score calculated? A: The score starts from your base power rating, then adds a bonus when the card matches your chosen colors and a smaller penalty when it does not. A modest curve bonus is added for cards that fill a mana value you are light on, so power is the main driver but fit breaks ties. Q: What power rating should I give a card? A: Use a 0 to 5 bomb scale: 5 for a game-winning bomb, 4 for a premium removal spell or strong creature, 3 for a solid playable, 2 for filler, and 0 to 1 for cards you would rarely run. Consistency between cards matters more than the exact number. Q: Why does color commitment matter in draft? A: Booster draft rewards staying open early then committing to two colors. Once you commit, on-color cards are far more likely to make your 40-card deck, so a slightly weaker on-color card often out-values a stronger off-color one you may never cast. Q: How does the curve bonus work? A: The tool tracks how many cards you have at each mana value. When a card fills a slot you are short on (often two and three drops), it gets a small bonus, nudging you toward a playable curve rather than a pile of expensive bombs. Q: Does this replace reading signals? A: No. The tool ranks the cards in front of you, but it cannot see what is being passed. Use it to compare picks within a pack, then adjust based on open colors and what your neighbors seem to be taking. #### MTG Commander Color Identity Checker URL: https://geratools.com/mtg-edh-commander-color-identity Set your commander's color identity, then paste card mana costs to flag any card that falls outside it. Implements the real EDH rule covering mana symbols and rules-text symbols. For Magic: The Gathering Commander players. How to use: 1. Set the commander color identity: Tick the W/U/B/R/G colours that appear in your commander's mana cost and rules text. That is the deck's allowed identity. 2. Paste your card list: Enter one card per line with its mana symbols, for example "Lightning Bolt {R}" or just the symbols {1}{G}{U}. 3. Read the legality flags: The tool extracts each card's colour pips and marks any card that uses a colour outside the commander's identity as illegal. FAQ: Q: What is color identity in Commander? A: A card's color identity is the set of colors of its mana symbols anywhere on the card, including in casting cost and rules text, plus any color indicator. In Commander, every card's identity must be a subset of the commander's identity. Q: Do colorless and generic mana count? A: No. Generic mana like {2} and truly colorless {C} symbols add no colored identity. Only the five colored pips W, U, B, R and G contribute, so a 7-mana artifact with no colored pips fits any deck. Q: What about hybrid and Phyrexian symbols? A: Hybrid pips like {W/U} contribute both colors to identity. Phyrexian pips like {W/P} still contribute their color. This tool counts each colored letter inside a brace group, so {B/G} adds both black and green. Q: Does rules-text mana count too? A: Yes. A card like a land that taps for {G} or an ability that says add {R} carries that color in its identity even with a colorless mana cost. Paste any such symbols on the line so the checker sees them. Q: Why is my mono-color deck flagging a card? A: If a flagged card shows an extra pip, it has a colored symbol somewhere your commander does not allow. Even a single off-color hybrid or activated-ability pip makes the card illegal in that deck. #### MTG Hypergeometric Draw Calculator URL: https://geratools.com/mtg-hypergeometric-draw Calculate the exact probability of drawing N copies of a card in X draws from a Magic: The Gathering deck of any size, using the hypergeometric distribution. Get exactly, at-least, and at-most odds plus the full distribution — runs in your browser. How to use: 1. Enter the four deck values: Type the deck size, the number of copies of the card in the deck, how many cards you will draw, and how many copies you want. 2. Choose at-least or exactly: Select whether you want the probability of at least k copies or exactly k copies in your draw. 3. Read the odds and distribution: The tool shows the chosen probability, the exactly and at-most figures, and an expandable table of the full distribution. FAQ: Q: What is the hypergeometric distribution? A: It is the probability model for drawing without replacement from a finite population. In Magic, your deck is the population, the copies of a card are the successes, and your draw is the sample. It is the correct model for card draws because once you draw a card it cannot be drawn again. Q: How is the probability calculated? A: The exact probability of drawing k copies is C(K, k) times C(N minus K, n minus k) divided by C(N, n), where N is deck size, K is copies in deck, n is cards drawn, and C is the binomial coefficient. The tool sums these terms to produce at-least and at-most figures. Q: Why not just use a simple percentage? A: Because draws are not independent. After you draw one copy, fewer copies and fewer total cards remain, so the odds of the next draw change. The hypergeometric distribution accounts for this exactly, while a naive percentage does not. Q: Can I use this for the opening hand? A: Yes. Set cards drawn to 7 for a typical opening hand. To model later turns, increase the draw count by one per turn drawn. The calculation is identical for any sample size up to the deck size. Q: Is this accurate for large Commander decks? A: Yes. The tool uses log-factorials internally, so it stays numerically stable and accurate for decks of 100 cards or more without overflow errors. #### MTG Land Count Optimizer URL: https://geratools.com/mtg-land-count-optimizer Input your deck's average mana value and a few modifiers to get a statistically grounded land count using Frank Karsten's land formula. Tune Limited, Constructed, or Commander mana bases for consistency — runs entirely in your browser. How to use: 1. Choose your deck size: Select 40, 60, or 100 cards so the formula scales correctly for your format. 2. Enter average mana value and modifiers: Type your deck's average converted mana cost, the number of cheap cantrips or cycling cards, and the number of ramp or modal double-faced land cards. 3. Read the recommended land count: The tool returns a recommended land count with a flexible range and the underlying base and adjusted figures. FAQ: Q: What is Frank Karsten's land formula? A: Frank Karsten, a Magic pro and mathematician, derived a near-linear relationship between a deck's average mana value and the number of lands it should run. For a 60-card deck the guideline is roughly 16.37 plus 3.42 times the average mana value, with adjustments for cheap card advantage and ramp. Q: How do cantrips and ramp change the count? A: Cheap card-draw and cycling cards smooth your draws, so the model trims about one land per three such cards. Ramp sources and modal double-faced lands that can be played as lands count as roughly half a land each toward your effective land base. Q: Does this work for Commander or Limited? A: Yes. The base formula was derived for 60-card Constructed, so the tool scales the result linearly to a 40-card Limited deck or a 100-card Commander deck. Commander mana bases also depend heavily on color requirements, so treat the figure as a floor. Q: Is the recommendation a hard rule? A: No. It is a statistically grounded starting point. Aggressive decks that want to curve out flawlessly may run slightly more lands, while combo decks that win from the hand can sometimes run fewer. Use the flexible range as your tuning window. Q: Why does a higher average mana value need more lands? A: A deck full of expensive spells must reliably reach higher mana totals, which requires hitting land drops for more consecutive turns. More lands raise the chance of an uninterrupted mana progression, so the formula adds lands as the average mana value rises. #### MTG Mana Curve Analyzer URL: https://geratools.com/mtg-mana-curve-analyzer Enter your spells by mana value and get a mana-curve histogram, average CMC, and a recommended land count for your Magic: The Gathering deck. Tune Limited, Constructed, or Commander lists for consistency — runs entirely in your browser. How to use: 1. Pick your deck size: Choose 40 (Limited), 60 (Constructed), or 100 (Commander) so the recommended land count scales correctly. 2. Enter spells by mana value: Type how many non-land cards sit at each converted mana cost from 0 up to 7+, then enter your current land count. 3. Read the curve and recommendation: The histogram shows your distribution, and the tool reports average CMC plus a recommended land count to flag flood or screw risk. FAQ: Q: What is a mana curve in Magic? A: A mana curve is the distribution of your deck's cards by converted mana cost (mana value). A smooth curve weighted toward cheap spells lets you cast something useful on most turns, which is one of the biggest drivers of a deck's consistency. Q: How is average CMC calculated? A: The tool sums the mana value of every non-land card and divides by the number of spells. The 7+ bucket is counted as exactly 7, so the average is a slight underestimate for very top-heavy decks. Lands are excluded because they have no mana value. Q: How many lands should my deck run? A: The recommendation starts from the standard ratio for your format (about 42.5% for 40-card Limited, 40% for 60-card Constructed) and nudges it up or down by one or two lands based on your average mana value. Higher curves want more lands; aggressive low curves can run slightly fewer. Q: What does a good mana curve look like? A: For most aggressive and midrange decks the peak sits at one or two mana, tapering off toward higher costs. Control decks can carry a higher curve because they expect to reach the late game. There is no single ideal shape — it depends on your deck's plan. Q: Does this account for X spells or alternate costs? A: No. Cards with X in their cost, alternate casting costs, or mana value reducers are entered at whatever value you decide best represents them. The tool works purely from the buckets you input, so use your judgement for unusual cards. #### MTG Mulligan Probability Calculator URL: https://geratools.com/mtg-mulligan-probability Calculate the probability that your Magic: The Gathering opening 7 (or post-mulligan 6 and 5) contains the cards you need, using the exact hypergeometric distribution. Decide when to keep and when to mulligan with real numbers — runs in your browser. How to use: 1. Enter your deck and card counts: Type your deck size, how many copies of the key card it contains, and how many copies you need to keep a hand. 2. Choose your turn-1 position: Pick whether you are on the play or on the draw so the by-turn-1 figure accounts for the extra card. 3. Read the keep odds: The tool shows the chance your opening 7, a 6, and a 5 each contain enough copies, plus the odds of finding a keepable hand within a few mulligans. FAQ: Q: How is the opening-hand probability calculated? A: The chance of drawing at least the number of copies you need in your opening 7 is computed with the hypergeometric distribution, which models drawing without replacement from a finite deck. It is exact, not an approximation, for a single hand. Q: Does this use the London mulligan rule? A: Yes, in spirit. Under the London mulligan you always draw 7 cards and then bottom one card per mulligan taken. The keep-7, keep-6, and keep-5 figures show how likely it is that a hand of that final size contains your requirement. Q: Why are the multi-mulligan odds an estimate? A: The figure for finding a keepable hand within two or three mulligans uses the standard 1 minus (1 minus p) to the power of attempts formula. This slightly overstates the true odds because successive mulligans are not fully independent, but it is the quick estimate most players rely on. Q: Should I keep a one-lander or mulligan? A: That depends on your deck and the matchup, but the numbers help. If your deck needs at least two or three specific cards to function, this calculator shows how rarely a random 7 delivers them, which often justifies a mulligan to dig for a more functional hand. Q: What counts as a key card? A: A key card can be a single named card, a category like lands, or any group you treat as interchangeable. Enter the total copies of that group in your deck and the number you need in hand to keep, and the math works the same way. #### Pathfinder 2e Point Buy Calculator URL: https://geratools.com/pathfinder-point-buy Walk through ancestry, background, class, and four free ability boosts in Pathfinder 2e to get final attribute scores and modifiers. The official boost-and-flaw system, fully tracked in your browser. How to use: 1. Start from base 10s: Every ability begins at 10. The calculator starts there and applies boosts and flaws from each step of character creation. 2. Apply boosts and flaws: Add the ancestry, background, class, and four free boosts. A boost adds 2 below 18 and only 1 at or above 18; a flaw subtracts 2. 3. Read final scores and modifiers: The tool shows each final ability score and its modifier using the floor((score - 10) / 2) rule used throughout Pathfinder 2e. FAQ: Q: Why does a boost give only +1 above 18? A: In Pathfinder 2e, ability boosts add 2 points while the score is below 18, but only 1 point once it reaches 18 or higher. This soft cap keeps starting scores from running away at level 1, so an 18 boosted again becomes 19, not 20. Q: How are ability modifiers calculated? A: The modifier is floor((score minus 10) divided by 2). A score of 10 or 11 gives +0, 12 to 13 gives +1, 18 to 19 gives +4, and so on. This is the same rule used for checks, saves, and attacks. Q: What boosts do I get at character creation? A: A typical level 1 character gets one ancestry boost (plus a free one and often a flaw), one background boost, one class key-ability boost, and four free boosts you can place anywhere, with the rule that no single ability can take more than one of the four free boosts. Q: Can I apply two boosts to the same ability? A: Yes, as long as they come from different sources. You cannot place two of your four free boosts on the same ability, but a free boost can stack with an ancestry, background, or class boost on the same score. Q: Does this use the Pathfinder Remaster rules? A: The boost-and-flaw math is identical in the original Core Rulebook and the Remaster (where boosts are called attribute boosts). This calculator applies the same plus-2 below 18, plus-1 at 18 logic that both editions share. #### RuneScape 3 XP & Level Calculator URL: https://geratools.com/runescape-3-xp-level-calculator Input your current level and XP in RuneScape 3 to see exactly how much experience remains to the next level and to a target level, computed from the game's real cumulative XP table formula used across all skills. How to use: 1. Enter your current XP: Type your current total experience in the chosen skill, which the game shows when you hover the skill in your stats panel. 2. Set a target level: Choose the level you want to reach, up to 99 for normal skills or higher for elite skills. 3. Read the XP remaining: The tool computes the exact XP required for both your current and target level from the official formula and shows the gap, plus how far you are through your current level. FAQ: Q: What XP formula does RuneScape use? A: RuneScape sums a per-level term across all levels below your target. For each level L the increment is the floor of L plus 300 times 2 to the power of L divided by 7, all divided by 4. The cumulative XP for a level is one quarter of the running total of those increments. Q: How much XP is level 99? A: Reaching level 99 in a normal RuneScape skill requires 13,034,431 experience. This calculator reproduces that exact figure from the formula, so any target between 1 and 99 returns the same numbers the game uses. Q: Why does each level cost so much more than the last? A: The formula contains a term that doubles roughly every seven levels, so XP requirements grow exponentially. The jump from 98 to 99 alone is over 1.3 million experience, more than levels 1 through 70 combined. Q: Can I calculate elite skill levels above 99? A: This tool covers the standard 1 to 99 curve that applies to most skills. Elite skills such as Invention use a different, steeper table beyond 99, so figures above level 99 are not represented here. Q: What does percent through level mean? A: It shows how far your current XP has progressed between the start of your current level and the start of the next one, as a percentage. At 50 percent you are halfway, in XP terms, to the next level up. #### TCG Swiss Tournament Round Calculator URL: https://geratools.com/tcg-tournament-swiss-rounds Enter your player count to get the recommended number of Swiss rounds from the standard DCI attendance table, the mathematical minimum of ceil log2 players, the suggested top cut, and the points needed for an X-2 finish. For Magic, Pokemon and Yu-Gi-Oh organizers. How to use: 1. Enter the player count: Type how many players are registered for your tournament. The tool handles any whole number from a small store event to a large regional. 2. Read the recommended rounds: The calculator shows the standard recommended Swiss rounds for that attendance, plus the pure mathematical minimum derived from ceil log2 of the players. 3. Plan the cut and records: Use the suggested top cut and the points needed for an X-2 finish to communicate to players what record they need to make the playoff. FAQ: Q: How many Swiss rounds do I need? A: The mathematical minimum is ceil(log2(players)), because each Swiss round halves the number of players who can still be undefeated. Official events use a fixed attendance table on top of that — for example 5 rounds for 17 to 32 players and 6 rounds for 33 to 64 players. Q: Why is the recommended number sometimes higher than log2? A: The pure log2 value only guarantees a single undefeated player. Organisers add rounds so that records spread out cleanly and an X-2 record reliably separates the top cut, which improves fairness and tiebreaker resolution at larger events. Q: What should the top cut be? A: Common practice is no cut or a Top 2 final under 9 players, Top 4 for 9 to 16, and Top 8 for 17 players and up. Very large events occasionally run Top 16, but Top 8 is the standard single-elimination playoff size. Q: How do Swiss points work? A: A win is worth 3 points, a draw 1 point and a loss 0 points. After r rounds the maximum is 3r points. A player who loses at most twice (an X-2 record) earns 3 times (r minus 2) points and usually makes a Top 8. Q: Does this work for Magic, Pokemon and Yu-Gi-Oh? A: Yes. All three use Swiss pairings with the same 3-1-0 scoring and very similar attendance-based round tables, so the recommended rounds and top cut apply across them. Always check the current official rules document for your specific event tier. #### Terraria DPS Calculator URL: https://geratools.com/terraria-dps-calculator Compute accurate Terraria DPS from weapon base damage, percent and flat bonuses, crit chance, use time in ticks, enemy defense, and difficulty, using the game's real damage and defense-reduction rules. Compare builds and gear at a glance. Runs in your browser. How to use: 1. Enter weapon and bonuses: Type the weapon's base damage, total percent damage bonus, any flat damage added, and crit chance. 2. Add timing and target stats: Enter the use time in ticks, the enemy's defense, the difficulty, and your hit rate. 3. Read the DPS: The tool applies bonuses, subtracts defense, averages in crits, and multiplies by attacks per second to give effective damage per second. FAQ: Q: How does Terraria turn use time into attack speed? A: Terraria runs at sixty ticks per second, and use time is measured in ticks. Attacks per second is therefore sixty divided by the use time, so a weapon with a use time of twenty fires three times a second. Lower use time means faster swings and higher DPS. Q: How is defense applied to damage? A: Enemy defense reduces each hit by a fraction of the defense value that depends on difficulty: half on Normal, three-quarters on Expert, and the full amount on Master. The damage after reduction is floored at one, so even heavily armored enemies always take at least one point per hit. Q: How do critical hits factor into DPS? A: Critical hits deal double damage in Terraria. The calculator averages this in by multiplying the post-defense damage by one plus the crit chance, so a fifty percent crit chance raises average per-hit damage by fifty percent rather than guaranteeing every other hit. Q: What is the difference between percent and flat bonuses? A: Percent bonuses scale the weapon's base damage, while flat bonuses add a fixed amount on top. The tool applies the percent multiplier first, then adds flat damage, matching how Terraria stacks damage-class percentages with flat accessory bonuses. Q: Why does hit rate matter? A: Not every swing connects, especially with projectiles or fast-moving targets. The hit-rate input scales effective attacks per second so your DPS reflects shots that actually land, giving a more realistic number than assuming perfect accuracy. #### Warhammer Age of Sigmar Points Calculator URL: https://geratools.com/warhammer-age-of-sigmar-points Add Age of Sigmar units, mark reinforced units, and tally your army total against 1000, 2000, and 2500-point matched-play limits. Build legal AoS lists in seconds with a live points budget check. How to use: 1. Choose your game size: Pick 1000, 2000, or 2500 points to set the budget the tool checks your list against. 2. Add units: Enter each unit's name and base points. Tick reinforced to double a unit's points and model count. 3. Read the total: The running tally shows points used and remaining, turning red if you exceed the limit. FAQ: Q: What is a standard Age of Sigmar game size? A: Standard matched play is 2000 points. Smaller games are often played at 1000 points and larger ones at 2500, which are the three options in the tool. Q: How does reinforcing a unit affect points? A: A reinforced unit has double the models and costs double its base points. Ticking the reinforced box multiplies that unit's points by two in the total, exactly as the matched-play rules require. Q: Do enhancements cost points in AoS? A: In current Age of Sigmar, artefacts, spells, and other enhancements generally cost no points but are limited in number. The tool totals unit points, so add any pack-specific point costs only if your rules pack assigns them. Q: Which edition does this follow? A: It uses the standard 1000/2000/2500-point matched-play structure and the reinforced-unit doubling rule. Always take individual unit costs from your faction's current points list, since they change with updates. Q: Is my list private? A: Yes. The calculator runs entirely in your browser and never sends your list anywhere. #### Dice Notation Roller URL: https://geratools.com/dice-notation-roller A powerful browser dice roller that understands standard tabletop notation — multiple dice groups, modifiers, advantage/disadvantage, keep/drop highest or lowest, and exploding dice. Per-die breakdown, persistent roll history, statistics and CSV export. 100% client-side. How to use: 1. Type your dice notation: Enter an expression such as 3d6+2 or 2d20kh1+5. Combine groups with + and -, and add a flat modifier like +3. 2. Add keep, drop or exploding rules: Use kh/kl to keep the highest or lowest dice, dh/dl to drop them, and ! to make a die explode on its maximum face. 3. Roll and read the breakdown: Press Roll. Each die is shown individually, dropped dice are struck through, and natural max/min faces are highlighted. 4. Reuse and track: Save common rolls, reroll any past roll from the history list, and export your whole session to CSV for analysis. FAQ: Q: What dice notation does this roller support? A: It supports standard tabletop notation: NdM for N dice of M sides (for example 3d6), flat modifiers (+2 or -1), multiple groups joined with + and - (such as 1d8+3d6+4), keep/drop directives (kh, kl, dh, dl) and exploding dice with a trailing exclamation mark (3d10!). You can also list several independent expressions separated by commas. Q: How do advantage and disadvantage work? A: Advantage in Dungeons and Dragons means rolling two d20s and taking the higher — written 2d20kh1 (keep highest 1). Disadvantage takes the lower — 2d20kl1 (keep lowest 1). The tool rolls both dice, shows them, and strikes through the one that was dropped so you can see exactly what happened. Q: What does kh, kl, dh and dl mean? A: These are keep/drop directives. kh-N keeps the N highest dice, kl-N keeps the N lowest, dh-N drops the N highest and dl-N drops the N lowest. For example 4d6dl1 rolls four six-sided dice and drops the lowest — the classic Dungeons and Dragons ability-score method. Q: What are exploding dice? A: Adding an exclamation mark (for example 3d10!) makes a die explode: whenever it rolls its maximum face you roll it again and add the new result, repeating until you roll something below the maximum. Exploding dice are common in systems like Savage Worlds and Shadowrun. The roller caps explosions for safety and ignores them when estimating the average. Q: Are the rolls genuinely random? A: Yes. The roller uses the browser Web Crypto API (crypto.getRandomValues) with rejection sampling, so every face is equally likely and there is no modulo bias. This is the same source of randomness browsers use for cryptographic keys — far better than a typical Math.random shuffle. Q: Is my roll history private, and can I export it? A: Completely private. Every roll is computed and stored in your own browser using localStorage; nothing is ever sent to a server. You can export your entire session to a CSV file (timestamp, label, notation and total) for spreadsheets or play-by-post logs, and clear the history at any time. #### D&D Ability Score Calculator URL: https://geratools.com/dnd-ability-score-calculator A complete D&D 5e ability score calculator covering Standard Array, Point Buy, 4d6-drop-lowest rolling, and manual entry. Shows ability modifiers, saving throw bonuses, proficiency bonus by level, and encounter XP thresholds. Runs entirely in your browser. How to use: 1. Choose a generation method: Pick Standard Array, Point Buy, Dice Roll, or Manual to set your six ability scores. 2. Assign or adjust your scores: In Standard Array mode, use the dropdowns to assign each value. In Point Buy, use the + / - buttons within the 27-point budget. In Dice Roll, click "Roll 4d6 Drop Lowest" to generate a new set. In Manual, type any value from 1 to 30. 3. Set your character level: Enter your level (1-20) to see the correct proficiency bonus and encounter XP thresholds for that tier. 4. Toggle saving throw proficiencies: Click the circular P button next to each ability to mark it as a saving throw proficiency. The save column updates instantly. 5. Copy your stat block: Use the Copy Summary button to place your full ability score block on the clipboard for use in a character sheet or virtual tabletop. FAQ: Q: How is the ability modifier calculated? A: The modifier is floor((score - 10) / 2). So a score of 16 gives (16-10)/2 = +3, a score of 8 gives (8-10)/2 = -1, and a score of 10 or 11 gives +0. This formula comes directly from the D&D 5e Player's Handbook (PHB p.13). Q: What is the Standard Array? A: The Standard Array is the set of values (15, 14, 13, 12, 10, 8) provided in the PHB as a balanced, quick-assign method. You assign each number to one ability. No score can be assigned twice. Q: How does Point Buy work? A: You start with 27 points and all six abilities at 8. Each increase costs 1 point up to 13; raising to 14 costs 7 points total (2 extra) and 15 costs 9 points total (2 more again). The non-linear cost makes very high scores expensive, encouraging a more balanced character. Q: What is 4d6 drop lowest? A: You roll four six-sided dice, discard the lowest result, and sum the remaining three. Repeated six times, this gives one score per ability. The expected average per roll is approximately 12.2, slightly higher than Standard Array, with more variance. Q: What is the proficiency bonus and how does it grow? A: The proficiency bonus starts at +2 at level 1 and increases by +1 every four levels: +2 at levels 1-4, +3 at levels 5-8, +4 at levels 9-12, +5 at levels 13-16, and +6 at levels 17-20. It applies to attack rolls, saving throws, and skill checks where you are proficient. Q: What are the XP encounter thresholds? A: The DMG (p.82) defines four difficulty tiers per character level. Easy, Medium, Hard, and Deadly. Multiply the shown threshold by your party size to get the total XP budget for that difficulty. A Deadly encounter risks character death; Easy encounters rarely drain resources. #### Damage Per Second (DPS) Calculator URL: https://geratools.com/damage-per-second-calculator Free DPS calculator for games. Enter base damage, attack speed, crit chance, crit multiplier, bonus damage and skill cooldowns to get your exact effective DPS. Works for ARPGs, MMORPGs, shooters and tabletop systems. 100% in-browser. How to use: 1. Choose a weapon preset or enter custom stats: Pick a preset like Fast Dagger or Greatsword to auto-fill typical values, or type your own base damage and attacks per second. 2. Set crit chance and crit multiplier: Enter your critical-hit chance in percent and the crit multiplier. A 200% multiplier means crits deal double damage. 3. Add bonus damage: Enter any flat percentage bonus from buffs, passive skills or gear. This scales the entire hit before crits are applied. 4. Add skills or abilities (optional): Click Add Skill and enter each ability name, damage, cooldown and cast time to include skill DPS in the total. 5. Read the effective DPS: The calculator shows average hit damage, auto-attack DPS, skill DPS and the combined effective DPS accounting for time spent casting. FAQ: Q: What is the DPS formula used here? A: Average hit = BaseDmg * (1 + BonusPct/100) * (1 + CritChance/100 * (CritMult/100 - 1)). Auto DPS = AvgHit * AttacksPerSecond. Skill DPS = sum of each skill damage divided by (cooldown + cast time). Effective DPS = AutoDPS * (1 - castingFraction) + SkillDPS, where castingFraction is the fraction of time locked in cast animations. Q: What does crit multiplier mean? A: Crit multiplier is the total damage dealt on a critical hit expressed as a percentage of a normal hit. A value of 200% means a crit deals twice the normal damage. Some games call this "crit damage" or "crit bonus". If your game adds 150% on top of the base hit, enter 250% here (100% base + 150% bonus). Q: How does the skill rotation interact with auto-attacks? A: When you cast a skill, you cannot auto-attack during the cast time. The calculator estimates the fraction of time spent casting across all skill cooldowns (sum of castTime / cooldown for each skill, clamped at 100%) and reduces auto-attack DPS proportionally. Skills with no cast time (instant casts) do not reduce auto-attack uptime. Q: Why is effective DPS lower than my auto-attack DPS alone? A: This happens when skills have long cast times relative to their cooldown. A skill with a 2-second cast on a 4-second cooldown occupies 50% of your time casting, halving auto-attack output. If the skill DPS gained exceeds the auto-attack DPS lost, it is still worth using. Q: Does this calculator support DoT (damage over time) effects? A: Treat each DoT tick as an ability with damage equal to the total DoT damage and cooldown equal to the DoT duration. For example, a bleed that deals 300 damage over 6 seconds has an effective DPS contribution of 300 / 6 = 50 DPS regardless of how many ticks there are. Q: How do I model dual-wielding or multi-hit abilities? A: For dual wield, set attacks per second to the combined hit rate of both weapons and base damage to the average hit. For an ability that hits 3 times, multiply the per-hit damage by 3 in the skill damage field, keeping the cooldown as normal. #### Experience Points (XP) Calculator URL: https://geratools.com/experience-points-calculator Free D&D 5e experience points calculator. Set your party size and level, add monster groups by Challenge Rating, and instantly see the adjusted XP, difficulty rating (Easy/Medium/Hard/Deadly) and XP per player. Includes a full level-up XP table and a session XP tracker with level-up detection. How to use: 1. Set your party: Enter the number of characters and their average level. The calculator looks up the official PHB XP thresholds for that level and multiplies them by party size. 2. Add monster groups: Click "Add monster group", pick a Challenge Rating from the dropdown, and enter how many creatures of that CR are in the fight. 3. Read the difficulty: The adjusted XP (raw XP times the multi-monster multiplier) is compared against the party thresholds to give an Easy/Medium/Hard/Deadly rating. 4. Check the level-up table: Switch to the "Level-Up XP" tab for the complete PHB level progression and per-character encounter thresholds for every level. 5. Track session XP: Switch to "XP Tracker", enter your character current total XP and the XP earned this session to see your new level and progress bar. FAQ: Q: How does D&D 5e calculate encounter difficulty? A: The Dungeon Master's Guide uses a two-step process. First, total the raw XP of all monsters. Second, apply a multiplier based on the number of monsters: 1 monster = ×1, 2 = ×1.5, 3–6 = ×2, 7–10 = ×2.5, 11–14 = ×3, 15+ = ×4. The resulting adjusted XP is compared against the party's combined threshold (per-character threshold × number of characters) to determine Easy, Medium, Hard, or Deadly difficulty. Q: Does the multiplier affect how much XP characters actually earn? A: No. The multiplier is only used to assess difficulty. Characters always earn the raw (un-multiplied) XP, split equally among the party. This calculator shows both numbers clearly. Q: What happens if my party is smaller or larger than four people? A: For parties of fewer than 3 characters, the calculator moves the multiplier up one bracket (making the encounter harder relative to the numbers). For 6 or more characters, it moves the bracket down. This matches the DMG guidance on party-size adjustments. Q: How much XP does a CR 5 creature give? A: A Challenge Rating 5 creature is worth 1,800 XP according to the DMG XP-by-CR table (p. 274). The calculator includes all CRs from 0 through 30, including fractional CRs (1/8, 1/4, 1/2). Q: How many XP do I need to reach Level 5? A: You need a total of 6,500 XP to reach Level 5 in D&D 5e. Going from Level 4 to Level 5 costs 3,800 XP on top of the 2,700 XP already banked at Level 4. The Level-Up XP tab shows every level in a scrollable table. Q: Is this calculator official or homebrew? A: All XP values, encounter thresholds, and level-up milestones come directly from the D&D 5th Edition Player''s Handbook (level-up table, p. 15; encounter thresholds, p. 82) and the Dungeon Master''s Guide (XP by CR, p. 274; encounter multipliers, p. 82). No homebrew modifications are applied. #### Loot Roll Generator URL: https://geratools.com/loot-roll-generator A fully client-side RPG loot roll simulator. Build custom weighted loot tables with rarity tiers, drop-chance filtering, and NdM+K quantity notation — then roll single or batch drops instantly in your browser. How to use: 1. Choose a preset or customise your table: Pick from Dungeon Chest, Goblin Pockets, Dragon Hoard, or start from the Default table. Switch to the Edit Table tab to add, remove, or tweak any item. 2. Set weights, drop chances, and quantities: Each item has a relative weight (higher = more likely to be selected), a drop-chance percentage (the d100 check after selection), and a qty field supporting dice notation like 2d6+1. 3. Roll loot in batches: Set how many rolls per batch and how many batches, then hit Roll Loot. Results show awarded items, quantities, and the raw drop rolls. Failed drops are listed in a collapsible section. 4. Inspect effective drop chances: Open the Drop Chances tab to see the combined probability for every item, sorted from most to least common. This lets you balance the table before running a session. FAQ: Q: How does the weighted random selection work? A: Each item has a numeric weight. The generator sums all weights to get W, then picks a random number u in [0, W). It walks the item list, subtracting each weight from u, and awards the item where u first reaches zero or below. An item with weight 40 in a table summing to 100 will be selected 40% of the time — regardless of how many other items exist. Q: What is the difference between Weight and Drop%? A: Weight controls which item is selected from the table on each roll. Drop% is a second independent check — once the item is selected, the generator rolls d100 and only awards the item if the result is less than or equal to the drop threshold. You can therefore model "rare items that sometimes miss even when targeted" by giving them a high weight but a low drop%.' Q: What dice notation can I use in the Qty field? A: The Qty field accepts a plain integer (e.g. 5), standard dice notation (e.g. 2d6), and notation with a flat bonus or penalty (e.g. 3d4+2 or 1d8-1). The minimum awarded quantity is always 1. The expected value shown in the Drop Chances tab is N*(M+1)/2 + K for NdM+K. Q: How is effective drop chance calculated? A: Effective% = (item weight / total weight) x (drop% / 100) x 100. For example, an item with weight 5 in a 100-weight table and a 40% drop chance has an effective probability of 5% x 40% = 2% per roll. The Drop Chances tab shows this for every item so you can see at a glance how skewed your table is toward common items. Q: Can I save my custom loot table? A: All edits are held in the page state. The tool is 100% client-side and does not upload or store any data, so refreshing the page will reset to the default table. If you want to preserve a custom table between sessions, copy the resulting roll output or note the weights manually. Q: How many rolls can I run at once? A: Up to 100 rolls per batch and 20 batches simultaneously (2,000 individual rolls in one click). Results are appended to the history so you can compare multiple batches. The history is capped at the 50 most recent batches to keep the page responsive. #### MTG Life Counter URL: https://geratools.com/mtg-life-counter Free browser-based MTG life counter for 2–6 players. Tracks life totals, poison counters (10 = eliminated), commander damage (21 = eliminated), energy, experience, undo history, and auto-detects the winner. Works offline — nothing is uploaded. How to use: 1. Choose your format: Select 2–6 players and a starting life total (20 for Standard/Modern/Draft, 40 for Commander/EDH, 25 for some Brawl variants) and press Start game. 2. Adjust life totals: Use the +1, -1, +5, -5 buttons for quick changes. Type a number in the text field and press Set to jump directly to that total, or press the ± button to apply it as a delta. 3. Track poison counters: Press + on the poison row each time a player receives a poison counter. At 10 poison counters the player is automatically marked as eliminated — no manual check needed. 4. Track commander damage: Enable the Commander damage checkbox (on by default). Each player card shows how much damage they have taken from each opponent's commander. Reaching 21 from any single commander eliminates the player. 5. Use undo: Press the Undo button to reverse the most recent change — useful when a mis-click happens mid-game. 6. View change history: Press the History button to open a timestamped sidebar showing every life, poison, energy, experience, and commander-damage change made during the session. FAQ: Q: What are the starting life totals for each MTG format? A: Standard, Modern, Pioneer, and Limited all start at 20 life. Commander (EDH) and Oathbreaker start at 40 life. Brawl and Historic Brawl are typically 25 life. Tiny Leaders uses 25. Two-Headed Giant teams share a combined 30-life pool. This counter supports 20, 25, 30, and 40 as preset options — choose the one matching your format. Q: How does the poison counter elimination rule work? A: A player who has accumulated 10 or more poison counters loses the game immediately, regardless of their life total. Infect and Wither are the primary keyword mechanics that deal damage in the form of poison counters to players (and -1/-1 counters to creatures). This counter marks a player as eliminated the moment their poison count reaches 10 and shows the reason on their card. Q: What is the commander damage rule? A: In Commander (EDH), a player who has been dealt 21 or more combat damage by a single commander over the course of the game loses — even if that commander changed zones or was re-cast. The damage is cumulative per commander, not per combat. This counter tracks damage received from each opponent independently, so you can have Player 2 take 12 from Commander A and 15 from Commander B and each is tracked separately. Q: Can I rename players mid-game? A: Yes. Click any player name to open an inline text field. Press Enter or click away to confirm. The new name appears immediately in all references, including the history sidebar and commander damage labels. Q: Does undoing a change affect the elimination status? A: Yes. If a player was marked eliminated and you undo the change that caused the elimination (for example a mis-click that brought life to 0) the eliminated badge disappears and the player is considered active again. The counter always re-evaluates status from the current values, not from a cached state. Q: Does this work offline or on mobile? A: Fully. The tool runs entirely in your browser — no server calls, no account required. It works offline once the page is loaded, making it suitable for paper Magic sessions at a kitchen table or local game store where network connectivity is unreliable. Reload the page to start a fresh session. ### School & Study #### A-Level Grade Boundary Checker URL: https://geratools.com/a-level-grade-boundary-checker Enter your raw exam mark and total marks, then select your board to see the approximate grade boundary for A*, A, B, C, D or E using representative recent AQA, Edexcel and OCR boundary data. How to use: 1. Pick your board: Choose AQA, Edexcel or OCR so the checker uses representative boundary percentages for that board. 2. Enter your marks: Type the raw mark you scored and the total marks available on the paper or across the qualification. 3. Read your estimated grade: The tool converts your mark to a percentage, places it in a grade band and shows how many more marks the next grade up needs. FAQ: Q: Are these the exact grade boundaries? A: No. Real boundaries are released by each board every summer and shift with how hard the papers were. This checker uses representative recent percentages so you get a realistic estimate, not an official result. Q: Why do boundaries change every year? A: Boards set boundaries after marking so that a given grade reflects the same standard despite differences in paper difficulty. A harder paper lowers the boundary, an easier one raises it, which is why fixed percentages are only a guide. Q: How is my grade worked out here? A: The tool turns your raw mark into a percentage of the total, then checks it against the board's typical boundary percentages for A* down to E. The highest band your percentage clears becomes your estimated grade. Q: Why do A-Levels use uniform marks? A: Linear A-Levels combine several papers, and boards often convert raw marks to a uniform mark scale before applying boundaries. For a quick estimate you can enter your combined raw total against the combined maximum and read the band. Q: Can I trust this for results day predictions? A: Use it for a rough self-check only. Until your board publishes the actual boundaries for your series, no tool can tell you the precise grade, especially near a boundary where a mark or two decides the outcome. #### A-Level UCAS Tariff Points Calculator URL: https://geratools.com/a-level-ucas-tariff-calculator Enter your A-Level subjects and grades (A*, A, B, C, D or E) to compute the total UCAS tariff points, and check against the typical offer conditions for UK university courses. How to use: 1. Add your subjects: For each A-Level or AS-Level, choose the qualification type and the grade you achieved or expect. Use the add button for more rows. 2. Let it total the points: The calculator applies the official UCAS tariff to each grade and adds them up as you change them. 3. Compare to an offer: Read the typical offer band shown beneath your total and check it against the requirements for your chosen course. FAQ: Q: How many UCAS points is each A-Level grade worth? A: On the current UCAS tariff an A-Level A* is 56 points, A is 48, B is 40, C is 32, D is 24 and E is 16. AS-Levels are worth 40 percent of the A-Level value, so an AS A is 20 points down to 6 for an E. Q: How many points is AAB worth? A: Three A-Levels at A, A and B total 48 plus 48 plus 40, which is 136 UCAS tariff points. This is a common offer level for many competitive courses below the very top tier. Q: Do AS-Levels count if I also took the full A-Level? A: No. If you continued a subject to full A-Level, you only count the A-Level grade, not the AS result for the same subject. Count standalone AS-Levels you did not take further as separate rows. Q: What tariff do I need for a typical university offer? A: Offers vary widely. AAA is 144 points, ABB is 128, BBC is 112 and CCC is 96. The tool shows which band your total reaches, but always check the exact requirement for the specific course. Q: Does the UCAS tariff include the EPQ? A: The Extended Project Qualification carries its own tariff, with an A* worth 28 points down to E. This calculator focuses on A-Levels and AS-Levels, so add EPQ points separately if your offer counts them. #### AP Exam Score Guide (1-5 Scale) URL: https://geratools.com/ap-exam-score-guide Select an AP subject to see the typical score distribution (percent scoring 1-5), the minimum score most colleges accept for credit (usually 3-4), and estimated credit hours granted. How to use: 1. Select an AP subject: Choose the AP exam you took or plan to take from the list. 2. Read the score distribution: See the approximate percentage of students earning each score from 1 to 5. 3. Check credit policy: Review the minimum score most colleges accept and estimated credit hours. FAQ: Q: How is the AP exam scored? A: AP exams are scored on a 1–5 scale, where 5 is 'extremely well qualified' and 1 is 'no recommendation.' The score combines multiple-choice and free-response sections, equated each year by the College Board. Q: What AP score do colleges accept for credit? A: Most colleges grant credit for a 3 or higher, but selective universities often require a 4 or 5. Policies vary by school and subject, so always confirm with the specific college's AP credit chart. Q: How many credit hours does an AP exam give? A: A qualifying AP score typically grants 3–8 college credit hours depending on the subject and whether it covers one or two semesters. Year-long sequences like AP Calculus BC or AP Physics C can award more. Q: Are the score distributions exact? A: They are close approximations of recently published College Board distributions, which shift slightly each year. Use them to gauge difficulty, not as official current-year figures. Q: Does a higher AP score save money? A: Yes — earning credit lets you skip introductory courses, reducing the number of paid college credit hours you need to graduate and potentially shortening time to degree. #### College Major GPA Benchmark Calculator URL: https://geratools.com/college-major-gpa-benchmark Enter your GPA and major to see how you compare to the typical average GPA by field of study (STEM vs Humanities vs Social Sciences vs Business) — useful context for grad school applications. How to use: 1. Enter your GPA: Type your cumulative GPA on the 4.0 scale. 2. Select your major field: Choose the broad field that best matches your major, since average GPAs differ between STEM, business, social science, and the humanities. 3. Read your standing: The tool shows the typical average for your field, your difference from it, and whether you are above or below the benchmark. FAQ: Q: Why do average GPAs differ by major? A: Grading norms vary by field. Education and humanities majors tend to have higher average GPAs, while engineering, math, and the physical sciences grade more strictly, so the same effort can produce a lower GPA in STEM fields. Q: What are typical average GPAs by field? A: Broadly, education and humanities average around 3.3 to 3.4, social sciences and business around 3.1 to 3.2, and STEM fields like engineering and the natural sciences around 2.9 to 3.1. These are approximate national patterns, not exact figures. Q: How should grad schools read my GPA? A: Admissions committees know that a 3.2 in engineering reflects different rigor than a 3.6 in a softer-graded field. Presenting your GPA next to your field's average gives useful context, especially for borderline applications. Q: Are these benchmarks official? A: No. They are approximate averages drawn from widely reported studies of grade distributions by discipline. Your own institution's averages may differ, and individual programs vary considerably. Q: Does a below-average GPA hurt grad school chances? A: Not necessarily. Committees weigh course rigor, trend over time, research, recommendations, and test scores. A GPA slightly below your demanding field's average, with an upward trend and strong other factors, can still be competitive. #### CPA Exam Section Score Calculator URL: https://geratools.com/cpa-exam-score-calculator Enter your CPA exam section scores across FAR, AUD, REG and the 2024 discipline sections (BAR, ISC, TCP) to see pass/fail status. The passing score on every section is 75 on a 0-99 scale. How to use: 1. Pick your section: Choose the CPA section you sat — the three core sections (FAR, AUD, REG) or a 2024 discipline section (BAR, ISC, TCP). 2. Enter the reported score: Type the scaled score the AICPA reported, between 0 and 99. 3. Read the result: The tool flags pass (75 or higher) or fail and shows how far you are from the cutoff. FAQ: Q: What is the CPA exam passing score? A: The passing score on every CPA exam section is 75 on a 0-99 scale. This is not a percentage or a percentile — it is a scaled score that weights both correct answers and the difficulty of the questions you received. Q: Are the CPA sections different after 2024? A: Yes. Under the CPA Evolution model effective 2024 you take three core sections (FAR, AUD, REG) plus one discipline section of your choice: BAR (Business Analysis and Reporting), ISC (Information Systems and Control) or TCP (Tax Compliance and Planning). BEC was retired. Q: Is the CPA score a percentage of questions right? A: No. The scaled score blends your multiple-choice and task-based simulation performance, adjusted for question difficulty. You can answer the same fraction correctly as another candidate and receive a different scaled score depending on which questions you saw. Q: How long do passing CPA sections stay valid? A: Most jurisdictions use an 18-to-30-month rolling window from the date you pass your first section. NASBA's model rule extended the window to 30 months, but you should confirm your state board's exact policy. Q: Does a 74 round up to a pass? A: No. A reported 74 is a failing score; there is no rounding at the cutoff. The score you see has already been scaled and rounded to a whole number, so 74 means you must retake that section. Q: How soon can I retake a failed CPA section? A: Under continuous testing there are no quarterly blackout windows: once your score is released, you can apply for a new Notice to Schedule and book the next available seat. The practical wait is score-release timing plus NTS processing, not a fixed testing window. #### ECTS Student Workload Calculator URL: https://geratools.com/ects-workload-calculator Enter your total ECTS credits to compute the expected student workload in hours at 25-30 hours per credit, helping you plan course load, part-time study schedules, and realistic weekly study commitments. How to use: 1. Enter your ECTS credits: Type the total ECTS credits for your module, semester, or year. 2. Set hours per credit: Choose 25, 27, or 30 hours per ECTS credit depending on your country's convention. 3. Read your workload: The calculator multiplies credits by the rate to give total and weekly hours. FAQ: Q: How many hours is one ECTS credit? A: One ECTS credit represents 25 to 30 hours of total student workload, including lectures, seminars, private study, and assessment. Most countries use 25-30; 25 is common in much of Europe. Q: How many hours is a full ECTS year? A: A full academic year is 60 ECTS. At 25 hours per credit that is 1500 hours, and at 30 hours per credit it is 1800 hours of total workload for the year. Q: Does workload include lectures or just self-study? A: ECTS workload is the total time expected, covering contact hours (lectures, labs, seminars) plus independent study and assessment. It is not only self-study. Q: How do I convert workload to weekly hours? A: Divide the total workload by the number of study weeks. This calculator can split the total across a number of weeks you enter to estimate a sustainable weekly commitment. Q: Which hours-per-credit rate should I use? A: Use the rate published by your institution or national framework. The tool offers 25, 27, and 30 so you can see the range; the official figure varies by country. Q: How do ECTS credits convert to UK CATS or US credit hours? A: The standard UK mapping is 2 CATS = 1 ECTS (120 CATS = 60 ECTS per year). For the US there is no official equivalence, but admissions offices commonly treat 60 ECTS as about 30 semester credit hours — roughly 2 ECTS per US credit. For transfer applications, always use the receiving university's own published conversion table. #### Exam Grade Distribution Calculator URL: https://geratools.com/exam-grade-distribution-calculator Paste a list of raw exam scores to compute the class mean and standard deviation, then generate suggested A-F letter-grade cutoffs on a normal curve and see how many students land in each grade band. How to use: 1. Paste the scores: Enter every student's raw exam score, separated by commas, spaces or new lines. 2. Choose the curve center: Set which letter grade the class mean should map to (typically C or B-) to control how generous the curve is. 3. Read the distribution: The tool shows the mean, standard deviation, suggested cutoffs and a count of students in each grade band. FAQ: Q: How are the curved cutoffs calculated? A: The tool computes the class mean and standard deviation, then places letter-grade boundaries at fixed multiples of the SD around the mean. By default the mean sits at the C band, with each higher grade one half standard deviation above and lower grades below, so grades reflect relative standing. Q: What is standard deviation here? A: Standard deviation measures how spread out the scores are. A small SD means most students scored close to the mean, so grade bands are narrow; a large SD means scores are widely spread, producing wider bands. The tool uses the population standard deviation of the entered scores. Q: Should I always grade on a curve? A: No. Curving is appropriate when an exam was unusually hard or you want grades to reflect relative rank. For mastery-based courses, absolute cutoffs (90=A, 80=B) are fairer. Use this tool when relative standing is what you want to reward. Q: Why does the mean map to C by default? A: Mapping the mean to C produces a roughly symmetric distribution where the average student earns an average grade. You can shift the center to B- for a more generous curve; that raises every cutoff and moves more students into higher bands. Q: Does the calculator handle duplicate or zero scores? A: Yes. Every numeric value you enter is counted, including zeros and repeats. Non-numeric tokens are ignored. The mean and SD reflect all valid scores, so leave out entries you do not want to influence the curve. #### Exam Mark Scheme Grade Calculator URL: https://geratools.com/exam-mark-scheme-calculator Enter the total marks available and grade boundary thresholds as absolute marks to classify any raw score into its corresponding grade — useful for teachers and students using GCSE or A-Level mark schemes. How to use: 1. Enter the total marks: Type the maximum marks available on the paper so percentages can be derived. 2. Set the grade boundaries: Enter the minimum raw mark required for each grade, highest grade first. 3. Enter the raw score: Type the student's achieved mark to see the awarded grade and percentage. FAQ: Q: What are grade boundaries? A: Grade boundaries are the minimum raw marks needed to achieve each grade on a given exam. They are set by the exam board after marking and vary by paper difficulty, so the same percentage can earn different grades across sessions. Q: How is the grade decided from a raw mark? A: The calculator compares your raw mark against each boundary from highest to lowest and awards the first grade whose threshold you meet or exceed. If you fall below every boundary, the lowest grade or U (ungraded) is assigned. Q: Why use absolute marks instead of percentages? A: Official GCSE and A-Level mark schemes publish boundaries as absolute raw marks rather than percentages, because uniform mark conversions differ between papers. Using raw marks matches the published mark scheme exactly. Q: Can I use this for any exam board? A: Yes. The boundaries are fully editable, so you can paste the published thresholds from AQA, Edexcel, OCR, WJEC, or any school's internal mark scheme. The grade labels are also editable. Q: Does it round the percentage? A: The percentage is shown to one decimal place for clarity. Grading itself never uses the rounded percentage — it always uses your raw mark against the raw-mark boundaries to avoid rounding errors at the edges. #### Extra Credit GPA Impact Calculator URL: https://geratools.com/extra-credit-gpa-impact-calculator Enter your current weighted score, course total points, extra credit points available, and final grade weighting to see exactly how much extra credit can move your final letter grade in a course. How to use: 1. Enter your current points: Add the points you have earned so far and the total points possible in the course before extra credit. 2. Add extra credit: Enter the number of extra credit points available to you. 3. Read the impact: The tool shows your grade before and after extra credit, the percentage gain, and the new letter grade on a standard scale. FAQ: Q: How does extra credit change my grade? A: Extra credit is added on top of your earned points without increasing the total possible points: newPercent = (earned + extraCredit) / totalPossible × 100. This is why even a few extra points can lift your percentage measurably. Q: Why doesn't the denominator increase? A: Most instructors design extra credit as a bonus, not an extra assignment, so it raises your numerator while the total stays fixed. If your course adds extra credit to the denominator instead, the boost is smaller — check your syllabus. Q: What letter grade scale is used? A: The tool uses the common US scale: A 90+, B 80-89, C 70-79, D 60-69, F below 60. It reports both your numeric percentage and the corresponding letter so you can see whether extra credit crosses a threshold. Q: Can extra credit push me over 100%? A: Yes, mathematically. If earned plus extra credit exceeds the total possible, your percentage can exceed 100%. The tool shows the raw figure so you can see the cushion, though most gradebooks cap the displayed grade at 100%. Q: How much extra credit do I need for the next letter? A: The tool reports the gap to the next letter grade in points, so you can see exactly how many extra credit points would lift you from, say, a B to an A. #### Brazilian Grade Converter (0-10 Scale) URL: https://geratools.com/gpa-brazil-converter Enter grades on the Brazilian 0-10 scale (typical pass mark 5.0 or 6.0 depending on institution) to compute the US 4.0 GPA equivalent and ECTS grade for each course. How to use: 1. Set your pass mark: Choose whether your institution passes at 5.0 or 6.0 so borderline grades convert correctly. 2. Add each course: Enter a course name, your 0-10 grade (nota), and the course's credit hours or workload. 3. Read your GPA: The tool shows each course's US 4.0 equivalent and a credit-weighted overall GPA. FAQ: Q: How does the Brazilian 0-10 scale map to a US GPA? A: There is no single official table, but a common linear mapping treats 10-9 as 4.0 (A), 8.x as 3.5, 7.x as 3.0 (B), 6.x as 2.5, the pass mark to 5.9 as 2.0 (C), and anything below the pass mark as 0.0 (F). This tool uses a piecewise mapping anchored to your chosen pass mark. Q: Should I use a pass mark of 5.0 or 6.0? A: It depends on your university. Many federal universities pass at 6.0 (or 7.0), while some private institutions pass at 5.0. Choose the value printed in your academic regulations so failing grades convert to 0.0 correctly. Q: What does nota mean? A: Nota is Portuguese for grade or mark. Brazilian transcripts list each course's nota on a 0 to 10 continuous scale, often to one decimal place. Q: Why is the conversion only an estimate? A: Different US institutions use different equivalence tables, and a continuous 0-10 scale does not map cleanly onto discrete US letter grades. Use the result for planning and confirm the official method with your target university or an evaluation service like WES. Q: Is my data uploaded? A: No. All calculations run in your browser; nothing is sent anywhere or stored. #### Exam Time Per Question Calculator URL: https://geratools.com/exam-time-per-question Work out how long to spend per question in an exam from the time limit, question count and a review reserve, plus a halfway checkpoint. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter the exam length: Type the total exam time in minutes and the number of questions. 2. Add a review reserve: Set minutes to hold back for checking answers, for example 10 minutes. 3. Read your pace: The time to spend per question and a halfway checkpoint appear instantly. FAQ: Q: How is time per question worked out? A: It takes the exam length minus your review reserve, then divides the remaining working minutes by the number of questions. Q: Why reserve time for review? A: Holding back a few minutes lets you re-check answers and finish any flagged questions, so the per-question pace is based only on the working time that remains. Q: Is anything sent to a server? A: No. The calculation runs entirely in your browser and nothing is uploaded. Q: How many minutes per question for a 120-minute exam with 50 questions? A: Reserving 10 minutes for review leaves 110 working minutes. 110 ÷ 50 ≈ 2.2 minutes (about 132 seconds) per question. Q: How much time should I reserve for review? A: A common rule is 5 to 10 percent of the total, or enough to revisit flagged questions. The calculator subtracts your reserve before working out the pace, so the per-question figure already leaves room to check answers. Q: What is the halfway checkpoint for? A: It tells you how many minutes should have elapsed when you reach the midpoint of the questions. If the clock is past that figure you are behind pace and should speed up; if not, you are on track. Q: Should I spend equal time on every question? A: The per-question figure is an average target, not a hard limit. Move faster through easy questions to bank time for harder ones, but use the average as a signal to move on if a single question is eating too much time. ### Crypto & DeFi #### Bicarbonate Deficit Calculator URL: https://geratools.com/bicarbonate-deficit-calculator Calculates the bicarbonate deficit in mmol from target HCO₃, measured HCO₃, and body weight using the standard 0.4 to 0.5 distribution-volume formula to guide IV sodium bicarbonate replacement in severe metabolic acidosis. Used in nephrology and emergency medicine. Runs in your browser. How to use: 1. Enter the bicarbonate values and weight: Provide the target HCO₃, the measured HCO₃ in mmol/L, and the patient's weight in kilograms. 2. Choose the distribution factor: Select the bicarbonate space (0.4 to 0.5 of body weight); a higher value is used in severe acidosis where the apparent space expands. 3. Read the deficit: The deficit in mmol is the distribution volume times the difference between target and measured HCO₃, guiding the replacement dose. FAQ: Q: What is the bicarbonate deficit formula? A: The deficit in mmol equals the distribution factor times body weight in kilograms times the difference between target and measured bicarbonate. A common form is 0.5 × weight × (target HCO₃ − measured HCO₃), with the factor representing the apparent bicarbonate space. Q: Why does the distribution factor vary from 0.4 to 0.5? A: The apparent volume of bicarbonate distribution is not fixed. In mild acidosis about 0.4 to 0.5 of body weight is used, but in severe acidosis the apparent space expands, so a higher factor (up to 0.8 in extreme cases) better reflects the buffering across cells and bone. Q: Should the full deficit be replaced at once? A: No. It is usual to give only part of the calculated deficit, often half, then recheck the blood gas and recalculate. Rapid full correction risks overshoot, hypokalaemia, hypocalcaemia, sodium and volume overload, and paradoxical CSF acidosis. Q: When is bicarbonate replacement appropriate? A: IV sodium bicarbonate is generally reserved for severe metabolic acidosis, typically a pH below about 7.1 to 7.2, especially with normal-anion-gap (loss) acidosis such as renal tubular acidosis or diarrhoea. In lactic and ketoacidosis, treating the cause is usually preferred. Q: Is my data stored anywhere? A: No. The calculation runs entirely in your browser and nothing you enter is transmitted or saved on any server. #### Bitcoin Difficulty & Block Time Estimator URL: https://geratools.com/btc-difficulty-estimator Enter the current network hashrate and the hashrate at the last adjustment to predict the next Bitcoin difficulty change as a percentage, the implied average block time, and how long until the next 2016-block retarget. Based on the protocol's adjustment algorithm. How to use: 1. Enter current hashrate: Type today's network hashrate in EH/s from a live source. 2. Enter the last-adjustment hashrate: Add the network hashrate as it was when the current difficulty was set, roughly two weeks ago. 3. Read the projection: The tool shows the estimated difficulty change percent, the implied average block time, and the time remaining to the next retarget. FAQ: Q: How often does Bitcoin adjust difficulty? A: Every 2016 blocks, which at the target ten-minute pace is about every two weeks. At the end of each window the protocol compares how long those 2016 blocks actually took against the ideal of two weeks and scales difficulty to push the average back toward ten minutes. Q: How is the change percentage estimated? A: If hashrate is the main driver, the next difficulty scales by the ratio of current hashrate to the hashrate the present difficulty was set for. A 5 percent rise in hashrate implies roughly a 5 percent rise in difficulty. The protocol clamps each adjustment to a maximum of four times up or one quarter down. Q: Why might the real adjustment differ from this estimate? A: The actual algorithm uses the measured timestamps of the 2016 blocks, not hashrate directly. Variance in block discovery, timestamp manipulation within the allowed window, and hashrate changes mid-epoch all cause the real figure to drift from a hashrate-only estimate. Q: What does the implied block time tell me? A: While difficulty is still the old value but hashrate has changed, blocks arrive faster or slower than ten minutes. The implied block time is ten minutes scaled by the inverse hashrate ratio, so more hashrate means shorter intervals until the next retarget corrects them. Q: What are the clamp limits? A: A single retarget can at most quadruple difficulty (a +300 percent change) or cut it to a quarter (a -75 percent change). These bounds prevent extreme swings from a sudden hashrate shock or a timestamp anomaly. #### CBDC vs Crypto vs Stablecoin Comparison Tool URL: https://geratools.com/cbdc-comparison-tool Select two or three asset types to compare across twelve dimensions — counterparty risk, programmability, privacy, settlement finality, volatility, regulatory status, KYC, censorship risk, and cross-border use — using a structured reference matrix for finance professionals. How to use: 1. Choose two assets: Select the first and second asset types you want to put side by side, such as a CBDC and a fiat-backed stablecoin. 2. Optionally add a third: Turn on the third column to compare all three of CBDC, stablecoin, and decentralised crypto at once. 3. Read the matrix: Scan the twelve dimensions to see how each asset differs on risk, privacy, regulation, and usability. FAQ: Q: What is a CBDC? A: A central bank digital currency is a digital form of a country's sovereign money, issued and backed directly by the central bank. Unlike a stablecoin it is a direct claim on the central bank rather than a private issuer, giving it the lowest counterparty risk. Q: How does a stablecoin differ from a CBDC? A: A stablecoin is issued by a private company and aims to hold a peg to a fiat currency using reserves. It carries issuer and reserve risk, including the chance of de-pegging, whereas a CBDC carries no issuer credit risk because the state stands behind it. Q: Which is the most private? A: Decentralised crypto is typically pseudonymous, and privacy-focused chains add more. CBDCs are usually the least private because they are designed for anti-money-laundering traceability. Stablecoins sit in between but issuers can freeze addresses. Q: What does settlement finality mean here? A: Finality is how irreversible a payment is once made. CBDC payments are immediately and legally final as central-bank money. Crypto can be probabilistic on proof-of-work chains, while stablecoin on-chain transfers settle quickly but fiat off-ramps depend on the issuer. Q: Is this comparison authoritative? A: It is a generalised educational reference. Specific instruments vary, so a particular CBDC pilot, stablecoin, or blockchain may diverge from the typical values shown. Always verify against primary sources before making decisions. #### Crypto Arbitrage Profit Calculator URL: https://geratools.com/crypto-arbitrage-calculator Enter an asset's price on exchange A and B, your trade size, the taker fees on each venue, and estimated slippage to compute the gross spread, total fee drag, net profit in USD, and the minimum spread you need to break even on a spot arbitrage. How to use: 1. Enter prices on both venues: Put the buy price on the cheaper exchange (A) and the sell price on the more expensive one (B). The tool computes the gross spread between them. 2. Add trade size and fees: Enter your trade size in USD and the taker fee percentage charged by each exchange on entry and exit. 3. Read net profit and break-even: The tool shows gross profit, total fees, slippage cost, net profit, and the minimum percentage spread you need to come out ahead. FAQ: Q: How is arbitrage profit calculated? A: You buy on the cheaper exchange and sell on the dearer one. Gross profit is (sell price − buy price) ÷ buy price × trade size. From that you subtract the buy-side fee, the sell-side fee, and the slippage cost to get net profit. If the spread is smaller than total costs, the trade loses money. Q: Why does slippage matter so much? A: Arbitrage spreads are usually small, so even a fraction of a percent of slippage on each leg can erase the edge. Slippage grows with trade size relative to order-book depth, which is why large arbitrage trades are harder than they look on paper. Q: What is the break-even spread? A: It is the minimum percentage gap between the two prices at which net profit becomes zero — the sum of both fees plus total slippage as a percentage. Any real spread must exceed this to be worth executing. The tool computes it from your fee and slippage inputs. Q: Does this account for transfer time and withdrawal fees? A: No — it models a same-asset spot spread with taker fees and slippage. Cross-exchange arbitrage also incurs withdrawal fees and on-chain transfer time during which the spread can vanish. Add those costs separately before committing capital. Q: Is my trade data sent anywhere? A: No. All calculations run locally in your browser. Nothing you enter is transmitted or stored. #### Crypto DCA Target Price Calculator URL: https://geratools.com/crypto-dca-target-calculator Enter current holdings, average cost basis, target average price, market price, and periodic amount to compute how many additional dollar-cost-average purchases and how much total capital are needed to reach a new target average. Built for hodlers averaging down. How to use: 1. Enter your position: Type your current coin holdings and your present average cost per coin. 2. Set the target and price: Enter the average cost you want to reach and the market price you will be buying at. 3. Read the plan: The tool returns how many fixed-size purchases and how much total capital reach that target average. FAQ: Q: How does averaging down work mathematically? A: Your new average is total dollars spent divided by total coins held. Each purchase adds dollars to the numerator and coins to the denominator. Buying below your current average pulls the average down toward the buy price; the tool solves the algebra for the exact number of fixed-size buys that hit your target. Q: Why does it say my target is unreachable? A: You can only pull your average down to a level above your buy price, never below it. If you want a target average lower than the price you are buying at, no number of purchases at that price will get there. Lower the target or wait for a cheaper price. Q: Does the result assume a constant price? A: Yes. The math assumes every future purchase happens at the single market price you entered. Real prices drift between periods, so treat the buy count and capital as a snapshot and re-run the tool with fresh numbers before each purchase. Q: Why is the buy count rounded up? A: Purchases are whole transactions of a fixed dollar amount, so the tool rounds the exact fractional solution up to the next whole buy. That means the final average slightly overshoots your target on the favourable side rather than falling short. Q: Can I use this to raise my average instead? A: Yes. If your target is above your current average and your buy price is above the target, the tool computes how many buys lift the average up to it. This is useful when adding to a winning position while tracking the new blended cost. #### Crypto Position Size & Risk Calculator URL: https://geratools.com/crypto-position-size-risk Enter account balance, risk percentage per trade, entry price, and stop-loss to compute the maximum position size in USD and coin quantity. Shows fixed-fractional sizing alongside the Kelly Criterion and half-Kelly, with implied leverage. For disciplined crypto traders. How to use: 1. Enter account and risk: Type your account balance and the percentage of it you are willing to lose on this trade, commonly 1 percent. 2. Add entry and stop-loss: Enter your planned entry price and the stop-loss price where you will exit if wrong. 3. Read the position size: The tool returns the coin quantity and dollar value that keeps your loss to the chosen risk, plus optional Kelly sizing. FAQ: Q: How is position size derived from risk? A: Your dollar risk is the account balance times the risk percentage. The risk per coin is the distance between entry and stop-loss. Dividing dollar risk by risk per coin gives the coin quantity, so that if the stop is hit you lose exactly your intended percentage of the account. Q: What is the 1 percent rule? A: It is the convention of risking no more than 1 percent of your account on any single trade. Even a long losing streak then barely dents the balance, keeping you in the game. The tool defaults to 1 percent but lets you set any value. Q: What does implied leverage above 1x mean? A: If the position value exceeds your account balance, you would need leverage or margin to open it. A tight stop produces a large coin quantity for a small dollar risk, which can push position value past your balance. Treat high leverage as a warning to widen the stop or shrink the risk. Q: What is the Kelly Criterion? A: Kelly gives the bet fraction that maximises long-run compound growth, computed from your win rate and reward-to-risk ratio. The formula is win rate minus the loss rate divided by the reward ratio. It is mathematically optimal for growth but very aggressive, which is why many traders use half-Kelly. Q: Why does Kelly sometimes return zero? A: A non-positive Kelly fraction means your edge is negative given the win rate and payoff you entered. The mathematically optimal stake is then zero, which is the model's way of telling you the trade has no expected value and should be skipped. #### Crypto Tax Lot Calculator (FIFO / LIFO / HIFO) URL: https://geratools.com/crypto-tax-fifo-lifo Enter acquisition lots (date, quantity, cost basis) and disposal events (date, quantity, proceeds) to compute gains/losses under FIFO, LIFO, or HIFO accounting methods. Shows short-term vs long-term holding periods for self-filing crypto tax returns in the US or UK. How to use: 1. Add your acquisition lots: Enter each buy as a date, quantity, and total cost basis. These are the tax lots the tool will draw down from when you sell. 2. Add your disposal events: Enter each sell as a date, quantity, and total proceeds. The tool matches each disposal against your open lots. 3. Pick a method and read the gains: Choose FIFO, LIFO, or HIFO. The tool computes the matched cost basis, gain or loss, and short vs long-term holding period for each disposal. FAQ: Q: What is the difference between FIFO, LIFO, and HIFO? A: FIFO sells your oldest lots first, LIFO sells your newest first, and HIFO sells your highest-cost lots first. HIFO usually minimises taxable gains, but the IRS requires you to specifically identify lots to use it. FIFO is the default if no method is documented. Q: How is short-term versus long-term decided? A: In the US, a holding period of more than one year (more than 365 days) is long-term and taxed at a lower rate; one year or less is short-term. This tool flags each matched lot using the days between acquisition and disposal. Q: Does this handle partial lot disposals? A: Yes. If a disposal is smaller than the matched lot, only the proportional cost basis is consumed and the remainder of the lot stays open for the next disposal. The tool tracks remaining quantities across all events. Q: Is my data sent anywhere? A: No. All matching and gain calculation happens in your browser. Nothing you enter is uploaded, stored on a server, or shared. Close the tab and the data is gone. Q: Can I use this for a real tax return? A: It is a planning and estimation aid, not tax advice. The matching logic follows standard FIFO/LIFO/HIFO rules, but wash-sale treatment, fees, and jurisdiction-specific rules vary. Confirm figures with a qualified tax professional before filing. #### Liquidity Pool Position Value Calculator URL: https://geratools.com/liquidity-pool-position-calculator Input your initial token amounts, entry prices, current prices, and accumulated fees to compute the current value of a constant-product liquidity position, the impermanent loss versus holding, and the net profit or loss once fees are included. For DeFi liquidity providers. How to use: 1. Enter your deposit: Type the amount of each token you deposited and their USD prices at the time you entered the pool. 2. Enter current prices and fees: Type the current USD price of each token and the total fee income you have accumulated in USD. 3. Read your position P&L: The tool rebalances the pool using the constant-product rule, values your share at current prices, subtracts impermanent loss, and adds fees to show net profit or loss versus holding. FAQ: Q: How is the current value of an LP position computed? A: A constant-product pool keeps the product of the two token reserves constant. As prices move, the pool rebalances so the new token amounts satisfy that invariant. The tool recomputes your token balances at the current price ratio and values them at current prices. Q: What is the HODL value used for comparison? A: The HODL value is what your original deposited tokens would be worth today if you had simply held them instead of pooling. Subtracting your LP value from the HODL value gives the impermanent loss in dollars, the cost of providing liquidity. Q: How do fees factor into net P&L? A: Trading fees accrue to liquidity providers and partly or fully offset impermanent loss. Net P&L is your current LP value plus accumulated fees, minus what you originally deposited. If fees exceed impermanent loss, the position beats simply holding. Q: Does this handle Uniswap V3 concentrated liquidity? A: This calculator uses the Uniswap V2 constant-product model, which spreads liquidity across all prices. V3 concentrates liquidity in a range, amplifying both fees and impermanent loss when in range and converting fully to one asset when out of range, so V3 results will differ. Q: Why is my LP value lower than the HODL value? A: Because constant-product pools sell the appreciating asset and buy the depreciating one as prices diverge, leaving you with relatively more of the weaker asset. That rebalancing is exactly impermanent loss; trading fees are meant to compensate for it over time. #### NFT Royalty Calculator URL: https://geratools.com/nft-royalty-calculator Project NFT collection revenue from the mint plus ongoing creator royalties on secondary trades. Enter collection size, mint price, royalty percentage and monthly secondary volume to model income under full, partial and zero royalty enforcement. How to use: 1. Enter collection and mint details: Type the collection size and the mint price per NFT to compute primary sale revenue from a full mint. 2. Set the royalty percentage: Enter your on-chain royalty rate (commonly 5%–10%). This is applied to secondary trade volume to estimate ongoing income. 3. Add estimated secondary volume: Type expected monthly secondary trading volume. The tool projects monthly and annual royalty income under full, partial and zero enforcement. FAQ: Q: How is NFT royalty income calculated? A: Royalty income = secondary sale volume × royalty percentage. A 5% royalty on 100 ETH of monthly trading volume earns 5 ETH per month, on top of one-time primary mint revenue. Q: What is royalty enforcement? A: Royalties are not enforced by most blockchains at the protocol level — marketplaces choose whether to honour them. Full enforcement pays the stated rate, partial enforcement pays a blended fraction, and zero enforcement pays nothing on secondary sales. Q: What is a typical NFT royalty rate? A: Most collections set 5% to 10%. Above 10% can deter traders because it raises the effective cost of flipping. The optimal rate balances per-sale income against trading volume. Q: Does primary mint revenue include royalties? A: No. The mint is a primary sale, so the creator keeps the full mint price minus marketplace and gas fees. Royalties only apply to secondary resales after the mint. Q: Why model partial enforcement? A: Because real income often sits between full and zero. Volume splits across marketplaces with different policies, so a blended enforcement factor gives a more realistic projection than assuming everyone pays in full. #### Satoshi / Wei / Gwei Unit Converter URL: https://geratools.com/satoshi-wei-gwei-converter Enter any value in satoshi, mBTC, or BTC to convert across all Bitcoin denominations, or enter wei, gwei, or ether for Ethereum. Includes a USD equivalent with a manually-entered exchange rate. A must-have utility for developers writing smart contracts or payment integrations. How to use: 1. Pick a chain: Choose Bitcoin or Ethereum. Bitcoin shows satoshi, mBTC, and BTC; Ethereum shows wei, gwei, and ether. 2. Type into any unit field: Enter a value in whichever denomination you have. Every other unit updates instantly from the same underlying amount. 3. Add a price for USD value: Enter the current coin price in USD and the tool shows the dollar equivalent of the amount alongside the unit breakdown. FAQ: Q: How many satoshi are in one bitcoin? A: One bitcoin equals 100,000,000 satoshi, or 10 to the 8th power. The satoshi is the smallest indivisible unit of Bitcoin. One mBTC (millibitcoin) is one thousandth of a bitcoin, which is 100,000 satoshi. Q: How many wei are in one ether? A: One ether equals 1,000,000,000,000,000,000 wei, which is 10 to the 18th power. Gwei sits in between: one gwei is 10 to the 9th wei, and there are 10 to the 9th gwei in one ether. Gas prices are usually quoted in gwei. Q: Why does precision matter for wei conversions? A: Wei amounts can exceed what a standard JavaScript number represents exactly (about 9 quadrillion). This tool uses big-integer arithmetic for the wei base so large values convert without rounding errors, which is essential when computing exact token amounts. Q: Is gwei only used for gas? A: Gwei is most common for gas prices because typical fees fall in a readable range there, but it is a valid denomination for any amount. You can convert a gas price in gwei to its ether or wei cost and multiply by gas used to get a transaction fee. Q: Where does the USD value come from? A: You enter the exchange rate yourself, so the conversion stays accurate and works offline with no API dependency. Paste the current BTC or ETH price from any source and the tool multiplies it by the bitcoin or ether amount. ### Compliance & Policy #### ENERGY STAR Compliance Qualification Checker URL: https://geratools.com/energy-star-compliance-checker Select a product category — computers, monitors, appliances, HVAC, lighting, or commercial buildings — to display the applicable ENERGY STAR program requirements, efficiency thresholds, test method, certifying body, and typical compliance testing costs. How to use: 1. Select your product category: Pick the category that matches your product, from computers and monitors to HVAC, lighting, appliances, or commercial buildings. 2. Review the requirements: The tool shows the relevant ENERGY STAR specification, the headline efficiency threshold, the required test method, and the certifying body. 3. Plan your certification budget: Use the typical cost range to estimate testing and certification spend before you start the application. FAQ: Q: What is ENERGY STAR? A: ENERGY STAR is a voluntary US EPA program that certifies energy-efficient products and buildings. Products that meet the category specification can carry the label, which is widely recognised by US buyers and procurement programs. Q: How efficient does a product need to be? A: Each category has its own specification. Appliances typically must beat the federal minimum by a set margin, computers must stay under an annual energy cap, and commercial buildings must score 75 or higher in Portfolio Manager, meaning they outperform 75% of comparable buildings. Q: Who certifies an ENERGY STAR product? A: Most products are certified by an EPA-recognised third-party certification body, often after testing in an accredited lab. HVAC equipment additionally relies on AHRI ratings, while buildings are verified by a licensed Professional Engineer or Registered Architect. Q: How much does certification cost? A: It varies by category. Lighting and monitors can be a few thousand dollars per model, while HVAC certification with AHRI listing can run into the tens of thousands. Commercial building certification itself is free but third-party verification carries a fee. Q: Are these thresholds current? A: Specifications are revised periodically and version numbers change. Treat the figures here as a planning reference and confirm the exact current version and numeric limits on energystar.gov before submitting for certification. #### WEEE Compliance Checker URL: https://geratools.com/weee-compliance-checker Free WEEE compliance checker. Select your EEE product category and market (UK or EU) to identify Waste Electrical and Electronic Equipment Directive duties — producer registration, take-back, financing, marking and reporting — across the six current EEE categories and their collection targets. How to use: 1. Select your equipment category: Choose the WEEE category your product falls into, such as large equipment, IT and telecoms, or lamps. 2. Choose your market: Pick UK or EU so the tool applies the right registration scheme and collection-target framing. 3. Review your obligations: The tool lists registration, marking, take-back, financing and reporting duties plus the collection target context for your category. FAQ: Q: What are the WEEE categories? A: Since the 2018 open scope, WEEE uses six categories: 1) temperature exchange equipment, 2) screens and monitors, 3) lamps, 4) large equipment, 5) small equipment, and 6) small IT and telecommunications equipment. Older 10-category mappings are now consolidated into these six. Q: What are the main producer obligations? A: Producers must register with a national scheme or producer compliance scheme, mark equipment with the crossed-out wheelie bin symbol, finance the collection and treatment of WEEE, provide take-back, and report the quantities of EEE placed on the market and WEEE collected. Q: Who counts as a producer under WEEE? A: A producer is anyone who manufactures and sells EEE under their own brand, resells under their brand equipment made by others, or imports/exports EEE into a country on a professional basis, including most distance sellers shipping into a market. Q: What is the WEEE collection target? A: The EU WEEE Directive sets a collection target of 65% of the average weight of EEE placed on the market in the preceding three years, or alternatively 85% of WEEE generated. National schemes allocate producer obligations to help meet these targets. Q: Is my data sent anywhere? A: No. The checker uses a built-in mapping of categories to obligations and runs entirely in your browser. No product or business detail is transmitted or stored. ### City Costs & Commuting #### Miami Cost-of-Living Index URL: https://geratools.com/miami-cost-of-living-index Benchmarks Miami's composite cost-of-living index (123 vs US=100) across housing, groceries, transportation, utilities, and healthcare so you can see how far your salary really goes in Miami. How to use: 1. Enter your current city index: Type the cost-of-living index of your current city (US national average is 100). Leave it at 100 to compare directly against the national baseline. 2. Enter your current income or budget: Add your current monthly take-home pay or spending so the tool can convert it to the equivalent amount needed in Miami. 3. Read the breakdown: The result shows Miami's category indices and the equivalent budget you would need to maintain the same standard of living. FAQ: Q: What does a cost-of-living index of 123 mean? A: An index of 123 means Miami is roughly 23% more expensive than the US national average, which is set to 100. Housing is the single biggest driver of that premium. Q: Which categories does the index cover? A: This composite blends housing, groceries, transportation, utilities, healthcare, and other goods and services. Each category carries a weight reflecting how much of a typical household budget it consumes. Q: How do I convert my salary to Miami terms? A: Divide your income by your current city index, then multiply by Miami's index of 123. The tool does this automatically: equivalent = income x (123 / your index). Q: Is housing really the main reason Miami is expensive? A: Yes. Housing carries the heaviest budget weight and sits well above the national average in Miami, so it dominates the composite figure far more than groceries or utilities. Q: Are these numbers exact? A: They are survey-based estimates meant for planning and comparison, not precise quotes. Actual costs vary by neighborhood, lifestyle, and household size. #### Oklahoma City Cost-of-Living Index URL: https://geratools.com/oklahoma-city-cost-of-living-index Benchmark Oklahoma City's cost of living against the US average using a composite index of 87, with category sub-indices for housing, groceries, transportation, utilities, and healthcare — and see what a given monthly budget really buys in OKC. How to use: 1. Enter your reference budget: Type the monthly budget you would spend at the US-average cost level, or what you spend now in an average-cost city. 2. Review the OKC index: See Oklahoma City's composite index of 87 and the category sub-indices for housing, groceries, transportation, utilities, and healthcare. 3. Read your OKC-equivalent cost: The tool scales each spending category by its OKC index to show your equivalent monthly cost and how much you save versus the national average. FAQ: Q: What is Oklahoma City's cost-of-living index? A: Oklahoma City has a composite cost-of-living index of about 87, where the US national average equals 100. That means a typical basket of expenses costs roughly 13% less in OKC than in an average American city. Q: Which category makes Oklahoma City cheap? A: Housing is the biggest driver. OKC's housing sub-index sits near 75 versus the national 100, a 25% discount. Groceries, utilities, and healthcare are much closer to the national average, so housing does most of the affordability work. Q: How does the calculator convert my budget? A: It splits a US-average budget into category weights — housing, groceries, transportation, utilities, healthcare, and other — then scales each slice by Oklahoma City's index for that category. Summing the scaled slices gives your OKC-equivalent monthly cost. Q: Is an index of 87 good for a major city? A: Yes. Among large US metros, an index of 87 is notably affordable. Many coastal cities exceed 130 or 150, so a salary that feels tight elsewhere stretches considerably further in Oklahoma City. Q: Does this include taxes? A: The composite index reflects typical consumer expenses rather than income taxes. Oklahoma's moderate state income tax and 8.625% OKC sales tax are separate factors you would layer on for a full picture. #### Seattle Commute Cost Calculator URL: https://geratools.com/seattle-commute-cost-calculator Free Seattle commute cost calculator comparing an ORCA transit pass against driving. Adds gas at your local price, IRS-equivalent per-mile vehicle cost, and downtown parking (~$225/mo) to show which option saves you money each month. Runs in your browser. How to use: 1. Enter your driving distance: Type your round-trip commute distance in miles and how many days per month you commute. 2. Enter your vehicle costs: Set your car's MPG, the local gas price, and monthly parking. The tool adds a per-mile wear cost so the comparison reflects true driving cost. 3. Compare with transit: Enter the ORCA monthly pass price (default $99) and see which option is cheaper, plus the monthly difference. FAQ: Q: How is driving cost calculated? A: Driving cost = monthly miles divided by MPG times gas price, plus a per-mile vehicle wear cost (default $0.21/mi for maintenance and depreciation), plus your monthly parking. This captures more than just fuel, which is why driving often costs more than people expect. Q: What is the ORCA pass? A: ORCA is the regional transit card for Seattle-area buses, light rail, ferries, and trains. A monthly pass commonly runs around $99 depending on your fare level. The tool uses $99 by default — adjust it to your actual pass. Q: Why include a per-mile wear cost? A: Fuel alone understates driving. Tires, oil, brakes, and depreciation accrue with every mile. The IRS standard mileage rate bundles all of this; the maintenance-and-depreciation slice is roughly $0.20–$0.25/mi, which this tool adds on top of fuel. Q: Does this include car payments or insurance? A: No, by default. Those are largely fixed whether or not you commute, so the tool focuses on the marginal cost of commuting (fuel, wear, parking). You can fold a payment into the parking field if you want to include it. Q: Is my data sent anywhere? A: No. The whole calculation runs in your browser. Your commute details never leave your device. #### St. Louis Parking Cost Estimator URL: https://geratools.com/st-louis-parking-cost-estimator Estimates parking costs in St. Louis using local median rates — about $85/month for a garage permit and roughly $1.50/hour for metered street parking — plus event-rate multipliers and your weekly schedule. Runs entirely in your browser. How to use: 1. Choose your parking type: Pick a monthly garage permit or pay-as-you-go street and lot parking, which the tool prices using St. Louis median rates. 2. Enter your usage: For street parking, enter hours parked per day and days per month. For a monthly permit, the flat rate applies regardless of how often you park. 3. Read daily, monthly, and annual totals: The calculator converts your inputs into a per-day, per-month, and per-year cost so you can budget and compare options. FAQ: Q: How much does parking cost in St. Louis? A: A monthly garage permit in St. Louis runs about $85, while metered street parking is roughly $1.50 per hour. Lot and event parking near downtown venues and the stadiums can be considerably higher. Q: Is a monthly permit cheaper than paying per hour? A: Often yes for regular commuters. If you park more than roughly 57 hours a month at $1.50/hour, an $85 monthly permit usually costs less. The tool shows both totals so you can compare directly. Q: What is the event-rate multiplier? A: Near downtown venues, Busch Stadium, and the Enterprise Center, lots and garages raise prices during games, concerts, and festivals. The multiplier scales your normal rate up for event days to estimate the premium. Q: Do these rates include taxes? A: St. Louis applies sales tax to paid parking, which may be added to the posted rate. This estimator uses base rates, so your actual charge could be slightly higher at the pay station. Q: Are rates the same across all neighborhoods? A: No. Downtown, the Central West End, and the Delmar Loop tend to be priciest, while outer neighborhoods and surface lots are cheaper. The defaults reflect a city median, so adjust them for your specific area. ### Social Media & Creator #### TikTok Hashtag Limit Helper URL: https://geratools.com/tiktok-hashtag-limit-helper Paste or type your hashtags and this tool counts them, measures their character cost against the caption limit, flags malformed tags, and recommends a clean set so your TikTok post is never suppressed for over-tagging. Runs in your browser. How to use: 1. Paste your hashtags: Type or paste your hashtags into the box, separated by spaces, commas, or new lines. The tool detects each tag automatically. 2. Read the count and character cost: See how many valid hashtags you have and how many characters they consume against TikTok's 2,200-character caption limit. 3. Fix flagged tags and trim to the sweet spot: Remove malformed or duplicate tags the tool flags and trim toward the recommended 3 to 5 focused hashtags for the strongest reach. FAQ: Q: Is there a hard hashtag limit on TikTok? A: TikTok does not enforce a fixed count of hashtags, but every hashtag shares your caption's 2,200-character budget. In practice that caps you well before you run out of tags, and over-tagging looks spammy and can hurt reach, so a tight set works best. Q: How many hashtags should I use on TikTok? A: Three to five focused hashtags is the widely recommended sweet spot. Mix one or two broad tags for reach with two or three specific niche tags for relevance. Stuffing twenty generic tags rarely helps and can signal low-quality content to the algorithm. Q: What makes a hashtag invalid on TikTok? A: Hashtags should contain only letters, numbers, and underscores after the hash symbol. Spaces, punctuation, or symbols break the tag, so multi-word tags must be joined without spaces. This tool flags any tag containing characters TikTok will not link. Q: Do hashtags count toward my caption character limit? A: Yes. Every character of every hashtag, including the hash symbol, counts toward the 2,200-character caption cap. This tool sums that cost so you know how much caption space your tags leave for your actual message. Q: Should I repeat the same hashtags on every post? A: Avoid copy-pasting an identical block of tags on every video, which can look automated. Rotate a small core set with a few post-specific tags. This helper flags duplicates within a single post so you do not waste budget on repeats. ### Astronomy #### Lunar Phase & Moonlight Exposure Calculator URL: https://geratools.com/lunar-phase-exposure Estimate the exposure value of moonlight from lunar phase percentage and moon altitude, then derive shutter speed, aperture, and ISO for moonlit landscapes and astrophotography. Includes a Looney 11 style brightness model. Runs entirely in your browser. How to use: 1. Set the moon phase and altitude: Enter the illuminated fraction of the moon (0 to 100 percent) and roughly how high it is above the horizon in degrees. 2. Fix two of three exposure values: Enter the ISO and aperture you plan to shoot, and the calculator solves for the matching shutter speed for the scene EV. 3. Read and bracket: Use the suggested shutter as a starting point, then bracket a stop either side. Moonlit scenes vary with haze, snow, and surface reflectivity. FAQ: Q: How bright is moonlight compared to sunlight? A: A full moon is roughly 400,000 times dimmer than direct sun, about 18 to 19 stops less light. That is why a sunny day exposes near EV 15 while a full-moon landscape sits around EV minus 3 to minus 4 at the ground. Q: What is the Looney 11 rule? A: It is the night-time cousin of the Sunny 16 rule. For a detailed, well-exposed full moon disc, set aperture to f/11 and shutter to 1 over the ISO. This tool generalises that idea to whole moonlit landscapes, not just the lunar disc. Q: Why does moon altitude matter? A: Light from a low moon passes through far more atmosphere, dimming and reddening it. A moon near the horizon delivers roughly a stop less usable light than one overhead, so the calculator reduces the scene EV as altitude drops. Q: How does phase change the exposure? A: Brightness scales with the illuminated fraction, but not linearly. A half moon gives far less than half a full moon's light because of shadowing on its surface. The model drops about one stop per major phase step, so plan on a few extra stops away from full. Q: Can I photograph the moon's surface with these settings? A: No. The bright lunar disc needs Looney 11 settings (f/11, 1 over ISO) or it blows out. These landscape settings are for the dim ground lit by the moon, which is many stops darker than the disc itself. #### Moon Phase & Illumination Calculator URL: https://geratools.com/moon-phase-illumination Uses Julian date math to compute lunar age in days, the named phase, and percent illumination for any calendar date. For astrophotographers avoiding moonlit nights and outdoor enthusiasts planning by the moon. How to use: 1. Pick a date: Choose the calendar date you want to check. The tool defaults to today so you can plan tonight's session immediately. 2. Read the phase and age: The result shows the lunar age in days since the last new moon and the named phase, from new through full and back. 3. Use the illumination percent: Percent illumination tells you how much of the disc is lit. Low values near new moon are best for deep-sky imaging. FAQ: Q: How is the moon phase calculated without a live ephemeris? A: The tool converts your date to a Julian Day Number and measures how far it is past a known reference new moon. Dividing that by the synodic month length of about 29.53 days gives the lunar age, which maps directly to the phase. Q: How accurate is the illumination percentage? A: It is a close approximation using a cosine model of the phase angle. It is typically within a percent or two of a full ephemeris, which is more than enough for planning whether the sky will be dark or washed out. Q: Why does astrophotography care about moon phase? A: A bright moon floods the sky with scattered light, drowning faint nebulae and galaxies. Deep-sky imagers schedule their sessions around new moon, when illumination is near zero and the sky is darkest. Q: What is the synodic month? A: The synodic month is the time from one new moon to the next, averaging 29.53 days. It is longer than the orbital period because the Earth also moves around the Sun, so the Moon must travel a little extra to line up again. Q: Does this account for my time zone? A: The calculation uses noon on the selected calendar date as a reference point, so the phase shown is correct for that day worldwide. Phase changes slowly, about 12 degrees per day, so a few hours of time-zone offset rarely changes the named phase. #### Astrophoto Golden Hour & Astronomical Twilight Calculator URL: https://geratools.com/photography-golden-hour-calculator Enter latitude, longitude, and date to compute sunrise, sunset, civil, nautical, and astronomical twilight using the NOAA solar position algorithm. Plan golden hour and dark-sky imaging windows. How to use: 1. Enter your location: Type your latitude and longitude in decimal degrees, using negative values for south and west. 2. Pick the date: Choose the date you plan to shoot so the sun's declination and equation of time are computed for that day. 3. Read the windows: The tool lists sunrise, sunset, golden hour, and the start and end of civil, nautical, and astronomical twilight in your local time. FAQ: Q: What is astronomical twilight and why does it matter? A: Astronomical twilight is when the sun is between 12 and 18 degrees below the horizon. Once it ends the sky is fully dark with no residual sunlight, which is the window deep-sky astrophotographers need for faint targets. Q: How accurate are the times? A: The NOAA solar position algorithm used here is accurate to within about a minute for dates between 1900 and 2100. It ignores atmospheric refraction variations and elevation above sea level, which can shift real horizon times by a minute or two. Q: What counts as golden hour? A: Golden hour is the period when the sun is between roughly 6 degrees below and 6 degrees above the horizon, giving warm, low-angle light. This tool marks it from the start of civil twilight through sunrise, and again from sunset to the end of civil twilight. Q: Why do I need longitude if I only care about my time zone? A: Solar events depend on your exact longitude, not just the time zone. The tool computes the event in solar time then shifts it to your local clock using the offset you supply, so two cities in the same zone get different sunrise times. Q: What is the difference between civil, nautical, and astronomical twilight? A: They mark how far the sun is below the horizon: civil at 6 degrees, nautical at 12, astronomical at 18. Each darker stage suits different work, from landscape blue hour to navigation to faint-object astrophotography. #### Sunrise/Sunset Azimuth Angle Calculator URL: https://geratools.com/sunrise-sunset-angle Compute sunrise and sunset azimuth (compass bearing) from latitude, longitude, and date using the sun's declination and the standard solar azimuth formula. Plan landscape and architectural shots by knowing exactly where the sun appears on the horizon. Runs in your browser. How to use: 1. Enter your location: Type the latitude and longitude of your shooting spot in decimal degrees (north and east positive, south and west negative). 2. Pick the date: Choose the date you plan to shoot. The sun's declination changes through the year, so the rise and set bearings shift with the season. 3. Read the bearings: The calculator returns the sunrise and sunset azimuth as a compass bearing from true north, plus a plain-English direction like ENE so you can align your composition. FAQ: Q: What is solar azimuth? A: Azimuth is the compass bearing to the sun measured clockwise from true north: 0 degrees is due north, 90 east, 180 south, 270 west. Sunrise and sunset azimuth tell you the exact direction the sun crosses the horizon on a given day. Q: Why does the sun not always rise due east? A: The sun only rises due east and sets due west at the spring and autumn equinoxes. Through the year its rise and set points swing north (toward summer) and south (toward winter) as the sun's declination changes between about plus and minus 23.4 degrees. Q: Does latitude change the rise and set direction? A: Yes. The same declination produces a larger azimuth swing at higher latitudes. Near the equator the sun rises close to east year-round; at far-northern latitudes the summer sunrise can be well north of east. Q: How accurate is this calculator? A: It uses a standard declination model and the level-horizon azimuth formula, accurate to roughly a degree for planning. It assumes a flat sea-level horizon and ignores atmospheric refraction and terrain, which can shift the visible rise point slightly. Q: Is the bearing relative to true north or magnetic north? A: True (geographic) north. If you sight with a magnetic compass, apply your local magnetic declination to convert. Most phone compass apps can display true north directly. #### Telescope Focal Ratio (f/ratio) Calculator URL: https://geratools.com/telescope-focal-ratio-calculator Input telescope aperture and focal length to calculate the focal ratio, depth of focus, and diffraction-limited resolution (Dawes and Rayleigh limits). For telescope buyers and astrophotographers comparing optics. How to use: 1. Enter aperture: Type your telescope's aperture (objective diameter) in millimeters, which is the headline spec like 200 mm for an 8-inch scope. 2. Enter focal length: Type the focal length in millimeters, usually printed near the focuser or in the manual, for example 1000 mm. 3. Read the optics: The tool returns the focal ratio, a fast or slow speed label, the critical depth of focus, and the diffraction-limited resolution in arcseconds. FAQ: Q: What is focal ratio and why does it matter? A: Focal ratio is focal length divided by aperture, written as f/8 for example. It sets how bright the image is per unit area: low f-numbers (f/4 to f/5) are fast and great for wide-field astrophotography, while high f-numbers (f/10 and up) are slow but give high magnification for planets and the moon. Q: How is the Dawes limit calculated? A: The Dawes limit is the empirical resolving power for a telescope splitting close double stars: 116 divided by aperture in millimeters gives arcseconds. The Rayleigh criterion is slightly more conservative at 138 over aperture. Both improve with larger aperture, not focal length. Q: What is depth of focus and why does fast optics matter? A: Depth of focus is the tiny range of focuser travel that stays in sharp focus. It shrinks with the square of focal ratio (about 2.2 microns times f-ratio squared at green wavelengths). A fast f/4 scope has a razor-thin focus zone, which is why critical focus is harder than at f/10. Q: Does a longer focal length mean better resolution? A: No. Resolution is set by aperture alone through diffraction. Longer focal length only increases image scale and magnification, spreading the same detail over more pixels or a wider eyepiece field. Aperture is what determines the finest detail a telescope can show. Q: How do I change my telescope's focal ratio? A: Add a focal reducer to lower the f-number and widen the field, or a Barlow or Powermate to raise it for higher magnification. Both change effective focal length while aperture stays fixed, so the focal ratio shifts in proportion. #### Sunrise & Sunset Calculator URL: https://geratools.com/sunrise-sunset-calculator Free sunrise and sunset calculator. Enter any latitude, longitude and date to get precise sunrise, solar noon, and sunset times in UTC — plus daylight duration, solar declination and equation of time. Uses a local astronomical formula; no network required. How to use: 1. Enter a date: Pick the date you want to look up using the date picker. It defaults to today. 2. Enter your coordinates: Type your latitude (positive = North, negative = South) and longitude (positive = East, negative = West). The default is London. 3. Read the UTC times: Sunrise, solar noon, and sunset are shown in UTC. Add your UTC offset to convert to local clock time — for example, UTC+1 means add one hour. 4. Check the horizon diagram: The arc diagram visualises the sun path above the horizon, with the sunrise and sunset markers and the peak at solar noon. FAQ: Q: What formula does this calculator use? A: It implements the NOAA Solar Calculator algorithm, which is itself a practical version of Jean Meeus's "Astronomical Algorithms". The Julian Day Number is computed with the Fliegel–Van Flandern integer formula, then the sun's ecliptic longitude, right ascension, and declination are derived from the Julian centuries since J2000.0, and finally the hour angle is solved from the standard spherical-trigonometry relation — cos(H) = (cos(zenith) - sin(lat)*sin(dec)) / (cos(lat)*cos(dec)) — to place sunrise and sunset on either side of solar noon. Q: Why are times given in UTC and not my local time? A: UTC is the universal reference that is unambiguous regardless of time zone or daylight-saving rules. To convert to your local time, simply add your UTC offset. For example, if you are in Paris (UTC+2 in summer), add 2 hours to every time shown. Q: How accurate are the results? A: For latitudes between roughly -65 deg and +65 deg the algorithm is accurate to within about one minute of the true time. Closer to the poles the sun skims the horizon at a shallow angle, stretching any small angular error into a larger time error. For extreme polar latitudes, expect an accuracy of a few minutes. Q: What does solar noon mean, and why does it differ from 12:00? A: Solar noon is the moment the sun reaches its highest point in the sky — its meridian transit. It equals 12:00 local solar time by definition, but it rarely coincides with noon on your clock for two reasons: your location is probably not exactly on your time-zone's central meridian, and the equation of time shifts solar time by up to about 16 minutes depending on the time of year due to the eccentricity of Earth's orbit and the obliquity of the ecliptic. Q: What is the equation of time, and why does it matter? A: The equation of time is the difference between apparent solar time (as read by a sundial) and mean solar time (as kept by a clock). It ranges from about -14 minutes in February to +16 minutes in November. The calculator reports it so you can understand why solar noon is not always at your midday, and it is baked into the solar-noon calculation automatically. Q: What happens at extreme latitudes like the Arctic or Antarctic? A: Near the poles, the sun can stay continuously above the horizon for weeks (midnight sun / polar day) or continuously below it (polar night). When that occurs the hour-angle formula has no solution — cos(H) falls outside the range -1 to 1 — and the calculator reports a polar-condition message instead of times. Roughly speaking, polar day occurs in summer for latitudes above about 66.5 deg (or below -66.5 deg in the southern hemisphere). Q: Is any data sent to a server? A: No. Every calculation runs entirely inside your browser using JavaScript. No coordinates, dates, or results are ever transmitted to any server. #### Golden Hour Calculator URL: https://geratools.com/golden-hour-calculator Free golden hour calculator. Enter your coordinates and date to get morning and evening golden-hour windows, blue-hour windows, sunrise, solar noon and sunset — accurate to the minute, 100% in-browser. How to use: 1. Enter your date: Pick the date you are planning to shoot or simply want to check. 2. Set your coordinates: Enter latitude (positive = North, negative = South) and longitude (positive = East, negative = West). Use Google Maps or your phone's location to find your exact coordinates. 3. Set your UTC offset: Enter your local UTC offset, e.g. +1 for CET, -5 for US Eastern, +5.5 for India. Half-hour offsets are supported. 4. Read the results: The colour-coded timeline and results table show morning blue hour, morning golden hour, sunrise, solar noon, sunset, evening golden hour and evening blue hour with durations. FAQ: Q: What is the golden hour in photography? A: Golden hour refers to the roughly one-hour period just after sunrise and just before sunset when the sun is low in the sky. At this angle sunlight travels through a greater thickness of atmosphere, scattering blue wavelengths and leaving warm orange and amber tones. Shadows are long and soft, contrast is gentle, and skin tones look flattering — which is why portrait and landscape photographers prize it above all other light. Q: How is the golden hour defined technically? A: This calculator defines it as the window when the sun's altitude is between -4° and +6° above the horizon. Below -4° the sky is still dark (astronomical twilight) and the warm glow is absent; above +6° the sun is high enough that the warming effect fades and light becomes harsher. The morning window runs from roughly -4° (rising) to +6°; the evening window from +6° (setting) back to -4°. Q: What is the blue hour? A: Blue hour falls just before morning golden hour and just after evening golden hour, when the sun is between -6° and -4° altitude. The sun is below the horizon, so direct sunlight is absent, but scattered light in the upper atmosphere creates a pure cool-blue sky. It is ideal for urban photography, cityscapes, and any shot where you want ambient sky light without a strong light source. Q: How accurate are the times? A: The algorithm is based on the NOAA Solar Calculator (Jean Meeus "Astronomical Algorithms"). For latitudes between -65° and +65° it is accurate to within about one minute. At extreme latitudes near the poles accuracy decreases, and the calculator will flag polar-day or polar-night conditions automatically. Q: Does the golden hour last exactly one hour? A: No. Duration varies significantly with latitude, season, and the angle at which the sun rises or sets. Near the equator the sun rises and sets steeply, so golden hour can be as short as 20-30 minutes. At high latitudes in summer the sun moves nearly parallel to the horizon and golden hour can last two hours or more. Use the duration column in the results table to see the exact length for your location and date. Q: Why do I need to enter a UTC offset? A: The solar formula works in Universal Time (UTC). Entering your local UTC offset converts all results to your local clock time so you can set your alarm correctly. If you prefer raw UTC simply leave the offset at 0. #### Blue Hour Calculator URL: https://geratools.com/blue-hour-calculator Free blue hour calculator: see the precise start and end of the blue hour, golden hour, civil twilight, nautical twilight and astronomical twilight for any GPS coordinate and date. All calculations run in your browser — no data is uploaded. How to use: 1. Enter your date: Choose the date you want to shoot or plan for using the date picker. 2. Set your coordinates: Type your latitude and longitude, or click "Use my location" to fill them automatically from your browser's GPS. 3. Pick your UTC offset: Select your timezone offset so all times appear in local clock time rather than UTC. 4. Read the timeline: The colour-coded bar shows every phase of light across the 24-hour day — blue for blue hour, amber for golden hour, and dark bands for nautical and astronomical twilight. 5. Copy your shoot plan: Hit "Copy all times" to paste a plain-text summary into your notes app, calendar or message thread. FAQ: Q: What is the blue hour? A: The blue hour is the period of twilight just before sunrise and just after sunset when the sun sits between 6 degrees and 0 degrees below the horizon (civil twilight). Sunlight scatters heavily in the atmosphere, bathing the sky in a cool, deep blue that photographers, cinematographers and architects prize for its soft, even, directionless quality. It typically lasts 20 to 40 minutes depending on your latitude and the time of year. Q: How is the blue hour calculated? A: The calculator uses the NOAA solar-position algorithm (based on Jean Meeus "Astronomical Algorithms"). It computes the solar declination and the equation of time from the Julian Day Number, then solves the hour-angle equation cos(HA) = (cos(z) - sin(lat)*sin(dec)) / (cos(lat)*cos(dec)) for each zenith angle z. The blue hour corresponds to solar elevations from 0 degrees (standard horizon, zenith 90.833 degrees with atmospheric refraction) to -6 degrees (civil twilight, zenith 96 degrees). The golden hour corresponds to elevations from -4 degrees to +6 degrees. Q: What is the difference between civil, nautical and astronomical twilight? A: Civil twilight runs from sunset (0 degrees elevation) to -6 degrees below the horizon — the sky is still bright enough for outdoor activity without artificial light. Nautical twilight spans -6 degrees to -12 degrees — the horizon is just visible at sea, stars are bright, but the sky has a distinct blue-grey cast. Astronomical twilight covers -12 degrees to -18 degrees — only then is the sky truly dark enough for faint-object astronomy. Q: When is the best time for blue hour photography? A: Evening blue hour (just after sunset) is generally preferable for planning because you can arrive before sunset, shoot golden hour, then stay for the blue hour. The sky cools from warm oranges to deep indigo in roughly 20-40 minutes. Morning blue hour ends at sunrise, so you must be in position before dawn. Use the calculator to get the exact window for your chosen day and location. Q: How long does the blue hour actually last? A: Typically 20 to 40 minutes at mid-latitudes, but it varies considerably. Near the equator the sun drops steeply below the horizon, so twilight can be as short as 15 minutes. At high latitudes (above 60 degrees North or South) the sun travels at a shallow angle and the blue hour can extend to an hour or more — and around the summer solstice it may blend directly into the opposite twilight without a true night. Q: Does this calculator work for polar regions? A: Yes. If the sun never rises (polar night) or never sets (midnight sun) on your chosen date, the calculator detects this and shows the appropriate message instead of producing times. The detection uses the same solar declination and latitude comparison that drives the mathematical singularity in the hour-angle formula. Q: Is GPS permission required? A: No. Typing latitude and longitude manually works without any location permission. The "Use my location" button requests browser geolocation to fill the coordinates for you — you can dismiss the permission prompt and type in coordinates instead. All computation runs locally; no coordinates are sent to a server. #### Angular Resolution Calculator URL: https://geratools.com/angular-resolution-calculator Free angular resolution calculator. Compute the Rayleigh diffraction limit, Dawes limit for visual telescopes, Abbe microscope resolution, pixel scale (arcsec/px), linear size on a target, and the required aperture for a given resolution — 100% client-side. How to use: 1. Choose the calculation mode: Pick from Rayleigh criterion, Dawes limit, Abbe microscope limit, pixel scale, linear resolution on a target, or required aperture — each mode shows only the inputs you need. 2. Enter your optical parameters: For telescopes enter the aperture diameter in mm and the observation wavelength in nm (green light is ~550 nm). For microscopes enter the numerical aperture (NA) and wavelength. 3. Read the diffraction-limited resolution: The primary result is shown in arcseconds. Equivalent values in arcminutes, degrees, and microradians are listed below it so you can cross-check against your specification sheet. 4. Use Pixel Scale mode for astrophotography: Enter your focal length in mm and your camera sensor pixel pitch in micrometres. The tool returns arcseconds per pixel and flags whether you are over- or under-sampled relative to the Nyquist limit. 5. Find the aperture you need: Switch to Required Aperture mode and enter a target resolution in arcseconds plus a wavelength. The calculator inverts the Rayleigh formula to give you the minimum aperture in mm. FAQ: Q: What is angular resolution and why does it matter? A: Angular resolution is the smallest angle between two point sources that an optical system can distinguish as separate. It determines how much fine detail a telescope, camera, or microscope can reveal. A smaller angle means finer detail. Q: What is the Rayleigh criterion formula? A: The Rayleigh criterion states that two point sources are just resolved when the central maximum of one falls on the first minimum of the other. The formula is: theta = 1.22 * lambda / D, where lambda is the wavelength of light and D is the aperture diameter (both in the same units). The result is in radians. Q: How does the Dawes limit differ from the Rayleigh criterion? A: The Dawes limit is an empirical rule for visual observation of double stars through a telescope: theta (arcsec) = 116 / D_mm. It was derived from practical observation rather than wave optics and applies specifically to the human eye resolving double stars at the eyepiece. For astrophotography or non-visual work the Rayleigh criterion is more appropriate. Q: What is the Abbe diffraction limit for microscopes? A: Ernst Abbe showed that the minimum resolvable feature size under a microscope is d = lambda / (2 * NA), where NA is the numerical aperture of the objective lens. With a 100x oil-immersion objective (NA 1.4) and green light (550 nm), this gives roughly 196 nm — better than a dry objective because immersion oil raises the effective NA. Q: What does pixel scale (arcsec/px) mean? A: Pixel scale tells you how many arcseconds of sky each camera pixel covers. The formula is s = (pixel_size_um / focal_length_mm) * 206.265. A scale of 1 arcsec/px means each pixel samples 1 arcsecond of sky. For good sampling under typical seeing (2–3 arcsec FWHM) aim for roughly 1–1.5 arcsec/px; undersampling wastes potential resolution and oversampling reduces signal-to-noise per pixel. Q: Does atmospheric seeing affect the diffraction limit? A: Yes. The theoretical diffraction limit only applies in space or at exceptional high-altitude observatory sites. At sea level, atmospheric turbulence (seeing) typically limits resolution to 1–3 arcseconds regardless of aperture. Large telescopes use adaptive optics to partially correct this. The calculator gives the diffraction-limited figure — actual performance will be worse unless seeing is corrected. #### Light-Year Distance Calculator URL: https://geratools.com/light-year-distance-calculator Convert any cosmic distance between light-years, parsecs, AU, km, light-seconds and more. Instantly see how long light takes to cross that distance. Covers 15 named cosmic landmarks from the Moon to the edge of the observable Universe. 100% client-side — no data sent to any server. How to use: 1. Enter a distance: Type any positive number into the Distance field and select its unit (light-years, km, AU, parsecs, etc.). 2. Pick a cosmic landmark (optional): Choose from 15 pre-loaded destinations — from the Moon to the edge of the observable Universe — to auto-populate the distance. 3. Read the light travel time: The blue banner shows exactly how long light takes to cross that distance, in the most human-readable unit from milliseconds up to billion years. 4. Read the full unit table: Scroll down to see the distance expressed in every supported unit simultaneously. 5. Expand the reference table: Click "Cosmic distances reference table" to see all 15 landmarks with their distances and light travel times side-by-side. FAQ: Q: What exactly is a light-year? A: A light-year is the distance light travels through a vacuum in exactly one Julian year (365.25 days). Using the SI definition of the speed of light (299,792,458 m/s exactly), one light-year equals 9,460,730,472,580,800 metres, or about 9.461 trillion kilometres (9.461 × 10^12 km). It is a unit of distance, not time. Q: How is light travel time calculated? A: The formula is simply t = d ÷ c, where d is the distance in metres and c is the speed of light (299,792,458 m/s). For example, the Sun is 1 AU = 149,597,870,700 m away; dividing by c gives 499.0 seconds, or about 8 minutes and 19 seconds — so sunlight we see right now left the Sun over 8 minutes ago. Q: What is the difference between a light-year and a parsec? A: A parsec is defined by parallax geometry: it is the distance at which 1 AU subtends an angle of 1 arcsecond. The exact value is 1 pc = AU × (648,000 ÷ π) ≈ 3.0857 × 10^16 m, which equals roughly 3.2616 light-years. Parsecs are preferred by professional astronomers because they arise directly from trigonometric parallax measurements, while light-years are more intuitive for public science communication. Q: How far away is Proxima Centauri in light-years? A: Proxima Centauri, the closest known star to the Sun, is approximately 4.2441 light-years away. Light from Proxima takes about 4.24 years to reach Earth. If a spacecraft could travel at 0.1c (one-tenth the speed of light), the journey would take around 42 years; even the fastest probes ever launched would take tens of thousands of years. Q: How big is the observable Universe in light-years? A: The comoving radius of the observable Universe is approximately 46.5 billion light-years (4.65 × 10^10 ly). This is larger than 13.8 billion light-years — the age of the Universe in years — because cosmic expansion has carried the most distant objects further away since their light was emitted. The light from the farthest galaxies we can detect was emitted only a few hundred million years after the Big Bang. Q: Can I convert light-years to kilometres with this tool? A: Yes. Enter a value in light-years and the table immediately shows the equivalent in kilometres (and nine other units). One light-year equals exactly 9,460,730,472,580.8 km — just over 9.46 trillion kilometres, or roughly 63,241 AU. #### Redshift Calculator URL: https://geratools.com/redshift-calculator Free redshift calculator — enter redshift z, recession velocity or observed wavelength to get comoving distance, luminosity distance, lookback time, distance modulus, scale factor, CMB temperature and a spectral-line stretch table. Flat ΛCDM model, Planck 2018 parameters, 100% client-side. How to use: 1. Choose your input type: Select whether you know the redshift z directly, the recession velocity in km/s, or the rest and observed wavelengths in nanometres. 2. Enter your value: Type the redshift (e.g. 1.0 for a high-z galaxy), velocity in km/s, or the two wavelengths. All results update instantly. 3. Read the cosmological distances: The calculator shows comoving distance, luminosity distance, angular diameter distance, lookback time, scale factor and distance modulus using the flat ΛCDM Planck 2018 model. 4. Check the spectral-line table: The table at the bottom shows where common lines (Hα, Lyman-α, Ca K, Mg II, etc.) would fall in the observed spectrum at your redshift, and which electromagnetic band they land in. FAQ: Q: What is redshift and why does it happen? A: Redshift (z) measures how much the universe has stretched the wavelength of light since it was emitted. A photon emitted with wavelength λ₀ is observed at λ_obs = λ₀ × (1 + z). Galaxies appear redshifted because the space between us and them has expanded while the light was travelling; this is cosmological redshift, distinct from the Doppler shift caused by ordinary motion through space. Q: What is the formula for redshift? A: Redshift is defined as z = (λ_observed − λ_rest) / λ_rest = λ_observed / λ_rest − 1. Equivalently, the scale factor of the universe when the light was emitted is a = 1 / (1 + z), so z = 0.5 means the universe was two-thirds of its current size when that light set out. Q: How is recession velocity calculated from z? A: For a pure special-relativistic Doppler shift, the formula is v = c × ((z+1)^2 − 1) / ((z+1)^2 + 1). For small z this simplifies to Hubble's law v ≈ H₀ × d ≈ z × c. The relativistic form is used here so that v always stays below c regardless of z. Q: What is comoving distance and how does it differ from luminosity distance? A: Comoving distance D_C is the proper distance between two objects measured on a grid that expands with the universe — it does not change as the universe grows (assuming the objects are at rest in comoving coordinates). Luminosity distance D_L = (1 + z) × D_C is larger because cosmological expansion dims a source: the flux you receive is reduced by two factors of (1 + z), one from photon energy loss and one from arrival-rate stretching. Angular diameter distance D_A = D_C / (1 + z) is smaller and governs how large an object appears on the sky. Q: What does lookback time mean? A: Lookback time is how long ago (in billions of years) the observed light was emitted. For a galaxy at z = 1 the lookback time is about 7.7 Gyr, meaning you are seeing the galaxy as it was 7.7 billion years ago. The age of the universe when that light was emitted is 13.787 − 7.7 ≈ 6.1 Gyr. Q: What cosmological model does this calculator use? A: The calculator uses a flat ΛCDM model with the Planck 2018 best-fit parameters: Hubble constant H₀ = 67.4 km/s/Mpc, matter density Ω_m = 0.315 and dark-energy density Ω_Λ = 0.685. Distances are computed by numerical integration of the comoving distance integral using 1 000 steps; lookback time uses 2 000 steps. The CMB temperature scales as T(z) = 2.725 × (1 + z) K. #### Solar Noon Calculator URL: https://geratools.com/solar-noon-calculator Free solar noon calculator: enter latitude, longitude and date to get solar noon, sunrise, sunset, day length, golden hour windows and solar elevation. Uses the NOAA algorithm — no network required. How to use: 1. Enter your coordinates: Type your latitude (positive for north, negative for south) and longitude (positive for east, negative for west), or click a city preset to fill them automatically. 2. Pick a date: Select any date using the date picker. The calculator works for any date from 1900 to 2100. 3. Set your UTC offset: Enter the hours your local time zone is ahead of or behind UTC. For example, use +1 for Central European Time or -5 for US Eastern Standard Time. 4. Read the results: Solar noon, sunrise, sunset, day length, golden hour windows and solar elevation appear instantly. Expand the formula working section to see every intermediate step. FAQ: Q: What is solar noon and why does it differ from 12:00? A: Solar noon is the moment the sun crosses the local meridian and reaches its highest point in the sky. It rarely coincides with 12:00 on your clock because clocks are set to a fixed time-zone offset, while the sun moves continuously. Two corrections shift it - the equation of time (up to plus or minus 16 minutes, caused by the elliptical orbit and axial tilt) and the longitude difference between your location and the centre of your time zone (4 minutes per degree). Q: How accurate is the solar noon time given by this calculator? A: The calculator uses the NOAA solar position algorithm, based on Meeus (Astronomical Algorithms, 2nd edition). For dates between 1900 and 2100 the error is within about 1 minute of arc for the sun angle and within about 1 minute of time for noon and sunrise/sunset. Atmospheric refraction at the horizon adds a small additional uncertainty of around 1-2 minutes depending on weather. Q: What is the equation of time? A: The equation of time is the difference (in minutes) between apparent solar time and mean solar time. It arises because Earth moves faster when near perihelion (January) and slower near aphelion (July), and because the ecliptic is tilted relative to the equator. The combined effect produces a figure-eight analemma pattern - the sun can be up to 16 minutes ahead of or behind clock noon over the course of a year. Q: How is the golden hour calculated? A: The golden hour is defined as the period when the sun is between 0 degrees and 6 degrees above the horizon. The calculator finds the hour angle at which the solar elevation equals exactly 6 degrees using the same spherical trigonometry as the sunrise/sunset calculation, then converts that hour angle to a local time. The morning golden hour runs from sunrise until that time; the evening golden hour runs from that time until sunset. Q: What happens at polar latitudes? A: Above the Arctic Circle or below the Antarctic Circle the sun can remain continuously above or below the horizon for days or months around the solstices. When the sun never sets the calculator shows polar day and still reports solar noon and elevation. When the sun never rises it shows polar night and only the equation of time and declination are meaningful. Q: Does this calculator account for daylight saving time? A: The UTC offset field is purely manual. Enter the actual offset in effect on the chosen date - for example +2 for British Summer Time or +1 for Central European Standard Time. The calculator has no knowledge of DST transition rules, so you must apply the correct offset yourself. #### Star Magnitude Calculator URL: https://geratools.com/star-magnitude-calculator Free star magnitude calculator: compare stellar flux ratios via Pogson's formula, convert apparent to absolute magnitude with the distance modulus, combine the brightness of multiple stars, and estimate your telescope's limiting magnitude. Runs entirely in your browser. How to use: 1. Choose a calculation mode: Select Flux Ratio to compare two stars, Distance Modulus to convert between apparent and absolute magnitude, Combine Stars to find the total brightness of a group, or Limiting Magnitude to see how faint your telescope can reach. 2. Enter the values: Type apparent magnitudes, distances in parsecs, or your telescope aperture in millimetres. Results update instantly as you type. 3. Read the results: Each panel shows the computed quantity with the formula used, a visibility label, and a reference table so you can cross-check against well-known objects. FAQ: Q: What is the magnitude scale in astronomy? A: The magnitude scale runs backwards: lower numbers mean brighter objects. A magnitude-1 star is about 2.512 times brighter than a magnitude-2 star, and each 5-magnitude step is exactly 100 times in flux. The scale was formalised by Norman Pogson in 1856 to match the ancient Greek star-class system catalogued by Hipparchus. Q: What is Pogson''s formula? A: Pogson's formula relates the flux ratio of two stars to their magnitude difference: F1/F2 = 10^(-0.4 * (m1 - m2)). Equivalently, m1 - m2 = -2.5 * log10(F1/F2). A difference of exactly 1 magnitude corresponds to a flux ratio of 10^0.4 ≈ 2.512. Q: What is the difference between apparent and absolute magnitude? A: Apparent magnitude (m) is how bright a star looks from Earth. Absolute magnitude (M) is how bright it would look from a standard distance of 10 parsecs (32.6 light-years). The Sun has an apparent magnitude of -26.7 but an absolute magnitude of only +4.83, because it is so close. Rigel looks similar to Vega by eye, but its absolute magnitude is around -7 — it would be 150,000 times more luminous at the same distance. Q: How does the distance modulus work? A: The distance modulus is defined as (m - M) = 5 * log10(d / 10), where d is the distance in parsecs. At 10 pc the modulus is 0, at 100 pc it is +5, at 1 kpc it is +10, and at 1 Mpc it is +30. You can rearrange to find the distance if you know both m and M, or find M if you know m and d from parallax or Cepheid measurements. Q: Why does combining two equal stars only give 0.75 magnitudes of extra brightness? A: Because the magnitude scale is logarithmic. Two stars of magnitude 5 each contribute flux 10^(-0.4 * 5) each, so total flux is doubled. Doubling flux corresponds to -2.5 * log10(2) ≈ -0.75 magnitudes. Similarly, 100 identical stars together are only 5 magnitudes brighter than one alone, because 100 = 10^2 and -2.5 * 2 = -5. Q: What limits how faint a telescope can see? A: The limiting magnitude grows as aperture increases because a larger mirror or lens gathers more photons. The empirical formula m_lim ≈ 2.1 + 5 * log10(aperture in mm) gives a reasonable estimate under dark skies with the eye fully adapted. Urban skyglow, turbulence (seeing), eyepiece transmission losses, and the magnification used all reduce the practical limit below this theoretical ceiling. ### Geography & GPS #### Compass Deviation & Variation Correction Tool URL: https://geratools.com/compass-deviation-correction-tool Convert between true, magnetic, and compass headings or bearings by applying chart variation and deviation-card deviation with the TVMDC mnemonic. Built for navigators and sailing students doing chartwork and passage planning. How to use: 1. Pick a known heading: Choose which heading you already have — true, magnetic, or compass — and enter it in degrees from 0 to 359. 2. Enter variation and deviation: Type the chart variation and the deviation from your deviation card, each with its East or West direction. East is positive, West is negative. 3. Read every other heading: The tool applies the TVMDC rules and shows the true, magnetic, and compass equivalents along with the total compass error. FAQ: Q: What does TVMDC stand for? A: True, Variation, Magnetic, Deviation, Compass. It is the order of corrections from chart to compass. Going down the list (true to compass) you subtract easterly errors and add westerly; going up you do the reverse. Q: How do I sign variation and deviation? A: By convention East is positive and West is negative. The tool lets you pick the direction so you do not have to remember the sign. Internally it treats east errors as positive degrees and west errors as negative. Q: What is compass error? A: Compass error is the algebraic sum of variation and deviation. It is the single correction between the true heading and the compass heading. East error means the compass reads low; west error means it reads high. Q: Why does deviation change with heading? A: Deviation is caused by the vessel's own magnetic field, which points differently relative to the compass as the ship turns. That is why deviation is read from a card indexed by compass heading, not taken as a single value. Q: Which way do I apply the corrections? A: From true to compass, subtract east and add west. From compass to true, add east and subtract west. The classic memory aid is can dead men vote twice at elections, and this tool applies the rules for you so you only enter values. #### Great-Circle Aviation Route Calculator URL: https://geratools.com/great-circle-aviation-calculator Compute great-circle distance in nautical miles, initial true course, and equally spaced en-route waypoints between two latitude and longitude positions. Flight dispatchers and navigation students use it for long-haul and oceanic route construction. Runs in your browser. How to use: 1. Enter the origin coordinates: Type the latitude and longitude of the departure airport in decimal degrees, using negative values for south and west. 2. Enter the destination coordinates: Type the latitude and longitude of the arrival airport in the same decimal-degree format. 3. Choose waypoint count: Set how many equally spaced en-route waypoints to generate, then read the distance, initial true course, and waypoint table. FAQ: Q: What is a great-circle route? A: A great circle is the shortest path between two points on the surface of a sphere, which is why long flights appear to curve toward the poles on a flat map. The tool computes this shortest distance and the course you start out on along it. Q: Why does the course change along the route? A: Unlike a constant-heading rhumb line, a great circle continuously changes its true course as you travel. The tool reports the initial true course at the origin, and the waypoints let you re-check the course as you progress along the route. Q: How is the distance computed? A: It uses the haversine formula on a spherical Earth with a radius of 3440 nautical miles. This is accurate to a fraction of a percent for route planning, though precise navigation databases use a slightly flattened ellipsoid model. Q: How are the waypoints calculated? A: The tool uses spherical interpolation along the great circle, placing each waypoint at an equal fraction of the total angular distance. This gives true points on the shortest path rather than a straight line drawn on a flat chart. Q: Are these true or magnetic courses? A: The initial course is true, referenced to true north. To fly it you must apply local magnetic variation, which changes along the route, so oceanic plans often track true course and apply variation at each waypoint. #### Nautical Distance Calculator (Rhumb & Great-Circle) URL: https://geratools.com/nautical-distance-calculator Compute rhumb-line and great-circle distance in nautical miles between two latitude/longitude positions, with the initial great-circle course and the mileage saved versus the constant-heading rhumb line. Navigators and voyage planners use it for passage planning. How to use: 1. Enter the two positions: Type the latitude and longitude of the departure and arrival points in decimal degrees, with south and west as negative. 2. Pick the method to compare: Read both the great-circle (shortest) and rhumb-line (constant heading) distances side by side. 3. Read distance and course: The tool shows both distances in nautical miles, the initial great-circle course, and the mileage you save by sailing the great circle. FAQ: Q: What is the difference between rhumb line and great circle? A: A great circle is the shortest path across the curved earth but requires a constantly changing heading. A rhumb line holds a single constant compass course, which is simpler to steer but longer. The gap grows on long, high-latitude, east-west passages. Q: Why is distance measured in nautical miles? A: One nautical mile equals one minute of arc of latitude, about 1.852 kilometres. This ties distance directly to angular position on the globe, which is why marine and air navigation use it. A speed of one nautical mile per hour is one knot. Q: How is great-circle distance calculated? A: The tool uses the haversine formula on the two latitude/longitude points to get the central angle between them, multiplies by the earth's radius, then converts to nautical miles. Haversine is numerically stable even for very short distances. Q: When is the rhumb-line saving worth taking? A: On short or near north-south passages the two routes are almost identical, so the constant-heading rhumb line is fine. On long east-west ocean crossings at high latitude the great circle can save many miles and hours, justifying the course changes. Q: Does this account for land, currents, or weather? A: No. It returns the straight geodesic and constant-course distances over open water only. Real passage plans must route around land and traffic separation schemes and adjust for currents, weather routing, and draft restrictions. #### Haversine Distance Calculator URL: https://geratools.com/haversine-distance-calculator Free haversine distance calculator. Enter decimal-degree coordinates for two locations and instantly get the great-circle distance in kilometres, miles, nautical miles and metres, plus forward and reverse bearings. Runs entirely in your browser. How to use: 1. Enter coordinates for Point A: Type the latitude and longitude of your first location in decimal degrees (e.g. 51.5074, -0.1278 for London). 2. Enter coordinates for Point B: Type the latitude and longitude of your second location in decimal degrees. 3. Read the distance and bearing: The calculator instantly shows the great-circle distance in km, miles, nautical miles and metres, plus the compass bearing from A to B and from B to A. 4. Use a preset to get started quickly: Click any quick-preset button (London to New York, Sydney to Tokyo, etc.) to load example coordinates. FAQ: Q: What is the Haversine formula? A: The Haversine formula calculates the shortest distance between two points on a sphere (the great-circle distance) from their latitudes and longitudes. It is named after the haversine trigonometric function hav(theta) = sin²(theta/2). The formula is a = sin²(dLat/2) + cos(lat1)·cos(lat2)·sin²(dLon/2); c = 2·asin(sqrt(a)); d = R·c, where R is the Earth radius (6 371 km). Q: How accurate is the Haversine distance? A: It is accurate to within roughly 0.3-0.5% for any two surface points. The error arises because the Earth is an oblate spheroid, not a perfect sphere; the polar radius (6 357 km) is about 21 km shorter than the equatorial radius (6 378 km). For aviation, shipping, and most GIS applications the Haversine result is entirely sufficient. For geodetic surveying requiring millimetre precision, use Vincenty's formulae or the Karney method. Q: What is decimal-degree format? A: Decimal degrees express latitude and longitude as a single signed number rather than degrees-minutes-seconds. Latitude ranges from -90 (South Pole) to +90 (North Pole); longitude from -180 to +180 (negative = West). To convert from DMS, use decimal = degrees + (minutes / 60) + (seconds / 3600). For example, 51° 30' 26" N becomes 51.5074, and 0° 7' 40" W becomes -0.1278. Q: What is the difference between great-circle distance and straight-line distance? A: A straight-line (Euclidean) distance would pass through the Earth's interior. Great-circle distance is the shortest path along the surface of the sphere, which is the arc of a circle whose centre is the Earth's centre. For points more than a few hundred kilometres apart the difference becomes significant. Aeroplanes and ships follow great-circle routes (subject to winds and currents) because they are the shortest surface paths. Q: What do the forward and reverse bearings mean? A: The forward bearing is the initial compass direction you must travel from Point A to reach Point B (measured clockwise from true north). The reverse bearing is the initial direction from Point B back to Point A. Because Earth is curved, these two bearings are not simply 180° apart except along the equator or a meridian. For example, flying from London to New York you head roughly west-southwest (283°), but the return bearing from New York is roughly east-northeast (51°). Q: Why does the calculator use 6 371.009 km as the Earth radius? A: 6 371.009 km is the International Union of Geodesy and Geophysics (IUGG) mean radius, defined as the arithmetic mean of the equatorial and two polar radii. It is the standard reference radius for single-sphere approximations and is used by most navigation software, Google Maps distance calculations, and the OpenLayers mapping library. #### Latitude & Longitude Converter URL: https://geratools.com/latitude-longitude-converter Free latitude and longitude converter. Paste any coordinate format — decimal degrees, degrees-minutes-seconds, DDM, radians — and instantly get all other formats, the UTM grid reference, great-circle distance between two points, and forward/return bearing. Runs entirely in your browser. How to use: 1. Paste or type a coordinate: Enter latitude and longitude in any supported format — decimal degrees, DMS, DDM, or radians. The tool auto-detects the format. 2. Choose your output format: Pick Decimal Degrees, Degrees & Decimal Minutes, DMS, Radians, or approximate UTM from the dropdown. 3. Copy the result: Click Copy next to any output value, or expand the full table to copy all formats at once. 4. Calculate distance between two points: Switch to the Distance & Bearing tab, enter a second coordinate, and get the Haversine great-circle distance in km, miles, and nautical miles plus the forward and return bearing. FAQ: Q: What is the difference between DD, DDM, and DMS? A: All three express the same location on Earth using degrees. Decimal Degrees (DD) uses a single floating-point number per axis — e.g. 51.5074° N. Degrees and Decimal Minutes (DDM) splits that into whole degrees plus a decimal fraction of minutes — e.g. 51° 30.444' N. Degrees Minutes Seconds (DMS) goes one step further and gives whole degrees, whole minutes, and a decimal fraction of seconds — e.g. 51° 30' 26.64" N. GPS receivers typically output DDM; mapping software usually stores DD; old paper charts use DMS. Q: How do I convert decimal degrees to DMS? A: Take the absolute value of the decimal degree. The integer part is the degrees. Multiply the decimal remainder by 60 — the integer part of that is the minutes. Multiply the decimal remainder of the minutes by 60 — that gives the seconds. Assign N/S for latitude (positive = N) and E/W for longitude (positive = E). Example: 51.5074° = 51° + (0.5074 × 60)' = 51° 30' + (0.444 × 60)" = 51° 30' 26.64" N. Q: What is the Haversine formula? A: The Haversine formula computes the shortest path between two points on a sphere (great-circle distance). Given latitudes phi_1, phi_2 and longitudes lambda_1, lambda_2 (all in radians): a = sin²((phi_2 - phi_1)/2) + cos(phi_1) · cos(phi_2) · sin²((lambda_2 - lambda_1)/2), then d = 2R · asin(sqrt(a)), where R is the mean Earth radius (6371.0088 km). It is accurate to within 0.3 % for most purposes; Vincenty's formula is more precise for near-antipodal points. Q: What is bearing and how is it measured? A: Bearing is the horizontal direction from one point to another, measured clockwise from true North (0°) to 360°. A bearing of 090° means due East; 180° means due South. The forward bearing is from Point A to Point B; the return bearing is the direction you would travel going back. They are supplementary — roughly 180° apart — but not exactly because the Earth is spherical. Q: What is UTM and is the converter accurate? A: UTM (Universal Transverse Mercator) is a grid coordinate system that divides the Earth into 60 north-south zones, each 6° wide, numbered 1–60 East. Within each zone, positions are given as Easting (metres east of the zone's central meridian, offset by 500,000 m to keep positive) and Northing (metres north of the Equator, with a 10,000,000 m false northing in the Southern Hemisphere). This tool uses the standard series-expansion formula for WGS-84 and is accurate to within 1 metre for latitudes below 80°. It is not suitable for high-precision surveying at extreme latitudes. Q: What coordinate formats does the converter accept? A: The parser accepts: plain decimal degrees (51.5074 or -0.1278), decimal degrees with direction suffix (51.5074N or 0.1278W), DMS with degree/minute/second symbols (51° 30' 26.6" N), DDM (51° 30.444' N), colon-separated DMS (51:30:26.6N), and radians with an 'r' or 'rad' suffix (0.8988rad). Positive values default to N/E; negative to S/W. #### Bearing Calculator URL: https://geratools.com/bearing-calculator Free bearing calculator using the Haversine formula. Enter two sets of coordinates (latitude/longitude) and instantly get the forward bearing, back bearing, great-circle distance in km/miles/nautical miles, midpoint and a compass rose. 100% client-side. How to use: 1. Enter the origin coordinates: Type the latitude and longitude of Point A in decimal degrees. Positive latitude is North, negative is South. Positive longitude is East, negative is West. 2. Enter the destination coordinates: Type the latitude and longitude of Point B. The tool converts your decimal degrees to degrees-minutes-seconds (DMS) in real time as a sanity check. 3. Read the forward bearing: The forward bearing (in degrees, 0-360) and 16-point compass direction (N, NNE, NE, etc.) appear immediately. This is the heading you face at A to follow the great-circle path to B. 4. Note the back bearing and distance: The back bearing is the arrival heading at B -- useful for planning a return leg. The distance is shown in kilometres, miles and nautical miles. 5. Check the midpoint: The great-circle midpoint coordinates are shown in decimal degrees and DMS, useful for planning a waypoint or fuel stop. FAQ: Q: What is a compass bearing? A: A compass bearing is the horizontal angle measured clockwise from True North (0°) to the direction of travel. It ranges from 0° to 359°. Due North is 0°, due East is 90°, due South is 180° and due West is 270°. Q: What is the difference between forward and back bearing? A: The forward bearing is the compass heading at the origin pointing toward the destination. The back bearing (also called the reciprocal or reverse bearing) is the heading from the destination back to the origin -- approximately 180° different, though on a curved Earth surface the difference is not exactly 180° for long routes. Q: Why does this calculator use the Haversine formula? A: The Haversine formula computes the shortest path between two points on a sphere (a great-circle route). It handles the curvature of the Earth, antipodal points and the International Date Line correctly. The formula is: a = sin²(Δφ/2) + cos φ1 · cos φ2 · sin²(Δλ/2); d = 2R · arcsin(√a), where φ is latitude, λ is longitude and R is Earth radius (6 371 km). Q: How accurate is the Haversine distance? A: The Haversine formula assumes a perfect sphere with radius 6 371 km. Earth is actually a slightly flattened oblate spheroid, so the maximum error is about 0.3% compared to the more precise Vincenty formula. For navigation, hiking, aviation planning and most engineering purposes the Haversine result is more than adequate. Q: What are decimal degrees and how do I convert from DMS? A: Decimal degrees (DD) express latitude/longitude as a single number, e.g., 51.5074°. Degrees-minutes-seconds (DMS) uses 51° 30' 26.64" N. To convert: DD = degrees + (minutes / 60) + (seconds / 3600). The calculator shows the DMS equivalent live as you type. Q: What is a great-circle route? A: A great circle is the largest circle that can be drawn on a sphere, passing through two points and the centre of the sphere. The great-circle route is the shortest path between two points on the surface of the Earth. Aircraft and ships follow great-circle routes to minimise fuel and time. #### Compass Bearing Calculator URL: https://geratools.com/compass-bearing-calculator Free compass bearing calculator. Enter two GPS coordinates to get the forward bearing, final bearing, great-circle distance (km/mi/NM), midpoint, and a live compass rose. Or work backwards: give a starting point, heading and distance to find your destination. Runs entirely in your browser — no data uploaded. How to use: 1. Enter Point A coordinates: Type the latitude and longitude of your starting location in decimal degrees (e.g. 51.5074, -0.1278) or DMS format (e.g. 51° 30' N). 2. Enter Point B coordinates: Type the latitude and longitude of your destination. The forward bearing, final bearing, and great-circle distance update instantly. 3. Read the compass rose: The animated compass rose shows the forward bearing as a blue needle pointing toward your destination. The degree value and 16-point compass label (N, NNE, NE…) appear directly on the dial. 4. Use the Find Destination tab: Switch to the "Find Destination" tab, enter your starting point, a bearing in degrees, and a travel distance (km, mi, or NM) to calculate exactly where you will end up. 5. Copy or share the result: Click "Copy results" to put the bearing, distance, and midpoint on your clipboard as plain text. FAQ: Q: What is compass bearing? A: A compass bearing is the horizontal angle measured clockwise from true north (0°) to a direction. A bearing of 0° means due north, 90° is due east, 180° is due south, and 270° is due west. Bearings above 315° are northwest. The 16-point compass system subdivides these into finer directions such as NNE (22.5°), ENE (67.5°), and so on. Q: What is the difference between forward bearing and final bearing? A: The forward bearing (also called the initial bearing) is the compass heading you face at point A to begin a great-circle path to point B. Because the Earth is curved, the heading continuously changes along that path. The final bearing is the compass heading at which you arrive at point B — it is equivalent to the reverse bearing from B back to A, plus 180°. For long-haul flights over thousands of kilometres the two values can differ by tens of degrees. Q: What is the Haversine formula, and why does this calculator use it? A: The Haversine formula computes the great-circle distance between two points on a sphere from their latitudes and longitudes: a = sin²(Δφ/2) + cos φ₁ · cos φ₂ · sin²(Δλ/2); d = 2R · arcsin(√a). It is numerically stable even for very short distances (unlike the simpler spherical law of cosines) and is accurate to within roughly 0.5% for any pair of surface points. The maximum error occurs near the poles where the Earth is slightly flattened; for most navigation purposes the formula is fully sufficient. Q: What does "true north" mean, and how does it differ from magnetic north? A: True north points toward the geographic North Pole — the axis of the Earth's rotation. Magnetic north, by contrast, is where a compass needle points, which is currently about 500 km from the geographic pole and shifts several kilometres every year. This calculator outputs bearings relative to true north. To use the result with a magnetic compass, subtract (or add) the local magnetic declination for your location, which can be looked up from resources such as NOAA's magnetic declination calculator. Q: How do I enter coordinates in DMS format? A: The input fields accept both decimal degrees (e.g. 48.8566) and degrees-minutes-seconds strings (e.g. "48° 51' 24" N" or "48 51 24 N"). Negative decimal values represent south latitudes and west longitudes; if you enter a direction letter (N/S/E/W) the sign is applied automatically. Q: How accurate is the destination-point calculation? A: The destination-point formula uses spherical trigonometry: φ₂ = arcsin(sin φ₁ · cos(d/R) + cos φ₁ · sin(d/R) · cos θ) and λ₂ = λ₁ + atan2(sin θ · sin(d/R) · cos φ₁, cos(d/R) − sin φ₁ · sin φ₂). It assumes a perfectly spherical Earth with radius 6 371.009 km. Real-world accuracy is within about 0.3% for any distance; for precision maritime or aviation navigation an ellipsoidal model (Vincenty or Karney) would give sub-metre results. #### Coordinate Distance Calculator URL: https://geratools.com/coordinate-distance-calculator Free coordinate distance calculator. Enter two latitude/longitude pairs to get the straight-line (great-circle) distance in kilometres, miles and nautical miles, plus the forward and return bearings and the geographic midpoint. Uses the Haversine formula. Runs entirely in your browser — no data is sent to a server. How to use: 1. Enter the first coordinate: Type or paste the latitude and longitude for Point A in decimal degrees (e.g. 51.5074, -0.1278). Or choose a city from the preset list to fill the fields automatically. 2. Enter the second coordinate: Do the same for Point B. Negative latitude means south of the equator; negative longitude means west of the prime meridian. DMS format such as 40° 26' 46" N is also accepted. 3. Read the results: The calculator instantly shows the great-circle distance in km, miles and nautical miles, the initial bearing from A to B, the return bearing from B to A, and the geographic midpoint between the two locations. 4. Check the step-by-step working: Click "Show step-by-step working" to see every intermediate value in the Haversine calculation — useful for verifying against your own implementation or coursework. FAQ: Q: What is the Haversine formula? A: The Haversine formula calculates the shortest path (great-circle arc) between two points on a sphere. Given latitudes φ₁ and φ₂, and the longitude difference Δλ, it first computes a = sin²(Δφ/2) + cos(φ₁)·cos(φ₂)·sin²(Δλ/2), then the central angle c = 2·asin(√a), and finally the distance d = R·c where R = 6 371 km is the mean Earth radius. The name comes from the trigonometric identity hav(θ) = sin²(θ/2). Q: How accurate is this calculator? A: The Haversine result is accurate to within about 0.5% for most distances on Earth because it models the Earth as a perfect sphere. For the highest accuracy over long baselines, geodesists use the Vincenty formula or Karney's algorithm on the WGS-84 ellipsoid, which reduce the error to sub-millimetre precision. For aviation, navigation and everyday use Haversine is more than sufficient. Q: What do positive and negative coordinates mean? A: Latitude is positive for north (0° to 90° N) and negative for south (0° to -90° S). Longitude is positive for east (0° to 180° E) and negative for west (0° to -180° W). So London is approximately 51.5° N, -0.13° W, expressed as 51.5074, -0.1278 in decimal degrees. Q: Can I enter coordinates in degrees-minutes-seconds (DMS)? A: Yes. The calculator accepts formats such as "40° 26' 46.302" N" or "40:26:46.302N". For negative (south/west) values include a minus sign or the S/W suffix. Decimal degrees like 40.4462 are also accepted and are the most common format exported by GPS devices and mapping apps. Q: What is the bearing and why are forward and return bearings different? A: The bearing is the compass direction you would travel at the starting point to follow the great-circle arc. The forward bearing is the direction from A to B; the return bearing is the direction from B back to A. They differ because great-circle paths curve across the globe — the path from London to New York heads roughly north-west but arrives heading south-west, so the return bearing is not simply 180° opposite the outgoing one (except along the equator or meridians). Q: What is the geographic midpoint? A: The geographic midpoint is the point equidistant along the great-circle arc between A and B. It is calculated by converting both points to 3-D Cartesian vectors, averaging them, and converting back to latitude/longitude. For routes that do not cross the anti-meridian (180°) this gives an intuitive point on the Earth's surface roughly halfway between the two cities. #### GPS Coordinate Formatter URL: https://geratools.com/gps-coordinate-formatter Free GPS coordinate formatter and converter. Paste any latitude/longitude in decimal degrees, DDM or DMS and instantly see all eight standard formats: DD, DDM, DMS, Geohash, Open Location Code (Plus Code), UTM, Maidenhead and MGRS. 100% client-side — nothing is uploaded. How to use: 1. Choose your input format: Select DD (decimal degrees), DDM (degrees decimal minutes) or DMS (degrees minutes seconds) to match the coordinates you have. 2. Enter your coordinates: Type the latitude and longitude into the separate fields, or paste a full coordinate pair (comma-separated or space-separated) into the pair field. 3. Read all eight output formats: The results panel shows DD, DDM, DMS, Geohash, Plus Code, UTM, Maidenhead and MGRS simultaneously — click Copy next to any row to copy it to your clipboard. 4. Open in Google Maps: Tap the "Open in Google Maps" link to verify the location visually in a new tab. FAQ: Q: What is the difference between DD, DDM and DMS? A: All three express the same location in WGS-84, just in different notations. DD (decimal degrees) stores the fractional part as a decimal — e.g. 51.507400° N. DDM keeps whole degrees and expresses the remainder as decimal minutes — e.g. 51° 30.4440' N. DMS splits into whole degrees, whole minutes and decimal seconds — e.g. 51° 30' 26.64" N. GPS receivers and mapping APIs tend to use DD; marine and aviation charts prefer DDM; traditional topographic maps use DMS. Q: What is a Geohash and when should I use it? A: A Geohash encodes a latitude/longitude pair as a short base-32 string (e.g. gcpvj0). Each additional character roughly halves the bounding-box area. This makes geohashes ideal for proximity searches in databases — rows that share a prefix are geographically close — and for tile-based caching where a short string is easier to store than two floating-point columns. Q: What is an Open Location Code (Plus Code)? A: Open Location Code (OLC), branded by Google as Plus Codes, is an open standard from Google that encodes a rectangular area into a short alphanumeric string such as 9C3XGV8F+3F. A 10-character full code identifies an area of roughly 14 × 14 metres. The format is designed for places that have no street address — you can share a Plus Code verbally or via SMS without a map link. Q: How accurate is the UTM output? A: The UTM conversion uses the full WGS-84 ellipsoid parameters (a = 6,378,137 m, 1/f = 298.257223563) and the standard transverse Mercator projection with scale factor k0 = 0.9996. Sub-metre accuracy is expected for points well within a 6-degree UTM zone. Points near zone boundaries may carry slightly higher errors due to the projection's distortion model. Q: What is a Maidenhead locator and who uses it? A: The Maidenhead Locator System (also called the QRA locator) is a geographic coordinate system used by amateur (ham) radio operators worldwide. A 6-character code like IO91wm identifies a 2.5'' × 5'' cell (roughly 4 km × 4 km at mid-latitudes). Operators exchange locators during radio contacts to calculate distance and beam headings, and contest logs always include them. Q: Is my location data private? A: Yes. Every calculation runs locally in your browser using JavaScript. No coordinates are sent to any server, logged, or stored anywhere outside your device. You can use this tool offline once the page has loaded. #### Great-Circle Distance Calculator URL: https://geratools.com/great-circle-distance-calculator Free great-circle distance calculator. Enter two sets of decimal-degree coordinates to get the shortest surface distance in km, miles, and nautical miles, plus forward and return bearings, the midpoint, and a side-by-side Haversine vs Vincenty comparison. Runs entirely in your browser. How to use: 1. Enter two coordinate pairs: Type the latitude and longitude (decimal degrees) for Point A and Point B. Use negative values for south latitudes and west longitudes. 2. Choose a formula: Leave the checkbox off for Haversine (spherical Earth, fast, within 0.5%). Tick it for Vincenty (WGS-84 ellipsoid, sub-millimetre accuracy for any non-antipodal pair). 3. Read the results: The tool shows distance in km, miles, and nautical miles; forward and reverse bearings on animated compass roses; the geographic midpoint; and an estimated flight time and walking time for context. 4. Inspect the working: Expand "Show step-by-step working" to see every intermediate value including the Haversine a and c values and the Vincenty ellipsoidal correction in metres. FAQ: Q: What is a great-circle distance? A: A great circle is the largest possible circle that can be drawn on a sphere — its plane passes through the centre of the sphere. The arc of a great circle connecting two surface points is the shortest possible route between them, which is why transoceanic flights appear curved on flat maps but are actually the straight-line path on the globe. Q: What is the Haversine formula? A: The Haversine formula computes the central angle c between two points using a = sin²(Δφ/2) + cos(φ₁)·cos(φ₂)·sin²(Δλ/2) and then c = 2·asin(√a). Multiplying c by the mean Earth radius gives the arc length. It is numerically stable for small distances (unlike the spherical law of cosines) and accurate to within roughly 0.5% because it treats the Earth as a perfect sphere. Q: What is the Vincenty formula and when should I use it? A: Vincenty (1975) iteratively solves the geodesic on the WGS-84 oblate spheroid — the same reference ellipsoid used by GPS. It converges to sub-0.5 mm accuracy for virtually any pair of points. Use it when you need survey-grade precision, when comparing to GPS measurements, or when working near the poles where the Earth deviates most from a sphere. For casual navigation or flight planning, Haversine is perfectly adequate. Q: What are forward and reverse bearings? A: The forward bearing is the initial compass heading you would set off on from Point A to travel the great-circle route to Point B, measured clockwise from north (0°–360°). Because the route curves on a globe, by the time you arrive at Point B the bearing has changed — the reverse bearing is the heading from B back to A, which is not simply 180° plus the forward bearing except along the equator. Q: How accurate is this calculator? A: Haversine mode is accurate to within about 0.5% (roughly 5 km on a 1,000 km route) because it uses a sphere with the IUGG mean radius of 6,371.009 km. Vincenty mode achieves better than 0.5 mm accuracy by modelling the WGS-84 ellipsoid. Neither accounts for terrain elevation, so actual travel distances over mountains or valleys will be greater. Q: Can I use degrees, minutes, and seconds instead of decimal degrees? A: This tool accepts decimal degrees only. To convert from DMS, use the formula decimal = degrees + minutes/60 + seconds/3600. For example, 51° 30′ 26.65″ N converts to 51 + 30/60 + 26.65/3600 = 51.5074°. #### Map Scale Calculator URL: https://geratools.com/map-scale-calculator Free map scale calculator. Convert map distance to real-world distance, real-world to map, or derive an unknown scale from two known measurements. Supports mm, cm, m, km, inches, feet, yards, miles and nautical miles. Includes area scaling and a quick-reference table for common map scales. How to use: 1. Choose what to solve for: Pick "Real-world distance", "Map distance", or "Find scale" using the tabs at the top. 2. Select a map scale: Choose a preset (1:25,000 OS Explorer, 1:50,000 OS Landranger, etc.) or enter a custom ratio. 3. Enter the known measurement: Type the distance you already know — on the map or in the real world — and choose its unit. 4. Choose your output unit: Pick the unit you want the answer displayed in (metres, kilometres, miles, etc.). 5. Read the result and working: The highlighted row shows the answer; the working panel below shows every step of the arithmetic. 6. Use the area converter: Expand the "Area converter" section to find the real-world area covered by a square on the map. FAQ: Q: What does a 1:50,000 scale mean? A: 1:50,000 means that one unit on the map represents 50,000 of the same unit in the real world. So 1 cm on the map equals 50,000 cm, which is 500 m or 0.5 km. The Ordnance Survey Landranger series uses exactly this scale. Q: How do I convert a map distance to real-world kilometres? A: Multiply the map measurement (in cm) by the scale denominator, then divide by 100,000 to convert centimetres to kilometres. For a 1:50,000 map, 3 cm (times) 50,000 = 150,000 cm = 1.5 km. This calculator does all that arithmetic for any unit combination. Q: How does area scaling work on a map? A: Area scales as the square of the linear scale factor. On a 1:50,000 map, 1 cm on the map is 500 m in reality, so 1 cm(squared) on the map equals 500 m (times) 500 m = 250,000 m(squared) = 0.25 km(squared). Use the "Area converter" panel to compute this automatically. Q: How do I find an unknown map scale? A: Switch to "Find scale" mode, then enter both a map measurement and the known real-world distance it corresponds to. The calculator divides the real-world distance by the map distance (both converted to metres first) to derive the scale ratio. Q: Which scale is best for hiking: 1:25,000 or 1:50,000? A: 1:25,000 (OS Explorer) shows more detail — field boundaries, footpaths, crags — and is preferred for on-foot navigation. 1:50,000 (OS Landranger) covers a larger area per sheet and is better for planning longer routes or cycling where the extra detail is less important. Q: Can I use this for nautical charts? A: Yes. Select "nmi (nautical miles)" as your unit. Nautical charts use a range of scales from 1:5,000 (harbour approach) to 1:3,500,000 (ocean passage planning). The calculator supports all of these — just enter the scale and your charted distance in any unit. #### UTM Coordinate Converter URL: https://geratools.com/utm-coordinate-converter Free UTM coordinate converter. Convert any WGS-84 latitude/longitude pair to a UTM easting, northing and zone — or reverse any UTM grid reference back to decimal degrees and DMS. Full Transverse Mercator math, 100% in your browser. How to use: 1. Choose the conversion direction: Click "Lat/Lon to UTM" to convert geographic coordinates, or "UTM to Lat/Lon" to decode a grid reference. 2. Enter your coordinates: For Lat/Lon mode type the decimal-degree latitude (negative = south) and longitude (negative = west). For UTM mode enter the zone number (1–60), hemisphere, easting and northing in metres. 3. Read the results: The converted coordinates appear instantly below the inputs, including DMS notation and the full UTM zone letter. Click Copy to copy the result. FAQ: Q: What is UTM and why is it used? A: UTM (Universal Transverse Mercator) is a cylindrical map projection that divides the Earth into 60 north–south zones each 6° wide. Unlike geographic latitude/longitude, UTM gives you flat Cartesian metre coordinates, so you can measure straight-line distances and areas with simple arithmetic. It is the coordinate system used on most topographic maps, GPS receivers, military grid references (MGRS), and GIS software. Q: How accurate is the conversion? A: The tool implements the full Transverse Mercator series expansion from USGS Professional Paper 1395 (Snyder 1987). Within the standard UTM valid region — up to ±3° from the central meridian — accuracy is sub-millimetre. Accuracy degrades smoothly for points farther from the central meridian, but the projection is rarely used there in practice. Q: What is the difference between easting, northing and zone? A: The zone number (1–60) tells you which 6° longitude band the point lies in. The easting is the distance in metres east of a false origin set 500 000 m west of the central meridian, so it is always between roughly 100 000 m and 900 000 m. The northing is the distance in metres north of the equator (northern hemisphere) or of a false origin 10 000 000 m south of the equator (southern hemisphere), ensuring the northing is always positive. Q: What does the zone letter mean? A: The UTM latitude band letter (C through X, skipping I and O) divides each zone into 8° latitude bands. Together with the zone number it is sometimes written as a single grid designator, e.g. "30U" for London. The letter is purely informational in this tool — the actual projection uses the hemisphere (N/S) switch, not the letter, to determine the false northing. Q: Does this tool handle the special zones around Norway and Svalbard? A: Yes. The converter applies the standard exceptions defined in the UTM specification. Zone 32 is extended westward to cover southwest Norway (56°N–64°N, 3°E–12°E), and four irregular zones (31, 33, 35, 37) cover Svalbard above 72°N so that the ice-cap landmass is not split across zone boundaries. Q: Can I use this for MGRS (military grid) coordinates? A: MGRS builds on UTM by adding a 100 km grid square letter pair on top of the zone designator. This tool gives you the UTM zone, easting and northing — you can then look up the 100 km square identifier in a standard MGRS table. Full MGRS encoding (square lookup) is outside this tool's scope, but the UTM output is the correct input for MGRS converters. ### Statistics & Probability #### Catan Dice Roll Probability Analyzer URL: https://geratools.com/catan-resource-probability Enter the hex numbers and resources a Catan settlement touches to compute production probability per resource using the 2d6 distribution and pip counts. Optimize starting placement and trade strategy in Settlers of Catan. How to use: 1. Add the touching hexes: Add the one to three hexes your settlement or city corner touches, choosing each hex's dice number from the dropdown. 2. Tag the resources: Set each hex's resource type so the tool can break production down by brick, lumber, wool, grain, and ore. 3. Read the odds: See the total pip count, expected cards per roll, and a per-resource probability table to compare placements. FAQ: Q: How are Catan number probabilities calculated? A: Two six-sided dice produce each number a fixed number of ways out of 36: 6 and 8 have five ways (the best), while 2 and 12 have only one. The probability of a number is its number of ways divided by 36. Q: What are pips and why do they matter? A: Pips are the dots printed under each number token and equal the number of ways to roll it on 2d6. Adding the pips of the hexes a spot touches gives a quick strength score — more pips means more frequent production. Q: Why is 7 excluded? A: Rolling a 7 triggers the robber and produces no resources, so no hex ever carries a 7 token. The tool only offers the producing numbers 2 to 6 and 8 to 12. Q: How many hexes can a settlement touch? A: A settlement or city sits on a corner where up to three hexes meet, so you can add one, two, or three hexes. Cities produce two cards per hit instead of one, doubling the expected yield. Q: What counts as a strong starting spot? A: A strong opening corner usually totals 10 to 12 pips across its hexes, ideally including a 6 or 8 and a spread of resources. Weak corners total only 3 to 5 pips and produce rarely. #### Motor KV & Propeller Combination Calculator URL: https://geratools.com/motor-kv-prop-calculator Enter motor KV, cell count in series, and propeller diameter and pitch to compute theoretical unloaded RPM, propeller tip speed, and an estimated pitch speed. For RC plane and multirotor builders selecting motors and props. How to use: 1. Enter motor KV and cell count: Type the motor's KV rating and the number of LiPo cells in series (S), which sets the pack voltage. 2. Enter prop diameter and pitch: Enter the propeller diameter and pitch in inches, the two numbers printed on the prop such as 5x4.3. 3. Read RPM and speeds: The tool shows theoretical unloaded RPM, propeller tip speed, and a rough pitch (forward) speed to help you judge the combination. FAQ: Q: How is RPM calculated from KV? A: KV is RPM per volt with no load. Theoretical RPM equals KV times pack voltage, where voltage is the cell count times the nominal 3.7 volts per cell. A 2400 KV motor on a 4S pack (14.8 V) spins about 35,500 RPM unloaded. Q: Why is real RPM lower than this number? A: KV-based RPM is the no-load figure. A propeller loads the motor and pulls voltage down under current, so actual in-flight RPM is typically 70 to 85 percent of the theoretical value. Use this number for comparison, not as an exact spec. Q: What is propeller tip speed and why does it matter? A: Tip speed is how fast the blade tips travel and equals pi times diameter times RPM. Very high tip speeds approach the speed of sound, becoming inefficient and noisy. Keeping tip speed reasonable is a key constraint when pairing high KV with large props. Q: What does pitch speed estimate? A: Pitch speed is the theoretical forward speed if the prop screwed through air with no slip, equal to pitch times RPM. Real airspeed is lower due to slip, but pitch speed gives a useful upper bound for plane top speed. Q: How do I avoid burning out a motor with the wrong prop? A: Too much prop (large diameter or pitch) on a high-KV motor draws excessive current and overheats the motor and ESC. Lower KV motors swing bigger props efficiently; high KV pairs with small props. Always check current draw against your ESC and battery limits. #### Pokémon Prize Card Probability URL: https://geratools.com/pokemon-prize-card-probability Enter how many copies of a card your Pokémon TCG deck runs and calculate the probability that one or more end up among your 6 prize cards. Evaluate deck consistency risk with exact hypergeometric math — runs entirely in your browser. How to use: 1. Enter deck and prize counts: Type your deck size (usually 60) and the number of prize cards (usually 6). 2. Enter copies of the card: Type how many copies of the card your deck runs — for example, 2 copies of a key Trainer. 3. Read the prized odds: The tool shows the probability at least one copy is prized, none are prized, all are prized, and the expected number prized. FAQ: Q: What does prized mean in the Pokémon TCG? A: At the start of a Pokémon game each player sets aside 6 cards face-down as prizes, which they take one at a time by knocking out the opponent's Pokémon. A prized card is unavailable until you take that prize, so important singletons getting prized can disrupt your strategy. Q: How is the prize probability calculated? A: The 6 prizes are a random sample drawn without replacement from your 60-card deck, so the number of copies of a card among them follows the hypergeometric distribution. The chance at least one is prized is one minus the chance none are prized. Q: How likely is a single copy to be prized? A: With one copy in a 60-card deck and 6 prizes, the chance it is prized is exactly 6 divided by 60, or 10%. The calculator generalizes this to any number of copies, deck size, and prize count. Q: Why does running more copies reduce prize risk? A: With more copies in the deck, the chance that every single copy lands in the prizes drops sharply. For instance, the odds that both copies of a two-of are prized is far lower than 10%, which is why important cards are often run as multiples. Q: What is the expected number prized? A: The expected number of copies in your prizes is simply copies times prizes divided by deck size. For a two-of in a 60-card deck that is 2 times 6 over 60, or 0.2 cards on average prized per game. #### RuneScape 3 Drop Rate & Probability Calculator URL: https://geratools.com/runescape-3-drop-rate-calculator Enter a RuneScape 3 drop rate as a 1-in-N chance and the number of kills or attempts to compute the at-least-once probability, expected number of drops, and the dry-streak odds using the correct binomial probability model. How to use: 1. Enter the drop rate: Type the rarity as a 1-in-N value, for example 5000 for a one in five thousand drop, taken from the wiki drop table. 2. Enter attempts: Type how many kills, opens, or attempts you plan to make or have already made. 3. Read the probabilities: The tool shows the chance of at least one drop, the expected number of drops, and the probability you still have nothing after that many attempts. FAQ: Q: How is at-least-once probability calculated? A: Each attempt independently succeeds with probability p equals 1 divided by N. The chance of getting nothing in n attempts is (1 minus p) to the power n, so the chance of at least one drop is 1 minus that. This is the correct geometric or binomial result, not n times p. Q: Why isn't the chance just attempts divided by drop rate? A: Multiplying attempts by p overcounts because it ignores the possibility of multiple drops and exceeds 100 percent past N attempts. The real formula 1 minus (1 minus p) to the power n caps correctly at just under 100 percent and accounts for repeated successes. Q: What does the dry-streak figure mean? A: It is the probability that after your entered number of attempts you still have zero of the item. At exactly N attempts on a 1-in-N drop this is about 36.8 percent, which is why being dry past the drop rate is completely normal. Q: How many attempts give a 50 percent chance? A: Roughly 0.693 times N attempts gives a 50 percent cumulative chance, because that is N times the natural log of 2. For a 1-in-5000 drop, about 3,466 attempts puts you at even odds of having it. Q: Is the expected number of drops the same as guaranteed? A: No. Expected drops is attempts times p, the long-run average. An expected value of 1 still leaves about a 37 percent chance of zero drops, because outcomes vary around the average. Nothing is guaranteed until the item actually drops. #### Combinations & Permutations Calculator URL: https://geratools.com/combinations-permutations-calculator Free combinations and permutations calculator — work out nCr (combinations), nPr (permutations), and factorials. All math runs locally in your browser with nothing uploaded. How to use: 1. Pick a mode: Choose combinations (nCr), permutations (nPr), or factorial from the dropdown. 2. Enter n and r: Type the total number of items n, and the number chosen r for combinations or permutations. 3. Read the result: The exact count updates instantly with thousands separators for readability. FAQ: Q: What is the difference between combinations and permutations? A: Permutations count arrangements where order matters (nPr), while combinations count selections where order does not matter (nCr). For the same n and r, nPr is always greater than or equal to nCr. Q: How is nCr calculated? A: nCr equals n! divided by r!(n − r)!. This calculator computes it iteratively to avoid overflow on larger numbers. Q: What is 10 choose 3? A: nCr(10, 3) = 120. There are 120 ways to choose 3 items from 10 when order does not matter. The matching permutation nPr(10, 3) is 720, since order does matter there. Q: What does n! (factorial) mean? A: A factorial is the product of all positive integers up to n. For example 5! = 5 × 4 × 3 × 2 × 1 = 120. It counts the number of ways to arrange n distinct items in order. Q: Is anything sent to a server? A: No — all calculations run entirely in your browser. Nothing is uploaded. #### Permutation and Combination Calculator URL: https://geratools.com/permutation-combination-calculator Free permutation and combination calculator. Enter n and r to get nPr and nCr instantly, with the factorial working shown step by step and exact BigInt results that never overflow. Runs entirely in your browser. How to use: 1. Enter n (the total number of items): Type how many distinct items you are choosing from into the n field. 2. Enter r (how many you choose): Type how many items you are arranging or selecting. r must be between 0 and n. 3. Read nPr and nCr with the working: The tool shows permutations (order matters) and combinations (order ignored), the substituted formula, and the exact factorial breakdown computed with BigInt. FAQ: Q: What is the difference between a permutation and a combination? A: A permutation counts ordered arrangements, so ABC and CBA are different. A combination counts unordered selections, so ABC and CBA are the same group. That is why nPr is always greater than or equal to nCr — for any chosen set of r items there are r! ways to order them. Q: How is nPr calculated? A: The permutation formula is nPr = n! / (n − r)!. It is the product of the r largest factors of n!, namely n × (n−1) × … × (n−r+1). For example 10P3 = 10 × 9 × 8 = 720. Q: How is nCr calculated? A: The combination formula is nCr = n! / (r! · (n − r)!), also written as "n choose r" or the binomial coefficient C(n, r). It equals nPr divided by r!. For example 10C3 = 720 / 3! = 720 / 6 = 120. Q: Why use this calculator instead of a normal one for large numbers? A: Factorials grow explosively — 21! already exceeds the largest integer a standard calculator stores exactly, so it silently rounds. This tool uses JavaScript BigInt for every step, so values like 52C5 or 100P10 are exact to the last digit with no floating-point error. Q: What happens when r is 0 or equals n? A: By convention 0! = 1, so nP0 = nC0 = 1 (there is exactly one way to choose nothing) and nCn = 1 (one way to choose everything). nPn = n!, the number of ways to arrange all n items. Q: Is my data kept private? A: Yes. Every calculation runs locally in your browser using built-in BigInt math. No numbers are sent to any server, logged, or stored. #### Kelly Criterion Calculator URL: https://geratools.com/kelly-criterion-calculator Free Kelly Criterion calculator. Enter your win probability and odds to get the exact Kelly fraction, fractional Kelly wager, edge, and log-growth rate. Supports decimal, fractional, and American odds, plus the continuous investment formula and a multi-bet portfolio table. Runs entirely in your browser. How to use: 1. Choose a mode: Select "Betting / Trading" for discrete odds (sports bets, poker, trading) or "Investment (Continuous)" for portfolio allocation using expected return and standard deviation. 2. Enter your edge inputs: Type your estimated win probability (%) and the odds you are receiving. Use the format selector to switch between decimal, fractional, or American odds. 3. Set a fractional Kelly: Drag the slider to choose what fraction of full Kelly to apply — 25% to 50% is standard practice to reduce variance while preserving most of the growth rate. 4. Read the optimal wager: The calculator shows full Kelly (f*), your fractional Kelly, and the exact wager amount for your bankroll. A live SVG chart plots the log-growth curve so you can see how over- or under-betting destroys returns. 5. Use the multi-bet table: Switch to "Multi-bet portfolio" to enter several simultaneous bets. The table computes each Kelly fraction independently and warns you if total allocation exceeds 100%. FAQ: Q: What is the Kelly Criterion formula? A: The Kelly Criterion states the optimal fraction f* of your bankroll to bet is f* = (b·p − q) / b, where b is the net decimal odds (decimal odds minus 1), p is the probability of winning, and q = 1 − p is the probability of losing. The formula maximises the expected logarithm of wealth, which is equivalent to maximising the long-run compound growth rate of your bankroll. Q: What is "fractional Kelly" and why use it? A: Full Kelly maximises growth in the long run but produces very large drawdowns because it assumes you know the true probability exactly. In practice, your probability estimate always has error. Betting a fraction — typically 25% to 50% of full Kelly — sacrifices a small amount of theoretical growth rate in exchange for dramatically smoother equity curves and reduced ruin risk. The log-growth curve is always steeper on the left (under-betting) than the right (over-betting), so the penalty for over-betting is much larger than for under-betting. Q: What does "edge" mean in the Kelly formula? A: Edge is the expected profit per unit staked: edge = b·p − q. A positive edge means the bet has a positive expected value — over many bets you expect to profit. A zero or negative edge means Kelly recommends betting 0% of your bankroll regardless of the odds. Q: How does the investment version of Kelly work? A: For continuous-return assets (stocks, funds), the Kelly fraction is f* = (μ − r) / σ², where μ is the expected annual return, r is the risk-free rate, and σ is the annual standard deviation of returns. This is closely related to the Sharpe ratio: f* = Sharpe / σ. In practice full investment Kelly is very aggressive (often 150–300% for equities), so practitioners routinely use 10–50% Kelly. Q: Can the Kelly Criterion lead to ruin? A: With exact probability knowledge, Kelly never reaches zero because you always bet a fraction of remaining bankroll (it is a multiplicative system). However, with uncertain probabilities — the typical real-world case — you can significantly over-bet. This is why fractional Kelly is standard. Over-betting beyond 2× Kelly produces worse long-run growth than not betting at all, a region sometimes called "overbetting into ruin territory." Q: How do I handle multiple simultaneous bets? A: For independent simultaneous bets, the approximate rule is to compute each bet's Kelly fraction independently using the full formula, then sum them. If the total exceeds your intended bankroll fraction, scale each bet proportionally downward, or apply a lower fractional Kelly across the board. The multi-bet table in this calculator does this automatically and highlights when total allocation exceeds 100%. #### Combinations with Repetition Calculator URL: https://geratools.com/combinations-with-repetition-calculator Free combinations-with-repetition calculator. Enter n (types) and r (choices) to get C(n+r-1, r) instantly — exact BigInt arithmetic, full working, factorial breakdown, and a side-by-side comparison with standard combinations. Runs entirely in your browser. How to use: 1. Enter n — the number of distinct item types: Type the count of different types available. For example, if you have 5 ice-cream flavours, enter 5. n must be at least 1. 2. Enter r — how many items you want to choose: Type the size of your selection. Repetition is allowed, so you can pick the same type more than once. r can be 0 (empty selection) or any positive integer. 3. Read the answer: The calculator immediately shows C(n+r-1, r), the full step-by-step working, the factorial values, and a comparison with standard combinations C(n, r). FAQ: Q: What is the formula for combinations with repetition? A: The formula is C(n+r-1, r) = (n+r-1)! / (r! × (n-1)!), also written as the multiset coefficient ⟨n r⟩. Here n is the number of distinct types and r is how many you are choosing. The derivation comes from the stars-and-bars argument: placing r identical balls into n labelled bins is equivalent to arranging r stars and (n-1) bars in a row of n+r-1 symbols. Q: How is combinations with repetition different from standard C(n, r)? A: Standard combinations C(n, r) count ways to pick r distinct items from n when no item can be repeated and order does not matter. Combinations with repetition allow the same type to be chosen multiple times, so the effective pool grows to n+r-1 positions. The result C(n+r-1, r) is always greater than or equal to C(n, r) for the same n and r. Q: What does stars and bars mean? A: Stars and bars is a visual proof technique. Imagine r identical stars (the items you pick) and n-1 vertical bars (the dividers between the n types). Any arrangement of these r+n-1 symbols uniquely defines a multiset selection — the count of stars between consecutive bars tells you how many of each type you chose. The number of arrangements is C(n+r-1, r). Q: Can r be larger than n in this formula? A: Yes — that is precisely the point of allowing repetition. You can pick r = 10 items from only n = 3 types because each type can appear multiple times. In contrast, standard combinations require r ≤ n. With repetition, C(3+10-1, 10) = C(12, 10) = 66. Q: When is the answer equal to 1? A: The answer is 1 in two cases: when r = 0 (the only selection is the empty selection, regardless of n) and when n = 1 (only one type exists, so every selection of any size must consist entirely of that type — exactly one way). Q: What are real-world uses of combinations with repetition? A: Common applications include counting flavour combinations at an ice-cream counter, the number of ways to distribute identical objects among labelled bins, generating multisets in probability problems, counting monomials of a given degree in polynomial algebra, and enumerating solutions to non-negative integer equations x1 + x2 + ... + xn = r. #### Z-Score to Percentile Calculator URL: https://geratools.com/z-score-to-percentile-calculator Free z-score to percentile calculator. Enter a z-score and get the cumulative probability, percentile rank, one-tail and two-tail p-values instantly. Or flip it: enter a percentile and get the exact z-score (probit). Includes a live bell-curve chart and common critical-value table. 100% client-side. How to use: 1. Choose a direction: Select "Z-score → Percentile" to find what proportion of a normal distribution lies below your value, or "Percentile → Z-score" to find the critical value that cuts off a given tail. 2. Enter your value: Type the z-score (any real number, e.g. 1.96) or the percentile (a number strictly between 0 and 100, e.g. 97.5). 3. Read the results: The primary result appears immediately. In z→percentile mode you also see the left-tail area, right-tail area, two-tail p-value, and the symmetric ±z coverage. A live bell-curve chart shades the area for you. 4. Use the critical-value table: Expand "Common critical values" to see the most important z-scores used in hypothesis testing, from z = −3.29 (0.05% tail) to z = +3.29 (99.95%), with the corresponding two-tail significance levels. FAQ: Q: What is a z-score and how does it relate to a percentile? A: A z-score measures how many standard deviations a value sits above or below the mean of a standard normal distribution (μ = 0, σ = 1). The percentile is the cumulative probability Φ(z) — the fraction of the distribution that lies at or below that z-score. For example, z = 1.6449 corresponds to the 95th percentile: exactly 95% of observations in a normal distribution fall below that point. Q: What is the formula for converting a z-score to a percentile? A: The percentile is Φ(z) = (1/2)[1 + erf(z / √2)], where erf is the Gauss error function. Because erf has no closed form, this calculator uses the Horner-form rational approximation from Abramowitz & Stegun §26.2.17, which achieves a maximum absolute error below 7.5 × 10⁻⁸ — well beyond what any practical application requires. Q: How do I find the z-score for a given percentile (the inverse problem)? A: Switch to "Percentile → Z-score" mode and enter the desired percentile. The calculator applies the Beasley–Springer–Moro probit algorithm, which inverts the normal CDF to 5 × 10⁻⁸ accuracy. For example, entering 97.5 returns z ≈ 1.9600 — the familiar 5% two-tail critical value used in hypothesis testing. Q: What is the difference between a one-tail and a two-tail p-value? A: A one-tail (left-tail) p-value is simply Φ(z) — the area to the left of your z-score. The right-tail p-value is 1 − Φ(z). The two-tail p-value is 2 × min(Φ(z), 1 − Φ(z)), which measures how extreme the result is without specifying a direction. In hypothesis testing, z = 1.96 gives a two-tail p-value of exactly 0.05 (5%). Q: Why does the 68-95-99.7 rule come from z-scores? A: The rule states that roughly 68% of a normal distribution lies within ±1σ of the mean (z between −1 and +1), 95% within ±2σ (z ≈ ±1.96), and 99.7% within ±3σ. These are just the "between −|z| and +|z|" values from the CDF: Φ(1) − Φ(−1) ≈ 0.6827; Φ(1.96) − Φ(−1.96) ≈ 0.9500; Φ(3) − Φ(−3) ≈ 0.9973. The calculator reports this symmetric coverage in the secondary stats. Q: Can I use this for non-standard normal distributions? A: Yes — with a small extra step. If your data has mean μ and standard deviation σ, first convert your raw value x to a z-score using z = (x − μ) / σ, then enter that z-score here. The percentile result is the same because any normal distribution is just a rescaled standard normal. The companion z-score calculator on this site can do the standardisation for you. ### Geometry #### CO2 Cylinder Duration Calculator URL: https://geratools.com/aquarium-co2-cylinder-duration Enter your CO2 cylinder size and either a bubble-per-second injection rate or a daily grams figure to estimate how many days of CO2 remain. For planted-aquarium hobbyists planning refills. How to use: 1. Enter cylinder size: Type your CO2 cylinder's net gas capacity in grams. Common sizes are 95 g (paintball-style), 500 g, 1000 g, and 2000 g. 2. Set your injection rate: Choose to enter either bubbles per second (with a daily on-time) or a known grams-per-day figure. 3. Read the days remaining: The tool converts your rate to grams per day and divides the remaining cylinder weight by it to estimate days until refill. FAQ: Q: How much CO2 is in one bubble? A: A standard aquarium bubble counter bubble is roughly 0.0001 g of CO2 (about 0.05 mL at the gas density of CO2). This tool uses that conversion, so 1 bubble per second is about 8.6 g per day if the system runs continuously. Q: Should I run CO2 24 hours a day? A: Most planted-tank keepers run CO2 only during the photoperiod, typically 8 to 10 hours, switching it off at night when plants do not photosynthesise. Set the daily on-hours field to match your timer for an accurate estimate. Q: Why is my real-world duration different? A: Bubble size varies between diffusers and counters, solenoid ramp-up wastes a little gas, and regulators leave residual pressure that cannot be used. Treat the estimate as a planning figure and order a refill before the cylinder runs fully dry. Q: What size cylinder should I buy? A: Match cylinder size to how often you want to refill. A small 95 g cartridge may last a nano tank weeks but a large display tank at high injection empties it in days, so larger tanks usually justify a refillable 1 to 2 kg bottle. Q: How do I find grams per day directly? A: Weigh the cylinder on a kitchen scale a week apart; the difference divided by the days is your real grams-per-day. Enter that in the grams mode for the most accurate duration, since it captures your exact diffuser efficiency. #### Lightning Protection Rolling Sphere Calculator URL: https://geratools.com/lightning-protection-rolling-sphere Apply the rolling sphere method to find the zone of protection for an air terminal. Choose the NFPA 780 ordinary sphere (150 ft / 46 m) or an IEC 62305 protection level, then compute single-terminal protective radius and sphere sag between two terminals. How to use: 1. Pick the sphere radius: Choose the NFPA 780 ordinary sphere or an IEC 62305 protection level; the radius sets how deeply the sphere can dip between terminals. 2. Enter terminal geometry: Provide the air terminal height above the roof and, for a pair of terminals, the horizontal spacing between them. 3. Read the protected zone: The tool returns the single-terminal protective radius and the sphere sag at the midpoint, flagging whether an object there is protected or exposed. FAQ: Q: What is the rolling sphere method? A: It is a geometric design method where an imaginary sphere of a fixed radius is rolled over a structure and its air terminals. Any surface the sphere can touch is exposed to a direct strike, while areas in the sphere's shadow are protected. Q: What sphere radius does NFPA 780 use? A: NFPA 780 commonly uses a 150 ft (about 46 m) rolling sphere for ordinary structures. IEC 62305 uses smaller spheres for higher protection levels: 20 m for Level I, 30 m for Level II, 45 m for Level III and 60 m for Level IV. Q: How is the protective radius of one terminal found? A: From rolling-sphere geometry, the protective radius on the surface equals the square root of (2 times R times h minus h squared), where R is the sphere radius and h the terminal height. The sphere rests on the tip and the roof, touching the roof at that distance. Q: Why does spacing between terminals matter? A: Between two terminals the sphere sags downward by R minus the square root of (R squared minus half-the-spacing squared). If that sag drops below the height of an object at the midpoint, the object is exposed and you must add a terminal or reduce the spacing. Q: Does a smaller sphere give more protection? A: Yes. A smaller radius sphere dips less and touches fewer points, so it demands more, closely spaced air terminals and yields a higher protection level. Larger spheres are permitted for ordinary structures with a lower required protection level. #### Shell Thickness & Perimeter Calculator URL: https://geratools.com/multiwall-shell-thickness Computes total outer shell thickness for an FDM 3D print from the number of perimeter walls and the nozzle diameter or line width. Flags whether the shell meets a structural minimum and suggests the perimeter count needed. How to use: 1. Enter perimeters and nozzle: Type how many perimeter walls (shells) the slicer will print and your nozzle diameter in millimetres. 2. Optionally override line width: If your line width differs from the nozzle diameter, tick the override and enter it. Many profiles use 100–120% of nozzle diameter. 3. Read the shell thickness: The tool multiplies perimeters by line width to give total wall thickness and tells you whether it meets the structural minimum, suggesting more perimeters if needed. FAQ: Q: How is shell thickness calculated? A: Total shell thickness equals the number of perimeters multiplied by the line width: thickness = perimeters × line width. For example, 3 perimeters at a 0.4 mm line width gives 1.2 mm of solid wall. The line width defaults to the nozzle diameter unless you override it. Q: Is line width the same as nozzle diameter? A: By default most slicers set the extrusion line width equal to the nozzle diameter, but you can change it. Common settings run from about 100% to 120% of the nozzle diameter; a wider line lays down more plastic per pass for stronger walls and faster prints, while a narrower line captures finer detail. Q: How many perimeters should I use? A: Two to three perimeters suit most parts; three or more for anything structural. With a 0.4 mm nozzle, three perimeters give about 1.2 mm of wall, which is strong for most uses. Adding perimeters strengthens a part far more efficiently than raising infill density, because the outer shell carries most of the load. Q: Why does shell thickness matter more than infill? A: In bending and impact, stress concentrates at the outer surface, so the perimeters do most of the structural work. A part with thick walls and modest infill is usually stronger and lighter than one with thin walls and dense infill. Increasing perimeters is the most weight-efficient way to add strength. Q: What is the minimum wall thickness I can print? A: The thinnest printable wall is roughly one line width — about the nozzle diameter — but single-wall parts are fragile. For durable parts aim for at least two perimeters (around 0.8 mm on a 0.4 mm nozzle). The calculator flags shells below about 0.8 mm and suggests how many perimeters reach that minimum. #### Circle of Fifths Key Relationship Tool URL: https://geratools.com/music-key-circle-of-fifths Interactive circle of fifths that identifies the relative minor, parallel minor, subdominant, dominant, and secondary dominant for any key. Suggests common borrowed chords and modulation pivot points for songwriting and music theory study. How to use: 1. Pick a key: Select any major or minor key from the dropdown. The tool reads the key's position on the circle of fifths. 2. Read the related keys: The relative, parallel, subdominant, dominant, and secondary-dominant keys appear instantly with their key signatures. 3. Use the modulation hints: Borrowed chords and pivot-chord suggestions show easy routes to move from your key to a neighbouring one. FAQ: Q: What is the circle of fifths? A: It is a diagram arranging the 12 pitch classes in a ring, each a perfect fifth (7 semitones) apart clockwise. Moving clockwise adds one sharp to the key signature; moving anticlockwise adds one flat. It makes key relationships and chord function visible at a glance. Q: How do I find the relative minor of a key? A: The relative minor sits a minor third (3 semitones) below the major tonic and shares the same key signature. For C major the relative minor is A minor. On the circle, the relative minor of any major key occupies the same slot on the inner ring. Q: What is the difference between relative and parallel keys? A: A relative key shares the same notes but has a different tonic (C major and A minor). A parallel key shares the same tonic but a different mode (C major and C minor). Parallel keys differ by three accidentals and are the source of most borrowed chords. Q: What are borrowed chords? A: Borrowed chords are taken from the parallel mode. In a major key the most common borrowings are the minor iv, bVI, bVII, and bIII from the parallel minor. They add colour and a sense of mode mixture without leaving the home key. Q: How do pivot chords help with modulation? A: A pivot chord is a chord shared by both the current key and the target key. You reinterpret its function (for example IV in C becomes I in F) and then cadence in the new key. The subdominant and dominant neighbours on the circle share the most common chords, making them the smoothest modulations. #### Refrigerant Recovery Cylinder Capacity Calculator URL: https://geratools.com/refrigerant-recovery-cylinder-calculator Enter cylinder tare weight, current scale weight, rated capacity, and a system charge to compute net refrigerant, current fill percentage, and remaining capacity, flagging the 80% gross fill limit under DOT 49 CFR 173.301. For HVAC and EPA 608 technicians. How to use: 1. Weigh and enter the cylinder: Place the recovery cylinder on a calibrated scale and enter its stamped tare weight and the current weight reading. 2. Enter rated capacity and charge: Type the cylinder's rated refrigerant capacity at the 80 percent limit and the weight of the system charge you intend to recover. 3. Read the result: The tool shows the net refrigerant present, the current fill percentage, the remaining capacity, and whether the new charge fits under the 80 percent limit. FAQ: Q: Why is the fill limit 80 percent? A: Liquid refrigerant expands as it warms. DOT 49 CFR 173.301 requires that a refrigerant cylinder hold no more than 80 percent of its water capacity by weight at 70 degrees Fahrenheit, leaving a vapour cushion so the cylinder does not go hydrostatically solid and rupture on a hot day. Q: How do I find the net refrigerant already in the cylinder? A: Subtract the stamped tare weight, marked TW on the cylinder, from the current reading on your scale. The difference is the weight of refrigerant present. Always use a calibrated refrigerant scale rather than estimating from pressure. Q: What is the rated refrigerant capacity I should enter? A: Enter the maximum refrigerant the cylinder may legally hold, which is the 80 percent number. Many recovery cylinders are sold by this figure, for example a 50 pound tank that is rated to hold about 47 pounds of R-410A. Check the cylinder label or the manufacturer's data. Q: What happens if the charge will not fit? A: The tool warns you and you must use a second cylinder. Forcing more refrigerant into a tank already near 80 percent is both unsafe and a violation. Recovery into an overfilled cylinder can cause it to become liquid-full and burst. Q: Does the refrigerant type change the result? A: The 80 percent weight rule applies to all refrigerants, but each one has a different density, so a given cylinder holds a different weight of R-22 than of R-410A. Always match the cylinder's labeled rated capacity to the refrigerant you are recovering and never mix refrigerants in one cylinder. #### Pythagorean Theorem Calculator URL: https://geratools.com/pythagorean-theorem-calculator Free Pythagorean theorem calculator — find the hypotenuse from two legs, or a missing leg from the hypotenuse and the other leg. It runs entirely in your browser and nothing is uploaded. How to use: 1. Choose what to solve for: Pick whether you want the hypotenuse (from both legs) or a missing leg (from one leg and the hypotenuse). 2. Enter the known sides: Type the two known side lengths into the fields. 3. Read the answer: The missing side is shown instantly, along with the formula used. FAQ: Q: What does this calculator solve? A: The Pythagorean theorem, a² + b² = c². It finds the hypotenuse c from two legs, or a missing leg from the hypotenuse and the other leg. Q: Why does it say the hypotenuse must be longer than the leg? A: In a right triangle the hypotenuse is always the longest side, so solving for a leg requires the hypotenuse to be greater than the known leg — otherwise no real triangle exists. Q: How do I find the hypotenuse from two legs? A: Square each leg, add them, and take the square root: c = √(a² + b²). For legs of 3 and 4, c = √(9 + 16) = √25 = 5. Q: How do I find a missing leg? A: Rearrange to b = √(c² − a²). With a hypotenuse of 5 and a leg of 3, the other leg is √(25 − 9) = √16 = 4. Q: What is a Pythagorean triple? A: A Pythagorean triple is a set of three whole numbers that satisfy a² + b² = c², such as 3-4-5, 5-12-13 and 8-15-17. These make exact right triangles with integer sides. Q: Does the theorem only work for right triangles? A: Yes. a² + b² = c² holds only for right-angled triangles, where c is the side opposite the 90° angle. For other triangles you need the law of cosines instead. Q: Is anything uploaded? A: No — every calculation runs entirely in your browser and nothing is sent anywhere. #### Body Surface Area Calculator URL: https://geratools.com/body-surface-area Free body surface area (BSA) calculator using the Du Bois, Mosteller and Haycock formulas. Enter height and weight in metric or imperial to scale doses and clinical values. Runs entirely in your browser. How to use: 1. Pick your units: Choose metric (cm / kg) or imperial (ft·in / lb). 2. Enter height and weight: Type your measurements and the BSA updates instantly. 3. Choose a formula: Switch between Du Bois, Mosteller and Haycock. FAQ: Q: Which BSA formula should I use? A: Du Bois & Du Bois (1916) is the historical standard. Mosteller (1987) is the simplest and most widely used clinically. Haycock (1978) works well across children and adults. This tool lets you switch between all three. Q: What is the Mosteller formula? A: BSA (m²) = √(height in cm × weight in kg ÷ 3600). It is popular because it is easy to compute by hand and agrees closely with the older Du Bois formula. Q: What is body surface area used for? A: BSA scales many clinical values to body size — most commonly chemotherapy and other drug doses, cardiac index, and burn assessment. It often tracks physiology better than weight alone. Q: Why do the three formulas give slightly different results? A: Each was fitted to different reference data with different exponents, so they diverge a little, especially at the extremes of height and weight. The differences are usually small for typical adults. Q: Does it work in imperial units? A: Yes. Feet, inches and pounds are converted to centimetres and kilograms before the formulas are applied, so the BSA is always returned in square metres. Q: Is this a substitute for clinical judgement? A: No. It is a calculation aid. Dosing and clinical decisions must be made by a qualified professional using the appropriate reference for the patient. Q: Is my data sent anywhere? A: No. Every calculation runs locally in your browser and nothing is uploaded. #### Hexagon Calculator URL: https://geratools.com/hexagon-calculator Free regular hexagon calculator — enter the side, a diagonal or the area and get every other property including perimeter, long and short diagonals and apothem. Runs entirely in your browser. How to use: 1. Choose what you know: Pick whether you know the side length, a diagonal, or the area. 2. Enter the value: Type the measurement and the tool derives the side length. 3. Read every property: Area, perimeter, both diagonals and the apothem appear instantly. FAQ: Q: How do you find the area of a regular hexagon? A: Area = (3 x square root of 3 / 2) x side squared, which is about 2.598 x side squared. A regular hexagon is made of six equilateral triangles, which is where this formula comes from. Q: What is the difference between the long and short diagonal? A: The long diagonal runs vertex to vertex and equals twice the side length. The short diagonal runs across the flats and equals the side length times the square root of 3 (about 1.732 x side). Q: What is the apothem of a hexagon? A: The apothem is the distance from the centre to the middle of a side (the inradius). For a regular hexagon it equals (square root of 3 / 2) x side, about 0.866 x side. It is half the short diagonal. Q: Can I work backwards from the area or a diagonal? A: Yes. Choose what you know — side, long diagonal, short diagonal, or area — and the tool first solves for the side, then derives every other property from it. Q: What is the "width across flats" of a hexagon? A: That is the short diagonal: the distance between two opposite flat sides, equal to side x square root of 3. It is the measurement that matters for fitting a hex nut or bolt to a spanner. Q: Does this tool upload anything? A: No — all maths happens in your browser and no data is sent anywhere. #### Ramp Slope Calculator URL: https://geratools.com/ramp-slope-calculator Free ramp slope calculator: enter any two of rise, run, ramp length, angle or percent grade to get every representation plus ADA §405.2 and BS 8300 compliance checks. 100% browser-based, nothing uploaded. How to use: 1. Choose what you already know: Pick a solve mode from the dropdown — Rise + Run is the most common. Switch to Imperial (ft) if your measurements are in feet. 2. Enter your two measurements: Type in the values, for example a 0.5 m rise over a 6 m horizontal run. Results update instantly. 3. Read the compliance badges: The green or red badges tell you at a glance whether the ramp meets ADA §405.2 (1 in 12 maximum) and UK BS 8300 preferred gradient (1 in 20). 4. Check the correction hint: If the slope fails ADA, the calculator shows exactly what rise or run would bring it into compliance. 5. Copy or expand all representations: Hit Copy results to paste into a spec sheet, or open All representations for per-mille, mm/m, in/ft and full decimal values. FAQ: Q: What is the maximum slope for an ADA-compliant ramp? A: ADA Standards for Accessible Design §405.2 sets the maximum running slope at 1:12, which is 8.33 %. This means for every 1 unit of rise there must be at least 12 units of horizontal run. Cross-slope (side-to-side) is limited to 1:48 (2.08 %) separately. Q: How do I calculate ramp slope from rise and run? A: Slope % = (rise ÷ run) × 100. For example, a 0.5 m rise over 6 m of run gives (0.5 ÷ 6) × 100 = 8.33 %, exactly 1:12. The angle is arctan(rise ÷ run), and the slant length (hypotenuse) is √(rise² + run²). Q: What gradient does UK BS 8300 recommend for wheelchair ramps? A: BS 8300:2018 recommends a preferred gradient of 1:20 (5 %) for new ramp construction where space allows. The absolute maximum for a short ramp serving wheelchair users is 1:12 (8.33 %) for a maximum rise of 500 mm. Steeper slopes increase rolling resistance significantly and can be hazardous for unassisted electric wheelchair users. Q: What is the difference between slope percent and slope ratio? A: Slope percent is (rise ÷ run) × 100, so a 1:20 ramp is 5 %. Slope ratio 1:n means 1 unit of rise per n units of run. Per-mille (‰) is simply slope% × 10, commonly used in rail and road engineering. This calculator shows all three, plus the angle in degrees. Q: How long does a ramp need to be for a given rise? A: For ADA compliance, minimum run = rise × 12. A 300 mm (0.3 m) step therefore needs at least 3.6 m of horizontal run, giving a ramp length (hypotenuse) of √(0.3² + 3.6²) ≈ 3.61 m. Use the Rise + Run mode, set rise to 0.3 and run to 3.6 to verify. Q: Can I use feet and inches instead of metres? A: Yes. Switch the Unit system to Imperial to work in feet. If your measurement is in inches, divide by 12 first — for example 6 inches of rise = 0.5 ft. The calculator keeps all computations in the unit you choose and labels results accordingly. #### Rise Over Run Calculator URL: https://geratools.com/rise-over-run-calculator Free rise over run calculator: enter rise and run to get slope, angle of inclination, percentage grade, 1:n ratio and roof pitch. Or solve for the missing rise or run. Visual diagram, unit converter (m/ft/in/cm). 100% browser-based — nothing uploaded. How to use: 1. Choose what to solve for: Pick Slope (rise divided by run), Rise (slope times run), or Run (rise divided by slope) from the Solve for menu. 2. Select your units: Choose metres, feet, inches or centimetres depending on your project. The unit applies to both rise and run inputs. 3. Enter the known values: Type the rise and run lengths (or the slope decimal if solving for rise or run). Results update instantly. 4. Read the outputs: The calculator shows slope, angle of inclination, percentage grade, the 1-to-n ratio, hypotenuse distance and roof pitch in X-in-12 notation. 5. Convert units if needed: Expand the Unit Converter panel at the bottom to convert any measurement between metres, feet, inches and centimetres. FAQ: Q: What is rise over run? A: Rise over run is the standard definition of slope. Rise is the vertical change (height gained or lost) and run is the horizontal distance covered. Dividing rise by run gives the slope — for example a rise of 3 metres over a run of 12 metres is a slope of 0.25, or 25%. Q: How do I convert slope to an angle? A: Use the inverse tangent: angle = arctan(rise / run). A slope of 0.25 gives arctan(0.25) = 14.04°. A slope of 1 (45°) means the incline rises by exactly one unit for every unit of horizontal distance. Q: What is percentage grade? A: Percentage grade is slope expressed as a percentage — simply slope multiplied by 100. A slope of 0.05 is a 5% grade. Road engineers use this notation; a steep mountain road might be 10–12% grade. Q: What does a 1-in-12 roof pitch mean? A: A 1-in-12 pitch means the roof rises 1 unit for every 12 units of horizontal run — roughly a slope of 0.0833 or about 4.76°. Steeper roofs like 6-in-12 (26.57°) shed snow better; shallow pitches suit warm climates. Q: How do I calculate the rise needed for a wheelchair ramp? A: UK and international accessibility standards recommend a maximum slope of 1:12 (slope = 0.0833). If the doorstep is 0.15 m above pavement level, the run needed is rise ÷ slope = 0.15 ÷ 0.0833 = 1.8 m. Enter rise = 0.15 and slope = 0.0833 in Run mode to confirm. Q: What is the hypotenuse shown in the results? A: The hypotenuse is the actual distance along the slope — the length of the inclined surface itself, calculated from Pythagoras as sqrt(rise² + run²). This is the length of timber or ramp material you need, not just the horizontal footprint. Q: Is any data sent to a server? A: No. Every calculation runs entirely inside your browser using JavaScript. No numbers, dimensions or project details are ever uploaded anywhere. #### Right Triangle Calculator URL: https://geratools.com/right-triangle-calculator Free right triangle calculator. Enter any two values (legs, hypotenuse, or angle) to instantly find all sides, angles, area, perimeter and trig ratios. Shows full step-by-step working. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose what you know: Pick the two values you already have from the drop-down — both legs, one leg and the hypotenuse, one leg and an angle, or the hypotenuse and an angle. 2. Enter your numbers: Type the side lengths (in any consistent unit — cm, m, inches, etc.) or the angle in decimal degrees. The diagram updates live. 3. Read all results at once: The calculator fills in all three sides, both acute angles, area, and perimeter in the results table below the diagram. 4. Check the step-by-step working: Scroll to "Step-by-step working" to see every formula applied with your numbers substituted in. Copy the full working with one click. 5. Verify trig ratios: The trig ratio table at the bottom shows sin, cos and tan for both acute angles — useful for checking your own working or preparing for an exam. FAQ: Q: What is a right triangle? A: A right triangle (or right-angled triangle) is a triangle in which one interior angle is exactly 90 degrees. The side opposite the right angle is the longest side and is called the hypotenuse. The other two sides are called legs (or catheti). Because the three angles must sum to 180 degrees, the two acute angles always add up to exactly 90 degrees. Q: How does the calculator find the hypotenuse? A: It uses the Pythagorean theorem: c = sqrt(a^2 + b^2), where a and b are the two legs. For example, legs 3 and 4 give c = sqrt(9 + 16) = sqrt(25) = 5. This is the classic 3-4-5 right triangle, the simplest integer-sided example. Q: How are the angles found from two side lengths? A: If both legs are known, angle A is found with the inverse tangent (arctan) of a divided by b. If one leg and the hypotenuse are known, the inverse sine (arcsin) of the leg divided by the hypotenuse gives the opposite angle. The second acute angle is then simply 90 degrees minus the first, because the two acute angles are complementary. Q: What is SOH CAH TOA? A: SOH CAH TOA is a memory aid for the three basic trig ratios in a right triangle. SOH means sin = Opposite over Hypotenuse. CAH means cos = Adjacent over Hypotenuse. TOA means tan = Opposite over Adjacent. This calculator applies all six ratios (sin, cos, tan for each acute angle) and shows them in the trig ratio table. Q: Can I use this for non-right triangles? A: No. This tool is designed specifically for right triangles. For a general triangle where no angle is known to be 90 degrees, use a general triangle calculator that applies the Law of Sines and Law of Cosines. However, any triangle can be split into two right triangles by dropping a perpendicular from one vertex to the opposite side. Q: What units does the calculator use? A: The calculator is unit-agnostic. Enter lengths in any unit (millimetres, centimetres, metres, inches, feet) and all results are in the same unit. Angles are always in decimal degrees. Area is in the square of your length unit and perimeter is in the same length unit. #### Heron's Formula Calculator URL: https://geratools.com/heron-formula-calculator Free Heron's Formula calculator. Enter three side lengths and instantly get the triangle area, perimeter, interior angles, altitudes, inradius, and circumradius — with step-by-step working shown. Runs entirely in your browser. How to use: 1. Enter side a: Type the length of the first side in any unit (cm, m, inches, feet — the result will be in the same unit squared). 2. Enter side b: Type the length of the second side. 3. Enter side c: Type the length of the third side. The calculator checks the triangle inequality automatically and shows an error if the sides cannot form a real triangle. 4. Read the results: Area, perimeter, semi-perimeter, interior angles, altitudes, inradius, and circumradius appear immediately along with a labelled SVG diagram and the full four-step working. 5. Copy results: Click the Copy results button to paste the complete output — including working steps — into any document or spreadsheet. FAQ: Q: What is Heron's formula? A: Heron's formula computes the area of a triangle directly from its three side lengths (a, b, c) without needing any angle. First, calculate the semi-perimeter: s = (a + b + c) / 2. Then: Area = sqrt(s(s-a)(s-b)(s-c)). The formula is named after the ancient Greek mathematician Hero of Alexandria (c. 10–70 AD), who proved it in his work Metrica. Q: Why use Heron's formula instead of the base-times-height formula? A: The base-times-height formula (Area = 0.5 x base x height) requires you to know the altitude, which you often don't if only the side lengths are given. Heron's formula works purely from the three side lengths — ideal for surveying, construction, and any situation where you measure distances rather than heights. Q: What is the semi-perimeter and why does the formula use it? A: The semi-perimeter s = (a + b + c) / 2 is simply half the perimeter. Heron's formula can be written without it (Area = 0.25 x sqrt((a+b+c)(-a+b+c)(a-b+c)(a+b-c))), but the s notation compresses the four factors into a tidier form and makes it easier to compute by hand. Q: What is the triangle inequality and when does a triangle not exist? A: A valid triangle requires that each side be strictly shorter than the sum of the other two: a + b > c, a + c > b, and b + c > a. If any of these conditions fails, the three lengths are collinear or degenerate and no real triangle exists. Heron's formula would yield a negative number under the square root in that case, which is why the calculator flags it as an error. Q: What are the inradius and circumradius? A: The inradius (r) is the radius of the largest circle that fits inside the triangle, tangent to all three sides. It equals Area / s, where s is the semi-perimeter. The circumradius (R) is the radius of the circle passing through all three vertices (circumscribed circle). It equals (a x b x c) / (4 x Area). Both are useful in trigonometry, geometry proofs, and engineering design. Q: Is the calculator accurate for very small or very large side lengths? A: Yes for most practical inputs. The calculation uses IEEE 754 double-precision floating-point arithmetic (about 15-16 significant digits). For extremely large or extremely small values (for example sides around 1e154 or 1e-154), floating-point rounding may introduce small errors. Results are rounded to 6 significant figures for display. ### Math & Algebra #### ACT Score Percentile Calculator URL: https://geratools.com/act-score-percentile-calculator Enter your ACT composite score from 1 to 36 to see your national percentile rank, based on ACT Inc.'s published score distributions for recent graduating classes. How to use: 1. Enter your ACT composite: Type your composite score between 1 and 36. 2. View your percentile: The tool returns your national percentile rank from ACT's published distribution. 3. Interpret your standing: Read the summary to see roughly what fraction of test takers you scored above. FAQ: Q: What is an ACT percentile? A: It is the percentage of recent ACT test takers who scored at or below your composite. A 90th percentile composite means you did better than about 90 percent of students. It reflects relative standing rather than the number of questions answered correctly. Q: Which distribution does this use? A: It uses ACT Inc.'s national rank tables for recent graduating classes, which report the cumulative percent of students at or below each composite score. These are the figures printed on ACT score reports. Q: What is a good ACT composite? A: The national average composite is around 19 to 21. A score of 24 sits near the 74th percentile, 30 near the 93rd, and 33 or above places you in roughly the top 2 percent, the range typical of highly selective colleges. Q: Why do percentiles change near the top? A: Very few students score above 33, so each point at the top of the scale represents a large jump in rarity. A 35 already sits above 99 percent of test takers, which is why the top percentiles compress. Q: Do percentiles change every year? A: Yes, slightly. ACT updates its national rank tables annually as new cohorts test, so a given composite can move a point or two in percentile across years. This tool uses recent published figures. #### Phenytoin Free Fraction Estimator in Renal Failure URL: https://geratools.com/adjusted-phenytoin-renal Apply the Winter-Tozer equation with a renal-failure adjustment to estimate the albumin-corrected phenytoin concentration when hypoalbuminaemia and low GFR coexist. Helps pharmacists dose epilepsy in CKD. Runs in your browser. How to use: 1. Enter the measured total phenytoin: Type the laboratory total phenytoin concentration in micrograms per millilitre. 2. Enter serum albumin: Provide the patient's serum albumin in grams per decilitre so the correction can account for reduced protein binding. 3. Flag renal impairment: Tick the box if creatinine clearance is below 10 to 25 mL per minute. The tool switches to the renal-failure binding factor and reports the corrected concentration. FAQ: Q: Why does phenytoin need a correction? A: Phenytoin is highly protein bound to albumin, but only the free, unbound fraction is pharmacologically active. When albumin is low the bound portion falls, so the same free level corresponds to a lower total level. A normal total can then mask a therapeutic or toxic free concentration. Q: What is the Winter-Tozer equation? A: It estimates the total phenytoin a patient would have at normal albumin. The standard form is measured total divided by the quantity 0.2 times albumin plus 0.1. The 0.2 reflects normal binding and the 0.1 is the residual free fraction, giving an albumin-normalised value to compare against the usual 10 to 20 range. Q: How does renal failure change it? A: Uraemia reduces phenytoin binding to albumin beyond what low albumin alone explains, so the binding coefficient drops from 0.2 to 0.1. The renal-adjusted equation is measured total divided by 0.1 times albumin plus 0.1, which yields a higher corrected value reflecting the greater free fraction. Q: What target range applies to the corrected value? A: The corrected concentration is interpreted against the usual total phenytoin target of about 10 to 20 micrograms per millilitre, since it represents what the total would be at normal albumin and binding. Free phenytoin itself targets roughly 1 to 2 micrograms per millilitre. Q: Is this a substitute for a free phenytoin assay? A: No. When available, a directly measured free phenytoin level is more reliable than any equation, especially in unstable or critically ill patients. The Winter-Tozer estimate is a practical tool when only total phenytoin and albumin are known. #### Tape Machine Operating Level Calculator URL: https://geratools.com/analog-tape-saturation-level Converts between nanowebers-per-metre (nWb/m) tape flux operating levels and dB relative to a chosen reference fluxivity such as 185, 250, 320 or 510 nWb/m. Used to set and compare analogue tape machine operating levels. How to use: 1. Choose your reference fluxivity: Pick the operating level your machine is calibrated to (the flux that equals 0 VU), such as 185 or 250 nWb/m, or type a custom value. 2. Pick a conversion direction: Convert a flux level in nWb/m to its dB value relative to the reference, or convert a dB offset back to a flux level. 3. Read the result: The tool shows the flux in nWb/m and its level in dB relative to your reference, so you can compare elevated levels and headroom. FAQ: Q: What is tape operating level in nWb/m? A: Operating level (fluxivity) is the magnetic flux recorded on the tape that corresponds to 0 VU on the meter, measured in nanowebers per metre (nWb/m). A higher fluxivity means a hotter recording with more headroom before saturation, but also a higher noise floor relative to the noise of the tape itself. Q: How do I convert nWb/m to dB? A: Use dB = 20 × log10(flux / reference). For example, 250 nWb/m relative to a 185 nWb/m reference is 20 × log10(250/185) ≈ +2.6 dB. To go the other way, flux = reference × 10^(dB/20). Q: What is the difference between 185 and 250 nWb/m? A: Both are common 0 VU reference fluxivities. 185 nWb/m is the traditional Ampex/NAB operating level; 250 nWb/m is a hotter 'elevated' level about +2.6 dB higher. Recording at the elevated level prints a stronger signal, improving signal-to-noise but reducing remaining headroom before saturation. Q: Why use a higher operating level? A: Modern tape formulations tolerate higher flux without excessive distortion, so studios elevate the operating level (e.g. to 320 or 355 nWb/m) to push the recorded signal further above the tape's hiss floor. The trade-off is less headroom and more risk of audible saturation on loud transients, which some engineers exploit deliberately for 'tape compression'. Q: Does this match my calibration tape? A: Calibration tapes are recorded at a stated fluxivity (often 185, 250 or 320 nWb/m). Play the tape and adjust playback gain so the reference tone reads exactly 0 VU; the deck is then aligned to that operating level, and every other level follows the dB = 20·log10(flux/reference) relationship shown here. #### Sine Bar / Sine Plate Setup Calculator URL: https://geratools.com/angle-plate-sine-bar-calculator Computes the precision gauge-block stack height H = L x sin(theta) for a sine bar of length L (5 in or 10 in) to set any angle, and back-calculates the angle from a measured stack height. Outputs the angle in degrees, minutes, and seconds for machinist and inspection setups. How to use: 1. Enter the sine bar length: Type the center distance of your sine bar or sine plate, typically 5 inches or 10 inches between the roll centers. 2. Enter angle or measured height: Switch to angle-to-height to enter the target angle, or height-to-angle to enter a measured gauge-block stack and read the angle. 3. Read the result: The tool returns the exact gauge-block stack height, or the angle in degrees, minutes, and seconds, for setting the sine bar precisely. FAQ: Q: What is the sine bar formula? A: The gauge-block stack height equals the sine bar length times the sine of the desired angle: H = L x sin(theta). For a 5-inch sine bar set to 30 degrees, the stack is 5 x 0.5 = 2.5000 inches. The roll-to-roll center distance is the length L. Q: Why is a sine bar so accurate? A: Because it converts an angle into a linear height that can be set with gauge blocks accurate to millionths of an inch. The sine relationship is most sensitive near 90 degrees and least sensitive near 0, so sine bars are most accurate for small to moderate angles. Q: Can I use any gauge-block combination? A: You stack blocks to reach the target height as closely as your set allows. The tool reports the exact required height so you can wring together blocks that sum to it. A standard 81-piece set reaches almost any height to 0.0001 inch. Q: How do I convert decimal degrees to minutes and seconds? A: Multiply the decimal part by 60 to get minutes, then multiply the leftover decimal by 60 for seconds. The tool does this automatically so you can match an angle stated in degrees-minutes-seconds on a drawing. Q: What is a sine plate? A: A sine plate is a wider sine bar with a hinged top surface for holding workpieces during grinding or inspection. The same formula applies: stack height equals the plate's hinge-to-roll length times the sine of the angle. Compound sine plates set two angles with two stacks. #### Water-to-Grain Ratio (Quarts per Pound) Calculator URL: https://geratools.com/beer-water-to-grain-ratio Calculate mash strike-water volume from your target thickness (1.0–1.5 qt/lb or 2.1–3.1 L/kg) and total grain weight. Shows the metric ratio, grain absorption, and how mash thickness affects enzyme activity for homebrewers. Runs 100% in your browser. How to use: 1. Enter your total grain bill: Add up every grain and adjunct in pounds, e.g. 10 lb for a standard 5-gallon batch. 2. Choose a mash thickness: Type your target ratio in quarts per pound — 1.25 qt/lb is a common all-purpose value. 3. Read the strike water volume: The calculator shows the water in quarts, gallons, and litres, plus grain absorption and the metric ratio. FAQ: Q: What is a good water-to-grain ratio? A: Most all-grain brewers use 1.0 to 1.5 quarts per pound (2.1 to 3.1 L/kg), with 1.25 qt/lb a popular all-rounder. Single-infusion mashes often sit around 1.25–1.5, while step mashes start thicker. Q: How does mash thickness affect the beer? A: Thinner mashes (above 1.5 qt/lb) favour beta-amylase, giving a more fermentable, drier wort. Thicker mashes (below 1.25 qt/lb) protect enzymes from heat denaturation and tend to produce more body and malt character. Q: How do I convert qt/lb to L/kg? A: Multiply quarts per pound by 2.0863 to get litres per kilogram. So 1.25 qt/lb equals about 2.61 L/kg. The calculator shows both automatically. Q: How much water does the grain absorb? A: Grain absorbs roughly 0.5 quarts (0.125 gallons) per pound, which stays behind in the mash tun. The calculator subtracts this so you can see how much wort you will actually collect before sparging. Q: Does this account for sparge water? A: No — this sizes only the strike (mash-in) water for your chosen thickness. Sparge water is calculated separately from your target pre-boil volume minus what you collect from the mash. #### Crop Water Use (ET) Estimator URL: https://geratools.com/crop-water-use-evapotranspiration-tool Estimates reference evapotranspiration with the Hargreaves temperature method, then multiplies by a crop coefficient (Kc) to give daily crop ET and scales it over a growth stage for seasonal water use. Subtracts effective rainfall to give a net irrigation requirement. An irrigation-scheduling aid for agronomists and irrigation managers. How to use: 1. Enter the weather: Type the daily maximum, minimum, and mean air temperature in Celsius, plus the extraterrestrial radiation for your latitude and date. 2. Pick the crop coefficient: Choose a crop and growth stage to load a typical Kc value, or enter your own Kc, and set the number of days in the stage. 3. Read crop ET and irrigation need: The tool computes reference ET, multiplies by Kc for daily crop ET, scales over the stage for seasonal use, and subtracts effective rainfall. FAQ: Q: What is the Hargreaves equation? A: The Hargreaves method estimates reference evapotranspiration as 0.0023 times extraterrestrial radiation times the square root of the daily temperature range times mean temperature plus 17.8. It needs only temperature data, making it useful where humidity, wind, and radiation are unavailable. Q: What is a crop coefficient (Kc)? A: Kc scales reference ET to a specific crop and growth stage. It is near 0.3 to 0.4 at emergence, rises to 1.05 to 1.2 at mid-season full canopy, then falls toward 0.5 to 0.9 at maturity. Multiplying reference ET by Kc gives the actual crop water use. Q: How do I find extraterrestrial radiation? A: Extraterrestrial radiation depends only on latitude and day of year and is tabulated in FAO Irrigation and Drainage Paper 56 in megajoules per square metre per day. The tool converts it internally so reference ET comes out in millimetres per day. Q: What is effective rainfall? A: Effective rainfall is the portion of rain that is actually stored in the root zone and used by the crop, after runoff and deep percolation losses. The net irrigation requirement is crop ET minus effective rainfall over the period. Q: Is Hargreaves as accurate as Penman-Monteith? A: Penman-Monteith is the FAO standard and is more accurate when full weather data is available. Hargreaves is a temperature-only approximation that performs well at monthly timescales and in data-sparse settings, but it can be biased in very humid or very windy locations. #### Pharmacy Dose Rounding Calculator URL: https://geratools.com/dose-rounding-calculator Takes a mathematically calculated dose and rounds it to the nearest practical tablet, capsule, or vial strength from your formulary list, with a percentage deviation check against a tolerance you set. For inpatient and community pharmacists. How to use: 1. Enter the calculated dose: Type the exact mathematically derived dose, for example the weight-based result from a dosing equation. 2. List your available strengths: Enter the tablet, capsule, or vial strengths your formulary stocks, separated by commas or spaces. 3. Read the rounded dose and deviation: The tool selects the nearest practical strength or whole multiple and shows how far it deviates from the target as a percentage. FAQ: Q: Why round a calculated dose at all? A: Calculated doses are rarely whole tablet or vial strengths. Rounding to a manufactured strength avoids splitting coated or modified-release products and makes the prescription practical to dispense and administer, provided the deviation stays within a clinically acceptable band. Q: How is the deviation percentage calculated? A: The tool computes (rounded dose minus target dose) divided by the target dose, times 100. A positive value means the rounded dose is higher than calculated and a negative value means it is lower. You set the tolerance that flags an acceptable result. Q: What is the difference between nearest strength and multiples mode? A: Nearest strength picks the single closest discrete strength from your list. Multiples mode snaps the dose to the nearest whole multiple of one chosen unit, which models taking several identical tablets such as two 25 mg tablets to reach 50 mg. Q: What tolerance should I use? A: Ten percent is a common default for many oral medicines, but narrow-therapeutic-index drugs such as some anticonvulsants or anticoagulants may need a tighter band. Always judge the acceptable deviation against the specific drug and patient. Q: Is this a substitute for clinical checking? A: No. It is an arithmetic aid that reproduces a rounding rule and a deviation check. A pharmacist must still confirm the rounded dose is safe and appropriate for the product, the indication, and the individual. #### Duration Humanizer URL: https://geratools.com/duration-humanizer Turn a raw duration in seconds into a clear, human-readable string like 2 hours, 34 minutes. Breaks the total into years, months, weeks, days, hours, minutes, and seconds with control over how many parts to show. Runs in your browser. How to use: 1. Enter the duration in seconds: Type or paste the total number of seconds you want to express in words. 2. Choose how many parts to show: Pick the maximum number of units, and optionally include weeks, to control how detailed the result is. 3. Read or copy the result: The humanized string updates instantly and the Copy button puts it on your clipboard. FAQ: Q: How long is a month in this tool? A: A month is treated as 30.4375 days, which is exactly one twelfth of a 365.25-day year. This average keeps long durations accurate without needing a specific calendar start date. Q: What does the maximum parts setting do? A: It limits how many units appear in the output. With a maximum of 2, a value of 90,061 seconds shows as 1 day, 1 hour rather than spelling out the remaining minutes and seconds, giving a rounded summary. Q: Does it handle negative numbers? A: Yes. A negative duration is humanized the same way and prefixed with a minus sign, which is useful for showing how far in the past an event was. Q: Why are weeks optional? A: Some people prefer days to roll straight from months, while others find weeks more intuitive. Toggling weeks on inserts a 7-day unit between days and months so you can match your own convention. Q: What happens with a value of zero? A: Zero seconds is shown as 0 seconds. Any leftover fraction of a second is dropped because the tool works in whole seconds. #### ELISA Standard Curve & Sample Concentration Calculator URL: https://geratools.com/elisa-standard-curve-calculator Fit a 4-parameter logistic standard curve to ELISA OD450 readings and interpolate unknown sample concentrations with dilution correction. Reports the a, b, c, d parameters and R-squared. Built for immunology and clinical diagnostics labs. Runs in your browser. How to use: 1. Paste your standards: Enter each standard as concentration then OD450 on its own line, including the blank or zero standard. 2. Enter the unknown reading: Type the OD450 of your sample and the dilution factor you used when running it on the plate. 3. Read the concentration: The tool fits a 4PL curve to the standards and inverts it to interpolate the sample concentration, then multiplies by the dilution. FAQ: Q: Why fit a 4PL curve instead of a straight line? A: ELISA dose-response data is sigmoidal: it plateaus at both very low and very high concentrations. A 4-parameter logistic curve captures both plateaus and the linear middle region, so it fits the full range far better than a straight line and gives accurate results near the curve ends. Q: What do the four parameters mean? A: Parameter a is the lower asymptote (response at zero analyte), d is the upper asymptote at saturation, c is the inflection point or EC50, and b is the Hill slope describing steepness. Together they define the whole sigmoid in the equation y equals d plus a minus d over 1 plus x over c to the power b. Q: Why is my sample reported as out of range? A: Interpolation only works between the curve asymptotes. If an unknown OD sits above your top standard or below your blank, the math cannot invert it reliably. Re-run that sample at a lower dilution to bring its reading inside the standard range. Q: What R-squared should I expect? A: A clean ELISA standard curve usually fits with R-squared above 0.98. A lower value points to an outlier standard, pipetting error, or a curve that has not reached both plateaus. Inspect the standards and consider dropping or repeating a bad point. Q: Does this correct for sample dilution? A: Yes. The curve gives the concentration in the diluted well, and the tool multiplies that by the dilution factor you enter to report the concentration in the original undiluted sample. Set the factor to 1 if the sample was run neat. #### Flow Cytometry Compensation Matrix Calculator URL: https://geratools.com/flow-cytometry-compensation Calculate flow cytometry spillover values from single-stain control MFI readings to build a compensation matrix for a two-colour panel. Subtracts unstained background and reports each leak as a percent of the source signal. Built for immunology and clinical flow labs. Runs in your browser. How to use: 1. Run single-stain controls: Acquire one single-stain control per fluorophore and read the median fluorescence of the positive and negative populations in each detector. 2. Enter the eight MFI values: For each control type the positive and negative MFI in its own detector and in the other dye's detector so background can be subtracted. 3. Read the spillover: The tool divides the net leak signal by the net source signal to give each off-diagonal spillover percent, with the diagonal fixed at 100 percent. FAQ: Q: What is compensation in flow cytometry? A: Fluorophores emit light over a broad spectrum, so a dye meant for one detector also produces signal in others. Compensation subtracts that spillover so each channel reports only its true fluorophore. Getting it right is essential before any multi-colour panel can be interpreted. Q: How is spillover calculated? A: From a single-stain control, spillover into another detector is the net positive signal seen in that detector divided by the net positive signal in the dye's own detector, as a percent. Net means the positive median minus the unstained negative median, which removes autofluorescence and background. Q: Why use the median and not the mean? A: Fluorescence distributions are skewed and span several logs, so the arithmetic mean is pulled by bright outliers. The median fluorescence intensity, or MFI, is robust to that skew and is the standard statistic for compensation and for reporting populations. Q: What spillover value is too high? A: Low single-digit spillover is trivial to compensate. Values into the tens of percent are common between adjacent dyes like FITC and PE and still work. Spillover much above 50 percent means heavy spectral overlap and large spreading error, so a different dye pairing is usually the better fix. Q: Do I subtract the unstained control? A: Yes, always. Autofluorescence and instrument background add a baseline to every detector. The calculator subtracts the negative-population MFI you enter for each detector, so the spillover reflects only the dye-specific signal and not the cells' own glow. Q: My plot is properly compensated but the population still smears — why? A: That is spreading error, not a compensation fault. Compensation removes the median spillover exactly but cannot remove the photon-counting noise the spillover carries, which fans the compensated population into a wedge. The fix is a better dye pairing or a brighter fluorophore for the weak marker, never more compensation. #### Idaho Vehicle Registration Fee Calculator URL: https://geratools.com/idaho-vehicle-registration-fee-calculator Estimates Idaho passenger-vehicle registration fees from the age-based fee schedule in Idaho Code §49-402 (newer cars cost more), plus the one-time title fee, EV/hybrid surcharges, and county option fees, to project what you will owe at the Idaho DMV. How to use: 1. Select the vehicle age: Choose the age band that matches your car so the tool applies Idaho's age-tiered registration fee, where newer vehicles are charged the most. 2. Add title and optional fees: Keep the one-time title fee if you are titling the vehicle, and add any local option or postage fees your county charges. 3. Read the total: The tool sums the age-based registration fee, the title fee, and any extras to estimate your total cost at the Idaho DMV. FAQ: Q: How does Idaho set its registration fee? A: Idaho charges passenger cars and light trucks an annual registration fee based on the vehicle's age, not its value. Under Idaho Code §49-402, vehicles 1 to 2 years old pay the highest fee and the amount steps down as the car gets older, reaching a flat minimum for vehicles 7 years and older. Q: How much is the Idaho title fee? A: Idaho charges a one-time title fee of $14 to issue a certificate of title when ownership changes, separate from the annual registration. An expedited 'rush title' service costs extra. You only pay the title fee when titling the vehicle, not at each annual renewal. Q: Does Idaho tax vehicles by value? A: No. Unlike states with an annual ad valorem property tax on cars, Idaho's registration fee is a flat age-tiered amount and does not depend on the vehicle's market value. This keeps registration predictable, though sales tax is charged separately on the purchase price. Q: Are there extra local fees in Idaho? A: Some Idaho counties add a voter-approved local vehicle registration fee — Ada County is the best-known example — and there is a small per-transaction administrative charge. Use the optional fees field to add them for a more complete estimate. Q: Do electric vehicles pay more to register in Idaho? A: Yes. Because EVs buy no taxed gasoline, Idaho adds a flat annual fee for all-electric vehicles and a smaller one for plug-in hybrids on top of the normal age-based registration fee. Check the current amounts on the Idaho DMV fee page before renewing. #### INR from PT Ratio & ISI Calculator URL: https://geratools.com/international-sensitivity-index-pt Calculates the International Normalised Ratio from a measured prothrombin time ratio and the reagent-specific International Sensitivity Index using INR equals the PT ratio raised to the ISI. For coagulation laboratory scientists standardising anticoagulation monitoring. How to use: 1. Enter the prothrombin times: Type the patient's prothrombin time in seconds and the mean normal prothrombin time for your reagent and analyser. 2. Enter the reagent ISI: Enter the International Sensitivity Index printed on the thromboplastin reagent insert for the lot in use. 3. Read the INR: The tool computes the PT ratio and raises it to the ISI to give the standardised INR, with a flag if the value falls in or above the usual therapeutic range. FAQ: Q: What is the INR formula? A: The INR equals the patient PT ratio raised to the power of the reagent ISI: INR = (patient PT / mean normal PT)^ISI. The mean normal prothrombin time (MNPT) is the geometric mean of PTs from at least 20 healthy donors for that reagent and instrument combination. Q: Why is the ISI needed? A: Different thromboplastin reagents have different sensitivities to the clotting factor reductions caused by warfarin. The ISI calibrates each reagent against the international reference thromboplastin, so applying it makes results comparable between laboratories regardless of which reagent was used. Q: Can I enter a PT ratio directly? A: Yes. If you already have the PT ratio, set the mean normal PT to 1 and enter the ratio as the patient PT, since the ratio of those equals the ratio itself. Otherwise enter both prothrombin times and the tool computes the ratio for you. Q: What is a typical therapeutic INR? A: Most warfarin indications target an INR of 2.0 to 3.0, with some mechanical heart valves targeting 2.5 to 3.5. The tool flags values within and above the common 2.0 to 3.0 range as a convenience, but the correct target depends on the indication. Q: Does the INR apply to direct oral anticoagulants? A: No. The INR is validated only for monitoring vitamin K antagonists such as warfarin. It is unreliable for direct oral anticoagulants like apixaban or rivaroxaban, which require drug-specific assays where monitoring is needed. #### LSAT Score Percentile Calculator URL: https://geratools.com/lsat-score-percentile-calculator Enter your LSAT score to see the approximate LSAC percentile rank — based on multi-year rolling test-taker data — plus comparison to median scores for top law school tiers. How to use: 1. Enter your LSAT score: Type your scaled LSAT score between 120 and 180. 2. Read the percentile: The tool returns the approximate national percentile rank from LSAC rolling data. 3. Compare to school tiers: Check the median-score reference to gauge competitiveness for different law school tiers. FAQ: Q: What does an LSAT percentile mean? A: Your LSAT percentile is the percentage of test-takers who scored at or below your scaled score over the most recent multi-year reporting window. A 90th percentile score means you outperformed about 90% of test-takers. Q: What is a good LSAT score? A: Scores above 160 are roughly the 80th percentile and above, and 170+ lands near the 97th percentile. The median LSAT score is about 152, which sits near the 50th percentile. Q: Why is the scale 120 to 180? A: The LSAT uses a scaled score from 120 (lowest) to 180 (highest). Raw correct answers are equated across test forms onto this fixed scale so scores are comparable across administrations. Q: Are these percentiles exact? A: These are close approximations of published LSAC percentile bands and shift slightly each year as the rolling test-taker pool changes. Use them as a strong estimate, not an official LSAC report. Q: Does a higher LSAT really matter for admissions? A: Yes — the LSAT is one of the two heaviest factors (with GPA) in law school admissions and scholarship decisions. Even a few points can move you across tier medians and change merit aid offers significantly. #### Red Cell Indices (MCV, MCH, MCHC) Calculator URL: https://geratools.com/mean-corpuscular-volume-indices Calculate MCV, MCH, and MCHC from haemoglobin, haematocrit, and red cell count, then classify anaemia as microcytic, normocytic, or macrocytic with a differential-diagnosis prompt. For haematology and primary care. How to use: 1. Enter the CBC values: Provide haemoglobin in g/dL, haematocrit as a percentage, and red cell count in 10 to the 12 per litre from the full blood count. 2. Let it compute the indices: The tool derives MCV, MCH, and MCHC from the standard formulae and compares each against its reference range. 3. Read the classification: It labels the anaemia as microcytic, normocytic, or macrocytic and lists the differential diagnoses worth considering for that pattern. FAQ: Q: How are MCV, MCH, and MCHC calculated? A: MCV equals haematocrit percent divided by red cell count, times ten. MCH equals haemoglobin divided by red cell count, times ten. MCHC equals haemoglobin divided by haematocrit percent, times one hundred. All three are derived from the three CBC values you enter. Q: What is the difference between MCH and MCHC? A: MCH is the average mass of haemoglobin per red cell, measured in picograms. MCHC is the concentration of haemoglobin within the cell volume, measured in g/dL. MCH scales with cell size, while MCHC reflects how densely each cell is packed with haemoglobin. Q: How does MCV classify anaemia? A: MCV below 80 femtolitres is microcytic, pointing to iron deficiency or thalassaemia. MCV between 80 and 100 is normocytic, seen in acute blood loss or chronic disease. MCV above 100 is macrocytic, suggesting B12 or folate deficiency, alcohol, or liver disease. Q: What does a high MCHC mean? A: A genuinely high MCHC is unusual because there is a ceiling to how much haemoglobin fits in a cell. It most often signals hereditary spherocytosis or a laboratory artefact such as cold agglutinins, lipaemia, or a measurement error, so it warrants a check rather than a diagnosis. Q: Do these indices replace a blood film? A: No. The indices give averages that narrow the differential quickly, but they hide mixed populations. A blood film, reticulocyte count, and iron or vitamin studies are still needed to confirm the cause. Reference ranges also vary by laboratory, age, and sex. #### Bellows Draw Magnification Ratio Table URL: https://geratools.com/photographic-bellows-magnification Produce a table of magnification ratios, effective aperture, and exposure compensation in stops across a range of bellows extensions for a given lens focal length. A ready reference for macro studio work. Runs in your browser. How to use: 1. Enter the lens focal length and aperture: Type the focal length in millimetres and the aperture you have set on the lens. 2. Set the extension range: Choose the start and end bellows draw beyond infinity, plus a step size, to control how many rows the table produces. 3. Read the table: Each row shows magnification, reproduction ratio, effective f-number, and the extra stops of exposure your meter must add for that draw. FAQ: Q: How is bellows magnification calculated? A: Magnification equals the bellows extension beyond infinity divided by the lens focal length. A 100 mm lens drawn out an extra 100 mm reaches 1.0 times, or 1:1 life-size reproduction. Q: What is the bellows factor and effective aperture? A: As the lens extends, the same f-stop passes less light to the larger image. The effective f-number is the marked f-number times (magnification plus one), so an f/8 lens at 1:1 behaves like f/16. Q: How many extra stops do I need at a given magnification? A: The exposure compensation in stops is two times the base-2 logarithm of (magnification plus one). At 1:1 that is exactly two stops; at 0.5 times it is about 1.17 stops. The table lists this for every row. Q: What does extension beyond infinity mean? A: It is the amount the bellows is drawn out past the lens position that focuses at infinity. That additional draw, not the total bellows length, sets the magnification, so the tool asks for the extra extension. Q: Does through-the-lens metering already account for this? A: Yes. A camera that meters through the lens automatically includes the bellows factor. The table is for hand-held meters, flash exposure, and large-format work where you set exposure manually. #### Primer Tm (Melting Temperature) Calculator URL: https://geratools.com/primer-tm-calculator Calculate PCR primer melting temperature from its sequence using the basic 2(A+T)+4(G+C) rule, the salt-adjusted Marmur formula, and SantaLucia nearest-neighbour thermodynamics with salt and primer concentration. For molecular biology and assay design. How to use: 1. Paste your primer sequence: Enter the primer 5 prime to 3 prime using only A, C, G, and T bases; spaces are ignored. 2. Set salt and primer concentration: Provide the monovalent cation concentration in mM and the primer concentration in nM used in your reaction. 3. Read the melting temperatures: The tool shows the nearest-neighbour Tm plus the basic and salt-adjusted estimates and the primer length and GC content. FAQ: Q: What is primer melting temperature? A: The melting temperature, or Tm, is the temperature at which half of the primer-template duplexes have separated into single strands. It guides the annealing temperature of a PCR, since primers must bind their target but not stick non-specifically. Q: Which method is most accurate? A: Nearest-neighbour thermodynamics is the most accurate because it accounts for how each adjacent base pair stacks, plus salt and primer concentration. The basic 2(A+T)+4(G+C) rule is only a rough guide for very short oligos under about 14 bases. Q: What annealing temperature should I use? A: A common starting point is 3 to 5 degrees below the lower Tm of your two primers. If you see non-specific bands, raise the annealing temperature; if the product is weak or absent, lower it and optimise from there. Q: Why does salt concentration matter? A: Monovalent cations such as sodium and potassium shield the negatively charged DNA backbone, stabilising the duplex and raising the Tm. Higher salt gives a higher Tm, which is why the nearest-neighbour calculation includes a salt correction term. Q: Should my two primers have matched Tm values? A: Yes. Forward and reverse primers should have Tm values within about 5 degrees of each other so they anneal efficiently at the same temperature. A large mismatch means one primer binds poorly at the chosen annealing temperature, hurting yield and specificity. #### Scope 3 Business Travel Emissions Calculator URL: https://geratools.com/scope3-business-travel-calculator Enter trips by mode (flight cabin class, rail, car type, taxi, hotel nights) and quantities to compute total Scope 3 Category 6 business travel CO2e using DEFRA 2024 emission factors. Produces a per-line breakdown for your GHG inventory and CSRD travel disclosure. How to use: 1. Add each leg of travel: Pick the transport mode and cabin class, then enter the distance in passenger-km (or room-nights for hotels). 2. Add more trips as needed: Use the add-trip button to build up a full itinerary across flights, rail, road, and accommodation. 3. Read the total CO2e: The calculator multiplies each quantity by its DEFRA emission factor and sums the result in kg and tonnes CO2e, with a per-line breakdown. FAQ: Q: What is Scope 3 Category 6? A: Category 6 of the GHG Protocol Scope 3 standard covers emissions from employee business travel in vehicles not owned or operated by the company — flights, trains, rental cars, taxis, and associated hotel stays. It is one of the 15 Scope 3 categories. Q: Where do the emission factors come from? A: The factors are kg CO2e per passenger-km (or per room-night) drawn from the UK DEFRA/BEIS 2024 greenhouse gas conversion factors. Flight factors include a radiative-forcing uplift to capture non-CO2 high-altitude warming effects. Q: Why does business-class flying emit more? A: Premium cabins allocate more aircraft floor space per passenger, so each traveller carries a larger share of the flight's total emissions. DEFRA applies multipliers, making long-haul first class roughly four times the economy factor per km. Q: Should I use distance or spend? A: Distance-based calculation (passenger-km) is more accurate and is preferred under the GHG Protocol. Spend-based factors are a fallback when you only have expense data. This tool uses the distance method. Q: Does this cover hotel stays? A: Yes. Accommodation is part of Category 6 business travel. The tool applies a per-room-night factor for a UK-average hotel; for other countries the factor varies, so adjust if you have location-specific data. #### Soap Recipe Oil Percentage Calculator URL: https://geratools.com/soap-batch-oil-percentage-calculator Enter oil types and target percentages to estimate hardness, cleansing, conditioning, bubbly, creamy, INS, and iodine values for your cold-process soap recipe, with recommended ranges flagged in colour. How to use: 1. Add your oils: Pick each oil in your recipe from the list and enter its percentage of the total oil weight. Add or remove rows until the recipe is complete. 2. Aim for 100 percent: Adjust the percentages so they sum to 100. The tool normalises automatically but a 100 percent total keeps your recipe honest. 3. Read the predicted qualities: The calculator shows hardness, cleansing, conditioning, bubbly, creamy, INS, and iodine, colouring each value by whether it falls inside the commonly recommended range. FAQ: Q: What do hardness, cleansing, and conditioning mean? A: Hardness predicts how firm and long-lasting the bar is, cleansing reflects how strongly it strips oils (too high can be drying), and conditioning estimates how moisturising and gentle the lather feels on skin. Each is a weighted average of the fatty acid profiles of your oils. Q: What is the INS number? A: INS is a hardness index derived from each oil's saponification and iodine values. It correlates with how hard and well-lathering a bar will be. A blended recipe with an INS near 160 tends to produce a balanced, durable bar, with a commonly cited target range of about 136 to 165. Q: What are good ranges for each property? A: Widely used targets are hardness 29 to 54, cleansing 12 to 22, conditioning 44 to 69, bubbly 14 to 46, creamy 16 to 48, and iodine 41 to 70. The tool flags any value outside its range so you can rebalance before mixing. Q: Is this a lye calculator? A: No. This estimates the sensory and structural qualities of your oil blend. It does not calculate the sodium hydroxide or potassium hydroxide needed for saponification. Always run a separate lye or SAP calculation with your chosen superfat before making soap. Q: Why limit castor oil to about 5 percent? A: Castor oil dramatically boosts bubbly and creamy lather, but above roughly 5 to 8 percent it makes the bar soft, sticky, and slow to cure. A small amount goes a long way, which is why most recipes keep it low. #### Soil Cation Exchange Capacity & Base Saturation Tool URL: https://geratools.com/soil-cation-exchange-capacity-tool Converts soil-test Ca, Mg, K, and Na in ppm to milliequivalents per 100 g using each cation's equivalent weight, sums them with exchangeable acidity to give CEC, computes individual and total base saturation percentages, and estimates a lime requirement from buffer pH. A soil-report interpretation aid for agronomists. How to use: 1. Enter cation ppm: Type the soil-test values for calcium, magnesium, potassium, and sodium in parts per million from your lab report. 2. Add acidity and buffer pH: Enter exchangeable acidity in meq per 100 g (or leave zero) and the buffer pH if your lab reported one, plus your target pH. 3. Read CEC and saturation: The tool converts each cation to meq per 100 g, sums the CEC, shows base saturation for each nutrient, and estimates a lime requirement. FAQ: Q: How are ppm values converted to meq per 100 g? A: Divide the ppm value by the cation's equivalent weight and then by 10 to scale ppm to a per-100-gram basis. The equivalent weights are 200 for calcium, 120 for magnesium, 390 for potassium, and 230 for sodium, which already build in the 10x scaling, so meq/100g equals ppm divided by these factors. Q: What is base saturation? A: Base saturation is the percentage of the cation exchange capacity occupied by the base cations calcium, magnesium, potassium, and sodium rather than by acidity (hydrogen and aluminium). Higher base saturation generally means a less acidic, more fertile soil. Q: What are ideal base saturation ratios? A: A commonly cited balanced target is roughly 65 to 75 percent calcium, 10 to 15 percent magnesium, 2 to 5 percent potassium, and under 3 percent sodium. These ratios are guidelines; sufficiency levels of each nutrient matter more than hitting exact percentages. Q: How is the lime requirement estimated? A: When a buffer pH is provided, the tool estimates lime need from the gap between buffer pH and a reference, since a lower buffer pH means more reserve acidity to neutralize. This is an approximation; use your lab's specific buffer method and recommendation for field rates. Q: What is a typical CEC value? A: Sandy soils often have a CEC of 1 to 5 meq per 100 g, loams 5 to 15, and clay or high-organic-matter soils 15 to 30 or more. A higher CEC means the soil can hold more nutrients against leaching but also needs more lime to shift pH. #### Sulfate to Chloride Ratio Calculator URL: https://geratools.com/sulfate-chloride-ratio Compute the sulfate-to-chloride (SO4:Cl) ratio from your brewing water values and classify the balance — hop-forward, balanced, or malty. Guide salt additions toward the flavour character you want. Runs 100% in your browser. How to use: 1. Enter your sulfate and chloride: Type the sulfate (SO4) and chloride (Cl) concentrations of your treated brewing water in parts per million (ppm), usually from a water report plus any salt additions. 2. Read the ratio: The calculator divides sulfate by chloride to give the SO4:Cl ratio and classifies it as malty, balanced, or hop-forward. 3. Adjust to taste: Add gypsum to push sulfate up for hoppy beers, or calcium chloride to push chloride up for malty beers, then recheck the ratio against your target style. FAQ: Q: What is the sulfate-to-chloride ratio? A: It is the concentration of sulfate (SO4) divided by the concentration of chloride (Cl) in your brewing water, both in ppm. It strongly influences perceived balance: sulfate accentuates hop bitterness and dryness, while chloride accentuates malt fullness and sweetness. Q: What ratios suit different beers? A: A ratio above roughly 2:1 is hop-forward (good for IPAs and bitters), around 1:1 is balanced, and below about 0.5:1 is malt-forward (good for stouts, milds, and malty lagers). These are guidelines, not hard rules. Q: How do I raise sulfate or chloride? A: Gypsum (calcium sulfate) raises sulfate; calcium chloride raises chloride. Both also add calcium. Add small amounts, recalculate, and aim for total sulfate and chloride levels that suit the style, not just the ratio. Q: Is a higher ratio always more bitter? A: Not exactly. The ratio shifts perceived balance toward dryness and hop crispness, but it does not change the actual IBU. Very high sulfate can also taste minerally or harsh, so extreme ratios are best avoided. Q: Does my water data leave my device? A: No. The calculation runs entirely in your browser and nothing you enter is uploaded or stored. #### Weld Joint Preparation Calculator URL: https://geratools.com/weld-joint-prep-calculator Recommend the included groove angle, root face, and root opening for AWS D1.1 prequalified butt, T, and corner joints based on material thickness and process, and draw the cross-section as an SVG diagram for fit-up reference. How to use: 1. Pick the joint type: Choose a butt, T, or corner joint to set the base groove geometry. 2. Enter thickness and process: Type the material thickness in millimetres and select the welding process, which influences root face and opening. 3. Read the prep and diagram: The tool returns the included angle, root face, and root opening, draws the cross-section, and flags when a double-sided prep is preferred. FAQ: Q: What is the root face on a weld joint? A: The root face, also called the land, is the flat unbevelled edge at the bottom of the groove. It controls how much metal the root pass must fuse through. A larger root face supports the puddle and resists burn-through but needs a more penetrating process or a back-gouge. Q: What is the root opening for? A: The root opening is the gap between the two parts at the bottom of the joint. It gives the arc access to the root so the weld fully penetrates. Too small a gap risks lack of fusion at the root; too large a gap risks burn-through and wastes filler. Q: Why is a 60 degree groove angle common? A: A 60 degree included angle gives the electrode enough access to fuse both bevel faces and the root while keeping the volume of deposited metal reasonable. Narrower angles save filler but risk lack of sidewall fusion; wider angles fuse easily but cost more weld metal and distortion. Q: When should I use a double-V instead of a single-V? A: Above roughly 25 mm of thickness a double-V or double-bevel prep is preferred. Welding from both sides roughly halves the volume of a single-V, balances the shrinkage so the plate stays flatter, and reduces total filler and distortion. Q: Does submerged arc need a different prep? A: Yes. Because submerged arc penetrates deeply, it tolerates a larger root face and often a closed root, so less of the joint must be bevelled. This calculator increases the root face and closes the gap when you select the SAW process. #### Multi-Pass Weld Sequence Planner URL: https://geratools.com/weld-pass-sequence-calculator Estimates how many weld passes fill a V-groove or U-groove joint from its cross-sectional area, weld process (SMAW, GMAW, FCAW), and electrode or wire diameter. Breaks the result into root, fill, and cap passes and suggests a backstep or balanced sequence to control distortion. Runs in your browser. How to use: 1. Describe the joint: Enter the plate thickness or groove depth, the root gap, and the included groove angle of the bevel. 2. Set the process: Choose SMAW, GMAW, or FCAW and enter the electrode or wire diameter, or override the deposited area per pass directly. 3. Read the plan: The tool computes the fill area, the pass count split into root, fill, and cap, and a suggested distortion-control sequence. FAQ: Q: How is the number of passes calculated? A: The tool finds the weld cross-sectional area from the groove geometry, adds a cap allowance, then divides by the deposited area per pass and rounds up. More fill area or smaller passes means more passes. Q: How is the groove cross-section found? A: For a single-V groove it sums a rectangular root channel, root gap times depth, with the triangular bevel area, depth squared times the tangent of the half-angle. Wider angles and deeper grooves both raise the area sharply. Q: What is a backstep sequence and why use it? A: In a backstep sequence you weld short segments in the direction opposite overall travel. Each segment shrinks toward the previous one, so the accumulated pulling distributes evenly and angular distortion drops on thicker joints. Q: Why split passes into root, fill, and cap? A: The root pass fuses the joint and sets penetration, fill passes build the bulk, and the cap shapes the reinforcement and finish. Planning the split helps you choose technique, amperage, and interpass cleaning for each stage. Q: How accurate is the deposited area per pass? A: It is an estimate scaled from process and wire diameter, since real deposition depends on amperage, travel speed, and deposition efficiency. Override it with your measured bead area for a tighter pass count. #### Western Blot Sample Preparation Calculator URL: https://geratools.com/western-blot-sample-loading Enter measured protein concentrations for several lysates and a target protein mass per lane to get the sample volume, added water, and loading buffer for each well so every lane carries equal protein on an SDS-PAGE western blot. For molecular and cell biologists. How to use: 1. Enter target and buffer strength: Set the protein mass you want per lane (for example 20 µg), the final well volume, and the loading buffer concentration (such as 4×). 2. Add each sample's concentration: For every lysate, enter its measured protein concentration from your BCA or Bradford assay. Add as many samples as you have lanes. 3. Read the pipetting table: Each row gives the lysate volume, water to top up, and loading buffer to add so that every lane carries the same protein mass in the same final volume. FAQ: Q: How is the sample volume calculated? A: Sample volume equals target mass divided by measured concentration. To load 20 µg from a 2 µg/µL lysate you pipette 10 µL. Lower-concentration samples need more volume, so the calculator also checks each fits in the well. Q: How much loading buffer do I add? A: Loading buffer is added to reach 1× in the final volume. For a 4× buffer in a 20 µL well you add 5 µL (one quarter), since 4× diluted four-fold becomes 1×. The remaining volume after sample and buffer is made up with water. Q: What if a sample is too dilute to fit the well? A: If the required lysate volume plus the loading buffer already exceeds the final well volume, you cannot reach the target mass at that well size. The calculator flags the sample so you can concentrate it, lower the target, or use a larger well. Q: Why normalise to equal protein per lane? A: Western blot band intensity is only comparable across lanes if each carries the same total protein. Equal loading lets you attribute differences in band signal to the target protein's abundance rather than to how much lysate you happened to load. Q: Should I still run a loading control? A: Yes. Even with careful normalisation, assays and transfers vary. A housekeeping loading control such as GAPDH, β-actin, or total-protein stain confirms equal loading and lets you correct the signal if needed. #### XY Steps-Per-mm Calibration Calculator URL: https://geratools.com/xy-steps-calibration Computes corrected steps-per-mm for the X and Y axes of a 3D printer or CNC using new steps = current steps times commanded distance divided by actual measured distance. Removes dimensional inaccuracy so printed parts come out the right size. How to use: 1. Command a known move: Tell the printer to move the axis a set distance, for example 100 mm, from a marked start position. 2. Measure the actual movement: Use calipers or a steel rule to measure how far the axis really travelled, then enter the commanded and actual distances. 3. Read the corrected steps/mm: Enter your current steps/mm value and the tool returns the corrected figure to set in firmware so future moves are exact. FAQ: Q: What does steps-per-mm mean? A: It is the number of stepper motor microsteps the firmware sends to move an axis exactly one millimetre. If this value is slightly wrong, every move is scaled by the same percentage, so a part comes out consistently too big or too small. Q: What is the calibration formula? A: New steps per mm equals current steps per mm times commanded distance divided by actual measured distance. If you asked for 100 mm but got 98.5 mm, the axis under-moved, so the new value is the current one multiplied by 100 divided by 98.5, a small increase. Q: How far should I command the test move? A: A longer move gives a more accurate result because measurement error becomes a smaller fraction of the total. 100 mm is a good practical distance for most printers; for CNC machines 200 mm or more reduces the impact of caliper reading error. Q: Why measure with calipers and not a ruler? A: The whole point of calibration is sub-millimetre accuracy, so the measuring tool must be more precise than the error you are correcting. Calipers read to 0.01 or 0.02 mm; a printed ruler is only good to about 0.5 mm and would defeat the exercise. Q: Do I calibrate X and Y separately? A: Yes. The two axes use independent belts, pulleys and motors, so they can drift by different amounts. Calibrate each one with its own test move and enter its own current value, which is why this tool has separate fields for X and Y. #### Mean, Median & Mode Calculator URL: https://geratools.com/average-mean-median-mode Free average calculator — paste a list of numbers and instantly get the mean, median, mode, range, sum and count. Runs entirely in your browser, nothing is uploaded. How to use: 1. Paste your numbers: Enter your data as a list of numbers separated by commas or spaces. 2. Read the statistics: The mean, median, mode, range, sum and count all update instantly below. FAQ: Q: What is the difference between mean, median and mode? A: The mean is the arithmetic average (sum divided by count). The median is the middle value when the numbers are sorted. The mode is the value that appears most often — there may be none, one, or several. Q: What happens if there is no mode? A: If every value appears the same number of times, there is no mode and the tool shows "none". If several values tie for most frequent, all of them are listed. Q: Is my data uploaded anywhere? A: No — every statistic is computed entirely in your browser, and the numbers you paste are never uploaded. #### Time Duration Adder URL: https://geratools.com/time-duration-adder Free time duration calculator. Add or subtract any number of H:M:S durations and get the total in HH:MM:SS, total seconds and decimal hours. Privacy-first — everything runs in your browser and nothing is sent anywhere. How to use: 1. Enter each duration: For each row, choose add or subtract and type the hours, minutes and seconds. 2. Add more rows: Use "Add duration" for as many entries as you need, and remove any row with the ✕ button. 3. Read the total: The result shows the combined duration as HH:MM:SS, plus total seconds and decimal hours. FAQ: Q: Can the total be negative? A: Yes. If the durations you subtract are larger than the durations you add, the total is shown with a minus sign so you can see the shortfall. Q: How accurate is the calculation? A: It is exact integer arithmetic. Each duration is converted to whole seconds, summed with its sign, and re-expanded to hours, minutes and seconds with no rounding loss. Q: Are my durations sent anywhere? A: No. The tool is privacy-first — every value you type stays in your browser and is never uploaded to a server. Q: What is decimal hours and why is it shown? A: Decimal hours expresses the total as a single number of hours — for example 2 hours 30 minutes is 2.5 hours. It is the form most billing and payroll systems expect. Q: How many durations can I add? A: As many as you like. Use Add duration to insert new rows, and remove any row with its delete button; the total updates instantly. Q: Can minutes or seconds exceed 60? A: Yes. You can enter 90 minutes or 120 seconds and the tool normalises the total correctly — 90 minutes becomes 1 hour 30 minutes in the result. Q: What is this useful for? A: Totalling billable time, summing audio or video clip lengths, adding training-session times, and netting project hours against a budget. #### Acceleration Calculator URL: https://geratools.com/acceleration-calculator Free acceleration calculator using a = (v_f − v_i) ÷ t. Solve for acceleration, initial or final velocity, or time. Runs entirely in your browser with no uploads. How to use: 1. Choose what to solve for: Select acceleration, initial velocity, final velocity, or time — the tool rearranges the kinematics equation for you. 2. Enter the known values: Provide the remaining quantities in SI units (metres per second, seconds, metres per second squared). 3. Read the result: The answer appears instantly with its unit. FAQ: Q: What is the acceleration formula? A: Average acceleration is the change in velocity divided by the time taken, a = (v_f − v_i) ÷ t. With velocity in metres per second and time in seconds, the result is in metres per second squared. Q: Can acceleration be negative? A: Yes. A negative acceleration (deceleration) means the object is slowing down, which happens when the final velocity is less than the initial velocity. Q: What units should I use? A: Use SI units for a clean result — velocity in metres per second (m/s) and time in seconds (s), which gives acceleration in metres per second squared (m/s²). If you enter km/h or other units, convert them first. Q: What is the difference between average and instantaneous acceleration? A: This tool computes average acceleration — the total change in velocity divided by the total time. Instantaneous acceleration is the value at a single moment, found by differentiating velocity, and requires calculus rather than this simple ratio. Q: How do I find final velocity from acceleration? A: Rearrange the same equation to v_f = v_i + a·t. Select "final velocity" in the tool and enter the initial velocity, acceleration and time. Q: Is my data sent anywhere? A: No. All calculations run locally in your browser and nothing is uploaded. #### Date Duration Calculator URL: https://geratools.com/date-duration-calculator Free date duration calculator. Get the exact years, months, days, hours and minutes between two datetimes, plus totals in weeks, days, hours and business days — or add and subtract a duration from any date. Runs entirely in your browser. How to use: 1. Choose a mode: Switch between 'Time between two dates' and 'Add / subtract a duration' using the toggle at the top. 2. Enter your dates and times: Pick a start and end datetime (or a base date plus a duration). Every field updates the result instantly. 3. Read the breakdown and totals: See the exact calendar breakdown, total weeks, days, hours, minutes and business days, then copy or save the result. FAQ: Q: How does the calculator work out the exact duration? A: It compares the two datetimes calendar unit by calendar unit — minutes, hours, days, months and years — borrowing from the next-larger unit where needed (for example a negative day count borrows the real number of days from the previous month). This gives a true calendar duration like '2 years, 3 months, 14 days' rather than a flat day count, which is why the breakdown respects leap years and uneven month lengths. Q: What is the difference between the breakdown and the totals? A: The breakdown splits the gap into years, months, days, hours and minutes. The totals re-express the same gap as a single unit each — total weeks, total days, total hours and total minutes — so you can answer questions like 'how many hours is that?' without doing the maths yourself. Q: How are business days counted? A: The tool walks every calendar day from the start to the end and counts only Monday to Friday, skipping Saturday and Sunday. It does not subtract public holidays, because those vary by country and region — treat the business-day figure as working days excluding weekends only. Q: What does 'include the end day' do? A: By default the duration is the gap between the two instants, so a Monday-to-Friday range is four days. Tick 'include the end day' to count both endpoints, which adds one day to the total — useful for things like hotel nights, project schedules or leave requests where both the first and last day count. Q: Can I add or subtract weeks, months and years at once? A: Yes. In the add/subtract mode you can combine years, months, weeks, days, hours and minutes in a single calculation. Months and years are applied as calendar units first (with day-of-month clamped to the last valid day, so 31 Jan minus one month lands on the correct end of February), then weeks, days, hours and minutes are applied exactly. Q: Is my data sent anywhere? A: No. Every calculation, your saved history and the CSV export all happen entirely inside your browser using JavaScript. Nothing is uploaded, logged or shared, so it is safe for confidential contract dates, medical timelines or anything else private. #### Aspect Ratio Crop & Letterbox Calculator URL: https://geratools.com/aspect-ratio-crop-calculator Free aspect ratio crop and letterbox calculator. Enter a source resolution and a target ratio (16:9, 9:16, 1:1, 4:5, 21:9) to get the cropped pixel size, how much of the frame survives, the bars needed to letterbox instead, and a storage cost for a whole batch. Runs entirely in your browser. How to use: 1. Enter your source resolution: Type the pixel width and height of your original image or video, or pick a preset such as 4K UHD (3840x2160) or a 3:2 DSLR frame. 2. Choose a target aspect ratio: Enter the target ratio width and height, or tap a preset like 16:9, 9:16 vertical, 1:1 square or 21:9 cinematic. Use Swap to flip orientation. 3. Read the crop and letterbox results: See the cropped pixel size for a fill (cover), how much frame area survives, and the alternative letterbox/pillarbox canvas if you would rather pad than crop. 4. Estimate the storage cost: Set bytes per pixel for your output format, the number of assets and a price per GB to estimate total size and monthly storage cost for the cropped batch. FAQ: Q: What is the difference between crop-to-fill and letterbox-to-fit? A: Crop-to-fill (cover) scales the source so it completely fills the target ratio, then trims the overflowing edges, so no bars appear but some pixels are discarded. Letterbox-to-fit (contain) scales the source so the whole frame is visible inside a target-ratio canvas, adding bars to pad the empty space, so nothing is lost but the picture no longer fills the screen. Q: How are the cropped dimensions calculated? A: The tool compares the source ratio (width divided by height) with the target ratio. If the source is wider than the target it keeps the full height and crops the sides to height times target ratio; if the source is taller it keeps the full width and crops the top and bottom to width divided by target ratio. Both outputs match the exact target aspect ratio. Q: When do I get letterbox bars versus pillarbox bars? A: You get letterbox bars (top and bottom) when your source is wider than the target ratio, for example fitting a 16:9 clip into a 1:1 square. You get pillarbox bars (left and right) when your source is narrower than the target, such as fitting a vertical 9:16 clip into a 16:9 frame. Q: How is the storage estimate worked out? A: It multiplies the cropped pixel area by a bytes-per-pixel figure for your chosen format (JPEG, WebP, PNG or raw RGBA), then by the number of assets to get total bytes. Dividing by 1024 cubed gives gigabytes, which is multiplied by your price per GB per month for a rough monthly storage cost. Real compressed sizes vary with content, so treat it as a planning estimate. Q: Does cropping reduce image quality? A: Cropping itself does not blur pixels, but it removes part of the frame, so the kept region is what fills the new ratio. The area-kept percentage tells you how much of the original survives. If you crop a 16:9 image to 9:16 you keep only the central strip, so you lose a large share of the width and may need to reframe the subject. Q: Is my image or data sent anywhere? A: No. This calculator only works with the numbers you type. Everything is computed locally in your browser using plain arithmetic, and no resolution, file or value is ever uploaded to a server. #### Percentage Calculator URL: https://geratools.com/percentage-calculator Free percentage calculator suite — what is X% of Y, X is what percent of Y, percent change, percent difference, increase or decrease a value, and reverse a percentage. Shows the working step by step. Runs entirely in your browser. How to use: 1. Choose the calculation: Pick the percentage question you need from the dropdown — of, is-what-%, change, difference, increase, decrease or reverse. 2. Enter the two numbers: The input labels rename themselves to match the mode, so you always know which box is the percent and which is the value. 3. Read the answer and the working: The headline result, a plain-English summary, and the step-by-step formula appear below. Use the Copy button to grab the answer. FAQ: Q: What is the difference between percent change and percent difference? A: Percent change has a direction and a reference point — it measures how much a number moved relative to its starting value: ((new − old) ÷ old) × 100. Percent difference has no direction: it compares two values of equal standing by dividing the gap by their average, (|X − Y| ÷ ((|X| + |Y|) ÷ 2)) × 100, so swapping X and Y gives the same answer. Q: How do I calculate what is X percent of Y? A: Convert the percent to a decimal and multiply: (X ÷ 100) × Y. For example, 15% of 200 is (15 ÷ 100) × 200 = 0.15 × 200 = 30. Use the "What is X% of Y?" mode and enter 15 and 200. Q: How do I work out a reverse percentage? A: Divide the final amount by (1 + change ÷ 100). A jacket costing 120 after a 20% increase started at 120 ÷ 1.20 = 100. For a discount, use a negative change: 80 after a −20% sale started at 80 ÷ 0.80 = 100. The reverse mode does this automatically. Q: Why does increasing by X% then decreasing by X% not return the original number? A: The two percentages are taken from different bases. Increase 100 by 20% and you get 120; decrease that 120 by 20% and you remove 24, landing on 96, not 100. To undo a 20% increase you must divide by 1.20, not subtract 20%. Q: How do I convert a percentage to a decimal or a fraction? A: Divide by 100 for the decimal — 15% = 0.15 — and place it over 100 for the fraction, 15/100, which simplifies to 3/20. The word percent literally means per hundred, so every percentage is already a fraction with a denominator of 100. Q: What happens if I divide by zero? A: The tool guards every division. Asking what percent X is of 0, or the percent change from a starting value of 0, has no meaningful answer, so the result shows a dash and the summary explains why instead of printing an error or Infinity. Q: Is anything I type uploaded? A: No. Every calculation runs in your browser with plain JavaScript arithmetic. No numbers are sent to a server, logged, or stored. #### Summation Calculator URL: https://geratools.com/summation-calculator Free online summation calculator. Enter any expression f(i) and bounds, or choose a built-in series type. See every term, partial sums, a sparkline, and the closed-form formula. Runs entirely in your browser. How to use: 1. Choose a series type: Pick Custom, Arithmetic, Geometric, Power, or Harmonic from the dropdown. Custom lets you type any expression in i. 2. Set the bounds: Enter the lower bound (often 1 or 0) and the upper bound. The calculator sums all integer values of i between them inclusive. 3. Enter the expression or parameters: For custom mode type something like i^2, 1/i, or 2*i-1. For built-in types fill in the first term plus the difference or ratio. 4. Read the result: The total sum appears immediately. Expand the term table or copy all results to clipboard with one click. FAQ: Q: What does the summation symbol (sigma) mean? A: The capital Greek letter sigma (S) followed by f(i) means "add up the values of f(i) as i takes every integer from the lower bound to the upper bound". For example, summing i^2 from i=1 to i=4 gives 1+4+9+16 = 30. Q: What is the formula for the sum of an arithmetic series? A: An arithmetic series has a constant difference d between terms. The sum of n terms is S = n/2 * (first + last), equivalently S = n/2 * (2a + (n-1)d) where a is the first term. For example, 1+3+5+7+9 has a=1, d=2, n=5, so S = 5/2 * (1+9) = 25. Q: How do you sum a geometric series? A: A geometric series multiplies each term by a constant ratio r. The finite sum of n terms starting at a is S = a * (1 - r^n) / (1 - r) when r is not equal to 1. When r = 1 every term equals a and S = a * n. An infinite geometric series converges only when the absolute value of r is less than 1, giving S = a / (1 - r). Q: What is the formula for the sum of the first n squares? A: The sum of i^2 from i=1 to n equals n*(n+1)*(2n+1) / 6. For n=10 that is 10*11*21/6 = 385. The calculator verifies this automatically; you can check by choosing Power with p=2 and bounds 1 to 10. Q: Why does the harmonic series diverge? A: The harmonic series 1 + 1/2 + 1/3 + ... grows without bound, just extremely slowly. Adding terms up to i=10 gives about 2.93; up to i=1000 gives about 7.49; up to i=1,000,000 gives about 14.4. Because terms never shrink fast enough, partial sums eventually exceed any fixed value. The calculator shows the partial sums so you can see the growth rate for yourself. Q: Can I sum a custom expression like 1/(i*(i+1))? A: Yes. In Custom mode enter the expression using i for the index and ^ for powers. Parentheses, +, -, *, and / all work. The expression is evaluated safely in-browser without any network call. Note that 1/(i*(i+1)) has the elegant closed form 1 - 1/(n+1), which you can verify by comparing the calculator result with that formula. #### Coffee-to-Water Ratio Calculator URL: https://geratools.com/coffee-to-water-ratio-calculator Free coffee-to-water ratio calculator. Dial in the ideal grams of coffee and water for pour-over, espresso, French press, AeroPress, cold brew, Moka pot and drip. Includes bloom guide, grind notes and a full reference table. 100% in-browser. How to use: 1. Choose your brew method: Select the method that matches your equipment — pour-over, French press, espresso, AeroPress, cold brew, Moka pot, drip, or custom. 2. Pick a strength preset or set a custom ratio: Choose Light, Balanced, or Strong — each maps to the industry-standard ratio range for that method. Select Custom to dial in any ratio from 1:1 to 1:30 with a slider. 3. Enter your quantity and solve: Tell the calculator what you know — grams of coffee (to find water), millilitres of water (to find coffee), or number of cups (to find both). 4. Read your recipe: The result panel shows coffee in grams and tablespoons, water in ml and fl oz, the active ratio, strength label, water temperature, grind setting, brew time, and bloom water if applicable. FAQ: Q: What is the golden ratio for coffee? A: The Specialty Coffee Association (SCA) recommends a "golden ratio" of roughly 1:18 — about 55 g of coffee per litre of water (or 1 gram of coffee per 18 g of water). In practice most home brewers land between 1:15 and 1:17 for a balanced cup. Espresso uses a far tighter ratio of around 1:2. Q: How many grams of coffee should I use for 250 ml of water? A: For a balanced pour-over or drip, divide 250 by 15 to get about 16–17 g of coffee. For a stronger French press you might use 18–20 g; for a lighter Chemex-style brew, 14 g works well. The calculator shows exact figures for each method. Q: Does the ratio change for espresso? A: Yes — espresso uses much less water relative to coffee. A standard "normale" shot targets a 1:2 ratio (e.g., 18 g of ground coffee yields roughly 36 g of liquid espresso in 25–30 seconds). A ristretto uses closer to 1:1.5; a lungo stretches to 1:3 or beyond. Q: Why does cold brew use more coffee? A: Cold brew extracts slowly over 12–24 hours at low temperature, so extraction efficiency is lower than hot methods. A typical ratio of 1:7 (concentrate) to 1:9 (ready-to-drink) compensates by using more grounds. The resulting concentrate is then diluted 1:1 with milk or water before serving. Q: What does the bloom step do? A: Blooming (pre-infusion) means pouring 2× the coffee mass in hot water over fresh grounds and waiting 30–45 seconds. CO2 escaping from recently-roasted coffee can otherwise create an uneven extraction. The bloom degasses the grounds so the main pour extracts evenly. It applies mainly to pour-over and drip methods. Q: How do I convert grams to tablespoons for coffee? A: One level tablespoon of ground coffee weighs approximately 5–6 g depending on grind size and how loosely it is scooped. The calculator uses 5.3 g per tablespoon as a practical average. For precision — especially with espresso or a kitchen scale — always measure by weight, not volume. #### Golden Ratio Typography Calculator URL: https://geratools.com/golden-ratio-typography-calculator Free golden ratio typography calculator. Enter your base font size and instantly get a full modular type scale, optimal line heights, and max line-width recommendations — all derived from φ (phi = 1.618…). Copy ready-to-paste CSS custom properties. Runs entirely in your browser. How to use: 1. Enter your base font size: Type the pixel size used for body text — usually 16px on the web. 2. Choose an output unit: Pick rem (recommended for accessibility) or px for absolute values. 3. Read the scale: Each row shows the font size, unitless line-height ratio, and optimal max-width for that step. 4. Preview a step: Click any row to see a live text preview rendered at exactly those values. 5. Copy the CSS: Hit "Copy all CSS" to paste the full set of custom properties into your stylesheet, or "Copy CSS" on a single row for just that step. FAQ: Q: What is the golden ratio in typography? A: The golden ratio (φ ≈ 1.618) is an irrational number that appears throughout nature and art. In typography it is used to derive harmonious relationships between font sizes, line heights, and line widths. A type scale built on φ feels visually balanced because each level is exactly 1.618× the one below it — the same proportion the eye naturally finds pleasing. Q: How is each font size in the scale calculated? A: Each step n uses the formula: size(n) = base × φⁿ. So step +1 = base × 1.618, step +2 = base × 1.618² = base × 2.618, and step −1 = base ÷ 1.618. Multiplying or dividing by φ at each step keeps every pair of adjacent sizes in the same ratio. Q: Why is the line-height ratio 1.618? A: Setting line-height = font-size × φ places the leading (space between baselines) in golden proportion to the cap height. For a 16px base that gives a line-height of about 25.9px. The result is a rhythm that feels open and easy to read without wasting vertical space — the whitespace between lines mirrors the ratio found in well-proportioned typefaces. Q: How is the optimal line width (measure) derived? A: Classic typographic guidance recommends 45–90 characters per line, with 66 as the sweet spot (Robert Bringhurst, "The Elements of Typographic Style"). The calculator uses measure = size × φ², which for a 16px base gives roughly 419px — wide enough for comfortable reading without the eye losing its place on the return. Adjust your container to match. Q: What does the step number mean? A: Step 0 is your chosen base size (body text). Positive steps (+1, +2…) are larger — headings and display sizes. Negative steps (−1, −2) are smaller — captions and fine print. This mirrors the convention in tools like Every Layout and Utopia. Q: Should I use rem or px? A: Rem is strongly recommended for accessibility. Rem values scale with the user's browser default font-size preference, so someone who has bumped their browser to 20px will see your type grow proportionally. Px values are fixed and override the user's preference — acceptable for print-like contexts but not for body text on the web. #### Time Duration Calculator URL: https://geratools.com/time-duration-calculator Free time duration calculator. Work out the elapsed time between two clock times (including overnight shifts) in hours, minutes and decimal hours, or add and subtract a H:M:S duration from a start time. Runs entirely in your browser. How to use: 1. Enter two times for a difference: Type a start and end time to see the elapsed hours and minutes. Tick the overnight box if the end time is on the next day. 2. Add or subtract a duration: In the second panel, enter a start time, choose add or subtract, and type the hours, minutes and seconds to shift by. 3. Read the result: Both panels update instantly with a formatted duration or a resulting clock time, including any day roll-over. FAQ: Q: How do I calculate hours between two times? A: Convert both times to minutes past midnight, subtract the start from the end, and if the result is negative add 24 hours (the shift crossed midnight). The calculator does this for you and also shows the answer in decimal hours and total minutes. Q: What does the overnight option do? A: When ticked, it forces the end time to be treated as the following day. This is useful for night shifts where, for example, 22:30 to 06:15 should be counted as roughly 7 hours 45 minutes rather than a negative span. Q: Can it handle results past midnight when adding time? A: Yes. If adding a duration pushes the clock past 24:00, the result shows the wrapped time along with a "+1 day" (or more) label so you can see how many days rolled over. ### Food, Cooking & Brewing #### Beeswax Food Wrap Recipe Calculator URL: https://geratools.com/beeswax-wrap-recipe-calculator Enter your fabric dimensions and recipe ratio of beeswax, pine resin, and jojoba oil to compute exact ingredient weights for DIY beeswax food wraps. For zero-waste crafters making reusable food storage at home. How to use: 1. Enter your fabric size: Type the width and height of one wrap and how many wraps you are making, in centimetres or inches. 2. Set the recipe ratio: Use the default beeswax-to-pine-resin-to-jojoba ratio, or adjust the parts to make your wraps firmer or tackier. 3. Read the ingredient weights: The tool calculates total fabric area, the coating mix needed, and the grams of beeswax, pine resin, and jojoba oil to melt together. FAQ: Q: What is a good beeswax wrap recipe ratio? A: A common, reliable ratio is about 4 parts beeswax, 1 part pine resin, and 1 part jojoba oil by weight. The beeswax forms the body, pine resin adds the tackiness that lets a wrap cling to itself, and jojoba keeps the coating flexible so it does not crack. Q: How much coating does fabric need? A: Roughly 0.04 to 0.05 grams of total coating mix per square centimetre of fabric gives a good saturation without being gummy. The tool uses about 0.045 g/cm2 and splits that mix into the three ingredients by your chosen ratio. Q: Do I need the pine resin? A: Pine resin (often sold as pine rosin) is what makes a wrap grip and seal when you warm it with your hands. You can make plain beeswax-and-oil wraps without it, but they cling far less. If you skip it, the wraps work more like a loose cover. Q: Why add jojoba oil? A: Jojoba oil keeps the hardened coating supple so it bends around a bowl without flaking. Without an oil, a beeswax-and-resin coating can become brittle in the fridge and crack along fold lines, shortening the wrap's life. Q: How do I apply the coating? A: Lay the fabric on parchment, sprinkle the melted or grated mix evenly, then melt it in with a low oven or an iron between parchment sheets. Spread thin and even, peel up while warm, and wave to cool. Re-coat lightly when the cling fades. #### Mash Efficiency Calculator URL: https://geratools.com/mash-efficiency-calc Computes conversion efficiency, lauter efficiency, and overall brewhouse efficiency from your grain bill, batch volume, and measured pre-boil and post-boil gravity readings. Pinpoints whether sparging or conversion is limiting your yield. How to use: 1. Enter your grain bill: Type the total grain weight and its average extract potential in PPG (points per pound per gallon). Most base malts are around 37 PPG. 2. Add your measured gravities and volumes: Enter the pre-boil gravity and volume, and the post-boil gravity and volume you measured with a hydrometer or refractometer. 3. Read the efficiencies: The tool reports brewhouse efficiency (final yield) and breaks it down so you can see whether conversion or sparging is the limiting step. FAQ: Q: What is brewhouse efficiency? A: Brewhouse efficiency is the percentage of the maximum theoretical sugar in your grain that actually ends up in the boil kettle as gravity points. It combines how well the mash converted starch to sugar and how much of that sugar you rinsed out during the lauter. Q: How is it calculated? A: Maximum points equal grain PPG times grain pounds. Actual points equal measured gravity points times volume in gallons. Brewhouse efficiency is actual points divided by maximum points, expressed as a percentage. The same idea applied to the post-boil reading confirms your final wort yield. Q: What is a good mash efficiency? A: Most all-grain homebrewers land between 65 and 80 percent brewhouse efficiency. Batch spargers often see 70 to 75 percent, fly spargers 75 to 85 percent. Brew-in-a-bag with a fine crush and a squeeze can also reach the mid 70s. Consistency matters more than a high number. Q: Why are my pre-boil and post-boil efficiencies different? A: They should be nearly identical, because boiling only removes water and concentrates the existing sugar. If they differ a lot, you likely mismeasured a volume or gravity, or your wort was not well mixed before sampling. Q: How do I improve low efficiency? A: A finer grain crush, a correct mash pH near 5.2 to 5.4, adequate mash time, and a more thorough sparge all raise efficiency. If conversion is fine but yield is low, focus on sparging; if even the mash gravity is low, focus on crush and mash chemistry. #### Sourdough Starter Feeding Calculator URL: https://geratools.com/sourdough-starter-feeding-calculator Work out precisely how much flour and water to feed your sourdough starter for a 1-1-1, 1-2-2 or custom ratio, and the resulting hydration. Runs entirely in your browser. How to use: 1. Choose your feeding ratio: Pick a preset such as 1-2-2 for an overnight feed at room temperature, or enter custom flour and water parts for a stiff or liquid starter. 2. Set how much starter to keep: Enter the amount of starter you want to keep, or switch to target mode and enter the total starter you need for baking day. 3. Read the weights: The calculator shows the flour and water to add, the total after feeding, and how much to discard first. FAQ: Q: What does a 1-2-2 sourdough feeding ratio mean? A: It means for every 1 part of starter you keep, you add 2 parts flour and 2 parts water by weight. So 50 g of starter is fed with 100 g flour and 100 g water, giving 250 g of starter at 100 percent hydration. A larger ratio like 1-5-5 dilutes the starter more and slows the rise, which is useful before a long fridge rest. Q: How much starter should I keep before feeding? A: Most home bakers keep 20 to 50 g and discard the rest, because a small amount needs far less flour to maintain and still doubles reliably. Use target mode if you need a specific total for a recipe, and the calculator back-solves how much to keep so nothing is wasted. Q: Does the feeding ratio change the hydration? A: The hydration of the fresh feed equals the water parts divided by the flour parts, so a 1-2-2 feed is 100 percent hydration. If you feed with more water than flour the starter becomes wetter and more active, and with less water it becomes a stiffer starter that ferments more slowly. Q: Why discard some starter each feed? A: Without discarding, the amount doubles every feed and you would need ever more flour to keep it healthy. Removing most of the starter keeps the food-to-microbe ratio high so the culture stays vigorous, and the discard can go straight into pancakes, crackers or crumpets. #### Yeast Starter Calculator URL: https://geratools.com/yeast-starter-calculator Calculate the dried malt extract weight and water volume for a 1–4 litre yeast starter to grow a liquid yeast pack to your target pitching cell count. Accounts for yeast age and viability decay. Runs in your browser. How to use: 1. Enter your target cell count: Type the billions of cells you need to pitch — get this from a pitch-rate calculator for your batch size and gravity. 2. Describe your yeast pack: Enter the pack's original cell count and its age in days; the tool reduces the viable starting cells for age. 3. Set the starter size: Choose a starter volume from 1 to 4 litres. The calculator estimates the cells grown and lists the DME and water needed at 1.037 gravity. FAQ: Q: How much DME does a yeast starter need? A: A standard starter targets a gravity of about 1.037, which needs roughly 100 grams of dried malt extract per litre of finished starter. So a 2-litre starter uses about 200 g of DME topped up to 2 litres with water. Q: How does this model yeast growth? A: It uses a simplified growth model based on the inoculation density: smaller starters relative to the yeast pitched grow proportionally more new cells. The tool estimates new growth per litre of starter and adds it to your viable starting cells to reach the final count. Q: How does yeast age affect the calculation? A: Liquid yeast loses viability over time — commonly modelled as about 21 to 25 percent of cells dying per month. The tool applies a daily decay to your pack's stated cell count, so an older pack starts with fewer viable cells and needs a bigger starter to compensate. Q: What gravity should a starter be? A: Around 1.030 to 1.040 is standard; 1.037 is a common target that grows yeast efficiently without stressing it. Much higher gravity stresses the yeast and produces fewer healthy cells, defeating the purpose of the starter. Q: Do I need a stir plate? A: A stir plate keeps yeast in suspension and oxygenates the starter, producing noticeably more cells than an unstirred starter of the same size. If you do not have one, swirl the flask frequently and consider a slightly larger starter to hit your target. #### Oven Temperature Converter URL: https://geratools.com/cooking-oven-temperature-converter Free oven temperature converter — switch between Fahrenheit, Celsius, fan/convection Celsius and UK gas marks for any recipe. Runs entirely in your browser; nothing is uploaded. How to use: 1. Enter a temperature: Type the oven temperature from your recipe and choose °C or °F. 2. Read every scale: See the equivalent conventional Celsius, Fahrenheit, fan/convection Celsius and UK gas mark. 3. Adjust for your oven: Use the fan figure if you have a fan or convection oven, which runs cooler than conventional. FAQ: Q: How do I convert a fan oven temperature? A: Set a fan oven about 20°C lower than a conventional recipe temperature for the same result. So a recipe at 180°C conventional becomes 160°C fan. The converter shows the fan figure automatically. Q: What gas mark is 180°C? A: 180°C is gas mark 4, the common "moderate oven" setting for cakes and roasts. 200°C is gas mark 6 and 220°C is gas mark 7 on the conventional Regulo scale. Q: How do I convert Celsius to Fahrenheit for the oven? A: Use °F = (°C × 9/5) + 32. For example 180°C = 356°F and 200°C = 392°F. The converter does this instantly along with the fan and gas-mark equivalents. Q: Is anything I type uploaded? A: No. The oven temperature converter runs entirely in your browser. The temperature you enter is converted locally and never sent to a server. #### Oven Temperature Converter URL: https://geratools.com/oven-temperature-converter Free oven temperature converter for Celsius, Fahrenheit and gas mark, with a fan-oven note. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose your starting unit: Pick Celsius, Fahrenheit or gas mark from the dropdown. 2. Enter the temperature: Type the temperature, or select a gas mark, and the equivalents update instantly. 3. Read all three values: Celsius, Fahrenheit and gas mark are shown side by side, with a fan-oven adjustment note. FAQ: Q: How do I convert a conventional oven temperature for a fan oven? A: As a rule of thumb, set a fan (convection) oven about 20 °C lower than the conventional temperature shown, since fans circulate heat more efficiently. Q: What is gas mark 4 in Celsius? A: Gas mark 4 is 180 °C (about 350 °F), a common moderate baking temperature. Q: What is 350 °F in Celsius for baking? A: 350 °F equals 176.7 °C, usually rounded to 180 °C, which is gas mark 4 — the standard temperature for many cakes, cookies and roasts. Q: What is a hot oven in gas mark? A: Gas mark 7 (220 °C / 425 °F) and gas mark 8 (230 °C / 450 °F) are considered hot ovens, used for bread, pastry and high-heat roasting. Gas mark 9 (240 °C) is very hot. Q: Does this send my data anywhere? A: No. All conversions run locally in your browser with no network requests. #### Cooking Unit Converter URL: https://geratools.com/cooking-unit-converter Free density-aware cooking unit converter. Convert cups, tbsp, tsp, ml, grams and ounces for flour, sugar, butter and more, then scale an entire recipe up or down. Runs entirely in your browser. How to use: 1. Pick your two units: In the quick converter, choose the unit you have (e.g. cups) and the unit you want (e.g. grams), then type the amount. 2. Choose the ingredient when crossing volume and weight: If you convert between a volume (cups, ml) and a weight (grams, oz), select the ingredient so the correct density is applied. Flour and honey weigh very differently per cup. 3. Build and scale a full recipe: Add each ingredient as a row, set a scale factor or tap a preset like x2, and read the new amounts plus exact gram and millilitre equivalents. Export to CSV or copy the scaled list. FAQ: Q: Why does one cup of flour weigh less than one cup of sugar? A: Because weight depends on density, not volume. A cup is a fixed volume of about 237 ml, but flour is light and airy at roughly 0.53 g/ml while granulated sugar is dense at about 0.85 g/ml. So a cup of flour is around 125 g while a cup of sugar is around 200 g. This converter stores a density for each ingredient and uses it whenever you cross between volume and weight, which is why it is far more accurate than a generic cup-to-gram table. Q: Which cup size does this tool use? A: It uses the US customary cup of 236.588 ml, which is the standard in most online recipes. The UK metric cup (250 ml) and the Australian cup (also 250 ml) are slightly larger, so if your recipe specifies one of those, convert via millilitres: enter the amount in ml directly rather than as cups. Tablespoon and teaspoon values follow the US convention of 14.79 ml and 4.93 ml respectively. Q: How accurate are the gram conversions? A: They are as accurate as the ingredient densities allow, which is typically within a few percent for baking. Real densities vary with how you scoop, sift and pack an ingredient. Spooned-and-levelled flour weighs less than scooped flour, and packed brown sugar weighs more than loose. For precise baking, weigh ingredients on a kitchen scale and treat these figures as a reliable starting point. Q: Can I scale a recipe up or down? A: Yes. Add every ingredient as a row in the recipe section, then set a scale factor. Tap a preset such as x0.5 to halve a recipe or x2 to double it, or type any factor like 1.5. Every amount, plus its gram and millilitre equivalent, updates instantly so you can cook for a different number of servings without manual maths. Q: Is my recipe data sent anywhere? A: No. The entire tool runs in your browser using JavaScript. Nothing you type is uploaded, and your ingredient list is saved only in your own browser via local storage so it is still there when you return. You can clear it any time with the Reset button. Q: How do I convert tablespoons to teaspoons or cups? A: These are all volume units, so the conversion is a fixed ratio that does not depend on the ingredient. One US tablespoon equals exactly three teaspoons, and one cup equals sixteen tablespoons or forty-eight teaspoons. Pick tablespoons as the from-unit and teaspoons or cups as the to-unit in the quick converter and you will get the exact answer instantly. #### Beer ABV Calculator URL: https://geratools.com/beer-abv-calculator Free homebrewing ABV calculator. Enter your original gravity (OG) and final gravity (FG) to get alcohol by volume, apparent attenuation and estimated calories per serving. Runs 100% in your browser. How to use: 1. Take an original gravity (OG) reading: Before pitching yeast, measure the gravity of your wort with a hydrometer or refractometer. Record the value — it should be above 1.000, typically 1.040–1.080 for most ale and lager styles. 2. Ferment and take a final gravity (FG) reading: When fermentation appears complete (stable hydrometer readings 2–3 days apart), measure the gravity again. This is your FG. 3. Enter OG and FG into the calculator: Type both values. The calculator instantly shows ABV, apparent attenuation and estimated calories for common serving sizes. 4. Choose a formula if needed: The standard formula works well for most beers under 8% ABV. Switch to the alternate Balling formula for high-gravity beers above 8%. FAQ: Q: What is the formula for beer ABV from OG and FG? A: The most common formula is ABV = (OG - FG) x 131.25. For example, OG 1.055 and FG 1.012 gives (1.055 - 1.012) x 131.25 = 5.64% ABV. A more precise alternate formula used for high-gravity beers is ABV = (76.08 x (OG - FG) / (1.775 - OG)) x (FG / 0.794). Both are available in the calculator above. Q: What is apparent attenuation? A: Apparent attenuation (AA) measures how much of the fermentable sugars yeast has consumed, expressed as a percentage: AA = ((OG - FG) / (OG - 1)) x 100. A well-attenuating ale yeast typically achieves 73-80%. High attenuation means a drier, more fermented beer; lower attenuation leaves more residual sweetness and body. Q: How accurate is the OG/FG ABV formula? A: The standard formula is accurate to within 0.1-0.2% ABV for beers below about 8% ABV. Above that, the alternate Balling formula (available in the selector) is more reliable because alcohol and residual sugars interact non-linearly at high concentrations. Refractometer readings after fermentation also require a correction factor because alcohol changes the refractive index. Q: How many calories are in homebrew beer? A: Calories come from two sources: alcohol (7 kcal/g of ethanol) and residual fermentable sugars reflected in the final gravity. The calculator uses the Papazian / How to Brew formula: Cals/12 oz = 3.55 x (6.9 x ABV% + 4 x RE), where Real Extract (RE) is derived from original and final gravity converted to degrees Plato. A typical 5.6% pale ale (OG 1.055, FG 1.012) comes in at roughly 209 kcal per 355 ml serving, while a 10% imperial stout can exceed 370 kcal. Q: What is a normal FG for homebrew beer? A: Final gravity depends on yeast strain, mash temperature and recipe. Most ales finish between 1.008 and 1.015; lagers typically 1.006-1.012. Beers mashed high (68-70 C / 155-158 F) leave more unfermentable dextrins and finish higher. High-attenuating yeast strains can drop a 1.060 OG wort to 1.006 or lower. Q: Can I use a refractometer reading for FG? A: Not directly. After fermentation begins, alcohol lowers the refractive index, so a raw refractometer reading overstates the true gravity. Use the Sean Terrill correction: FG = 1.0000 - 0.0044993 x Brix_OG + 0.011774 x Brix_FG + 0.00027581 x Brix_OG^2 - 0.0012717 x Brix_FG^2 - 0.0000072800 x Brix_OG^3 + 0.0000063293 x Brix_FG^3. Alternatively, use a hydrometer for the final reading — it needs no correction. #### Beer IBU Calculator URL: https://geratools.com/beer-ibu-calculator Free beer IBU calculator using the Tinseth and Rager formulas. Add multiple hop additions, set alpha acids, boil times and batch size to get an accurate International Bitterness Units estimate. Runs entirely in your browser. How to use: 1. Set your original gravity and batch size: Enter the wort OG (e.g. 1.060) and your post-boil batch volume in litres. Higher gravity wort suppresses utilisation in the Tinseth model. 2. Choose Tinseth or Rager: Tinseth is the homebrewing community default: gravity-dependent, empirically fitted to real-world data. Rager uses a hyperbolic-tangent boil-time curve with a gravity adjustment above OG 1.050. 3. Add each hop addition: For every charge of hops enter the weight (g or oz), the alpha acid percentage from the packet label, and the time left in the boil when the hops go in. 4. Read the IBU total: Each row shows the utilisation percentage and IBU contribution. The running total appears at the bottom alongside matching beer styles. FAQ: Q: What is an IBU? A: IBU stands for International Bitterness Unit. One IBU equals one milligram of isomerised alpha acids per litre of beer. Human perception of bitterness varies but most people begin to taste it above about 8–10 IBU; an intensely bitter double IPA may reach 100 IBU or more. Q: What is the difference between Tinseth and Rager? A: Both are empirical curve-fits to measured isomerisation data. Tinseth (Glenn Tinseth, 1997) models utilisation as the product of a bigness factor (which falls as gravity rises) and a boil-time factor. Rager (Jackie Rager, 1990) uses a hyperbolic tangent for boil time and adds a separate gravity adjustment for worts above OG 1.050. Tinseth tends to give slightly lower numbers; Rager slightly higher. Neither is definitively correct — use the same formula consistently and calibrate against your own system. Q: Why does gravity affect IBU utilisation? A: In high-gravity wort, isomerised alpha acids bind to proteins and other compounds and drop out of solution more readily. The Tinseth bigness factor (1.65 x 0.000125^(OG - 1)) quantifies this suppression. At OG 1.040 utilisation is higher than at OG 1.080 for the same boil time. Q: Do late additions (e.g. dry hops or flameout) contribute IBUs? A: Dry hops added after fermentation contribute negligible IBUs because isomerisation requires sustained heat. Flameout or whirlpool additions at 0 minutes show near-zero IBUs in both Tinseth and Rager. In practice a hot whirlpool stand of 20–30 min at 80–90 C does isomerise some acids; to approximate this, enter 10–15 minutes in the boil-time field. Q: How accurate are these formulas? A: Both formulas have a typical error of plus or minus 10–20% compared with laboratory measurements because they do not account for wort pH, hop form (pellet vs. whole cone vs. extract), boil vigour, kettle geometry, or trub losses. Pellet hops typically yield 10–15% more IBUs than whole cone for the same weight and alpha acid content. Treat the result as a well-calibrated estimate, not a laboratory measurement. Q: What IBU range should I target for common styles? A: Light lagers sit at 8–12 IBU; wheat beers 8–15; pale ales 30–50; IPAs 40–70; double IPAs 60–120; stouts and porters 25–45; barleywines 50–100. The calculator highlights matching styles automatically. Bear in mind that perceived bitterness also depends on residual sweetness (final gravity) — the same IBU will taste sharper in a dry beer than in a malty one. #### Meat Curing Calculator URL: https://geratools.com/meat-curing-calculator Free meat curing calculator. Enter your meat weight and choose Prague Powder #1, #2 or Morton Tender Quick to get exact gram quantities of curing salt, salt and sugar for equilibrium dry cures or wet brines — plus a minimum curing time and estimated nitrite level. 100% browser-based. How to use: 1. Enter your meat weight: Type the weight of your trimmed piece of meat and choose the unit (grams, kg, lb or oz). The calculator converts everything to grams internally so all ratios stay correct. 2. Select your curing salt: Choose Prague Powder Number 1 for short-cured or cooked products such as bacon, ham and pastrami. Choose Prague Powder Number 2 for long dry-cured whole muscles such as bresaola, pancetta and guanciale that hang for more than 30 days. Choose Morton Tender Quick if you prefer an all-in-one cure blend that replaces the separate salt addition. 3. Choose dry or wet cure: Dry cure applies the rub directly to the meat surface and the cure equilibrates over time. Wet cure (brine) dissolves everything in water first; enter the water weight so that the salt and sugar percentages are calculated against total weight (meat plus water) for correct equilibration. 4. Adjust salt and sugar percentages: The defaults (2.5% salt, 0.5% sugar for PP Number 1) are standard starting points. Increase salt to 3% for a firmer, saltier result or drop to 2% for a milder cure. Sugar aids browning and slightly offsets saltiness; brown sugar or maple syrup (weighed) works equally well. 5. Enter the thickest point in millimetres: The minimum curing time guide uses the thickest part of the muscle. For a dry cure a common rule is roughly 0.4 days per millimetre for PP Number 1 products; PP Number 2 products need around 1 day per millimetre plus extended hang time. 6. Read your recipe and copy it: The results panel shows every ingredient in grams, the estimated nitrite level in parts per million and the minimum cure time. Hit Copy Recipe to paste the full recipe into your notes or a kitchen label. FAQ: Q: What is the equilibrium curing method? A: Equilibrium (EQ) curing means you apply exactly the amount of salt and cure needed to reach the desired final concentration in the meat — no more, no less. Unlike traditional excess-salt curing, EQ curing produces a consistently seasoned result regardless of how long you leave the meat in the fridge (within reason). You simply weigh out a fixed percentage of salt and curing salt relative to the meat weight, rub it in, vacuum-seal or wrap tightly, and refrigerate. The salt migrates into the muscle until equilibrium is reached. Q: How much Prague Powder Number 1 do I use per kg of meat? A: The standard dose for Prague Powder Number 1 is 0.25% of the meat weight, which equals 2.5 grams per kilogram. This delivers approximately 156 ppm of nitrite — the upper limit recognised as safe and effective by the USDA. Never exceed this dose; curing salt is not a seasoning and too much nitrite is harmful. Q: What is the difference between Prague Powder 1 and Prague Powder 2? A: Prague Powder Number 1 contains 6.25% sodium nitrite mixed with salt and is used for products that will be cooked or eaten within 30 days — bacon, corned beef, pastrami, ham and hot-smoked fish. Prague Powder Number 2 additionally contains 4% sodium nitrate, which converts slowly to nitrite over weeks and months, making it suitable for long-aged, uncooked charcuterie such as bresaola, coppa, guanciale and prosciutto. Never substitute one for the other. Q: Can I use table salt instead of kosher salt when curing? A: You can, but weight-based measuring is essential because table salt is denser than kosher or sea salt — the same volume contains significantly more sodium. This calculator works by weight (grams), so as long as you weigh your salt accurately the type does not matter for the outcome. Kosher and flaky sea salts are preferred by most curers because they are easy to see on the meat surface and dissolve evenly. Q: How long should I cure bacon using this calculator? A: A typical pork belly for bacon is 30–50 mm thick at its thickest point. At the standard 0.4 days-per-millimetre guideline that gives a minimum of 12–20 days for equilibrium to be reached. Many curers leave a pork belly for 7–10 days in practice because the EQ method is forgiving — you cannot over-salt as you would with an excess-salt cure. Once cured, cold-smoke (if desired) and cook to an internal temperature of 71 °C before eating. Q: Is 156 ppm nitrite safe? A: Yes. The USDA limits sodium nitrite in cured meat products to 156 ppm (156 mg per kg of meat). The standard dose of 0.25% Prague Powder Number 1 — which contains 6.25% nitrite — delivers almost exactly this level. Nitrite is what prevents botulism and other dangerous bacteria in anaerobic (low-oxygen) curing environments; it also gives cured meat its characteristic pink colour and flavour. Using less than the recommended dose risks under- protection; using more than the recommended dose provides no extra safety and raises health concerns. #### Wine Bottles Per Guest Calculator URL: https://geratools.com/wine-bottles-per-guest-calculator Free wine bottles per guest calculator. Enter your guest count, event duration and consumption rate to get total bottles, red/white/sparkling split, cases needed and optional cost estimate. 100% client-side — nothing uploaded. How to use: 1. Choose your event type: Pick a preset such as wedding reception or dinner party, or select Custom to enter your own figures. 2. Enter guests and duration: Type the number of people attending and how many hours the event will last. 3. Set the consumption rate: Choose glasses per guest per hour — 1 is moderate, 1.5 suits a relaxed social gathering, 2 is generous. 4. Adjust the wine split: Set the percentage of red, white and sparkling wine. The sparkling percentage fills automatically so the three values always total 100%. 5. Add a safety buffer and price: Slide the buffer up to add extra bottles as insurance, then enter a price per bottle for a total cost estimate. FAQ: Q: How many bottles of wine do I need per person? A: A common catering rule is one bottle per two guests for a two-hour meal (roughly half a bottle or 2.5 glasses each). For a longer reception of four or more hours, plan for one bottle per guest. This calculator lets you dial in the exact duration and drinking pace so the figure is tailored to your event rather than a rough guess. Q: How is the bottle count calculated? A: The formula is: Total glasses = guests × hours × glasses-per-hour. That figure is multiplied by your safety buffer (default 10%), then divided by 5 — because a standard 750 ml bottle yields five 150 ml pours. The result is rounded up so you always have a whole bottle rather than a partial one. Q: What is a standard wine pour at an event? A: The industry standard for catered events and restaurants is 150 ml (5 fl oz) per pour. A 750 ml bottle therefore yields exactly 5 glasses. At a self-serve party guests may pour more generously, which is why the consumption-rate slider and safety buffer exist. Q: What is the recommended red, white and sparkling split? A: A typical UK wedding uses roughly 50% red, 30% white and 20% sparkling. A summer garden party skews toward white and sparkling; a winter dinner skews toward red. The calculator defaults to a wedding-style split but you can adjust it freely — sparkling recalculates automatically so the total always stays at 100%. Q: Should I add a safety buffer? A: Yes. Running out of wine mid-event is far worse than having a few bottles left over (which can be returned to most retailers if unopened). A 10% buffer adds roughly one extra bottle per case and is the minimum recommended for any hosted event; push it to 20% for large weddings or events where resupply is impractical. Q: How many bottles are in a case of wine? A: A standard case holds 12 bottles of 750 ml wine, totalling 9 litres. Buying by the case is almost always cheaper per bottle and easier to transport. The calculator shows the number of full cases plus any loose bottles left over so you can plan your order precisely. ### Farming & Garden #### Aquaculture Stocking Density Calculator URL: https://geratools.com/aquaculture-stocking-density-calculator Computes how many fingerlings to stock, the maximum carrying biomass, and daily feed loading for a pond or tank from its volume, a species-specific maximum density in kg per cubic metre, target harvest weight, and feeding rate. Flags whether aeration is needed. A pond and tank planning aid for aquaculture managers. How to use: 1. Enter the water volume: Type the pond or tank volume in cubic metres, or enter surface area and depth to have it computed. 2. Set species and weights: Enter the maximum safe density in kg per cubic metre for your species and system, the target harvest weight per fish, and the stocking weight of fingerlings. 3. Read stocking and feed: The tool gives the maximum harvest biomass, the number of fingerlings to stock, and the daily feed required at your feeding-rate percentage. FAQ: Q: How is the number of fingerlings to stock found? A: Maximum biomass equals the volume multiplied by the maximum density in kilograms per cubic metre. Dividing that biomass by the target harvest weight per fish gives the number of fish the system can carry at harvest, which is the number to stock allowing for survival. Q: What is a typical maximum density? A: It depends heavily on the species and aeration. Static earthen ponds often hold 1 to 5 kg per cubic metre, aerated ponds 5 to 20, intensive tilapia tanks 20 to 40, and recirculating catfish systems 40 to 100 or more with strong aeration and water exchange. Use the figure your system can actually support. Q: How is daily feed loading calculated? A: Daily feed equals the current biomass multiplied by the feeding rate, which is a percentage of body weight per day. Fingerlings are fed at 5 to 10 percent of body weight, growers at 2 to 4 percent, and fish near harvest at 1 to 2 percent, decreasing as they grow. Q: Why does aeration matter for density? A: Fish consume oxygen, and at high biomass the natural oxygen supply of the water is exceeded, causing stress, slow growth, or kills. Aeration raises the safe carrying capacity. The tool flags when your chosen density is in the range that normally requires mechanical aeration. Q: Should I account for expected mortality? A: Yes. Stock slightly more fingerlings than the carrying number so that, after expected losses, the surviving fish reach the target biomass. Enter a survival percentage and the tool scales the stocking number up accordingly. #### Aquarium Flow & Turnover Rate Calculator URL: https://geratools.com/aquarium-flow-turnover-calculator Enter tank volume and desired turnover rate (times per hour) to find the minimum filter or powerhead flow in GPH and LPH. Shows recommended turnover by tank type — reef, fish-only, planted, cichlid. For aquarium keepers. How to use: 1. Enter tank volume: Type the tank water volume in litres or gallons. 2. Choose a turnover rate: Pick a tank type to load a recommended turnover, or enter your own turnover in times per hour. 3. Read the required flow: The tool shows the minimum combined flow rate your filters and powerheads must deliver, in both GPH and LPH. FAQ: Q: What does turnover rate mean? A: Turnover is how many times the entire tank volume passes through circulation each hour. A turnover of 10x on a 200 litre tank means 2000 litres of water move per hour. It is the standard way to express how vigorously a tank is circulated, independent of tank size. Q: How much turnover does each tank type need? A: Rough targets are 4 to 6x for planted tanks, 5 to 10x for fish-only and cichlid tanks, and 20 to 40x for reef tanks where corals need strong, varied flow. Reef figures usually combine a return pump with several powerheads or wavemakers rather than one giant pump. Q: Should I use my filter's rated flow as-is? A: No. Manufacturer ratings are measured with an empty filter and no head height. Media, hoses, and lifting water above the tank cut real flow by 25 to 40 percent. Buy a pump rated meaningfully above your target so the in-tank flow still meets the number this tool gives. Q: Can a tank have too much flow? A: Yes. Excessive flow stresses slow-swimming fish like bettas and fancy goldfish, blows substrate around in planted tanks, and prevents food from settling. Match flow to the livestock: high for reef SPS corals and rheophilic fish, gentle for labyrinth fish and shrimp. Q: Does the calculator account for head height? A: The base result is the required in-tank flow. Because real pumps lose flow to head height and media, the tool also shows a suggested purchase rating about 35 percent higher so the delivered flow still meets your target after those losses. #### Aquarium Live Rock Amount Calculator URL: https://geratools.com/aquarium-live-rock-amount-calculator Enter your reef tank volume and choose a rock type — porous premium, standard live rock, or dense dry ceramic — to get the recommended pounds of rock, a low-to-high range, and an estimated cost using your own price per pound. How to use: 1. Enter tank volume: Type your display tank volume in gallons or litres so the tool can apply the standard rock-per-volume guideline. 2. Pick the rock type: Choose porous premium, standard, or dense ceramic rock — denser rock weighs more per unit of structure, lowering the pounds you need. 3. Read the amount and cost: The tool shows a recommended weight, a low-to-high range, and a cost estimate from your own price per pound. FAQ: Q: How much live rock do I need per gallon? A: The long-standing guideline is roughly 1 to 1.5 pounds of live rock per gallon of tank volume, with the lower end for porous, lightweight rock and the higher end for denser rock. This tool applies that range and adjusts it for rock density. Q: Why does rock type change the amount? A: Live rock works by surface area and structure, not raw weight. Dense ceramic or dry rock packs more mass into the same shape, so you need fewer pounds to build the same aquascape, while light porous rock needs more pounds for equivalent structure. Q: Should I count my sump or just the display? A: Base the calculation on the display tank you are aquascaping. Many reefers actually run less rock in the display for flow and use additional biomedia in the sump, so treat the result as an upper guide rather than a strict minimum. Q: Is more live rock always better? A: No. Modern reefkeeping trends toward less rock for better water flow and open aquascapes, relying on the rock surface plus sump filtration for biological capacity. Use the range as a guide and lean lighter if you want open scaping and strong circulation. Q: How do I estimate the cost? A: Enter your local price per pound for the rock type you are buying and the tool multiplies it by the recommended weight. Cured live rock costs more than dry rock, which you cure yourself over weeks, so price the specific product you intend to use. #### Aquarium Salinity / Specific Gravity Converter URL: https://geratools.com/aquarium-salinity-converter Convert aquarium salinity between parts per thousand (ppt/PSU), specific gravity at a chosen temperature, and conductivity. Uses seawater density relations with hydrometer temperature correction for marine and reef aquarists. How to use: 1. Pick what you measured: Choose whether you are entering salinity in ppt, specific gravity, or conductivity, and type the value. 2. Set the temperature: Enter the temperature at which you took the reading so the specific gravity is corrected to the standard reference. 3. Read the converted values: The tool shows the equivalent salinity, specific gravity (referenced to 25C over 25C), and conductivity, with a target band for reef tanks. FAQ: Q: Why does specific gravity depend on temperature? A: Water density falls as it warms, so the same salt content reads as a lower specific gravity in warmer water. A reading must be tied to a reference temperature to be meaningful. This converter standardises to specific gravity at 25C referenced to pure water at 25C, the convention most reef hydrometers use. Q: What salinity should a reef tank be? A: Natural seawater is about 35 ppt, which is roughly 1.0264 specific gravity at 25C or about 53 mS/cm conductivity. Most reef keepers target 34 to 36 ppt. Fish-only marine tanks tolerate a slightly wider range, around 30 to 35 ppt. Q: How accurate are swing-arm hydrometers? A: Plastic swing-arm hydrometers are convenient but drift and trap bubbles, often reading several points off. A calibrated refractometer or a conductivity probe is far more reliable. Use this converter to cross-check whichever instrument you own. Q: What is the difference between ppt and PSU? A: Parts per thousand (ppt) is a mass fraction of dissolved salts, while the practical salinity unit (PSU) is defined from conductivity ratios. Near typical seawater values the two are numerically almost identical, so this tool treats them as interchangeable for aquarium use. Q: Does conductivity change with temperature too? A: Yes, conductivity rises with temperature, but most aquarium conductivity meters report a temperature-compensated value referenced to 25C. The conductivity figure here is that 25C-referenced value, so read your meter in its compensated mode. #### Drip Irrigation Run Time Calculator URL: https://geratools.com/garden-watering-schedule-calculator Enter your drip emitter flow rate in GPH or LPH, the number of emitters, and the total water volume you want to deliver to compute the exact run time in minutes, plus the system flow rate and per-emitter delivery. How to use: 1. Enter emitter flow: Type the rated flow of a single emitter in gallons per hour or litres per hour, printed on the emitter or its packaging. 2. Add emitter count and target: Enter how many emitters are on the zone and the total volume of water you want to deliver to the bed in this run. 3. Read the run time: The tool returns the run time in minutes to reach your target, along with total system flow and how much each emitter delivers. FAQ: Q: How long should I run my drip irrigation? A: Run time depends on emitter flow and how much water you want delivered, not a fixed clock. Decide a target volume for the bed, then this tool divides it by your system's total flow rate to give the exact minutes to run. Q: How is the run time calculated? A: Total system flow is the single emitter rate multiplied by the number of emitters. Run time in minutes is your target volume divided by that flow, scaled to minutes. For example, 10 emitters at 1 GPH deliver 10 gallons per hour, so 5 gallons takes 30 minutes. Q: Should target volume be per plant or per zone? A: Enter the total for the whole zone you are scheduling. If you know a per-plant need, multiply by the number of plants first. The tool also reports per-emitter delivery so you can check each plant gets a sensible amount. Q: Do emitter ratings stay accurate? A: Pressure-compensating emitters hold close to their rated flow across a range of pressures, while non-compensating emitters vary with pressure and line length. If your emitters are not pressure-compensating, treat the result as an estimate and verify with a catch-cup test. Q: Can I mix GPH and LPH? A: Pick one unit system and stay in it. Choose gallons or litres at the top, and enter both the emitter rate and the target volume in that same unit so the run time stays correct. Q: Is it better to water a little every day or deeply a few times a week? A: For established plants, deep and infrequent wins — the same weekly volume delivered in 2–3 longer soaks encourages deeper roots and drought resilience, while daily sips keep roots shallow. The exceptions are seedlings and transplants, which need light frequent watering until established, and very sandy soil, which can't hold a large soak and needs smaller, more frequent runs. #### Grain Storage Capacity Calculator URL: https://geratools.com/grain-storage-capacity-calculator Compute grain capacity in bushels or metric tonnes for round bins, rectangular flat stores, and conical piles from dimensions and test weight. Built for grain producers and elevator managers for inventory and insurance. Runs in your browser. How to use: 1. Choose the storage type: Select a round bin, a rectangular flat store, or a conical pile and enter the dimensions in feet. 2. Pick the grain and units: Choose the grain so the right test weight is used, or enter your own, and pick whether you want bushels or metric tonnes. 3. Read the capacity: The tool calculates the volume in cubic feet, converts to bushels using the 1.2445 factor, and to tonnes using the grain test weight. FAQ: Q: How are cubic feet converted to bushels? A: One US bushel of dry shelled grain occupies about 1.2445 cubic feet, so bushels equal cubic feet divided by 1.2445, or cubic feet times 0.8036. This is a volume bushel and is the standard used for bin capacity, independent of the grain type. Q: What is test weight and why does it set the tonnage? A: Test weight is the weight of grain that fills a one-bushel measure, such as 56 lb for corn or 60 lb for wheat and soybeans. Multiplying bushels by test weight gives pounds, which convert to tonnes. Denser, drier grain weighs more per volume bushel. Q: How is a round bin volume calculated? A: The cylinder volume is pi times the radius squared times the grain depth. If you fill above the eave into the cone of a peaked roof, add the cone, one-third times pi times radius squared times peak height. This tool covers the cylindrical section and an optional peak. Q: How do I estimate a free-standing grain pile? A: A symmetrical conical pile is one-third times pi times the base radius squared times the peak height. The peak height depends on the grain's angle of repose, roughly 23 degrees for corn and wheat, which the tool can estimate from the base diameter if you do not measure it. Q: Does this account for packing or moisture? A: The volume-to-bushel conversion already reflects typical packing of free-flowing grain. It does not adjust for moisture shrink or for very fine or trashy grain that packs tighter. For weight, use the actual test weight of your grain at its current moisture. #### Harvest Moisture Loss & Shrink Calculator URL: https://geratools.com/harvest-moisture-loss-calculator Applies the wet-to-dry conversion formula to turn field-moisture weight into standard-moisture bushels, computes the moisture-shrink dollars at the elevator discount schedule, and shows break-even drying cost for sell-or-dry decisions at harvest. How to use: 1. Enter your field weight and moisture: Type the wet weight in pounds from the scale ticket and the field moisture percentage from the moisture meter. 2. Set the standard moisture and shrink: Enter the standard moisture for your crop, the handling shrink percentage, and your test weight per bushel. 3. Read net bushels and the discount: The tool shows water removed, net standard-moisture bushels, the elevator moisture discount in dollars, and your net payment. FAQ: Q: What is the difference between water-removal and handling shrink? A: Water-removal shrink is the real weight you lose when drying grain down to the standard moisture, because the water physically leaves. Handling or invisible shrink is an extra percentage the elevator charges for dust, fines, and dry-matter loss during the drying process. Q: How is wet weight converted to standard-moisture bushels? A: The dry weight equals wet weight times (100 minus field moisture) divided by (100 minus standard moisture). Dividing that net weight by the test weight per bushel gives standard-moisture bushels. This is the same formula elevators use on settlement tickets. Q: What is a typical standard moisture? A: Corn is usually traded at 15 percent and soybeans at 13 percent in the US, though contracts vary. Wheat standards differ by class. Always use the standard stated in your delivery contract because the discount is calculated against it. Q: Should I dry my own grain or take the elevator discount? A: Compare your on-farm drying cost per bushel against the moisture discount the elevator charges. If drying costs less per point removed than the elevator docks, drying yourself nets more money. The tool shows the break-even drying cost to make this call. Q: Does the calculation account for test weight? A: Yes. Bushels are weight divided by the test weight per bushel, so a low test weight produces fewer bushels from the same pounds. Enter the actual test weight from your sample, not the nominal 56 or 60 pounds, for an accurate bushel count. #### Hay Bale Weight Estimator URL: https://geratools.com/hay-bale-weight-estimator Estimate the weight of round, small square, and large square hay bales from their dimensions and forage type using bale-volume math and species density factors. Helps hay buyers, livestock producers, and haulers gauge loads without a scale. How to use: 1. Choose bale type and forage: Select round, small square, or large square, then pick alfalfa, grass, or a legume-grass mix to set the density factor. 2. Enter the dimensions: Type the bale measurements in feet (diameter and width for round bales, or length, width, and height for square bales). 3. Read the estimated weight: The tool computes bale volume, multiplies by the forage density, and shows the estimated weight in pounds and kilograms. FAQ: Q: How is hay bale weight estimated from dimensions? A: Weight equals bale volume times the hay's bulk density. A round bale's volume is pi times radius squared times width; a square bale's volume is length times width times height. Multiplying cubic feet by pounds per cubic foot gives the estimated weight. Q: What density should I use for different hay types? A: Density depends on species and how tightly the bale was packed. Dry alfalfa runs roughly 11 to 14 lb per cubic foot, grass hay around 8 to 11, and legume-grass mixes in between. Tighter-wrapped and finer-stemmed hay packs denser, raising the weight. Q: Why do two same-size bales weigh differently? A: Bale density varies with moisture, baler pressure, forage maturity, and leaf content. A wet or tightly wrapped bale weighs more than a loose, dry one of identical size. Treat the estimate as a planning figure and verify critical loads on a scale. Q: Does moisture content affect the estimate? A: Yes. Wetter hay is heavier per cubic foot but also riskier to store. These density factors assume baling-dry hay around 12 to 18 percent moisture. Freshly baled high-moisture hay will weigh more than the estimate and should be checked before stacking. Q: How do I avoid overloading a trailer? A: Estimate one bale's weight, multiply by the number of bales, and compare to your trailer and truck rating with a safety margin. Because density varies, weigh a representative bale on a scale when you can, and round your count down rather than up. Q: Why is a 5-foot round bale so much heavier than a 4-foot one? A: Because weight scales with diameter squared. Going from a 4-ft to a 5-ft diameter at the same width adds roughly 56% to the weight, not 25%. This is why loader and trailer capacity that suits 4×4 bales can be badly under-spec for 5×5 bales. Q: Does more of a round bale's weight sit in the outer layers? A: Yes. Because volume grows with the radius squared, the outer foot of a 5-ft round bale holds about two-thirds of its total volume. Weathering or spoilage on the outside therefore removes far more feed and weight than the thin outer rind appears to represent. #### Herbicide / Pesticide Tank Mix Calculator URL: https://geratools.com/herbicide-mix-calculator Enter the label rate per acre, spray volume (GPA), tank size, and field area to get product per tank, tank fills needed, and total product to order. Built for spray operators and agronomists to fill sprayers accurately. Runs in your browser. How to use: 1. Enter the label rate and spray volume: Type the labeled product rate per acre and your carrier spray volume in gallons per acre (GPA) from the product label. 2. Enter tank and field size: Type your sprayer tank capacity in gallons and the total acres you intend to treat. 3. Read the mixing plan: The tool shows acres per tank, product to add per tank, number of full tanks plus the partial, and total product to order. FAQ: Q: How does the tool decide how much product goes in each tank? A: It first finds how many acres one tank covers by dividing tank size by your spray volume per acre. It then multiplies that acreage by the label rate to get the product per tank. A 300 gal tank at 15 GPA covers 20 acres, so at 32 oz/acre you add 640 oz. Q: What is spray volume or GPA? A: Gallons per acre (GPA) is the total carrier volume, mostly water, your sprayer applies to each acre. It is set by your nozzles, pressure, and travel speed, and the product label usually specifies a recommended range such as 10 to 20 GPA. Q: Does it handle a partial last tank? A: Yes. Most fields do not divide evenly into full tanks. The tool reports the whole number of full tanks plus the acres and product for the final partial tank, so you do not overmix and waste chemical. Q: Should I add product before or after filling with water? A: Follow the label, but the general order is fill the tank one-half to two-thirds with water, start agitation, add products in WALES order (wettable powders, agitate, liquids, emulsifiables, surfactants), then top off. This tool gives the quantities, not the sequence. Q: Can I use it for ounces, fluid ounces, pints, or quarts? A: Yes. The rate units are whatever you enter, so if your label rate is in fl oz/acre the product per tank and total are also in fl oz. Keep the rate and your measuring units consistent. #### All-Grain to Extract Conversion Calculator URL: https://geratools.com/malt-extract-conversion Convert base malt from an all-grain recipe into the equivalent dry malt extract or liquid malt extract, using standard extract potential and your mash efficiency. Lets extract brewers follow all-grain recipes and hit the same gravity. Runs entirely in your browser. How to use: 1. Enter the base malt weight: Add up the base malt (pale, 2-row, Pilsner, Maris Otter) in the all-grain recipe and enter the total weight. Specialty and crystal malts are handled separately by steeping. 2. Set your all-grain efficiency: Enter the mash efficiency the original recipe assumes, usually around 75 percent. This determines how many gravity points the grain would actually have yielded. 3. Read the extract equivalents: The calculator shows the weight of dry malt extract or liquid malt extract that delivers the same gravity, so you can swap one in for the base malt. FAQ: Q: How does the conversion work? A: Base malt yields about 37 gravity points per pound per gallon at full conversion, but you only capture a fraction set by your efficiency. Dry and liquid malt extracts are pre-converted, so they deliver close to their full rated potential. The tool scales the base malt down to the extract weight that matches the same effective gravity points. Q: Should I convert specialty and crystal malts too? A: No. Only base and extract-style malts are converted by this tool. Crystal, caramel, roasted, and other specialty grains contribute colour and flavour and are added by steeping at their original recipe weights. Convert just the base malt to extract and steep the rest as usual. Q: What is the difference between DME and LME? A: Dry malt extract is dehydrated and more concentrated, yielding about 44 points per pound per gallon. Liquid malt extract still contains roughly 20 percent water, so it yields about 36 points per pound and you need more of it for the same gravity. The calculator shows both so you can pick whichever you have. Q: Why does efficiency matter for the conversion? A: All-grain brewers only extract part of the sugar locked in malt, set by their mash efficiency. A recipe written for 75 percent efficiency assumes that much of the grain potential reaches the kettle. Extract is already converted, so the conversion must scale by efficiency to land on the same original gravity. Q: When in the boil do I add the extract? A: A common approach is late extract addition, where you add part of the extract at the start and the rest near the end of the boil. This reduces darkening and caramelisation and gives lighter, fresher results. The total weight is what this calculator gives you; how you split it across the boil is up to you. #### Nitrogen Use Efficiency (NUE) Calculator URL: https://geratools.com/nitrogen-use-efficiency-calculator Computes Nitrogen Use Efficiency by dividing total crop nitrogen uptake (yield × grain N content) by total nitrogen supplied (fertilizer + organic + atmospheric deposition), expressed as a percentage, then benchmarks against typical crop values to flag over-application. A field-budgeting aid for agronomists and precision-ag consultants. How to use: 1. Enter yield and N content: Type the harvested yield and the nitrogen content of the harvested portion (grain or biomass) as a percentage of dry matter. 2. Enter nitrogen supplied: Add the nitrogen applied as fertilizer, plus any organic manure nitrogen and estimated atmospheric deposition for your region. 3. Read the NUE: The tool divides crop uptake by nitrogen supplied to give NUE percent and compares it to typical ranges so you can see whether you are over-applying. FAQ: Q: How is nitrogen uptake calculated from yield? A: Crop nitrogen uptake equals harvested dry-matter yield multiplied by the nitrogen concentration of that harvested material. For example, 8 tonnes of wheat grain at 2 percent nitrogen removes 160 kg of nitrogen per hectare in the grain. Q: What counts as nitrogen supplied? A: Total nitrogen supplied includes mineral fertilizer nitrogen, the plant-available nitrogen in any manure or organic amendment applied, and atmospheric deposition. Some definitions also include residual soil mineral nitrogen; this tool lets you add an organic and deposition figure. Q: What is a good NUE value? A: Recovery-based NUE for cereals commonly sits between 40 and 65 percent in well-managed systems. A value below about 40 percent suggests losses through leaching, volatilization, or denitrification and an opportunity to cut rates or split applications. Values near or above 100 percent indicate the crop is mining soil nitrogen. Q: Why can NUE exceed 100 percent? A: If the crop removes more nitrogen than you applied, it is drawing on soil organic-matter mineralization or residual nitrogen. That is unsustainable over time and signals that the soil nitrogen bank is being depleted and needs replenishing. Q: Should I keep units consistent? A: Yes. Keep yield and all nitrogen figures in the same area basis, for example per hectare or per acre, and the same mass unit. The tool works on whatever consistent units you enter because NUE is a ratio. #### Silage Tonnage Calculator URL: https://geratools.com/silage-tonnage-calculator Calculate silage volume for bunker, wedge, or round-pile geometry, then apply a bulk density to estimate fresh-weight and dry-matter tonnes at a given moisture. Helps farm managers inventory feed before winter. Runs in your browser. How to use: 1. Choose the storage shape: Select a rectangular bunker, a wedge-shaped clamp, or a round pile and enter the relevant dimensions in metres. 2. Enter density and moisture: Type the silage as-fed bulk density in kg per cubic metre and the moisture content percentage from a sample. 3. Read fresh and dry-matter tonnes: The tool computes the volume, multiplies by density for fresh-weight tonnes, then applies the dry-matter percent to estimate the dry-matter tonnes available. FAQ: Q: How is the volume worked out for each shape? A: A bunker is length times width times average settled height. A wedge clamp uses the average of its tall and short ends as the mean height. A round pile is treated as a cone, one-third times the base area times height. All are in cubic metres before applying density. Q: What bulk density should I use? A: Well-consolidated grass and maize silage in a bunker typically runs 650 to 800 kg per cubic metre as fed, higher with good packing and lower for loose or dry crops. A poorly packed pile can be 500 kg or less. Use a measured figure where possible because density drives the result. Q: Why does moisture matter for an inventory? A: Animals are fed on a dry-matter basis, so wet silage weighs more but feeds less per tonne. Converting fresh tonnes to dry-matter tonnes, by multiplying by one minus the moisture fraction, tells you how much actual feed value is in the clamp. Q: Is the calculated tonnage the amount I can feed? A: Not entirely. There are always losses from surface spoilage, shoulders, and feed-out face management, commonly 5 to 15 percent. Treat the figure as gross inventory and discount for expected waste when planning how many days it will last. Q: Can I use imperial units? A: Enter dimensions in metres and density in kg per cubic metre for this tool. To convert, one foot is 0.3048 m and 1 lb per cubic foot is about 16.02 kg per cubic metre. The output tonnes are metric (1000 kg). #### Tank-Mix Partner Compatibility Reference URL: https://geratools.com/tank-mix-partner-compatibility-tool Pick two agrochemical active ingredients and see a general compatibility flag plus notes on antagonism, precipitation, and adjuvant needs from an embedded reference. A planning aid for crop advisors before mixing multi-product loads. Runs in your browser. How to use: 1. Select the first active ingredient: Choose the primary product or active ingredient you plan to apply from the dropdown list. 2. Select the partner: Choose the second active ingredient or adjuvant you want to add to the same tank load. 3. Read the compatibility flag and notes: The tool shows a green, amber, or red flag with a short explanation of any antagonism, precipitation risk, or adjuvant requirement to consider. FAQ: Q: Is this a substitute for the product label and a jar test? A: No. This is a general planning reference based on widely published agronomic guidance. The product label is the legally binding source, and a small jar test of your actual products and water is the only way to confirm a specific physical mix is stable. Q: Why does glyphosate show antagonism with some products? A: Glyphosate can be antagonised when tank-mixed with certain contact and ALS herbicides, and hard water cations such as calcium and magnesium can bind it. Ammonium sulfate is often added to condition water and reduce that antagonism. The reference flags these cases. Q: What does an amber flag mean? A: Amber means the combination is commonly used but carries a caveat, such as a required water conditioner, a specific mixing order, reduced efficacy on certain weeds, or a crop-stage restriction. Read the note and verify against the labels before mixing. Q: Does compatibility depend on water quality and temperature? A: Yes. Hard or alkaline water, very cold water, and high product concentration all increase the chance of antagonism or precipitation. The reference notes water conditioning where it matters, but you should still match conditions to your actual situation. Q: What mixing order reduces problems? A: A common order is water conditioners and AMS first, then dry formulations (WDG/WP), then suspensions, then emulsifiable concentrates, then surfactants and oils last, with full agitation throughout. Always follow any order specified on the labels of the products you are using. #### Hydroponic Nutrient Calculator URL: https://geratools.com/hydroponic-nutrient-calculator Free hydroponic nutrient calculator. Enter your reservoir size and EC target to get precise gram weights for calcium nitrate, potassium nitrate, KH2PO4, Epsom salt, iron EDTA and all micronutrients. Based on Modified Hoagland solution. Runs entirely in your browser. How to use: 1. Choose a crop profile: Pick General Purpose, Leafy Greens, Fruiting or Seedling to load the appropriate elemental targets. 2. Enter your reservoir volume: Type the volume in litres. The tool scales all salt weights linearly. 3. Set your EC target: Dial in your desired electrical conductivity in mS/cm. The default 2.0 mS/cm matches full-strength Hoagland solution. 4. Adjust strength scale if needed: Use the strength percentage slider to halve or double the recipe without changing the EC reference. 5. Read off the macro salt weights: The table shows grams of each salt to dissolve in your reservoir. Click Show micronutrient salts for the trace element doses. 6. Copy and mix: Hit Copy full recipe to paste the complete recipe into your grow journal or notes app. FAQ: Q: What formula does the calculator use? A: For every fertiliser salt the mass in grams is: mass_g = (target_ppm × volume_L × MW_salt) / (n × AW_element × 1000), where target_ppm is mg of element per litre, MW_salt is the molar mass of the compound, n is the stoichiometric count of that element per formula unit, and AW_element is the atomic weight. Dividing by 1000 converts mg to g. Q: What is the Modified Hoagland solution? A: The Hoagland and Arnon (1950) nutrient solution is the most widely cited general-purpose hydroponic formula in the scientific literature. It defines elemental concentrations for all 13 essential mineral nutrients. Most commercial hydroponic base nutrients target very similar ratios. This calculator uses the commonly updated "Modified Hoagland" values that slightly reduce nitrogen and boost iron chelation for modern growing systems. Q: What does EC measure in hydroponics? A: Electrical conductivity (EC), measured in mS/cm or mS per centimetre, reflects the total dissolved ion concentration in your nutrient solution. A higher EC means more nutrient ions in solution. Most crops grow best between 1.2 and 3.5 mS/cm. Seedlings prefer 0.5-1.2 mS/cm, leafy greens thrive at 1.6-2.2 mS/cm, and fruiting crops like tomatoes do well at 2.0-3.5 mS/cm. Q: Why are macro salts split across multiple compounds? A: No single compound supplies nitrogen, phosphorus, potassium, calcium, magnesium and sulphur in the proportions plants need. Calcium and phosphate also precipitate if dissolved together at high concentration, which is why calcium nitrate is always kept in a separate stock solution (Part A) from the phosphate and sulphate salts (Part B). The calculator allocates each element to its most practical carrier salt. Q: Can I use this for DWC, NFT, ebb-and-flow and coco coir? A: Yes. The calculator outputs elemental mg/L targets that apply regardless of growing system. DWC, nutrient film technique, ebb-and-flow, and coco coir all use the same dissolved salt approach. Coco coir growers sometimes boost calcium and magnesium by 10-15% because coco has a natural cation-exchange capacity that binds Ca and Mg. Use the strength scale input to compensate. Q: How do I adjust the recipe for hard tap water? A: Hard tap water already contains calcium, magnesium and sulphate, so adding full doses of calcium nitrate and Epsom salt can push those elements well above target. Run your tap water through a TDS/EC meter first. As a rule of thumb, reduce the calcium nitrate dose by roughly 1 g per 100 L for every 50 ppm of calcium already present in your source water. Q: Is it safe to store the results on this page? A: The calculator saves your reservoir volume, EC target and crop profile in your browser's localStorage so the values are still there when you come back. Nothing is sent to a server. The data never leaves your device. #### Chicken Feed Calculator URL: https://geratools.com/chicken-feed-calculator Free chicken feed calculator. Enter flock size, bird type, body weight, and temperature to get daily feed intake, water needs, ME and CP requirements, nutrient adequacy checks, egg economics, and annual feed costs. 100% browser-based — nothing uploaded. How to use: 1. Select your chicken type: Choose from commercial layers, free-range layers, broiler starters, growers or finishers, pullets, chick starters, or breeder hens. Each type loads the correct NRC nutrient requirements automatically. 2. Enter flock size and body weight: Type the number of birds and the average body weight in kg per bird. For layers, also set the laying rate (%) and average egg weight in grams. 3. Set ambient housing temperature: Temperature affects both metabolisable energy (ME) need and water intake. The NRC equation adjusts ME need by 1.95 kcal per degree Celsius above or below the standard thermoneutral zone. 4. Choose or enter your feed: Pick any of the 23 common ingredients and complete feeds from the dropdown, or tick "Enter custom feed composition" and type in your own ME, CP, Ca, available P, Lys, and Met+Cys values. 5. Read the nutrient adequacy panel: Six green or red badges show whether your chosen feed meets ME, CP, Calcium, available Phosphorus, Lysine, and Met+Cys requirements. Red badges include a recommendation for corrective supplementation. 6. Check egg economics (layers): For laying birds, enter the egg selling price per dozen to see daily and annual revenue, daily profit against feed cost, and the break-even laying rate needed to cover feed. FAQ: Q: How much feed does a laying hen need per day? A: A commercial laying hen in peak production typically consumes 100-120 g of complete feed per day, but the NRC (1994) formula ties feed intake directly to metabolisable energy need — which depends on body weight, housing temperature, and egg mass produced. At 20 degrees C, a 2 kg hen laying at 85% with 62 g eggs needs roughly 113 g of a 2,800 kcal/kg layer pellet per day. Cold housing raises ME need; heat above 20 degrees C reduces feed intake but the bird still needs the same nutrients in less feed volume. Q: How much water do chickens drink per day? A: As a rule of thumb, chickens drink about 1.7-2.0 ml of water per gram of feed consumed at thermoneutral temperature. A flock eating 110 g/bird/day therefore needs roughly 190-220 ml per bird. Heat stress increases demand sharply — the calculator adds 10% extra per degree Celsius above 20 degrees C, consistent with industry guidance. Always size drinker capacity to at least twice the calculated daily need. Q: What is the NRC laying-hen ME equation? A: The NRC (1994) Nutrient Requirements of Poultry gives daily ME intake (kcal/bird/day) = BW^0.75 * (173 - 1.95 * T) + 2.07 * egg_mass_g, where BW is body weight in kg, T is ambient temperature in degrees C, and egg_mass_g is egg mass in grams per bird per day. The 0.75 exponent (metabolic body weight) accounts for the non-linear scaling of maintenance energy with body size. The 2.07 factor represents the ME cost of synthesising one gram of egg mass. Q: How much calcium does a laying hen need? A: The NRC (1994) recommends 3.4% calcium in the total diet for peak-production layers, rising slightly to 3.7% for older hens producing larger eggs. Most of this calcium goes directly into eggshell — a single 62 g egg contains about 2.2 g of calcium. Commercial feeds typically supply calcium via limestone or oyster shell at roughly 8-10% of the premix. If your feed shows a red calcium badge, adding a small amount of coarse limestone or crushed oyster shell in a separate free-choice feeder is the standard fix. Q: What FCR should broilers achieve? A: Feed conversion ratio (FCR) benchmarks from Aviagen for the Ross 308 broiler are: starter phase (0-3 weeks) around 1.4 kg feed per kg live-weight gain; grower phase (3-6 weeks) around 1.7; finisher phase (6 weeks to slaughter) around 1.9. Overall batch FCR from day 1 to 42-day slaughter is typically 1.75-1.85. Higher FCR means more feed per kg of meat, which raises cost. Poor litter quality, disease pressure, and suboptimal stocking density are the main drivers of FCR deterioration on real farms. Q: What is the difference between ME and CP in chicken nutrition? A: Metabolisable energy (ME) is the fuel that powers all bodily functions — maintenance, movement, egg synthesis, and muscle growth. It is measured in kcal per kg of feed. Crude protein (CP) is the total nitrogen-containing fraction of the diet, which the bird uses to build muscle, feathers, and eggs. Providing enough ME but too little CP stunts growth and reduces egg production; excess CP wastes money and increases nitrogen excretion. Both must be balanced to the specific production stage, which is why the calculator checks each nutrient independently. Q: How do I calculate the break-even laying rate? A: The break-even laying rate is the minimum percentage of hens that must lay each day for egg revenue to cover feed costs. The calculator divides total daily feed cost by the revenue from one full day of laying (birds divided by 12 times price per dozen) and expresses the result as a percentage. For example, 50 hens eating £2.09/day of feed at a selling price of £1.40/dozen need at least 36% of hens laying to break even on feed alone — well below commercial targets of 85%+, confirming a healthy margin at typical production rates. #### Greenhouse Heating Calculator URL: https://geratools.com/greenhouse-heating-calculator Free greenhouse heating calculator. Enter dimensions, cladding type and design temperatures to find total heat load and recommended heater output (kW and BTU/hr). Supports rectangular, gothic and lean-to shapes. Runs 100% in your browser. How to use: 1. Choose your unit system and shape: Select metric or imperial, then pick rectangular (span roof), gothic/tunnel, or lean-to. The tool calculates surface area and volume automatically. 2. Enter greenhouse dimensions: Type the length, width (span), eave height and ridge height. The calculator derives roof slope, wall areas and internal volume from these four values. 3. Select cladding and glazing type: Pick the material closest to your greenhouse — single glass carries a U-value of 5.8 W/(m²·K), double glass 2.9, twin-wall polycarbonate 3.5, and triple-wall 2.1. Adding a bubble-wrap inner liner drops it to about 2.3. 4. Set your design temperatures: Enter the lowest overnight outside temperature expected in your location (the design temperature) and the minimum inside temperature you want to maintain. 5. Adjust ACH and safety factor: Air changes per hour (ACH) models draughts and ventilation heat loss — use 0.5 for a well-sealed modern structure, 1.0 for a typical greenhouse and 2.0 for an older draughty one. The safety factor (default 1.25) adds 25% headroom for very cold snaps. 6. Read the results: The table splits the load into fabric conduction loss and infiltration loss, shows the percentage each contributes, and gives the final recommended heater output in kW (and BTU/hr) including your safety margin. FAQ: Q: What formula does the greenhouse heating calculator use? A: It uses the standard two-component steady-state method. Fabric (conduction) heat loss is Q_fab = U × A × ΔT, where U is the cladding U-value in W/(m²·K), A is total surface area in m² and ΔT is the temperature difference in Kelvin. Infiltration loss is Q_inf = 0.333 × N × V × ΔT, where N is air changes per hour and V is volume in m³ — the constant 0.333 is the volumetric heat capacity of air (1200 J/(m³·K)) divided by 3600 s/hr. Total load is the sum of both components; the recommended heater output multiplies that by a safety factor. Q: What U-value should I use for my greenhouse? A: Single-layer glass or polyethylene film has a U-value around 5.8 W/(m²·K) — the highest (worst) insulation. Double-glazed units drop to around 2.9. Twin-wall 6 mm polycarbonate is typically 3.5 and triple-wall 10 mm about 2.1. Adding a bubble-wrap inner liner to single glass brings it to roughly 2.3. If you have manufacturer data, use that figure instead. Q: What air change rate (ACH) should I enter? A: For a modern, well-sealed greenhouse with good door seals use 0.5 ACH. A typical older glass greenhouse is around 1.0 ACH. A draughty or poorly sealed structure can be 1.5–2.0. ACH has a big impact on total heat load — improving draught-proofing is often the quickest win before buying a bigger heater. Q: Why is there a safety factor? A: The steady-state formula assumes the coldest possible night persists continuously, which it rarely does. Even so, a 1.25 safety factor (25% extra capacity) is standard practice for horticultural heating — it covers unusually cold snaps, temporary heat loss when doors open, and heater output degradation over time. For tropical or tender crops where a few degrees of frost kills the plants, some growers use 1.5. Q: How do I convert the result to kilowatts for buying a heater? A: The calculator already gives kW directly. To convert to BTU/hr multiply kW by 3,412. Gas heaters in the UK are rated in kW; electric fan heaters and tube heaters are also rated in kW. Oil-fired or LPG cabinet heaters are often labelled in BTU/hr — use the BTU/hr figure shown in the results. Q: Does the calculator include heat loss through the floor? A: No. Ground heat loss through a soil or concrete floor is typically small compared with walls, roof and infiltration in a vented greenhouse, and is conventionally omitted in standard horticultural heat-loss calculations. If your greenhouse has an unusually cold concrete slab or underfloor pipes, add roughly 5–10% to the total as a manual allowance. #### Irrigation Water Calculator URL: https://geratools.com/irrigation-water-calculator Free irrigation water calculator. Compute gross irrigation requirement (GIR), daily water volume in m³ and litres, and required flow rate for drip, sprinkler, furrow or flood systems. Uses FAO-56 Kc coefficients and the Hargreaves-Samani ET0 formula. 100% browser-based. How to use: 1. Choose your ET0 input method: Either type a known reference evapotranspiration value (mm/day) from a met service, or switch to Hargreaves-Samani mode and enter Tmax, Tmin, latitude, and day of year to estimate it automatically. 2. Select your crop and growth stage: Pick from the dropdown of common crops (maize, wheat, rice, tomato, etc.) to load the FAO-56 mid-season Kc coefficient, or choose Custom and enter your own Kc value. 3. Enter field area and effective rainfall: Type your irrigated area in hectares and the average effective rainfall in mm/day. Effective rainfall is the portion of precipitation that stays in the root zone. 4. Choose your irrigation system: Select drip (90%), sprinkler (75%), furrow (60%), or flood (45%) to apply the correct application efficiency, or tick Override to enter a site-measured efficiency. 5. Set daily irrigation hours: Enter how many hours per day you plan to run the system. This converts the daily water volume into a required flow rate (L/h and m3/h). 6. Read the results: The calculator shows GIR in mm/day, total volume in m3 and litres per day, required flow rate, weekly volume, and a 90-day seasonal total with a full step-by-step working table. FAQ: Q: What is the Gross Irrigation Requirement (GIR)? A: GIR is the total water depth (mm/day) that must be applied at the field inlet to meet the crop's net water need after accounting for system losses. The formula is GIR = (ETc - Re) / Ea, where ETc is crop evapotranspiration, Re is effective rainfall, and Ea is application efficiency. Because no system delivers water perfectly, GIR is always greater than the net requirement. Q: What is ET0 and how is it estimated? A: ET0 (reference evapotranspiration) is the water use rate of a hypothetical well-watered reference grass surface under local climate conditions, expressed in mm/day. The most accurate method is the FAO Penman-Monteith equation, which needs net radiation, wind speed, humidity, and temperature. When only temperature data are available, this calculator uses the Hargreaves-Samani (1985) formula (ET0 = 0.0023 x Ra x (Tmean + 17.8) x (Tmax - Tmin) raised to the power 0.5), which requires only daily maximum and minimum temperature plus extraterrestrial radiation estimated from latitude and day of year. Q: What is the Kc (crop coefficient)? A: Kc is a dimensionless factor that converts ET0 to actual crop water use (ETc = ET0 x Kc). It varies by crop species and growth stage. This calculator uses mid-season Kc values from FAO Irrigation and Drainage Paper 56 (Allen et al., 1998). Mid-season represents peak demand; early-season and late-season Kc values are lower. If you have measured local Kc data, use the Custom option. Q: Why does the volume use a factor of 10? A: One millimetre of water depth applied over one hectare equals exactly 10 cubic metres: 1 mm = 0.001 m, and 1 ha = 10,000 m2, so 0.001 m x 10,000 m2 = 10 m3. Multiplying GIR (mm/day) by area (ha) by 10 converts the irrigation depth into a volumetric flow the pump or canal must supply. Q: What irrigation efficiency values should I use? A: Typical application efficiencies are 85-95% for well-maintained drip and micro-irrigation, 70-80% for sprinklers, 55-65% for properly managed furrow, and 40-50% for flood or basin irrigation. Higher efficiency means less water is lost to runoff and deep percolation. If you have water-balance measurements for your specific field, use the Override option to enter a more precise value. Q: How do I convert mm/day GIR to a pump flow rate? A: Volume (m3/day) = GIR x area x 10. Divide by irrigation hours per day to get m3/h, then multiply by 1000 for L/h. For example, GIR = 8 mm/day on a 2 ha field with 8 h/day irrigation gives 8 x 2 x 10 = 160 m3/day, or 20 m3/h (20,000 L/h), which is about 333 L/min. Size your main line, pump curve, and pressure rating for this flow. #### Hay Bale Calculator URL: https://geratools.com/hay-bale-calculator Free hay bale calculator: work out bale volume (round or square), packing density, dry matter per bale and the total number of bales required to feed your herd through winter. Metric and imperial. Runs entirely in your browser. How to use: 1. Choose your bale type: Pick a preset (large round, small square, etc.) or select Custom and enter your own diameter and width for round bales, or width, height and length for square bales. 2. Enter bale weight and dry matter content: Typical hay dry matter is 83-87%. Silage bales wrapped in plastic sit lower at 60-70%. The calculator uses this to find usable dry matter per bale. 3. Fill in your herd details: Enter the number of animals, their average body weight and how many days you need to feed them. Adjust the dry-matter intake percentage (default 2.5% BW) for your species and system. 4. Read the bale count and storage footprint: The results panel shows bales needed, total hay tonnage and the estimated ground footprint for a single-layer stack so you can check it fits your barn or yard. FAQ: Q: How is round bale volume calculated? A: A round bale is a cylinder, so V = (pi / 4) times diameter squared times width. For a 1.5 m diameter bale that is 1.5 m wide the volume is roughly 2.65 m3. Packing density (kg/m3) is the bale weight divided by that volume. Q: How much dry matter does a hay bale contain? A: It depends on bale weight and moisture. A 400 kg round bale at 85% dry matter contains 340 kg of dry matter. Wet silage bales (60% DM) at the same weight yield only 240 kg DM, so you would need roughly 40% more bales for the same feeding value. Q: How many hay bales does a cow need for winter? A: A 500 kg beef cow eating 2.5% of her body weight in dry matter per day needs about 12.5 kg DM/day. Over 180 days that is 2,250 kg DM. At 340 kg DM per large round bale you would need approximately 7 bales per cow. For 20 cows that is around 133 bales. Q: What dry-matter intake percentage should I use? A: Beef cattle typically need 2.0-2.5% of body weight in DM per day for maintenance. Dairy cows in milk can need 3.0-3.5%. Sheep eat roughly 2.5-3.0% BW. The calculator defaults to 2.5%, which is a safe middle estimate for dry beef cattle or dry ewes. Q: How do I account for hay waste? A: The calculator gives the theoretical bales needed based on dry matter. In practice you should add 10-20% for ring-feeder wastage with round bales or 5-10% for covered square bale systems. Multiply the bale count by 1.15 as a conservative allowance. Q: What is the difference between dry matter and as-fed weight? A: As-fed weight is what you physically lift. Dry matter (DM) is what remains after all water is removed. A 400 kg bale at 85% DM contains 400 times 0.85 = 340 kg DM and 60 kg water. Animals need DM to meet their energy and protein requirements, so always base ration calculations on DM, not as-fed weight. #### Silage Calculator URL: https://geratools.com/silage-calculator Free silage calculator. Convert clamp volume to fresh-weight and dry-matter tonnage, estimate yield from field area, and work out how many days a silage store will last your livestock. Supports maize, grass, wholecrop and more. 100% client-side. How to use: 1. Pick your crop type: Select from maize, grass (1st or 2nd cut), wholecrop, lucerne or enter custom DM% and density values. 2. Choose a calculation mode: Pick one of three modes: clamp volume to weight, field area to yield, or store size to feeding days. 3. Enter your measurements: Fill in the clamp dimensions (or field area and yield, or store weight and livestock numbers). 4. Read the results: The tool instantly shows fresh weight, dry-matter weight, available tonnage after losses, and feeding days where relevant. FAQ: Q: What is dry matter (DM) in silage? A: Dry matter is what remains after all the water is removed from the fresh crop. A grass silage at 25% DM contains 25 kg of actual nutritional material per 100 kg of fresh silage. Feed budgets are always planned on a DM basis because the water content varies between batches. Q: How is clamp density calculated? A: Clamp density is the fresh weight per cubic metre of compacted silage, typically 650-750 kg/m3 for grass and 700-750 kg/m3 for maize. The calculator multiplies your clamp volume (L x W x H) by this density to give fresh weight, then applies the DM percentage to derive dry-matter tonnes. Q: What shrinkage figure should I use? A: Shrinkage covers fermentation gas losses (4-6%), effluent run-off (2-5%) and face/shoulder losses during feedout (2-4%). Grass silage at 25% DM typically loses 10-15% overall; maize at 30% DM loses 8-12%; wholecrop loses 6-10%. Well-sealed, well-compacted clamps sit at the lower end of these ranges. Q: How many tonnes of silage does a hectare of grass produce? A: A productive first-cut grass silage field in the UK typically yields 20-30 fresh tonnes per hectare (5-7.5 t DM/ha). Second-cut yields are lower (15-20 t fresh/ha). Maize yields are higher, commonly 35-45 fresh tonnes per hectare (10-14 t DM/ha). Enter your own figures for accurate results. Q: How do I estimate feeding days for a dairy herd? A: A high-yielding dairy cow eats roughly 14-18 kg of DM per day, which equates to 50-70 kg of fresh grass silage at 25% DM. The calculator divides your store DM (after shrinkage losses) by total herd DM demand to give feeding days. Always keep a buffer of at least 2-3 weeks in case of a late spring or poor second cut. Q: What is a good dry matter for ensiling? A: Grass should be wilted to 25-30% DM before ensiling for an optimal balance between fermentation quality and effluent risk. Below 20% DM generates large volumes of effluent and nutrient loss; above 35% DM is difficult to consolidate and risks aerobic instability (heating). Maize is usually harvested at 28-35% DM at the whole-plant stage. ### Home & DIY #### 3D Print Total Cost Per Gram URL: https://geratools.com/3d-print-cost-per-gram Calculate the all-in cost per gram of a 3D print by combining filament price, electricity, printer depreciation over its rated lifetime, and a failure rate. A realistic cost basis for quoting print services. Runs in your browser. How to use: 1. Enter print weight and time: Type the grams of filament and the print time in hours, both of which your slicer reports after slicing. 2. Add machine and energy figures: Enter your spool price, printer wattage and electricity rate, plus the printer's purchase price and its rated lifetime in hours. 3. Read the all-in cost: The tool shows material, electricity, and depreciation separately, applies your failure rate, and gives a final all-in cost per gram for quoting. FAQ: Q: Why is cost per gram higher than just the filament price? A: Filament is only one of four costs. Electricity to run the printer, depreciation of the machine itself over its rated life, and the cost of failed prints all add real money. This tool sums them so your quotes cover the true cost of goods. Q: How is machine depreciation calculated? A: Depreciation per hour is the printer's purchase price divided by its rated lifetime in hours. Multiplying by the print time gives the wear cost for that job. A 500 unit printer rated for 5000 hours costs 0.10 per print hour. Q: How does the failure rate change the cost? A: Failed prints still consume material, power, and machine time. The tool divides the base cost by (1 minus the failure rate) so that successful prints absorb the cost of the failures. An 8 percent failure rate multiplies cost by about 1.087. Q: What electricity figures should I use? A: Use your printer's average power draw in watts, not its peak heater rating. A typical desktop FDM machine averages 80 to 150 watts. Multiply by hours and divide by 1000 to get kilowatt-hours, then by your per-kWh rate. Q: Does this include my labour? A: No. This is the cost of goods only: material, energy, depreciation, and failures. Add your hourly labour for setup, supervision, and post-processing, plus a profit margin, on top of the figure shown. #### 3D Print Scale Factor Calculator URL: https://geratools.com/3d-print-scale-factor Computes the uniform or per-axis scale percentage to type into your slicer to resize a 3D model from its original size to a target size. Handles proportional scaling from one known axis and independent X/Y/Z scaling with a distortion warning. How to use: 1. Choose uniform or per-axis: Use uniform mode to scale the whole model proportionally from one known dimension. Use per-axis mode to scale X, Y and Z independently. 2. Enter original and target sizes: Type the model's current dimension and the size you want, in millimetres. In per-axis mode, fill in all three original and target values. 3. Apply the percentage in your slicer: Copy the resulting percentage into your slicer's scale field, where 100% means original size. The tool flags whether per-axis scaling distorts the model. FAQ: Q: How do I calculate a 3D print scale percentage? A: Divide the target size by the original size and multiply by 100: scale% = (target / original) × 100. For example, scaling a 40 mm part to 55 mm needs 55/40 × 100 = 137.5%. Enter that percentage in your slicer's uniform scale field. Q: Will scaling one axis change the others? A: In uniform (proportional) scaling, yes — every axis is multiplied by the same percentage so the model keeps its shape. If you only want one axis to change while the others stay fixed, use per-axis mode and turn off 'uniform scaling' in your slicer. Q: What does per-axis scaling do? A: Per-axis scaling applies a different percentage to X, Y and Z. This stretches or squashes the model. The calculator computes each axis percentage independently and warns you when they differ, because unequal scaling distorts the geometry and can ruin fits and round features. Q: Does scaling affect wall thickness? A: Yes. Scaling down also shrinks walls and small features, which may fall below your nozzle diameter and fail to print. After scaling, check that the thinnest walls are still at least one or two line widths thick, and that holes and pins are large enough to survive the slicer. Q: Why is my scaled part the wrong size after printing? A: If the slicer percentage is correct but the print is off, the cause is usually printer calibration — steps-per-mm, flow, or thermal shrinkage — not the scale math. Calibrate your axes and material shrinkage first, then apply the scale percentage from this calculator on top of a well-calibrated machine. #### 3D Print Thread Sizing Chart URL: https://geratools.com/3d-print-thread-sizing Calculate the tap-drill and adjusted hole diameter for 3D-printed internal threads across ISO metric and imperial UNC/UNF standards. Accounts for FDM layer resolution and elephant-foot tolerance so printed threads actually fit. How to use: 1. Pick the thread standard and size: Choose ISO metric (M3, M4, M5…) or imperial UNC/UNF, then select the nominal size you want a fastener to thread into. 2. Set your printer tolerance: Enter the horizontal expansion (elephant-foot) compensation your printer typically shows, in millimetres. A well-tuned FDM machine is around 0.1 to 0.2 mm. 3. Read the modelled hole diameter: The tool shows the standard 75 percent tap-drill diameter and the FDM-adjusted hole diameter to use in your CAD model so the printed thread fits the fastener. FAQ: Q: Why can't I just model the exact thread diameter? A: FDM printers over-extrude slightly at internal walls, so a hole prints smaller than modelled. To get a usable internal thread you model the standard tap-drill size and then enlarge it by your printer's horizontal expansion so the printed result lands on target. Q: What is the tap-drill diameter? A: It is the hole diameter that leaves about 75 percent thread engagement when cut with a tap. For metric coarse threads it equals the nominal diameter minus the pitch. For M5 x 0.8 that is 5.0 minus 0.8 = 4.2 mm. Q: Should I print the thread or tap it after printing? A: For threads M4 and smaller, printing a plain hole and cutting it with a steel tap gives the strongest, most accurate result. Larger threads (M6 and up) can be modelled directly with a thread feature, but still benefit from tolerance compensation. Q: Does layer height affect thread fit? A: Yes. Coarser layers (0.28 mm+) blur fine thread profiles and reduce engagement, especially on threads printed vertically. Use 0.12 to 0.16 mm layers for printed threads, and prefer cutting a tap for anything finer than M5. Q: What horizontal expansion value should I use? A: Print a 20 mm calibration cube and measure a hole of known modelled size. The difference between modelled and measured diameter is your horizontal expansion. Typical PLA values fall between 0.1 and 0.25 mm; enter your measured figure for best accuracy. #### Candle Wax & Fragrance Calculator URL: https://geratools.com/candle-wax-fragrance-calculator Enter vessel volume, fragrance load percentage, and wax type to compute the exact wax weight and fragrance oil needed, with a safe-load warning. For candle makers using soy, paraffin, coconut, or beeswax. How to use: 1. Pick your wax and vessel: Select your wax type and enter the volume of one vessel along with how many vessels you are pouring. 2. Set fill level and fragrance load: Choose how full you pour the vessel and the fragrance load as a percentage of wax weight, typically 6-10%. 3. Read wax and fragrance amounts: The tool returns total wax weight and the matching fragrance oil weight, and warns you if the load is unsafe for that wax. FAQ: Q: How do you turn vessel volume into wax weight? A: The vessel volume is converted to millilitres and multiplied by the fill level, then by the wax density. Most candle waxes are slightly less dense than water at about 0.9 grams per millilitre, so an 8 oz vessel holds roughly 210 grams of wax when filled to 90 percent. Q: Is fragrance load a percentage of wax or of total weight? A: By industry convention, fragrance load is a percentage of the wax weight, not the combined total. So 8 percent on 200 grams of wax means 16 grams of fragrance oil. This tool follows that convention. Q: How much fragrance can I safely add? A: Most waxes top out around 8-12 percent fragrance load, but soy and beeswax hold less than coconut blends. Above the safe maximum the oil can seep out, cloud the wax, or cause sooting and poor burns. Always check your specific wax's stated maximum. Q: Why do different waxes hold different amounts of fragrance? A: Fragrance binding depends on the wax's molecular structure. Coconut and coconut-soy blends bind oil well and take higher loads; pure soy and beeswax bind less and can sweat oil if overloaded. The tool flags loads above each wax's typical ceiling. Q: Should I weigh or measure by volume? A: Weigh everything. Candle making is a weight-based craft: weigh the wax, then weigh the fragrance to hit the exact percentage. Volume measurement of viscous wax and oil is far less accurate and leads to inconsistent scent throw. #### Concrete Anchor Pullout Strength Calculator URL: https://geratools.com/concrete-anchor-pullout-calculator Calculates the concrete breakout cone strength for a single cast-in or post-installed anchor per ACI 318-19 Chapter 17. Enter concrete f'c, embedment depth, and edge distance to get the design tension breakout strength with edge-distance reduction applied. How to use: 1. Enter concrete and anchor data: Type the concrete compressive strength f'c, the effective embedment depth hef, and whether the anchor is cast-in or post-installed. 2. Add the edge distance: Enter the smallest distance from the anchor centre to a free concrete edge. The tool applies the ACI edge-distance reduction when the anchor is close to an edge. 3. Read the design strength: The tool returns the nominal breakout strength Ncb and the strength-reduced design value phi*Ncb for a single anchor in tension. FAQ: Q: Which ACI equation does this use? A: It uses the concrete breakout strength equation from ACI 318-19 Chapter 17 (formerly Appendix D): Nb = kc * lambda * sqrt(f'c) * hef^1.5 for cast-in anchors. The single-anchor projected area ANc is taken as the full 9*hef^2 cone with an edge-distance reduction factor when applicable. Q: What is kc? A: kc is the breakout coefficient: 24 for cast-in anchors and 17 for post-installed anchors when using US customary units (pounds and inches). The tool selects the right value based on your anchor type choice. Q: Does this cover steel and pullout failure modes? A: No. This tool isolates the concrete breakout mode, which often governs for shallow embedments near edges. A full design must also check steel tensile strength, pullout, side-face blowout, and any combined shear interaction before accepting a capacity. Q: What edge distance triggers a reduction? A: ACI sets the critical edge distance for breakout at 1.5*hef. When your edge distance is less than that, the projected breakout area is clipped, so the tool reduces the strength proportionally. At or beyond 1.5*hef there is no edge reduction. Q: Is this a substitute for an engineer? A: No. It is an estimating aid for one failure mode. Anchorage to concrete is life-safety work and must be checked and stamped by a licensed engineer against the full ACI 318 provisions and the manufacturer's evaluation report. #### Drywall Sheet Calculator URL: https://geratools.com/drywall-sheet-calculator Calculates drywall sheet count for the walls and ceiling of any room, deducting door and window cutouts. Choose 4×8, 4×9, or 4×12 sheets and get screw count, joint tape in feet, and joint compound in gallons for a standard 3-coat finish. How to use: 1. Enter room dimensions: Type the room length, width, and ceiling height in feet, and whether you are hanging the ceiling as well as the walls. 2. Set openings and sheet size: Enter the number of doors and windows so their area is deducted, then choose a 4×8, 4×9, or 4×12 sheet. 3. Read sheets and materials: The tool shows total board area, sheets needed with waste, and estimated screws, joint tape, and joint compound for a 3-coat finish. FAQ: Q: How many drywall sheets do I need for a room? A: Find the total wall and ceiling area, subtract openings, then divide by the area of one sheet (32 sq ft for 4×8, 48 sq ft for 4×12) and add about 10 percent for waste. A 12 by 12 foot room with 8 foot walls needs roughly 12 to 14 sheets of 4×8. Q: How many screws per sheet of drywall? A: A common figure is about 32 screws per 4×8 sheet on walls at 16 inch stud spacing — roughly one screw per square foot. Ceilings use a tighter pattern and slightly more. The tool scales screws by total board area at about one per square foot. Q: How much joint tape do I need? A: Tape every seam between sheets plus the inside corners. A rough estimate is about 0.4 linear feet of tape per square foot of board. The tool uses that ratio, so a 500 square foot job needs roughly 200 feet of tape. Q: How much joint compound for a 3-coat finish? A: The common industry rule of thumb is about one gallon of ready-mix compound per 100 square feet of board for a full tape, fill, and finish sequence. That works out to roughly one 4.5-gallon bucket per 450 square feet — so a typical room needs about one bucket, with a small buffer for the finish coat. Q: Should I hang the ceiling first? A: Yes. Hang the ceiling before the walls so the top wall sheets push up and support the ceiling edges, giving tighter joints. The calculator can include or exclude the ceiling so your sheet count matches your plan. #### Earthwork Swell & Shrinkage Calculator URL: https://geratools.com/earthwork-spoil-factor-calculator Converts between bank (in-place), loose (truck), and compacted soil volumes using swell and shrinkage factors for common soil types. Enter a volume in any of the three states to get the other two, plus an estimate of truck loads needed to haul the loose material away. How to use: 1. Pick the soil type: Choose the material — sand, gravel, common clay, rock, or topsoil — to load typical swell and shrinkage percentages, or override them with your own. 2. Enter a known volume: Type a volume and say whether it is bank (in-place), loose (in the truck), or compacted (placed fill). The tool converts to the other two states. 3. Read volumes and truck loads: The tool shows bank, loose, and compacted volumes side by side, and divides the loose volume by your truck capacity to estimate the number of loads. FAQ: Q: What is swell? A: When you excavate soil it loosens and takes up more space than it did in the ground. Swell is that increase. A swell of 25 percent means 100 cubic yards of bank material becomes 125 cubic yards loose in the truck. The load factor is 1 divided by (1 plus swell). Q: What is shrinkage? A: When loose soil is placed and compacted as fill, it consolidates to less than its original bank volume. Shrinkage of 10 percent means 100 cubic yards of bank material only makes 90 cubic yards of compacted fill, so you need to dig more than the fill volume suggests. Q: How do I convert bank to compacted? A: Compacted volume equals bank volume times (1 minus shrinkage). To find how much bank material a target fill needs, divide the compacted volume by (1 minus shrinkage). The tool does both directions automatically from whichever state you enter. Q: Why does loose volume matter for hauling? A: Trucks carry loose, swelled material, not in-place bank measure. To size your haul you must convert bank to loose first. Entering a 20 cubic yard bed, the tool divides the loose volume by 20 and rounds up to give the number of truck loads. Q: Where do these percentages come from? A: Swell and shrinkage vary by soil. The defaults here are typical mid-range values from earthwork references: sand swells about 12 percent, common clay about 25 percent, solid rock 50 percent or more. Always use site-specific soil test data when you have it. #### Fascia, Soffit & Eave Material Calculator URL: https://geratools.com/fascia-soffit-calculator Calculates linear feet of fascia board, square footage of soffit panel, and J-channel runs for roof eaves and gables. Enter the roof perimeter, eave and gable overhang widths, and a waste factor to get a clean material take-off for vinyl, aluminium, or plywood soffit systems. How to use: 1. Enter the eave and gable lengths: Type the total length of horizontal eaves and the total length of sloped gable rakes around the roof, in feet. 2. Set the overhang width: Enter how far the roof overhangs the wall at the eave. This width sets the depth of soffit panel you must cover. 3. Read the take-off: The tool returns fascia linear feet, soffit square footage, and J-channel runs, each adjusted by your waste factor and rounded for ordering. FAQ: Q: How is fascia length found? A: Fascia runs along the eave at the roof edge plus along the gable rakes. The tool adds the eave length and gable length, applies waste, and reports the total linear feet of fascia board or capping you need. Q: How is soffit area calculated? A: Soffit covers the underside of the overhang. Its area is the eave length multiplied by the overhang width. With a 16 in overhang and 120 ft of eave, that is 120 * 1.333 = 160 sq ft before waste. Q: What is J-channel used for here? A: J-channel receives the cut edge of soffit panel where it meets the wall and where it returns at the fascia. The tool estimates roughly two J-channel runs along the eave length (wall side and fascia side) plus the gable, then applies waste. Q: What waste factor is reasonable? A: Straight runs of fascia and soffit waste little — about 5 to 8 percent. Roofs with many corners, returns, and short runs waste more because of cuts. The tool defaults to 8 percent and lets you adjust it. Q: Does gable overhang need soffit? A: Often the gable rake has a narrow or zero soffit. The tool focuses soffit area on the horizontal eave overhang, where boxed soffit is standard. If your gable has a boxed return, add that area into the overhang accordingly. #### Supply Grille/Diffuser Velocity & CFM Calculator URL: https://geratools.com/hvac-cfm-grille-velocity-calculator Converts between grille neck dimensions, net free area factor, face velocity in FPM, and airflow in CFM using Q = V times A, and flags when velocity exceeds the ASHRAE noise limit for the room type. For HVAC technicians balancing air distribution. Runs in your browser. How to use: 1. Choose what to solve for: Pick CFM if you measured velocity with a meter, or velocity if you know the design airflow and want to check the grille size. 2. Enter the grille details: Type the neck width and height in inches and the net free area factor, then the measured velocity or the target CFM. 3. Read airflow and noise check: The tool returns CFM or velocity using Q = V times A and warns if face velocity exceeds the ASHRAE noise limit for the selected room. FAQ: Q: How do I calculate CFM from a grille velocity reading? A: Multiply the measured face velocity in feet per minute by the net free area of the grille in square feet: CFM equals velocity times area. The net free area is the grille's open portion, found by multiplying gross neck area by a free area factor of about 0.7 to 0.8. Q: What is the net free area factor? A: Grille bars and frames block part of the opening, so air only passes through the free area. The factor is the open fraction of the gross neck area, typically 0.7 to 0.8 for standard bar grilles. Diffusers and the exact model can vary, so use the manufacturer figure when available. Q: Why does face velocity cause noise? A: Air moving fast across grille bars generates turbulence and whistling. ASHRAE publishes recommended maximum face velocities by space type, from about 500 FPM for quiet libraries to 1000 FPM for noisy stores, to keep that noise acceptable. Q: Should I use gross or net area for velocity? A: Use net free area. Face velocity is the speed of air through the open portion of the grille, so dividing CFM by net area, not gross neck area, gives the velocity that determines noise and throw. Q: What CFM should each register deliver? A: That comes from the room's design airflow, which depends on the cooling or heating load. Once you know the target CFM per register, this tool checks whether the chosen grille size keeps velocity within the noise limit. #### Evaporator / Condenser Coil Airside Pressure Drop Calculator URL: https://geratools.com/hvac-coil-airside-pressure-drop Estimates finned-coil airside resistance in inches of water column from face velocity and coil row depth using empirical pressure-drop versus velocity curves for 2-, 4-, 6- and 8-row coils, feeding the total external static pressure for blower selection. Runs in your browser. How to use: 1. Enter airflow and coil face area: Type the design CFM and the coil face area in square feet, or enter the face velocity directly if you already know it. 2. Choose the coil row depth: Pick 2, 4, 6 or 8 rows to match your coil so the tool uses the correct empirical pressure-drop curve. 3. Read the airside drop: The tool returns the wet-coil airside pressure drop in inches of water column to add into your total external static pressure. FAQ: Q: How does face velocity drive coil pressure drop? A: Airside pressure drop rises roughly with the square of face velocity for a given coil. Doubling velocity from 300 to 600 FPM increases the drop about four-fold, which is why staying near 400 to 500 FPM is the usual design sweet spot for cooling coils. Q: Why does it matter whether the coil is wet or dry? A: On a cooling coil that is dehumidifying, condensate clings to the fins and adds resistance. A wet coil typically has 20 to 40 percent higher airside pressure drop than the same coil running dry, so this tool applies a wet-coil factor by default for evaporator coils. Q: What face velocity should I design for? A: Cooling coils are normally sized for 400 to 500 FPM face velocity. Above about 550 FPM condensate can be blown off the coil and carried downstream, and noise and pressure drop climb fast. Below 300 FPM the coil and cabinet get oversized and expensive. Q: Where does this number go in my calculation? A: The coil airside drop is one component of the total external static pressure the blower must overcome. Add it to filter, duct, register, damper and other accessory losses to get the total, then select a blower and speed that delivers your CFM at that static pressure. Q: Are these numbers exact for my specific coil? A: No. They are representative curves for typical aluminum-fin, copper-tube coils at common fin spacing. For final design always use the manufacturer's published coil selection software, which accounts for exact fin density, tube pattern and circuiting. Use this tool for early sizing and sanity checks. #### Ductwork Heat Gain / Loss Calculator URL: https://geratools.com/hvac-ductwork-heat-gain-loss-calculator Uses duct surface area, insulation R-value, and the temperature difference between the air inside the duct and the surrounding attic or crawlspace to compute conductive BTU/h of duct heat gain or loss, per the ACCA Manual J duct-loss approach. Runs entirely in your browser. How to use: 1. Enter the duct surface area: Either enter the total duct surface area directly, or give a round-duct diameter and length and let the tool compute the surface area for you. 2. Set insulation and temperatures: Enter the duct insulation R-value, the air temperature inside the duct, and the temperature of the unconditioned space the duct passes through. 3. Read the heat gain or loss: The tool computes the conductive BTU/h through the duct walls and shows whether it is a gain or a loss, plus the loss per square foot. FAQ: Q: What is the duct heat loss formula? A: Conductive heat transfer is the surface area divided by the insulation R-value, multiplied by the temperature difference between the duct air and the surrounding space. Q in BTU/h equals A in square feet times delta-T in Fahrenheit divided by R. Q: Why does duct location matter so much? A: A duct in conditioned space loses heat back into the conditioned area, so it is not truly lost. A duct in a 130 degree attic or a 40 degree crawlspace sees a huge temperature difference, so it gains or loses real energy that never reaches the rooms. Q: What R-value should attic ducts have? A: Modern energy codes typically require R-6 to R-8 for ducts in unconditioned attics, and R-8 or higher in extreme climates. Older flex duct may be only R-4.2. Higher R-value lowers the heat transfer in direct proportion. Q: Does this include air leakage losses? A: No. This tool calculates only conductive loss through the duct walls. Air leakage from poorly sealed joints can equal or exceed conduction in leaky systems. Seal joints with mastic and test with a duct blaster to address leakage separately. Q: How do I use the result in a load calculation? A: Add the duct gain or loss to the room or system load it serves. ACCA Manual J handles this with a duct-loss percentage, but a direct conductive estimate like this is useful for spot-checking a long run through a hot attic or cold crawlspace. #### HVAC Economizer Free-Cooling Hours Calculator URL: https://geratools.com/hvac-economizer-savings-calculator Counts annual hours where outdoor conditions allow air-side free cooling using bundled bin-hour data for major US climate zones, then multiplies by system tonnage and efficiency to estimate kWh and dollar savings of an economizer versus mechanical cooling alone. Runs in your browser. How to use: 1. Pick the climate zone: Select the US city closest to your project. Each carries bundled annual bin-hour data describing how many hours fall below the free-cooling temperature threshold. 2. Enter system size and efficiency: Type the cooling system tonnage and its full-load efficiency (kW per ton or COP) so the tool knows the compressor energy displaced per free-cooling hour. 3. Read the savings: The tool counts qualifying free-cooling hours, computes the displaced compressor kWh, and multiplies by your electricity rate for an annual dollar estimate. FAQ: Q: How does an air-side economizer save energy? A: When outdoor air is cool and dry enough, an economizer opens outside-air dampers and uses that air directly for cooling instead of running the compressor. Every hour of free cooling displaces the compressor energy that would otherwise be drawn for that load. Q: What is a bin hour? A: Bin-hour data groups the 8,760 hours of a typical year by outdoor temperature range. Counting the hours that fall below the economizer changeover temperature tells you how many hours per year free cooling is available in that climate. Q: Why does climate zone matter so much? A: A mild marine climate like Seattle offers thousands of free-cooling hours, while a hot humid climate like Miami offers very few. The bundled bin data captures this so the savings reflect your actual location rather than a generic figure. Q: What efficiency figure should I enter? A: Use the system's rated full-load efficiency. For packaged rooftop units this is often given as kW per ton; smaller systems may give a COP or SEER. The tool converts your input to kW per ton to compute displaced compressor energy. Q: Is this a guaranteed savings number? A: No. It is an engineering estimate using typical bin data and assumes the economizer runs at full benefit during qualifying hours. Real savings depend on part-load operation, internal loads, controls quality, and humidity limits. Treat it as a justification estimate, not a guarantee. #### Makeup Air Unit (MAU) CFM Calculator URL: https://geratools.com/hvac-makeup-air-cfm-calculator Sums total exhaust CFM from hoods, restrooms, and labs, subtracts an infiltration credit, and computes required makeup air supply CFM to maintain slightly negative or neutral building pressure. Also sizes the MAU heating capacity from the design temperature rise at that flow rate. Runs in your browser. How to use: 1. Enter exhaust totals: Add the exhaust CFM for each source — kitchen hoods, restroom fans, lab fume hoods — to build the total air being removed from the building. 2. Set pressurization target: Choose the percentage of exhaust to replace. Slightly under 100% keeps the space mildly negative (typical for kitchens); 100% is neutral. 3. Read MAU size and heat load: The tool shows required makeup air CFM and the heating BTU/h needed to raise that air from the winter design temperature to the supply target. FAQ: Q: Why does makeup air need to be sized separately? A: Every cubic foot of air a building exhausts must be replaced. If makeup air is not provided, the building goes strongly negative, doors are hard to open, combustion appliances can backdraft, and exhaust hoods lose capture. The MAU deliberately supplies that replacement air. Q: Should makeup air equal 100% of exhaust? A: Usually slightly less. Commercial kitchens are kept mildly negative — often supplying 80 to 90% of exhaust as dedicated makeup air — so cooking odors do not migrate into dining areas. The remaining air comes from adjacent conditioned spaces and infiltration. Q: What is the infiltration credit? A: Some replacement air naturally leaks in through the envelope. Subtracting a modest infiltration credit from required makeup air avoids oversizing the MAU. Tight modern buildings have little infiltration, so keep the credit small unless you have a measured air-change figure. Q: How is the heating capacity calculated? A: Heating BTU/h equals 1.08 times the makeup air CFM times the temperature rise from winter design temperature to the supply setpoint. The 1.08 factor is the standard sensible-heat constant for air at sea level. Q: Does this size cooling for the makeup air? A: This tool sizes only sensible heating, the dominant load for tempered makeup air in cold climates. Cooling and dehumidification of makeup air in hot, humid climates require a separate latent-load calculation and are not covered here. #### Refrigerant Pressure-Temperature (PT) Chart URL: https://geratools.com/hvac-refrigerant-pt-chart Interactive refrigerant pressure-temperature chart that converts gauge pressure in psig to saturation temperature for common HVACR refrigerants including R-22, R-410A, R-32, R-134a, R-404A, R-407C and R-454B, with bubble and dew points for blends. Runs in your browser. How to use: 1. Pick the refrigerant: Select the refrigerant in your system, such as R-410A, R-22, R-454B, or R-134a, from the list. 2. Enter the gauge pressure: Type the reading from your manifold gauge in psig; the tool converts to absolute pressure internally. 3. Read the saturation temperature: The tool returns the saturation temperature; for zeotropic blends it shows both bubble point (liquid line) and dew point (suction line) for superheat and subcool checks. FAQ: Q: How does the chart convert pressure to temperature? A: Each refrigerant has a saturation curve fitted with Antoine-style coefficients that relate absolute pressure to saturation temperature. The tool adds standard atmospheric pressure (14.696 psi) to your gauge reading to get absolute pressure, then solves the curve for the matching temperature. Q: What is the difference between bubble and dew point? A: Zeotropic blends like R-410A, R-404A, R-407C, and R-454B boil over a temperature range called glide. The bubble point is where liquid just starts to boil (used for subcooling on the liquid line); the dew point is where the last vapor condenses (used for superheat on the suction line). Near-azeotropic blends have small glide; R-22, R-32, and R-134a are single-component or azeotropic with no glide. Q: Which value do I use for superheat and subcooling? A: Use the dew-point saturation temperature with the suction (low-side) pressure for evaporator superheat, and the bubble-point saturation temperature with the liquid-line (high-side) pressure for condenser subcooling. Mixing them up on a glide refrigerant skews your charge. Q: Is psig the same as the gauge reads? A: Yes, manifold gauges read in psig (pounds per square inch gauge), which is pressure above atmospheric. The tool adds 14.696 psi to convert to psia (absolute) before solving the saturation curve. At sea level a gauge reading of 0 psig equals 14.696 psia. Q: How accurate is this chart? A: The fitted curves match published refrigerant tables within about 1 to 2 degrees Fahrenheit across the normal HVACR operating range. For critical charging or laboratory work, verify against the manufacturer's official PT chart, but for field service this accuracy is well within practical tolerance. #### Knitting Blocking Dimensions Calculator URL: https://geratools.com/knitting-blocking-dimensions-calculator Enter your dry knit measurements and expected blocking growth percent by fibre (wool 5-20%, superwash 10-15%, cotton -5 to 0%) to compute the target pin-out dimensions for blocking lace and garments accurately. How to use: 1. Measure your piece dry: Measure the width and length of your finished, unblocked knitting flat and enter both in your preferred unit. 2. Pick a fibre or set custom growth: Choose the fibre preset to load a typical growth percentage, or type your own percent from a swatch test for an exact result. 3. Read the pin-out target: The tool applies the growth percentage to both dimensions and shows the size to pin out to when wet blocking. FAQ: Q: Why does blocking change the size? A: Wet fibres relax and the stitches open up, so the fabric grows when pinned out. The amount depends on the fibre: untreated wool and especially lace grow a lot, superwash grows and can keep growing, while cotton and linen barely move or even shrink. Q: What growth percentages are typical? A: Untreated wool grows roughly 5 to 20 percent, with open lace at the high end. Superwash wool grows about 10 to 15 percent and is prone to over-stretching. Cotton, linen, and silk sit around minus 5 to 0 percent. Always swatch to confirm. Q: Should I block a swatch first? A: Yes. Knit a generous swatch, measure it dry, block it the way you will block the finished piece, then measure again. The percent change is your most accurate growth figure to enter here, far better than the fibre averages. Q: Does negative growth make sense? A: Yes. Cotton and some plant fibres can relax tighter or shrink slightly after a wash, giving a negative percentage. Entering a negative number tells the calculator to compute a smaller blocked dimension than the dry measurement. Q: Will the piece stay at the blocked size? A: Untreated wool holds its blocked shape well. Superwash and slippery fibres tend to relax and grow further with wear and washing, so block them a little smaller than the target to leave room for creep. #### Knitting Sock Heel Turn Calculator URL: https://geratools.com/knitting-sock-heel-turn-calculator Enter your stitch gauge and foot circumference to compute cast-on stitches, heel-flap stitch and row counts, heel-turn math, and gusset pickup counts for both flap-and-gusset and short-row sock heels. For sock knitters. How to use: 1. Enter your gauge: Type stitches per inch (or per 10 cm) from your gauge swatch in the same yarn and needles you will use for the sock. 2. Enter foot circumference: Measure around the ball of the foot and enter that number, then choose a negative-ease percentage so the sock hugs the foot. 3. Read the heel math: The tool gives total cast-on, heel stitches, heel-flap row count, the turn-the-heel decrease math, and the gusset pickup count, for both heel styles. FAQ: Q: How many stitches go on the heel flap? A: A standard flap uses half the total sock stitches. If you cast on 64, the heel flap is worked over 32 stitches while the other 32 wait on the instep needles. This calculator splits your total automatically. Q: How long should the heel flap be? A: Work the flap until it is square — the same number of rows as there are heel stitches. With a slip-stitch pattern that slips every other row, this is typically the heel stitch count in rows, which the tool reports. Q: How does turning the heel work? A: Turning the heel uses short rows to cup the heel. You work to the centre, decrease, turn, and repeat, leaving roughly the centre third of the heel stitches plus the worked corners. The tool estimates the centre count and remaining stitches after the turn. Q: How many stitches do I pick up for the gusset? A: Pick up about one stitch per two rows along each side of the flap, which usually equals half the flap row count per side. The tool sums both sides plus the heel-turn stitches so you can check your needle counts before decreasing the gusset back to the original total. Q: What about a short-row heel? A: A short-row heel has no flap or gusset. It works over half the sock stitches and divides them into thirds: the centre third stays live while the outer thirds are wrapped and turned. The tool shows the centre and wrap stitch counts for the short-row method too. #### Masonry Lintel Load Calculator URL: https://geratools.com/masonry-lintel-calculator Computes the load on a masonry lintel over an opening using the 45-degree triangular arching assumption from NCMA TEK 12-3. Enter opening span, masonry unit weight, and wall height above the opening to get the triangular masonry load plus any superimposed uniform load, with the resulting design moment. How to use: 1. Enter the opening span: Type the clear span of the opening in feet. The bearing length is added automatically to give the effective span used for the moment. 2. Set masonry weight and height: Enter the weight of the masonry wall per square foot and the height of wall above the opening, so the tool can size the 45-degree load triangle. 3. Add any superimposed load: Optionally add a uniform load from floors or roof bearing on the wall above. The tool sums everything and reports the maximum bending moment. FAQ: Q: What is the 45-degree arching assumption? A: Masonry above an opening tends to bridge the gap by arching, so only the wall inside a 45-degree triangle directly over the opening actually loads the lintel. NCMA TEK 12-3 uses this triangle, with a height equal to half the opening span, as the design masonry load. Q: When does the full triangle apply? A: The full 45-degree triangle applies only when the wall extends at least half the span in height above the opening. If the wall is shorter, the loaded area is a trapezoid capped at the actual wall height, which the tool handles automatically. Q: How is the design moment found? A: The triangular masonry load is converted to an equivalent uniform load and combined with any superimposed uniform load. The maximum simple-span moment is then w*L^2/8 using the effective span (clear span plus bearing). This is the demand the lintel section must resist. Q: Does this size the lintel itself? A: No. It gives you the load and the bending moment demand. You then pick a precast concrete lintel, a steel angle, or a reinforced bond-beam lintel whose published moment capacity exceeds the demand, including a check for shear and deflection. Q: What about concentrated loads near the opening? A: This tool models uniform and triangular masonry loads only. A concentrated load such as a beam reaction landing within the arching region adds directly to the lintel and must be handled separately by a structural engineer. #### PEX vs Copper Flow Rate Comparison Calculator URL: https://geratools.com/pex-vs-copper-flow-calculator Uses Hazen-Williams friction with PEX-A and PEX-B (C=150) versus Type L copper (C=130) and published inside diameters to compare maximum flow rate and pressure drop per 100 ft for the same nominal pipe size. Runs in your browser. How to use: 1. Pick the nominal size: Choose 1/2 in, 3/4 in or 1 in. The tool loads the published inside diameter for PEX (ASTM F876) and Type L copper at that size. 2. Set a velocity limit and a design flow: Enter a velocity limit (e.g. 5 ft/s cold, 8 ft/s hot) for the max-flow figure, and a design flow in GPM for the pressure-drop comparison. 3. Compare the three materials: Read maximum GPM at your velocity limit and pressure drop per 100 ft side by side, so you can decide whether to upsize PEX one step. FAQ: Q: Why does PEX flow less than copper of the same size? A: PEX has a thicker wall, so its inside diameter is meaningfully smaller than Type L copper at the same nominal size — 0.475 in versus 0.545 in for 1/2 in. Flow area scales with the diameter squared, so even though PEX is smoother, the smaller bore usually wins and PEX carries less flow at the same pressure drop. Q: Is there a flow difference between PEX-A and PEX-B? A: Hydraulically they are nearly identical: both have the same ASTM F876 inside diameter and the same smooth-bore Hazen-Williams C of 150. PEX-A's expansion fittings keep the full bore at joints, while PEX-B insert fittings restrict it slightly, so PEX-A has a small real-world edge at the connections rather than in the straight run. Q: What Hazen-Williams C values does this use? A: It uses C=150 for both PEX types (very smooth plastic) and C=130 for Type L copper, which reflects mild interior aging. These are standard plumbing design values; new copper can be treated as C=140-150 if you want a best-case figure. Q: What velocity limit should I enter? A: A common guideline is 5 ft/s for cold water and 8 ft/s for hot, because higher velocities in copper accelerate erosion-corrosion and cause noise. PEX tolerates higher velocity but the same comfort and noise limits usually apply. Q: Should I upsize PEX by one step? A: Often yes for long trunk lines or pressure-sensitive fixtures. Running 3/4 in PEX where you would have used 1/2 in copper recovers the lost bore and keeps velocity and pressure drop in check. For short branch runs to a single fixture the difference is usually negligible. #### Pipe Insulation Heat Loss Calculator URL: https://geratools.com/pipe-insulation-heat-loss-calculator Applies the cylindrical radial-conduction formula in series with the outside air film, using thermal conductivities for fiberglass, foam rubber, mineral wool, and polyiso, to compute heat loss per linear foot for bare and insulated pipe at given fluid and ambient temperatures. Runs in your browser. How to use: 1. Enter pipe size and insulation: Select the nominal pipe size, the insulation material, and the insulation thickness in inches. Enter 0 thickness to model a bare pipe. 2. Set the temperatures: Enter the fluid temperature inside the pipe, the surrounding ambient air temperature, and the pipe run length. 3. Read heat loss per foot: The tool reports heat loss per linear foot for both bare and insulated pipe, the percentage reduction, and the total over the run. FAQ: Q: What formula does this use? A: It models steady-state radial conduction through the cylindrical insulation shell, R = ln(r2/r1) / (2πk), in series with the outside air film resistance, R = 1 / (h × 2πr2). Heat loss per foot equals the temperature difference divided by the sum of those two resistances. Q: Why does the first inch of insulation matter most? A: The insulation resistance grows with the natural log of the radius ratio, which increases slowly. Going from bare to one inch is a huge jump, but going from one inch to two adds far less, so most of the savings come from that first layer. Q: What conductivity values are used? A: Approximate design values in BTU·in per hr·ft²·F: fiberglass 0.25, foam rubber or elastomeric 0.27, mineral wool 0.26, and polyiso 0.20. Conductivity rises with temperature, so verify k at your mean insulation temperature for very hot or chilled service. Q: Does this work for chilled water pipes? A: Yes. If the fluid is colder than the ambient air, the temperature difference is negative and the pipe gains heat instead of losing it. The magnitude is the same calculation; the tool reports the absolute heat flow either way. For chilled lines also check the surface stays above the dew point to avoid condensation. Q: What air film coefficient should I use? A: Still indoor air gives an outside film coefficient around 1.5 to 1.8 BTU per hr·ft²·F, which is the default range. A draft or outdoor wind raises it, which slightly increases bare-pipe loss but barely affects a well-insulated pipe because the insulation dominates. #### Water Supply Pipe Sizing Calculator (Hunter's Curve / WSFU) URL: https://geratools.com/pipe-sizing-calculator-water Converts plumbing fixtures to Water Supply Fixture Units per IPC Table 604.3, looks up peak demand from Hunter's Curve, and returns the minimum copper pipe diameter that keeps velocity at or below 8 ft/s. For plumbers and mechanical contractors. Runs in your browser. How to use: 1. Count the fixtures: Enter how many of each fixture the branch or building main serves; each carries a Water Supply Fixture Unit value from IPC Table 604.3. 2. Set the velocity limit: Keep the default 8 ft/s velocity limit unless your local code or design standard calls for a lower value. 3. Read the pipe size: The tool totals WSFU, looks up peak demand on Hunter's Curve, and returns the smallest copper pipe that carries that flow within the velocity limit. FAQ: Q: What is a Water Supply Fixture Unit? A: A WSFU is a dimensionless weighting that represents a fixture's probable water demand, accounting for both flow rate and how often it is used. IPC Table 604.3 assigns a WSFU value to each fixture so designers can add them up across a system. Q: What is Hunter's Curve? A: Hunter's Curve is a statistical relationship, developed by Roy Hunter, that converts total fixture units into a probable peak simultaneous demand in gallons per minute. Because not all fixtures run at once, demand rises far more slowly than the raw fixture-unit total. Q: Why limit velocity to 8 feet per second? A: The IPC limits water velocity to reduce noise, erosion of pipe walls, and water hammer. The tool sizes pipe so the calculated peak flow stays at or below the velocity you set, defaulting to the common 8 ft/s ceiling. Q: Does this replace a full hydraulic design? A: It gives a sound minimum size by demand and velocity, but a complete design also checks pressure loss against available supply pressure over the run length, plus fixture minimum flow pressures. Use it as the demand-and-velocity step of a fuller calculation. Q: Are flush-tank and flushometer toilets different? A: Yes. A flushometer valve closet draws far more instantaneous flow than a flush-tank closet, so it carries a much higher WSFU value. The tool lists both so you can pick the type actually installed. #### Plumbing Fitting Angle & Rolling Offset Calculator URL: https://geratools.com/plumbing-pipe-offset-angle-calculator Takes the horizontal roll and vertical rise of a pipe run plus the fitting angle, such as 45 or 22.5 degrees, and solves the true offset, the diagonal travel length, and the fitting-to-fitting measurement using 3D pipe-offset trigonometry. Runs entirely in your browser. How to use: 1. Enter the roll and rise: Measure how far the pipe must move sideways (the roll) and how far up or down (the rise) between the two parallel runs, in inches. 2. Choose the fitting angle: Select the angle of the fittings you will use, commonly 45 or 22.5 degrees, which sets the geometry of the diagonal piece. 3. Read the travel and cut: The tool gives the true offset, the diagonal travel along the fitting centers, and the cut length after subtracting fitting take-out if entered. FAQ: Q: What is a rolling offset? A: A rolling offset is when a pipe must shift both sideways and up or down at the same time, so the connecting piece runs diagonally in three dimensions. The true offset is the straight-line distance combining the horizontal roll and the vertical rise. Q: How is the travel length calculated? A: First the true offset is the square root of roll squared plus rise squared. Then the travel, the length of the diagonal pipe between fitting centers, equals the true offset divided by the sine of the fitting angle. For a 45 degree fitting that is the true offset times 1.414. Q: What is fitting take-out? A: Take-out is the laying length a fitting consumes, measured from the center of the fitting to the face where the pipe seats. The center-to-center travel must be reduced by the take-out of both fittings to get the actual pipe cut length. Q: Why use 22.5 degree fittings instead of 45? A: Shallower angles like 22.5 degrees create a longer, gentler diagonal that improves drainage flow and reduces turbulence, at the cost of more travel length and space. Fitting angle choice balances flow, space, and the available fitting inventory. Q: Does the order of roll and rise matter? A: No. The true offset combines them with the Pythagorean theorem, which is symmetric, so swapping roll and rise gives the same true offset and travel. The spread, or the individual horizontal and vertical legs, will differ in orientation but not in magnitude. #### Plumbing Rough-In Dimensions Reference URL: https://geratools.com/plumbing-rough-in-dimensions-calculator A searchable reference of standard plumbing rough-in dimensions including drain center-to-wall, supply height above finished floor, and valve offsets for common fixtures, cross-referenced to typical IPC and UPC practice. Runs entirely in your browser. How to use: 1. Pick a fixture: Select the fixture you are roughing in, such as a toilet, lavatory, kitchen sink, tub, shower, or water heater. 2. Read the standard dimensions: The tool lists the typical drain center, supply heights above finished floor, and valve offsets used in residential construction. 3. Confirm against the spec sheet: Use the standard figures as a starting point, then verify against the manufacturer rough-in sheet and your local code before cutting in. FAQ: Q: What does a 12-inch toilet rough-in mean? A: The rough-in is the distance from the finished wall to the center of the toilet flange waste pipe. Twelve inches is the most common, but 10-inch and 14-inch rough-ins exist for older or unusual layouts. Measure to the bolt caps, not the baseboard. Q: How high should lavatory supplies be roughed in? A: Bathroom lavatory hot and cold supplies are typically set about 20 to 22 inches above the finished floor, with the drain centered near 18 to 19 inches. Spacing between hot and cold is usually 8 inches on center. Q: What is the standard shower valve height? A: A shower-only valve is commonly set 38 to 48 inches above the finished floor, while a tub-and-shower valve sits lower at about 28 inches. The shower head arm typically roughs in at 78 inches. Adjust for tall users. Q: Do these dimensions satisfy ADA? A: No. These are standard residential figures. ADA and accessible fixtures have their own mounting heights, clearances, and reach ranges that override these values. Use the accessibility standard when the project requires it. Q: Why verify against the manufacturer sheet? A: Every fixture model has a specific rough-in drawing showing exact waste and supply locations. Wall-hung toilets, vessel sinks, and freestanding tubs vary widely. The standards here are a planning reference, not a substitute for the model spec sheet. #### Rebar Spacing & Lap Splice Calculator URL: https://geratools.com/rebar-spacing-calculator Calculate the number of rebars and centre-to-centre spacing across a slab or wall width with edge cover, and compute the ACI 318 tension lap-splice length (Class A or B) from bar diameter, concrete f'c, and steel fy. Outputs computed and code-minimum values. How to use: 1. Enter member width and cover: Type the slab or wall width and the clear cover from each edge to the first bar. 2. Set bar count or target spacing: Enter how many bars you want, and the tool finds the centre-to-centre spacing across the width. 3. Read spacing and lap length: The tool shows the spacing plus the ACI 318 tension lap-splice length for the chosen bar size, concrete strength, and steel grade. FAQ: Q: How is bar spacing across a width calculated? A: The first and last bars sit one cover distance from each edge, so the usable spread is width minus twice the cover minus one bar diameter. Dividing that spread by the number of gaps (bar count minus one) gives the centre-to-centre spacing. Q: What is a lap splice and how long must it be? A: A lap splice overlaps two bars so force transfers between them. ACI 318 sets the tension lap as a multiple of the development length: Class A is 1.0 times and Class B is 1.3 times the development length, with a 12 inch minimum. Q: Which development length formula is used? A: The simplified ACI 318 expression for tension development length of a deformed bar: ld = (fy x psi factors x db) / (25 x sqrt(f'c)) in inches, with f'c and fy in psi. The tool applies typical factors for uncoated bottom bars and shows the result. Q: When do I use Class A versus Class B splices? A: Class A applies when the area of steel provided is at least twice that required and no more than half the bars are spliced in the lap zone. Otherwise use the longer Class B splice. When in doubt, designers default to Class B. Q: Is this a substitute for a structural engineer? A: No. It gives planning estimates using simplified ACI 318 expressions. Final spacing and splice details must come from the project's structural drawings and a licensed engineer, accounting for the full set of code modification factors. #### Refrigerant Oil Charge Calculator (Line Set Extension) URL: https://geratools.com/refrigerant-oil-charge-calculator Computes the additional POE or mineral oil charge needed when a refrigerant line set exceeds the factory-rated length, using the manufacturer's oz-per-foot rate. For HVAC technicians installing mini-splits and refrigeration systems with long line runs. Runs in your browser. How to use: 1. Enter the line set lengths: Type the total installed line set length and the factory-rated or pre-charged length, both in feet. 2. Enter the oil rate and type: Type the manufacturer's oil addition rate in ounces per additional foot, and choose POE or mineral oil to match the compressor. 3. Read the additional oil: The tool multiplies the feet beyond the rated length by the per-foot rate to give the ounces of oil to add to the system. FAQ: Q: Why do long line sets need extra oil? A: Oil circulates with the refrigerant and some of it clings to the inside of the tubing. A longer line set holds more refrigerant and coats more pipe wall, so it traps more oil away from the compressor. Adding oil keeps the compressor sump at a safe level. Q: How much oil should I add per extra foot? A: It depends on the model, but a common figure is about 0.5 to 0.6 ounces of oil per additional foot of liquid line beyond the rated length. Always confirm the exact rate on the unit's installation manual before charging. Q: Should I use POE or mineral oil? A: Use whatever oil the compressor is already charged with. Most modern HFC and HFO systems use POE (polyolester) oil, while older R-22 equipment uses mineral oil. Mixing incompatible oils can cause sludging and compressor failure. Q: What happens if I do not add the oil? A: The compressor can run oil-starved, leading to overheating, accelerated bearing wear, and eventual mechanical failure. On a long line run that exceeds the rated length, topping up oil is essential, not optional. Q: Does line set elevation change the oil charge? A: Elevation does not change the volume of oil to add, but a large vertical rise affects oil return and may require oil traps on the suction riser. Follow the manufacturer's guidance on trap spacing for tall lifts. #### Residential Mechanical Ventilation Calculator (ASHRAE 62.2) URL: https://geratools.com/residential-ventilation-cfm-calculator Enter conditioned floor area and bedroom count to compute the whole-house mechanical ventilation rate from ASHRAE 62.2 Equation 4.1a, apply an optional infiltration credit, and get a recommended ERV or HRV size and control type. For HVAC contractors on tight new construction. Runs in your browser. How to use: 1. Enter floor area and bedrooms: Type the conditioned floor area in square feet and the number of bedrooms, which the standard uses as a proxy for occupancy. 2. Select the standard edition: Choose ASHRAE 62.2-2022 with the current 0.03 coefficient or the legacy 2010 edition with 0.01, and optionally add an infiltration credit for leaky homes. 3. Read the required airflow and unit size: The tool shows the whole-house ventilation rate, the required fan airflow after any credit, and a recommended ERV or HRV nominal size and control strategy. FAQ: Q: What is ASHRAE 62.2 Equation 4.1a? A: It defines the whole-house mechanical ventilation rate as a coefficient times floor area plus 7.5 cfm times the number of bedrooms plus one. The bedroom term is a proxy for occupancy, and the area term accounts for emissions from the building and its contents. Q: Why are there two coefficients, 0.03 and 0.01? A: The current ASHRAE 62.2-2022 edition uses 0.03 cfm per square foot, while the older 2010 edition used 0.01. The standard increased the area term over time, so the tool lets you select the edition your jurisdiction has adopted to get the matching rate. Q: What is the infiltration credit? A: A leaky home already gets some fresh air through its cracks, so the standard lets you subtract a measured infiltration rate from the required fan airflow. Tight new construction has almost no infiltration, so the credit is near zero and the fan must supply the full rate. Q: Does this replace local exhaust fans? A: No. The whole-house rate is separate from and in addition to local exhaust in kitchens and bathrooms, which 62.2 also requires. You need both: continuous or intermittent whole-house ventilation plus spot exhaust at the moisture and odor sources. Q: Should the system be continuous or intermittent? A: A continuous low-speed ERV or HRV is the simplest path to compliance and stays quiet. Intermittent operation is allowed if the higher airflow multiplied by the fractional run time and divided by the effectiveness still meets the whole-house rate, but it requires careful controls. #### Resin Print Support Angle Guide URL: https://geratools.com/resin-print-support-angle Find the maximum unsupported overhang angle for your resin and layer height on MSLA/SLA printers, with the per-layer overhang step and recommended support tip density for shallower angles. Built for resin 3D printing hobbyists. Runs 100% in your browser. How to use: 1. Enter the overhang angle: Measure the steepest surface in question as the angle from horizontal — 90° is a vertical wall, 0° is flat to the plate. 2. Set layer height and resin: Type your layer height in microns and choose your resin's toughness class. 3. Read the verdict: The tool says whether the surface is self-supporting and, if not, recommends support tip size and spacing. FAQ: Q: What overhang angle can resin print without supports? A: On MSLA printers, surfaces steeper than about 30–35° from horizontal usually print without supports in standard resin. Tougher resins and thinner layers let you go shallower, down toward 20–25°. Q: How is the per-layer overhang step calculated? A: The horizontal step a new layer extends past the one below equals the layer height divided by the tangent of the angle from horizontal. Larger steps put more peel and gravity stress on each new layer. Q: Why do tougher resins handle shallower overhangs? A: Tough and ABS-like resins resist the peel force of the FEP separation and the weight of unsupported material better than brittle standard resins, so they hold thinner self-supporting overhangs without tearing. Q: Does layer height change the safe angle? A: Yes. Thinner layers create a smaller per-layer step at the same angle, so a 25 µm layer can self-support a shallower overhang than a 100 µm layer on the same model. Q: Should I still angle my whole model? A: Yes. Tilting the model 30–45° avoids large flat layers that create big suction forces, reduces aliasing, and lets supports attach to less visible areas. Always run an island check in your slicer too. #### Wood Shear Wall Capacity Calculator URL: https://geratools.com/shear-wall-capacity-calculator Looks up the nominal unit shear capacity in plf from AWC SDPWS Table 4.3A for blocked plywood or OSB shear walls based on panel thickness, nail size, and edge nail spacing. Converts to ASD or LRFD design values, multiplies by wall length, and checks against the applied story shear. Runs in your browser. How to use: 1. Pick the panel and nailing: Choose the panel thickness and nail size combination, then select the edge nail spacing of 6, 4, 3, or 2 inches on center. 2. Choose method and length: Select ASD or LRFD design and enter the shear wall length in feet. 3. Read the capacity: The tool returns the nominal unit shear, the design value, the total wall capacity, and whether it resists the applied story shear. FAQ: Q: Where do the unit shear values come from? A: They are the nominal unit shear capacities tabulated in AWC SDPWS Table 4.3A for blocked wood structural panel shear walls on Douglas-Fir-Larch or Southern Pine framing. Each value depends on panel thickness, nail size, and edge nail spacing. Q: How do I convert nominal shear to a design value? A: For allowable stress design divide the nominal unit shear by 2.0, and for load and resistance factor design multiply by the resistance factor of 0.80. The tool applies whichever method you select before computing wall capacity. Q: Why does tighter nail spacing add so much capacity? A: Edge nails transfer shear between the panel and the framing. Closer spacing at panel edges means more fasteners sharing the load, so going from 6 inch to 2 inch spacing can more than double the unit shear capacity. Q: Is panel nailing the only thing that limits a shear wall? A: No. Hold-down anchors that resist overturning, the wall aspect ratio of height to length, and the sill-plate attachment to the foundation all cap real capacity. This tool covers the panel unit shear; verify the other limits separately. Q: Does this apply to unblocked walls? A: The stored values are for blocked walls, where panel edges land on framing or blocking. Unblocked walls have lower capacity and require separate adjustment factors, so use a blocked configuration for these numbers to apply. #### Soap Lye (Saponification) Calculator URL: https://geratools.com/soap-lye-saponification-calculator Enter oil types and weights to compute the NaOH or KOH lye amount using published saponification values, with a configurable superfat and water percentage. For cold-process and hot-process soap makers. How to use: 1. Choose lye type and superfat: Pick NaOH for solid bars or KOH for liquid soap, then set your superfat percentage, usually around 5 percent. 2. Add your oils by weight: Add each oil or butter in your recipe with its weight in grams; the tool applies the correct saponification value to each. 3. Read the lye and water amounts: The tool totals the lye needed across all oils, reduces it for superfat, and gives the water amount and lye concentration. FAQ: Q: What is a saponification (SAP) value? A: A SAP value is the amount of lye needed to fully saponify one gram of a specific oil. Each oil has its own value because of its fatty-acid makeup. The tool multiplies each oil's weight by its SAP value and sums the results to get total lye. Q: What is superfat and why does it matter? A: Superfat is the percentage of oils left unsaponified on purpose, by using slightly less lye than the full amount. It makes the finished soap gentler and guarantees no leftover caustic lye. Five percent is a common, safe default for bar soap. Q: What is the difference between NaOH and KOH? A: NaOH (sodium hydroxide) makes solid bar soap; KOH (potassium hydroxide) makes liquid and soft soap. KOH has a higher molar mass, so it takes about 1.4 times as much by weight to saponify the same oils. The tool converts automatically based on your choice. Q: Why does the calculator ask for water as a percent of oils? A: Water dissolves the lye so it can react with the oils, then evaporates as the soap cures. A common starting point is water at about 38 percent of the oil weight. The tool also shows the resulting lye concentration so you can adjust to your method. Q: Is this calculator safe to make soap from directly? A: Use it as a planning aid and always verify your recipe against a second trusted lye calculator before mixing. Lye is caustic: add lye to water, never water to lye, wear gloves and eye protection, and work in a ventilated space. #### Off-Grid Solar System Calculator URL: https://geratools.com/solar-power-system-calculator Enter daily energy use in watt-hours, peak sun hours, panel wattage and battery voltage to compute array size, battery bank capacity in amp-hours, and minimum MPPT charge controller amperage for an off-grid or van-life system. How to use: 1. Enter your daily energy use: Add up the watt-hours your loads use per day from an energy audit, then enter that total along with your local peak sun hours. 2. Pick a panel and battery voltage: Enter the wattage of the panel you plan to buy and choose your system voltage (12, 24 or 48 V). Higher voltage means lower current and thinner wiring. 3. Read the sizing results: The tool returns the number of panels, battery bank amp-hours for your days of autonomy and depth of discharge, and the minimum charge controller amperage. FAQ: Q: How many solar panels do I need for off-grid? A: Divide your daily watt-hour use by peak sun hours, then multiply by about 1.3 to cover wiring, heat and conversion losses. Divide that wattage by your panel rating and round up. For 2000 Wh/day at 4.5 sun hours you need roughly 578 W, or two 400 W panels. Q: What does depth of discharge mean for battery sizing? A: Depth of discharge is how far you safely drain the bank. Lead-acid is usually limited to 50%, lithium to 80–100%. A lower limit means you must install more capacity to deliver the same usable energy, so the bank amp-hours rise accordingly. Q: How is the charge controller amperage calculated? A: For an MPPT controller the output current equals array watts divided by battery voltage. We add a 1.25 continuous-current safety margin per electrical code, so a 800 W array on a 24 V bank needs at least a 42 A controller. Q: Why does the array get oversized by 30%? A: Real systems lose energy to wiring resistance, dust, high panel temperature, and charge-controller and inverter inefficiency. Oversizing the panel wattage by about 30% ensures the batteries still fully recharge on an average day. Q: Does days of autonomy matter? A: Yes. Days of autonomy is how long the bank runs your loads with no sun. Two days is common; cloudier climates use three or more. More autonomy multiplies the required battery capacity directly. #### HVAC Static Pressure Drop Calculator URL: https://geratools.com/static-pressure-calculator Add up the pressure drop of every component in an air-handling path — filter, indoor coil, supply duct, return duct, registers and grilles — to get total external static pressure in inches WC, and compare it against the blower's rated maximum. Built for HVAC airflow checks. Runs in your browser. How to use: 1. Enter component pressure drops: Type the measured or rated pressure drop in inches of water column for the filter, indoor coil, supply duct, return duct, and registers and grilles. 2. Enter the blower rating: Enter the blower's rated maximum total external static pressure, usually 0.5 inches WC for residential equipment, to compare against. 3. Read the total: The tool sums every drop into total external static pressure and tells you whether it is within the blower rating or excessive. FAQ: Q: What is total external static pressure? A: Total external static pressure, or TESP, is the sum of all resistance the blower must overcome outside the cabinet — filter, coil, supply and return ductwork, and grilles. It is the single most important field measurement of whether an air handler can move its rated airflow. Q: Why does high static pressure matter? A: Excessive static pressure reduces airflow below design, which causes poor comfort, frozen coils, short equipment life and high energy use. A blower rated for 0.5 inches WC that actually sees 0.9 inches will deliver far less than its rated CFM, starving the system. Q: Where do the component values come from? A: You can measure each drop with a manometer across the component, or use rated values from the manufacturer's data — for example a clean pleated filter near 0.1 inches WC and a wet coil near 0.3 inches WC. Dirty filters and coils raise these numbers substantially. Q: What is a normal total static pressure? A: Most residential blowers are rated for 0.5 inches WC total external static pressure. Readings of 0.6 to 0.8 are common but indicate restricted systems; anything well above the rating means undersized ductwork, a clogged filter or coil, or closed dampers that must be addressed. Q: How do I lower static pressure that is too high? A: Start with the easy wins: replace a dirty filter, clean the coil, and open closed registers and dampers. Persistent high static usually points to undersized return or supply ducts, which require adding return area or upsizing trunk lines to bring airflow back to design. #### Roof Drain & Stormwater Pipe Sizing Calculator URL: https://geratools.com/stormwater-roof-drain-sizing Applies IPC 1106 and ASCE 7 design rainfall (bundled 100-year 1-hour intensity by US state) to compute required drainage flow in GPM, then sizes the vertical leader and horizontal storm drain from IPC Tables 1106.2 and 1106.3. How to use: 1. Enter roof area: Type the horizontal projected roof area draining to the leader in square feet, including any walls that shed water onto the roof. 2. Set rainfall: Pick the state for a 100-year 1-hour design intensity, or override with the exact in/hr value from NOAA Atlas 14 for your site. 3. Read the pipe sizes: The tool returns required flow in GPM and the minimum vertical leader and horizontal storm-drain diameters from the IPC tables. FAQ: Q: How is required flow calculated from roof area? A: One inch of rain per hour over one square foot is about 0.0104 gallons per minute, so the tool multiplies roof area by rainfall intensity by 0.0104 to get design flow in GPM. A 5,000 sq ft roof at 4 in/hr therefore produces roughly 208 GPM. Q: Where do the pipe sizes come from? A: Vertical leaders and conductors are sized from IPC Table 1106.2 and horizontal storm drains from Table 1106.3 at 1/8 inch per foot slope. The tables are normalized to a 1 in/hr rainfall, so the tool scales the tributary area by the actual intensity before selecting a size. Q: What rainfall intensity should I use? A: The IPC requires the 100-year, 1-hour rainfall rate for the building location. The bundled state values are representative; for a permit you should read the exact intensity from the IPC rainfall map or NOAA Atlas 14 for the specific site, which the override field lets you enter directly. Q: Do I need a secondary drainage system? A: Yes. IPC Section 1107 requires a secondary (overflow) roof-drainage system sized for the same design rainfall, with its outlet positioned above the roof so a blockage of the primary system becomes visible. Size the overflow drains and scuppers separately to equal capacity. Q: Does vertical wall area count? A: It can. Where adjacent vertical walls drain onto the roof, a portion of that wall area is added to the horizontal roof area as tributary area per IPC commentary. Add it to the roof-area input so the leader and drain are not undersized. #### Commercial Plumbing Fixture Count Calculator (IPC 403) URL: https://geratools.com/urinal-fixture-unit-calculator Applies IPC Table 403.1 minimum fixture ratios by occupancy classification and occupant load to return required water closets, urinals, lavatories, and service sinks for commercial and institutional buildings during permit plan check. How to use: 1. Pick the occupancy: Select the building's occupancy classification — business, mercantile, assembly, educational, or factory — so the correct IPC ratio applies. 2. Enter the occupant load: Type the total occupant load from the egress calculation and the male share (default 50%). The tool splits the load by gender. 3. Read the required counts: The table returns minimum water closets, urinals, lavatories, and service sinks, applying the 67% urinal substitution allowance if enabled. FAQ: Q: Where do these fixture ratios come from? A: They are encoded from IPC Table 403.1, which lists the minimum number of plumbing fixtures as a ratio of persons per fixture for each occupancy group. Office (business) use, for example, requires one water closet per 25 persons for the first 50, then one per 50 thereafter. Q: Can urinals really replace water closets? A: Yes, within limits. IPC Section 419.2 allows urinals to be substituted for up to 67% of the required water closets in men's facilities. The calculator caps the substitution at that ratio when the option is enabled and never drops the men's water closet count below one. Q: How is the occupant load split between men and women? A: The IPC assumes a 50/50 split unless the design provides a documented basis for a different ratio. You can override the male share field if your occupancy skews one way, and the tool re-divides the load accordingly. Q: Does this include accessible fixtures or drinking fountains? A: No. The minimum counts are total fixtures; at least one of each must be accessible per ICC A117.1, and drinking fountains are required separately under IPC Section 410. Treat those as additional requirements layered on top of these counts. Q: Is this output sufficient for a permit submittal? A: It is a reliable planning aid, but the authority having jurisdiction makes the final determination. Local amendments to the IPC are common, so confirm the adopted code edition and any state modifications before submitting your fixture schedule. #### Window Rough Opening Calculator URL: https://geratools.com/window-rough-opening-calculator Converts a window or door unit size to the rough opening it needs by adding standard shim clearance. Windows add about 1/2 inch per side and 1/2 inch at the head; doors add roughly 2 inches in width and 2.5 inches in height for the jamb and threshold. Outputs RO width and height for framing layout. How to use: 1. Choose window or door: Pick whether you are framing a window or a door, since the standard clearances differ between the two. 2. Enter the unit dimensions: Type the actual unit width and height of the window or door, in inches. This is the manufacturer's unit size, not the glass or panel size. 3. Read the rough opening: The tool adds the standard shim and jamb clearance and returns the rough opening width and height to mark out between your jack studs and header. FAQ: Q: How much clearance does a window need? A: The common rule is 1/2 inch of shim space on each side and 1/2 inch at the head, so the rough opening is the window unit width plus 1 inch and the unit height plus 1/2 inch. Always confirm against the manufacturer's installation sheet, which sometimes calls for more. Q: Why do doors need more clearance than windows? A: Pre-hung doors include a jamb and need room to plumb and shim it, plus clearance at the threshold. A common allowance is the door slab width plus 2 inches and the height plus about 2.5 inches, giving room for the jamb, shims, and floor finish. Q: Is the unit size the same as the glass size? A: No. The unit size is the outside frame dimension of the whole window or door. The glass or panel inside is smaller. Always size the rough opening from the unit dimension, never from the glass or the bare slab. Q: What is the difference between RO and unit size? A: Unit size is what you order. Rough opening (RO) is the framed hole between studs and header that the unit drops into, made deliberately larger so you can shim the unit plumb, level, and square. This tool converts one to the other. Q: Should I always trust the calculator over the spec sheet? A: No. These are industry-standard defaults that suit most residential units, but manufacturers vary. When you have the installation instructions for your specific product, use their stated rough opening — it overrides any general rule. #### Paint Calculator URL: https://geratools.com/paint-calculator Free paint calculator that works out how many litres or gallons you need for a room from wall dimensions, coats and door/window deductions. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your room: Choose metric or imperial units, then type the room length, width and wall height. 2. Deduct openings and pick coats: Set how many doors and windows to subtract, the number of coats and your paint's coverage rate. 3. Read the total: The calculator shows the litres or gallons of paint to buy and the paintable wall area. FAQ: Q: How does it estimate paint coverage? A: It calculates wall area as room perimeter times height, subtracts a standard area for each door and window, multiplies by the number of coats, then divides by your paint's coverage rate (litres per square metre or gallons per square foot). Q: What coverage rate should I use? A: Most emulsion covers roughly 10–12 m² per litre (about 350–400 ft² per gallon) per coat. Check your tin, since primers and textured surfaces cover less. The default is 11 m²/litre. Q: How much area does each door and window deduct? A: In metric the tool subtracts 1.9 m² per door and 1.4 m² per window; in imperial it subtracts 21 ft² per door and 15 ft² per window. These are typical opening sizes and keep the estimate from overbuying. Q: Why does the calculator use perimeter times height? A: A room's four walls together have an area equal to the perimeter (2 × (length + width)) multiplied by the wall height. This counts all four walls in one step before openings are deducted. Q: How many coats of paint do I need? A: Two coats is standard for good coverage on most walls. Use one coat for a light refresh over a similar colour, and three when going from dark to light or onto fresh plaster. Q: Should I round up when buying paint? A: Yes. Buy whole tins covering at least the litres or gallons shown, and keep a little extra for touch-ups. The result is the minimum volume needed for the area and coats you entered. Q: Is my room data sent anywhere? A: No. Every calculation runs entirely in your browser and nothing is uploaded to any server. #### Flooring Calculator URL: https://geratools.com/flooring-calculator Free flooring calculator that works out how many packs of laminate, vinyl or wood flooring you need from the room size, pack coverage and a waste allowance. Runs entirely in your browser — nothing is uploaded. How to use: 1. Measure the room: Choose your units and enter the room length and width to get the floor area. 2. Enter pack coverage and waste: Type how much area one pack of flooring covers and a waste percentage for cuts. 3. Read the pack count: The calculator returns the number of whole packs to buy, including the waste allowance. FAQ: Q: How does the flooring calculator work? A: It multiplies room length by width to get the floor area, adds your waste percentage, then divides by the coverage per pack and rounds up to whole packs. Q: How much waste should I add for flooring? A: An 8–10% allowance is normal for straight rooms; use up to 15% for diagonal layouts, herringbone patterns, or rooms with lots of corners and offcuts. The default is 8%. Q: Where do I find the coverage per pack? A: It is printed on the flooring box, usually in square metres or square feet — for example "2.2 m² per pack". Enter that figure so the calculator divides your room area by the right amount. Q: Should I keep a spare pack? A: Yes. It is good practice to keep one unopened pack from the same batch for future repairs, because dye lots vary between production runs and an exact match later can be hard to find. Q: Is anything I enter uploaded? A: No. All calculations happen entirely in your browser and nothing is sent to any server. #### Fence and Gate Calculator URL: https://geratools.com/fence-and-gate-calculator Free fence and gate calculator. Enter the run length, post spacing and gate widths to get posts, panels, rails, concrete bags and a full material cost — metric or imperial, all in your browser. How to use: 1. Pick metric or imperial: Choose metres or feet — your run length, post spacing and gate widths convert automatically when you switch. 2. Enter the run and spacing: Type the total fence run, the target post spacing (panel width) and how many rails each panel has. 3. Add your gates: Set the number of gates and the width of each opening; the tool subtracts gate openings from the fenced length and adds a hanging post per gate. 4. Add unit prices: Enter the price per post, panel, rail, gate and concrete bag to get a full material cost estimate with a per-metre rate. FAQ: Q: How many fence posts do I need for my run? A: Divide the fenced length (run minus gate openings) by your post spacing and round up to get the number of panel bays, then add one for the closing post. A straight run of N bays needs N+1 posts. This calculator does that automatically and adds an extra hanging post for every gate. Q: How is the number of panels calculated? A: One panel fills each bay between two posts. The tool divides the fenced length by your post spacing and rounds up so no gap is wider than your target, then applies your wastage percentage and rounds up to whole panels. Q: How many rails per fence panel should I use? A: Most timber panels use two rails for fences up to about 1.2 m and three rails for taller 1.8 m fences, with a fourth on heavy closeboard. Set the rails-per-panel field to match your panel type; total rails are bays multiplied by rails per panel. Q: How much concrete do I need per fence post? A: A common rule of thumb is one to two bags of fast-set post mix per post for a standard 1.8 m fence in firm ground, more for tall or exposed runs. Set the bags-per-post field to your own figure and the tool multiplies it by the total post count. Q: Does the calculator handle gates correctly? A: Yes. Each gate opening is subtracted from the run before panels are counted, so you never buy a panel for a gap a gate fills, and one extra hanging post is added per gate. Total gate width is capped at the run length so the maths stays sane. Q: What is not included in the cost estimate? A: The estimate covers posts, panels, rails, gates and concrete only. It excludes labour, post caps, gravel boards, capping rail, fixings, hinges, latches, delivery and tax. Treat the total as a materials baseline and add those extras for a full budget. #### Flooring Calculator (Multi-Room, with Cost) URL: https://geratools.com/flooring-calculator-pro Advanced flooring calculator: add multiple rooms, choose laminate, hardwood or vinyl, set pack or plank coverage and a waste allowance, then get the exact number of packs, leftover, underlay and total cost. Metric and imperial. Runs entirely in your browser. How to use: 1. Pick your units and flooring type: Switch between metric (m / m squared) and imperial (ft / ft squared), then choose laminate, hardwood or vinyl. The maths is identical across types — the labels just match what you are buying. 2. Add every room: Enter the length and width of each room. Add as many rooms as you need; the tool sums their areas so one order covers the whole job. 3. Set pack or plank coverage: Either type the coverage printed on the pack, or enter the plank length, width and planks per pack and let the tool work out the coverage for you. 4. Choose a waste allowance: Use a preset (7 percent straight, 10 percent standard, 15 percent diagonal, 20 percent herringbone) or type your own. Waste covers cuts, breakages and offcuts. 5. Add prices for a cost estimate: Enter price per pack (and optional underlay) to see material cost and the all-in total, plus how much surplus flooring you will be left with. FAQ: Q: How many packs of flooring do I need? A: Divide the total floor area (including waste) by the coverage of one pack, then round up to the next whole pack. For example, 30 square metres plus 10 percent waste is 33 square metres; at 2.22 square metres per pack that is 33 divided by 2.22 equals 14.9, rounded up to 15 packs. Q: How much waste should I allow for flooring? A: Allow about 5 to 10 percent for a simple straight lay in a rectangular room, 10 to 15 percent for rooms with alcoves, doorways or a diagonal lay, and up to 20 percent for herringbone or chevron patterns because they need far more cutting. Q: Does this work for laminate, hardwood and vinyl? A: Yes. The pack-and-waste maths is the same for all three. The flooring-type selector only changes the labels so the result matches the product you are buying. Vinyl and LVT are often sold in tiles or planks too, so use the plank mode if a pack lists plank dimensions. Q: Should I keep the leftover flooring? A: Keep at least one spare pack. Boards from the same batch are colour-matched, so a future repair after a spill or scratch will blend in. The calculator shows your exact leftover so you know how much you are keeping. Q: How do I work out coverage from plank dimensions? A: Multiply the plank length by its width to get the area of one plank, then multiply by the number of planks in a pack. A 1285 mm by 192 mm plank is about 0.247 square metres; nine of them give roughly 2.22 square metres per pack. Switch to plank mode and the tool does this for you. Q: Is my data sent anywhere? A: No. Every measurement and price stays in your browser and the result is computed locally. Your inputs are only saved to this browser so the form remembers them next time, and nothing is ever uploaded. #### Drywall Calculator URL: https://geratools.com/drywall-calculator Free drywall and plasterboard calculator. Enter your walls and ceilings, deduct doors and windows, pick a sheet size and it works out how many sheets, screws, joint compound, tape and the total material cost. Metric or imperial. Runs entirely in your browser. How to use: 1. List the walls and ceilings: Add a row for each surface with its width, height and how many identical surfaces there are. Use metres or feet — switch units at the top. 2. Deduct doors and windows: Add each opening with its width, height and count. The calculator subtracts their area from the surface total so you do not buy board you will cut away. 3. Choose a sheet size and wastage: Pick a US 4x8, UK 1200x2400 or custom sheet, set single or double boarding, and a wastage percentage for off-cuts and breakages. 4. Read the materials and cost: See sheets, screws, joint compound, tape and an optional priced breakdown. Buy whole units and keep a spare sheet. FAQ: Q: How many sheets of drywall do I need? A: Divide the net area you are boarding (gross surface area minus doors and windows) by the area of one sheet, then add a wastage allowance and round up to whole sheets. A UK 1200x2400 mm sheet covers 2.88 m2; a US 4x8 ft sheet covers about 2.97 m2. This calculator does that for every wall and ceiling you list at once. Q: How much wastage should I add for drywall? A: Ten percent is a sensible default for a simple room. Add more (15 to 20 percent) for rooms with lots of corners, sloped ceilings, small awkward spaces or an inexperienced installer, because off-cuts above doors and below windows rarely fit elsewhere. Q: How many screws per sheet of drywall? A: A common trade rule is roughly 28 to 32 screws per sheet for walls fixed to studs at 16 inch or 400 mm centres, and a few more for ceilings. This tool uses about 30 per sheet as a balanced average; tighter ceiling fixing schedules or metal framing can need more. Q: How much joint compound and tape will I use? A: As a rule of thumb you need about 0.5 kg of joint compound and 1.5 metres of joint tape per square metre of boarded area, covering taping, two filling coats and a skim. Textured finishes, level-5 finishes or wide bedding joints use more, so treat the figure as a starting estimate. Q: Does it work in feet and inches or only metric? A: Both. Switch the units selector to imperial to enter every measurement in feet (decimals such as 2.4 ft are fine), and all areas, tape lengths and sheet sizes are shown back in feet and square feet. Sheet presets include US 4x8 and 4x12 as well as UK metric boards. Q: Is my data sent anywhere? A: No. Every calculation runs in your browser using JavaScript. Nothing you type is uploaded, saved to a server or shared, so you can use it on private renovation budgets freely. #### 3D Print Time & Material Estimator URL: https://geratools.com/3d-print-time-estimator Free 3D print time estimator — enter model volume, infill percentage, layer height and print speed to get an estimated print duration, filament mass, material volume and cost. Works for FDM (PLA, PETG, ABS, ASA, TPU, Nylon) and resin (MSLA/LCD) printers. Runs entirely in your browser. How to use: 1. Export model volume and surface area from your slicer: Open your model in PrusaSlicer or Cura. In PrusaSlicer use Object > Model Info; in Cura open the Prepare tab and check Model information in the sidebar. Note the volume in cm³ and surface area in cm². 2. Enter the model geometry: Type the model volume (cm³), surface area (cm²) and print height (mm — the Z dimension of your model) into the geometry fields. 3. Select your material: Choose PLA, PETG, ABS, ASA, TPU, Nylon or Resin. The calculator fills in the published density and a typical retail cost per gram automatically. 4. Set slicer parameters: For FDM: enter your infill percentage, layer height, print speed, nozzle diameter and wall thickness — match these exactly to what your slicer shows. For resin: enter exposure time and lift time per layer instead. 5. Read the estimate: The calculator instantly shows estimated print time, filament mass, material volume, layer count and total material cost. The colour bar breaks the time into extrusion, travel and Z-hop (FDM) or exposure and lift (resin). FAQ: Q: How is FDM print time calculated? A: The estimator models volumetric flow rate Q = nozzle_diameter × layer_height × print_speed (mm³/s). Effective material volume is V_model × infill_fraction + surface_area × wall_thickness. Extrusion time = material_volume_mm³ / Q. A 20 % travel overhead and a 0.4 s Z-hop per layer are added. The formula matches the methodology used internally by PrusaSlicer and Cura — slicers add path-planning detail on top, so expect ±10–25 % accuracy depending on geometry complexity. Q: Why does my slicer give a different number? A: Slicers compute the exact toolpath from a mesh: they know every perimeter length, every travel move and every retraction. This estimator works from volume and surface area alone, which avoids needing the actual STL file. For complex organic geometries the difference is typically 10–25 %; for simple prismatic parts it is often under 10 %. Q: How do I find model volume in PrusaSlicer? A: Load your model, right-click it in the 3D view and choose Object > Model Info, or use the top menu Edit > Model Info. PrusaSlicer shows volume in cm³ and surface area in mm². Divide surface area by 100 to convert to cm². Q: How do I find model volume in Cura? A: In the Prepare tab, select the model and open the sidebar. Scroll to Model information — it lists the volume in cm³. Surface area is not shown directly, but you can approximate it as the mesh surface area from a tool like MeshLab (Filters > Quality Measures > Compute Geometric Measures). Q: What infill percentage should I use? A: 15–20 % gyroid or honeycomb is adequate for most decorative or non-structural parts, saving significant time and material. Functional parts that take mechanical load typically need 40–60 %. Structural or load-bearing components may need 80–100 %. Halving infill from 40 % to 20 % reduces material by roughly 25–35 % and print time proportionally. Q: Does a larger nozzle always print faster? A: Yes for the same layer height — a 0.6 mm nozzle at 0.3 mm layers moves roughly 2.25 × more material per second than a 0.4 mm nozzle at 0.2 mm layers. The trade-off is lower surface resolution on curved faces. Many users combine a 0.6 mm nozzle with 0.3 mm layers for large structural prints and switch back to 0.4 mm / 0.2 mm for detailed work. #### Knitting Gauge Calculator URL: https://geratools.com/knitting-gauge-calculator Free knitting gauge calculator. Enter your swatch measurements and target dimensions to instantly get cast-on stitches and rows needed. Supports cm and inches, positive and negative ease. Runs entirely in your browser — nothing is uploaded. How to use: 1. Knit and measure your gauge swatch: Knit a swatch of at least 15 x 15 cm (6 x 6 in) in your chosen yarn and needle size. Measure the width and height with a ruler, then count the stitches across and rows down within that measured area. 2. Enter your swatch figures: Type the swatch width, height, stitch count, and row count into the Gauge Swatch section. The calculator instantly shows you stitches and rows per 10 cm. 3. Enter your target dimensions: Type the finished width and height (or length) of the piece you want to make. Add positive ease for a relaxed fit or negative ease for a fitted one. 4. Read your cast-on and row count: The results box shows the cast-on stitch count and total rows to knit, rounded to the nearest whole stitch and row. Expand "Show calculation working" to see every step. FAQ: Q: What is a knitting gauge swatch? A: A gauge swatch is a small test square you knit before starting a project. By measuring how many stitches and rows fit into a known area (typically 10 cm x 10 cm) you establish your personal gauge for that yarn, needle size, and stitch pattern. Every knitter knits to slightly different tension, so patterns always ask you to check gauge before casting on. Q: How does the calculator work out how many stitches I need? A: It first divides your swatch stitch count by the swatch width to get stitches per centimetre (or inch). It then multiplies that rate by your target width (plus any ease). For example: 22 stitches over 10 cm = 2.2 stitches/cm. A 40 cm sweater body needs 40 × 2.2 = 88 stitches cast on. The same logic applies to rows. Q: What is ease in knitting? A: Ease is the difference between your body measurement and the finished garment measurement. Positive ease (e.g. +5 cm) makes the garment roomier. Negative ease (e.g. -3 cm) makes it stretch and hug the body. The calculator adds ease to your target width before computing the cast-on count, so you can experiment with fit without doing the maths by hand. Q: Should I use centimetres or inches? A: Use whichever your pattern specifies. The calculator accepts both — tap the cm or in button to switch. All measurements are converted internally to centimetres before the formula runs, so the results are identical regardless of which unit you choose. Q: My swatch measures something awkward like 10.3 cm — is that OK? A: Yes. Enter the actual measured value, not a rounded one. A small measurement error in the swatch gets scaled up across a full garment: 0.2 cm off over 10 cm becomes 1 cm off over 50 cm. Measuring precisely and entering the exact number gives the most accurate stitch count. Q: The calculator gives me a decimal — which way should I round? A: The calculator rounds to the nearest whole number automatically. In practice, if a stitch pattern has a repeat (e.g. a 4-stitch cable), round up or down to the nearest multiple of that repeat. The "Show calculation working" panel shows the unrounded value so you can decide how to adjust. #### Quilt Binding & Backing Calculator URL: https://geratools.com/quilt-binding-calculator Free quilt binding and backing calculator. Enter your quilt dimensions to get strip count, total binding fabric, backing panels and total yardage — rounded up to the nearest 1/8 yard. Works in inches, cm, yards or metres. How to use: 1. Enter your finished quilt dimensions: Type the width and height of your quilt top. Switch between inches and centimetres with the dropdown. 2. Set your binding strip width: Most quilters cut 2.5" strips for a standard double-fold binding. Adjust to 2.25" for a narrower finish or 3" for a wider one. 3. Set your fabric width (WOF): Most quilting cotton is 44" wide after washing. Check your bolt — some wide-backs are 108". 4. Read off the binding strips and yardage: The calculator shows how many strips to cut across the grain and the minimum yardage to purchase, already rounded up to the nearest 1/8 yard. 5. Check the backing panel count: The backing section shows how many panels you need, how they are joined (vertical or horizontal seams) and total yardage — including the standard 4-inch overhang on every side. FAQ: Q: How is the binding fabric calculated? A: The perimeter is 2 × (width + height). An extra 10 inches is added for mitered corners. That total is divided by the usable strip length (fabric width minus a 0.5" seam allowance for joins) to get the strip count. Fabric needed = strips × strip width, converted to yards and rounded up to the nearest 1/8 yard. Q: Why 2.5-inch strips? A: A 2.5" strip gives approximately 1/4" of visible binding on each side of the quilt after folding in half and wrapping to the back — the most common finished width. Narrower strips (2.25") suit delicate work; wider strips (3"+) give a chunkier look or extra wearing durability on baby quilts. Q: What is WOF and why does it matter? A: WOF stands for width of fabric — the measurement from selvage to selvage on the bolt. Most quilting cotton is 44–45" after pre-washing. Wide-back fabric can be 108". The calculator divides your required strip length by the usable WOF to count strips, so entering the correct WOF directly affects how many strips (and how much fabric) you need. Q: How is the backing yardage calculated? A: The backing must be larger than the quilt top so it extends under the quilting frame. The calculator adds 4 inches on every side (8 inches total per dimension). It then works out how many panels of your fabric width are needed to cover that backing rectangle, choosing the panel orientation (vertical or horizontal seams) that uses the least fabric. Total yardage = panels × panel length, rounded up to the nearest 1/8 yard. Q: Why does the backing sometimes use vertical versus horizontal seams? A: Rotating the panels can save significant fabric on long, narrow quilts. The calculator computes both orientations and automatically selects the more economical one. For a square quilt the saving is usually minimal; for a king-size bed quilt it can be half a yard or more. Q: Does this calculator cover wadding (batting)? A: No — wadding is typically sold pre-cut to standard sizes (cot, twin, queen, king) or by the yard off a wide roll, and its size requirement is the same as the backing: quilt dimensions plus 4 inches per side. Use the backing dimensions displayed here when buying wadding yardage from a roll. #### Yarn Yardage Calculator URL: https://geratools.com/yarn-yardage-calculator Free yarn yardage calculator for knitters and crocheters. Enter your gauge swatch, project dimensions and yarn weight to get precise yardage, metres, and skein count. Works in inches or centimetres. Runs 100% in your browser. How to use: 1. Choose your project type: Select from blanket, sweater, hat, socks, scarf, or enter custom dimensions. Preset dimensions load automatically and can be adjusted. 2. Pick your yarn weight: Choose the CYC weight class (lace through super bulky). Gauge defaults and skein size update automatically — override them with your own swatch measurements. 3. Enter your gauge: Count stitches and rows across a blocked swatch (standard is 4 in / 10 cm). Accurate gauge is the single biggest factor in getting the right yardage. 4. Read your result: The calculator shows total yards, metres, and skeins needed — plus a full line-by-line working so you can see every step. 5. Add a safety buffer: Open Advanced options and set a buffer (10% is common) to account for joins, weaving in ends, and stitch-pattern variation. FAQ: Q: How does the yarn yardage calculator work? A: It converts your gauge into stitches-per-unit-length, multiplies that across your project dimensions to get a total stitch count, then multiplies by a yarn-per-stitch constant for your chosen weight class. The formula is: total yards = (width × stitches/unit) × (height × rows/unit) × yards-per-stitch. Yarn-per-stitch averages come from Craft Yarn Council (CYC) guidelines for standard stockinette gauge. Q: What is gauge and why does it matter? A: Gauge is the number of stitches and rows in a measured swatch — typically over 4 inches (10 cm). It captures your personal combination of yarn, needle size, and tension. A difference of even one stitch per inch changes your total stitch count by 5–10% across a large project, which can mean a full extra skein. Always measure a blocked swatch rather than relying on the ball-band gauge. Q: What is yarn-per-stitch and how is it measured? A: Yarn-per-stitch (yps) is the length of yarn consumed by a single knit or purl stitch, measured in yards. It depends on yarn thickness, needle size, and stitch pattern. The calculator uses CYC weight-class averages as a default. For cables, colourwork, or textured stitches — which use more yarn — knit a sample, unravel it, measure the length, and divide by the stitch-row count. Enter that figure in the Advanced options override field. Q: Why does the calculator ask for rows as well as stitches? A: A flat rectangular project has both a stitch width and a row height. Stitches run horizontally; rows run vertically. Both dimensions contribute to the total stitch count, so both gauge figures (stitches per unit and rows per unit) are needed. For items worked in the round — like hats or socks — rows and rounds are equivalent here. Q: Should I buy extra yarn beyond the calculated amount? A: Yes, always. The 10% default buffer covers joins, weaving in ends, swatching, and minor tension variation. More importantly, buy all your yarn in one purchase from the same dye lot — even a 1–2% colour shift between lots can be visible in the finished piece. If you are doing colourwork, cables, or a stitch pattern with a high yarn-multiple, increase the buffer to 15–20%. Q: Does this work for crochet as well as knitting? A: Yes. Crochet typically uses 20–30% more yarn than knitting for the same dimensions, because hook stitches draw more loops through the fabric. Enter your actual crochet gauge swatch measurements and, if possible, measure your own yarn-per-stitch from a crocheted swatch rather than relying on the knitting defaults. The Advanced options override field is ideal for this. #### Epoxy Resin Calculator URL: https://geratools.com/epoxy-resin-calculator Free epoxy resin calculator. Enter your mould dimensions (rectangle, circle, ring) and mix ratio (1:1, 2:1, 3:1, 4:1) to get exact Part A and Part B volumes in mL, plus estimated cost and cured mass. 100% browser-based. How to use: 1. Choose your mould shape: Select rectangle, circle, ring or enter the volume directly if your mould is irregular. 2. Enter the dimensions: Type the length, width and pour depth (or diameter and depth) in centimetres or inches. 3. Set the mix ratio: Pick the ratio printed on your resin kit — most table-top epoxies are 1:1 by volume, casting systems are commonly 2:1 or 3:1. 4. Add a waste allowance: 10% is a sensible default to cover drips, cup residue and mould overfill. 5. Read Part A and Part B: The calculator shows exactly how many millilitres to measure out of each component. FAQ: Q: What does epoxy mix ratio mean? A: A mix ratio like 2:1 (resin : hardener) by volume means for every 2 mL of Part A you add 1 mL of Part B, giving 3 mL of combined mix. The ratio is set by the manufacturer to control curing chemistry — deviating from it leads to a tacky, undercured surface or a resin that never sets. Always use the ratio printed on your kit. Q: Should I mix by weight or by volume? A: Most consumer epoxy systems specify ratios by volume, which is what this calculator uses. Some professional systems — especially those used in boatbuilding or composites — specify ratios by weight. Check your product data sheet. If yours is by weight, multiply the Part A volume result by the Part A density (g/mL) and the Part B result by the Part B density to convert. Q: Why add a waste allowance? A: A small amount of mixed resin always remains in the mixing cup after pouring (typically 5–15 mL depending on cup size), and some moulds require slight overfilling to account for surface tension and any air loss. A 10% allowance is standard for small pours; use 5% for large river tables where cup waste is proportionally smaller. Q: How thick can I pour epoxy in one go? A: Standard table-top and coating epoxies generate heat as they cure (exothermic reaction). Pours deeper than roughly 6–9 mm in a single pass can overheat, yellow, crack or even smoke. Deep-pour casting resins are formulated with slower hardeners that allow single pours up to 50–75 mm. Check the maximum single-pour depth on your product data sheet before planning a river table or thick casting. Q: What is the density of cured epoxy? A: Most standard bisphenol-A epoxy systems cure to a density of approximately 1.10–1.20 g/mL (the calculator uses 1.15 g/mL as a representative average). Specialty filled systems, flexible epoxies and high-temperature resins may differ. The mass figure here is an estimate useful for shipping calculations; verify with your product spec sheet for precision work. Q: How do I measure small quantities accurately? A: For volumes under 50 mL use calibrated plastic syringes or a jewellery-grade digital scale (accuracy 0.01 g). Graduated mixing cups introduce more error than syringes for small batches. Keep Part A and Part B in separate syringes and never double-dip — cross-contamination in the bottle will cause premature gelling. #### Kerf Calculator URL: https://geratools.com/kerf-calculator Free kerf calculator for woodworkers and machinists. Enter board length, piece length and blade kerf width to see pieces per board, total kerf loss, off-cut remainder and boards needed for any quantity. Runs entirely in your browser. How to use: 1. Choose your unit of measurement: Select millimetres or inches depending on your project and the markings on your saw or measuring tape. 2. Enter the board or stock length: Type the full length of the raw material you are cutting from — for example 2400 mm for a standard metric sheet or 96 in for an 8-foot board. 3. Enter the desired piece length: Type the finished length each cut piece must be. The calculator instantly shows how many fit on one board. 4. Enter the kerf width: The kerf is the slot your blade removes. Typical values: circular saw blade 3.2 mm (1/8 in), table saw 3.2 mm, fine-tooth handsaw 1.5 mm, bandsaw 0.9 mm, track saw 2.8 mm. Check your blade spec sheet for the exact figure. 5. Set the quantity you need: Enter how many finished pieces your project requires. The calculator tells you how many boards to buy and how much material the kerfs will consume in total. 6. Read the cut-list table: Expand the cut-list table to see the exact start position, cut position and kerf-end position for every piece on a single board — useful for marking up your stock before cutting. FAQ: Q: What is a kerf in woodworking? A: A kerf is the narrow slot a saw blade cuts through material as it passes. The blade removes a thin sliver of wood (or metal, plastic, etc.) equal to the blade's tooth-set width. Because that material is turned to dust and shavings, it is lost forever — which is why you must account for it when planning how many pieces fit on a board. Q: How wide is a typical saw kerf? A: Common kerf widths: standard circular saw blade 3.0–3.5 mm (about 1/8 in); table saw 3.2 mm; thin-kerf table saw blade 2.4 mm; fine handsaw 1.2–1.8 mm; bandsaw 0.9–1.2 mm; track saw 2.6–3.0 mm; laser cutter 0.1–0.3 mm. The exact value is printed on the blade packaging or in the manufacturer spec sheet. Q: Why does kerf loss matter for a cut list? A: On a short project the loss is trivial, but it compounds quickly. Cutting twenty 400 mm pieces with a 3.2 mm kerf removes 60.8 mm from a single 2400 mm board — that is more than 2.5 % of the board gone before a single piece is measured. If you ignore kerf when ordering timber, you frequently run short on the last board. Q: What is the formula for pieces per board? A: The standard formula is: n = floor((L + k) / (p + k)), where L is the board length, p is the piece length and k is the kerf width. The (L + k) trick works because the last piece does not need a trailing kerf, so you can add one virtual kerf to the board length to make the arithmetic symmetric. Q: What is an off-cut or remainder? A: After all full pieces have been cut from a board, whatever material is left is the off-cut. The calculator shows this remainder in your chosen unit. A large off-cut can often be used for smaller pieces in the same project or saved for future work. Q: How do I reduce kerf waste? A: Use the thinnest blade that suits the material and cut quality you need (bandsaw or thin-kerf blade instead of a standard circular saw). Nest identical pieces back-to-back so one board yields more pieces. Optimise piece length so the off-cut from one board is long enough to yield pieces for a different part of the project. #### Soap Lye Calculator URL: https://geratools.com/soap-lye-calculator Free soap lye calculator: enter your oils, choose NaOH (bar soap) or KOH (liquid soap), set superfat and lye concentration, and get precise lye and water amounts instantly. Runs entirely in your browser — no data uploaded. How to use: 1. Choose your lye type: Select NaOH for hard bar soap or KOH for liquid or paste soap. If using KOH, enter the purity percentage shown on your supplier's label (typically 90%). 2. Set superfat and lye concentration: Superfat (3–8% is typical) is the percentage of oils left unsaponified for extra skin conditioning. Lye concentration (28–33% is standard) controls how much water you use relative to lye. 3. Enter your oils: Pick each oil or fat from the dropdown and enter its weight in grams or ounces. Add more oils with the + Add oil button. You can combine up to 16 different fats. 4. Read the results: The calculator shows the exact NaOH or KOH amount, distilled water amount, and total batch weight. Expand 'Show formula working' to verify every step. FAQ: Q: What is saponification and why does the SAP value matter? A: Saponification is the chemical reaction between a fat (triglyceride) and a strong alkali (lye) that produces soap (salt of a fatty acid) and glycerol. Each oil has a unique fatty acid profile, so a fixed gram of lye saponifies a different quantity of each fat. The SAP (saponification) value is the number of grams of lye required to fully saponify exactly one gram of a given oil. The calculator multiplies each oil weight by its SAP value, sums the results, then applies your superfat discount. Q: What is superfat and what percentage should I use? A: Superfat is a deliberate lye discount — you use less lye than would be needed to saponify every gram of oil, leaving a small fraction of free unsaponified fat in the finished bar. This softens the lather and leaves the skin feeling conditioned. A superfat of 5% is the most common starting point for bar soap. Go lower (2–3%) for shampoo bars or laundry soap where full cleansing is the goal, or slightly higher (6–8%) for a more luxurious feel. Above 8% the soap may feel greasy and will have a shorter shelf life. Q: What is the difference between NaOH and KOH? A: NaOH (sodium hydroxide, caustic soda) is used for hard bar soap because sodium soaps are solid at room temperature. KOH (potassium hydroxide, caustic potash) is used for liquid or paste soap because potassium soaps remain fluid. KOH has a higher molecular weight than NaOH, so its SAP values are roughly 40% higher. Commercial KOH is often only 90% pure; the calculator divides the theoretical KOH SAP value by the purity fraction to give you the correct real-world amount to weigh. Q: How is the water amount calculated? A: The calculator uses lye concentration to determine water. Lye concentration is defined as: lye_conc (%) = lye_weight / (lye_weight + water_weight) × 100. Rearranging gives: water = lye × (100 / lye_conc − 1). At 30% lye concentration, for every 100 g of lye you add 233 g of water. A lower concentration (more water) gives a slower trace and longer curing window; a higher concentration (less water) speeds trace and unmoulding but increases the risk of soda ash on bar soap. Q: Why must I add lye to water and not water to lye? A: When lye dissolves in water it releases a large amount of heat and can briefly reach 80 °C. Adding water to a concentrated lye pile risks a violent steam explosion and violent spattering of caustic liquid. Adding lye granules slowly to a larger volume of cold water disperses the heat safely and gives you control. Always wear heat-resistant gloves and safety glasses, work near an open window or outdoors, and never use aluminium vessels (lye reacts with aluminium releasing hydrogen gas). Q: Can I use tap water instead of distilled water? A: Distilled or deionised water is strongly recommended. Tap water contains minerals, chlorine, and other dissolved solids that can interfere with saponification, cause rancidity, or leave white spots on finished soap. Rainwater, filtered water, or cooled herbal infusions are used by experienced soapers, but start with distilled water until you are confident in the process. #### Wood Shrinkage Calculator URL: https://geratools.com/wood-shrinkage-calculator Free wood shrinkage calculator covering 32 hardwood and softwood species. Enter your board dimensions, starting and target moisture content, and saw orientation to see precise width, thickness and volume loss. Uses USDA Wood Handbook shrinkage coefficients. Runs entirely in your browser. How to use: 1. Choose your wood species: Select from 32 species covering common hardwoods and softwoods. The calculator loads USDA-verified radial and tangential shrinkage coefficients automatically. 2. Set saw orientation: Pick flatsawn, quartersawn, or riftsawn. This determines which shrinkage coefficient applies to the width versus the thickness of your board. 3. Enter moisture content range: Set starting MC (fresh-sawn lumber is typically 28-100%) and target MC. Use the quick-pick buttons for kiln-dry (8%), air-dry (12%), or outdoor (15%). 4. Enter green board dimensions: Type the width, thickness and length of your board as it comes off the saw. Switch between inches and millimetres with the unit toggle. FAQ: Q: What is the Fibre Saturation Point and why does it matter? A: The Fibre Saturation Point (FSP) is the moisture content at which cell walls are fully saturated but no free water remains in the cell cavities — roughly 28% for most temperate species. Wood only shrinks or swells when moisture changes below the FSP. Above 28% MC, the cell walls are already fully swollen, so drying a green board from 80% down to 28% causes no dimensional change. All shrinkage happens in the 28-to-0% range. Q: What is the difference between tangential and radial shrinkage? A: Radial shrinkage occurs across the growth rings (toward and away from the centre of the tree), while tangential shrinkage occurs along the growth rings (around the circumference). Tangential shrinkage is almost always larger than radial — typically 1.5 to 2.5 times larger — which is why flatsawn boards cup and check more than quartersawn boards of the same species. Q: Why does flatsawn lumber move more than quartersawn lumber? A: In a flatsawn board the growth rings run roughly parallel to the face, so the face width shrinks at the higher tangential rate. In a quartersawn board the rings run perpendicular to the face, so the width shrinks at the lower radial rate. The difference can be dramatic with high T/R ratio species like beech (11.9% T vs 5.5% R) and is the main reason quartersawn flooring and furniture panels are more dimensionally stable. Q: What is the T/R ratio and what does it tell me? A: The tangential-to-radial (T/R) ratio compares a species' two shrinkage directions. A ratio below 1.4 is excellent stability, 1.4-1.7 is good, 1.7-2.0 is moderate, and above 2.0 is poor. Low-ratio species like yellow birch (1.30) and paper birch (1.37) are prized for joinery because they move proportionally in both directions, reducing the tendency to cup or warp. Note that teak (2.32) and western red cedar (2.08) both have high T/R ratios — their outdoor reputation comes from very low absolute shrinkage values (teak: R 2.5%, T 5.8%), not from a balanced T/R ratio. Q: How do I read the formula this calculator uses? A: The USDA standard shrinkage formula is: shrinkage% = S × (MC_start - MC_final) / FSP, where S is the total green-to-oven-dry shrinkage coefficient for that species and direction, MC values are in percent, and FSP is 28. This is a linear interpolation — the assumption is that wood shrinks uniformly between FSP and oven-dry. Real-world shrinkage is slightly non-linear at very low MC, but the linear model is accurate enough for all practical workshop calculations. Q: Does wood shrink along its length? A: Very little. Longitudinal (along-the-grain) shrinkage is typically just 0.1-0.3% for straight-grained wood, roughly 30-50 times less than tangential shrinkage. The calculator uses 0.2% as the standard longitudinal coefficient. Spiral grain, reaction wood, and juvenile wood can push longitudinal shrinkage higher, but for normal sawn timber it is effectively negligible compared to width and thickness changes. Q: What moisture content should I target for indoor furniture? A: Interior furniture in a heated home typically equilibrates to 6-8% MC in dry climates and 8-11% in humid ones. Kiln-dried lumber at 8% is therefore a good starting point for most indoor work. For outdoor furniture or decking, target 12-15% to match average ambient conditions. Always allow freshly kiln-dried stock to acclimatise to the shop for at least a week before cutting joints. ### Finance & Money #### Compound Interest & Savings Calculator URL: https://geratools.com/compound-interest-calculator Free compound interest and savings-goal calculator. See the future value of your savings, total interest earned and an inflation-adjusted "today's money" figure. Runs entirely in your browser. How to use: 1. Enter your starting amount and contribution: Add your initial savings and how much you'll add each month. 2. Set the rate and term: Enter the annual interest rate, the number of years and how often interest compounds. 3. Toggle inflation: Turn on inflation adjustment to see the future value in today's money. FAQ: Q: What is compound interest? A: Interest earned on both your original savings and the interest already added. Over time this compounding effect accelerates growth, so money left to compound for longer grows disproportionately. Q: How does the inflation toggle work? A: It discounts the future value by your chosen inflation rate so you can see roughly what the balance would be worth in today's purchasing power, dividing by (1 + inflation)^years. Q: Does compounding frequency really matter? A: A little. At the same annual rate, daily compounding produces slightly more than monthly, which beats yearly — but the gap is small. Your contribution amount and time horizon matter far more than the compounding interval. Q: How does the calculator handle my monthly deposits? A: It treats contributions as added during each compounding period. Annual contributions (your monthly amount × 12) are split across the periods per year, then interest is applied period by period. Q: What is the rule of 72? A: A quick mental shortcut — divide 72 by your annual interest rate to estimate the years it takes money to double. At 6% that's about 12 years. This calculator gives the exact figure including your ongoing deposits. Q: Why does the interest earned grow faster in later years? A: Because each year's interest is calculated on a larger balance that already includes prior interest. The same rate applied to a bigger pot produces a bigger gain, which is why most growth happens near the end of a long term. Q: Are my figures stored anywhere? A: No. The projection is calculated entirely in your browser. #### Free Invoice Generator URL: https://geratools.com/invoice-generator Free online invoice generator. Add line items, tax, discounts and your logo, then download a professional PDF — all in your browser. Saved clients and reusable items persist locally; nothing is uploaded. How to use: 1. Enter your business and client details: Fill in your name, address and email under From, then the client under Bill to. Save the client to reuse them next time. 2. Add line items: Type a description, quantity and unit price for each line. The amount and running totals update instantly. Star an item to keep it in your reusable catalogue. 3. Set tax, discount and your logo: Choose a currency, set the tax rate and label (VAT, GST, Sales Tax), add an optional percentage discount, and upload your logo. 4. Download the PDF: Click Download PDF to export a print-ready, branded invoice. Everything stays on your device. FAQ: Q: Is this invoice generator really free? A: Yes — completely free with no sign-up, no watermark and no limit on how many invoices you create. It runs entirely in your browser, so there is no account to manage and no subscription. Q: Where are my invoices and client details stored? A: Only in your own browser, using localStorage. Your business details, saved clients and reusable catalogue items stay on this device and are never uploaded to any server. Clearing your browser data will remove them. Q: How do I add my company logo to the invoice? A: Upload a PNG or JPG under "Your logo". It appears in the top-left of the exported PDF and is remembered for your next invoice, so you only set it once. Q: Can I charge VAT, GST or sales tax? A: Yes. Set the tax rate as a percentage and rename the tax label to VAT, GST, Sales Tax or anything else. Tax is applied to the subtotal after any discount, and the breakdown is itemised on the PDF. Q: Does it support different currencies? A: It supports GBP, USD, EUR, AUD, CAD, INR and AED. Pick a currency and every amount — line items, subtotal, tax and total — is formatted with the correct symbol and locale, both on screen and in the PDF. Q: Can I reuse clients and line items? A: Yes. Save a client once and load them from a dropdown on future invoices. Star any line item to add it to your catalogue, then add it back to any invoice in one click — ideal for recurring services or products. #### Loan & Personal Credit Calculator URL: https://geratools.com/loan-calculator Free loan and personal-credit calculator. Work out your monthly payment, total interest, total cost of credit and representative APR including arrangement fees. Runs entirely in your browser. How to use: 1. Enter the loan amount and rate: Type how much you want to borrow and the annual interest rate. 2. Set the term and any fees: Add the term in years and any arrangement fees that are financed into the loan. 3. Read the results: See the monthly payment, total interest, total cost of credit and the representative APR. FAQ: Q: What is the difference between interest rate and APR? A: The interest rate is the cost of borrowing the money; the representative APR also folds in fees, so it reflects the true annual cost of the credit on the cash you actually receive. Q: How is total cost of credit calculated? A: It's everything you repay (all monthly payments) minus the original amount you borrowed — that is, the interest plus any fees. Q: How is the monthly loan payment worked out? A: It uses the amortising-loan formula M = P·r(1+r)ⁿ / ((1+r)ⁿ−1), where P is the amount borrowed plus any financed fees, r is the monthly rate (annual rate ÷ 12) and n is the term in months. Q: Does a longer loan term reduce the cost? A: No. A longer term lowers the monthly payment but increases total interest, because you owe the balance for longer. Shorten the term here to see how much interest you save against a higher monthly cost. Q: Why is the representative APR higher than my interest rate? A: When fees are financed into the loan you repay the full amount but receive less cash, so the effective annual cost rises. With no fees the representative APR equals the entered interest rate. Q: Can I use this for a car loan or HP agreement? A: Yes, for any fixed-rate, fixed-term amortising loan with equal monthly payments. It does not model balloon payments, deferred final payments or 0% promotional periods. Q: Is this a credit offer? A: No. It's a guidance calculator only and runs entirely in your browser. #### Tip Calculator & Bill Splitter URL: https://geratools.com/tip-calculator Free tip calculator and bill splitter. Add a tip, split between any number of people, round up the total and share the result via link. Runs entirely in your browser. How to use: 1. Enter the bill and tip: Type the bill amount and choose a tip percentage, or tap a preset. 2. Split between people: Set the number of people to see the amount each person owes. 3. Share the result: Optionally round the total up, then copy the shareable link to send to the table. FAQ: Q: Can I split the bill unevenly? A: This version splits evenly between the chosen number of people. Use the round-up option and per-person figure to settle uneven shares manually. Q: How does the shareable link work? A: Your inputs are stored in the URL after the Q: How much should I tip? A: It varies by country. In the US 15–20% is standard for table service (the calculator offers 18% and 20% presets); in the UK 10–12.5% is common and often already added as a service charge; much of Europe and Asia rounds up or tips little. Tap a preset or type any percentage. Q: Is the tip calculated before or after tax? A: This tool applies the tip percentage to the bill amount you enter. If you want to tip on the pre-tax subtotal, enter that figure as the bill; if you want to tip on the full taxed total, enter the total instead. Q: How does the round-up option affect the tip? A: Ticking "round up" rounds the grand total to the next whole currency unit, and the extra goes into the tip. The "Tip" figure shown is the adjusted tip after rounding, so the numbers always add up to the displayed total. Q: How is each person's share worked out? A: The total (bill + tip, after any round-up) is divided by the number of people. Five people on a £63 total each pay £12.60. Change the number of people and the per-person figure updates live. Q: Is my bill data private? A: Yes — everything is calculated in your browser and only ever stored in the page URL if you choose to share it. #### Monthly Budget Planner URL: https://geratools.com/budget-planner A free monthly budget planner that runs entirely in your browser. Add income and expense categories, see your savings rate and money left over, and watch a live spending breakdown chart. Everything is saved locally — nothing is uploaded. How to use: 1. Set your currency: Pick your currency at the top so every figure and the export use the right symbol. 2. Add your income: Add each source of monthly income — salary, freelance work, benefits — using the Add row with the type set to Income. 3. List your expenses: Add every recurring monthly cost as an expense category, from rent and groceries to subscriptions and savings transfers. 4. Read your summary: The summary band shows total income, total expenses, money left over (or shortfall) and your savings rate, all updating instantly. 5. Export or come back later: Export the whole budget to CSV for your records, or just close the tab — it is saved in your browser and reloads exactly as you left it. FAQ: Q: How does this budget planner calculate my savings rate? A: Savings rate is the money left over after expenses divided by total income, expressed as a percentage: (income − expenses) ÷ income × 100. A rate of 20% or higher is widely considered healthy, so the figure turns amber below that threshold. Q: Is my financial data private? A: Completely. The planner runs 100% in your browser and saves your figures in local storage on this device only. Nothing is ever sent to a server, so no one — including us — can see your numbers. Q: Will my budget still be here when I come back? A: Yes. Every change is saved to your browser automatically, so when you reopen the page on the same device and browser your categories and amounts are restored exactly as you left them. Q: Can I use this for a weekly or annual budget instead of monthly? A: Yes. The maths is the same for any period — just treat every amount as your weekly or annual figure and read the totals the same way. For consistency, keep all amounts on the same time basis (don't mix weekly rent with annual insurance). Q: How do I clear the sample data and start fresh? A: Click Clear to remove every category, or Sample data to reload the example budget. From an empty list, add your own income and expense categories one by one. Q: What is the 50/30/20 rule and does this tool follow it? A: The 50/30/20 rule splits take-home pay into 50% needs, 30% wants and 20% savings. This planner lets you build any categories you like rather than forcing that split, but you can model it by grouping your expenses accordingly and watching the savings rate hit 20%. #### Currency Conversion Margin Calculator URL: https://geratools.com/currency-conversion-margin Free currency conversion margin calculator. Compare the real mid-market (interbank) rate with the rate your bank or app actually offered to reveal the hidden markup, plus any fixed fee, and the total cost of a transfer. Runs entirely in your browser — nothing is uploaded. How to use: 1. Look up the mid-market rate: Find the real interbank rate for your currency pair from a rate-comparison source and enter it as the mid-market rate. 2. Enter the rate you were quoted: Type the exchange rate your bank, card or transfer app actually offered, plus any fixed fee they charge. 3. Read the margin and total cost: The calculator shows the percentage markup baked into the rate and the total cost of the transfer versus converting at the mid-market rate. FAQ: Q: What is the mid-market rate? A: The mid-market (or interbank) rate is the midpoint between the buy and sell prices that banks use to trade with each other. It is the fairest reference rate and the one most rate-lookup tools show. Providers add a margin to it, which is where much of their profit comes from. Q: How is the exchange-rate margin calculated? A: Margin % = (mid-market rate − quoted rate) ÷ mid-market rate × 100. A mid-market rate of 1.1700 versus a quoted 1.1350 is a margin of (1.1700 − 1.1350) ÷ 1.1700 = 2.99%. Q: Why does a "no fee" transfer still cost money? A: A zero-fee transfer can still carry a wide exchange-rate margin, which is a fee by another name. This tool converts that hidden margin into a cash figure so you can compare a low-fee-wide-margin provider against a fee-charging one on total cost. Q: Is my transfer data private? A: Completely. All figures are calculated inside your browser and nothing you enter is sent to a server or stored. #### Remortgage Savings Calculator URL: https://geratools.com/remortgage-savings-calculator Free remortgage savings calculator. Enter your outstanding balance, remaining term and both interest rates to see how much switching to a new mortgage deal saves each month and over the term, after fees, plus the fee break-even point. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your current mortgage: Type the outstanding balance, the number of years left on the term and your current interest rate. 2. Enter the new deal: Add the interest rate of the deal you are considering and any switching or product fees it carries. 3. Read the saving and break-even: The calculator shows the monthly saving, the lifetime saving after fees, and how many months it takes for the saving to recover the switching fees. FAQ: Q: How is the remortgage saving calculated? A: Both the current and new monthly payments use the standard amortising formula P × r ÷ (1 − (1 + r)^−n), where r is the monthly rate and n the number of months. The monthly saving is the difference; the lifetime saving is that difference across the term, minus any switching fees. Q: What is the fee break-even point? A: It is the number of months of savings needed to recover the switching fees — calculated as fees ÷ monthly saving. If you plan to stay on the new deal longer than the break-even period, switching is worthwhile on cost alone. Q: Should I include product and legal fees? A: Yes — enter all one-off costs of switching (arrangement, product, valuation and legal fees, net of any cashback) in the fees box so the lifetime saving and break-even reflect the true cost of moving. Q: Does this assume the rate lasts the whole term? A: For simplicity the calculation applies each rate across the full remaining term. Most deals are fixed for an initial period, so treat the lifetime figure as an illustration and re-run it when your fixed period ends. Q: Is my mortgage data private? A: Completely. Every figure is calculated inside your browser and nothing you enter is sent to a server or stored. #### Margin Calculator URL: https://geratools.com/margin-calculator Free profit margin calculator. Enter cost and price, or cost and a target margin or markup, to get the gross margin percentage, markup percentage, profit and selling price. Clears up the margin-vs-markup confusion. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose what you know: Pick whether you are solving from cost and price, cost and a target margin, or cost and a target markup. 2. Enter the figures: Type the item cost and the second value for the mode you chose. 3. Read margin, markup, profit and price: The calculator returns the selling price, profit, gross margin percentage and markup percentage together so you can see how they relate. FAQ: Q: What is the difference between margin and markup? A: Margin is profit as a percentage of the selling price (profit ÷ price), while markup is profit as a percentage of the cost (profit ÷ cost). Because the selling price is larger than the cost, the margin percentage is always smaller than the markup percentage for the same item. Q: How do I calculate gross margin? A: Gross margin % = (selling price − cost) ÷ selling price × 100. An item costing 60 sold for 100 has a margin of (100 − 60) ÷ 100 = 40%. Q: How do I set a price for a target margin? A: To hit a target margin, price = cost ÷ (1 − margin). For a 40% margin on a 60 cost, price = 60 ÷ (1 − 0.40) = 100. The calculator does this automatically in the "Cost + Margin %" mode. Q: Can margin be 100% or more? A: No. Margin is capped below 100% because profit can never exceed the selling price. Markup, however, has no upper limit — a 66.7% markup equals a 40% margin, and markups above 100% are common. Q: Is my pricing data private? A: Completely. Every figure is calculated inside your browser and nothing you enter is sent to a server or stored. #### Alabama Auto Loan Calculator URL: https://geratools.com/alabama-auto-loan-calculator Estimate your Alabama car loan monthly payment with the state's 4.00% sales tax rolled into the financed amount. Accounts for down payment, trade-in, term, and APR to show the true monthly cost and total interest in Alabama. How to use: 1. Enter the vehicle price and trade-in: Type the negotiated car price and any trade-in value. The trade-in is subtracted before sales tax is applied. 2. Add Alabama sales tax automatically: The tool rolls Alabama's 4.00% sales tax into the taxable amount, then subtracts your down payment to get the financed total. 3. Set the APR and term: Enter your interest rate and loan length in years to see the monthly payment and total interest. FAQ: Q: What sales tax rate does this Alabama auto loan calculator use? A: Alabama applies a 4.00% sales tax. The calculator taxes the price after your trade-in credit, so on a $30,000 car with a $5,000 trade-in the tax is charged on $25,000, adding about $1,000. Q: Is Alabama sales tax charged before or after the trade-in? A: This calculator applies tax after the trade-in credit, which is how most states assess vehicle sales tax. Trading in a car lowers the taxable amount and therefore the tax you pay. Q: How is the monthly payment calculated? A: It uses the standard amortization formula on the financed amount (taxed price minus down payment), with the monthly rate equal to your APR divided by 12 over the number of months in the term. Q: Does this include title, registration, or dealer fees? A: No. The estimate covers price, sales tax, trade-in, down payment, APR and term. Title, registration, documentation and any local fees in Alabama are separate and vary by county and dealer. Q: Is this Alabama estimate financial advice? A: No. It is a planning estimate only. Confirm the exact tax, fees and APR with your Alabama dealer, lender and the state revenue or motor-vehicle department before signing. Q: Why might my real Alabama tax rate differ from 4.00%? A: Alabama's state automotive sales-tax rate is a reduced 2%, but counties and cities add their own automotive rates on top, so the combined rate varies by where you register the vehicle. The 4.00% default is a combined-rate approximation — check your local automotive rates with the Alabama Department of Revenue and adjust. Q: Do I pay Alabama sales tax when buying from a private seller? A: Yes. Alabama levies casual sales tax on private-party vehicle purchases, collected at the county licensing office when you title and register the car, rather than by the seller. The state automotive rate plus your local automotive rates apply. #### Arkansas Workers' Compensation Premium Calculator URL: https://geratools.com/arkansas-workers-comp-calculator Estimate an Arkansas workers' compensation premium using the class-code base rate per $100 of payroll, annual payroll, and your experience modifier. Shows manual premium and modified premium so you can budget the insurance cost. Runs entirely in your browser. How to use: 1. Enter your class-code rate: Type the base rate per $100 of payroll for your job classification code, found on your policy or quote. 2. Enter annual payroll and modifier: Add your total annual payroll for that class and your experience modification factor (1.00 is average; below 1.00 is a discount). 3. Read the premium: The tool computes the manual premium and then applies your experience modifier to show the estimated annual premium. FAQ: Q: How is a workers' comp premium calculated in Arkansas? A: The core formula is payroll divided by 100, multiplied by the class-code rate, multiplied by your experience modifier. The class rate is expressed per $100 of payroll, so a $0.75 rate on $500,000 of payroll is a $3,750 manual premium before the modifier. Q: What is an experience modifier? A: The experience modification factor (mod) adjusts your premium based on your claims history versus similar employers. A mod of 1.00 is average, below 1.00 earns a credit (lower premium), and above 1.00 is a surcharge. New employers usually start at 1.00. Q: Where do I find my class-code rate? A: Your insurance carrier or agent assigns classification codes (NCCI codes) to your work and lists the rate per $100 of payroll on your quote or policy. Riskier work like roofing carries a much higher rate than clerical office work. Q: Does Arkansas use a state fund or private carriers? A: Arkansas workers' compensation is provided through private insurance carriers and self-insurance, regulated by the Arkansas Workers' Compensation Commission; there is no exclusive monopolistic state fund. Rates are filed by carriers based on NCCI loss costs. Q: Is this an exact premium? A: No, it is an estimate of the basic premium. Final cost also reflects carrier expense loadings, schedule credits/debits, minimum premiums, assessments, and payroll audits. Get a formal quote from a licensed Arkansas carrier or agent. Q: Does overtime pay increase my workers' comp premium? A: Only partially. Under standard NCCI payroll rules the overtime excess — the extra half in time-and-a-half — is generally excluded from the premium basis, so only the straight-time portion counts. Your payroll records must separately track overtime for the exclusion to be applied at audit. Q: Do payments to subcontractors affect my premium? A: They can. If a subcontractor cannot produce a certificate showing their own workers' compensation coverage, auditors commonly charge those payments to your policy as payroll. Collecting certificates of insurance from every subcontractor before work begins protects you from surprise audit bills. #### Baseball Stolen Base Break-Even Calculator URL: https://geratools.com/baseball-stolen-base-break-even-calculator Enter run-expectancy values for the current, success, and caught-stealing base-out states to compute the break-even stolen-base success rate, typically around 70 to 75 percent, below which attempting the steal costs the team expected runs. Runs in your browser. How to use: 1. Enter the current run expectancy: Type the run expectancy for the present base-out state, such as a runner on first with zero outs. 2. Enter success and caught states: Add the run expectancy if the steal succeeds and the lower value if the runner is caught, with one more out. 3. Read the break-even rate: The tool returns the success rate at which attempting the steal is exactly neutral, plus a verdict for your actual rate. FAQ: Q: What is the break-even stolen base success rate? A: It is the success probability at which a steal attempt neither adds nor subtracts expected runs. Using standard run-expectancy tables, stealing second with no outs sits near 70 to 75 percent, meaning you must succeed that often just to break even. Q: Why is being caught more costly than the advance is valuable? A: A caught stealing removes the runner and adds an out, wiping out a chunk of run expectancy. The advance only nudges expectancy up by one base. Because the downside outweighs the upside, the break-even success rate is well above 50 percent. Q: Where do the run-expectancy numbers come from? A: Run expectancy comes from league-wide play-by-play data that averages how many runs score from each of the 24 base-out states. The defaults here reflect a typical modern MLB table; you can substitute your league's own values. Q: How is the break-even formula derived? A: Let gain be the run-expectancy rise on success and loss be the drop if caught. Setting expected change to zero gives break-even equals loss divided by gain plus loss. That single ratio captures the whole risk-reward trade-off. Q: Does this account for game situation? A: It is built on average run expectancy, not win probability. In late, close games the win-probability break-even can be higher or lower. Use this for general strategy and adjust for score, inning, and the batter at the plate. #### Cargo Stowage Factor Calculator URL: https://geratools.com/cargo-stowage-factor-calculator Search a built-in table of stowage factors for bulk, break-bulk, and bagged commodities, convert between m3/MT and ft3/LT, and compute how much cargo a hold carries given its volume and deadweight. Built for cargo officers and chartering managers. How to use: 1. Find the commodity: Type a cargo name or group into the search box to filter the embedded stowage factor table, then press "use" to load its factor. 2. Enter the hold figures: Set the hold or hatch grain volume in cubic metres and the deadweight available for this parcel in metric tonnes. 3. Read the loadable cargo: The tool reports the mass that fills the hold by volume, the actual loadable tonnage, the limiting factor, and volume utilisation. FAQ: Q: What is a stowage factor? A: A stowage factor is the volume that one unit of mass of a cargo occupies once stowed, including the void space between and within packages (broken stowage). It is quoted as m3/MT in metric or ft3/LT in imperial. Q: How do you convert m3/MT to ft3/LT? A: Multiply m3/MT by 35.8814. That factor combines 35.3147 cubic feet per cubic metre with the 1.01605 metric tonnes per long ton. So 1.30 m3/MT is about 46.6 ft3/LT. Q: What does full and down mean? A: A hold is full and down when it reaches both its volume capacity and its deadweight limit at the same time. If the cargo runs out of space first it is space-limited, and if it runs out of weight allowance first it is weight-limited. Q: Why are table values approximate? A: Stowage factor varies with moisture, packing, compaction, and trimming. The table gives typical mid-range values for planning. For a fixture or load plan always use the figure from the cargo declaration or a recent draught survey. Q: Does a lower stowage factor mean more cargo? A: A lower stowage factor means denser cargo, so more tonnes fit in the same volume. Iron ore at about 0.34 m3/MT is far denser than baled cotton at about 2.6 m3/MT, which means an ore parcel hits the deadweight limit long before it fills the space. #### Currency Minor Unit Converter URL: https://geratools.com/currency-minor-unit Free currency minor unit converter. Turn dollars into cents and back using the correct ISO 4217 exponent for each currency — 2 for USD, 0 for JPY, 3 for BHD. Get the exact integer amount that payment APIs like Stripe expect. Runs entirely in your browser. How to use: 1. Pick the currency: Select your ISO 4217 currency from the list; its minor-unit exponent (0, 2, or 3) is shown next to the code. 2. Choose the direction: Convert major units to minor units (dollars to cents) or minor units back to major units (cents to dollars). 3. Read the integer result: Enter the amount and read the converted value, with the exact formula shown so you can verify what your payment API should receive. FAQ: Q: What is a currency minor unit? A: A minor unit is the smallest denomination of a currency — cents for the US dollar, pence for the pound, fils for the dinar. ISO 4217 defines an exponent for each currency that says how many decimal digits the minor unit has, which is how you convert between the two. Q: Why do payment APIs want amounts in cents? A: APIs such as Stripe, PayPal, and Adyen represent money as integers in the smallest unit to avoid floating-point rounding errors. So $19.99 is sent as 1999. Using integers means a payment of $0.10 is always exactly 10, never 9.9999999. Q: Why is the multiplier not always 100? A: Most currencies have an exponent of 2, so you multiply by 100. But the Japanese yen has exponent 0 (no subunit, so the multiplier is 1) and Gulf dinars like BHD and KWD have exponent 3, so you multiply by 1000. Hard-coding ×100 silently overcharges or undercharges those currencies. Q: How does the tool avoid floating-point errors? A: When converting major to minor it multiplies by ten to the exponent and rounds to the nearest integer. This corrects artifacts such as 19.99 × 100 evaluating to 1998.9999999, which would otherwise truncate to 1998 instead of the correct 1999. Q: What happens with zero-decimal currencies like JPY? A: Zero-decimal currencies have exponent 0, meaning the major and minor amounts are identical — ¥2000 is sent as 2000, not 200000. The converter detects this and tells you the units are the same, which is a common source of 100x overcharge bugs. #### Currency Banknote Grade Reference Tool URL: https://geratools.com/currency-note-grade-reference Select a numeric paper-money grade from 1 to 70 to display the standard criteria — folds, crispness, soiling, margins, and centering — per PMG and PCGS Banknote grading. For paper money collectors and currency enthusiasts. How to use: 1. Pick a numeric grade: Choose a grade from 1 (Poor) up to 70 (Gem Uncirculated) on the 70-point paper-money scale used by PMG. 2. Read the criteria: The tool shows the grade adjective, the broad tier, and the standard description covering folds, body, soiling, and centering. 3. Compare with adjacent grades: Step through nearby grades to see how the number of folds and the loss of crispness move a note from one grade to the next. FAQ: Q: What scale do PMG and PCGS use for paper money? A: Both use a 70-point numeric scale adapted from the Sheldon coin scale. It runs from 1 (Poor) through circulated grades to 70 (Gem Uncirculated). Grades of 60 and above are Uncirculated, meaning no folds or circulation wear. Q: What separates Uncirculated from About Uncirculated? A: An Uncirculated note (60-70) has never been folded or handled in circulation and retains full crispness and original embossing. An About Uncirculated note (50-58) is nearly perfect but shows a light fold, corner bend, or minor handling. Q: What does EPQ or PPQ mean on a slab? A: EPQ (Exceptional Paper Quality, PMG) and PPQ (Premium Paper Quality, PCGS) certify that the note has original, unprocessed paper with full embossing and no restoration. It is a separate qualifier that adds value on top of the numeric grade. Q: How do folds affect the grade? A: Folds are the main driver of circulated grades. A single light fold may still be Extremely Fine, several folds push a note to Very Fine or Fine, and heavy multiple folds with limpness drop it to Good or below. Q: Does centering matter for banknotes? A: Yes. Even an Uncirculated note grades higher with even, balanced margins. Poor centering where the design runs close to or off one edge can cap the grade below Gem, just as it does with stamps and coins. #### FPV Drone Link Budget Calculator URL: https://geratools.com/fpv-link-budget-calculator Enter transmitter power in mW, transmit and receive antenna gain in dBi, frequency, and receiver sensitivity to compute the free-space link budget and theoretical maximum range for an FPV video link. Built for FPV pilots. How to use: 1. Enter transmitter power and gains: Type the VTX output power in milliwatts, then the transmit and receive antenna gains in dBi. The tool converts power to dBm automatically. 2. Set frequency and sensitivity: Choose your video band frequency in MHz and enter the receiver sensitivity in dBm (a negative number, often around -90 dBm). 3. Read the link margin and range: The calculator shows the free-space path loss, received signal level, link margin, and the theoretical maximum range where the margin reaches zero. FAQ: Q: What is a link budget? A: A link budget is the sum of all gains and losses between a transmitter and receiver. It starts with transmit power, adds antenna gains, subtracts path loss, and compares the result against receiver sensitivity. A positive link margin means the signal is strong enough to be decoded; a negative margin means the link drops out. Q: What is the free-space path loss formula? A: FSPL in dB equals 20·log10(d) + 20·log10(f) + 32.45, where d is distance in kilometres and f is frequency in MHz. It models signal weakening in open air with line of sight. Real FPV flights have extra losses from obstacles, the ground, and antenna polarisation mismatch, so achievable range is always less than the free-space figure. Q: Why does higher frequency reduce range? A: Free-space path loss rises with frequency, so a 5800 MHz (5.8 GHz) link loses more signal over the same distance than a 1300 MHz link. That is why long-range FPV often uses lower bands. Higher frequencies allow smaller antennas and more channels, which is why 5.8 GHz dominates racing despite the shorter range. Q: What receiver sensitivity should I use? A: Analog FPV receivers are typically around -85 to -90 dBm for a usable picture. Digital systems vary; check your goggle or VRX datasheet. A more negative number means a more sensitive receiver and longer range. The tool uses sensitivity as the threshold at which the link margin hits zero. Q: Does this account for obstacles and interference? A: No. This is a free-space, line-of-sight estimate that assumes a clear path and perfectly matched antennas. Trees, buildings, ground reflection, polarisation mismatch, and 2.4 GHz Wi-Fi noise all reduce real range. Treat the result as an optimistic upper bound and apply a safety margin of 6-10 dB for practical flying. #### Israel Mortgage Calculator URL: https://geratools.com/israel-mortgage-calculator Models an Israeli home loan (mashkanta): computes the monthly repayment and total interest from price, deposit and rate, converts the loan to a monthly payment, and checks it against Bank of Israel LTV limits — 75% first home, 70% upgraders, 50% investors. How to use: 1. Enter the property price and deposit: Type the purchase price and the cash deposit (equity) you will put in, both in shekels. 2. Enter the rate and term: Type the annual interest rate and the loan term in years (commonly 25–30 in Israel). 3. Read the payment and LTV check: See the monthly repayment, total interest, and whether the loan-to-value stays within the Bank of Israel limit for your buyer type. FAQ: Q: What is the maximum LTV for a mortgage in Israel? A: The Bank of Israel caps the loan-to-value at 75% for a first-home buyer, 70% for someone upgrading (replacing their only home), and 50% for investors and additional-property buyers. The calculator checks your loan against the limit you select and warns if your deposit is too small. Q: How is the monthly mashkanta payment calculated? A: For the portion on a fixed rate, the tool uses the standard amortising formula: payment = L × r ÷ (1 − (1 + r)^−n), where L is the loan, r is the monthly rate (annual ÷ 12) and n is the number of months. Each payment is constant; early payments are mostly interest. Q: What is a typical mortgage term in Israel? A: Israeli mortgages commonly run 20 to 30 years, with 30 years the regulatory maximum. A longer term lowers the monthly payment but increases total interest. Lenders also stress-test affordability and usually require the payment to stay well below half of net household income. Q: Why is the Israeli mortgage so often a mix of tracks? A: Real mashkantot blend several maslulim (tracks) — prime-linked, fixed unindexed, and CPI-indexed — each with its own rate and risk. Bank of Israel rules require at least one third of the loan at a fixed rate. This calculator models a single blended rate for simplicity. Q: Does this include CPI indexation or fees? A: No. Many Israeli tracks are linked to the consumer price index, which raises the balance and payment over time, and there are also appraisal, legal and registration costs. This tool gives a clean fixed-rate estimate; ask your bank for the full tamhil including indexation. #### Kentucky Hourly to Salary Calculator URL: https://geratools.com/kentucky-hourly-to-salary-calculator Converts an hourly wage to gross annual salary, then estimates Kentucky take-home pay by applying the state's flat income tax, FICA, federal income tax, and any local occupational tax to show annual, monthly, and per-paycheck net pay. How to use: 1. Enter your hourly wage and hours: Type your hourly pay rate, the hours you work each week, and the number of weeks you work per year. 2. Add local occupational tax: Enter any city or county occupational (payroll) tax rate that applies where you work, such as Louisville or Lexington. 3. Read your take-home pay: The tool computes gross salary, then subtracts FICA, federal tax, Kentucky's flat tax, and local tax to show your net annual and per-paycheck pay. FAQ: Q: What is Kentucky's income tax rate? A: Kentucky uses a single flat income tax rate on taxable income with no graduated brackets — 4.0% for the 2024 and 2025 tax years, dropping to 3.5% from the 2026 tax year. After subtracting the state standard deduction, the same flat rate applies whether you earn 30,000 or 300,000 dollars per year. Q: Does Kentucky have a local payroll tax? A: Many Kentucky cities and counties levy a local occupational (payroll) tax on wages, often between 1% and 2.5%. Louisville and Lexington both have notable occupational taxes, so include your local rate for an accurate take-home estimate. Q: How do I convert hourly pay to an annual salary? A: Multiply your hourly wage by the hours you work per week, then by the weeks you work per year. For example, 25 dollars per hour at 40 hours a week for 52 weeks is 25 times 40 times 52, which equals 52,000 dollars gross per year. Q: What is deducted from a Kentucky paycheck? A: A Kentucky paycheck has FICA (6.2% Social Security up to the wage base plus 1.45% Medicare), federal income tax, the state's flat income tax after the standard deduction, and any local occupational tax. The remainder is your take-home pay. Q: Is this calculator exact? A: It is an estimate. It uses current FICA rates, federal brackets, and Kentucky's flat tax with a standard deduction, but it excludes 401(k) and pre-tax benefits, tax credits, and the 0.9% additional Medicare surtax. Verify with a payroll professional. #### Neonatal Jaundice Phototherapy Threshold Calculator URL: https://geratools.com/neonatal-jaundice-bilirubin-threshold Plot total serum bilirubin at a given postnatal age in hours against NICE gestational-age-specific phototherapy and exchange-transfusion thresholds, and see how far the value sits below or above each line. For neonatologists and NICU nurses. Runs in your browser. How to use: 1. Enter gestational age at birth: Select the completed weeks of gestation, which determines which NICE threshold curve applies. 2. Enter postnatal age and bilirubin: Provide the baby's age in hours since birth and the measured total serum bilirubin in micromoles per litre. 3. Read the action thresholds: The tool shows the phototherapy and exchange thresholds for that age and whether the measured value crosses either. FAQ: Q: Which thresholds does this use? A: It implements the NICE neonatal jaundice treatment thresholds, which give a phototherapy line and an exchange-transfusion line that rise with postnatal age and shift higher with greater gestational maturity. The lines are defined as treatment-threshold graphs for each gestation band. Q: Why does gestational age change the threshold? A: More premature babies have immature livers and blood-brain barriers, so they are at risk of bilirubin toxicity at lower levels. NICE therefore sets lower thresholds for earlier gestations and the highest thresholds at term, so the same bilirubin can be safe at 40 weeks but require treatment at 32. Q: How are the threshold lines shaped? A: Within the first day or two the threshold rises steeply with age in hours, then plateaus to a constant ceiling from roughly day three or four onward. This tool models that as a linear rise from a birth value up to the plateau, matching the NICE graph shape, then a flat line. Q: What should I do if bilirubin is above the line? A: A value at or above the phototherapy threshold indicates phototherapy should be started, and a value reaching the exchange line indicates preparation for exchange transfusion and urgent senior review. Always act on the official NICE chart and local protocol, not a single calculator output. Q: Is this a replacement for the NICE chart? A: No. It is a convenience tool that approximates the published threshold graphs so you can quickly see roughly where a value sits. The definitive decision must be made by plotting on the official age-specific NICE treatment threshold chart and applying clinical judgement. #### Oklahoma Workers' Compensation Premium Calculator URL: https://geratools.com/oklahoma-workers-comp-calculator Estimates an Oklahoma employer's annual workers' compensation premium using the standard formula of payroll per 100 dollars times the classification base rate times the experience modifier, so you can budget coverage cost by class code and headcount. How to use: 1. Enter annual payroll: Type the total annual payroll for the class of workers you are insuring, per classification code. 2. Enter the base rate: Input the workers' comp rate per 100 dollars of payroll for that class code, found on your policy or NCCI class table. 3. Set your experience modifier: Enter your experience mod (1.00 if you have none), and the calculator multiplies it through to estimate the annual premium. FAQ: Q: How is a workers' comp premium calculated? A: The standard formula is payroll divided by 100, multiplied by the class code base rate, multiplied by your experience modifier. The result is the annual manual premium before any schedule credits, discounts, or fixed expense constants. Q: What is a class code base rate? A: Each job type has a classification code (set by NCCI) with a rate expressed per 100 dollars of payroll. Office work might be under 0.30 dollars while roofing can exceed 15 dollars, reflecting the injury risk of the occupation. Q: What is an experience modifier? A: The experience modifier (mod) adjusts premium up or down based on your past claims history versus similar employers. A mod of 1.00 is average, below 1.00 earns a credit for good safety, and above 1.00 adds a surcharge for higher losses. Q: Is Oklahoma a monopolistic workers' comp state? A: No. Oklahoma has a competitive market where employers buy coverage from private carriers or the state-affiliated CompSource Mutual, and qualifying employers may self-insure. Rates and credits therefore vary by carrier within the same class code. Q: What does this estimate leave out? A: It computes the manual premium only. Actual policies add an expense constant, may apply premium discounts for size, schedule credits or debits, terrorism and assessment charges, and a minimum premium, so your quoted price can differ from this figure. #### Oxy-Acetylene Tip Size & Pressure Chart URL: https://geratools.com/oxy-acetylene-tip-chart Interactive chart matching steel thickness to the correct Victor-style tip number for cutting, welding, and heating, plus recommended oxygen and acetylene regulator pressures in PSI. Explains the neutral, oxidizing, and carburizing flame settings for torch setup. Runs in your browser. How to use: 1. Choose the operation: Select cutting, welding, or heating. Each operation uses different tips and pressures for the same plate thickness. 2. Enter the steel thickness: Type the plate thickness in inches. The chart selects the matching tip number and recommended pressures. 3. Read tip and pressures: The tool returns a Victor-style tip number with oxygen and acetylene regulator PSI, plus a reminder of the correct flame setting. FAQ: Q: What does the tip number mean? A: The tip number indexes the orifice size. Smaller numbers (0, 00) are tiny orifices for thin material; larger numbers (3, 4, 5) have bigger orifices that pass more gas to cut or heat thicker steel. Manufacturers like Victor, Harris, and Thermadyne number their tips on similar scales. Q: Why must I never exceed about 15 PSI on acetylene? A: Acetylene becomes chemically unstable and can decompose explosively above roughly 15 PSI in the free state. Always keep the acetylene regulator at or below 15 PSI. The chart never recommends acetylene pressures above this safety limit. Q: What is a neutral flame? A: A neutral flame has balanced oxygen and acetylene, shown by a single sharp inner cone with no feathery secondary cone. It is the standard for cutting and most welding. A carburizing (excess acetylene) flame shows a feather; an oxidizing (excess oxygen) flame is shorter and hissing. Q: Do cutting and welding use the same tips? A: No. Cutting uses a cutting attachment with a center preheat-and-oxygen tip designed to deliver a high-pressure oxygen stream that burns through the steel. Welding and heating use single-orifice tips that mix the gases for a soft flame. Always match tip type to operation. Q: Are these pressures exact? A: They are manufacturer-style starting points. Exact pressures vary by tip brand, hose length, and torch model, and should be set with the torch flowing, not static. Always consult your tip manufacturer's chart and adjust for a clean, stable flame. #### Partnership Profit Allocation Calculator URL: https://geratools.com/partnership-profit-allocation-calculator Implements partnership allocation logic — guaranteed payments first, then residual profit or loss split by agreed ratio — to allocate annual taxable income to each partner's capital account. CPAs and attorneys use it for K-1 prep and tax planning. How to use: 1. Enter net income before guaranteed payments: Type the partnership's net taxable income or loss for the year before deducting any guaranteed payments. 2. Set each partner's terms: Enter each partner's guaranteed payment and their residual profit or loss percentage that splits whatever remains. 3. Read each allocation: The tool deducts guaranteed payments, splits the residual by ratio, and shows each partner's total allocation for their K-1. FAQ: Q: What is a guaranteed payment? A: A guaranteed payment is compensation to a partner for services or use of capital that is fixed regardless of partnership income, similar to a salary. It is deducted before residual profit is split and is reported to the partner as ordinary income on the K-1, separate from their distributive share. Q: How is the residual profit calculated? A: Residual profit or loss equals net income minus the sum of all guaranteed payments. That residual is then allocated to each partner by their agreed residual percentage. A partner can have a residual loss even while receiving a positive guaranteed payment. Q: Do the residual percentages need to total 100 percent? A: Yes, for a complete allocation they should sum to 100 percent so the entire residual is allocated. The tool shows the total and flags it if the percentages do not add up so you can correct the agreement figures before relying on the result. Q: What if the partnership has a loss? A: Guaranteed payments are still paid and deducted, which usually deepens the residual loss. The negative residual is allocated by the same ratios, so partners can show a net negative allocation. Loss deductibility for each partner depends on basis and at-risk rules outside this tool. Q: Is this a substitute for tax preparation? A: No. It models the allocation mechanics for planning and K-1 review. Special allocations, Section 704(b) capital-account maintenance, and basis limitations require a tax professional and proper partnership accounting. #### Predicted Peak Expiratory Flow Calculator URL: https://geratools.com/predicted-peak-flow Compute predicted peak expiratory flow rate from age, sex, and height using the Nunn-Gregg EU/EN13826 reference equations, then express a measured PEFR as percent predicted. For respiratory nurses and asthma management. Runs in your browser. How to use: 1. Enter age, sex, and height: Provide the patient's age in years, biological sex, and height in centimetres. 2. Optionally enter a measured PEFR: If you have a reading from an EU-scale peak flow meter, type it in litres per minute to get a percent-predicted figure. 3. Read the predicted value: The tool returns the predicted PEFR for that profile and, if a measurement is given, the percent of predicted achieved. FAQ: Q: Which reference equation does this use? A: It uses the Nunn and Gregg equations, the standard for EU-scale (EN13826) peak flow meters used across the UK and Europe. They are exponential equations in age and height with separate constants for men and women, and they replaced the older Wright-scale norms. Q: Why does the meter scale matter? A: Old Wright-scale meters and newer EU-scale meters give different readings for the same lungs because of how they were calibrated. The Nunn-Gregg equations are matched to EU-scale meters, so your measured value should come from an EU-scale device for the percent-predicted comparison to be valid. Q: What is a normal percent predicted? A: Values within roughly 80 to 100 percent of predicted are generally considered normal. In asthma management, readings of 50 to 80 percent often indicate a moderate exacerbation and below 50 percent a severe one, though personal best is a better individual reference than the population predicted value. Q: Does this work for children? A: The Nunn-Gregg adult equations are validated for adults, broadly from the late teens upward. Children have their own height-based reference equations, so for paediatric patients you should use a dedicated childhood peak flow chart rather than these adult formulas. Q: Should I rely on predicted or personal best? A: For ongoing asthma monitoring, a patient's own personal best, measured when well, is the preferred reference because peak flow varies between individuals of the same age and height. The predicted value is most useful as a first estimate before a personal best is established. #### Prejudgment Interest Calculator URL: https://geratools.com/prejudgment-interest-calculator Calculates interest on a damages principal from the date of loss or filing to the expected judgment date using a state-specific statutory rate. Commercial litigators and economic-damage experts use it to quantify prejudgment interest for trial. How to use: 1. Enter the damages principal: Type the amount of damages on which interest accrues — typically the economic loss as of the accrual date. 2. Pick a state rate and the accrual basis: Choose a state to load its statutory prejudgment rate, or enter a custom rate, and select simple or annual compounding as that state requires. 3. Set accrual and judgment dates: Enter the date of loss or filing and the expected judgment date. The tool counts the days and shows total accrued interest plus the principal-plus-interest total. FAQ: Q: What is prejudgment interest? A: Prejudgment interest compensates a plaintiff for the time value of money lost between the date the harm occurred (or the suit was filed) and the date of judgment. It is awarded on top of the underlying damages to make the plaintiff whole. Q: Is prejudgment interest simple or compound? A: It depends entirely on the jurisdiction. Many states mandate simple interest at a fixed statutory rate, while others allow annual compounding. This tool lets you choose, but you must confirm the rule for your specific state and claim type. Q: What rate should I use? A: Each state sets its own statutory prejudgment interest rate, and some tie it to a treasury or judgment rate that changes annually. The built-in rates are common defaults; for an actual case, verify the current statutory rate against the controlling statute. Q: When does interest start accruing? A: The accrual date varies by jurisdiction and claim type. It may be the date of the breach or injury, the date the loss became fixed, or the date the complaint was filed. Choosing the wrong start date materially changes the award, so confirm the rule. Q: Is this a substitute for an expert calculation? A: No. Prejudgment interest rules are highly jurisdiction-specific and can involve segmented rates, partial-year proration, and offsets. Use this as a quick estimate and have a damages expert or counsel confirm the figure for trial. #### Promissory Note Amortization Calculator URL: https://geratools.com/promissory-note-amortization-calculator Produces a month-by-month amortization table showing principal, interest, balance, and total paid for fixed-rate, interest-only, or balloon promissory notes. Real estate attorneys, lenders, and borrowers use it to verify note terms and track balance. How to use: 1. Enter principal, rate, and term: Type the note's principal amount, annual interest rate, and the amortization term in months or years. 2. Choose the payment structure: Pick fully amortizing, interest-only, or balloon, and for a balloon set the number of months before the lump sum is due. 3. Read the schedule: The tool computes the monthly payment and a full table of principal, interest, and running balance, plus total interest paid. FAQ: Q: How is the monthly payment calculated? A: For a fully amortizing note the payment uses the standard formula P × r / (1 − (1 + r)^−n), where r is the monthly rate and n the number of payments. This produces a level payment that pays the note to zero over the term. Interest-only notes pay only the monthly interest until the principal is due. Q: What is a balloon payment? A: A balloon note is amortized over a long schedule but the full remaining balance is due as a lump sum after a shorter period. The monthly payment is based on the long amortization, keeping payments low, while the balloon repays the large remaining balance at the balloon date. Q: Why does early in the schedule pay mostly interest? A: Interest each month is charged on the outstanding balance, which is highest at the start. Since the payment is level, more of it goes to interest early on and progressively more to principal as the balance falls. This front-loading of interest is normal for amortizing debt. Q: How is interest-only different? A: An interest-only note pays just the accrued interest each month, so the balance never falls during the interest-only period and the full principal remains due at maturity. Payments are lower but no equity is built until the principal is repaid. Q: Is daily versus monthly interest handled? A: This tool uses standard monthly compounding, which is the most common convention for promissory notes and is how most amortization schedules are quoted. Notes that accrue daily or use a 365/360 convention will differ slightly; confirm the accrual basis in the note itself. #### Singapore Personal Loan Calculator URL: https://geratools.com/singapore-personal-loan-calculator Calculate monthly instalments, total interest and a full amortisation schedule for a Singapore personal loan using the effective interest rate (EIR), the true cost banks must disclose. Reflects local EIR norms of 3.5-10%. Runs in your browser. How to use: 1. Enter the loan amount: Type how much you want to borrow. Singapore banks usually lend personal loans of a few thousand up to several times your monthly income. 2. Set the EIR and tenure: Enter the effective interest rate (EIR) the lender quotes and the tenure in years. Use the EIR, not the lower flat advertised rate, for an accurate result. 3. Read repayments and schedule: See your monthly instalment, total interest, total repaid, and a month-by-month amortisation table splitting interest from principal. FAQ: Q: What is the EIR and why use it? A: The effective interest rate (EIR) is the true annual cost of a loan including how the balance reduces over time, and Singapore lenders are required to disclose it. The advertised flat rate looks lower because it ignores the falling balance. Always model with the EIR for an accurate instalment. Q: How is the monthly instalment calculated? A: The tool uses the standard amortising annuity formula. The monthly rate is the EIR divided by 12, and the instalment is the loan times that rate divided by one minus (1 plus the monthly rate) to the power of minus the number of months. Each payment is equal. Q: What rates do Singapore personal loans charge? A: Bank personal loans typically carry an EIR of roughly 3.5% to 10% per year depending on your profile. Licensed moneylenders are legally capped at 4% interest per month. Always compare on EIR rather than headline flat rate. Q: Why does early interest look so high in the schedule? A: Interest is charged on the outstanding balance, which is largest at the start. So early instalments are mostly interest and little principal. As the balance falls, more of each fixed payment goes to principal — that is how amortisation works. Q: Does this include processing fees or insurance? A: No. It models pure principal and interest from the EIR you enter. Processing fees, late charges and optional insurance are excluded, so a real loan may cost a little more. Check the lender's full fact sheet before signing. #### South Africa Mortgage Calculator URL: https://geratools.com/south-africa-mortgage-calculator Models a South Africa home loan using local norms — prime-linked variable rates (prime ~11.75%), deposit/LTV requirements and typical 20-year terms — to produce the monthly bond repayment, total interest, and an affordability stress test. How to use: 1. Enter property price and deposit: Type the purchase price and your cash deposit. The tool computes the loan amount and loan-to-value (LTV) ratio. 2. Set the rate and term: Enter your annual interest rate (most SA bonds are prime-linked, around prime ±0%) and the term in years, typically 20. 3. Read your repayment: The tool returns the monthly bond repayment, total repaid, total interest, and a stress test at a higher rate to gauge affordability. FAQ: Q: How is a South Africa bond repayment calculated? A: The standard amortising loan formula is used: M = P·r·(1+r)^n / ((1+r)^n − 1), where P is the loan amount, r is the monthly rate (annual rate ÷ 12), and n is the number of monthly payments (years × 12). This is the same maths every SA bank applies to a home loan. Q: What rate should I use? A: Most South African home loans are variable and quoted relative to the prime lending rate, which has been around 11.75%. A strong applicant may secure prime or below; others pay prime plus a margin. Use the rate your bank quotes, and check the stress-test figure for room if prime rises. Q: Do I need a deposit? A: Banks often lend up to 100% LTV for qualifying buyers, but a deposit of 10% to 20% lowers your loan, monthly payment and total interest, and usually earns a better rate. First-time-buyer 100% bonds exist but cost more over the term. Q: Why does the tool show a stress test? A: South African bond rates are variable, so a rate increase raises your payment immediately. The stress test recomputes the repayment at a rate two percentage points higher so you can check you could still afford the bond if prime climbs. Q: Does this include other ownership costs? A: No. The repayment covers principal and interest only. Budget separately for transfer duty and bond registration costs at purchase, plus ongoing rates, levies (for sectional title), insurance and maintenance. #### UAE Personal Loan Calculator URL: https://geratools.com/uae-personal-loan-calculator Free UAE personal loan calculator. Enter the amount, rate and term to see your monthly instalment, total interest, and a full amortisation schedule. Covers reducing-balance and flat-rate quotes common in the UAE. Runs in your browser. How to use: 1. Enter the loan amount and term: Type how much you want to borrow in AED and the term in months. 2. Choose the rate type: Pick reducing-balance (the true APR that the UAE Central Bank requires banks to quote) or flat rate, and enter the advertised percentage. 3. Read the repayment: See your monthly instalment, total interest, total repayable, and an amortisation breakdown. FAQ: Q: How are UAE personal loan repayments calculated? A: On a reducing-balance basis the monthly instalment uses the standard amortising formula M = P·r(1+r)ⁿ / ((1+r)ⁿ−1), where r is the monthly rate and n the number of months. Interest each month is charged only on the outstanding balance, which falls as you repay. Q: What is the difference between flat rate and reducing-balance rate? A: A flat rate charges interest on the original principal for the whole term, so a 5% flat rate is much more expensive than 5% reducing-balance. UAE banks often advertise flat rates but the Central Bank requires the equivalent reducing-balance APR (EIR) to be disclosed — always compare on that basis. Q: How high are UAE personal loan rates? A: Reducing-balance rates typically run from about 6% to 12% APR depending on your salary, employer, and whether the bank holds your salary transfer. The Central Bank of the UAE caps personal loan pricing and limits instalments to a share of your income. Q: How much can I borrow in the UAE? A: Central Bank rules cap most personal loans at around 20 times your monthly salary and require the loan to be repaid within 48 months for salary-based lending. Total monthly debt repayments are also limited to roughly half of your income. Q: Does this calculator store my data? A: No. All figures are computed locally in your browser and nothing is uploaded, so your loan details stay private. #### Sales Commission Calculator URL: https://geratools.com/sales-commission-calculator Free sales commission calculator. Enter total sales and a commission rate to get earnings, or add a base salary for total pay. Runs entirely in your browser — nothing is uploaded. How to use: 1. Pick a structure: Choose a flat commission rate, or base salary plus commission. 2. Enter your numbers: Type your total sales and commission rate, plus a base salary if relevant. 3. Read your earnings: The commission and total pay update instantly below. FAQ: Q: How is sales commission calculated? A: Multiply total sales by the commission rate as a decimal. For example, 25,000 in sales at an 8% rate gives 25,000 x 0.08 = 2,000 in commission. Q: Can I include a base salary? A: Yes — switch to the base salary plus commission mode and the tool adds your base draw to the calculated commission for total pay. Q: Is my data uploaded anywhere? A: No — every calculation runs locally in your browser and nothing is sent to a server. Q: What commission rate is typical in sales? A: It varies widely by industry. Many roles fall between 5% and 15% of revenue, with high-ticket or SaaS deals sometimes higher and volume retail lower. This tool lets you enter whatever rate your plan specifies. Q: How do I calculate base salary plus commission? A: Add your fixed base draw to the commission. For example, a £1,500 monthly base plus 8% on £25,000 of sales is 1,500 + 2,000 = £3,500 total pay. Q: Is commission calculated on revenue or profit? A: This calculator multiplies the rate by the sales figure you enter, so it works for either — just enter revenue for a revenue-based plan or gross margin for a margin-based plan. Q: How do I find the commission rate from earnings? A: Divide the commission earned by total sales and multiply by 100. Earning £2,000 on £25,000 of sales is 2,000 ÷ 25,000 × 100 = 8%. #### Savings Goal Tracker URL: https://geratools.com/savings-goal-tracker Free savings goal tracker. Set multiple targets and deadlines, log deposits, see progress bars and a 3-year projection chart, and learn exactly how much to save each month. 100% private — runs in your browser. How to use: 1. Add each savings goal: Enter a name, target amount, how much you have saved so far, your planned monthly contribution and an optional deadline. 2. Log deposits as you go: Use the add/withdraw box on each goal card to record real deposits (or withdrawals with a minus sign); the progress bar and chart update instantly. 3. Read the projection and adjust: The stacked chart shows when each goal is funded; if a goal is flagged BEHIND, raise its monthly amount until it shows ON TRACK for its deadline. FAQ: Q: How does the savings goal tracker work? A: For every goal you enter a target, your current balance, a monthly contribution and an optional deadline. The tool divides the remaining amount by your monthly contribution to estimate a finish date, draws a progress bar for each goal, and stacks all goals into a single projection chart so you can see your whole plan funding over the next three years. Q: Can I track more than one savings goal at once? A: Yes — that is the whole point. Add as many goals as you like (emergency fund, holiday, car, house deposit, gadgets) and each gets its own colour, progress bar and finish-date estimate. A combined progress bar and projection chart show your overall picture across every goal at once. Q: How much should I save each month to hit my deadline? A: When you set a deadline, the tracker shows the exact required monthly amount: remaining balance divided by the number of whole months left. If your planned monthly contribution is below that figure the goal is flagged BEHIND, so you know to either save more or move the date. Q: What do the ON TRACK and BEHIND labels mean? A: ON TRACK means your planned monthly contribution will reach the target on or before the deadline. BEHIND means it will not — either the monthly amount is too low or there is no monthly amount set. Goals with no deadline are never flagged because there is nothing to be behind against. Q: Is my financial data sent anywhere? A: No. Every number stays in your browser. Goals are saved to local storage on your own device so they are still there when you come back, and nothing is ever uploaded to a server. You can export a CSV at any time for your own records. Q: Can I export my goals or move them to another device? A: You can export all goals to a CSV file with one click, including target, saved, remaining, progress percentage, monthly plan, deadline and whether each goal is on track. Because data is stored locally, opening the page on a different browser or device starts fresh, so use the CSV export to keep a copy. #### Invoice Tracker URL: https://geratools.com/invoice-tracker Free invoice tracker for freelancers and small businesses. Log invoices with client, amount and due date, see paid/unpaid/overdue status, totals and outstanding balance, and export to CSV. 100% in your browser — nothing is uploaded. How to use: 1. Add each invoice: Click New invoice and enter the client, amount, currency, issue date and due date. Mark it unpaid to start. 2. Mark invoices paid as money arrives: Hit the tick button on a row to flip it to paid; anything still unpaid past its due date turns red as overdue automatically. 3. Watch your outstanding total: The summary cards show billed, paid and outstanding per currency so you always know how much is owed to you. 4. Export to CSV: Filter to all, unpaid or overdue, then click Export CSV to download a spreadsheet-ready file for your accountant. FAQ: Q: How does the tracker decide an invoice is overdue? A: Any invoice still marked unpaid whose due date is earlier than today is shown as overdue automatically. You never set overdue yourself — it is derived from the due date, so the status stays correct as time passes. Marking the invoice paid clears it. Q: Where is my invoice data stored? A: Everything is saved in your browser using localStorage. No invoice, client name or amount is ever sent to a server. The trade-off is that data lives on this one device and browser, so export to CSV regularly if you want a backup or need it elsewhere. Q: Can I track invoices in more than one currency? A: Yes. Each invoice has its own currency, and the summary cards group totals by currency so a GBP book and a USD book never get added together. This keeps your outstanding figures honest when you bill international clients. Q: What is included in the CSV export? A: The export contains the invoice number, client, amount, currency, issue date, due date, effective status (paid, unpaid or overdue), days until due and your notes. It exports whatever is currently filtered, so you can download just the overdue invoices to chase. Q: How is this different from an invoice generator? A: An invoice generator creates the document you send to a client. This tracker is the other half: it manages the invoices you have already sent, telling you what is still owed, what is overdue and your total receivables. Use the generator to bill and the tracker to get paid. Q: Does it calculate tax or VAT? A: No. The tracker records the final invoice amount you bill — whatever figure appears on the document, including any tax. It focuses on receivables and ageing rather than recalculating tax, so enter the gross total of each invoice. #### Sinking Fund Planner URL: https://geratools.com/sinking-fund-planner Free sinking fund planner. Add multiple savings goals with a target amount and date, and it works out the monthly, weekly and daily contribution for each — plus totals and a budget check. Runs entirely in your browser; nothing is uploaded. How to use: 1. Add each savings goal: Give every goal a name, a target amount and the date you want the money by. 2. Enter what you have saved: Type the amount already put aside for each goal so the planner only spreads the remaining balance. 3. Read the monthly contribution: The planner shows how much to save per month, week and day for each goal, plus the combined total across all goals. 4. Check it against your budget: Enter an optional monthly savings budget and the planner tells you whether your plan fits or by how much you are short. FAQ: Q: What is a sinking fund? A: A sinking fund is money you deliberately set aside, a little at a time, for a known future expense — a holiday, a car, an annual insurance bill, Christmas, or an emergency buffer. Instead of being surprised by a large cost, you spread it across the months leading up to it so the money is ready when you need it. Q: How does the planner work out the monthly contribution? A: For each goal it subtracts what you have already saved from the target to get the remaining balance, counts the whole months between today and your target date, then divides the remaining balance by that number of months. The weekly and daily figures use the exact number of days left, so they stay accurate even for short deadlines. Q: Can I plan several goals at once? A: Yes — that is the point. Add as many goals as you like, each with its own target, date and priority. The planner sums every monthly contribution into one combined figure so you can see the full monthly cost of all your savings plans together, not just one in isolation. Q: What does the monthly budget check do? A: If you enter an optional monthly savings budget, the planner compares it against the total of all your goal contributions. It shows green with the spare amount if your budget covers everything, or red with the shortfall if it does not — a quick reality check before you commit to dates you cannot meet. Q: Does it account for interest earned on the savings? A: No. This planner uses simple, flat contributions and assumes no interest or investment growth, which keeps the targets conservative and easy to hit. For interest-bearing or invested goals, pair it with a compound interest calculator: any growth you earn becomes a buffer that helps you reach the target sooner. Q: Is my financial information private? A: Completely. Every figure is calculated in your browser and your goals are saved only in this browser using local storage. Nothing is ever uploaded to a server, and you can clear everything with one click at any time. #### FIRE Number Calculator URL: https://geratools.com/fire-number-calculator Free FIRE number calculator. Enter your annual expenses and a safe withdrawal rate to get your financial-independence target, then see years-to-FI from your savings rate, expected return and current portfolio. Runs entirely in your browser. How to use: 1. Enter your annual expenses: Type what you expect to spend each year once you stop working. This drives the whole target. 2. Set a safe withdrawal rate: Pick the percentage you plan to draw each year — 4% is the classic rule of thumb. The tool divides expenses by this rate to get your FIRE number. 3. Add your savings and growth assumptions: Enter your current invested savings, your savings rate or fixed yearly contribution, and an expected real return. The chart and table show the year you cross the target. FAQ: Q: What is a FIRE number? A: Your FIRE number is the size of invested portfolio that lets you live off withdrawals indefinitely. It is your annual expenses divided by your safe withdrawal rate. At a 4% rate, that is 25 times your yearly spending. Q: How is the FIRE number calculated? A: FIRE number = annual expenses divided by (withdrawal rate / 100). For example, 30,000 of expenses at a 4% withdrawal rate gives 30,000 / 0.04 = 750,000. Lowering the withdrawal rate raises the target because you are drawing a smaller slice each year. Q: What is a safe withdrawal rate? A: It is the percentage of your portfolio you withdraw in the first year of retirement, then adjust for inflation. The 4% rule comes from the Trinity study and is a common starting point, but many people choose 3% to 3.5% for a longer horizon or a lower-return outlook. Q: How does my savings rate affect years to independence? A: Savings rate is the single biggest lever. A higher rate both shrinks the spending you need to cover and grows your portfolio faster, so years-to-FI fall sharply. The calculator projects your balance forward each year until it reaches the target. Q: What is the difference between Lean, standard and Fat FIRE? A: Lean FIRE assumes a leaner lifestyle — here modelled at 70% of your stated expenses. Standard FIRE uses your actual expenses. Fat FIRE targets a more comfortable lifestyle, modelled at 150% of expenses, which needs a larger portfolio. Q: Should I use a real or nominal return? A: Use a real (after-inflation) return, because your expenses and FIRE number are in today money. A common real-return assumption for a diversified stock-heavy portfolio is 4% to 5%. Using a nominal return would overstate how quickly you reach a target expressed in today prices. #### Inflation Calculator URL: https://geratools.com/inflation-calculator Free inflation calculator. Enter an amount, a start and end year and an average inflation rate to see the equivalent value, total inflation and lost purchasing power — with a chart and year-by-year table. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter the amount and currency: Type the sum of money you want to compare across years and pick a currency (or any neutral symbol). 2. Set the start year, end year and average rate: Enter the year your amount is measured in, the year you want to translate it to, and an average annual inflation rate. 3. Read the equivalent value and lost buying power: See what the amount is worth in the other year, the total inflation over the period, and how much purchasing power was lost — plus a chart and year-by-year table. FAQ: Q: How does this inflation calculator work? A: It compounds your chosen average annual rate over the gap between the two years. The number of years n is end year minus start year, the inflation factor is (1 + rate) raised to the power n, and the equivalent value is your amount multiplied by that factor. Buying power is your amount divided by the same factor. Q: What is the difference between equivalent value and buying power? A: Equivalent value restates your amount in the other year's money, so it rises with inflation: 1,000 in an earlier year is worth more nominal currency later. Buying power is the mirror image — it shows what the same nominal sum actually buys, expressed in start-year terms, so it falls. Both come from the one inflation factor. Q: What is cumulative inflation? A: Cumulative inflation is the total price rise across the whole period, not the yearly rate. Because inflation compounds, 3% a year for 20 years adds up to about 81% in total, not 60%. The calculator shows this as the total inflation figure and per-year in the table. Q: What average inflation rate should I use? A: Many central banks target around 2 to 3 percent a year, so that is a common long-run assumption. For a specific historical span, look up the official consumer price index figures for your country and enter the average annual rate over that period. You can model any rate, including high-inflation scenarios. Q: Can I go backwards in time? A: Yes. If you set the end year earlier than the start year the calculator counts backwards, so it tells you what a later sum was worth in earlier money. The factor simply uses a negative number of years, which divides instead of multiplies. Q: Does this use live or official inflation data? A: No. Every figure comes from the single average rate you type in, so you stay in control of the assumption and nothing depends on a network connection. It never fetches live indices, and nothing you enter is uploaded or stored on a server. #### Annuity Calculator URL: https://geratools.com/annuity-calculator Free annuity calculator: find present value (PV), future value (FV), or the periodic payment for ordinary annuities and annuities-due. Supports monthly, quarterly, annual and five other frequencies. Runs entirely in your browser — no data is uploaded. How to use: 1. Choose what to calculate: Pick one of four modes: find Present Value, find Future Value, find the payment given a PV (loan repayment), or find the payment given a FV (savings goal). 2. Select ordinary annuity or annuity-due: Ordinary annuities pay at the end of each period (most loans, bonds). Annuities-due pay at the start (some leases, insurance premiums). The calculator adjusts all formulae automatically. 3. Enter the known values: Type the payment amount (or loan/savings amount), the annual interest rate, the term in years, and how often payments occur — annual, semi-annual, quarterly, monthly, bi-weekly, or weekly. 4. Read the results and payment schedule: The tool shows PV, FV, payment per period, total paid, total interest, and the interest-to-principal ratio. Click "Show payment schedule" for a full period-by-period breakdown. FAQ: Q: What is the formula for the present value of an ordinary annuity? A: PV = PMT x [1 - (1+r)^(-n)] / r, where PMT is the periodic payment, r is the periodic interest rate (annual rate divided by number of periods per year), and n is the total number of periods. For an annuity-due (payments at start of period) multiply the result by (1+r). Q: What is the difference between an ordinary annuity and an annuity-due? A: An ordinary annuity makes payments at the end of each period — most mortgages, car loans and coupon bonds work this way. An annuity-due makes payments at the start of each period, which is common for rent, insurance premiums and some leases. Because an annuity-due receives each payment one period earlier, its present value is always higher by a factor of (1+r) compared with an otherwise identical ordinary annuity. Q: How do I use this to calculate a loan repayment? A: Select "Find Payment (given Present Value)" mode, enter the loan amount as the Present Value, your annual interest rate, the term in years, and your payment frequency (usually monthly). The calculator returns the periodic payment — this is the standard amortising-loan payment formula PMT = PV x r / [1 - (1+r)^(-n)]. Q: How do I calculate how much I need to save each month to reach a goal? A: Select "Find Payment (given Future Value)" mode and enter your savings target as the Future Value. The calculator solves PMT = FV x r / [(1+r)^n - 1] (ordinary annuity) or divides by (1+r) for annuity-due, giving you the exact periodic deposit required. Q: What does the payment schedule show? A: Each row shows the period number, the fixed payment, how much of that payment is interest (balance times the periodic rate), how much reduces the principal (or increases the savings balance), and the running balance. For a loan the balance falls to zero; for a savings annuity the balance grows to the target Future Value. Q: Is my data private? A: Yes. All calculations run in your browser using JavaScript. No figures are sent to a server or stored anywhere. You can use the calculator offline once the page has loaded. #### Bond Price Calculator URL: https://geratools.com/bond-price-calculator Free bond price calculator. Enter face value, coupon rate, maturity and YTM to get the fair price, or enter a market price to back-solve the yield-to-maturity. Also shows Macaulay duration, modified duration, convexity and price sensitivity. Runs entirely in your browser. How to use: 1. Choose your calculation mode: Toggle between 'Solve for Price' (enter a target YTM to get the fair price) and 'Solve for YTM' (enter the market price to back-solve the yield). 2. Enter the bond parameters: Type the face (par) value, the annual coupon rate as a percentage, years to maturity, and the coupon payment frequency: annual, semi-annual or quarterly. 3. Enter YTM or market price: In Price mode enter the required yield; in YTM mode enter the price at which the bond currently trades. 4. Read the results: The calculator shows price, YTM, current yield, total income, Macaulay and modified duration, convexity, and the estimated price change for a one-percentage-point yield shift in either direction. 5. Copy the report: Use the Copy button to paste a full summary into a spreadsheet or document. FAQ: Q: What is the bond pricing formula? A: A coupon bond is priced as the present value of all its future cash flows: P = C x [1 - (1+r)^(-n)] / r + F x (1+r)^(-n), where C is the periodic coupon payment (annual coupon / frequency), r is the periodic yield (YTM / frequency), n is the total number of periods, and F is the face value. When the coupon rate equals the YTM the bond trades at par; when the YTM is above the coupon rate the bond trades at a discount; when below, at a premium. Q: How is yield-to-maturity calculated from a market price? A: There is no closed-form solution for YTM given price — it must be solved numerically. This calculator uses Newton-Raphson iteration (up to 200 steps) with a bisection fallback to find the periodic yield r such that the present-value formula reproduces the observed market price to within a tolerance of 0.000001. Q: What is Macaulay duration and why does it matter? A: Macaulay duration is the weighted-average time (in years) until you receive each cash flow, where each weight is that payment's present value as a fraction of the total bond price. A bond with a 7-year Macaulay duration will reprice as if all its cash flow arrives in year 7. It is the cornerstone metric for matching asset and liability cash flows in immunisation strategies. Q: What is modified duration? A: Modified duration = Macaulay duration / (1 + r_periodic). It measures approximate percentage price sensitivity: if modified duration is 6 and the yield rises by 1%, the bond price falls by about 6%. The approximation is improved by adding the convexity correction, which the calculator does automatically in the +/- 1% scenario rows. Q: What is convexity and why is it important? A: Convexity captures the curvature in the price-yield relationship. Duration alone gives a linear approximation; for large yield moves the error is significant. Adding the convexity term (0.5 x Convexity x (delta_y)^2 x Price) improves the estimate. Positive convexity (all plain-vanilla coupon bonds have it) means prices rise more than duration predicts when yields fall, and fall less than duration predicts when yields rise — a favourable asymmetry. Q: What is the difference between clean and dirty price? A: The clean price is what is quoted in the market and what this calculator computes. The dirty price (settlement price) adds accrued interest: the fraction of the next coupon that has built up since the last payment date. Between coupon dates the buyer pays the seller the accrued interest as compensation for the coupon income they will not receive. At a coupon payment date the two prices are equal. #### Bond Yield Calculator URL: https://geratools.com/bond-yield-calculator Free bond yield calculator. Enter a market price to get the yield to maturity (YTM), or enter a YTM to price a bond. Also shows Macaulay duration, modified duration, convexity, DV01 and a full coupon cash-flow schedule. Runs entirely in your browser. How to use: 1. Choose what you want to solve for: Select 'YTM given price' to find the yield on a bond you can buy at a known market price, or 'Price given YTM' to value a bond at a target yield. 2. Enter the bond parameters: Set the face (par) value, annual coupon rate, years to maturity, and coupon payment frequency (semi-annual is most common for government and corporate bonds). 3. Enter the market price or YTM: Type the clean market price in dollars (e.g. 950 for a $1,000 par bond trading at 95), or type the target YTM in percent. 4. Read the results: The calculator shows YTM, current yield, Macaulay and modified duration, convexity, and DV01 — the dollar change per one basis-point yield move. 5. Explore sensitivity and cash flows: Expand the sensitivity table to see how a 50 bp or 100 bp yield shift moves the price. Expand the cash-flow schedule to see every coupon and its present value. FAQ: Q: What is yield to maturity (YTM)? A: YTM is the single constant annual interest rate that, when used to discount all future coupon payments and the par repayment, exactly equals the bond's current market price. It is the internal rate of return (IRR) of buying the bond today and holding it to maturity. Because the formula has no closed-form inverse, this calculator solves for YTM using Newton-Raphson iteration with a bisection fallback — typically converging in under 20 steps. Q: How is bond price calculated from a given YTM? A: The standard formula is: P = C * [1 - (1+y)^(-n)] / y + FV * (1+y)^(-n), where C is the coupon per period (annual coupon / payments per year), y is the periodic YTM (annual YTM / payments per year), n is the total number of coupon periods, and FV is the face value. The first term is the present value of all coupons (an annuity) and the second term is the present value of the face repayment. Q: What is the difference between current yield and YTM? A: Current yield is simply the annual coupon divided by the current market price. It ignores both the time value of money and any capital gain or loss from buying the bond at a discount or premium to par. YTM accounts for all future cash flows and their timing, making it the better measure of total return. For a par bond the two are equal; for a discount bond YTM exceeds current yield; for a premium bond YTM is lower than current yield. Q: What is modified duration and why does it matter? A: Modified duration (ModD) measures how sensitive a bond's price is to a small change in yield. Specifically, the percentage price change is approximately equal to -ModD times the change in yield (in decimal form). A bond with modified duration 7 will lose about 7% in price if yields rise 1% (100 basis points). It equals Macaulay duration divided by (1 + y), where y is the periodic yield. Investors use it to compare interest-rate risk across bonds with different maturities and coupons. Q: What is convexity and when does it matter? A: Convexity measures the curvature of the price-yield relationship. A straight line (duration alone) underestimates price gains when yields fall and overestimates price losses when yields rise. Adding the convexity term gives a better approximation: dP/P ≈ -ModD * dy + 0.5 * Cx * dy^2. Convexity is always positive for plain vanilla bonds, so bonds with higher convexity outperform lower-convexity bonds of the same duration when yields move significantly. Q: What is DV01 (dollar value of a basis point)? A: DV01 (also called PVBP — price value of a basis point) is the dollar change in a bond's price for a one-basis-point (0.01%) move in yield. It equals ModD times price times 0.0001. Traders use DV01 to hedge interest-rate risk precisely. For example, if a bond has DV01 of $75, a 10 bp yield increase costs $750 in market value per bond. #### NPV Calculator URL: https://geratools.com/npv-calculator Free NPV calculator. Enter a discount rate and up to 40 cash flows to get Net Present Value, Internal Rate of Return (via bisection), payback period, discounted payback and a complete DCF schedule. 100% client-side — nothing is uploaded. How to use: 1. Set your discount rate (hurdle rate): Enter the required rate of return — for example 10 for 10% per year. This is also called the cost of capital or WACC. 2. Enter your initial investment at Period 0: Type a negative number for the upfront outlay, such as -100000 for a £100,000 investment made today. 3. Add expected cash flows for each future period: Click "Add period" and type the net cash inflow (positive) or outflow (negative) expected at the end of each period. 4. Read the NPV verdict: A positive NPV means the project earns more than the hurdle rate and should be accepted. A negative NPV means it destroys value at that rate. 5. Check IRR and payback: Compare the IRR to your hurdle rate — IRR above hurdle rate = accept. Payback shows how many periods until your cash position breaks even. FAQ: Q: What is Net Present Value (NPV)? A: NPV is the sum of all project cash flows discounted back to today at a chosen rate. A positive NPV means the project earns more than its cost of capital and creates value; a negative NPV means it earns less. The formula is NPV = sum of CF_t divided by (1 + r) to the power t, for each period t from 0 to n. Q: What discount rate should I use? A: Use your cost of capital — the return your investors or lenders expect. For a company this is often the Weighted Average Cost of Capital (WACC). A common shortcut is to use an industry benchmark (7–12% for listed equities in developed markets) or the risk-free rate plus a project-specific risk premium. The calculator lets you test multiple rates in seconds. Q: How is the IRR calculated? A: The Internal Rate of Return is the discount rate at which NPV equals zero. This tool uses bisection: it brackets the root between -99.99% and 1000%, then halves the interval 200 times until convergence to within 1e-10. Bisection always converges when a sign change exists and requires no initial guess. Be aware that unconventional cash flows (more than one sign change) can produce multiple IRRs — NPV is more reliable in those cases. Q: What is the difference between payback period and discounted payback? A: Simple payback counts the time until the raw (undiscounted) cumulative cash flow first reaches zero — it ignores the time value of money. Discounted payback does the same with each flow first divided by (1 + r)^t, so it reflects the real economic break-even. Discounted payback is always equal to or longer than simple payback. Q: What does the Profitability Index (PI) mean? A: PI = (NPV + initial outlay) / initial outlay, equivalently the ratio of the present value of future inflows to the initial cost. PI greater than 1 means accept; less than 1 means reject. PI is especially useful when ranking mutually exclusive projects with different scales — a smaller project with PI 1.8 may rank above a larger project with PI 1.2 under a capital constraint. Q: Can I model quarterly or monthly cash flows? A: Yes. Select "Quarter" or "Month" from the Period dropdown. The discount rate you enter is then the rate per quarter or per month. To convert an annual rate to a monthly rate, use (1 + annual rate)^(1/12) - 1. For example, 10% per year = (1.10)^(1/12) - 1 = 0.797% per month. Q: Is my data private? A: Completely. All calculations happen inside your browser using JavaScript. No numbers, cash flows, or discount rates are ever sent to any server. ### Conversions & Units #### Unit Converter URL: https://geratools.com/unit-converter Free unit converter covering length, weight/mass, temperature, volume, area and speed. Type in either direction for live two-way conversion. Runs entirely in your browser — nothing is uploaded. How to use: 1. Select a category: Choose from Length, Weight/Mass, Temperature, Volume, Area, or Speed using the category dropdown. 2. Pick your units: Select the "From" and "To" units from the dropdowns. Hit the ⇄ swap button to reverse the direction instantly. 3. Type your value: Enter a number in either field — conversion updates live in both directions as you type. FAQ: Q: Which unit categories are supported? A: Length (mm to nautical miles), Weight/Mass (mg to US short ton), Temperature (Celsius, Fahrenheit, Kelvin), Volume (ml to UK gallons), Area (mm² to square miles), and Speed (m/s to Mach). Each category covers both metric and imperial units. Q: Can I convert in both directions? A: Yes — both input fields are live. Type the source value in either box and the other updates immediately. Use the ⇄ swap button to flip from/to units without retyping. Q: How many centimetres are in an inch? A: Exactly 2.54 cm. The converter uses the exact definition (1 inch = 0.0254 m), so 12 inches (1 foot) is 30.48 cm and 1 metre is about 39.37 inches. Q: How do I convert Celsius to Fahrenheit? A: Multiply by 9/5 and add 32: °F = °C × 9/5 + 32. So 20°C = 68°F and 100°C = 212°F. To go the other way, subtract 32 then multiply by 5/9. The converter routes both through Celsius as the base unit. Q: What's the difference between a US gallon and a UK gallon? A: A UK (imperial) gallon is about 4.546 litres while a US gallon is about 3.785 litres — roughly 20% larger. The volume category includes both, plus US and UK pints, so you can convert without mixing the two systems. Q: How are the conversions calculated? A: Each category has a canonical base unit (metres, kilograms, Celsius, litres, square metres, or metres per second). Your value is converted to the base unit and then out to the target unit, using exact constants where they exist. Results show up to 8 significant figures with trailing zeros stripped. Q: Is any data sent to a server? A: No. All conversions are calculated locally in your browser using precise formula constants — no network requests are made. #### Absorbance ↔ Transmittance / % Transmittance Converter URL: https://geratools.com/absorbance-transmittance-converter Apply A = −log₁₀(T) to interconvert absorbance, transmittance (0–1), and percent transmittance from any spectrophotometer reading. Edit any one field and the others update instantly, with edge-case handling for zero and saturated readings. For analytical and clinical chemists. How to use: 1. Enter any one value: Type a value into the absorbance, transmittance, or percent transmittance field — whichever your instrument reports. 2. Read the conversions: The other two quantities update instantly using A = −log₁₀(T), so one reading gives you all three forms. 3. Check the edge cases: The tool flags physically out-of-range entries, such as transmittance above 100% or negative absorbance, and handles zero correctly. FAQ: Q: What is the relationship between absorbance and transmittance? A: Absorbance is the negative base-10 logarithm of transmittance: A = −log₁₀(T), where T is the fraction of light passing through the sample. Equivalently T = 10^(−A). Percent transmittance is simply T × 100. Q: How do I convert percent transmittance to absorbance? A: Divide %T by 100 to get T as a fraction, then take A = −log₁₀(T). For example 50 %T is T = 0.5, so A = −log₁₀(0.5) ≈ 0.301. A reading of 10 %T gives A = 1.0. Q: Why can't transmittance be zero? A: A transmittance of exactly zero would mean infinite absorbance, which the logarithm cannot represent. In practice readings approach but never reach zero. The converter treats 0 %T as effectively infinite absorbance and flags it. Q: What absorbance range is reliable? A: Most spectrophotometers are accurate roughly between A = 0.1 and A = 1.0, corresponding to about 80 %T down to 10 %T. Outside this band, small transmittance errors translate into large absorbance errors, so dilute concentrated samples to bring readings into range. Q: Is absorbance the same as optical density? A: For a clear absorbing solution, optical density (OD) and absorbance are used interchangeably and follow the same A = −log₁₀(T) relationship. The term OD is more common for turbid samples like bacterial cultures, where scattering also contributes. #### Adjusted Body Weight Calculator URL: https://geratools.com/adjusted-body-weight Calculate adjusted body weight as IBW plus 0.4 times the difference between actual weight and IBW, the standard dosing weight for obese patients. Used by pharmacists for aminoglycosides, heparin, and low-molecular-weight heparin. Runs in your browser. How to use: 1. Enter height and actual weight: Type the patient's height in centimetres and their measured actual body weight in kilograms. 2. Select sex: Choose male or female so the tool can compute the Devine ideal body weight that the adjustment builds on. 3. Read the dosing weight: The tool shows the adjusted body weight, the underlying ideal weight, and how far the patient sits above ideal, with a note on which weight to dose by. FAQ: Q: What is adjusted body weight? A: Adjusted body weight is a dosing weight for obese patients that sits between ideal and actual weight. It is calculated as ideal body weight plus 0.4 times the gap between actual and ideal weight, recognising that some drug distributes into excess adipose tissue but not all of it. Q: Why use 0.4 as the correction factor? A: The 0.4 factor reflects that hydrophilic drugs partition partially into fat. About 40 percent of the excess weight over ideal contributes to the drug's volume of distribution. Some references use slightly different factors for specific drugs, but 0.4 is the common default. Q: When should adjusted body weight be used? A: It is generally applied when actual weight is more than about 20 to 30 percent above ideal weight. Typical uses include aminoglycosides, unfractionated heparin, and low-molecular-weight heparin. For patients near or below ideal weight the adjustment is not needed. Q: What happens if actual weight is below ideal? A: Then there is no excess weight to adjust for, so the adjustment is not applied and ideal body weight (or actual weight, if even lower) is used. This tool detects that case and reports that ideal weight should be the dosing basis. Q: Which ideal-weight formula does this use? A: It uses the Devine formula to compute ideal body weight: 50 kg for men or 45.5 kg for women, plus 2.3 kg per inch of height over 60 inches. The adjusted weight is then layered on top of that figure. #### Subject Distance & Angle of View Calculator URL: https://geratools.com/angle-of-view-distance Compute the camera-to-subject distance required to fill a chosen percentage of the frame with a subject of known size, for any focal length and sensor format. Also returns the horizontal, vertical and diagonal angle of view. How to use: 1. Set focal length and sensor: Enter your lens focal length in millimetres and choose your sensor format, or enter the sensor width and height directly. 2. Describe the subject: Enter the subject height in centimetres and how much of the frame height you want it to fill, from a tight head shot to a wide full-body framing. 3. Read the distance: The tool returns the camera-to-subject distance plus the angle of view and the total field of view captured at that distance. FAQ: Q: How is the subject distance calculated? A: Using the thin-lens magnification relation. The required field-of-view height is the subject height divided by the fraction of the frame it should fill. Distance equals focal length times field height divided by sensor height. Longer lenses need more distance for the same framing. Q: What is the angle of view? A: It is the angular extent of the scene the lens captures, measured at the sensor. It is computed as two times the arctangent of half the sensor dimension divided by the focal length. The diagonal angle is what manufacturers usually quote. Q: Why does sensor size matter? A: A smaller sensor crops into the image circle, so the same focal length captures a narrower angle of view and frames the subject more tightly. That is why a 50mm lens behaves like a short telephoto on APS-C but as a standard lens on full frame. Q: What frame fill percentage should I use for portraits? A: A head-and-shoulders portrait fills roughly 60 to 80 percent of the frame height. A full-length portrait fills around 90 percent leaving headroom and floor. A tight beauty crop can exceed 100 percent of the visible head. Adjust the slider to match your composition. Q: Does this account for focus breathing or close-focus magnification? A: It uses the ideal thin-lens model, which is accurate for normal shooting distances. At extreme close range, real lenses deviate because the effective focal length and the principal-plane position shift. For macro work, use a dedicated magnification calculator. #### Arc Flash Incident Energy & Boundary Calculator URL: https://geratools.com/arc-flash-boundary-calculator Screen arc-flash incident energy in cal/cm² and the arc-flash boundary from bolted fault current, system voltage, working distance, and clearing time using the conservative Ralph Lee model, then map the result to NFPA 70E PPE categories. How to use: 1. Enter the fault parameters: Type the system line-to-line voltage in kV and the available bolted fault current in kA at the equipment. 2. Add clearing time and distance: Enter the upstream overcurrent device clearing time in seconds and the working distance in millimetres. 3. Read energy, boundary, and PPE: The tool returns the incident energy in cal/cm², the arc-flash boundary distance, and the matching NFPA 70E PPE category. FAQ: Q: Which arc-flash model does this use? A: It uses the Ralph Lee theoretical maximum-power method published in the IEEE 1584 annex. Lee assumes the worst-case condition where the arc voltage is half the system voltage, which makes it conservative — it tends to over-predict energy at low voltage. Q: Why not the full IEEE 1584-2018 equations? A: The 2018 empirical equations require equipment-specific coefficients, electrode configuration, enclosure size, and a multi-region interpolation that depend on tabulated lab data. The Lee method is the closed-form screening model and is appropriate for a first pass; a stamped study uses the full equations. Q: What working distance should I use? A: Use the standard working distance for the equipment class: about 455 mm (18 in) for low-voltage panels and 600 V switchgear, and larger for medium-voltage gear. The working distance is to the worker's torso and face, not to the arc source. Q: How is the clearing time found? A: Read it from the upstream protective device's time-current curve at the calculated arcing current. Faster clearing dramatically lowers incident energy because energy is directly proportional to time. Q: Can I rely on this to pick PPE? A: No. This is a conservative screening estimate for planning and training. Final PPE selection and equipment labelling must come from a qualified engineer's IEEE 1584-2018 study and your site's electrical safety program. #### Baseball Launch Angle & Exit Velocity Guide URL: https://geratools.com/baseball-launch-angle-calculator Enter exit velocity in mph and launch angle to estimate the expected outcome of a batted ball, from ground out to home run, using Statcast-calibrated launch-angle bands and the barrel definition. How to use: 1. Enter exit velocity: Type the exit velocity in miles per hour, the speed of the ball as it leaves the bat. 2. Enter launch angle: Type the vertical launch angle in degrees, where 0 is level, positive is upward, and negative is into the ground. 3. Read the outcome: The tool classifies the batted ball, checks the Statcast barrel zone, and estimates carry distance and the likely result. FAQ: Q: What is launch angle in baseball? A: Launch angle is the vertical angle, in degrees, at which the ball leaves the bat. Zero degrees is a level line drive, positive numbers go upward into fly balls, and negative numbers are choppers driven into the ground. Q: What is a barrel and why does it matter? A: A barrel is Statcast's label for the best contact a hitter can make. It requires at least 98 mph exit velocity paired with a launch angle near 26 to 30 degrees, with the angle window widening as velocity climbs. Barrels produce batting averages above .500. Q: What launch angle produces home runs? A: Most home runs come from launch angles between about 25 and 35 degrees combined with high exit velocity. Too low and the ball is a line drive that stays in the park, too high and it becomes a fly out with little carry. Q: Why do ground balls rarely become hits? A: Ground balls, defined as anything below roughly 10 degrees, have the lowest slugging percentage of any batted-ball type. Even hard grounders are usually fielded cleanly because infielders have time and range to convert them into outs. Q: Is the carry distance exact? A: No. The distance shown is an educational estimate from a simplified physics fit. Real carry depends on spin, wind, temperature, altitude, and the ballpark, so treat the number as a guide rather than a precise measurement. #### Bed Tramming Angle Calculator URL: https://geratools.com/bed-leveling-tram Computes the angular tilt and the required knob-turn count at each corner from your mesh bed leveling probe values. Helps manually tram an FDM printer bed to within ±0.05 mm deviation for a perfect first layer. How to use: 1. Probe each corner: Run your printer's bed mesh or paper test and record the Z height reported at each of the four bed corners in millimetres. 2. Enter heights and bed dimensions: Type the four corner values plus the left-right and front-back span between the leveling knobs, and the knob thread pitch (0.5 mm for M3 screws). 3. Turn the knobs as instructed: The tool tells you how much to lower or raise each corner and the exact number of knob rotations. Re-probe and repeat until deviation is under 0.05 mm. FAQ: Q: How are the knob turns calculated? A: Each corner's height difference from the lowest corner is divided by the screw thread pitch. One full turn of an M3 knob moves the bed 0.5 mm, so a 0.1 mm correction needs 0.2 of a turn. Q: What thread pitch should I enter? A: Most printer bed knobs use M3 or M4 screws. M3 has a 0.5 mm pitch (the default here) and M4 has a 0.7 mm pitch. Check your hardware if unsure; the wrong pitch scales every turn count. Q: What does the tilt angle tell me? A: It reports how far the bed plane leans left-to-right and front-to-back in degrees. A perfectly trammed bed reads near 0° on both axes. The angle is useful for spotting a warped or sagging frame. Q: Why use the lowest corner as the datum? A: Bed knobs only raise the bed toward the nozzle, so the calculator treats the lowest measured corner as fixed and raises the others to meet it. This avoids asking you to move a corner past its travel. Q: What deviation is good enough? A: Aim for under 0.05 mm across the whole bed for reliable first layers. Auto-leveling probes can compensate for small residual tilt, but mechanical tramming first gives the mesh the best starting point. #### Beer Dissolved CO2 & Degassing Calculator URL: https://geratools.com/beer-degassing-pressure Calculate dissolved CO2 in beer (in volumes and g/L) from temperature and the head pressure of CO2, using the standard carbonation equation. Manage carbonation and degassing in closed fermenters and kegs. Runs 100% in your browser. How to use: 1. Enter the beer temperature: Type the temperature of the beer in the keg or fermenter. CO2 dissolves more readily when cold, so temperature is the dominant input. 2. Enter the CO2 head pressure: Enter the gauge pressure of CO2 above the beer in psi (or bar). This is the partial pressure that drives gas into or out of solution. 3. Read the dissolved CO2: The calculator returns the equilibrium dissolved CO2 in volumes and grams per litre. Compare it with your target carbonation for the style. FAQ: Q: What equation does this use? A: It uses the standard brewing carbonation relationship, where dissolved CO2 volumes are a function of temperature and the absolute partial pressure of CO2. CO2 solubility rises steeply as temperature falls, following Henry's Law behaviour fitted to brewing data. Q: What is a CO2 'volume'? A: One volume of CO2 means a volume of dissolved carbon dioxide equal to the volume of the beer at standard conditions. Most beers sit between 2.2 and 2.7 volumes; British ales are lower and German wheat beers and many sparkling styles are higher. Q: How do I degas beer in a closed system? A: Lower the head pressure and/or warm the beer. Both reduce the equilibrium dissolved CO2, so gas comes out of solution. The tool lets you compare dissolved CO2 at different pressures and temperatures to plan a controlled release. Q: Why does cold beer hold more CO2? A: Gas solubility increases as temperature drops, so cold beer at a given pressure dissolves more CO2 than warm beer at the same pressure. That is why you set lower regulator pressures when force-carbonating cold. Q: Is my data uploaded? A: No. The calculation runs entirely in your browser and nothing you enter leaves your device. #### Mash Enzyme Activity Temperature Guide URL: https://geratools.com/brewing-enzyme-temperature-guide See the active temperature ranges for the main mash enzymes — beta-glucanase, protease, beta-amylase, and alpha-amylase — and learn how rest temperature shifts wort fermentability and body. Enter a mash temp to see which enzymes are active. Runs in your browser. How to use: 1. Enter your mash temperature: Type the rest temperature in Celsius; the tool also shows the Fahrenheit equivalent. 2. Read the active enzymes: The table marks which enzymes are active at that temperature and how close you are to each one's peak. 3. Tune body versus dryness: Lower rests favour beta-amylase for a dry, attenuated beer; higher rests favour alpha-amylase for fuller body and sweetness. FAQ: Q: What temperature is best for a dry, attenuated beer? A: Rest low, around 62 to 64 Celsius, where beta-amylase dominates. Beta-amylase cuts fermentable maltose from the ends of starch chains, so the yeast can ferment more of the wort and finish drier. Q: What temperature gives a fuller-bodied beer? A: Rest high, around 68 to 70 Celsius, where alpha-amylase dominates. Alpha-amylase cuts chains internally and leaves more unfermentable dextrins, which keep body and a touch of sweetness in the finished beer. Q: Do I still need a protein rest with modern malt? A: Usually not. The protease and peptidase rest around 45 to 55 Celsius matters mainly for under-modified malt or high adjunct mashes. With well-modified modern base malt a single infusion rest is normally enough. Q: What is a beta-glucan rest for? A: Around 35 to 45 Celsius, beta-glucanase breaks down gummy beta-glucans found in wheat, rye, and oats. It improves lautering and run-off speed for mashes heavy in those grains. Q: Why do enzymes stop working above 72 Celsius? A: Enzymes are proteins and denature with heat. Above roughly 72 Celsius alpha-amylase quickly loses activity, which is why a mash-out at 76 to 78 Celsius is used to lock in the sugar profile and thin the mash for lautering. #### Cambridge International Grade Converter URL: https://geratools.com/cambridge-grade-converter Enter your Cambridge International AS and A Level or IGCSE grade (A*, A, B, C, D, E or U) to get the equivalent US GPA point, UCAS tariff and approximate IB Diploma Higher Level point using standard conversion tables. How to use: 1. Choose the qualification: Select whether your grade is a Cambridge International A Level, AS Level or IGCSE, since the conversions differ between them. 2. Pick your grade: Choose the grade you achieved from A* down to U. AS Level offers no A* grade, so that option is hidden for it. 3. Read the equivalents: The tool shows the US GPA point, the UCAS tariff and the approximate IB Higher Level point for that grade. FAQ: Q: What US GPA does a Cambridge A grade equal? A: On the standard 4.0 scale used by credential evaluators, both A* and A map to a 4.0 grade point. A B maps to 3.5, a C to 3.0, a D to 2.5 and an E to 2.0, with a U scoring zero. Q: How many UCAS points is a Cambridge International A Level worth? A: Cambridge International A Levels use the same UCAS tariff as UK A-Levels: A* is 56 points, A is 48, B is 40, C is 32, D is 24 and E is 16. AS Levels are worth 40 percent of those values. Q: Does IGCSE carry UCAS tariff points? A: No. UCAS tariffs apply at AS and A Level, not at IGCSE. IGCSE results still matter for university entry and for GPA estimates, but they do not add UCAS tariff points, so the tool shows them as not applicable. Q: How does a Cambridge A Level compare to an IB subject? A: As a rough guide an A Level A* compares to an IB Higher Level 7, an A to a 6, a B to a 5 and so on. This is an approximate subject-level mapping, not an official IB conversion, and should be treated as a reference only. Q: Are Cambridge International grades the same as UK A-Levels? A: Cambridge International A Levels and AS Levels are graded on the same A* to E scale as UK A-Levels and are widely treated as equivalent for university entry, which is why they share the UCAS tariff and GPA mappings used here. #### Air Freight Chargeable Weight Calculator URL: https://geratools.com/chargeable-weight-calculator Compute volumetric weight from L×W×H in centimetres divided by 6000, take the higher of gross or volumetric weight as the chargeable weight per piece, total the shipment, and apply a rate per kilogram. Built for freight forwarders and exporters. How to use: 1. Enter each piece: Add a row per piece (or group of identical pieces) with length, width, height in centimetres, gross weight in kilograms, and quantity. 2. Let the tool pick the higher weight: For each piece the tool computes volumetric weight as L×W×H÷6000 and chooses the greater of gross or volumetric as the chargeable weight. 3. Apply a rate per kilogram: Enter your air freight rate per kilogram to see the indicative line-haul charge for the whole shipment. FAQ: Q: Why divide by 6000? A: 6000 is the IATA standard volumetric divisor for air freight when dimensions are in centimetres and weight in kilograms. It corresponds to a density of 167 kg per cubic metre, the point at which volume and weight charging are equal. Q: What is chargeable weight? A: Chargeable weight is the higher of actual gross weight and volumetric (dimensional) weight. Airlines charge on whichever is greater because light, bulky cargo takes space that could otherwise carry heavier freight. Q: Should I use the divisor 5000 instead? A: Some express integrators use 5000 for international parcels, which is more aggressive (lower threshold). True airport-to-airport air cargo under IATA convention uses 6000. This tool defaults to 6000 but lets you change it. Q: How are multiple pieces handled? A: Each piece line computes its own volumetric and gross weight and the higher value is taken, then multiplied by quantity. The shipment chargeable weight is the sum across all lines, which is then usually rounded up to the next 0.5 kg by carriers. Q: Does the rate include surcharges? A: No. The rate per kilogram you enter is the line-haul rate only. Fuel and security surcharges, AWB fees, and handling are added separately by the carrier and are not part of chargeable weight. #### Cholesterol Unit Converter (mg/dL to mmol/L) URL: https://geratools.com/cholesterol-unit-converter Converts total cholesterol, LDL, HDL, and triglycerides between mg/dL and mmol/L using analyte-specific conversion factors (38.67 for cholesterol, 88.57 for triglycerides). Built for cardiologists, GPs, and patients comparing lab results internationally. Runs 100% in your browser. How to use: 1. Choose the analyte: Select cholesterol (total, LDL, or HDL) or triglycerides, since each uses a different conversion factor. 2. Pick the direction and value: Choose whether you are converting mg/dL to mmol/L or back, then enter your lab value. 3. Read the result: The equivalent value appears instantly, rounded to two decimal places as lipid reports require. FAQ: Q: Why do cholesterol and triglycerides use different factors? A: Conversion between mass and molar units depends on molar mass. Cholesterol (and LDL/HDL, which are measured as cholesterol) divides by 38.67, while triglycerides, which are larger molecules, divide by 88.57. Q: What is the conversion factor for total cholesterol? A: To convert total cholesterol, LDL, or HDL from mg/dL to mmol/L, divide by 38.67. To go from mmol/L to mg/dL, multiply by 38.67. For example, 200 mg/dL equals about 5.17 mmol/L. Q: What is a healthy total cholesterol level? A: A desirable total cholesterol is below 200 mg/dL (5.2 mmol/L). LDL below 100 mg/dL (2.6 mmol/L) and HDL above 40 mg/dL (1.0 mmol/L) for men or 50 mg/dL (1.3 mmol/L) for women are common targets, though individual goals vary by risk. Q: Can I use this for LDL and HDL too? A: Yes. LDL and HDL are reported as cholesterol mass, so they use the same 38.67 factor as total cholesterol. Only triglycerides use the separate 88.57 factor. Q: Is my data stored anywhere? A: No. The conversion runs entirely in your browser and the values you enter are never transmitted to or saved on any server. #### Climbing Weekly Volume Calculator URL: https://geratools.com/climbing-training-volume-calculator Quantify climbing training load: log each session's duration, RPE, and number of routes or boulder problems to compute weekly training volume in Arbitrary Units, plus monotony and strain for safer periodisation. How to use: 1. Log each session: For every climbing session this week, enter how many minutes you trained, your overall session RPE from one to ten, and how many routes or problems you climbed. 2. Add all sessions: Use Add session to include every climb of the week so the weekly total reflects your real workload. 3. Read your load: The tool sums session loads into weekly volume in Arbitrary Units and reports monotony and strain to flag overly repetitive weeks. FAQ: Q: What is an Arbitrary Unit (AU)? A: An Arbitrary Unit is the product of session RPE and session duration in minutes, a method called session-RPE load. It has no physical meaning on its own but lets you compare and track total training load week to week on a consistent scale. Q: How is session load calculated? A: Each session's load equals its RPE (one to ten) multiplied by its duration in minutes. A 60-minute session at RPE 6 is 360 AU. Weekly volume is simply the sum of every session's load across the week. Q: What do monotony and strain tell me? A: Monotony is your average daily load divided by its standard deviation; high values mean every session is similar, which raises injury risk. Strain is weekly load multiplied by monotony and captures the combined effect of volume and sameness. Q: What monotony value is too high? A: Foster's original research flagged monotony above roughly 2.0 as associated with higher illness and overtraining risk. If you see a high value, introduce easier and harder sessions so your load is less uniform across the week. Q: Should I count rest days? A: This calculator sums only the sessions you log, so rest days naturally lower your weekly total and increase variation. Tracking volume across a full mesocycle helps you progress load gradually rather than spiking it. Q: What is the acute:chronic workload ratio? A: ACWR divides this week's load by your average weekly load over roughly the last four weeks. Values near 1.0 mean you are training at your established level; the commonly cited safe band is about 0.8 to 1.3, with injury risk rising sharply above roughly 1.5 — the classic post-break or climbing-trip spike. Q: How fast should weekly climbing volume increase? A: The guideline most coaches use is on the order of 5–10% per week, with a lighter consolidation week about every fourth week. Finger tendons adapt more slowly than muscles, so climbers err toward the bottom of that range when volume includes intensive fingerboard or limit bouldering. #### Cycling Speed vs Power Calculator URL: https://geratools.com/cycling-speed-power-calculator Free cycling speed vs power calculator. Enter rider weight, bike weight, gradient, and target speed to estimate the watts required, with a breakdown of rolling resistance, gravity, and aerodynamic drag. Runs in your browser. How to use: 1. Enter rider and bike weight: Type your body weight and your bike's weight in kilograms. 2. Set gradient and target speed: Enter the road gradient as a percentage and the speed you want to hold in km/h. 3. Read the power required: Total watts and a breakdown of rolling, gravity, and drag forces appear instantly. FAQ: Q: How is the required power calculated? A: The tool sums three resistances: rolling resistance, gravity on a slope, and aerodynamic drag. Each force is multiplied by your speed to get watts, then divided by drivetrain efficiency. Aerodynamic drag rises with the cube of speed, which is why high speeds need so much power. Q: Why does aerodynamic drag dominate at speed? A: Drag force grows with the square of speed and power with the cube, so doubling your speed on the flat needs roughly eight times the power. On flat fast rides, position and clothing matter far more than weight. Q: What assumptions does it use? A: It assumes a rolling resistance coefficient of 0.005 (good road tyres), a drag area CdA of 0.32 m² (hoods position), sea-level air density of 1.225 kg/m³, and 97% drivetrain efficiency. Real wind, surface, and position will shift the result. Q: Why does climbing need so much power even at low speed? A: On a slope, gravity adds a force proportional to your total weight and the gradient. At low climbing speeds drag is tiny, so power is dominated by lifting your mass — which is why weight matters most uphill. Q: Can I use it for headwind or tailwind? A: Not directly. The model assumes still air. A headwind effectively raises your air speed, increasing drag, while a tailwind reduces it. For windy estimates, adjust your target speed to approximate the air speed you experience. Q: Does altitude change the power required? A: Yes, noticeably. Air density falls with altitude — from 1.225 kg/m³ at sea level to roughly 1.0 kg/m³ near 2,000 m — shrinking the aerodynamic term. The same 40 km/h flat effort needs about 50 fewer watts at 2,000 m, which is why hour-record attempts favour high-altitude velodromes. #### Cycling Tyre Pressure Calculator URL: https://geratools.com/cycling-tyre-pressure-calculator Enter total system weight, tyre width, and surface type to compute optimal front and rear tyre pressures for road, gravel, or mountain biking, with a proper front/rear weight split. How to use: 1. Enter your system weight: Add rider, clothing, and bike weight together in kilograms — total system weight, not just body weight, drives correct pressure. 2. Set tyre width and surface: Type the tyre width in millimetres and pick road, gravel, or mountain to apply the right pressure model. 3. Read front and rear targets: The tool returns separate front and rear pressures in psi and bar, because the rear carries more weight and needs higher pressure. FAQ: Q: Why use total system weight, not just my body weight? A: The tyres carry everything: you, your kit, and the bike. A light rider on a heavy touring bike loads the tyres far more than body weight alone suggests, so pressure must be set from the combined total to avoid pinch flats. Q: Why is the rear pressure higher than the front? A: Seated riders carry roughly 60 percent of their weight on the rear wheel and 40 percent on the front. Because the rear tyre supports more load, it needs proportionally higher pressure to deflect the same amount and resist pinch flats. Q: Does wider tyre mean lower pressure? A: Yes. A wider tyre holds more air volume, so it supports the same load at lower pressure. Modern wide road and gravel tyres run far softer than narrow tyres of the past while rolling faster and gripping better on rough surfaces. Q: How does surface type change the recommendation? A: Smooth tarmac tolerates higher pressure for low rolling resistance, while gravel and mountain biking need lower pressure for grip, comfort, and to absorb impacts. The tool scales the base pressure down for rougher surfaces. Q: Should I adjust for tubeless versus tubes? A: Tubeless setups can safely run a few psi lower than the same tyre with an inner tube because there is no tube to pinch. If you run tubeless, consider taking 3 to 5 psi off the suggested figure and testing for comfort and grip. #### Gregorian ↔ Julian Calendar Converter URL: https://geratools.com/date-to-julian-calendar Convert any date between the modern Gregorian calendar and the old-style Julian calendar via the Julian Day Number. Shows the converted date, the weekday, the day-count gap between the two systems, and the underlying JDN. Runs in your browser. How to use: 1. Choose the direction: Select whether you are converting a Gregorian date to Julian or a Julian date to Gregorian. 2. Enter the date: Type the year, month and day. Years before common era can be entered as negative numbers in the proleptic sense. 3. Read the converted date: The tool returns the date in the other calendar, the weekday, the day gap between the systems, and the Julian Day Number. FAQ: Q: Why do the two calendars differ by a number of days? A: The Julian calendar adds a leap day every 4 years, slightly overestimating the solar year. The Gregonian reform skips 3 leap days every 400 years to correct this drift. Over centuries the accumulated difference grows — about 10 days in 1582, 13 days from 1900 to 2099. Q: What is a Julian Day Number? A: The Julian Day Number is a continuous count of days since a fixed epoch (noon on 1 January 4713 BC, proleptic Julian). Both calendar dates are converted to this single integer, which makes converting between calendars and computing weekdays straightforward and unambiguous. Q: What does proleptic mean here? A: A proleptic calendar is applied to dates before it was historically adopted. This converter uses the proleptic Julian and proleptic Gregorian systems, so it gives mathematically consistent results even for dates before 1582, where no single official conversion existed. Q: How does it handle the 1582 reform gap? A: It does not skip the historical 10-day jump that some countries applied in October 1582, because different countries reformed in different years. Instead it treats each calendar as continuous and reports the pure day difference, which is what you need for arithmetic. Q: Can I find the weekday of a historical event? A: Yes. The weekday is derived from the Julian Day Number, so it is correct regardless of calendar. Enter the date as recorded — Julian for most pre-1700 European records — and read the weekday from the result. #### Decoction Volume Calculator URL: https://geratools.com/decoction-mash-calc Calculate the decoction volume to pull, boil, and return so your mash steps up to a target rest temperature. Uses the standard temperature-ratio formula for traditional German lager, Pilsner, and Hefeweizen brewing. Runs entirely in your browser. How to use: 1. Enter your total mash volume: Type the combined volume of grain and water in the mash tun. This is the basis for the fraction of mash you will pull as the decoction. 2. Set the current and target rest temperatures: Enter the temperature your mash is resting at now and the higher rest you want to step up to, plus the decoction boil temperature, usually 100 degrees Celsius. 3. Read the decoction volume: The calculator shows how much thick mash to pull, boil, and stir back in to reach the target rest, along with the fraction of the mash that represents. FAQ: Q: What is a decoction mash? A: A decoction mash raises the mash temperature by pulling out a portion of the mash, boiling it, and stirring it back in. The boiling portion adds heat to lift the whole mash to the next rest. It is the traditional way to step-mash without direct heat and adds malty depth and colour. Q: How is the decoction volume calculated? A: The volume to pull equals the total mash multiplied by the temperature rise divided by the gap from the current rest up to boiling. In symbols, decoction equals total mash times (target minus start) over (boil minus start). The boiling portion carries the extra heat needed to reach the target rest. Q: Should I pull a thick or thin decoction? A: Pull a thick decoction, meaning more grain than liquid. Keeping most of the liquid and its enzymes in the main mash protects conversion, while the grain-heavy pull provides the malty flavour and colour from boiling. Thick decoctions are standard for step-up rests in traditional schedules. Q: What temperatures do the classic rests use? A: Common rests include a protein or ferulic acid rest near 45 to 52 degrees Celsius, a beta-amylase rest around 62 to 65 degrees, an alpha-amylase rest near 70 to 72 degrees, and a mash-out around 76 to 78 degrees. A triple-decoction schedule steps through several of these by boiling successive pulls. Q: Why does the returned decoction need to be boiling? A: The formula assumes the pulled portion is at boiling, since that is the maximum heat it can carry back. If you return it cooler, it adds less heat and the mash falls short of the target rest. Boil the decoction fully, then stir it back in gradually while watching the main mash temperature climb. #### DELF/DALF Score to CEFR Converter URL: https://geratools.com/delf-dalf-score-converter Enter your DELF A1/A2/B1/B2 or DALF C1/C2 score (out of 100) to see your CEFR level, passing threshold (50/100, minimum 5/25 per component), and common university requirements. Runs in your browser. How to use: 1. Choose your exam level: Select the DELF or DALF level you sat, from A1 up to C2, since each level maps to a fixed CEFR band. 2. Enter your four component scores: Type your marks for listening, reading, writing, and speaking, each out of 25. 3. Read your result: The tool totals your four scores out of 100 and checks both the 50-point overall pass mark and the 5-point minimum on every component. FAQ: Q: What is the DELF/DALF pass mark? A: Every DELF and DALF level is scored out of 100, split into four components of 25 marks each. You pass with a total of at least 50 out of 100, but you must also score at least 5 out of 25 on each of the four components. Falling below 5 on any one component fails the whole exam regardless of your total. Q: How do DELF and DALF levels map to CEFR? A: The mapping is direct and official. DELF covers the lower four levels: A1, A2, B1, and B2. DALF covers the top two: C1 and C2. Passing a given diploma certifies that exact CEFR level, which is why French universities and immigration offices accept the diploma name as proof of level. Q: Why is there a per-component minimum? A: The 5-out-of-25 floor stops a candidate from passing while being completely unable to perform one of the four skills. Someone with perfect reading but no speaking ability would still fail, because the diploma is meant to certify balanced communicative competence at the level. Q: Which DELF or DALF level do universities require? A: Most French-taught degree programmes ask for DELF B2 as a minimum, and many selective or postgraduate programmes prefer DALF C1. Always check the specific institution, since some accept B1 for certain courses and others require C1 across the board. Q: Is the diploma valid forever? A: Yes. Unlike many language tests, the DELF and DALF diplomas have lifetime validity and never expire. Once you pass a level the certification stands permanently, although individual institutions may still ask for a recent result for their own policy reasons. #### Dovetail Angle & Layout Calculator URL: https://geratools.com/dovetail-angle-calculator Turn a dovetail slope ratio such as 1:6 for softwood or 1:8 for hardwood into a precise bevel angle in degrees, then lay out evenly spaced tails and pins across any board width and thickness. Includes a scaled SVG layout diagram for direct marking. How to use: 1. Choose a slope ratio: Enter the dovetail ratio as 1 to N, using a lower N such as 6 for softwoods and a higher N such as 8 for hardwoods. 2. Enter board dimensions: Type the board thickness and width, the number of tails you want, and the half-pin width you prefer at the two edges. 3. Read the angle and layout: The tool returns the bevel angle, the baseline tail and pin widths, and draws a scaled diagram you can copy for marking out. FAQ: Q: What dovetail ratio should I use? A: A 1 to 6 slope, about 9.5 degrees, suits softwoods like pine because the steeper angle resists pull-apart in the weaker fibres. A 1 to 8 slope, about 7.1 degrees, looks more refined and works well in hardwoods. Many makers simply pick the look they like, since both hold strongly when cut accurately. Q: How is the dovetail angle calculated? A: The slope ratio 1 to N is rise over run, so the angle from the vertical is the arctangent of one divided by N. A 1 to 6 ratio gives arctan of one sixth, which is about 9.46 degrees, and a 1 to 8 ratio gives about 7.13 degrees. Q: Does the angle change with board thickness? A: No, the angle is fixed by the ratio alone. Thickness only affects how far the angled line travels across the face, which the tool reports as the side offset. A thicker board simply means a longer sloped cut at the same angle. Q: How many tails should I use? A: There is no fixed rule. Narrow drawer sides often use two or three tails, while wide carcass boards may use five or more. As a guide, keep pins narrower than tails for a traditional look, and make sure the half-pins at the edges are stout enough to resist splitting. Q: Can I use this for both through and half-blind dovetails? A: Yes for the angle and the face layout, since both joints use the same slope and tail spacing on the show face. Half-blind joints differ only in how deep you cut the sockets, which is set by the receiving board thickness rather than by this layout. #### Drill Point Angle Calculator URL: https://geratools.com/drill-point-angle-calculator Calculate the cone depth of a twist-drill point for standard 118 degree, split-point 135 degree, and other point angles at any diameter, plus the half-angle and the depth-stop setting needed for full-diameter breakthrough on a through hole. Built for machinists. How to use: 1. Enter drill diameter: Type the drill diameter in inches; this sets the radius the point geometry is built from. 2. Choose the point angle: Select the included point angle, such as 118 degrees for general purpose or 135 degrees for a split point. 3. Read cone depth and stop: The tool returns the cone depth and half-angle, and adds your material thickness to give the depth-stop setting for a clean through hole. FAQ: Q: What is cone depth? A: Cone depth is the axial length of the conical tip of the drill — how much farther the very point reaches past where the full-diameter cutting edges begin. It matters whenever a hole must reach full diameter at a given depth. Q: What is the formula? A: Cone depth equals the drill radius divided by the tangent of half the point angle. For a 118 degree drill the half-angle is 59 degrees, giving a cone depth of about 0.3 times the diameter. Q: Why does a 135 degree drill have a shorter point? A: A larger included angle makes a flatter, shorter cone. At 135 degrees the half-angle is 67.5 degrees, so the tangent is larger and the cone depth shrinks to roughly 0.2 times the diameter compared with 0.3 for a 118 degree drill. Q: How do I set a depth stop for a through hole? A: Add the cone depth to the material thickness. The full diameter does not break through until the cylindrical cutting edges clear the back face, so the drill must travel the thickness plus the length of its own point. Q: Does this work for countersinks? A: The same trigonometry applies to any conical point, so a 90 or 60 degree countersink cone depth can be read off too. For sizing a countersink to a fastener head, though, use the head diameter rather than the tool diameter. #### Enzyme Unit Activity Calculator URL: https://geratools.com/enzyme-unit-activity-calculator Computes enzyme activity in international units per mL and per mg from the change in absorbance, molar extinction coefficient, path length, reaction volume, and time using the Beer-Lambert kinetic relationship. For enzymology and diagnostic biochemistry labs. How to use: 1. Enter the absorbance change and time: Type the change in absorbance read during the linear phase of your assay and the time interval over which you measured it. 2. Add the assay constants: Enter the molar extinction coefficient of your product, the cuvette path length, and the total reaction volume. 3. Read activity in U/mL and U/mg: Provide the enzyme volume, any dilution factor, and the protein concentration to get volume and specific activity instantly. FAQ: Q: What exactly is one enzyme unit? A: One international unit, or IU, is the amount of enzyme that converts one micromole of substrate per minute under defined assay conditions. All the numbers this tool reports are anchored to that definition, so activity scales directly with the reaction rate. Q: How does absorbance turn into a reaction rate? A: The Beer-Lambert law links absorbance to concentration through the extinction coefficient and path length. Dividing the absorbance change by time gives the rate of concentration change, and multiplying by the reaction volume gives micromoles of product made per minute. Q: What is the difference between U/mL and U/mg? A: Volume activity in U per mL describes how active a given volume of your enzyme prep is. Specific activity in U per mg divides that by protein concentration, giving activity per unit protein, which is the standard measure of enzyme purity and is what you track during purification. Q: Why must I measure during the linear phase? A: The micromole-per-minute definition assumes a constant rate. Early in a reaction, before substrate depletion or product inhibition set in, the absorbance rises linearly. Reading the slope during that window gives an accurate initial velocity and a valid unit value. Q: What extinction coefficient should I use? A: Use the coefficient of the species you are actually measuring at your assay wavelength, not the substrate. A classic example is NADH at 340 nm, with an extinction coefficient of 6220 per molar per centimetre, used in many dehydrogenase assays. #### Fish Weight Estimator by Length & Species URL: https://geratools.com/fish-weight-from-length Select a species (bass, walleye, trout, pike, crappie, catfish and more) and enter length, with optional girth, to estimate live weight using published length-weight regression formulas. Built for anglers practicing catch-and-release. How to use: 1. Pick the species: Choose your fish from the list. Each species uses its own length-weight regression constants, so the estimate matches that fish's body shape. 2. Enter the length: Type the total length in inches. If you measured girth too, enter it for a more accurate shape-based estimate. 3. Read the estimated weight: The tool returns the estimated weight in pounds and ounces using the standard W = a × L raised to b formula, or the girth formula when girth is supplied. FAQ: Q: How accurate are length-to-weight estimates? A: Length-weight formulas are statistical averages for a species and are typically within 10 to 15 percent of true weight for a fish of average condition. A heavy, well-fed fish weighs more than the estimate; a lean one weighs less. Adding girth improves accuracy. Q: What is the W = a × L to the b formula? A: It is the standard length-weight regression used in fisheries science. Length is raised to a power b (usually near 3, since weight scales with volume) and multiplied by a species constant a. Each species has its own a and b fitted from sampled fish. Q: When should I use the girth formula instead? A: If you measured girth, the girth-based formula (length times girth squared, divided by a constant) captures the individual fish's body thickness, which the length-only formula cannot. Use girth for trophy fish or unusually fat or thin specimens. Q: Should I measure total length or fork length? A: These formulas assume total length, measured from the tip of the snout to the end of the tail with the tail squeezed. Fork length (to the fork of the tail) is shorter and will under-estimate weight, so use total length where possible. Q: Does this work for catch-and-release records? A: Yes. Estimating weight from a quick length and girth measurement lets you release a fish unharmed instead of putting it on a scale in a net. Many catch-and-release tournaments and personal-best logs accept formula-based weights. #### Focal Length Equivalence Table URL: https://geratools.com/focal-length-equivalence Free focal length equivalence calculator. Enter a focal length on any sensor format and see the matching native focal lengths and fields of view across full-frame, APS-C, Micro Four Thirds, medium format, and 1-inch. Perfect for photographers switching camera systems. How to use: 1. Enter your focal length: Type the focal length printed on your lens, in millimetres. 2. Choose the sensor format: Select the format the lens is mounted on, such as full-frame, APS-C, or Micro Four Thirds. 3. Read the comparison table: The tool shows the full-frame equivalent and the native focal length that gives the same framing on every other format. FAQ: Q: How is full-frame equivalent focal length calculated? A: Multiply the native focal length by the format's crop factor. A 35 mm lens on a 1.5× APS-C body has a full-frame equivalent of 35 × 1.5 = 52.5 mm, meaning it frames the scene like a 52.5 mm lens would on full-frame. The crop factor is the ratio of sensor diagonals. Q: Does a crop sensor change the actual focal length of a lens? A: No. A 50 mm lens is always 50 mm regardless of the body it is mounted on. The smaller sensor simply records a tighter crop of the projected image, which narrows the field of view, so the equivalent focal length describes framing, not the lens's physical optics. Q: What crop factors do common formats use? A: Full-frame is 1.0×, Nikon, Sony, and Fuji APS-C are about 1.5×, Canon APS-C is roughly 1.6×, Micro Four Thirds is 2.0×, the 1-inch type is about 2.7×, and the popular 44×33 medium format is about 0.79×. This tool uses these standard values to build the comparison. Q: Why does field of view matter more than focal length? A: Field of view is what you actually see in the frame, and it depends on both focal length and sensor size. Comparing the angle of view lets you match framing across systems precisely, which is why the table shows the horizontal angle for each format alongside the focal length. Q: Does equivalence affect depth of field and exposure too? A: Equivalent focal length matches framing but not everything. A smaller sensor at the same equivalent framing and aperture gives more depth of field and gathers less total light, so an f/2.8 on Micro Four Thirds behaves like roughly f/5.6 full-frame for background blur, even though exposure brightness is unchanged. #### Gregorian ↔ Hebrew Date Converter URL: https://geratools.com/hebrew-date-converter Convert any Gregorian date to the Hebrew lunisolar calendar and back, with correct month names including Adar I and Adar II in leap years. Uses the standard molad-based arithmetic with all four postponement rules. Runs in your browser. How to use: 1. Choose the direction: Select Gregorian to Hebrew to convert a civil date, or Hebrew to Gregorian to convert a Jewish calendar date. 2. Enter the date: Type the three date parts. Hebrew months are numbered with Tishrei as month 7, Nisan as month 1, and Adar II as month 13 in leap years. 3. Read the converted date: The tool returns the equivalent date in the other calendar, naming the Hebrew month correctly including Adar I and Adar II. FAQ: Q: Why does Tishrei have month number 7 instead of 1? A: The Hebrew year for counting purposes begins in Tishrei (around September), but the months are traditionally numbered from Nisan in spring, which the Torah calls the first month. So Nisan is month 1 and Tishrei is month 7, even though the year number increments at Tishrei. Q: How does the converter handle leap years? A: Hebrew leap years, which occur 7 times in a 19-year cycle, add a thirteenth month. In those years the month otherwise called Adar splits into Adar I (month 12) and Adar II (month 13). The tool detects leap years automatically and labels the months accordingly. Q: What are the postponement rules? A: The date of Rosh Hashana can be pushed back by one or two days to prevent certain holidays falling on awkward weekdays. The converter applies all the standard dechiyot rules through the molad calculation, so Rosh Hashana always lands on the canonically correct day. Q: Why do Hebrew years have different lengths? A: A common year can be 353, 354 or 355 days and a leap year 383, 384 or 385 days. The variation comes from whether Cheshvan and Kislev have 29 or 30 days, which is determined so the calendar stays aligned with both moon and sun and obeys the postponement rules. Q: Is the day counted from sunset? A: In Jewish practice the day begins at sunset the previous evening. This converter maps whole civil dates to whole Hebrew dates, so for an event after nightfall you may want the next Hebrew date. The conversion itself is calendar-accurate for the daytime portion of the date. #### Hop AAU (Alpha Acid Units) Calculator URL: https://geratools.com/hop-aau-calculator Multiply hop weight in ounces by alpha acid percentage to compute Alpha Acid Units (AAU), also called Homebrew Bitterness Units (HBU). Quickly scale recipes and substitute hops without a full IBU calculation. Runs 100% in your browser. How to use: 1. Enter the hop weight: Type the weight of the hop addition in ounces. A typical bittering charge for a 5-gallon batch is 1–2 oz. 2. Enter the alpha acid percentage: Read the alpha acid (AA%) figure printed on the hop package. Cascade is often around 5.5%, while a high-alpha hop like Magnum can exceed 14%. 3. Read the AAU total: The calculator multiplies weight by AA% to give the AAU (HBU). Add several additions together for a recipe total, then substitute hops while keeping AAU constant. FAQ: Q: What is the formula for AAU? A: AAU = hop weight in ounces × alpha acid percentage (as a whole number). For example, 1.5 oz of a 6% alpha hop gives 1.5 × 6 = 9 AAU. AAU and HBU are the same figure under two different names. Q: What is the difference between AAU and HBU? A: There is none. Alpha Acid Units (AAU) and Homebrew Bitterness Units (HBU) are identical — both equal weight in ounces multiplied by alpha acid percentage. HBU is just the older homebrewer name for the same number. Q: How do I substitute one hop for another using AAU? A: Keep the AAU constant. If a recipe calls for 2 oz of a 5% hop (10 AAU) and you only have a 10% hop, use 1 oz to keep the same 10 AAU and roughly the same bitterness. Q: Does AAU account for boil time or utilization? A: No. AAU is a quick approximation of bitterness potential only. It ignores boil time, gravity, and hop utilization. For accurate International Bitterness Units, use a Tinseth or Rager IBU calculator. Q: Is my recipe data stored anywhere? A: No. The calculation runs entirely in your browser. Nothing you enter is uploaded or saved on any server. #### IBAN Length by Country URL: https://geratools.com/iban-length-by-country Reference the exact IBAN character length and structure for every IBAN-participating country, then validate any IBAN's length and MOD-97 check digits in your browser. Includes the BBAN format pattern per country. How to use: 1. Choose a country: Select a country to see its official IBAN length and the BBAN format pattern after the country code and check digits. 2. Paste an IBAN: Type or paste any IBAN; the tool reads the first two letters as the country code and looks up the expected length. 3. Read the result: The tool confirms whether the length matches the country standard and runs the MOD-97 check digit test to flag typos. FAQ: Q: Why does IBAN length differ between countries? A: Each country sets its own BBAN (Basic Bank Account Number) format, which varies by how many digits it needs for bank, branch, and account number. Germany uses 22 characters, Norway 15, and Malta 31. The country code and 2 check digits are always the first 4. Q: What are the first four characters of an IBAN? A: The first two letters are the ISO 3166 country code, and the next two digits are the MOD-97 check digits. The rest is the country-specific BBAN. So DE89 means Germany with check digits 89, followed by the German account details. Q: How does the MOD-97 check work? A: Move the first four characters to the end, convert letters to numbers (A=10 ... Z=35), and compute the big number modulo 97. A valid IBAN gives a remainder of 1. Any other remainder means a transcription error. Q: Does the right length guarantee a valid IBAN? A: No. Correct length is necessary but not sufficient. The MOD-97 check digits catch most single-character typos and digit swaps. This tool checks both length and check digits, but only the bank can confirm the account exists. Q: Should I store IBANs with spaces? A: Store them without spaces in a single uppercase string. Spaces in groups of four are a display convention for humans. Always strip whitespace before validating or saving to a database. #### ISA Temperature & Deviation Calculator URL: https://geratools.com/isa-temperature-calculator Calculate the International Standard Atmosphere temperature at any pressure altitude using the 1.98 degrees Celsius per 1,000 ft lapse rate to the tropopause, and find the ISA deviation between the standard value and the actual outside air temperature. How to use: 1. Enter the pressure altitude: Type the pressure altitude in feet at which you want the standard temperature. 2. Optionally add the actual OAT: Enter the outside air temperature in Celsius to also calculate the ISA deviation; leave it blank to skip. 3. Read the standard temperature and deviation: The tool shows the ISA standard temperature in Celsius and Fahrenheit, and the ISA deviation such as ISA plus 10. FAQ: Q: What is the ISA standard temperature formula? A: Below the tropopause, ISA temperature is 15 degrees Celsius minus 1.98 degrees per 1,000 ft of pressure altitude. At 10,000 ft that is 15 minus 19.8, or about minus 4.8 degrees Celsius. Above the standard tropopause it stays constant at minus 56.5 degrees. Q: What is ISA deviation? A: ISA deviation is the actual outside air temperature minus the ISA standard temperature at the same altitude, written as ISA plus or minus a number. ISA plus 15 means the air is 15 degrees warmer than standard, which thins the air and reduces engine and wing performance. Q: Where is the tropopause in the ISA model? A: The standard tropopause sits at 36,089 ft, where the temperature reaches minus 56.5 degrees Celsius. Above that, up to about 65,000 ft, the standard atmosphere is isothermal, so the temperature stops falling and holds at minus 56.5 degrees. Q: Why does ISA deviation matter for performance? A: Air density depends on temperature, and most performance charts are built around standard conditions. A positive ISA deviation means warmer, thinner air: longer takeoff and landing rolls, reduced climb, and a higher true airspeed for a given indicated airspeed. Charts correct for it using the deviation. Q: Is this pressure altitude or true altitude? A: The ISA model is defined against pressure altitude, the altitude shown when the altimeter is set to 1013.25 hPa or 29.92 inHg. Use pressure altitude for the most consistent results, especially when feeding the answer into performance and true-airspeed calculations. #### Container VGM (Verified Gross Mass) Calculator URL: https://geratools.com/iso-container-weight-vgm-calculator Sums cargo, packaging, dunnage, and container tare to produce the Verified Gross Mass required under SOLAS VI Reg 2 for export booking submissions, and warns if the total exceeds the container's maximum gross mass. For shippers and freight forwarders. How to use: 1. Pick the container type: Select your ISO container type to load its standard tare weight, or enter the exact tare stamped on the CSC plate. 2. Enter cargo and securing weights: Type the cargo weight, plus the weight of packaging, securing materials, and any dunnage or blocking inside the box. 3. Read and declare the VGM: The tool sums everything into the Verified Gross Mass and warns if it exceeds the container's maximum gross mass before you submit the booking. FAQ: Q: What is VGM and why is it required? A: Verified Gross Mass is the total weight of a packed container including its tare. Since 2016 the SOLAS Chapter VI Regulation 2 has required the shipper to declare a VGM before a container can be loaded onto a vessel, to prevent dangerous mis-stowage from inaccurate weights. Q: What is the difference between Method 1 and Method 2? A: Method 1 weighs the entire packed container on a calibrated scale. Method 2 adds the certified weights of the cargo, packaging, dunnage, and the container tare. This tool implements Method 2; Method 1 simply requires a single verified scale reading. Q: Where do I find the container tare weight? A: The tare is stamped on the container's CSC safety approval plate and usually painted on the doors. Use that figure rather than the generic default, because real tares vary by manufacturer and container condition. The tool lets you override the standard tare. Q: What happens if the VGM exceeds the maximum gross mass? A: You cannot legally ship an overweight container. The maximum gross mass, also on the CSC plate, is the structural limit. If the calculator flags an overweight, you must remove cargo or split the load across more containers before booking. Q: Does dunnage and packaging really need to be counted? A: Yes. SOLAS requires the VGM to include everything inside the container, so pallets, bracing, lashing, desiccant, and packaging all count. Omitting them understates the declared mass and can make the booking non-compliant. #### MIDI Note Number Converter URL: https://geratools.com/midi-note-number Free MIDI note number converter. Translate between MIDI numbers (0-127), note names with octave (C-1 to G9) and frequency in Hz, with adjustable A4 reference tuning. Essential for MIDI programming, DAWs and synths. Runs in your browser. How to use: 1. Choose a conversion direction: Select whether you are converting from a MIDI note number or from a note name such as C#4. 2. Enter your value: Type a MIDI number from 0 to 127, or a note name with octave like A4 or Db3. 3. Read the full mapping: The tool shows the matching MIDI number, note name with octave, and frequency in Hz for your chosen A4 reference. FAQ: Q: How does a MIDI note number map to a note? A: MIDI defines 128 notes numbered 0 to 127. Number 0 is C-1 and each step up is one semitone. Middle C is MIDI 60 (C4) and A4 is MIDI 69. The note name is the number modulo 12, and the octave is floor(number / 12) minus 1. Q: How is the frequency calculated from a MIDI number? A: The tool uses frequency = A4 · 2^((midi − 69) / 12). With A4 at 440 Hz, MIDI 69 gives 440 Hz, MIDI 60 (middle C) gives about 261.63 Hz, and each octave doubles the frequency. Changing the A4 reference scales every note proportionally. Q: Why does middle C show as C4 here but C3 elsewhere? A: There are competing octave-numbering conventions. This tool uses scientific pitch notation, where middle C (MIDI 60) is C4. Some manufacturers, notably older Yamaha gear, label the same note C3. The MIDI number is unambiguous, so use that when in doubt. Q: Can I enter flats as well as sharps? A: Yes. The note-name input accepts both, so Db3 and C#3 both resolve to the same MIDI number. Output note names are shown using sharps by convention, but the conversion is identical either way since they are enharmonic equivalents. Q: What is the valid range? A: MIDI numbers run from 0 (C-1, about 8.18 Hz) to 127 (G9, about 12 543 Hz at A4 = 440). Values outside 0 to 127, or note names whose octave pushes them out of that range, are rejected because they are not representable in standard MIDI. #### Miniature Scale Converter URL: https://geratools.com/miniature-scale-converter Enter a real-world measurement and pick a target scale (1:1 to 1:700) to get the scaled size in mm and inches. For miniature painters, terrain builders, model railroaders, and wargamers. How to use: 1. Enter the real-world size: Type the full-size dimension of the object you want to model, in millimetres or inches. 2. Pick a target scale: Choose a named scale (HO, N, 1/72, 28mm heroic) or type a custom ratio denominator. 3. Read the scaled size: The tool divides the real size by the scale ratio and shows the model size in both mm and inches. FAQ: Q: How is a scale ratio applied? A: A scale of 1:N means the model is N times smaller than the real object. The tool divides your real-world dimension by N. So a 1800 mm door at 1:87 (HO) becomes about 20.7 mm tall. Q: What scale is 28mm heroic wargaming? A: 28mm refers to the figure height (foot to eye) of a human miniature, which corresponds to roughly 1:56 to 1:60. This tool uses 1:56 as the working ratio for 28mm heroic, the common Warhammer-style standard. Q: What are HO and N scale? A: HO scale is 1:87 and N scale is 1:160, both standard model-railroad scales. HO is the most popular worldwide. N is roughly half the linear size of HO, useful for fitting more track in a small space. Q: Can I work backwards from a model size? A: Yes. Switch the direction toggle to scale-up and the tool multiplies your model dimension by the ratio to give the equivalent real-world size, useful for figuring out what a miniature represents. Q: Does the scale affect volume and weight? A: Linear dimensions divide by N, but volume and mass scale by N cubed. A 1:56 figure has roughly 1/175000 the volume of the real object, which is why resin miniatures use so little material. #### Mortar Mix & Volume Calculator URL: https://geratools.com/mortar-calculator From wall dimensions and joint size, calculates the mortar volume a brick or block job needs and converts it into bags of pre-mixed mortar or separate bags of Portland cement and mason's sand at a Type S, N, or M ratio, with a 10% waste factor. How to use: 1. Enter the wall and unit: Type the wall area and choose whether you are laying brick or block. The unit size and mortar joint set how much mortar each square foot consumes. 2. Pick the mortar type: Select Type S, N, or M. Each type fixes the cement-to-sand ratio, which determines how the total volume splits into cement and sand. 3. Read bags and components: The tool shows the mortar volume plus bags of pre-mixed mortar, or separate Portland and sand bags, including a 10 percent waste allowance. FAQ: Q: How much mortar does a brick wall need? A: A rough rule is about 7 cubic feet of mortar per 100 square feet of single-wythe brick wall with standard 3/8 inch joints, or roughly one 80 lb bag of pre-mixed mortar for every 30 to 35 bricks. Block walls use less mortar per square foot than brick. Q: What is the difference between Type S, N, and M mortar? A: They differ in cement-to-lime-to-sand ratio and strength. Type N is general above-grade work, Type S is stronger for below-grade and structural masonry, and Type M is the strongest for foundations and retaining walls. Higher strength uses more cement per unit of sand. Q: How many bags of cement and sand do I need? A: After finding the total mortar volume, the tool splits it by the selected type's cement-to-sand ratio. It then divides cement volume by the yield of a 94 lb Portland bag and sand volume by a typical bag or cubic-foot figure to give bag counts. Q: Why add a 10 percent waste factor? A: Mortar is lost to droppings, board waste, tooling, and partial batches that stiffen before use. A 10 percent allowance is standard so you do not run short mid-course, which would force a cold joint or a second mixing session. Q: Should I buy pre-mixed or mix my own? A: Pre-mixed bagged mortar is simplest and most consistent for small jobs. Mixing Portland cement, lime, and sand on site is cheaper at volume and lets you tune the type, but it requires accurate proportioning and is only worth it on larger work. #### Opioid MME Converter (Morphine Milligram Equivalents) URL: https://geratools.com/opioid-mme-converter Convert oxycodone, hydrocodone, fentanyl, buprenorphine, methadone, and other opioids to total daily morphine milligram equivalents using CDC conversion factors, with 50 and 90 MME risk flags. Runs in your browser. How to use: 1. Choose the opioid: Select each opioid the patient is taking from the list, which includes oral agents, methadone bands, and transdermal patches. 2. Enter dose and frequency: Type the dose per administration in mg (or mcg/hr for patches) and how many times per day it is taken. 3. Read total daily MME: Add a row for every opioid on the regimen. The tool sums all rows into a total daily MME and flags the 50 and 90 MME thresholds. FAQ: Q: What is an MME? A: A morphine milligram equivalent expresses any opioid dose in terms of the equivalent amount of oral morphine, using fixed conversion factors. It lets clinicians compare and total doses across different opioids to gauge overall opioid burden and overdose risk. Q: Which conversion factors does this use? A: The published CDC factors: morphine 1, hydrocodone 1, oxycodone 1.5, hydromorphone 5, oxymorphone 3, codeine 0.15, tramadol 0.1, tapentadol 0.4, plus banded methadone factors and 2.4 per mcg/hr for fentanyl patches. Q: Why are 50 and 90 MME flagged? A: CDC guidance advises increased caution and monitoring at or above 50 MME per day and careful justification and overdose-risk review at or above 90 MME per day. The tool highlights when a regimen crosses these thresholds. Q: Why is methadone banded? A: Methadone has a non-linear, dose-dependent conversion: its factor rises from 4 to 12 as the daily dose increases. Pick the band that matches the patient's total daily methadone dose. Methadone conversions are complex and should involve a specialist. Q: Can I use MME to switch opioids directly? A: No. MME is for assessing total daily burden and overdose risk, not for calculating an exact rotation dose. Incomplete cross-tolerance means a direct MME swap can overdose a patient, so opioid rotation needs clinical dose reduction and expertise. #### PCR Annealing Temperature Optimizer URL: https://geratools.com/pcr-annealing-temp-estimator Takes the melting temperatures of forward and reverse PCR primers, or their sequences, and suggests an optimal annealing temperature using the lower-Tm-minus-5 rule plus a gradient range, to reduce mispriming. For molecular biologists optimising new PCR assays. How to use: 1. Enter the primer melting temperatures: Type the Tm of the forward and reverse primers in degrees Celsius, usually taken from your oligo synthesis report. 2. Or paste the primer sequences: Optionally paste the primer sequences and the tool estimates each Tm directly, overriding the typed values. 3. Read the suggested temperature: The tool subtracts 5 degrees from the lower primer Tm and proposes a gradient range to test on the thermocycler. FAQ: Q: How is the annealing temperature chosen? A: The classic rule takes the lower of the two primer melting temperatures and subtracts about 5 degrees Celsius. Annealing a little below the weaker primer's Tm gives stable binding for both primers while staying specific enough to avoid mispriming. Q: Why use the lower of the two Tm values? A: The primer with the lower melting temperature is the limiting one. If the annealing temperature is set near the higher Tm, the weaker primer may not bind reliably, reducing yield. Anchoring on the lower Tm keeps both primers working. Q: How does the tool estimate Tm from a sequence? A: For short primers under 14 bases it uses the Wallace rule, two degrees per A or T and four per G or C. For longer primers it uses the basic GC formula, 64.9 plus 41 times the GC content adjustment divided by length. These are quick estimates, not salt-corrected nearest-neighbour values. Q: Why test a gradient? A: Real templates and buffers behave differently from the simple rule. Running a gradient of roughly plus or minus 3 degrees around the suggested temperature lets you pick empirically the temperature that gives the cleanest specific band with the least non-specific product. Q: Do the two primer Tm values need to match? A: Ideally they should be within about 5 degrees of each other. A large mismatch makes it hard to find one annealing temperature that suits both primers, so it is worth redesigning a primer if the gap is wide. The tool flags the difference for you. #### Pipe Flow Velocity & Pressure Drop Calculator URL: https://geratools.com/pipe-velocity-calculator Computes water velocity in ft/s and Hazen-Williams friction loss in psi per 100 ft from flow rate, nominal pipe size, and material C-value. Helps plumbers and mechanical engineers keep supply velocity inside the recommended 4 to 8 ft/s range and check pressure drop on a run. How to use: 1. Enter the flow rate: Type the design flow rate through the pipe in gallons per minute (GPM). 2. Pick the pipe size and material: Select the nominal pipe size and the material, which sets the inside diameter and the Hazen-Williams C roughness coefficient. 3. Read velocity and pressure drop: The tool returns velocity in ft/s and friction loss in psi per 100 ft, and flags whether velocity sits inside the recommended 4 to 8 ft/s range. FAQ: Q: What velocity range should water supply pipe stay in? A: Most plumbing guides keep cold and hot water supply velocity between 4 and 8 ft/s. Below 4 ft/s pipes can be oversized and sluggish, and above 8 ft/s you risk erosion-corrosion, water hammer, and noise. Hot recirculation lines are often kept under 4 ft/s to limit copper erosion. Q: What is the Hazen-Williams C-value? A: C is an empirical roughness coefficient: higher means smoother. Smooth plastics like PVC and CPVC are around 150, new copper near 140, and older steel drops toward 100 to 120 as it scales. A lower C produces more friction loss for the same flow. Q: How accurate is the Hazen-Williams equation? A: It is a reliable empirical fit for water near room temperature in the turbulent flow range typical of plumbing, which is why most plumbing codes use it. It loses accuracy for very hot or very cold water, very small pipes, or non-water fluids, where the Darcy-Weisbach method is preferred. Q: Why does pressure drop matter for sizing? A: Total friction loss along a run, plus elevation and fitting losses, must stay within the pressure available from the supply minus the fixture demand. Sizing each segment so velocity and psi-per-100-ft stay reasonable keeps the worst fixture above its minimum flow pressure. Q: Does this include fitting losses? A: No. The result is straight-pipe friction loss only. Add equivalent length for elbows, tees, and valves, plus 0.433 psi per foot of elevation rise, to get the true total pressure drop on a real run. #### Plato / Brix / Specific Gravity Converter URL: https://geratools.com/plato-brix-sg-converter Bidirectional converter between degrees Plato, Brix, and specific gravity for brewing and winemaking. Uses the ASBC polynomial formula for accurate gravity-to-Plato conversion and shows working. Runs 100% in your browser. How to use: 1. Pick the scale you have: Choose whether you are entering a reading in degrees Plato, Brix, or specific gravity. The other two scales are calculated automatically. 2. Enter your reading: Type the value from your hydrometer or refractometer. For specific gravity use the full form such as 1.048, not just 48. 3. Read the converted values: The tool shows all three scales plus the working it used, so you can cross-check against a recipe or brewing reference. FAQ: Q: How do you convert specific gravity to degrees Plato? A: This tool uses the ASBC cubic polynomial: Plato = -616.868 + 1111.14 x SG - 630.272 x SG^2 + 135.997 x SG^3. It is accurate across the normal brewing range and is the standard formula used by professional brewers. Q: Are Brix and Plato the same thing? A: They are very close but defined against slightly different reference substances. Brix is based on sucrose and Plato on a maltose-equivalent sugar, so they diverge by less than 0.1 degrees in the brewing range. Many brewers treat them as interchangeable, and this tool does too unless you need lab precision. Q: Why is my refractometer reading off after fermentation? A: Refractometers read Brix accurately only in wort with no alcohol. Once fermentation starts, alcohol skews the refractive index, so a finished-beer Brix reading needs a separate alcohol-correction formula and will not match a hydrometer here. Q: What specific gravity does 12 degrees Plato equal? A: Roughly 1.048. A common rule of thumb is that each degree Plato is about 4 gravity points, so 12 Plato is near 1.048 and 20 Plato is near 1.083. The polynomial gives the exact figure. Q: Does this work for wine and cider too? A: Yes. Winemakers and cider makers often measure in Brix, and the same gravity relationship applies. Enter your Brix or SG reading and the tool converts it just as it does for beer wort. #### Weld Preheat & Interpass Temperature Calculator URL: https://geratools.com/preheat-interpass-temp-calculator Compute carbon equivalent (CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15) from steel chemistry and estimate the minimum preheat temperature using the AWS D1.1 hardness-control approach, plus typical maximum interpass limits by material group. How to use: 1. Enter steel chemistry: Type the percentage of each alloying element from the steel's mill certificate; leave any unknown element at zero. 2. Set thickness and category: Enter the plate thickness and choose the hydrogen level of your electrode, which drives the preheat band. 3. Read preheat and interpass: The tool shows the IIW carbon equivalent, a recommended minimum preheat, and a typical maximum interpass temperature for the material group. FAQ: Q: What is carbon equivalent and why does it matter? A: Carbon equivalent (CE) rolls a steel's alloy content into a single number representing hardenability. Higher CE means a greater tendency to form hard, crack-prone martensite in the heat-affected zone, which is why higher-CE steels need more preheat. Q: Which carbon equivalent formula does this use? A: It uses the IIW formula adopted by AWS and EN 1011: CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15. All inputs are weight percentages taken from the mill certificate. Q: How is the preheat temperature determined? A: Preheat rises with carbon equivalent, thickness, and diffusible hydrogen. This tool maps CE bands to recommended minimum preheat consistent with the AWS D1.1 hardness-control method; for code work always confirm against the governing table and procedure. Q: What is interpass temperature? A: Interpass temperature is the metal temperature just before the next weld pass is deposited. Too low risks cracking; too high degrades toughness, especially in quenched-and-tempered steels, so a maximum is specified by group. Q: Can I trust this for code-critical welds? A: Use it for planning and estimating. For ASME or AWS D1.1 production work the welding procedure specification (WPS) and the governing code table are the authority. Preheat from a qualified WPS always takes precedence. #### Pressure Altitude Calculator URL: https://geratools.com/pressure-altitude-calculator Calculate pressure altitude from indicated altitude and altimeter setting using the standard 1,000 feet per inch of mercury correction from 29.92. Built for student and instrument-rated pilots doing performance and oxygen calculations. How to use: 1. Enter indicated altitude: Type the altitude shown on your altimeter, in feet, with your current altimeter setting dialled in. 2. Enter the altimeter setting: Enter the current altimeter setting from ATIS or ATC, choosing inches of mercury or hectopascals to match your instrument. 3. Read pressure altitude: The tool applies the standard correction from 29.92 inHg and shows pressure altitude in feet, the value used for performance and oxygen rules. FAQ: Q: What is pressure altitude? A: Pressure altitude is the altitude indicated when the altimeter is set to the standard datum of 29.92 inHg, or 1013.25 hPa. It is the height in the standard atmosphere corresponding to the ambient pressure, and is the basis for flight levels and most performance charts. Q: What is the correction formula? A: Pressure altitude equals indicated altitude plus 1,000 feet for every inch of mercury the altimeter setting is below 29.92, and minus 1,000 feet for every inch above. In hectopascals the factor is about 27 feet per hPa from 1013.25. Q: Why not just set 29.92 on the altimeter? A: You can, and at and above the transition altitude pilots do exactly that to read pressure altitude directly as a flight level. This calculator lets you compute it on the ground from the local setting without re-baroing the altimeter. Q: When do I need pressure altitude? A: Performance charts for takeoff, climb, and cruise are indexed by pressure altitude, and it feeds the density altitude calculation. Oxygen and cabin-altitude rules are also defined in terms of pressure altitude rather than indicated altitude. Q: Does temperature affect pressure altitude? A: No. Pressure altitude depends only on pressure and the altimeter setting. Temperature does affect true altitude and density altitude, but the pressure-altitude conversion itself is purely a pressure correction from the standard datum. #### Print Speed vs Quality Tradeoff Calculator URL: https://geratools.com/print-speed-quality-tradeoff Estimate when a 3D print's quality degrades as speed rises. Compares your target speed against the material's volumetric melt limit and the printer's input-shaping ringing threshold to flag under-extrusion and ghosting risk. How to use: 1. Select your material: Pick PLA, PETG, ABS/ASA, TPU or Nylon. Each carries a typical maximum volumetric flow rate (the rate the hotend can melt filament). 2. Enter slicer geometry and target speed: Type your layer height, line width and the speed you want to run. These set how much plastic per second the speed demands. 3. Read the verdict: The tool compares demanded flow to the melt ceiling and your input-shaping ringing threshold, then tells you the safe top speed for clean surfaces. FAQ: Q: What is volumetric flow rate and why does it limit speed? A: Volumetric flow rate is how many cubic millimetres of plastic the hotend melts per second, calculated as layer height times line width times speed. Every hotend has a ceiling; once your speed demands more flow than that, the nozzle can't keep up and you get under-extrusion. Q: Why does input shaping let me print faster? A: Ringing (ghosting) is mechanical vibration from rapid direction changes, not a flow problem. Input shaping cancels the printer's resonant frequencies so corners stay crisp at high acceleration, raising the speed at which ghosting appears from roughly 80 mm/s to several hundred. Q: Does a higher nozzle temperature raise the melt limit? A: Yes. A hotter nozzle melts filament faster, so a higher temperature (within the material's safe range) increases the maximum volumetric flow and therefore the maximum clean speed. Volcano-style and high-flow hotends raise it further. Q: Why is the safe speed lower than the melt-limit speed? A: Right at the melt ceiling, flow is unstable and surfaces glaze or develop gaps. The tool uses a derated 'quality' fraction of the ceiling so walls stay smooth, which is why the clean-surface speed is well below the absolute maximum. Q: Are these flow numbers exact for my printer? A: No — they are typical values for a standard 0.4 mm brass nozzle. Run a flow-rate calibration test (extrude at rising speeds and watch for under-extrusion) to find your exact hotend ceiling, then treat this tool as a starting estimate. #### RC Helicopter Blade Pitch & Head Speed Calculator URL: https://geratools.com/rc-helicopter-blade-pitch-calculator Enter rotor diameter, motor KV, battery voltage, and target head speed to compute the gear ratio and pinion needed, blade tip speed and Mach, plus recommended collective pitch range for hover and 3D flight. How to use: 1. Enter motor and battery: Type your motor KV rating and your battery voltage. The product is the unloaded motor RPM that the gearing reduces down to head speed. 2. Set rotor and target head speed: Enter the main rotor diameter in millimetres and the head speed you want in RPM, then pick a flight style for the pitch range. 3. Read gearing and pitch: The tool shows the required gear ratio, a suggested pinion for your main gear, the blade tip speed and Mach number, and the collective pitch range for hover and aerobatics. FAQ: Q: How is the required gear ratio calculated? A: Motor RPM equals KV times battery voltage. The gear ratio needed to reach your target head speed is that motor RPM divided by the head speed. For example, a 450 KV motor on 44.4 volts spins about 19,980 RPM, so a 2,200 RPM head needs roughly a 9:1 reduction. Q: Why is real head speed lower than the calculation? A: KV times voltage is the unloaded motor speed. Under the aerodynamic load of the rotor, the motor turns at roughly 80 to 90 percent of that figure, so a governor will hold a slightly lower head speed than the pure geometric ratio suggests. Size the gearing a touch high and let the governor trim it. Q: What collective pitch range should I run? A: Scale and sport flying typically uses about minus 2 to plus 10 degrees, sport 3D runs symmetric minus 10 to plus 10, and hardcore 3D often goes to minus 12 to plus 12. Hover sits around 4 to 6 degrees of positive collective on most electric collective-pitch helis. Q: Why does blade tip speed matter? A: Tip speed equals pi times rotor diameter times head speed divided by 60. As tips approach the speed of sound, drag rises sharply, the rotor gets loud, and blades are stressed. Keeping tip Mach below about 0.65 avoids transonic losses, which is why larger rotors run lower head speeds. Q: How do I pick the right pinion? A: Divide your main gear tooth count by the required gear ratio to get the ideal pinion. Round to the nearest available pinion, then check the resulting head speed the tool reports. Swapping a tooth or two on the pinion is the usual way to fine-tune head speed. #### RC Servo Torque & Horn Length Calculator URL: https://geratools.com/rc-servo-torque-calculator Enter control surface chord, span, airspeed and deflection to estimate the aerodynamic hinge moment, then apply your control horn and servo arm lengths to get the required servo torque in oz-in and kg-cm with a safety margin. For RC aircraft builders sizing servos. How to use: 1. Measure the control surface: Enter the chord (depth of the moving surface) and the span (length) in centimetres, along with the plane's expected airspeed and the maximum deflection angle. 2. Enter your linkage geometry: Add the control horn length and servo arm length in millimetres so the tool applies the leverage ratio between the surface and the servo. 3. Pick a servo above the result: Select a servo rated at or above the margined torque shown in kg-cm or oz-in to guarantee it holds the surface at speed. FAQ: Q: How is servo torque for a control surface estimated? A: The tool uses the standard RC empirical hinge-moment relation T = 8.5e-6 × C × L² × V² × sin(D), where C is the surface chord, L is its span, V is airspeed and D is deflection. That gives the moment at the hinge, which is then scaled by the control horn to servo arm leverage ratio. Q: Why does airspeed matter so much? A: Aerodynamic load rises with the square of airspeed, so doubling speed roughly quadruples the hinge moment. A servo that is fine for a slow trainer can be badly undersized on a fast sport jet, which is why high-speed models need much stronger servos. Q: How does control horn length change the torque? A: The required servo torque scales by the ratio of control horn length to servo arm length. A longer horn relative to the servo arm lowers the torque the servo must produce, but it also reduces the throw of the surface, so there is a trade-off between effort and travel. Q: What safety margin should I use? A: We apply a 1.5x margin over the calculated value to cover gusts, snap loads and binding. For aerobatic, 3D or high-speed aircraft you should pick an even larger margin, since brief peak loads can far exceed the steady-state estimate. Q: Is this accurate enough to choose a servo? A: It is a sound sizing estimate, not a wind-tunnel result. Use it to land in the right torque class and then round up to a real servo. When in doubt between two servos, choose the stronger one — a stalled servo can cause loss of control. #### Ship ETA / Speed / Time Calculator URL: https://geratools.com/ship-eta-speed-time-calculator Solve the distance-speed-time triangle in nautical miles and knots: find voyage time at a given speed, the speed needed to hit a deadline, or arrival time from a departure timestamp. Marine operators and port agents use it for schedule and laycan management. How to use: 1. Choose what to solve for: Pick whether you want voyage time, the required speed, or the estimated time of arrival. 2. Enter the two known values: Supply the distance in nautical miles plus either a speed in knots or a target time, and a departure time for ETA mode. 3. Read the answer: The tool returns voyage time as days, hours, and minutes, the required speed in knots, or the arrival timestamp, depending on the mode. FAQ: Q: What is a knot? A: A knot is one nautical mile per hour. Because a nautical mile is one minute of latitude, speed in knots maps directly onto progress along a meridian. A vessel doing 14 knots covers 14 nautical miles every hour through the water. Q: How is voyage time calculated? A: Voyage time in hours equals distance in nautical miles divided by speed in knots. The tool then breaks that into days, hours, and minutes. For example 3360 nautical miles at 14 knots is 240 hours, which is exactly 10 days. Q: How do I find the speed needed to meet a deadline? A: Required speed equals distance divided by the available time in hours. If you have 3360 nautical miles to cover in 9 days, that is 216 hours, so you need 3360 divided by 216, about 15.6 knots. Check that figure against the vessel's safe maximum. Q: Does this use speed through water or over ground? A: The calculation is purely geometric, so it uses whatever speed you enter. For an accurate ETA use speed over ground, which already includes the effect of currents and leeway. Speed through the water alone will mislead the arrival time in a strong set. Q: What about pilotage, canals, and port time? A: The tool gives steaming time only. Add allowances for pilot boarding, canal transits, slow-steaming zones, and any waiting for a berth or tide. Build a margin into the ETA so you arrive within the laycan rather than exactly on the wire. #### Shipping Emissions Calculator URL: https://geratools.com/shipping-emissions-calculator Enter cargo weight, distance and transport mode — container ship, airfreight, HGV or rail — to compute freight CO2e using DEFRA tonne-km emission factors and compare modes side by side. For logistics teams, procurement and Scope 3 Category 4 transport reporting. How to use: 1. Enter cargo weight and distance: Type the shipment weight in tonnes and the distance it travels in kilometres for the leg you are assessing. 2. Pick the transport mode: Choose container ship, airfreight, HGV road, or rail. Each has a DEFRA emission factor per tonne-kilometre. 3. Read the emissions and comparison: The tool shows the CO2e for your chosen mode and a table comparing all four so you can see the cleanest option. FAQ: Q: What is a tonne-kilometre? A: A tonne-kilometre is moving one tonne of cargo one kilometre. Freight emission factors are expressed per tonne-km, so multiplying weight in tonnes by distance in km and then by the factor gives the total CO2e for the shipment. Q: Why is airfreight so much worse than sea? A: Aircraft burn enormous amounts of fuel to stay aloft, so per tonne-km they emit roughly 30 to 50 times more CO2 than a container ship. Sea freight is the lowest-carbon long-distance mode by a wide margin, which is why mode choice dominates freight emissions. Q: Where do the factors come from? A: The per-tonne-km factors are DEFRA freight conversion factors: large container ships around 0.012 kg, rail around 0.027 kg, HGV around 0.11 kg, and long-haul airfreight around 0.6 kg CO2e per tonne-km. Real values vary with load factor and vessel size. Q: Does this cover well-to-wheel emissions? A: These are operational (tank-to-wheel) factors for the transport itself. A full well-to-wheel or well-to-tank assessment adds the emissions of producing and distributing the fuel, which can increase the totals by roughly 15 to 25 percent depending on mode. Q: How does this fit Scope 3 reporting? A: Upstream and downstream transport falls under Scope 3 Category 4 and Category 9 of the GHG Protocol. Activity-based tonne-km calculations like this are the recommended method when you know shipment weights and distances, giving more accuracy than spend-based estimates. #### Solana Compute Unit & Priority Fee Estimator URL: https://geratools.com/solana-compute-unit-estimator Enter the instruction types in your Solana transaction (SOL transfer, token transfer, NFT mint, swap, account creation) to estimate the compute units consumed, then pick a priority-fee tier to compute the total cost in lamports, SOL, and USD at your entered SOL price. Runs in your browser. How to use: 1. Add your instructions: Enter how many of each instruction type your transaction contains — SOL transfers, token transfers, NFT mints, swaps, or account creations. 2. Pick a priority-fee tier: Choose low, medium, or high urgency, which sets the micro-lamports-per-compute-unit price, and enter the current SOL price. 3. Read the cost: The tool sums estimated compute units, adds the base 5,000-lamport signature fee plus the priority fee, and shows the total in lamports, SOL, and USD. FAQ: Q: How are compute units estimated? A: Each instruction type has a typical compute-unit cost: a simple SOL transfer is around 300 CU, an SPL token transfer around 4,500 CU, an account creation around 3,000 CU, an NFT mint around 30,000 CU, and a DEX swap around 60,000 CU. The tool sums your instruction counts to estimate the transaction's total CU usage. Q: What is a priority fee on Solana? A: Beyond the flat 5,000-lamport-per-signature base fee, you can attach a priority fee priced in micro-lamports per compute unit. It bids for faster inclusion when the network is congested. Priority fee equals compute-unit limit times the micro-lamport price, divided by one million to convert to lamports. Q: What micro-lamport prices do the tiers use? A: The tool uses illustrative tiers of roughly 1,000 micro-lamports/CU (low), 10,000 (medium), and 50,000 (high). Real optimal pricing is dynamic — query getRecentPrioritizationFees from an RPC node at send time, because congestion changes minute to minute. Q: Why add a buffer to the compute limit? A: If a transaction exceeds the compute-unit limit it requested, it fails. Best practice is to set the limit slightly above the simulated usage. The tool prices the priority fee against the estimated CU usage; in production, set your ComputeBudget limit a little higher to avoid failures. Q: Are these costs exact? A: No. Compute-unit costs vary by program implementation and account state, and SOL's price moves constantly. Treat the output as a planning estimate. For exact figures, simulate the transaction against an RPC node, which returns the actual units consumed. #### Solar PPFD & DLI Outdoor Garden Calculator URL: https://geratools.com/solar-ppfd-dli-converter Enter average daily sun hours and an estimated PPFD to compute outdoor Daily Light Integral in mol per square metre per day, then compare it to full-sun, part-shade, and shade plant targets. For gardeners assessing planting sites. How to use: 1. Estimate your sun hours: Enter the average number of hours of direct sun your planting site receives in a day during the growing season. 2. Set the PPFD level: Enter the average photon flux for that light; full midday sun is roughly 2000 micromoles, so use a lower figure for hazy or filtered light. 3. Read the DLI and category: The tool converts to a Daily Light Integral and tells you whether the site suits full-sun, part-shade, or shade plants. FAQ: Q: What is DLI and why does it matter for plants? A: Daily Light Integral is the total amount of usable light a plant receives in a day, measured in moles of photons per square metre. It is the single best predictor of plant growth and flowering, because plants respond to total daily light, not just peak brightness. Q: How do PPFD and DLI relate? A: PPFD is the instantaneous photon flux in micromoles per square metre per second. DLI is PPFD integrated over the photoperiod. The conversion is DLI equals PPFD times seconds of light divided by one million, since a mole is a million micromoles. Q: What PPFD should I use for outdoor sun? A: Full, unobstructed midday summer sun is around 2000 micromoles per square metre per second. Bright overcast is roughly 400 to 800, and dappled shade under a tree might average 200 to 500. Because outdoor light varies through the day, the figure you enter is an effective average. Q: What DLI do different plants need? A: As a rough guide, full-sun vegetables and fruiting crops want 20 to 40 mol per day, leafy greens and many perennials are happy at 10 to 20, and true shade plants tolerate 5 to 10. Below about 5 mol most plants struggle to do more than survive. Q: Does this replace a quantum meter? A: No. A proper quantum or PAR meter logged through the day gives a real DLI. This tool estimates DLI from your sun hours and an assumed PPFD, which is ideal for quickly judging a planting site but less precise than a measured integral. #### Sheet Metal Spring-Back Angle Calculator URL: https://geratools.com/spring-back-calculator Estimates sheet metal spring-back and the required die over-bend angle from material yield strength, elastic modulus, inside bend radius, and thickness. Built-in property defaults for mild steel, stainless 304, and 6061-T6 aluminum. Runs in your browser. How to use: 1. Pick the material: Choose mild steel, stainless 304, or 6061-T6 aluminum to load yield strength and modulus, or pick Custom to enter your own. 2. Enter the geometry: Type the inside bend radius, sheet thickness, and the final included angle you want the finished part to hold. 3. Read the over-bend: The tool returns the spring-back factor, the degrees of opening, and the die angle you must over-bend to land on the target. FAQ: Q: What causes spring-back in sheet metal? A: During bending, the outer fibres stretch and inner fibres compress. Part of that strain is elastic, so when the punch releases, the elastic portion recovers and the bend opens up. Higher-strength, lower-modulus metals recover more. Q: Why does aluminum spring back more than steel? A: Spring-back scales with yield strength divided by elastic modulus. Aluminum 6061-T6 has a high yield strength but a modulus roughly one-third that of steel, so its elastic recovery is much larger for the same bend. Q: How does bend radius affect spring-back? A: A larger inside-radius-to-thickness ratio means a thicker elastic core relative to the plastic zone, so more of the deformation recovers. Tight bends near the minimum radius spring back the least. Q: Is this exact enough for production tooling? A: It is a sound first estimate from the elastic recovery equation, but friction, tooling wear, grain direction, and material lot variation all shift the result. Always confirm the over-bend on a test coupon before committing. Q: What units does the calculator use? A: Yield strength and modulus are in MPa, radius and thickness in millimetres, and all angles in degrees. The final included angle is the angle of the finished part, such as 90 degrees for a right-angle bend. #### Structural Steel Beam Weight Calculator URL: https://geratools.com/structural-steel-beam-weight Looks up listed weight in lb/ft and kg/m for standard AISC W, S, HP, C, MC, L, WT, and HSS sections from an embedded table and multiplies by piece length and quantity. Outputs individual piece weight, total order weight, and estimated freight tonnage. How to use: 1. Choose the section: Pick the shape family such as W, channel, or HSS, then select the exact section designation from the list. 2. Enter length and quantity: Type the length of each piece in feet and how many pieces are in the order. 3. Read total weight and tonnage: The tool returns per-piece weight, total order weight in pounds and kilograms, and freight tonnage in US tons and metric tonnes. FAQ: Q: Where do the weights come from? A: The weight per foot is the listed theoretical weight from the AISC Steel Construction Manual shapes database. For wide-flange shapes the second number in the name is the weight, so a W12X26 weighs 26 lb/ft. Q: Are connection plates and bolts included? A: No. The listed weight is the bare rolled section only. Add an allowance for connection plates, bolts, stiffeners, paint, and any fireproofing when estimating shipped weight and erection loads. Q: How is freight tonnage calculated? A: Total pounds are divided by 2000 for US short tons and the kilogram total is divided by 1000 for metric tonnes. Use these to plan truckloads and crane picks, remembering trucks are usually capped near 20 to 24 tons of payload. Q: Does it handle metric sections? A: It shows kg/m and kilogram totals alongside the imperial figures so you can quote in either system, but the section list itself uses imperial AISC designations common in North America. Q: How accurate is the result? A: Listed mill weights are accurate to within rolling tolerance, typically a couple of percent. For exact certified weights, request a mill test report for the specific heat of steel you receive. #### Token Unlock Selling Pressure Estimator URL: https://geratools.com/token-unlock-pressure-estimator Enter an upcoming token unlock amount, current token price, daily trading volume, and the typical sell-through rate to compute the unlock's USD value, its unlock-to-volume ratio, and an estimated short-term price impact from dilutive vesting events. How to use: 1. Enter the unlock and price: Input how many tokens unlock in the event and the current token price to get the gross USD value entering circulation. 2. Add volume and sell-through: Enter the average daily trading volume in USD and the share of unlocked tokens you expect to be sold rather than held. 3. Read the pressure metrics: The tool shows unlock value, the unlock-to-volume ratio, expected sell volume, and an order-of-magnitude price-impact estimate. FAQ: Q: What is a token unlock? A: A token unlock is the scheduled release of previously locked tokens — typically allocations to the team, investors, or treasury — into circulating supply per a vesting schedule. Large unlocks increase circulating supply and can create selling pressure if recipients sell. Q: How is the price impact estimated? A: The tool uses a simplified square-root market-impact model: impact ≈ k × √(sellValue ÷ dailyVolume), scaled to a percentage. Real impact depends on order-book depth, liquidity, and market sentiment, so treat the figure as an order-of-magnitude indicator, not a prediction. Q: What is the unlock-to-volume ratio? A: It is the USD value of the unlock divided by average daily trading volume. A ratio above 1 means the unlock exceeds a full day of volume — a strong signal of potential pressure. Below 0.1 the market can usually absorb it easily. Q: What sell-through rate should I use? A: Sell-through is the share of unlocked tokens that actually get sold. Investor and team unlocks often see 20–60% sold near the event; community or staking unlocks are usually lower. If unsure, model a range. Q: Is my input data sent anywhere? A: No. All calculations run locally in your browser. The figures you enter are never transmitted or stored. #### Vessel Deadweight Utilisation Calculator URL: https://geratools.com/vessel-deadweight-utilisation-calculator Subtracts vessel constants (ballast, stores, FO, FW, crew) from total deadweight at a given displacement to yield maximum cargo intake and DWT utilisation percentage. Ship operators and chartering managers use this to determine cargo-carrying capacity and voyage profitability. How to use: 1. Enter the deadweight at draft: Type the vessel's total deadweight (DWT) at the relevant load line or sailing draft from the hydrostatic tables. 2. List the deductibles: Enter fuel oil, diesel oil, fresh water, ballast retained, and the constant (stores, crew, effects, unpumpable liquids). 3. Read cargo intake and utilisation: The tool subtracts all deductibles from deadweight to give the maximum cargo intake and the percentage of deadweight used by cargo. FAQ: Q: What is deadweight (DWT)? A: Deadweight is the total weight a vessel can carry at a given draft: cargo plus fuel, fresh water, ballast, stores, crew, and constant. It is the difference between loaded displacement and lightship weight, read from the hydrostatic tables at the sailing draft. Q: What is the vessel constant? A: The constant is the difference between the calculated lightship weight and the actual measured displacement when empty. It captures stores, spares, crew effects, mud, rust, and unpumpable liquids, and is typically 100 to 400 tonnes. It must be deducted from deadweight before cargo can be loaded. Q: How is maximum cargo intake calculated? A: Cargo intake equals deadweight at the sailing draft minus all deductibles: fuel oil, diesel oil, fresh water, ballast retained, and the constant. Whatever deadweight remains after these is available for cargo. Q: What is a good deadweight utilisation? A: DWT utilisation is cargo intake divided by total deadweight. On a full cargo with minimal bunkers a bulk carrier can exceed 90 percent. Long voyages requiring large bunker quantities, or draft restrictions in port, reduce utilisation and therefore voyage revenue. Q: Why does draft limit cargo intake? A: Port and canal draft restrictions cap the displacement you can reach, which caps deadweight. If the deadweight available at the permitted draft is less than the cargo plus required bunkers, you must reduce cargo or bunkers. Always use the deadweight at the most restrictive draft on the voyage. #### Vessel Speed-Fuel Optimisation Calculator URL: https://geratools.com/vessel-speed-fuel-optimisation-calculator Evaluates total voyage cost (bunker cost plus time-charter hire times voyage days) across a range of speeds using the cube-law consumption model to identify the cost-minimising speed for a given hire rate and bunker price. For charterers and ship operators. How to use: 1. Enter the voyage and vessel data: Type the voyage distance in nautical miles, the vessel's reference speed and its daily fuel consumption at that speed. 2. Add prices and a speed range: Enter the bunker price per tonne, the daily time-charter hire, and the minimum and maximum speeds you want to evaluate. 3. Read the optimal speed: The tool sweeps speeds in half-knot steps, splitting fuel and hire cost, and highlights the speed with the lowest total voyage cost. FAQ: Q: Why does fuel consumption scale with the cube of speed? A: The power a hull needs to overcome wave-making and frictional resistance rises roughly with the cube of speed at displacement velocities. Since fuel burn tracks engine power, daily consumption follows the same cube relationship near the design speed. Q: Why is the slowest speed not always cheapest? A: Slowing down cuts fuel sharply but lengthens the voyage, so you pay more days of charter hire. The optimum balances falling fuel cost against rising hire cost, which is why a mid-range speed usually wins. Q: What is slow steaming? A: Slow steaming means deliberately running below design speed to save fuel when bunker prices are high or hire is cheap. This calculator quantifies the trade-off so you can decide whether it actually lowers total cost on a given voyage. Q: How accurate is the cube-law model? A: It is a good approximation within a few knots of the reference speed where the consumption curve is smooth. Far from that point, or in heavy weather and with hull fouling, real curves diverge, so treat the result as a planning estimate. Q: Does the tool send my voyage data anywhere? A: No. Every calculation runs entirely in your browser. Nothing about your vessel, route, or commercial terms is transmitted or stored on a server. #### Water Pressure Reducing Valve (PRV) Setting Calculator URL: https://geratools.com/water-pressure-reducer-setting-calculator Adjusts a pressure-reducing valve set-point for the elevation difference to the highest fixture at 0.433 psi per foot, then checks that downstream static pressure stays under the IPC 80 psi cap and above the minimum needed for flush valves. For plumbers. How to use: 1. Enter the target fixture pressure: Type the pressure you want at the highest or most critical fixture, such as 35 psi for a typical faucet or 15 to 25 psi for a flush valve. 2. Add the elevation rise: Enter the vertical height in feet from the PRV up to that fixture so the tool can add back the static head lost climbing the building. 3. Read the PRV set-point: The tool returns the pressure to dial into the PRV and flags whether the resulting downstream static pressure violates the 80 psi code maximum. FAQ: Q: Why add pressure for elevation? A: Water loses static pressure as it rises: about 0.433 psi for every foot of height. To deliver a target pressure at an upper-floor fixture, the PRV must be set higher than the target by the head lost climbing to that fixture. Q: Where does 0.433 psi per foot come from? A: It is the weight of a one-foot column of water over one square inch. A 2.31-foot column equals 1 psi, so 1 divided by 2.31 is about 0.433 psi per foot. This is the standard plumbing conversion between vertical height and static pressure. Q: What is the 80 psi maximum? A: The International Plumbing Code section 604.8 limits static water pressure at fixtures to 80 psi to protect valves, hoses, and appliances. If the PRV set-point plus any factors pushes downstream static pressure above 80 psi, the code requires a pressure-reducing valve and a lower setting. Q: Why is there a minimum pressure too? A: Fixtures need a minimum flow pressure to work: ordinary faucets around 8 psi, but flushometer (flush) valves need roughly 15 to 25 psi to flush properly. The tool warns if the target you entered for a flush valve falls below 15 psi. Q: Does this account for friction loss in the pipe? A: No. This tool covers static elevation head only. Under flow you also lose pressure to pipe friction and fittings, which can be significant on long or undersized runs. Size pipe and add friction loss separately when setting pressure under design flow. #### Aircraft Weight & Balance Calculator URL: https://geratools.com/weight-and-balance-calculator Compute loaded weight, total moment, and centre of gravity from empty weight, fuel, passengers, and baggage at each station, then check both against your aircraft's published limits. Built for pilots and dispatchers doing preflight weight and balance. How to use: 1. Enter each loading station: For empty aircraft, fuel, each seat row, and baggage, type the weight and the arm (distance from the datum) for that station. 2. Set the limits: Enter the maximum allowable weight and the forward and aft CG limits from your aircraft's flight manual. 3. Read weight and CG: The tool sums weights and moments, divides total moment by total weight to find the CG, and flags whether weight and CG fall within limits. FAQ: Q: How is the centre of gravity calculated? A: The CG is the total moment divided by the total weight. Each station's moment is its weight multiplied by its arm. Summing all moments and all weights, then dividing, gives the single arm at which the aircraft balances. Q: What is an arm and a moment? A: The arm is the horizontal distance from the reference datum to a load, usually in inches. The moment is weight times arm, a measure of turning effect. Moments add up, which is why weight and balance works as a sum-and-divide problem. Q: What happens if the CG is out of limits? A: An out-of-limits CG makes the aircraft unsafe to fly. Too far forward and it may be hard to flare or rotate; too far aft and it can become unstable or unrecoverable in a stall. The tool flags forward, aft, and overweight conditions. Q: Can I use this for any aircraft? A: Yes, the method is universal. You supply the empty weight, empty arm, station arms, and the weight and CG limits from your specific aircraft's flight manual. The arithmetic is identical for a light single or a heavy jet. Q: Does it handle CG in percent MAC? A: This tool reports CG as an arm in the same distance unit you enter, typically inches from datum. To convert to percent of mean aerodynamic chord, you would apply your aircraft's leading-edge-of-MAC arm and MAC length separately. #### Wire Pulling Tension & Sidewall Pressure Calculator URL: https://geratools.com/wire-pulling-tension-calculator Calculate cable pulling tension through straight runs and bends using the capstan e to the mu-theta formula with bundled lubricated friction coefficients for PVC, EMT, rigid and HDPE conduit, then check sidewall bearing pressure against NEMA WC 74 limits. How to use: 1. Describe the run: Enter total cable weight per foot, the straight length before the bend, and pick the conduit type to set the friction coefficient. 2. Add the bend: Enter the bend angle, bend radius and any incoming tension carried into this section. 3. Check the limits: Read the tension after the bend and the sidewall bearing pressure, comparing both against the cable's pulling limit and the NEMA WC 74 sidewall limit. FAQ: Q: How is pulling tension through a bend calculated? A: Bends multiply tension by the capstan formula: outgoing tension equals incoming tension times e raised to the friction coefficient times the bend angle in radians. A 90 degree bend with a friction of 0.3 multiplies tension by about 1.6. Q: What is sidewall bearing pressure? A: Sidewall bearing pressure is the force the cable presses against the inside of a conduit bend, equal to the tension at the bend divided by the bend radius in feet. Excessive pressure crushes the insulation, so NEMA WC 74 sets limits, commonly around 500 lb/ft for single conductors. Q: What friction coefficients should I use? A: With cable lubricant, typical values are about 0.25 for HDPE duct, 0.30 for PVC, 0.35 for rigid steel and 0.40 for EMT. Dry pulls are far higher. The tool bundles lubricated defaults and lets you override with a measured value. Q: How do I handle multiple bends? A: Calculate one section at a time. Take the tension after one bend and enter it as the incoming tension for the next straight run and bend. Chaining sections this way builds the full tension profile of a complex pull. Q: What is the maximum allowable pulling tension? A: For copper conductors a common rule is 0.008 lb per circular mil of total conductor area, capped by the pulling-eye or basket-grip rating. Compare the calculated final tension against that limit and stop the pull or add a feed point if it is exceeded. #### Overhead Wire Sag & Tension Calculator URL: https://geratools.com/wire-weight-sag-calculator Compute midspan sag and horizontal tension for overhead distribution conductors using the parabolic sag formula D = w x L squared / 8T, with bundled ACSR, AAC, and copper weight tables and a temperature correction. For line workers and utility designers. How to use: 1. Pick the conductor: Select the conductor type and size so the tool loads the correct unit weight in pounds per foot. 2. Enter span and tension: Type the horizontal span length and the horizontal tension at your stringing temperature, then the design and service temperatures. 3. Read sag and slack: The tool returns midspan sag, temperature-adjusted tension, conductor length in the span, and the sag-to-span ratio. FAQ: Q: What formula does this sag calculator use? A: It uses the parabolic sag approximation, D = w x L squared / (8 x T), where w is conductor weight per foot, L is span length, and T is horizontal tension. This is the standard field formula and is accurate when sag stays below roughly ten percent of the span. Q: Why does sag change with temperature? A: Aluminium and copper conductors expand when heated by current and sun, so the wire lengthens and tension drops, which increases sag. The tool applies a first-order thermal correction using each metal's coefficient of expansion to estimate hot-day sag from your stringing-day tension. Q: When does the parabolic formula stop being accurate? A: The parabola assumes a uniform horizontal load and small sag. Once the sag-to-span ratio passes about ten percent, or for very long crossings, you should switch to the exact catenary equation or a change-of-state sag-tension program that accounts for ice, wind, and creep. Q: Does this replace a sag-tension program? A: No. It is a quick estimate for inspection and planning. Final stringing charts, NESC clearance checks, and ice and wind loading require a full program such as SAG10 or PLS-CADD with the manufacturer's conductor data. Q: What is the sag-to-span ratio used for? A: It is a quick sanity check on the result and on the validity of the parabolic model. Typical distribution spans run a few percent. A high ratio warns you that the wire is loose or lightly tensioned and that you should verify ground clearance carefully. #### Julian to Gregorian Date Converter URL: https://geratools.com/julian-to-gregorian-converter Free Julian to Gregorian date converter — translate historical dates between the old Julian calendar and the modern Gregorian calendar in both directions, with the Julian Day Number shown. Runs entirely in your browser, nothing is uploaded. How to use: 1. Choose a direction: Select whether you are converting a Julian date to Gregorian or a Gregorian date back to Julian. 2. Enter the date: Type the year, month and day of the date you want to convert. 3. Read the converted date: The equivalent date in the other calendar appears instantly, along with its Julian Day Number. FAQ: Q: Why do Julian and Gregorian dates differ? A: The Julian calendar over-counts leap years, drifting roughly one day every 128 years. The Gregorian reform of 1582 dropped 10 days and refined the leap-year rule, so historical Julian dates sit several days off from the modern Gregorian calendar — 13 days apart for 1900-2099. Q: What is a Julian Day Number? A: The Julian Day Number is a continuous count of days used by astronomers, independent of any calendar. This tool shows it so you can chain conversions or compute exact day intervals. Q: Is my date sent anywhere? A: No. The conversion runs entirely in your browser using local arithmetic — nothing is uploaded or stored. #### Hebrew Calendar Converter URL: https://geratools.com/hebrew-calendar-converter Free Hebrew calendar converter. Enter any Gregorian date and get the matching Hebrew (Jewish) date — day, month and Anno Mundi year — using the fixed molad-based calendar. Privacy-first and runs entirely in your browser. How to use: 1. Pick the Gregorian date: Choose any date with the date picker. 2. Read the Hebrew date: The tool shows the day, Hebrew month and Anno Mundi (AM) year instantly. 3. Mind the sunset: Remember the Hebrew day starts at sunset, so a civil date near nightfall may map to the next Hebrew day. FAQ: Q: How does the Hebrew calendar handle leap years? A: The Hebrew calendar adds a 13th month in 7 of every 19 years, splitting Adar into Adar I and Adar II. This converter applies the fixed molad-based rules including the four postponements (dehiyyot), so leap years and month lengths are computed correctly. Q: What is the Anno Mundi (AM) year? A: Anno Mundi means "in the year of the world" — the Hebrew calendar counts years from the traditional date of creation. The Gregorian year 2026 corresponds roughly to AM 5786/5787, with the changeover at Rosh Hashanah in the autumn. Q: Why does the Hebrew year change in autumn, not January? A: The Hebrew year begins on Rosh Hashanah (1 Tishrei), which falls in September or October. So a Gregorian date in, say, November has a different AM year than the same Gregorian year in March. Q: How many days are in a Hebrew month? A: Months alternate between 29 and 30 days, and two months (Cheshvan and Kislev) can vary to keep the calendar aligned. A common year runs 353–355 days and a leap year 383–385 days, depending on the postponement rules. Q: How accurate is this converter? A: It uses the standard arithmetic (fixed) Hebrew calendar via the Julian Day Number, matching the calendar in universal civil and religious use. The Hebrew day begins at sunset, so dates after nightfall belong to the following Hebrew day. Q: Does my date leave my device? A: No. The converter is privacy-first — every calculation runs locally in your browser and nothing is sent or stored. #### Persian (Jalali) Calendar Converter URL: https://geratools.com/persian-jalali-converter Free Persian (Jalali / Solar Hijri) calendar converter. Convert any date between the Gregorian and Persian calendars in both directions, with the weekday. Privacy-first and runs entirely in your browser — nothing is sent anywhere. How to use: 1. Choose the direction: Select Gregorian to Persian, or Persian to Gregorian. 2. Enter the date: Pick a Gregorian date, or enter the day, Persian month and year. 3. Read the result: The matching date and weekday appear instantly. FAQ: Q: Is the Persian calendar the same as the Solar Hijri calendar? A: Yes. The Persian (Jalali / Shamsi) calendar is the Solar Hijri calendar used in Iran and Afghanistan. Its year begins at the spring equinox (Nowruz), and the first six months have 31 days, the next five have 30, and Esfand has 29 or 30. Q: How accurate is the conversion? A: It uses Borkowski's 33-year-cycle algorithm, which exactly matches the observational Solar Hijri calendar across the full modern range, pivoting through the Julian Day Number. Round-trips are exact. Q: When does the Persian year start? A: The Persian year begins on 1 Farvardin, which falls on the March equinox — Nowruz — around 20 or 21 March in the Gregorian calendar. That day is Persian New Year. Q: What are the Persian months? A: The twelve months are Farvardin, Ordibehesht, Khordad, Tir, Mordad, Shahrivar, Mehr, Aban, Azar, Dey, Bahman and Esfand. The first six have 31 days, the next five have 30, and Esfand has 29 days (30 in a leap year). Q: How does a Persian leap year work? A: A Persian leap year adds a 30th day to Esfand. Leap years follow a 33-year cycle tied to the astronomical equinox, which is why the algorithm-based conversion is needed for exactness rather than a fixed rule. Q: Why is the Persian year about 621 less than the Gregorian year? A: The Solar Hijri epoch is the year of the Prophet's migration (Hijra) measured in solar years, so Persian year numbers run roughly 621–622 behind the Gregorian year for the same date. Q: Is my date uploaded anywhere? A: No. The converter is privacy-first — all calculation happens locally in your browser and nothing is transmitted or stored. #### Ethiopian Calendar Converter URL: https://geratools.com/ethiopian-calendar-converter Free Ethiopian calendar converter. Convert any date between the Gregorian and Ethiopian (Amete Mihret) calendars in both directions, including the 13th month Pagume. Privacy-first and runs entirely in your browser. How to use: 1. Choose the direction: Select Gregorian to Ethiopian, or Ethiopian to Gregorian. 2. Enter the date: Pick a Gregorian date, or enter the day, Ethiopian month and year. 3. Read the result: The matching date and weekday appear instantly, including dates in Pagume. FAQ: Q: Why does the Ethiopian year differ from the Gregorian by 7 or 8 years? A: The Ethiopian calendar (Amete Mihret) counts from a different reckoning of the Annunciation, so its year is about 7 to 8 years behind the Gregorian year. It has 12 months of 30 days plus a 13th month, Pagume, of 5 days (6 in a leap year). Q: How accurate is the conversion? A: It uses the standard Ethiopian arithmetic — leap when the year mod 4 equals 3 — pivoting through the Julian Day Number, so conversions are exact and round-trip perfectly. The same rules apply to the Eritrean calendar. Q: Does my date leave my browser? A: No. The converter is privacy-first — every calculation runs locally in your browser and nothing is sent or stored. Q: How many months does the Ethiopian calendar have? A: Thirteen. Twelve months of exactly 30 days each, plus a short 13th month called Pagume of 5 days, or 6 days in a leap year. This is why Ethiopia is sometimes described as having "13 months of sunshine." Q: When does the Ethiopian new year fall? A: Ethiopian New Year (Enkutatash), the 1st of Meskerem, falls on 11 September in the Gregorian calendar, or 12 September in the year before a Gregorian leap year. Q: How do I convert an Ethiopian year to a Gregorian year? A: Add roughly 7 to 8 years. Before the Ethiopian new year (around 11 September) add 8; on or after it add 7. So Ethiopian year 2018 corresponds to late 2025 into 2026 Gregorian. Q: When is an Ethiopian leap year? A: An Ethiopian year is a leap year when the year number divided by 4 leaves a remainder of 3. In a leap year Pagume has 6 days instead of 5. The Ethiopian leap day precedes the Gregorian one by several months. Q: Does this also work for the Eritrean calendar? A: Yes. Eritrea uses the same Ge'ez calendar with identical month lengths and leap rules, so every conversion here applies equally to Eritrean dates. #### Thai Buddhist Date Converter (BE ⇄ CE) URL: https://geratools.com/thai-buddhist-date-converter Free Thai Buddhist calendar converter. Convert any Gregorian (CE) date to the Thai Buddhist Era (BE / พ.ศ.) and back — Buddhist Era = Common Era + 543. Privacy-first and runs entirely in your browser; nothing is sent anywhere. How to use: 1. Pick a direction: Choose whether to convert a Gregorian date to the Thai Buddhist Era, or a Buddhist Era date back to Gregorian. 2. Enter the date: Select a Gregorian date, or type the Buddhist Era day, month and year. 3. Read the result: The tool shows the converted date — only the year changes, since the Thai solar calendar shares the same day and month as the Gregorian calendar. FAQ: Q: How does the Thai Buddhist Era relate to the Gregorian year? A: The Buddhist Era (BE / พ.ศ.) is the Common Era (CE / ค.ศ.) plus 543. For example, 2026 CE is 2569 BE. Since 1941 the Thai solar calendar uses the same day and month as the Gregorian calendar, so only the year differs. Q: Is the conversion accurate? A: Yes. For dates from 1941 onward the Thai solar calendar is identical to the Gregorian calendar except for the +543 year offset, so the conversion is exact and deterministic. Q: Is my date sent anywhere? A: No. The converter is privacy-first — every calculation happens locally in your browser and no date ever leaves your device. Q: How do I convert a BE year to CE? A: Subtract 543. For example, 2569 BE − 543 = 2026 CE. To go the other way, add 543 to the Gregorian year. Q: Do the day and month change when converting? A: No. Since 1941 the Thai solar calendar shares the same day and month as the Gregorian calendar, so a date converts by changing only the year — 28 May stays 28 May. Q: Why is the offset 543 and not 544? A: The Buddhist Era counts from the year of the Buddha's passing. Thailand's official BE-to-CE offset for the solar calendar is a fixed 543 years, which this tool applies directly. Q: Does this handle Thai lunar dates or festivals? A: No. This converter is for the everyday Thai solar (Suriyakati) calendar. Traditional lunar festival dates like Songkran's lunar reckoning are not computed here. #### Nepali Bikram Sambat Converter (BS ⇄ AD) URL: https://geratools.com/nepali-bikram-sambat-converter Free Nepali Bikram Sambat (BS / बिक्रम सम्बत) date converter. Convert any Gregorian (AD) date to Bikram Sambat and back, using the published per-year Nepali calendar table. Privacy-first and runs entirely in your browser; nothing is sent anywhere. How to use: 1. Pick a direction: Choose whether to convert a Gregorian (AD) date to Bikram Sambat, or a BS date back to Gregorian. 2. Enter the date: Select a Gregorian date, or type the BS day, choose the month (Baisakh to Chaitra) and enter the BS year. 3. Read the result: The converter shows the corresponding date in the other calendar. FAQ: Q: Why can't Bikram Sambat use a simple year offset? A: Unlike the Thai Buddhist calendar, Bikram Sambat month lengths range from 29 to 32 days and change from year to year. A fixed offset would drift, so the converter uses the published per-year table of month lengths, anchored at 1 Baisakh 2000 = 14 April 1943. Q: How accurate is the conversion and what range is supported? A: The conversion is exact within the supported range of BS 2000 to 2089 (approximately AD 1943 to 2033) because it walks the official Nepali calendar table via the Julian Day Number. Dates outside that range are not converted. Q: What are the months of the Bikram Sambat calendar? A: The twelve BS months in order are Baisakh, Jestha, Ashadh, Shrawan, Bhadra, Ashwin, Kartik, Mangsir, Poush, Magh, Falgun and Chaitra. The year begins in mid-April with 1 Baisakh. Q: How many years ahead is Bikram Sambat compared with the Gregorian year? A: Bikram Sambat runs roughly 56 to 57 years ahead of the Gregorian calendar. The exact gap shifts within a year because the BS new year falls in mid-April rather than 1 January. Q: When does the Nepali new year fall? A: The Nepali new year, 1 Baisakh, falls in mid-April of the Gregorian calendar — around 13 or 14 April. It is a public holiday in Nepal. Q: Is Bikram Sambat the same as Vikram Samvat? A: They share the same era and root, but the Nepali Bikram Sambat used officially in Nepal is a solar calendar with month lengths that vary year to year. The Indian Vikram Samvat is largely lunisolar, so the two diverge in day-to-day dates despite the common name. Q: Is my date sent anywhere? A: No. The converter is privacy-first — all processing happens locally in your browser and no date ever leaves your device. #### Unit Price Comparison Calculator URL: https://geratools.com/unit-price-comparison Free unit price comparison calculator. Enter the price and pack size of several products and instantly see the price per 100 g, per litre or per item, with the best value highlighted. Privacy-first — all calculations run in your browser. How to use: 1. Enter each product: Add a row for each option and type its price and pack size, then pick the unit (grams, kilograms, ounces, pounds, millilitres, litres, fluid ounces, gallons, or each). 2. Read the unit price: The tool normalises each item to a common base and shows the price per 100 g, per litre or per item so you can compare different pack sizes fairly. 3. Spot the best value: The lowest unit price in each measurement group is highlighted in green and labelled "best". FAQ: Q: How is the unit price calculated? A: Each item's quantity is converted to a base unit — grams for weight, millilitres for volume, or a single item for count — then the price is divided by that base quantity. The result is shown per 100 g, per litre or per item for readability. Q: Can I compare weight against volume? A: Only items measured the same way are compared directly, because a gram and a millilitre are not interchangeable. If you mix weight, volume and count, the tool highlights the best value within each group separately and shows a note. Q: Are my prices sent anywhere? A: No. Every conversion and comparison is computed locally in your browser. Your prices and quantities are never uploaded or stored. Q: Why is the bigger pack not always cheaper per unit? A: Retailers often price larger packs at a higher unit cost than mid-size ones, a pattern sometimes called the bulk-buying trap. Calculating the price per 100 g or per litre reveals it: a 1 kg pack can be dearer per unit than a 500 g one. Q: How do I compare a kilogram pack with a gram pack? A: Enter each with its own unit — one in kg, one in g. The calculator converts both to grams internally and shows each as a price per 100 g, so the different pack sizes line up on one scale. Q: What units does the calculator support? A: Weight: grams, kilograms, ounces and pounds. Volume: millilitres, litres, US fluid ounces and US gallons. Count: a simple each / item. Weight is normalised to grams, volume to millilitres, and count to one item. Q: Can I compare items sold by weight against items sold by count? A: Not directly, because a price per gram and a price per item measure different things. The tool groups by measurement type and highlights the best value separately within weight, volume and count. #### Tonnes to Kilograms Converter URL: https://geratools.com/tonnes-to-kilograms Free Tonnes to Kilograms converter. Type a value in either field for an instant result. Formula: 1 metric tonne = 1000 kg. Runs entirely in your browser — no data sent to any server. How to use: 1. Enter your tonnes value: Type the amount in the Tonnes field. The Kilograms result updates instantly as you type. 2. Or enter the kilograms value: You can also type directly into the Kilograms field — the converter works in both directions at once. 3. Read the result: The converted value appears immediately. Use the reference table below for common mass conversion values. FAQ: Q: How do I convert tonnes to kilograms? A: Multiply the number of metric tonnes by 1000. For example, 1 t equals 1000 kg, and 2.5 t equals 2500 kg. Q: How many kilograms are in one tonne? A: There are exactly 1000 kilograms in one metric tonne (1 t = 1000 kg). Q: Is anything uploaded? A: No — every conversion runs locally in your browser and nothing is sent to any server. Q: How do I convert kilograms back to tonnes? A: Divide the kilograms by 1000. For example, 7500 kg ÷ 1000 = 7.5 t. Just type into the Kilograms field and the Tonnes value updates. Q: Is a metric tonne the same as a US or UK ton? A: No. A metric tonne is exactly 1000 kg. A US (short) ton is about 907.18 kg and a UK (long) ton about 1016.05 kg. This tool converts metric tonnes only. Q: Is the conversion exact? A: Yes. The metric tonne is defined as exactly 1000 kilograms, so the factor of 1000 is exact with no rounding. Q: What is the symbol for tonne? A: The symbol is t. The metric tonne is also written as megagram (Mg), since 1 t equals one million grams. #### Alcohol Units Calculator URL: https://geratools.com/alcohol-units-calculator Free alcohol units calculator. Work out UK units and US standard drinks for any drink from its volume and ABV, with presets for beer, wine and spirits. Runs entirely in your browser. How to use: 1. Pick a drink: Choose a preset for beer, wine or spirits, or select Custom. 2. Adjust volume and ABV: Set the volume in ml and the alcohol by volume percentage shown on the label. 3. Enter how many: Set the number of drinks and read the total UK units and US standard drinks. FAQ: Q: How is a UK alcohol unit calculated? A: One UK unit is 10 ml of pure alcohol. Units equal the volume in ml times the ABV percentage divided by 1000. For example, a 568 ml pint at 4% ABV is 568 × 4 ÷ 1000 = 2.3 units. Q: How does that relate to US standard drinks? A: A US standard drink contains 14 grams of pure alcohol. We convert from millilitres of ethanol using a density of 0.789 g/ml, so one UK unit (about 7.9 g) is roughly 0.56 US standard drinks. Q: Is my data sent anywhere? A: No. All calculations run locally in your browser and nothing is uploaded. Q: How many units are in a bottle of wine? A: A standard 750 ml bottle of 13% wine contains 750 × 13 ÷ 1000 = 9.75 units, just under the entire 14-unit weekly low-risk guideline in one bottle. Q: Is 14 units a week a lot? A: 14 units is the UK Chief Medical Officers' weekly low-risk guideline for both men and women. They advise spreading it over three or more days and having several drink-free days, rather than saving it all for one session. #### Frame Rate Converter URL: https://geratools.com/frame-rate-converter Convert between video frame rates (e.g. 23.976 to 29.97 fps), find the rate ratio, and recalculate frame counts for the same duration. Browser-only, nothing uploaded. How to use: 1. Enter the source frame rate: Type or pick the original frame rate in fps, such as 23.976. 2. Enter the target frame rate: Type or pick the destination frame rate, such as 29.97. 3. Enter a frame count: Add a frame count to see the equivalent number of frames for the same duration at the new rate. FAQ: Q: What is the difference between 24 and 23.976 fps? A: They differ by a factor of exactly 1000/1001. 23.976 fps is 24 multiplied by 1000/1001, the NTSC pulldown adjustment used to fit film into the NTSC colour standard. The same factor links 30 and 29.97 fps. Q: How do I convert a frame count between rates? A: Divide the frame count by the source fps to get the duration in seconds, then multiply by the target fps. This tool does it for you and shows the duration too. Q: What is the rate ratio used for? A: The ratio of target fps to source fps tells you how frame counts and speed scale between the two rates. A ratio above 1 means the target rate packs more frames into the same second; below 1 means fewer. Q: Why is 23.976 fps used instead of 24? A: It dates from the NTSC colour standard, which slowed the original 30 fps to 29.97 (a 1000/1001 reduction) to avoid interference between the colour and sound carriers. The same 1000/1001 factor turns 24 fps film into 23.976 fps for NTSC delivery. Q: Is any video uploaded? A: No. The tool only does arithmetic on the numbers you type, entirely in your browser. #### Months to Weeks Converter URL: https://geratools.com/months-to-weeks Free months-to-weeks converter. Turn months into weeks using the average month (30.436875 days, about 4.3481 weeks), and swap to convert weeks back to months. Runs entirely in your browser. How to use: 1. Enter the number of months: Type how many months you want to convert into the input field. 2. Read the weeks: The equivalent number of weeks appears instantly, using the average month of about 4.3481 weeks. 3. Swap if needed: Press Swap to convert in the other direction, from weeks back to months. FAQ: Q: How many weeks are in a month? A: Calendar months vary (28 to 31 days), so there is no single answer. This tool uses the average Gregorian month — 365.2425 ÷ 12 = 30.436875 days, which is about 4.3481 weeks per month. Q: Why is the result not a whole number? A: Because a month is not an exact number of weeks. One month averages roughly 4.35 weeks, so 3 months is about 13.04 weeks rather than a round figure. Q: How many weeks is 3 months? A: 3 × 4.348125 = 13.04 weeks. People often say '13 weeks' for a quarter, which is very close to the exact average. Q: How many weeks is 9 months of pregnancy? A: Using the average month, 9 months ≈ 39.1 weeks. Pregnancy is usually tracked as 40 weeks, which is why '9 months' is an approximation rather than an exact match. Q: How do I convert weeks back to months? A: Divide by 4.348125. For example, 26 weeks ÷ 4.348125 ≈ 5.98 months. Press Swap and the tool does this automatically. Q: Is my input uploaded anywhere? A: No — the conversion runs entirely in your browser and nothing is sent over the network. #### Cups to Grams Rice Converter URL: https://geratools.com/cups-to-grams-rice Free cups-to-grams converter for rice, by type (white, brown, basmati). Converts both ways. Runs entirely in your browser — no data sent to any server. How to use: 1. Pick your rice type: Choose the rice type — densities differ between long-grain, short-grain, brown and basmati. 2. Choose a direction: Convert cups to grams, or switch to grams to cups for the reverse calculation. 3. Enter the amount: Type your value and the converted weight or volume updates instantly. FAQ: Q: How many grams are in a cup of rice? A: About 185 g for white long-grain rice and 200 g for white short-grain, per US cup of uncooked rice. Densities vary by type and brand, so weighing gives the best accuracy. Q: Does the rice type change the conversion? A: Yes — different grains pack differently. This tool uses 185 g/cup for white long-grain, 200 g/cup for short-grain, 190 g/cup for brown and 180 g/cup for basmati. Q: How many grams is half a cup of rice? A: About 92.5 g of uncooked white long-grain rice (185 ÷ 2). For short-grain it is 100 g, for brown 95 g and for basmati 90 g. Q: Should I measure rice cooked or uncooked? A: These figures are for uncooked rice, since that is how recipes usually specify it. Cooked rice absorbs water and weighs roughly two to three times more per cup. Q: Is anything uploaded? A: No — every conversion happens locally in your browser, with no data sent to any server. #### Weighted Random Picker URL: https://geratools.com/weighted-random-picker Free weighted random picker. Give each name or option its own weight, draw one or many winners with cryptographically-fair odds, run no-repeat draws, and watch expected-vs-observed frequency build up. Everything runs in your browser — nothing is uploaded. How to use: 1. Add your entries: Type each name or option and set a weight. A weight of 3 is three times as likely to be picked as a weight of 1. 2. Choose how many to draw: Set picks per draw, and turn on no-repeat if a single draw should never pick the same entry twice. 3. Draw and review: Press Draw for a cryptographically-fair pick. The history table and the expected-vs-observed chart update after every draw, and you can export the full log to CSV. FAQ: Q: What does the weight actually do? A: The weight sets the relative chance of each entry being chosen. The tool sums all weights, then picks a point uniformly across that total — so an entry with weight 3 in a pool summing to 10 has a 30% chance per pick. Weights can be whole numbers or decimals, and a weight of 0 excludes an entry without deleting it. Q: Is the randomness genuinely fair? A: Yes. Each pick uses the browser Web Crypto API (crypto.getRandomValues), which is a cryptographically secure random source — far stronger than Math.random. The weighted-selection algorithm walks the cumulative weights so the long-run frequency matches the weights you set, which you can confirm in the expected-vs-observed panel. Q: What is the difference between no-repeat and remove-after-pick? A: No-repeat applies within a single draw — if you draw 3 winners it guarantees 3 different entries. Remove-after-pick is permanent — winners are deleted from the list after the draw, which is what you want for sequential raffle rounds or door prizes where each name can only win once overall. Q: Can I import a long list of names quickly? A: Yes. Open Bulk import and paste one entry per line. Add a weight after a comma or space (for example "Alice, 3") or leave it off to default to weight 1. Importing replaces the current list, so you start from a clean pool. Q: Why do observed percentages not exactly match the expected ones? A: Random outcomes only converge on the expected odds over many draws — small sample sizes naturally wobble. After a handful of draws an entry weighted at 20% might show 0% or 40%; after a few hundred it will settle close to 20%. The chart makes this convergence visible, which is a useful sanity check. Q: Is my data private? A: Completely. Entries, weights and draw history are stored only in your browser localStorage and the random draws happen on-device. Nothing is ever sent to a server, so you can use it for confidential giveaways, internal rotas or sensitive selections. #### Area Converter URL: https://geratools.com/area-converter Free online area converter. Type any value and instantly see it in square millimetres, centimetres, metres, hectares, square kilometres, square inches, feet, yards, acres and square miles. Live cross-fill, swap button and a reference table. 100% in your browser. How to use: 1. Pick your from and to units: Choose the unit you are converting from and the unit you want the answer in — metric units like m² and hectares, or imperial units like square feet and acres. 2. Type a value into any field: Enter a number in any of the live fields. Every other unit recalculates instantly so you can read the value in all ten units at once. 3. Swap or read the grid: Use the swap button to reverse the from and to units, or scan the full result grid and reference table for every conversion at a glance. FAQ: Q: How many square feet are in a square metre? A: One square metre equals about 10.7639 square feet, because one foot is exactly 0.3048 metres and area scales with the square of length (0.3048² = 0.09290304 m² per square foot). Q: How many square metres are in an acre? A: One acre equals exactly 4,046.8564224 square metres. An acre is defined as 43,560 square feet, and each square foot is 0.09290304 m², so 43,560 × 0.09290304 = 4,046.8564224 m². Q: How do I convert hectares to acres? A: One hectare is 10,000 square metres, which is about 2.4711 acres. To go the other way, one acre is roughly 0.4047 hectares. The converter does both directions exactly. Q: How many acres are in a square mile? A: A square mile contains exactly 640 acres. One mile is 1,609.344 metres, so a square mile is 1,609.344² = 2,589,988.110336 m², which divided by 4,046.8564224 m² per acre gives 640. Q: Why does area scale with the square of length? A: Area is length multiplied by width. If you double a length unit, both sides of a square double, so the area becomes four times larger. That is why the inch-to-metre factor of 0.0254 becomes 0.0254² = 0.00064516 for square inches. Q: Is my data sent anywhere? A: No. Every conversion is pure arithmetic that runs entirely in your browser. No values are uploaded, logged or stored on any server. #### Temperature Converter URL: https://geratools.com/temperature-converter Free temperature converter for Celsius, Fahrenheit, Kelvin and Rankine. Type into any field and all the others update live, with a swap button and a full reference table. Runs entirely in your browser. How to use: 1. Type a temperature: Enter a number in the Temperature field, or directly into any of the four scale boxes below. 2. Pick the from and to scales: Choose the scale you are starting from and the one you want, then read the highlighted result. 3. Read every scale at once: The four cards show Celsius, Fahrenheit, Kelvin and Rankine simultaneously; typing into any one re-anchors all of them. 4. Swap if needed: Use the swap button to flip the from and to scales while keeping the same physical temperature. FAQ: Q: How do I convert Celsius to Fahrenheit? A: Multiply the Celsius value by 9/5 and add 32. So 20 °C becomes 20 × 9/5 + 32 = 68 °F. To go the other way, subtract 32 first then multiply by 5/9. Q: How do I convert Celsius to Kelvin? A: Add 273.15 to the Celsius value. 25 °C is 298.15 K. Kelvin uses the same degree size as Celsius, so the gap between two temperatures is identical in both scales — only the zero point differs. Q: What is the Rankine scale and how does it relate to Fahrenheit? A: Rankine is an absolute scale that starts at absolute zero but uses Fahrenheit-sized degrees. Convert from Fahrenheit by adding 459.67, so 32 °F equals 491.67 °R. It is mostly used in some US engineering and thermodynamics work. Q: At what temperature are Celsius and Fahrenheit equal? A: They read the same at −40, where −40 °C equals −40 °F. This is the single crossover point of the two scales and a handy sanity check for any converter. Q: What is absolute zero on each scale? A: Absolute zero is 0 K, which equals −273.15 °C, −459.67 °F and 0 °R. Nothing can be colder, so the tool flags any value that would fall below it as physically impossible. Q: Is my data sent anywhere? A: No. Every conversion is pure arithmetic performed in your browser using built-in JavaScript. No values are uploaded, logged or stored on a server. #### Weight & Mass Converter URL: https://geratools.com/weight-converter Free weight and mass converter. Convert between mg, g, kg, tonne, ounce, pound, stone, US ton and imperial ton with a live grid — type any unit and every other updates instantly. 100% in your browser, nothing uploaded. How to use: 1. Pick a from and to unit: Choose any two units in the top row — the focused result line shows the direct conversion with a swap button. 2. Type a value into the live grid: Type into any unit field in the grid below and every other unit recalculates instantly from the same mass. 3. Swap or compare: Press the swap button to reverse the from and to units, or read every equivalent at once in the grid. FAQ: Q: How many grams are in a pound? A: Exactly 453.59237 grams. This is the international avoirdupois pound, agreed in 1959, and every imperial unit in this tool is derived from it. Q: How many pounds are in a kilogram? A: One kilogram is about 2.2046226218 pounds. So 70 kg is roughly 154.32 lb. The converter carries full precision and only rounds for display. Q: What is the difference between a US ton and an imperial ton? A: A US (short) ton is 2000 pounds (about 907.18 kg). An imperial (long) ton is 2240 pounds (about 1016.05 kg). A metric tonne is 1000 kg, different again from both. Q: How many kilograms are in a stone? A: One stone equals 14 pounds, which is 6.35029318 kg. So 12 stone is about 76.20 kg. Stones are still common for body weight in the UK and Ireland. Q: How many ounces are in a gram? A: One gram is about 0.035274 ounces, and one ounce is exactly 28.349523125 grams. Type a value into either the gram or ounce field to see the exact equivalent. Q: Is my data sent anywhere? A: No. Every conversion is pure arithmetic that runs entirely in your browser. No values are uploaded, logged or stored on any server. #### Julian Date Converter URL: https://geratools.com/julian-date-converter Free Julian Date converter. Enter a Gregorian date and UTC time to get the Julian Date (JD), Julian Day Number (JDN), Modified Julian Date (MJD), J2000.0 offset, day of week, and the equivalent Old-Style Julian calendar date. Reverse conversion included. Runs entirely client-side — no data is uploaded. How to use: 1. Choose a conversion direction: Select either "Gregorian date to Julian Date" or "Julian Date to Gregorian date" from the dropdown. 2. Enter your date or JD value: For Gregorian input pick the date and type the UTC hour, minute, and second. For JD input type the decimal Julian Date value. 3. Read all derived quantities: The panel shows JD, JDN, MJD, J2000.0 offset, day of week, the back-converted Gregorian datetime, and the equivalent Julian-calendar (Old Style) date. 4. Copy the Julian Date: Hit the Copy JD button to copy the decimal JD to your clipboard for use in calculations or scripts. FAQ: Q: What is a Julian Date (JD)? A: A Julian Date is a continuous count of days and fractional days since noon UTC on 1 January 4713 BC (in the proleptic Julian calendar). Unlike calendar dates, a JD is a single decimal number, so the time between any two events is just a subtraction. For example, JD 2451545.0 is exactly 2000-01-01 at 12:00 UTC — the standard J2000.0 epoch used in orbital mechanics. Q: What is the difference between JD, JDN, and MJD? A: The Julian Day Number (JDN) is the integer part: it increments at noon UTC and counts whole days. The Julian Date (JD) adds the fractional part — a value between 0 and 1 representing the fraction of a day past the preceding noon. The Modified Julian Date (MJD) is JD minus 2,400,000.5, which shifts the day boundary from noon to midnight and gives more compact numbers for modern dates (e.g. MJD 51544.5 = J2000.0). Q: How is the Julian Date calculated from a Gregorian date? A: The JDN is found with the Richards / Fliegel-Van Flandern integer formula: given year Y, month M, day D, compute a = floor((14 - M) / 12), then JDN = D + floor((153*(M + 12*a - 3) + 2) / 5) + 365*(Y + 4800 - a) + floor((Y+4800-a)/4) - floor((Y+4800-a)/100) + floor((Y+4800-a)/400) - 32045. The fractional day is (hour - 12)/24 + minute/1440 + second/86400, and JD = JDN + fraction. Q: What is the J2000.0 epoch? A: J2000.0 is the standard astronomical reference epoch defined as JD 2451545.0, which corresponds to 2000 January 1.5 TT (Terrestrial Time, approximately 2000-01-01 12:00:00 UTC). Orbital elements, star catalogues, and coordinate systems are often specified at J2000.0. The J2000.0 offset shown by this tool is simply JD minus 2451545.0 in days. Q: What is the Julian calendar date shown as "O.S."? A: O.S. stands for Old Style — the proleptic Julian calendar, which predates the Gregorian reform of 1582. Before October 1582, the Julian and Gregorian calendars agree on day numbering but not on the date: for example, the same moment that is 2000-01-01 in the Gregorian calendar is December 19, 1999 in the Julian calendar (they drift by ~13 days in the modern era). Historical events in Russia, Greece, and other countries that adopted the Gregorian calendar late are often recorded in Old Style dates. Q: Why does the Julian Date increment at noon instead of midnight? A: The convention dates from the early history of astronomy. When the Julian Day system was introduced in 1583 by Joseph Justus Scaliger, astronomical observations were typically made at night and recorded by date. Starting the JD count at noon meant that a single night of observations always fell within a single Julian Day, avoiding the ambiguity of a midnight boundary splitting one observation session across two calendar days. ### Date & Time #### Age Calculator URL: https://geratools.com/age-calculator Free age calculator. Enter your date of birth and instantly see your exact age in years, months and days, total days, weeks and hours lived, and a countdown to your next birthday. Runs entirely in your browser. How to use: 1. Enter your date of birth: Click the date field and pick your date of birth, or type it in YYYY-MM-DD format. The calculator accepts any date from the distant past up to today. 2. Read your exact age: Your age in years, months, and remaining days appears instantly, along with total days, weeks, and hours you have been alive. 3. Check your next birthday: The next-birthday row shows the exact calendar date and how many days away it is. FAQ: Q: How is the exact age calculated? A: The calculator subtracts your date of birth from today's date, accounting for varying month lengths and leap years. The result is expressed as complete years, complete months, and remaining days — not just a rounded year count. Q: How does the months-and-days breakdown handle different month lengths? A: When today's day-of-month is earlier than your birth day, the tool borrows the number of days in the previous calendar month, then carries down a month. This is why the same age can show 29, 30 or 31 "borrowed" days depending on which months are involved. Q: Are leap years counted correctly? A: Yes. The total-days figure is the true number of calendar days between the two dates, so every 29 February you have lived through is included automatically. Q: How is the next-birthday countdown worked out? A: The tool builds your birthday in the current year; if that date has already passed (or is today), it rolls forward to next year, then counts the whole days until then. On the day itself it shows "Today!". Q: How many days are there in a year of age? A: A common (non-leap) year has 365 days and a leap year 366, so an average year is about 365.25 days. The calculator does not approximate — it counts the exact days between your birth date and today. Q: Is my date of birth stored or sent anywhere? A: No. The calculation runs entirely in your browser using JavaScript's built-in Date object. Your date of birth is never transmitted to a server, stored in a database, or logged in any way. #### Beers Criteria High-Risk Drug Checker for Older Adults URL: https://geratools.com/ags-beers-criteria-age-checker Check a drug name against a curated subset of the 2023 AGS Beers Criteria for potentially inappropriate medications in adults aged 65 and over, returning an avoid or use-with-caution rating and the evidence-based reason for concern. How to use: 1. Enter the drug name: Type the generic name or a common brand name of the medication you want to check. 2. Read the rating: The tool returns an avoid or use-with-caution rating for adults aged 65 and over, or tells you the drug is not in this reference subset. 3. Review the reason: Read the evidence-based reason for concern, then apply clinical judgement and a full medication review for your individual patient. FAQ: Q: What are the Beers Criteria? A: The American Geriatrics Society Beers Criteria are an evidence-based list of medications that are potentially inappropriate for adults aged 65 and over. They flag drugs whose risks often outweigh benefits in older people, supporting safer prescribing and deprescribing. Q: Does a flag mean I must stop the drug? A: No. Beers Criteria are recommendations, not absolute bans. A flagged medication can still be appropriate for a specific patient after weighing benefit, risk, alternatives, and the patient's preferences. The tool supports, but does not replace, clinical judgement. Q: Is this the complete Beers list? A: No. This tool covers a curated subset of the most commonly encountered 2023 AGS Beers entries, such as anticholinergics, benzodiazepines, long-acting sulfonylureas, and certain NSAIDs. A no-match result does not guarantee safety; consult the full criteria. Q: Why are anticholinergic drugs singled out? A: Drugs with strong anticholinergic activity, like diphenhydramine, amitriptyline, and oxybutynin, cause confusion, dry mouth, constipation, urinary retention, and falls in older adults, and the effects accumulate when several are combined. The criteria flag them prominently. Q: Can I search by brand name? A: Yes. The checker recognises common brand names alongside generic names, so searching for a familiar trade name will usually match the underlying drug. When in doubt, search the generic name for the most reliable match. #### Chicken Egg Incubation Due Date Calculator URL: https://geratools.com/chicken-egg-incubation-calculator Enter the date eggs were set and the species (chicken 21 days, duck 28, quail 17, goose 30, turkey 28) to compute the lockdown date, expected hatch date, and an egg-turning schedule. For backyard chicken and waterfowl hatchers. How to use: 1. Enter the set date: Pick the calendar date you placed the eggs in the incubator. This is day zero of incubation. 2. Choose the species: Select the bird species so the tool uses the correct incubation period, from 17 days for quail to 30 for geese. 3. Read your key dates: The tool shows the lockdown date (stop turning, raise humidity) three days before hatch, and the expected hatch date, plus the turning window. FAQ: Q: How many days does a chicken egg take to hatch? A: Chicken eggs hatch in 21 days at the correct temperature of about 37.5 C (99.5 F) in a forced-air incubator. Other species differ: quail 17 to 18 days, duck 28, turkey 28, goose 28 to 30. The tool uses each species' standard period. Q: What is lockdown? A: Lockdown is the final three days before hatch when you stop turning the eggs, raise humidity to around 65 to 70 percent, and avoid opening the incubator. This calculator marks lockdown at the incubation period minus three days from your set date. Q: When should I stop turning the eggs? A: Stop turning at lockdown, three days before the hatch date. Until then, turn eggs an odd number of times per day (at least three, ideally five) so the embryo does not stick to the shell membrane. Auto-turners can run continuously until lockdown. Q: Are the hatch dates exact? A: They are expected dates based on standard incubation periods and correct temperature. Eggs may hatch a day early or late depending on temperature stability, egg size, and storage before setting. Do not give up on viable-looking eggs for two or three extra days. Q: Does egg storage before setting affect the timeline? A: Yes. Eggs stored more than a week before setting can hatch slightly late and at lower rates. Store hatching eggs pointy-end down at 12 to 15 C and set them within seven days for the best results; the incubation clock only starts when they go into the warm incubator. #### Growing Degree Days (GDD) Calculator URL: https://geratools.com/growing-degree-days-calculator Calculate daily and accumulated Growing Degree Days using the (Tmax + Tmin)/2 minus base-temperature formula, with crop presets and upper/lower temperature caps for corn, wheat, and soybeans. Time pesticide, scouting, and harvest operations precisely. How to use: 1. Pick a crop preset: Choose corn, wheat, soybeans, or custom to set the correct base temperature and upper/lower caps automatically. 2. Enter daily highs and lows: Type one Tmax and Tmin pair per line for each day of the period you want to accumulate, in degrees Fahrenheit. 3. Read accumulated GDDs: The tool caps each day at the crop limits, averages the high and low, subtracts the base, and sums every day into a season total. FAQ: Q: What is the Growing Degree Day formula? A: GDD for one day equals the average of the daily high and low temperatures minus a crop-specific base temperature. In symbols, GDD = ((Tmax + Tmin) / 2) − Tbase. Negative results are set to zero because development does not run backward below the base. Q: Why are there upper and lower caps? A: Crops stop responding to heat outside a useful range. For corn, any temperature above 86°F is set to 86 and any below 50 is set to 50 before averaging. This modified method prevents very hot days from overstating development. Q: What base temperatures do common crops use? A: Corn and soybeans use a base of 50°F with a cap of 86°F. Small grains such as wheat use a base of 32°F with an upper cap near 77°F. The right base is the temperature below which that crop makes no measurable growth. Q: How do I use accumulated GDDs? A: Seed companies publish GDD requirements for each stage. For example, many corn hybrids need around 1,400 GDDs to silk and 2,700 to reach black layer maturity. Tracking accumulated GDDs lets you predict those dates instead of guessing by calendar. Q: Are GDDs the same as heat units or thermal time? A: Yes, they are different names for the same concept. Heat units, thermal time, and growing degree days all measure accumulated warmth above a base temperature. Make sure the base and any caps match across sources before comparing numbers. #### Resin Casting Shrinkage & Mold Size Calculator URL: https://geratools.com/resin-casting-shrinkage-calculator Enter the finished dimensions you want and your resin's linear shrinkage percentage to compute the oversized mold cavity dimensions, the per-axis oversize, the linear scale factor, and the volume factor for extra resin. For resin artists and small-batch makers. How to use: 1. Enter your finished dimensions: Type the length, width and height you want the cured part to measure, in millimetres. 2. Enter the resin shrinkage: Add your resin's linear shrinkage percentage, usually between 0.1% and 3% from the technical datasheet or a test cast. 3. Build the mold to the cavity size: Make or order the mold cavity at the larger dimensions shown so the part shrinks down to your target as it cures. FAQ: Q: How do I compensate for resin shrinkage? A: Make the mold cavity larger than the finished size you want. Because the part shrinks by a fixed percentage as it cures, the mold dimension equals the finished dimension divided by (1 minus shrinkage over 100). For 1% shrinkage you scale every dimension up by about 1.0101. Q: How much does resin shrink? A: Linear shrinkage is typically 0.1% to 3% depending on the resin type and chemistry. Polyester and some casting resins shrink more, while many epoxy and urethane resins shrink less. Always check the datasheet or measure a test cast for your exact product. Q: Why is the volume factor larger than the linear factor? A: Volume scales with the cube of the linear factor. A 1% linear shrinkage means the part shrinks roughly 3% by volume, so multiply your finished-volume resin estimate by the volume factor to know how much resin the oversized mold actually needs. Q: Does part thickness affect shrinkage? A: Yes. Thicker sections cure hotter and can shrink more, and uneven thickness can cause warping rather than uniform shrinkage. For critical fits, cast a test piece of similar thickness and measure it before committing to a final mold. Q: Should I scale all axes equally? A: Resin shrinkage is generally isotropic, so the same percentage applies to every axis and the tool scales length, width and height by the same factor. If you notice direction-dependent shrinkage in tests, adjust the worst axis individually. #### US Federal Holiday Working Days Counter URL: https://geratools.com/us-federal-holiday-counter Count net working days between two dates excluding all 11 US federal holidays, with correct observed-date rules when a holiday falls on a Saturday or Sunday. Built for payroll, federal-deadline, and SLA calculations. How to use: 1. Pick your date range: Choose a start and end date for the period you want to measure. 2. Read the working-day total: The tool counts every weekday and removes the 11 federal holidays on their observed dates. 3. Check which holidays applied: Expand the list to see each federal holiday deducted and the observed date used. FAQ: Q: What are the 11 US federal holidays? A: New Year's Day, Birthday of Martin Luther King Jr., Washington's Birthday (Presidents' Day), Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day, and Christmas Day. Q: How does the observed-date rule work? A: When a fixed-date federal holiday falls on a Saturday it is observed on the preceding Friday; when it falls on a Sunday it is observed on the following Monday. The tool deducts the observed date, which is the day federal offices actually close. Q: Are floating holidays like Thanksgiving handled correctly? A: Yes. Thanksgiving (fourth Thursday in November), MLK Day (third Monday in January), Presidents' Day (third Monday in February), Memorial Day (last Monday in May), Labor Day (first Monday in September), and Columbus Day (second Monday in October) are computed by weekday rule for the exact year. Q: Does this include state or banking holidays? A: No. This counts the 11 nationwide federal holidays only. Individual states observe additional holidays, and some private employers differ. Add those manually if they apply to you. Q: Is the date range inclusive? A: Yes, both the start and end date are included. If the start date is later than the end date the tool returns zero working days. #### Next Birthday Countdown URL: https://geratools.com/next-birthday-countdown Free next birthday countdown — enter a birth date to find how many days until your next birthday, the age you will turn, and which weekday it lands on. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter your date of birth: Pick the birth date you want to count down to. 2. Read the countdown: See how many days remain until the next occurrence of that birthday. 3. Check the age and weekday: The tool also shows the age you will turn and which day of the week it falls on. FAQ: Q: How are the days until my birthday counted? A: The tool finds the next time your birth month and day occur on or after today, then counts the whole days between today and that date. If the birthday is today, it says so. Q: What happens with a 29 February birthday? A: In years that are not leap years there is no 29 February, so the countdown uses 28 February as the closest matching day for that year. Q: What age will I turn on my next birthday? A: The tool subtracts your birth year from the year of your next birthday. So if your next birthday falls in 2027 and you were born in 1990, it will show that you are turning 37. Q: Does the countdown use my local time zone? A: Yes. The calculation is based on your device's local date at midnight, so the day count matches the calendar where you are. Q: What if my birthday is today? A: If your birth month and day match today, the tool recognises it as your birthday rather than counting zero days, and the next full countdown begins from tomorrow. Q: Is my birth date stored or uploaded? A: No. Everything is calculated in your browser with local date arithmetic — your birth date never leaves your device. #### Days Alive Calculator URL: https://geratools.com/days-alive-calculator Free days alive calculator — enter your date of birth to see how many days, weeks, months, hours and minutes you have been alive. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter your date of birth: Pick your birth date using the date field. 2. Read your total: The number of days you have been alive appears instantly. 3. See other units: Weeks, months, hours and minutes are shown below the day count. FAQ: Q: How is the number of days calculated? A: It measures the whole days between your date of birth and today in your local time zone, then derives weeks, months, hours and minutes from that. Q: Why is the month figure approximate? A: Months vary in length, so the month total uses an average month of 30.44 days. The day count itself is exact. Q: How many days is someone who is 30 years old? A: Roughly 10,957 days, including about 7 or 8 leap days. The exact figure depends on the birth date, which is why this tool counts the real elapsed days rather than multiplying years by 365. Q: Why is the month figure approximate? A: Months vary in length, so the month total uses an average month of 30.44 days (365.25 divided by 12). The day, hour and minute counts are exact. Q: How are weeks and hours worked out? A: Weeks is the day count divided by 7 and rounded down. Hours is days times 24 and minutes is hours times 60, so all three come directly from the exact whole-day total. Q: Can I enter a future date of birth? A: The field caps at today's date, so you cannot pick a future birth date. The tool is designed to count days already lived, not days until a future date. Q: Does it count leap days? A: Yes. Because the count is the real number of days between the two dates, every 29 February you have lived through is automatically included with no separate adjustment. Q: Is my birth date uploaded anywhere? A: No. The calculation runs entirely in your browser and nothing is sent to a server. #### Julian Day Number Calculator URL: https://geratools.com/julian-day-number Convert any Gregorian calendar date and UTC time to its Julian Day Number (JDN), full Julian Date (JD) and Modified Julian Date (MJD). Used in astronomy and computing. Runs entirely in your browser. How to use: 1. Enter a date: Pick a Gregorian calendar date with the date picker. 2. Set the UTC time: Optionally enter the hour and minute in UTC; leave it at noon for the whole-day JDN. 3. Read the results: See the Julian Day Number, the full Julian Date and the Modified Julian Date. FAQ: Q: What is a Julian Day Number? A: The Julian Day Number (JDN) is a continuous count of whole days since noon UTC on 1 January 4713 BC in the proleptic Julian calendar. It is widely used in astronomy and software because it turns dates into a single running integer that is easy to subtract. Q: What is the difference between JD and MJD? A: The Julian Date (JD) adds the fractional day measured from noon UTC, so JD increments at midday. The Modified Julian Date (MJD) is JD minus 2,400,000.5, which shifts the day boundary to midnight and gives smaller, more convenient numbers for modern dates. Q: Does this work for historical dates? A: The calculation uses the proleptic Gregorian calendar for the input date, so it is consistent for any year you enter, but dates before the Gregorian reform of 1582 will differ from contemporary Julian-calendar records. #### Sprint Date Calculator URL: https://geratools.com/sprint-date-calculator Free agile sprint date calculator — enter a first sprint start date, sprint length and number of sprints to generate a back-to-back schedule of start and end dates. Runs entirely in your browser. How to use: 1. Set the first sprint start: Pick the date your first sprint begins. 2. Choose the cadence: Enter the sprint length in weeks and how many sprints to schedule. 3. Read the schedule: A table lists each sprint number with its start and end date, back to back. FAQ: Q: How are the end dates calculated? A: Each sprint runs for the chosen number of weeks. The end date is the last day of the sprint — that is, the start plus (length × 7 − 1) days — and the next sprint starts the following day with no gap. Q: What sprint lengths are supported? A: Any whole number of weeks from 1 to 12, and from 1 to 52 sprints, which covers the one-, two-, and three-week cadences used by most Scrum and agile teams. Q: Does it skip weekends or holidays? A: No. Sprints run as continuous calendar blocks, so a two-week sprint is exactly 14 calendar days. End dates can therefore land on weekends; adjust ceremonies separately if needed. Q: Why does a two-week sprint end 13 days after it starts? A: Because the start day itself counts as day one. A 14-day sprint occupies days 1 to 14, so the last day is 13 days after the first, and the next sprint begins on day 15. Q: What date format does it use? A: Dates are shown using your browser's locale with a weekday, day, month, and year, so the format matches your regional settings automatically. Q: Is any data sent anywhere? A: No. The schedule is generated entirely in your browser and nothing is uploaded. #### CCTV Storage Calculator URL: https://geratools.com/cctv-storage-calculator Free CCTV storage calculator. Enter cameras, resolution, codec, frame rate, recording hours and retention days to size your NVR hard drives and estimate disk cost. Runs in your browser. How to use: 1. Enter the number of cameras and the stream settings: Set how many cameras you have, then pick a resolution, codec (H.265 roughly halves H.264) and frame rate. 2. Choose the scene complexity: Pick low, medium or high motion — busier scenes compress less and use more disk. 3. Set your recording schedule and retention: Enter hours recorded per day, how many days of footage to keep, and the active-recording percentage for motion-only capture. 4. Read the total and estimate disk cost: See total storage in GB or TB, plus a drive-cost estimate once you add a price per TB and headroom. FAQ: Q: How much storage does a CCTV camera use per day? A: It depends mostly on bitrate. A 1080p H.265 camera at 15 fps recording continuously is roughly 2 Mbit/s, which is about 21 GB per day. Double the resolution or switch to H.264 and it can easily reach 40 GB or more per camera per day. This calculator works it out from your exact settings. Q: How do I calculate CCTV storage requirements? A: Storage equals bitrate times recording time times the number of cameras. The core formula is bytes = bitrate(kbit/s) x 1000 / 8 x seconds. Multiply by hours per day, retention days and camera count, then add headroom for RAID and overhead. The tool does all of this automatically. Q: Does H.265 (HEVC) really halve storage versus H.264? A: Roughly, yes. H.265 typically delivers similar image quality at about 40-50% of the bitrate of H.264, so storage and bandwidth drop by a similar amount. The calculator applies a 0.5x factor for H.265 and 1x for H.264, with MJPEG modelled at about 3x. Q: How many days of CCTV footage should I keep? A: Common retention is 30 days for homes and small businesses, though some sectors (licensed premises, banks, transport) require 31, 60 or 90 days by regulation. Storage scales linearly with retention, so doubling the days doubles the disk you need. Q: Does lowering frame rate save storage? A: Yes, but not linearly. Modern encoders compress near-static frames efficiently, so halving the frame rate saves storage but less than half. This tool uses a sub-linear model (0.4 + 0.6 x fps/15) so the estimate stays realistic rather than over-counting the saving. Q: Why add headroom to the disk size? A: Raw footage is only part of the picture. RAID parity, the recorder OS, search indexes and a margin for growth all consume space, and drives sold as 1 TB hold slightly less once formatted. A 15-20% headroom keeps your NVR from filling up and overwriting footage early. #### Printable Calendar Generator URL: https://geratools.com/printable-calendar-generator Free printable calendar generator. Build a single month or a full 12-month calendar for any year, choose your week start, add events and holidays, then export a crisp A4 PDF — all in your browser, nothing uploaded. How to use: 1. Choose month or full year: Pick single-month mode for one page, or full-year mode to fit all 12 months on one sheet. 2. Set the year and start day: Type any year and choose whether weeks start on Monday, Sunday or Saturday. 3. Add events and style it: Add birthdays, holidays or deadlines, pick an accent colour, then download the printable PDF. FAQ: Q: How do I make a printable calendar for a specific month? A: Choose single-month mode, set the year and pick the month, then adjust the week-start day and any events you want shown. The live preview updates instantly and the Download button exports that one month as an A4 PDF ready to print. Q: Can I create a full-year calendar on one page? A: Yes. Switch to full-year mode and all 12 months are laid out in a grid on a single A4 sheet — three columns by four rows in portrait, or four by three in landscape. It is ideal for a wall planner or a year-at-a-glance overview. Q: Can I choose whether the week starts on Monday or Sunday? A: Yes. The week-start selector supports Monday (the ISO and UK default), Sunday (common in the US) and Saturday (used in parts of the Middle East). Weekday headers and weekend shading all rebuild automatically when you change it. Q: Will my events and settings be saved if I close the tab? A: Yes. Your year, mode, colour, week-start choice and every event you add are stored in your browser using local storage. Re-open the page on the same device and browser and everything is exactly as you left it. Nothing is sent to any server. Q: Can I add holidays or birthdays to the calendar? A: Add as many events as you like by entering a date and a short label. In month mode the label prints inside the day cell; in year mode the day gets an accent marker so the page stays readable. Toggle events off any time without deleting them. Q: Is the calendar really generated entirely in my browser? A: Completely. Every date calculation and the PDF itself are produced locally with JavaScript and the jsPDF library. No dates, events or personal details ever leave your device, which makes it safe for private schedules and confidential planning. #### Months Between Dates Calculator URL: https://geratools.com/months-between-dates-calculator Free months between dates calculator. Instantly shows complete months, years, total days and weeks between any two dates. 100% client-side — no data leaves your browser. How to use: 1. Enter your start date: Pick the earlier date using the date picker, or type it in YYYY-MM-DD format. 2. Enter your end date: Pick the later date. The tool also accepts a future date if you want to count months ahead. 3. Read the result: The large number shows complete calendar months. Below it you will find the breakdown: years and remaining months, total days, whole weeks, and leftover days. 4. Use quick presets: Click "Last 3 mo", "Last 1 yr" etc. to fill both fields instantly for common spans. 5. Copy the result: Hit "Copy result" to put the full summary sentence on your clipboard. FAQ: Q: What counts as a complete calendar month? A: A complete month is counted only when the end date has reached or passed the same day-of-month as the start date. For example, 1 Jan to 15 Feb is 1 complete month; 1 Jan to 1 Feb is exactly 1 complete month; 1 Jan to 31 Jan is 0 complete months (the second month has not started). This matches how HR contracts, tenancy agreements, and payroll systems define "months elapsed". Q: How is the month difference calculated? A: The formula is: raw months = (endYear - startYear) * 12 + (endMonth - startMonth). If the end day is less than the start day, subtract 1 to account for the incomplete final month. Days and weeks use the raw millisecond difference divided by 86 400 000 ms. Q: Does the tool handle leap years correctly? A: Yes. Day counting uses JavaScript Date objects which account for leap years automatically. Month counting uses the calendar-month algorithm, which is not affected by leap years — only the day-of-month comparison matters. Q: Can I calculate months into the future? A: Absolutely. Enter any future date as the end date and the calculator works the same way. You can even enter the end date as the earlier date; the tool detects this and shows the absolute span with a note. Q: Why does my employment contract say a different number of months? A: Some contracts count partial months as full months (ceiling) or use a 360-day "banker year". This calculator counts only complete calendar months (floor method), which is the most common convention. If your contract uses a different rule, divide the total days shown by 30.44 (the average days per month) for an approximate fractional result. Q: Is my date data sent to a server? A: No. All computation runs in your browser using JavaScript. No dates, results, or any other information are transmitted to any server. #### Time Card Calculator URL: https://geratools.com/time-card-calculator Free weekly time card calculator. Enter clock-in, clock-out and unpaid break minutes for each day to get daily and weekly hours, plus optional gross pay with an overtime rule. Handles overnight shifts. Runs entirely in your browser. How to use: 1. Enter each day: Type the clock-in and clock-out time for every day you worked. 2. Deduct breaks: Add unpaid break minutes in the break column so they are subtracted from that day's total. 3. Add pay and overtime (optional): Enter an hourly rate, the weekly overtime threshold and the overtime multiplier to estimate gross pay. FAQ: Q: How are overnight shifts handled? A: If the clock-out time is earlier than the clock-in time, the calculator assumes the shift crossed midnight and adds 24 hours, so a shift from 22:00 to 06:00 counts as 8 hours rather than a negative value. Q: How is overtime calculated? A: Hours up to your weekly threshold (40 by default) are paid at the base rate. Any hours beyond it are paid at the base rate multiplied by your overtime multiplier (1.5 by default). Set the threshold to a very high number if you do not want any overtime split. Q: Which currency and tax does the pay figure use? A: The pay figure is gross (before tax and deductions) and is shown in whatever currency your hourly rate is in — the tool does not assume a country. It is an estimate to sanity-check a payslip, not a payroll system. ### Photo & Video #### Astrophotography Mosaic Panel Calculator URL: https://geratools.com/astrophotography-mosaic-planner Enter sensor size, focal length, target dimensions in degrees, and overlap percentage to compute your camera field of view and the number of panels and grid layout needed for an astrophoto mosaic. For imaging large nebulae. How to use: 1. Enter your camera and optics: Type your sensor width and height in millimetres and your telescope or lens focal length in millimetres. 2. Set the target and overlap: Enter the width and height of your target in degrees and the overlap percentage between adjacent panels (15 to 25 percent is typical). 3. Read the grid: The tool computes your single-frame field of view in degrees, then the number of columns, rows, and total panels needed to cover the target with overlap. FAQ: Q: How is the field of view calculated? A: Field of view in degrees equals the arctangent of the sensor dimension over twice the focal length, doubled, converted to degrees. A common approximation is 57.3 times sensor size divided by focal length, which the tool uses in its full trigonometric form for accuracy across wide fields. Q: Why do mosaics need overlap? A: Overlap gives the stacking software shared stars to register and blend adjacent panels seamlessly, and it covers vignetting and edge distortion that you crop away. Without overlap, gaps or hard seams appear between panels. Fifteen to twenty-five percent is the usual range. Q: How does overlap change the panel count? A: Each panel only contributes its effective field of view, which is the full field times one minus the overlap fraction. The tool divides the target size by that effective field and rounds up, so higher overlap means more panels to cover the same area. Q: What target size should I enter? A: Use the angular size of your subject in degrees. For example, the North America Nebula spans roughly 2 by 2 degrees, the Andromeda Galaxy about 3 by 1 degrees. Add a little margin so the target is comfortably framed rather than touching the edges. Q: Does this account for sensor orientation? A: It assumes the sensor's width maps to the target's width and its height to the target's height. If you rotate the camera, swap your sensor width and height inputs. Planning in the orientation you will actually shoot gives the correct column and row counts. #### Astrophotography Total Exposure Calculator URL: https://geratools.com/astrophotography-sub-exposure-calculator Enter sub-exposure SNR, read noise, and a target signal-to-noise ratio to compute how many sub-frames you must stack and the total integration time. Stacking adds in quadrature, so the math is not linear. For deep-sky astrophotographers. How to use: 1. Enter the SNR of one sub: Measure or estimate the signal-to-noise ratio of a single sub-frame on your target, then type it in. 2. Set your target SNR: Enter the final stacked SNR you are aiming for. A smooth, print-ready image of a faint nebula often needs an SNR of 30 to 50 or more. 3. Read subs and total time: With the sub length filled in, the tool shows how many frames you must stack and the total integration time to reach your target. FAQ: Q: Why does stacking not just add SNR linearly? A: When you average N sub-frames, the random noise falls by the square root of N while the signal stays constant. So the stacked SNR is the single-sub SNR multiplied by the square root of the number of subs, not by N itself. Q: How many subs do I need to double my SNR? A: Because SNR grows with the square root of frame count, doubling your SNR requires four times as many subs. Going from 10 to 40 frames doubles SNR; going from 40 to 160 doubles it again. This is the diminishing-returns reality of long integrations. Q: What is a good target SNR? A: It depends on the target and how much you stretch the image. Bright objects look clean at an SNR around 20, while faint outer nebulosity that you stretch hard can need an SNR of 50 or more before noise stops being visible. Q: Does read noise matter here? A: Read noise sets the SNR of a single sub for a given exposure length. Longer subs collect more signal relative to a fixed read-noise floor, raising single-sub SNR. This tool takes your measured single-sub SNR as the input, so the read-noise effect is already baked in. Q: Can I trade longer subs for fewer frames? A: Yes. A longer sub raises the SNR of each frame, so you need fewer of them. But very long subs risk losing frames to satellites, wind, or guiding errors. Many imagers pick a sub length that comfortably swamps read noise, then stack enough of them. #### Audio File Size Calculator URL: https://geratools.com/audio-file-size Calculate the size of an uncompressed PCM audio file (WAV/AIFF) from sample rate, bit depth, channel count and duration. Shows file size in MB, MiB and GB plus the bit rate, for session planning and storage budgeting. How to use: 1. Set the audio format: Choose the sample rate (44.1k to 192k), bit depth (16/24/32) and channel count for your recording. 2. Enter the duration: Type the length of the recording in minutes and seconds. 3. Read the size: The tool shows the uncompressed file size in MB, MiB and GB along with the data rate in kbps. FAQ: Q: How is uncompressed audio file size calculated? A: File size equals sample rate × (bit depth ÷ 8) × channels × duration in seconds. Each sample stores one value per channel, the bit depth sets the bytes per sample, and the sample rate sets how many samples per second. Q: Why is a 24-bit/96 kHz file so much bigger than CD quality? A: Both axes scale the size. 96 kHz is 2.18 times the 44.1 kHz sample count, and 24-bit is 1.5 times the bytes-per-sample of 16-bit, so the file is roughly 3.3 times larger for the same duration and channel count. Q: Does this apply to MP3, AAC or FLAC? A: No. Those are compressed formats. MP3 and AAC are lossy and far smaller; FLAC is lossless and typically 40-60 percent the size of WAV. This tool gives the uncompressed PCM size that WAV and AIFF store. Q: What about the WAV file header? A: A standard WAV header is about 44 bytes, which is negligible next to the audio data — even a one-second stereo CD-quality clip is over 170,000 bytes. The tool reports the audio payload size, accurate to within that header. Q: What is the difference between MB and MiB shown here? A: MB uses decimal units (1,000,000 bytes), as quoted by drive manufacturers and most cloud storage. MiB uses binary units (1,048,576 bytes), as reported by many operating systems. The tool shows both so figures match whatever tool you compare against. #### Aviation Noise Exposure Reference Tool URL: https://geratools.com/aviation-noise-exposure-reference Provides an embedded lookup of ICAO Chapter and FAA Stage noise certification levels for common aircraft types, explains the dB limits at the lateral, flyover, and approach measurement points, and shows the cumulative margin. For airport planners and noise compliance teams. How to use: 1. Select an aircraft type: Choose a common aircraft from the list to load its certified noise levels and classification. 2. Review the three measurement points: Read the EPNdB figures at the lateral, flyover, and approach points alongside the ICAO Chapter and FAA Stage classification. 3. Check the cumulative margin: The tool sums how far below the limit the aircraft is at all three points to give the cumulative margin used in modern noise rules. FAQ: Q: What is EPNdB? A: Effective Perceived Noise in decibels is the metric used to certify aircraft noise. It weights the sound for human perception and duration, including the annoyance of tonal components, so it captures how loud an aircraft actually seems rather than raw sound pressure alone. Q: What are the three measurement points? A: Lateral or sideline is measured beside the runway during takeoff at the point of maximum noise. Flyover is measured under the departure path after the aircraft has climbed. Approach is measured on the glideslope before landing. An aircraft must meet a limit at each. Q: How do ICAO Chapters relate to FAA Stages? A: They are parallel systems for the same standards. ICAO Annex 16 Chapter 3 matches FAA Stage 3, Chapter 4 matches Stage 4, and Chapter 14 matches Stage 5, which is the strictest current standard. A modern airliner is typically Chapter 14 or Stage 5. Q: What is the cumulative margin? A: It is the sum of the margins to the limit at all three measurement points. Modern rules like ICAO Chapter 4 and Chapter 14 require an aircraft to be a minimum number of cumulative EPNdB below the older Chapter 3 limits, so the cumulative margin shows compliance headroom. Q: Are these values exact for compliance work? A: No. The figures are representative levels and the limits shown are illustrative for a mid-size jet, because real ICAO Annex 16 limits scale with maximum takeoff weight. For certification or airport compliance work, always use the official type-certificate data sheet for the specific aircraft. #### Camera Angular Resolution Calculator URL: https://geratools.com/camera-resolution-angular Compute angular resolution in arcseconds per pixel from sensor pixel pitch and lens focal length, plus field of view and the lens diffraction limit. Useful for astrophotography sampling and optical inspection. Runs in your browser. How to use: 1. Enter pixel pitch and focal length: Type the sensor's pixel pitch in micrometres and the lens or telescope focal length in millimetres. 2. Add pixel count and aperture: Enter the sensor width in pixels for the field of view, and the f-number and wavelength so the tool can show the diffraction limit. 3. Read the image scale: The headline figure is arcseconds per pixel. Compare it against your seeing or the diffraction limit to see whether the system is pixel or diffraction limited. FAQ: Q: How is angular resolution per pixel calculated? A: For the small angles involved, one pixel subtends pixel pitch divided by focal length in radians. Multiplying by 206265 converts radians to arcseconds. A 3.76 micrometre pixel behind a 400 mm lens gives about 1.94 arcseconds per pixel. Q: What is a good arcseconds-per-pixel value for astrophotography? A: Aim to sample at roughly one-third to one-half of your seeing disc. With typical seeing of 2 to 4 arcseconds, an image scale of about 1 to 2 arcseconds per pixel is a common sweet spot that avoids both under and over sampling. Q: What does diffraction-limited mean here? A: If the lens's diffraction blur (the Rayleigh limit) is larger than one pixel, the optics, not the sensor, set the finest detail. The tool reports whether your system is pixel limited or diffraction limited so you know which to improve. Q: How is the diffraction limit computed? A: It uses the Rayleigh criterion: 1.22 times the wavelength divided by the aperture diameter, in radians. The aperture diameter is the focal length divided by the f-number. Green light at 550 nm is a common reference wavelength. Q: Does this work for machine-vision inspection too? A: Yes. The same image-scale maths tells you the smallest angle, and therefore the smallest feature at a known distance, that one pixel can resolve, which is the starting point for sizing an inspection camera and lens. #### Exposure Bracketing Calculator URL: https://geratools.com/exposure-bracketing-calc Build a set of bracketed exposures at plus and minus 1, 2 or 3 stops in full, half or third-stop steps around a base exposure. Outputs the exact shutter speed, aperture or ISO value for each frame, ready for HDR and focus-stacking workflows. How to use: 1. Set the base exposure: Pick which parameter you will vary (shutter, aperture or ISO) and enter the base value that gives a correct exposure for the mid-tones. 2. Choose the bracket range and step: Select how many stops to span either side and whether each step is a full, half or third stop. More frames means finer coverage of the dynamic range. 3. Read the sequence: The tool lists each frame from darkest to brightest with its EV offset and the exact value to dial in for the chosen parameter. FAQ: Q: What is exposure bracketing? A: It is shooting the same scene at several exposures, some darker and some brighter than the meter reading, so you capture detail across the full brightness range. The frames are later merged for HDR or used to pick the best single exposure. Q: How does the calculator convert stops to values? A: Each stop doubles or halves the light. For shutter and ISO the value is multiplied by two to the power of the EV offset. For aperture the f-number is multiplied by the square root of two to the power of the offset, because aperture controls light by area. Q: Which parameter should I bracket? A: For HDR landscapes vary the shutter speed so depth of field and noise stay constant. Avoid bracketing aperture because it changes depth of field between frames, and avoid bracketing ISO because it changes noise. Shutter bracketing is almost always the right choice for static scenes. Q: How many frames do I need for HDR? A: Three frames at plus and minus 2 stops covers most scenes. High-contrast scenes such as a bright window in a dark room benefit from five or seven frames spanning plus and minus 3 stops. More frames give smoother tonal transitions but require a steady tripod. Q: What step size is best? A: Full-stop steps give the widest coverage with the fewest frames and are ideal for handheld HDR. Half or third-stop steps give finer overlap for very high dynamic range or when blending shadows precisely, at the cost of more frames and more storage. #### Field of View Calculator URL: https://geratools.com/field-of-view-calculator Computes the angular field of view in degrees from focal length and sensor dimensions, plus the real-world frame coverage in metres and feet at any distance. Plans shots, video framing, and lens choice for any camera format. How to use: 1. Enter the focal length: Type the focal length of your lens in millimetres. Shorter focal lengths give a wider field of view. 2. Select your sensor format: Choose your camera's sensor from the list, or enter custom width and height in millimetres for an unusual format. 3. Read the angles and coverage: The tool shows the horizontal, vertical, and diagonal angle of view in degrees, plus the scene width and height captured at your chosen subject distance. FAQ: Q: How is field of view calculated? A: The angle of view equals two times the arctangent of the sensor dimension divided by twice the focal length. Horizontal, vertical, and diagonal angles each use the matching sensor dimension or its diagonal. Q: Why does sensor size change the field of view? A: The same lens projects the same image circle, but a larger sensor captures more of it, giving a wider field of view. A 35 mm lens is moderately wide on full frame but a short telephoto on Micro Four Thirds. Q: What is the crop factor? A: Crop factor is the ratio of a sensor's diagonal to full frame's. A smaller sensor crops the image, so multiplying focal length by the crop factor gives the full-frame-equivalent focal length for the same field of view. Q: How do I find the real-world coverage at a distance? A: The frame width equals two times the distance times the tangent of half the horizontal angle of view. The tool computes this for your chosen distance and shows both metres and feet. Q: Which angle should I use for video? A: Video and photography usually frame by the horizontal angle of view since most footage is landscape. The diagonal angle is the traditional photographic figure and is largest, while the vertical matters for tall subjects. #### Focus Peaking Contrast Threshold Guide URL: https://geratools.com/focus-peaking-contrast-threshold Get a focus peaking sensitivity recommendation — low, medium or high — based on your aperture, focal length and subject contrast, so peaking highlights mark the true focus plane instead of every busy edge. A free in-browser guide for manual-focus and video shooters. How to use: 1. Choose your aperture: Select the f-number you are shooting at. Wider apertures create a thinner focus plane that needs lower peaking sensitivity. 2. Enter focal length and subject contrast: Type your focal length and pick whether your subject and background are low, medium or high contrast. 3. Apply the recommended level: Set your camera's focus peaking to the suggested low, medium or high level and pick a peaking colour that stands out against your scene. FAQ: Q: What does focus peaking sensitivity actually change? A: Sensitivity sets the local-contrast threshold a pixel edge must exceed before the camera paints a peaking highlight on it. High sensitivity lights up faint edges and risks false positives; low sensitivity only highlights the sharpest, highest-contrast edges that are genuinely in focus. Q: Why does a wide aperture need lower sensitivity? A: A wide aperture produces a very shallow depth of field, so only a thin slice of the scene is truly sharp. High sensitivity would highlight slightly soft edges on either side of that slice, misleading you. Low sensitivity restricts the highlights to the genuinely in-focus plane. Q: My background lights up with peaking even when soft — why? A: High-contrast textures like foliage, hair or text have strong edges that can exceed the peaking threshold even when slightly out of focus. Lower the sensitivity and choose a peaking colour that contrasts the scene so you can tell true focus from false highlights. Q: What peaking colour should I use? A: Pick a colour absent from your subject. Red or yellow works well on skin, sky and low-contrast scenes; blue is better against warm or green-heavy frames. The goal is maximum visibility of the highlights without blending into the image. Q: Is focus peaking accurate enough for fast lenses wide open? A: Peaking is a guide, not a guarantee. At f/1.2 to f/1.8 the depth of field can be millimetres deep, so combine low-sensitivity peaking with magnified live view for critical focus, especially for portraits where you want the eye razor sharp. #### Long Exposure Noise & Hot Pixel Estimator URL: https://geratools.com/long-exposure-noise-estimator Estimate the thermal noise, hot pixels and fixed-pattern noise a long exposure will accumulate at a given ISO, exposure time and sensor temperature, then get a Long Exposure Noise Reduction (LENR) recommendation. A free in-browser planning tool for astrophotography and night photography. How to use: 1. Enter your exposure time: Type the planned shutter time in seconds — for example 120 for a two-minute exposure or 1800 for a 30-minute star trail. 2. Set ISO and temperature: Enter the ISO you intend to use and the ambient or sensor temperature in degrees Celsius. Sensors typically run a few degrees above ambient. 3. Read the noise band and advice: The tool returns a relative thermal-noise index, a severity band and a clear recommendation on whether to enable LENR or dark-frame subtraction. FAQ: Q: How does temperature affect long-exposure noise? A: Dark current — the thermal signal that builds up even with no light — roughly doubles for every 6 to 8 °C rise in sensor temperature. A 30 °C summer night can produce several times more hot pixels than a 5 °C winter night for the same exposure, which is why cooled astro cameras exist. Q: What is the relative thermal-noise index? A: It is a single number normalised so that a 1-second exposure at ISO 100 and 20 °C equals 1×. A reading of 10× means roughly ten times the thermal-noise standard deviation of that reference, useful for comparing scenarios rather than predicting an exact pixel value. Q: What is LENR and when should I use it? A: Long Exposure Noise Reduction takes a second, equal-length dark frame with the shutter closed immediately after your shot and subtracts its hot pixels and fixed pattern. Use it whenever the tool reports Moderate severity or higher, accepting that it doubles total capture time. Q: Does lowering ISO reduce thermal noise? A: Yes. ISO gain amplifies the accumulated dark signal linearly, so halving ISO roughly halves the thermal-noise index in this model. For very long exposures, a lower ISO combined with a longer time often produces a cleaner file than high ISO with a shorter time. Q: Why stack short exposures instead of one long one? A: Several shorter sub-exposures accumulate less dark current each, and averaging them in software reduces random noise by the square root of the number of frames. This is the standard astrophotography approach and often beats a single very long exposure for shadow cleanliness. #### ND Filter Exposure Calculator URL: https://geratools.com/nd-filter-exposure Free ND filter calculator. Enter your base shutter speed and pick an ND filter from ND2 to ND100000 to get the new required shutter speed for long exposures. Supports stacking two filters and shows the combined stop reduction. Runs entirely in your browser. How to use: 1. Enter your base shutter speed: Meter the scene without a filter and type the shutter speed as a fraction like 1/250 or in seconds like 0.5. 2. Choose your ND filter: Pick the ND filter you are using, from ND2 (1 stop) up to ND100000. Add a second filter to stack them. 3. Read the new shutter speed: The calculator multiplies your base time by 2 raised to the total stops and shows the exposure time to dial in. FAQ: Q: How do ND filter stops relate to the ND number? A: The number of stops equals the base-2 logarithm of the ND number. ND2 is 1 stop, ND4 is 2 stops, ND8 is 3 stops, and so on doubling each time, so ND1000 is about 10 stops and ND100000 is roughly 16.6 stops. Each stop doubles the required exposure time. Q: How is the new shutter speed calculated? A: New time equals the base shutter speed multiplied by 2 raised to the total number of stops. A 1/250 second base with a 10-stop ND filter becomes (1/250) × 1024 ≈ 4 seconds. This tool does the multiplication for you and formats the result. Q: Can I stack two ND filters? A: Yes. Stacking adds the stop values together, so an ND1000 at 10 stops combined with an ND8 at 3 stops gives 13 stops of total reduction. This calculator lets you select two filters and sums their stops automatically, though stacking can introduce vignetting and colour casts. Q: What ND filter do I need for silky water or cloud blur? A: Smooth water usually needs exposures of several seconds, often a 6 to 10 stop filter in daylight, while streaking clouds may need 30 seconds or more, calling for a 10 stop ND or stronger. Enter your metered base speed and try different filters to land in the second-to-minute range. Q: How do I shoot exposures longer than 30 seconds? A: Most cameras max out at a 30-second timed shutter, so for longer exposures switch to Bulb mode and time the shutter with a remote release or app. The calculator shows the exact target time in minutes so you know how long to hold the shutter open. #### Panorama Nodal Point Calculator URL: https://geratools.com/panorama-nodal-point Estimate the entrance pupil (no-parallax point) position for your lens from focal length, flange distance and lens design, then set your panorama head's rotation axis there to stitch seamless multi-row panoramas without parallax errors. A free in-browser planning tool. How to use: 1. Enter your lens specs: Type the focal length, choose the lens design type, and enter the camera's flange focal distance and the lens physical length. 2. Read the pupil position: The tool estimates the entrance pupil distance from the sensor plane, the mount flange and the front element. 3. Set and verify on the rail: Position the camera on your nodal slide so the rotation axis passes through that point, then fine-tune by aligning a near and far edge while rotating. FAQ: Q: What is the no-parallax point? A: It is the point in the lens — the entrance pupil — about which the camera must rotate so that near and distant objects do not shift relative to each other between frames. Rotating about any other point introduces parallax that makes seams impossible to stitch cleanly. Q: Is it the same as the nodal point? A: Strictly no. Photographers traditionally call it the nodal point, but the correct optical term is the entrance pupil — the apparent location of the aperture seen from the front of the lens. The rear nodal point is a different optical reference, so this tool estimates the entrance pupil. Q: Why does this need verifying empirically? A: Lens designs vary, especially zooms and retrofocus wide angles, so a formula only gives a starting offset. Pinpoint the exact point by aligning a near vertical edge with a far one through the viewfinder and sliding the camera until they stop moving against each other when you rotate. Q: Does the no-parallax point move when I zoom or focus? A: Yes. The entrance pupil position changes with focal length on a zoom and shifts slightly when focusing, so each zoom setting needs its own rail mark. Find and note the position at the focal lengths you shoot panoramas at most often. Q: Do I need a special panorama head? A: For single-row panoramas a nodal slide on a normal tripod head is enough. Multi-row panoramas and very wide lenses benefit from a dedicated panoramic head with calibrated rotation detents, but the entrance-pupil principle is identical. #### Zone System Exposure Calculator URL: https://geratools.com/photographic-zone-system Map a metered exposure to the 11-zone scale and find the stop adjustment needed to place any key tone in your target zone. Built for black-and-white film and large-format photographers using the Ansel Adams Zone System. Runs 100% in your browser. How to use: 1. Meter the key tone: Spot-meter the most important tone in your scene — usually a textured shadow you want to keep detailed. 2. Choose its target zone: Pick the zone where that tone should fall, for example Zone III for a shadow with full texture. 3. Apply the adjustment: The calculator shows how many stops to add or subtract from the meter reading to place the tone correctly. FAQ: Q: What is the Zone System? A: The Zone System is a method developed by Ansel Adams and Fred Archer for previsualising and controlling tonal values. It divides the tonal range into 11 zones, from Zone 0 (pure black) to Zone X (pure white), each one stop of exposure apart. Q: Why is Zone V special? A: Zone V is 18% middle grey — the value a reflected-light meter renders any subject as. Every meter reading effectively assumes the area is Zone V, which is why you must adjust exposure to place tones in any other zone. Q: How do I place a tone in a chosen zone? A: Subtract 5 from the target zone number to get the exposure change in stops. Placing a tone in Zone III means (3 − 5) = −2 stops, so you reduce exposure by two stops from the meter reading. Q: What does expose for the shadows mean? A: In black-and-white work you set exposure so shadow detail falls in Zone III or IV, because film loses shadow detail quickly when underexposed. Highlights are then controlled in development. This calculator handles the shadow-placement step. Q: Does this work for digital cameras? A: The placement maths is identical, but digital sensors clip highlights abruptly, so many digital shooters expose to the right and place highlights in Zone VIII–IX instead. The stop calculations here still apply. #### Astrophoto Depth of Field & Hyperfocal Distance URL: https://geratools.com/photography-depth-of-field-calculator Enter focal length, aperture and sensor format to compute hyperfocal distance, plus the near and far limits of acceptable sharpness at any focus distance. Built for landscape and Milky Way astrophotographers who need a sharp foreground and stars at infinity. How to use: 1. Enter your lens settings: Type the focal length and the aperture (f-number) you plan to shoot at. Wider focal lengths and smaller apertures both increase depth of field. 2. Pick your sensor format: Choose your camera's sensor size so the tool uses the correct circle of confusion, which defines what counts as acceptably sharp. 3. Read hyperfocal and limits: Focus at the hyperfocal distance to get everything from half that distance out to infinity sharp, or enter a subject distance to see the exact near and far limits. FAQ: Q: What is hyperfocal distance? A: It is the closest focus distance at which objects all the way to infinity stay acceptably sharp. When you focus exactly at the hyperfocal distance, the depth of field extends from half that distance out to infinity, giving the most front-to-back sharpness possible at a given focal length and aperture. Q: Why does it matter for astrophotography? A: Milky Way shots usually pair a foreground subject with stars at infinity. Focusing at the hyperfocal distance keeps both the foreground and the stars acceptably sharp in a single exposure, avoiding the need to focus-stack or sacrifice one for the other. Q: What is circle of confusion? A: It is the largest blur spot that still looks like a sharp point at normal viewing size. It scales with sensor size — about 0.029 mm on full frame, 0.019 mm on APS-C, 0.015 mm on Micro Four Thirds — and smaller sensors demand sharper focus, pushing the hyperfocal distance further out. Q: How are the near and far limits calculated? A: From the hyperfocal distance H and the focus distance s, the near limit is s(H−f)/(H+s−2f) and the far limit is s(H−f)/(H−s). When the focus distance reaches or passes the hyperfocal distance, the far limit becomes infinity. Q: Should I focus exactly at the hyperfocal distance? A: It is a great starting point, but acceptably sharp is a print standard, not pixel-level critical sharpness. For large prints or demanding work, focus slightly beyond the hyperfocal distance or stop down one more stop to give yourself a safety margin at infinity. #### Resin Exposure Time Calculator URL: https://geratools.com/resin-exposure-time Estimate normal-layer and bottom-layer UV exposure times for MSLA/LCD resin printing. Scales a baseline by layer height and LED power class, and recommends base-layer multipliers and transition layers so you can dial in a calibration test fast. How to use: 1. Choose your resin type: Pick the resin class (standard, ABS-like, water-washable, tough, flexible or dental). Each has a different baseline cure speed. 2. Set layer height and LED power: Select your slice thickness and a rough LED power class for your printer. Thicker layers and weaker LEDs both need longer exposure. 3. Read the recommended range: Start in the middle of the normal-layer range and use the base-layer time and transition layers, then run an exposure-test model to fine-tune. FAQ: Q: Why are base (bottom) layers exposed so much longer? A: The first few layers must bond firmly to the build plate so the print doesn't detach mid-job. They are typically cured 3 to 16 times longer than normal layers, which over-cures them deliberately to maximise adhesion. Q: How does layer height change exposure time? A: Thicker layers need the UV to cure deeper into the resin, so exposure scales roughly with layer height. Doubling layer height from 0.05 mm to 0.10 mm roughly doubles the required normal-layer time. Q: What are transition or fade layers? A: Transition layers gradually step the exposure down from the long base-layer time to the normal time over several layers. This prevents a sudden change that can leave a visible seam or 'elephant foot' at the base of the model. Q: Why does the tool give a range instead of one number? A: Every printer's LED power, resin batch and ambient temperature differ, so a single value would be misleading. The range brackets a sensible starting window; you confirm the exact value with a printed exposure test. Q: What happens if I over-expose or under-expose? A: Over-exposure bloats fine details, closes small holes and makes supports hard to remove. Under-exposure causes soft, warped prints, layer separation and parts that fail or stick to the FEP film. The exposure test finds the sweet spot between them. #### Photography Stop Calculator URL: https://geratools.com/stop-calculator-photography Calculate the number of full, half, and third stops of light between any two aperture, shutter speed, or ISO settings. Lists the standard stop sequence and intermediate values for accurate exposure bracketing and manual control. How to use: 1. Pick the parameter: Choose whether you are comparing aperture (f-numbers), shutter speed, or ISO. Each uses a different ratio rule but the same stop scale. 2. Enter the two values: Type the starting value and the ending value. The order decides whether the result is brighter (positive) or darker (negative). 3. Read the stops: The tool shows the exact stop difference plus the nearest full, half, and third-stop labels so you can dial it in on a manual camera. FAQ: Q: What is a stop in photography? A: A stop is a doubling or halving of the amount of light reaching the sensor. Going up one stop doubles exposure; going down one stop halves it. Aperture, shutter speed, and ISO all share this same stop scale, which is why they can be traded against each other. Q: How is the aperture stop difference calculated? A: Aperture controls light by area, so the stop difference is two times the base-2 logarithm of the f-number ratio. The formula is stops = 2 x log2(f2 / f1). For example f/2.8 to f/5.6 is a ratio of 2, which equals exactly 2 stops. Q: Why is shutter speed different from aperture? A: Shutter speed and ISO scale light linearly, so one stop is a simple doubling. The formula is stops = log2(t2 / t1) for time and log2(iso2 / iso1) for sensitivity. A move from 1/125 s to 1/30 s is roughly 2 stops brighter. Q: What are half and third stops? A: Modern cameras let you adjust exposure in fractions of a stop. A third of a stop is the finest common increment (0.333 EV), a half stop is 0.5 EV. The tool rounds your result to the nearest of these so you know exactly which click to use. Q: Does the order of the two values matter? A: Yes. The first value is the reference. If the second value lets in more light the result is positive (brighter); if it lets in less the result is negative (darker). Swapping the two flips the sign but keeps the magnitude. #### Sunny-16 Exposure Rule Calculator URL: https://geratools.com/sunny-16-exposure Extends the classic Sunny-16 rule across seven lighting conditions, from bright snow to golden hour, and computes the matching aperture and shutter at your ISO. Lists equivalent exposures so you can meter without a meter. How to use: 1. Set your ISO: Choose your film speed or sensor ISO. The Sunny-16 rule pairs each lighting condition with a shutter speed of roughly one over your ISO. 2. Pick the lighting condition: Select the scene from bright sun and snow down to overcast, open shade, and golden hour. Each condition opens the aperture by a set number of stops. 3. Read the settings: The tool shows the recommended aperture and shutter plus a list of equivalent exposures so you can pick the depth of field you want. FAQ: Q: What is the Sunny-16 rule? A: On a bright sunny day, set your aperture to f/16 and your shutter speed to the reciprocal of your ISO. At ISO 100 that is f/16 at 1/100 s, which gives a correct exposure for front-lit subjects without a meter. Q: How does the rule change for cloudy weather? A: Each step toward cloudier conditions opens the aperture one stop: slight overcast is f/11, overcast f/8, heavy overcast f/5.6, and open shade f/4. The shutter stays near one over the ISO. Q: What about snow or sand? A: Highly reflective scenes like bright snow or white sand bounce extra light, so close down one stop to f/22, often called Sunny-22. This prevents the whites from blowing out. Q: Can I swap aperture for shutter speed? A: Yes. The equivalent exposure list keeps brightness constant while trading aperture for shutter. Use a wider aperture for shallow depth of field or a faster shutter to freeze motion, adjusting the other to match. Q: Is Sunny-16 accurate enough? A: For negative film and digital with latitude it is reliably close, often within half a stop. Slide film and tricky backlight benefit from a real meter, but Sunny-16 is an excellent fallback and a great way to learn exposure. #### F-Stop Calculator URL: https://geratools.com/f-stop-calculator Free f-stop calculator — compare two apertures to see the difference in stops and how much more or less light reaches the sensor. Runs entirely in your browser. How to use: 1. Enter the starting aperture: Type the f-number you are changing from, such as 8 for f/8. 2. Enter the target aperture: Type the f-number you are changing to, such as 4 for f/4. 3. Read the stops difference: The number of stops and the change in light reaching the sensor update instantly. FAQ: Q: How are stops between two apertures calculated? A: Stops = 2 × log2(a / b), because light scales with the inverse square of the f-number. Opening from f/8 to f/4 is +2 stops and lets in four times the light. Q: What are the standard full f-stops? A: The full-stop series is f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22 and f/32 — each step halves or doubles the light. Q: Does a smaller f-number mean more or less light? A: A smaller f-number means a wider aperture and more light. f/2 lets in far more light than f/16, which is why low f-numbers are described as "fast" lenses. Q: How do I compensate one stop of aperture with shutter speed? A: Each stop of aperture equals one stop of shutter speed or ISO. If you close the aperture by one stop (half the light), double the exposure time or double the ISO to keep the same exposure. Q: Why does light change with the square of the f-number? A: The f-number is the focal length divided by the aperture diameter, so it controls the diameter of the opening. Light passing through scales with area, which is proportional to diameter squared — hence the inverse-square relationship. Q: What is a half-stop or third-stop? A: Modern cameras let you adjust aperture in 1/2 or 1/3 stop increments for finer exposure control. A third-stop changes the light by a factor of about 1.26 (2^(1/3)) rather than 2. Q: Is anything uploaded? A: No — every calculation runs locally in your browser. #### Crop Factor Calculator URL: https://geratools.com/crop-factor-calculator Free crop factor calculator: enter any sensor size (width x height in mm) and a native lens specification to get the crop factor, 35 mm equivalent focal length, equivalent aperture (depth-of-field match), and horizontal field of view. Works for full frame, APS-C, MFT, 1-inch and custom sensors. Runs entirely in your browser. How to use: 1. Pick your sensor or enter custom dimensions: Choose a preset (Full Frame, APS-C Canon, APS-C Nikon/Sony/Fuji, Micro Four Thirds, 1-inch, medium format, etc.) or type exact width and height in millimetres for any sensor you own. 2. Enter your native focal length: Type the focal length printed on your lens — for example 35, 50 or 85 mm. This is the actual physical focal length, not any equivalent figure. 3. Enter your native aperture: Type the maximum (or working) aperture of your lens — for example 1.8, 2.8 or 4. 4. Read the equivalent values: The calculator instantly shows crop factor, 35 mm equivalent focal length, equivalent aperture for matching depth of field on full frame, and horizontal field of view. 5. Open Show working for the step-by-step maths: Expand the details panel to see every formula step annotated with your exact numbers. FAQ: Q: What is a crop factor? A: Crop factor (also called focal-length multiplier) is the ratio of the full-frame 35 mm film diagonal (43.27 mm) to your sensor diagonal. A sensor with a 21.6 mm diagonal has a crop factor of roughly 2x — it crops the image circle a lens projects compared to full frame. Q: How is crop factor calculated? A: Crop factor = FF_diagonal divided by sqrt(sensor_width squared + sensor_height squared). The constant 43.27 mm is the diagonal of a standard 35 mm full-frame sensor (36 x 24 mm). Medium-format sensors are larger than full frame, so their crop factor is less than 1. Q: What does equivalent focal length mean? A: Multiplying your native focal length by the crop factor gives the full-frame focal length that produces the same horizontal field of view on the same subject from the same distance. A 25 mm lens on a 2x crop sensor frames identically to a 50 mm lens on full frame. Q: Why does equivalent aperture matter for depth of field? A: Depth of field depends on physical aperture diameter (focal length divided by f-number), not f-number alone. To match the depth of field a full-frame camera produces at f/1.8, you need your cropped sensor to shoot at f/1.8 divided by the crop factor. For a 2x crop (MFT) that is f/0.9 — which most lenses cannot achieve. This is why full frame retains a depth-of-field advantage even when exposure is equivalent. Q: Does crop factor affect exposure or ISO? A: Crop factor does not directly change exposure for a given f-number and shutter speed — those are purely about light per unit area. However, cropped sensors collect less total light (smaller area), so noise at equal ISO is generally higher than full frame. Equivalent aperture accounts for depth of field only, not noise. Q: What crop factors do APS-C and Micro Four Thirds have? A: Canon APS-C sensors measure roughly 22.2 x 14.8 mm, giving a crop factor of about 1.61x. Nikon, Sony and Fujifilm APS-C sensors are slightly larger at 23.5 x 15.6 mm, giving about 1.52x. Micro Four Thirds (17.3 x 13 mm) has a crop factor of about 2x. The 1-inch format (13.2 x 8.8 mm) sits at about 2.72x. #### Hyperfocal Distance Calculator URL: https://geratools.com/hyperfocal-distance-calculator Free hyperfocal distance calculator: enter focal length, aperture and circle of confusion to find hyperfocal distance and near limit, or solve in reverse for any variable. Full depth-of-field table included. Runs entirely in your browser — nothing is uploaded. How to use: 1. Select your camera sensor format: Choose your sensor from the preset list (full-frame, APS-C, MFT, 1-inch, medium format) — this automatically fills the circle of confusion. You can also type a custom CoC value. 2. Enter focal length and aperture: Type the lens focal length in millimetres and the f-number you plan to shoot at (e.g. 8 for f/8). The calculator updates instantly as you type. 3. Read the hyperfocal distance and near limit: Set your lens focus ring to the hyperfocal distance shown. Everything from the near limit out to infinity will be acceptably sharp in the final image. 4. Use solve-for-any-variable mode: Change the Solve for dropdown to find the focal length, aperture or CoC needed to achieve a specific hyperfocal distance — useful when planning a shot in advance. 5. Check the depth-of-field table: The table below the result shows near and far limits for a range of focus distances, helping you understand how sharpness changes as you move focus closer or further than the hyperfocal point. FAQ: Q: What is hyperfocal distance? A: The hyperfocal distance is the closest focus point at which a lens keeps everything from half that distance to infinity acceptably sharp. Focus there and you get the maximum possible depth of field for your chosen focal length and aperture combination — making it the standard technique for landscapes, architecture, and street photography. Q: What is the exact formula used? A: The calculator uses the exact form H = f squared divided by (N times c) plus f, where f is focal length in mm, N is the f-number, and c is the circle of confusion in mm. The simpler approximation H = f squared / (N times c) is accurate only when H is much larger than f; this tool always adds the trailing f term for correctness. The near limit when focused at H is exactly H divided by 2 (derived from the standard near-limit formula Dn = H·d/(H+d) evaluated at d = H). Q: What is the circle of confusion and how do I choose it? A: The circle of confusion (CoC) is the diameter of the largest blur spot that still appears sharp at a normal print or display size. It depends on sensor size and print/viewing conditions. Standard values are 0.030 mm for full-frame 35 mm, 0.019–0.020 mm for APS-C Nikon/Sony, 0.019 mm for APS-C Canon, 0.015 mm for Micro Four Thirds, 0.011 mm for 1-inch sensors, and 0.050 mm for medium-format 645. Use the preset list or type your own value. Q: Why does a wider focal length produce a shorter hyperfocal distance? A: Hyperfocal distance scales with the square of the focal length divided by the f-number and CoC. A 24 mm lens has a focal-length-squared of 576 mm squared, while a 50 mm lens has 2500 mm squared — more than four times larger. This means wide-angle lenses reach the hyperfocal point much closer to the camera, which is why ultra-wide lenses at small apertures can appear acceptably sharp from less than a metre to infinity. Q: What does the near-limit figure mean in practice? A: When you focus your lens at the hyperfocal distance, the near limit is the closest subject distance that will still appear acceptably sharp. The far limit is infinity. Everything between the near limit and infinity is within the depth of field. For a 50 mm full-frame lens at f/11, the hyperfocal distance is about 7.6 m and the near limit is about 3.8 m — so subjects closer than 3.8 m will look soft even though infinity is sharp. Q: Can I use this to reverse-engineer a lens or aperture setting? A: Yes. Use the Solve for dropdown to switch the unknown. To find what aperture you need to push the hyperfocal distance to a specific value (e.g. you want everything sharp from 5 m to infinity), enter 5 m as H, your focal length and CoC, and the calculator solves N = f squared divided by (c times (H minus f)). Similarly you can solve for focal length or CoC from a target hyperfocal distance. Q: Is any data uploaded or stored? A: No. Every calculation runs entirely in your browser using JavaScript. Nothing is ever sent to a server. There are no cookies, no analytics on your inputs, and no account required. ### Sports & Recreation #### Ballistic Zero Range Calculator URL: https://geratools.com/ballistic-zero-range-calculator Free maximum point-blank range zero calculator. Enter ballistic coefficient, muzzle velocity, and your vital zone size to find the optimal zero distance and the farthest range you can hold dead-center. For hunters and target shooters setting up rifles. How to use: 1. Enter the bullet data: Type the G1 ballistic coefficient, muzzle velocity in fps, and your scope's sight height above the bore. 2. Set the vital zone size: Enter the diameter of the target area you can hold dead-center on — about 8 inches for deer, smaller for varmints. 3. Read the optimal zero: The calculator returns the best zero distance and the maximum point-blank range over which you can aim center without holdover. FAQ: Q: What is maximum point-blank range? A: Maximum point-blank range (MPBR) is the farthest distance at which you can aim dead-center on your vital zone and still hit it, without the bullet ever rising or falling more than half the zone radius. Inside that range you simply hold center and shoot. Q: What vital zone size should I use? A: Use the kill zone of your target. A common value is 8 inches for deer-sized game, 6 inches for antelope or smaller deer, and 3 to 4 inches for varmints or precise target work. A smaller zone gives a shorter but more precise point-blank range. Q: How is the optimal zero found? A: The tool finds the launch angle whose trajectory apex just touches the top of your vital zone (half the diameter above the line of sight). The distance where the falling bullet crosses back to the line of sight is the optimal zero, and where it drops to the bottom of the zone is the MPBR. Q: Why is the optimal zero farther than I expected? A: Point-blank zeroing deliberately lets the bullet rise above the line of sight in the middle of its path so it can travel farther before dropping out the bottom of the vital zone. That is why a deer rifle is often zeroed near 200 to 260 yards rather than 100. Q: Does altitude or temperature change the result? A: Yes. The model assumes a standard sea-level atmosphere. At high altitude or in hot weather the bullet retains more velocity, slightly extending the point-blank range. Always confirm your zero with live fire under your actual conditions. #### Basketball Net Rating Calculator URL: https://geratools.com/basketball-net-rating-calculator Enter points scored and allowed plus possessions to compute Net Rating, Offensive Rating, and Defensive Rating — the core per-100-possession efficiency metrics used in NBA analysis. Runs in your browser. How to use: 1. Enter scoring totals: Type the points your team scored and the points it allowed over the stretch you want to measure. 2. Enter possessions: Type the number of possessions, or use estimated possessions from the field-goal and turnover fields if you do not have it directly. 3. Read the ratings: The tool returns Offensive Rating, Defensive Rating, and Net Rating, all expressed per 100 possessions. FAQ: Q: What is Net Rating in basketball? A: Net Rating is the difference between a team's Offensive Rating and Defensive Rating, measured per 100 possessions. A positive number means the team outscores opponents at the same pace, and it is the standard way to compare teams and lineups regardless of how fast they play. Q: What are the rating formulas? A: Offensive Rating = 100 × points scored / possessions, Defensive Rating = 100 × points allowed / possessions, and Net Rating = Offensive Rating − Defensive Rating. Scaling to 100 possessions removes pace so fast and slow teams compare fairly. Q: Why measure per 100 possessions instead of per game? A: Teams differ in pace, so per-game points reward fast teams and punish slow ones even if their efficiency is identical. Per-100-possession ratings strip out pace and isolate how well a team scores and defends on each chance. Q: How do I estimate possessions? A: A common estimate is FGA + 0.44 × FTA − offensive rebounds + turnovers. If you have the official possession count from a box score, use that directly for the most accurate ratings. Q: What is a good Net Rating? A: Championship-level teams usually post a Net Rating around +5 to +10 over a season. A rating near zero is average, and sustained negative ratings indicate a losing team. Single-game ratings are volatile and should be read with caution. #### Bowling Handicap Series Calculator URL: https://geratools.com/bowling-handicap-series-calculator Enter three game scores and your handicap to compute handicap-adjusted game scores and total series, matching the USBC league format used in team bowling competitions. Free, accurate, and runs in your browser. How to use: 1. Enter your three game scores: Type the raw (scratch) pinfall you bowled in each of the three games. Scores range from 0 to 300. 2. Set your league average and rules: Enter your current league average, the league handicap basis score, and the handicap percentage. 3. Read the handicap series: The tool computes your per-game handicap, adds it to each game, and totals the three handicap games into your series. FAQ: Q: How is a bowling handicap calculated? A: A handicap is a per-game bonus equal to the floor of (basis minus your average) times the handicap percentage. For example, a 220 basis at 90% with a 150 average gives floor of (220 minus 150) times 0.90, which is 63 pins per game. Q: What is the handicap basis score? A: The basis is the target average a league uses as the ceiling for handicapping, often 200, 210, or 220. Bowlers whose average is below the basis receive a handicap; bowlers at or above the basis get zero. Q: Why is the handicap multiplied across three games? A: A series is the sum of all games in a session. Because the handicap is added to every game, a three-game series receives the handicap three times. That is why handicap series totals are noticeably higher than scratch totals. Q: Can a handicap ever be negative? A: No. If your average meets or exceeds the basis score, your handicap is zero. The formula never produces a negative bonus, so strong bowlers simply bowl scratch. Q: Is this the official USBC method? A: It follows the standard USBC handicap structure used by most leagues. However, each league sets its own basis and percentage and may round differently, so always confirm the exact rules with your league secretary. #### Bullet Drop Ballistics Calculator URL: https://geratools.com/bullet-drop-ballistics-calculator Free G1 bullet drop and wind drift calculator. Enter ballistic coefficient, muzzle velocity, zero range, sight height, and wind to get a drop and drift table from 50 to 1000 yards. A point-mass model for precision rifle and long-range hunting. How to use: 1. Enter the bullet data: Type the G1 ballistic coefficient and muzzle velocity in fps from your ammunition box or load data, plus your scope's sight height above the bore. 2. Set zero range and wind: Enter the range you have zeroed at, the wind speed in mph, and the wind angle (90 degrees is a full crosswind). 3. Read the drop table: The tool returns bullet drop, wind drift, remaining velocity, and time of flight at standard distances out to 1000 yards. FAQ: Q: What model does this calculator use? A: It runs a point-mass numerical integration with the standard G1 drag function, stepping the trajectory forward in tiny time increments under gravity and aerodynamic drag. The launch angle is solved so the path crosses the line of sight at your chosen zero range. Q: What is the ballistic coefficient? A: The ballistic coefficient (BC) measures how well a bullet retains velocity against air resistance, referenced to a standard projectile shape. This calculator uses the G1 reference, which is printed on most factory ammunition and bullet boxes. A higher BC means less drop and drift. Q: How does wind drift work? A: Drift is computed from the crosswind component using the classic lag-time relationship: drift equals the crosswind speed multiplied by the difference between actual time of flight and the time the bullet would take in a vacuum. A 90-degree wind gives full effect; a headwind or tailwind gives none. Q: Why does my real drop differ from the table? A: The model assumes a standard sea-level atmosphere. Altitude, temperature, humidity, barrel-to-barrel velocity variation, and your specific lot of ammunition all shift the real trajectory. Always confirm your dope with live fire before relying on it in the field. Q: What sight height should I enter? A: Sight height is the vertical distance from the centre of the bore to the centre of the scope, typically 1.5 to 2.0 inches for a bolt rifle. It mainly affects the very near trajectory and where the bullet first crosses the line of sight. #### Cricket Bowling Economy Rate Calculator URL: https://geratools.com/cricket-bowling-economy-calculator Input runs conceded, overs bowled in overs.balls notation, and wickets taken to compute a bowler's economy rate, bowling average, and bowling strike rate — the three core bowling performance metrics in cricket. How to use: 1. Enter runs conceded: Type the total number of runs the bowler has conceded across their spell or career. 2. Enter overs and wickets: Add overs bowled in overs.balls notation (e.g. 8.3 means 8 overs and 3 balls) and the number of wickets taken. 3. Read the three metrics: The tool returns economy rate (runs per over), bowling average (runs per wicket), and strike rate (balls per wicket). FAQ: Q: What is a bowling economy rate? A: Economy rate is the average number of runs a bowler concedes per over. It equals total runs conceded divided by overs bowled. In limited-overs cricket an economy under 6 in ODIs or under 8 in T20 is considered good, since lower is better. Q: How do you handle part-overs like 8.3? A: Cricket overs use overs.balls notation, where 8.3 means 8 complete overs plus 3 balls, which is 51 balls in total because each over is 6 balls. The calculator converts overs to balls, computes per-ball figures, and converts back so part-overs are handled correctly. Q: What is the difference between bowling average and strike rate? A: Bowling average is runs conceded per wicket taken (runs / wickets), measuring how expensive each wicket is. Bowling strike rate is balls bowled per wicket (balls / wickets), measuring how frequently a bowler takes wickets. Lower is better for both. Q: What happens if a bowler has taken no wickets? A: With zero wickets, both bowling average and strike rate are undefined because you cannot divide by zero. The tool shows a dash for those two metrics in that case while still reporting the economy rate, which does not depend on wickets. Q: Why is economy rate so important in limited-overs cricket? A: In T20 and ODI cricket, restricting runs is often as valuable as taking wickets because every over counts toward a finite total. A bowler who concedes few runs per over applies pressure and forces batters into mistakes, so economy rate is a primary selection metric for white-ball specialists. #### Cricket Powerplay Run Rate Calculator URL: https://geratools.com/cricket-powerplay-calculator Enter runs scored, wickets lost, and overs bowled in the powerplay for T20 or ODI cricket to compute run rate and compare it against par run-rate and wicket benchmarks from recent international tournaments. How to use: 1. Choose the format: Select T20 for a 6-over powerplay or ODI for a 10-over powerplay, which sets the par benchmarks. 2. Enter runs, wickets, and overs: Type the runs scored and wickets lost, then the overs bowled using cricket notation where 5.3 means five overs and three balls. 3. Compare to par: The tool computes the run rate and shows whether the team is ahead of or behind the par run rate with an acceptable number of wickets lost. FAQ: Q: What is the powerplay in cricket? A: The powerplay is the opening phase of an innings when fielding restrictions limit how many fielders can be outside the inner ring. It lasts the first 6 overs in a T20 international and the first 10 overs in a one-day international, encouraging aggressive batting. Q: How is run rate calculated? A: Run rate is runs divided by overs, where overs are counted in decimal sixths. The tool converts cricket notation such as 5.3, meaning five overs and three balls, into 5.5 decimal overs before dividing, so the rate is mathematically correct. Q: What is a par powerplay score? A: Par reflects recent international averages. In T20 internationals a par powerplay run rate is around 8 runs per over, roughly 48 in 6 overs, while in ODIs it sits near 5.5 runs per over, roughly 55 in 10 overs. Conditions and opposition shift these figures. Q: Why do wickets matter as much as runs? A: A team can be ahead of par on runs but exposed if it has lost several top-order wickets, because the middle order then faces pressure later. The tool flags wicket loss above the benchmark, around one in a T20 powerplay, so you can judge runs and wickets together. Q: Do these benchmarks apply to every match? A: No. Par rates are averages across recent tournaments. A slow, turning pitch lowers par, a flat batting deck raises it, and a strong bowling attack suppresses scoring. Treat the comparison as a guideline rather than an absolute target. #### Cycling Nutrition & Carb Calculator URL: https://geratools.com/cycling-nutrition-calculator Enter ride duration, intensity, and bodyweight to estimate hourly carbohydrate requirement, fluid needs, and sodium loss for endurance cycling, based on current sports nutrition guidelines. How to use: 1. Set ride duration and intensity: Enter how many hours you will ride and choose an intensity level from easy endurance to hard race pace. 2. Add your bodyweight: Provide bodyweight in kilograms so fluid and sodium estimates can be scaled to your sweat rate. 3. Read your fuelling targets: The tool returns carbohydrate grams per hour, total carbs, fluid in millilitres per hour, and estimated sodium loss. FAQ: Q: How many carbs per hour should I eat on the bike? A: For rides over 90 minutes, sports scientists recommend 30-60g of carbohydrate per hour at moderate intensity and up to 90g per hour for hard, long efforts using a glucose-plus-fructose mix. This calculator scales within that range by your chosen intensity. Q: How much should I drink per hour? A: A common starting point is 500-750ml of fluid per hour, rising in heat or at high intensity. Your true need depends on sweat rate, so weigh yourself before and after a ride to refine the estimate over time. Q: Why does the tool estimate sodium? A: Sweat carries sodium, and on long or hot rides losses can cause cramps and fatigue. A typical sweat sodium concentration is around 800-1000mg per litre, so the tool multiplies estimated fluid loss by that to suggest electrolyte intake. Q: Can I exceed 60g of carbs per hour safely? A: Yes, but only with a mix of glucose and fructose, because each uses a different gut transporter. Train your gut gradually toward 80-90g per hour before relying on it in a race, and avoid this level on easy rides where it is unnecessary. Q: Does this replace a sports dietitian? A: No. These figures follow published endurance guidelines and are a solid starting point, but individual tolerance, heat acclimation, and gut training vary a lot. Use the numbers to build a plan and adjust based on real-ride experience. #### Cycling Watts Per Kilogram Calculator URL: https://geratools.com/cycling-watt-per-kg-calculator Enter FTP and bodyweight to compute watts per kilogram, then see where you sit on the TrainerRoad and Zwift category bands from Cat D (untrained) through Cat A (elite). How to use: 1. Enter your FTP: Type your functional threshold power in watts, usually taken from a 20-minute or ramp test on a power meter or smart trainer. 2. Enter your bodyweight: Add your bodyweight in kilograms (or switch to pounds). For accuracy use your race-ready riding weight. 3. Read your W/kg and category: The tool divides power by weight to give watts per kilogram and maps it onto the standard cyclist category bands. FAQ: Q: What is a good watts per kilogram figure? A: A recreational rider sits around 2.0-3.0 W/kg, a strong amateur racer is 3.5-4.5 W/kg, and elite pros sustain 5.5-6.5 W/kg at threshold. Higher W/kg means you climb and accelerate faster relative to your size. Q: Should I use 20-minute power or FTP? A: Use your FTP (functional threshold power). FTP is typically estimated as 95% of your best 20-minute average power, so apply that discount before entering the figure for an accurate threshold W/kg. Q: Why does W/kg matter more than raw watts on climbs? A: On a climb you must lift your whole body mass against gravity, so the deciding factor is power relative to weight. On flat ground aerodynamics and raw watts matter more, which is why heavier riders can still be fast on the flat. Q: How do I improve my W/kg? A: You can raise the numerator by training to increase FTP, or lower the denominator by safely reducing excess bodyweight. Most riders gain the most by combining structured threshold training with sensible body composition work. Q: Are these the same bands Zwift uses? A: The bands here mirror the widely used Zwift and TrainerRoad category guidance (A/B/C/D). Zwift racing categories can shift slightly over time, so treat the result as a close guide rather than an official ranking. #### Fishing Casting Distance Estimator URL: https://geratools.com/fishing-casting-distance-estimator Estimate maximum and comfortable casting distance from rod length, lure weight, rod action, and line type using simplified projectile mechanics with a launch-angle and air-drag model. For anglers matching rod, reel, lure, and line for longer casts. How to use: 1. Enter your rod and lure: Type the rod length in feet and the lure weight in grams or ounces, then pick the rod action that best matches your blank. 2. Choose line and conditions: Select braid or monofilament and whether you are casting into wind, with wind, or in calm air, since line diameter and wind strongly affect distance. 3. Read the distance range: The tool reports an estimated launch speed and both a maximum-effort and a comfortable repeatable casting distance in metres and yards. FAQ: Q: How accurate is this estimate? A: It is a physics-based guide, not a measured cast. Real distance depends on technique, reel quality, guide friction, and weather. Use the numbers to compare setups against each other rather than as a guarantee of how far any one cast will travel. Q: Why does lure weight matter so much? A: A rod loads and unloads best within its rated weight window. Too light and the blank cannot build energy; too heavy and the cast slows and the rod struggles to recover. The model rewards lures near the rod's sweet spot and penalises mismatches. Q: Does braid really cast further than mono? A: Generally yes. Braid of the same breaking strength is much thinner than monofilament, so it has less air drag and flows off the spool more freely. The model applies a modest distance bonus to braid to reflect this lower drag. Q: How is the launch physics modelled? A: The lure is treated as a projectile launched at roughly 45 degrees, with range proportional to launch speed squared over gravity, then scaled down by an air-drag factor that grows with line diameter and adverse wind. It is a simplified but directionally correct model. Q: How can I actually cast further? A: Match lure weight to the rod's rated window, switch to thin braid, keep guides and line clean, and improve technique with a smooth power stroke and a high release point. A longer rod also raises tip speed, which the estimator reflects. #### Fly Line Trolling Depth Calculator URL: https://geratools.com/fly-line-sink-rate-depth Enter a sinking fly line's rate in inches per second (IPS) or its sink-type rating, plus sink time and retrieve speed, to estimate how deep your fly runs. Supports Type 2 through Type 7 lines for streamer anglers. How to use: 1. Set the line's sink rate: Pick a sink-type rating (Type 2 to Type 7) to auto-fill the IPS, or enter a custom inches-per-second figure printed on your line. 2. Enter sink (countdown) time: Type how many seconds you let the line sink before retrieving. Depth grows linearly with this countdown time. 3. Adjust for retrieve speed: A faster strip lifts the fly; the tool reduces the effective depth based on your retrieve speed so the estimate matches the fishing depth. FAQ: Q: What do fly line sink types mean? A: Sink types describe how fast a line drops in inches per second. Type 2 sinks about 2 IPS, Type 3 about 3 IPS, and so on up to Type 7 at roughly 7 to 8 IPS. Higher numbers reach deeper water faster, which matters for streamers and stillwater fishing. Q: How is sink depth calculated? A: Depth before retrieving is simply sink rate times countdown time: a 4 IPS line sinking for 20 seconds reaches about 80 inches, or roughly 6.7 feet. The tool then subtracts a lift factor based on your retrieve speed, because stripping line pulls the fly upward. Q: Why does retrieve speed reduce depth? A: A sinking line keeps falling only while it sits still. Once you strip, the fly planes upward, so a fast retrieve fishes shallower than the static countdown depth. The faster you strip, the more lift, which is why a slow, deep crawl reaches the bottom and a quick retrieve stays high. Q: What is the countdown method? A: You cast, then count seconds before starting your retrieve, letting the line sink a predictable amount each second. By increasing the count until you find fish, you can repeat the exact depth that produced a strike. This calculator turns your count into a depth estimate. Q: Does line density and current change the depth? A: Yes. These figures assume still water and a fully sunk line. Current, a floating leader, and a buoyant fly all reduce real depth, while a heavy weighted fly increases it. Use the estimate as a starting point and adjust your countdown based on what you feel and catch. #### NFL Passer Rating Calculator URL: https://geratools.com/football-passer-rating-calculator Enter completions, attempts, yards, touchdowns, and interceptions to compute the official NFL passer rating using the four-component (a+b+c+d) divided by 6, times 100, over 6 formula with each component capped between 0 and 2.375. How to use: 1. Enter passing stats: Type in the quarterback's completions, pass attempts, passing yards, touchdown passes, and interceptions for the game or season. 2. Review the four components: The tool computes the four rating components (completion percentage, yards per attempt, TD rate, INT rate), each capped between 0 and 2.375. 3. Read the rating: The final passer rating appears instantly, ranging from 0 to a maximum of 158.3 (a perfect game). FAQ: Q: What is the maximum NFL passer rating? A: The maximum possible NFL passer rating is 158.3, often called a perfect passer rating. It happens when all four components hit their cap of 2.375, which requires a high completion percentage, high yards per attempt, frequent touchdowns, and zero interceptions. Q: How is the NFL passer rating formula structured? A: The formula has four components: a = (completions/attempts - 0.3) x 5, b = (yards/attempts - 3) x 0.25, c = (TDs/attempts) x 20, and d = 2.375 - (INTs/attempts x 25). Each is clamped to the 0-2.375 range. The rating equals (a + b + c + d) / 6 x 100. Q: Why are the components capped at 2.375? A: The NFL caps each component at 2.375 and floors it at 0 to keep the rating within a sensible 0-158.3 band. Without the caps, an extreme single stat (like 100% completions) could distort the rating beyond the intended scale. Q: Does passer rating include rushing or sacks? A: No. The traditional NFL passer rating only uses passing statistics: completions, attempts, yards, touchdowns, and interceptions. Rushing yards, rushing TDs, and sacks are not part of this formula. The newer Total QBR metric does factor those in. Q: What is considered a good passer rating? A: Anything above 100 is generally considered very good, and elite quarterbacks often post season ratings between 100 and 120. A rating around 90 is solid, the league average tends to sit near 85-90, and ratings below 70 indicate a struggling passing performance. #### NFL QBR (Total QBR) Estimator URL: https://geratools.com/football-qbr-calculator Input passing yards, touchdowns, interceptions, and sacks plus rushing production to estimate an ESPN Total QBR style 0 to 100 score, a more complete quarterback rating than the legacy passer rating formula. Runs free in your browser. How to use: 1. Enter the passing line: Type pass attempts, passing yards, touchdowns, interceptions, and sacks taken from the box score. 2. Add rushing production: Enter rush attempts, rushing yards, and rushing touchdowns, since QBR rewards quarterback running. 3. Read the estimated QBR: The tool builds an expected-points value per play and maps it to a 0 to 100 QBR-style scale with a performance tier. FAQ: Q: What is Total QBR and how does it differ from passer rating? A: Total QBR is ESPN's 0 to 100 metric built on expected points added per play, including rushing, sacks, and game situation. The legacy passer rating only uses completions, yards, touchdowns, and interceptions, so it ignores a quarterback's legs and the cost of taking sacks. Q: Is this the exact ESPN QBR number? A: No. ESPN's formula is proprietary and adds opponent strength, down and distance, and clutch weighting that a box score cannot reconstruct. This is a transparent estimator that approximates the scale, useful for comparing performances rather than matching the official figure. Q: How does the estimator turn stats into a QBR? A: It assigns expected-points weights to each event, roughly plus 0.8 per touchdown, minus 2 per interception, minus 1.2 per sack, and small per-yard values, then divides by total plays and maps that EPA per play onto a 0 to 100 scale centered at 50 for league average. Q: What QBR counts as a good game? A: On the 0 to 100 scale, 50 is roughly league average, the mid 60s is very good, and 75 or higher reflects elite, MVP-level play. Anything below 40 signals a poor outing where the quarterback cost the team expected points. Q: Why are sacks and rushing included? A: Sacks are negative plays the quarterback often controls, so they lower the value. Designed and scramble runs add real expected points. Including both is exactly why QBR is considered more complete than passer rating. #### Golf Club Distance & Loft Reference URL: https://geratools.com/golf-distance-club-selector Enter your driver swing speed or typical 7-iron carry distance and the tool builds a full 14-club carry matrix, scaling Tour Average gapping to fit your numbers so you know the right club for any yardage. How to use: 1. Pick a reference: Choose whether you know your driver swing speed in mph or your typical 7-iron carry distance, then enter the value. 2. Generate the matrix: The tool scales the Tour Average gapping table to your reference so every club lands at a realistic carry for your game. 3. Find your club: Read down the table to match a target yardage to the club that carries closest to it. FAQ: Q: How does the tool estimate each club's distance? A: It starts from a Tour Average gapping table where each club's carry is a known ratio of the 7-iron carry. It then scales that whole table by your reference number, either your measured 7-iron carry or a carry derived from your swing speed, so the gaps stay realistic while the absolute distances match you. Q: How is swing speed converted to distance? A: Driver carry is estimated at roughly 2.3 yards per mph of clubhead speed, a widely used rule from launch-monitor data. The tool then derives a 7-iron baseline from that driver carry and builds the rest of the bag from the gapping ratios. Q: Are these carry or total distances? A: The numbers are carry distances — how far the ball flies before landing. Total distance adds roll, which varies with turf firmness, so carry is the more reliable planning figure, especially for approach shots into greens. Q: Why do the gaps shrink toward the wedges? A: Lofts change in larger steps in the long irons and smaller steps in the wedges, and ball speed falls as loft rises. The result is wider yardage gaps at the top of the bag and tighter, more controllable gaps in the scoring clubs. Q: Should I trust this over my own gapping? A: Use it as a starting template, not gospel. Real launch-monitor data for your own swing always wins, because spin, attack angle, and strike quality shift the gaps. This table gives a sensible baseline when you do not have those numbers. #### Golf Wind Adjustment Calculator URL: https://geratools.com/golf-wind-adjustment-calculator Enter wind speed, its direction relative to your shot, and your baseline carry distance to get the adjusted playing yardage using the standard one-club-per-10-mph headwind rule, plus crosswind aim offset. How to use: 1. Enter the shot: Type your baseline carry distance for the club you would normally hit in calm conditions. 2. Enter the wind: Type the wind speed and choose its direction relative to your shot — into, behind, or across. 3. Read the playing yardage: The tool returns the effective distance the shot now plays plus, for crosswinds, how many yards to aim off line. FAQ: Q: What is the wind adjustment rule? A: A common rule is that a headwind adds roughly 1 percent of your carry distance per mph of wind, and a tailwind helps about half as much, near 0.5 percent per mph. So a 10 mph headwind makes a 150-yard shot play about 165 yards, while a 10 mph tailwind makes it play about 142. Q: Why does headwind hurt more than tailwind helps? A: A headwind increases the apparent air speed over the ball, raising lift and drag so the ball climbs and stalls, losing distance fast. A tailwind reduces spin-driven lift and the ball flies flatter, so the gain is real but smaller than the headwind loss for the same wind speed. Q: How does crosswind affect the shot? A: Crosswind mostly pushes the ball sideways rather than changing carry much. The tool estimates a sideways drift of roughly 0.75 yards per mph of crosswind over a typical iron flight, so you aim that many yards into the wind to let it bring the ball back to target. Q: Should I trust these numbers exactly? A: Treat them as a guide, not a guarantee. Ball flight, spin, launch angle, and gusts all change the real effect, and a high, spinny shot is hurt by wind far more than a low, flighted one. Use the figure to pick the club, then commit to a confident swing. Q: Do these rules work in km/h? A: Yes — switch the unit and the tool converts internally. The percentage relationship is the same; it just scales the wind speed before applying the same headwind, tailwind, and crosswind factors. #### MMA Fighter Statistical Comparison URL: https://geratools.com/mma-fighter-stats-calculator Input striking accuracy, takedown defence, submission attempts, and significant strikes per minute for two fighters to generate a head-to-head statistical advantage matrix with a weighted overall edge. How to use: 1. Enter Fighter A's stats: Fill in striking accuracy, takedown defence, submission attempts per 15 minutes, and significant strikes landed per minute. 2. Enter Fighter B's stats: Provide the same four metrics for the second fighter so they can be compared on a like-for-like basis. 3. Read the advantage matrix: The tool shows which fighter leads in each category and a weighted overall statistical edge. FAQ: Q: What stats does this comparison use? A: It uses four common UFC-style metrics: striking accuracy as a percentage, takedown defence as a percentage, submission attempts per fifteen minutes, and significant strikes landed per minute. These mirror the categories tracked on official fight statistics pages. Q: How is the overall edge calculated? A: Each metric is normalised to a comparable scale, then the two fighters' values are weighted equally and summed. The fighter with the higher weighted total is shown as holding the overall statistical edge, along with the margin. Q: What is significant strikes per minute? A: Significant strikes landed per minute, often abbreviated SLpM, counts meaningful strikes a fighter lands each minute of fight time. A figure above four is considered high-volume striking in most weight classes. Q: Does a statistical edge predict the winner? A: Not reliably. Statistics describe past performance and matchups are decided by styles, game plans, weight cut, and chance. Use the comparison as context, not a prediction. Q: What is good takedown defence? A: Takedown defence above 70 percent is solid and above 85 percent is elite. It measures the share of opponents' takedown attempts a fighter stuffs, which heavily shapes whether a bout stays standing. #### RC Aircraft Wing Loading Calculator URL: https://geratools.com/rc-aircraft-wing-loading Enter wingspan, average wing chord, and all-up weight to compute wing area and wing loading in oz per square foot and g per square decimetre. Shows a handling character from floaty trainer to hot sport jet for RC fixed-wing pilots. How to use: 1. Enter the wing geometry: Type the wingspan and the average chord (the front-to-back width of the wing). For a tapered wing, use the mean of the root and tip chord. 2. Enter the all-up weight: Enter the ready-to-fly weight including battery, fuel, and all electronics. This is what the wing actually has to lift. 3. Read the loading and character: The tool shows wing area, wing loading in two unit systems, the cubic wing loading index, and a plain-language handling description. FAQ: Q: What is wing loading? A: Wing loading is the aircraft's weight divided by its wing area. It tells you how hard the wing is working. Low wing loading means the plane flies slowly and gently; high wing loading means it must fly fast to stay airborne and lands hot. Q: What wing loading suits a beginner? A: Trainers typically sit around 10 to 16 oz per square foot, which gives forgiving low-speed handling and gentle stalls. Sport and aerobatic models run 16 to 25, and high-speed jets or pylon racers can exceed 30 oz per square foot. Q: What is cubic wing loading and why does it matter? A: Cubic wing loading divides weight by wing area raised to the power 1.5, which removes the effect of model size. It lets you compare a giant-scale model to a park flyer fairly. Values under 9 fly like a floater, over 13 like a fast sport model. Q: How is the stall-speed estimate derived? A: Stall speed scales with the square root of wing loading. The tool uses a representative lift coefficient for a typical RC airfoil to turn wing loading into an approximate stall speed in miles per hour. Treat it as a relative guide, not a precise figure. Q: Why use average chord for a tapered wing? A: Wing area equals span times mean chord. For a straight-tapered wing the mean chord is simply the average of the root and tip chords, so entering that average gives the correct area. For complex planforms, measure the actual area instead. #### Shotgun Shot String & Pattern Calculator URL: https://geratools.com/shot-string-pattern-calculator Enter choke, shot size, and payload weight to calculate the expected pattern percentage and pellet count inside a 30-inch circle at various distances. For wing shooters and clay target shooters tuning their loads. How to use: 1. Pick shot size and payload: Choose the lead shot size from the dropdown and enter the payload weight in ounces, which is printed on the shotshell box. 2. Set choke and distance: Select your choke constriction, then enter the distance to the target in yards. 3. Read pattern density: The tool shows total pellets in the shell, the percentage expected inside a 30-inch circle for that choke, and how many pellets that puts on the target. FAQ: Q: How is the total pellet count calculated? A: Each lead shot size has a known number of pellets per ounce — for example, US #8 is about 410 pellets per ounce and #6 about 225. The tool multiplies pellets per ounce by your payload weight in ounces to get the total in the shell. Q: What does the choke percentage mean? A: Choke is rated by the percentage of the total pellets that land inside a 30-inch circle at 40 yards. Full choke is about 70 percent, modified 60 percent, improved cylinder 50 percent, and cylinder 40 percent. Tighter chokes concentrate more pellets but shrink the effective spread. Q: Why does pattern percentage fall off with distance? A: The shot column spreads as it travels, so a fixed 30-inch circle captures a shrinking fraction of pellets the farther out you measure. The tool scales the choke's 40-yard rating up or down with distance to estimate the percentage at your range. Q: How many pellets do I need for a clean kill? A: A common guideline is at least 3 to 5 pellet strikes on a game bird's vital area, which usually means keeping pattern density above roughly 100 to 130 pellets in the 30-inch circle for the target species. Use the count to judge your maximum effective range. Q: Does this account for shot string length? A: The pellet count and pattern percentage are based on the standard 30-inch frontal pattern. True shot string is the lengthwise spread that affects crossing targets; this tool focuses on density, which is the dominant factor for choosing a load and choke. #### Soccer Expected Points from xG Calculator URL: https://geratools.com/soccer-expected-points-calculator Enter home xG and away xG to compute each team's expected points from the match using a Poisson distribution model, including win, draw, and loss probabilities and the most likely scoreline. Standard football analytics, free in your browser. How to use: 1. Enter home expected goals: Type the home team's total xG for the match, the sum of the quality of all its chances. 2. Enter away expected goals: Type the away team's total xG the same way. 3. Read expected points: The tool returns win, draw, and loss probabilities and converts them into expected points for each side, plus the most likely scoreline. FAQ: Q: What are expected points (xPts)? A: Expected points convert a team's chance quality into the points it deserved from a match. Using win and draw probabilities, xPts equals three times the win chance plus one times the draw chance. Over a season, xPts often predicts the table better than actual points. Q: How does the Poisson model work here? A: Each team's goals are modelled as an independent Poisson variable whose mean is its xG. The tool multiplies the two distributions across every plausible scoreline, then sums the cells where the home team wins, draws, or loses to get outcome probabilities. Q: Why use xPts instead of the actual result? A: A single match is noisy: a team can dominate, rack up high xG, and still lose to one lucky goal. xPts smooths out that variance by rewarding the performance rather than the bounce, which is why analysts track it across a season. Q: Does the model assume the teams are independent? A: Yes. It treats each team's goal count as independent Poisson, the standard simplifying assumption in football analytics. Real matches have small correlations, such as game state effects, but the independent Poisson model is accurate enough for expected points. Q: What xG values are realistic? A: Most teams record between about 0.5 and 2.5 xG in a match. Totals above 3 are rare and usually come from one-sided games. The calculator accepts any value from zero up to 15 to cover edge cases. #### Soccer Offside Line Visual Aid URL: https://geratools.com/soccer-offside-line-calculator Enter the positions of the second-last defender, the attacker, and the ball to determine whether the attacker was in an offside position at the moment of the pass, with a visual line diagram and the reasoning behind the verdict. How to use: 1. Position the attacker: Enter the attacker's distance in metres from the opponents' goal line, where a smaller number means more advanced toward goal. 2. Position the defender and ball: Enter the second-last defender's position and the ball's position at the exact moment the pass is played. 3. Read the verdict: The tool draws a line for each and reports whether the attacker was in an offside position, with the reasoning. FAQ: Q: What is an offside position under Law 11? A: An attacker is in an offside position if, at the moment a teammate plays the ball, they are nearer to the opponents' goal line than both the ball and the second-last opponent. The second-last opponent is usually the last defender because the goalkeeper is normally the very last player. Q: Is being in an offside position always a foul? A: No. Being in an offside position is only an offence if the player then becomes involved in active play, such as receiving the ball, interfering with an opponent, or gaining an advantage. A player standing offside who never touches the ball is not penalised. Q: Does level count as offside? A: No. A player who is exactly level with the second-last defender or level with the ball is considered onside. Offside requires the attacker to be strictly nearer the goal line than both reference points, which is why VAR margins are drawn so tightly. Q: Can you be offside in your own half? A: No. A player in their own half of the pitch can never be in an offside position, regardless of where the defenders are. The halfway line is a hard boundary for the offside rule. Q: Why does the moment of the pass matter so much? A: Offside is judged at the instant the ball is played by the teammate, not when it is received. An attacker can start onside, time a run, and legally end up well behind the defence, which is why the freeze-frame moment is everything in close calls. #### Soccer League Points Projection URL: https://geratools.com/soccer-points-projection Enter games played, wins, draws, and losses plus remaining fixtures to project a team's final league points using their current points-per-game rate applied across the rest of the season. How to use: 1. Enter results so far: Type in the number of games played and the breakdown of wins, draws, and losses to date. 2. Add remaining fixtures: Enter how many matches the team still has to play this season. 3. Read the projection: The tool calculates current points, points-per-game, and projects the final total assuming current form continues across the remaining fixtures. FAQ: Q: How are league points calculated in soccer? A: In almost all modern soccer leagues a win is worth 3 points, a draw 1 point, and a loss 0 points. Current points are simply wins times 3 plus draws times 1. This 3-1-0 system has been standard across most leagues since the 1990s. Q: What is points-per-game (PPG) and why use it? A: Points-per-game is total points divided by games played. It measures a team's average return per match regardless of how many games they have played, which makes it the cleanest basis for projecting how many points they will finish with. Q: How does the projection work? A: The tool multiplies the team's current points-per-game by the number of remaining fixtures to estimate future points, then adds that to current points. It assumes the team maintains its current form, so it is a baseline expectation rather than a guaranteed result. Q: Why might the projection be wrong? A: Form fluctuates, fixture difficulty varies, injuries occur, and motivation shifts late in a season. A straight PPG projection ignores all of that, so treat it as a neutral expectation. Teams chasing a title or fighting relegation often over- or under-perform their PPG baseline. Q: Can I check the consistency of my inputs? A: Yes. The tool verifies that wins plus draws plus losses equals games played and flags a mismatch. It also confirms remaining fixtures is non-negative, so you can be confident the projection is built on a coherent record. #### Soccer Expected Goals (xG) Calculator URL: https://geratools.com/soccer-xg-calculator Input shot distance from goal, angle to the posts, body part, and whether it was assisted to estimate expected goals (xG) using a logistic-regression model in the style of public Opta and StatsBomb shot data. How to use: 1. Enter the shot location: Provide the distance in metres from the centre of the goal and the horizontal offset from the goal line's centre. 2. Set shot context: Choose the body part (foot or header), whether it was a one-touch shot, and the assist type such as a cross or through ball. 3. Read the xG value: The model returns a probability between 0 and 1 representing how likely an average player is to score from that exact situation. FAQ: Q: What is expected goals (xG)? A: Expected goals (xG) is a metric that assigns each shot a probability of scoring between 0 and 1, based on historical data from similar shots. A shot worth 0.3 xG means an average player would score it roughly 30 percent of the time from that position and situation. Q: How is xG actually calculated? A: Professional xG models use logistic regression or gradient boosting trained on hundreds of thousands of shots, with features like distance, angle, body part, and assist type. This calculator uses a simplified logistic model that captures the dominant effects of distance and angle. Q: Why does shot angle matter so much? A: Angle determines how much of the goal a player can actually aim at. A shot from directly in front sees the full width of the goal, while a shot from a tight angle near the byline sees only a sliver, so even close-range chances from tight angles have low xG. Q: Are headers worth less xG than shots with the feet? A: Generally yes. Headers are harder to direct and generate less power, so from the same location a header typically carries lower xG than a foot shot. This model applies a downward adjustment for headers to reflect that. Q: Is this an exact replica of Opta or StatsBomb xG? A: No. Commercial models use proprietary data and many more features, including goalkeeper position and defender pressure. This tool is an educational approximation that reproduces the well-known distance and angle relationships, so treat its output as an estimate rather than an official figure. #### Tennis UTR & NTRP Level Guide URL: https://geratools.com/tennis-rating-level-guide Answer questions about your stroke consistency, competitive results, and game style to get an estimated NTRP level and a matching UTR range, each with a description of what that level of player can do on court. How to use: 1. Describe your game: Answer the questions about rally consistency, depth and spin control, serve reliability, and the level of player you compete with evenly. 2. Generate your estimate: The tool scores your answers and maps them to an NTRP band and an approximate UTR range. 3. Read the description: Each result includes a description of what that level plays like so you can sanity-check the estimate against your experience. FAQ: Q: What is the difference between NTRP and UTR? A: NTRP is the USTA's banded system from 1.0 to 7.0 in half-point steps, based on overall skill. UTR is a continuous 1 to 16.5 rating computed from actual match results and the closeness of scores. NTRP describes ability while UTR measures demonstrated results, so they correlate but are not identical. Q: How accurate is a self-rating? A: Self-ratings are a rough guide only. Real NTRP ratings come from computer analysis of match results and UTR is calculated purely from logged matches, so a questionnaire can be off by half a level. Use this as a starting point, then confirm by playing rated matches. Q: How do NTRP and UTR roughly line up? A: As a rough map, NTRP 3.0 ≈ UTR 1–2, 3.5 ≈ UTR 3–4, 4.0 ≈ UTR 5–6, 4.5 ≈ UTR 7–8, 5.0 ≈ UTR 9–10, and 5.5+ ≈ UTR 11+. The bands overlap and depend on gender and competition, so treat the mapping as approximate. Q: What separates a 3.5 from a 4.0 player? A: A 3.5 player has dependable strokes with directional control but loses depth and consistency under pressure. A 4.0 player has reliable depth on both wings, can vary spin and pace, serves with intent, and constructs points rather than just keeping the ball in play. Q: Does fitness or match play change my rating? A: Yes. Stamina, footwork, and recent competitive play strongly affect your effective level. A player with sound strokes but no match sharpness often rates lower in real matches than their practice level suggests, which is why logged-match systems like UTR exist. #### Golf Handicap Calculator URL: https://geratools.com/golf-handicap-calculator Free golf handicap index calculator. Enter your adjusted gross score, course rating and slope for each round and get the exact WHS Handicap Index. Runs entirely in your browser — no data is uploaded. How to use: 1. Enter your adjusted gross score: Type the total strokes for the round after applying the WHS net-double-bogey cap on each hole. 2. Add course rating and slope: Both figures appear on the scorecard or club website. Course rating is a decimal (e.g. 71.4); slope is an integer 55–155 (standard = 113). 3. Add more rounds: Click "+ Add round" to enter up to 20 rounds. The tool picks the best differentials and highlights them in green. 4. Read your Handicap Index: The Handicap Index and full calculation working are shown automatically once you have at least 3 valid rounds entered. FAQ: Q: How is a score differential calculated? A: Score Differential = (Adjusted Gross Score − Course Rating) × (113 / Slope Rating). The constant 113 is the slope of a course of standard difficulty; dividing by your course slope and multiplying by 113 normalises every round to that baseline before you average them. Q: What does the 0.96 factor do? A: The World Handicap System multiplies the average of your best differentials by 0.96 before issuing a Handicap Index. This softening factor prevents players from posting very low differentials during exceptional form and then playing off an artificially low index. It is built into every official WHS calculation. Q: How many differentials count toward my index? A: Under WHS the count depends on how many acceptable scores you have submitted. With 3 rounds only the single lowest differential is used; with 6 rounds the best 2; rising to the best 8 of your most recent 20. The table is built into this calculator automatically. Q: What is an adjusted gross score? A: It is your hole-by-hole total after capping each hole at net-double-bogey (par plus 2 plus any handicap strokes you receive on that hole). This limits the damage from a single disaster hole so your handicap better reflects your typical performance. Q: What is the difference between course rating and slope rating? A: Course rating is the expected score (in strokes, to one decimal place) for a scratch golfer playing from a specific set of tees. Slope rating measures how much harder the course plays for a bogey golfer versus a scratch golfer — standard is 113, easy courses go lower, hard ones higher, maximum 155. Q: What is the WHS maximum Handicap Index? A: The WHS caps the Handicap Index at 54.0 for all players regardless of gender. Before the WHS unified the system in 2020, national systems had different caps (e.g. 28 for men, 36 for women under the old EGA system in Europe). Q: Is my scoring data stored or uploaded anywhere? A: No. Every calculation runs entirely in your browser using JavaScript. Nothing is sent to any server and nothing is stored between sessions. #### Race Time Predictor URL: https://geratools.com/race-time-predictor Free race time predictor using the Riegel and Daniels VDOT models. Enter any race distance and finish time to see predicted times for 5K, 10K, half marathon, marathon and 18 other distances — plus training pace zones. 100% browser-based. How to use: 1. Choose your known race distance: Select 5K, 10K, half marathon or marathon from the preset buttons, or type any distance in km. 2. Enter your finish time: Type your hours, minutes and seconds in the three fields. Your pace per km and VDOT appear instantly. 3. Adjust the Riegel exponent if needed: The default exponent of 1.06 suits most trained endurance runners. Move the slider left for speed-work specialists, right for ultra runners who fade more at long distances. 4. Toggle altitude and heat corrections: Add your race elevation and expected temperature for a course-adjusted prediction. Flat, cool-weather times are always faster than a mountainous summer race. 5. Compare Riegel vs Daniels predictions: Switch between the three result tabs to see side-by-side predictions, VDOT-derived times, or your personalised training pace zones. FAQ: Q: What formula does the race time predictor use? A: It uses two independent models. The Riegel (1981) formula is T2 = T1 x (D2/D1)^1.06, where T1 is your known time, D1 the known distance, D2 the target distance and 1.06 is the empirical fatigue exponent. The Daniels VDOT model derives your aerobic fitness index from the race and inverts the VO2/velocity relationship to predict each other distance. Q: Which model is more accurate — Riegel or Daniels? A: Neither is universally better. Riegel tends to be more accurate for mid-distance comparisons (e.g. 5K to half marathon) and is easy to understand. The Daniels VDOT model captures physiology more directly and is especially useful for producing training zones alongside the predictions. Comparing both gives a confidence interval: if they agree closely, the prediction is more reliable. Q: What is a good Riegel exponent for my running profile? A: The classic Riegel value of 1.06 fits well-trained runners who balance speed and endurance. Runners who specialise in shorter distances or have more fast-twitch muscle tend to fade more at long distances — try 1.08 to 1.10. Ultramarathon runners who are very efficient at slow sustained effort may fit closer to 1.03 to 1.05. Q: Why do the Riegel and Daniels predictions sometimes differ by several minutes? A: Riegel is a purely empirical power law — it says nothing about physiology. Daniels is grounded in VO2max and assumes your aerobic capacity stays constant across distances, which breaks down at very short sprints (400 m) and very long ultras (100 km). The gap also widens if your training is highly specialised for one distance. Q: How do altitude and heat affect predicted race times? A: The calculator applies +2% per 1000 m of elevation gain (based on IAAF altitude guidelines) and +0.3% per degree Celsius above 15 C (based on ACSM heat-stress guidance). A race at 2000 m altitude on a 25 C day carries roughly a 7% combined penalty — about 13 minutes on a 3-hour marathon. Q: Can I use a 5K time to predict a marathon finish? A: Yes, but with wider uncertainty. The further apart the two distances are, the more training specificity matters. A well-trained marathoner will typically beat the Riegel prediction from a 5K by several minutes, while an untrained runner who only does parkruns may fall short. Use the prediction as a starting target and stress-test it with a half marathon tune-up race first. #### Run/Walk Interval Calculator URL: https://geratools.com/run-walk-interval-calculator Free run/walk interval calculator. Enter your run and walk segment lengths, your paces, and a session duration or target distance — see effective pace, total distance, interval count and a full split table. Runs entirely in your browser, nothing is uploaded. How to use: 1. Choose a preset or enter custom intervals: Select a preset like "Galloway 2 min/1 min" or type your own run and walk segment lengths in minutes and seconds. 2. Set your run and walk paces: Enter your running pace and walking pace in minutes and seconds per kilometre or mile. A typical walk pace is 12-15 min/km; a jog might be 6-8 min/km. 3. Enter your session goal: Pick "session duration" if you know how long you want to train, or "target distance" if you have a specific race or route in mind. 4. Read your results: The calculator instantly shows the number of full intervals, your effective overall pace, total distance covered, average speed, and a run/walk time split bar. Copy the full breakdown to your clipboard. FAQ: Q: What is the run/walk method? A: The run/walk method, popularised by Olympic marathon coach Jeff Galloway, alternates short running bursts with brief walking breaks throughout a session. The walking recovery lowers your average heart rate, delays fatigue, and — counter-intuitively — can produce a faster overall finish time than running the whole distance at a slower pace. It is widely used by beginners, injury-prone runners, and marathon participants aiming to finish strong. Q: How is the effective pace calculated? A: The effective pace is total session time divided by total distance. Total distance = (run segment seconds / run pace in sec per unit) + (walk segment seconds / walk pace in sec per unit), summed across all intervals. So if you run 1 min at 6 min/km and walk 1 min at 12 min/km, one interval covers 0.1667 + 0.0833 = 0.25 km in 2 min, giving an effective pace of 8 min/km — slower than your run pace but faster than a steady jog at that heart rate. Q: What run/walk ratio should I start with? A: Beginners typically start with equal run and walk segments — 30 sec/30 sec or 1 min/1 min. As your aerobic base improves you extend the run phase while keeping the walk break constant (2 min/1 min, then 3 min/1 min, etc.). The Couch-to-5K programme starts at 60 sec run/90 sec walk and reaches continuous running over nine weeks. This calculator lets you compare any ratio side by side. Q: Does walking really make a race faster? A: Yes, for many recreational runners. Walking one minute per mile (roughly 37 sec per km) during a marathon can lower finishing time by 7-13 minutes compared to running until forced to slow. The mechanism is glycogen conservation and reduced muscle damage. Elite runners do not need it because their aerobic economy is efficient enough, but for anyone over 4 hours in a marathon the evidence strongly favours planned walk breaks. Q: How do I find my walking pace? A: Walk a measured kilometre or mile at your comfortable training pace and time it. Most recreational walkers cover one kilometre in 10-14 minutes (6-9 mph). A purposeful power walk is 8-10 min/km. If you are mixing with running, err on the slower side (12-15 min/km) since you will be fatigued. Enter that figure in the walk pace field and the calculator accounts for it precisely. Q: Can I use this for race-day strategy? A: Absolutely. Enter your target race distance, your expected run and walk paces (be honest — race pace is usually 10-20 sec/km slower than training pace), and your planned interval ratio. The calculator shows your projected finish time and effective pace. Try several ratios to find the one that meets your goal time. A common marathon strategy is 10 min run / 1 min walk, which this calculator can model instantly. ### Clinical Scores & Lab #### Anaesthetic Gas Flow Rate Calculator URL: https://geratools.com/anesthesia-gas-flow-rate Converts vaporiser dial setting, fresh gas flow, and agent identity into delivered concentration in vol%, MAC multiples, vapour output, and liquid agent consumed per hour for sevoflurane, isoflurane, desflurane, and halothane. Runs in your browser. How to use: 1. Choose the agent: Select the volatile agent so the right liquid-to-vapour expansion ratio and 1-MAC value are applied. 2. Set flow and dial: Enter the fresh gas flow in litres per minute and the vaporiser dial setting as a volume percent. 3. Read consumption and MAC: The tool reports vapour output, liquid agent used per hour, the delivered concentration, and the equivalent MAC. FAQ: Q: How is liquid agent consumption calculated? A: The vaporiser adds vapour equal to the fresh gas flow times the dial percentage. Each millilitre of liquid agent expands into a fixed volume of vapour at room temperature, about 183 mL for sevoflurane and 195 for isoflurane, so dividing vapour output by that expansion gives the liquid used per hour. Q: Why does fresh gas flow matter so much for cost? A: For a calibrated vaporiser the delivered concentration equals the dial setting regardless of flow, but the amount of agent carried away in the fresh gas scales directly with flow. Running 4 L/min uses twice the agent of 2 L/min at the same dial, which is the whole economic case for low-flow anaesthesia. Q: What is MAC and how is it shown here? A: MAC, the minimum alveolar concentration, is the agent concentration at which half of patients do not move to a surgical stimulus. The tool divides your delivered vol% by the standard 1-MAC value for the agent to express depth as a MAC multiple. Q: Does this account for nitrous oxide or patient age? A: No. The MAC figure here uses a standard 40-year-old breathing oxygen only. Nitrous oxide is additive and MAC falls with age, so use a dedicated MAC adjustment tool when those factors apply. Q: Is delivered concentration the same as end-tidal? A: Not exactly. The dial sets the inspired concentration leaving the vaporiser, but uptake by the patient and the breathing circuit means end-tidal concentration lags behind, especially early in a case and at low flows. Always titrate to the measured end-tidal value on your monitor. #### Calcium–Phosphorus Product Calculator URL: https://geratools.com/calcium-phosphorus-product Multiply serum calcium and phosphate, with unit-aware mg/dL or mmol/L conversion, to yield the Ca x P product and flag elevated vascular calcification risk above 55 mg2/dL2 in CKD. Used in nephrology. Runs in your browser. How to use: 1. Enter serum calcium: Type the patient's serum calcium and choose whether the value is in mg/dL or mmol/L. 2. Enter serum phosphate: Type the serum phosphate and select its unit. The tool converts both to mg/dL before multiplying. 3. Read the product and risk flag: The tool reports the Ca x P product in mg squared per dL squared and flags whether it exceeds the elevated-risk threshold. FAQ: Q: What is the calcium-phosphorus product? A: It is serum calcium multiplied by serum phosphate, both in mg/dL, giving units of mg squared per dL squared. In chronic kidney disease a high product reflects an excess of mineral that can deposit in blood vessels and soft tissue, driving calcification. Q: What threshold is considered elevated? A: A Ca x P product above 55 mg squared per dL squared is the classic threshold associated with increased vascular and soft-tissue calcification risk in dialysis patients. Some guidelines treat values above 70 as markedly high and a trigger for urgent management. Q: How do you convert mmol/L to mg/dL? A: Calcium in mmol/L is multiplied by 4.0 to get mg/dL, and phosphate in mmol/L is multiplied by 3.1. These factors come from the atomic and molecular weights and let the product be computed in the conventional mg-based units regardless of how the lab reports values. Q: Why is this product clinically useful? A: It condenses two of the mineral-bone-disorder labs into one number that correlates with the risk of metastatic calcification, calciphylaxis, and cardiovascular events. It guides phosphate binder use, dietary phosphate restriction, and dialysis adjustments. Q: Is the product still recommended on its own? A: Current KDIGO guidance emphasises treating calcium and phosphate individually rather than the product alone, because the product can be normal while one component is dangerously abnormal. The product remains a useful at-a-glance flag but should never replace the individual values. #### Cell Doubling Time Calculator URL: https://geratools.com/cell-doubling-time Calculate cell population doubling time from initial and final counts and elapsed time using the exponential growth formula Td = t x ln(2) / ln(N2/N1). Also reports number of doublings and specific growth rate. Built for cell culture, cancer biology, and bioprocess labs. Runs in your browser. How to use: 1. Enter the starting count: Type the cell count or density at the first time point, taken during exponential growth. 2. Enter the final count and time: Type the count at the second time point and the number of hours that elapsed between the two measurements. 3. Read the doubling time: The tool applies the exponential growth formula and returns the doubling time, the number of doublings, and the specific growth rate. FAQ: Q: What is population doubling time? A: It is the time a growing cell population takes to double in number during exponential growth. It is a fundamental descriptor of how fast a cell line proliferates and is widely used to compare cell lines, treatments, and culture conditions. Q: Which formula does this use? A: It uses the exponential growth model N2 equals N1 times 2 to the power t over Td. Solving for Td gives Td equals t times the natural log of 2 divided by the natural log of N2 over N1. This assumes growth was exponential across the interval. Q: Why must counts come from the log phase? A: The formula assumes exponential growth. During lag phase cells are not yet dividing and during stationary or death phase growth has stalled, so counts from those phases give a doubling time that does not reflect true proliferation. Take both readings while the culture is actively dividing. Q: What does the specific growth rate mean? A: The specific growth rate, often written mu, is the instantaneous fractional increase per hour, equal to the natural log of N2 over N1 divided by time. It relates to doubling time by Td equals ln(2) divided by mu and is the rate term used in bioprocess and chemostat work. Q: Can I use cell density instead of total count? A: Yes. Any measure proportional to cell number works, such as cells per mL, confluence percentage, or optical density, as long as both readings use the same units. The ratio N2 over N1 is what matters, so the units cancel out. #### GC Content Calculator URL: https://geratools.com/gc-content-calculator Accepts a raw DNA or RNA sequence and computes GC content as a percentage of valid bases, with AT content, full base composition, length, and an estimated melting temperature. For primer design, cloning, sequencing QC, and genome analysis. How to use: 1. Paste your sequence: Enter any DNA or RNA sequence; spaces, numbers, and FASTA headers are stripped automatically before counting. 2. Read the GC percentage: The tool counts guanine and cytosine over all valid bases and reports GC content, AT content, and the full base breakdown. 3. Check the melting temperature: For primers it also estimates a melting temperature using the appropriate short or long oligo formula as a quick design guide. FAQ: Q: How is GC content calculated? A: It is the number of guanine and cytosine bases divided by the total number of valid bases, expressed as a percentage. Ambiguity codes and unknown characters are excluded from the denominator so they do not distort the result. Q: Why does GC content matter? A: GC base pairs have three hydrogen bonds versus two for AT, so GC rich sequences are more thermally stable. This affects primer melting temperature, PCR conditions, secondary structure, and even how a region behaves during sequencing, making GC content a core design parameter. Q: How accurate is the melting temperature estimate? A: The estimate uses the Wallace rule for oligos under fourteen bases and a basic GC formula for longer ones. These are quick approximations that ignore salt concentration and neighbouring bases, so use a nearest-neighbour model for precise primer design. Q: Does the tool handle RNA? A: Yes. Uracil is counted as the AT-side partner of adenine, so RNA sequences give a correct GC content. You can paste DNA, RNA, or a mix, and any thymine or uracil is treated as a non-GC base. Q: What happens to spaces, numbers, or FASTA headers? A: All non-letter characters are removed before counting, so line numbers, spaces, and newlines do not interfere. Stray letters that are not valid bases are counted separately as ambiguous and excluded from the GC calculation. #### IGF-1 Standard Deviation Score Calculator URL: https://geratools.com/growth-hormone-igf1-sds Calculates IGF-1 SDS from a measured value, patient age, and sex using lambda-mu-sigma (LMS) reference data to standardise results across assay platforms. Built for paediatric and adult endocrinologists assessing growth hormone status. How to use: 1. Enter the measured IGF-1: Type the laboratory IGF-1 result and confirm the unit shown matches your report (ng/mL). 2. Enter age and sex: Enter the patient's age in years and select biological sex, which select the correct reference distribution. 3. Read the SDS: The tool interpolates an age- and sex-specific reference, converts the value to a standard deviation score, and flags whether it falls inside or outside the normal range. FAQ: Q: What is an IGF-1 SDS and why is it used? A: An IGF-1 standard deviation score (also called a z-score) expresses how far a measured IGF-1 lies from the age- and sex-matched population mean, in standard deviations. Because raw IGF-1 falls steeply with age and differs by sex, an SDS lets clinicians compare a result against the right peer group rather than a single fixed range. Q: How is the SDS computed from the reference data? A: This tool uses the LMS method. Each age and sex has three parameters: L (skewness, Box-Cox power), M (median), and S (coefficient of variation). The score is ((value/M)^L − 1) / (L × S), which corrects for the right-skewed distribution of IGF-1. When L is near zero a logarithmic form is used instead. Q: Are the reference values assay-specific? A: Yes. IGF-1 immunoassays differ substantially between manufacturers, so a result should ideally be scored against the reference panel that matches the assay used. The values here are illustrative LMS-style references and should be replaced with your laboratory's own validated panel before clinical use. Q: What SDS range is considered normal? A: Most laboratories treat an IGF-1 SDS between −2 and +2 as within the reference interval, capturing roughly 95 percent of healthy individuals. A low SDS supports investigation for growth hormone deficiency, while a high SDS may suggest acromegaly or excess growth hormone, always interpreted with clinical context. Q: Can this replace a stimulation test? A: No. IGF-1 SDS is a screening and monitoring aid, not a diagnostic substitute. Growth hormone deficiency and excess are confirmed with dynamic testing such as stimulation or suppression tests, alongside imaging and full clinical assessment. #### Haematologic Response Criteria Calculator (CR/VGPR/PR) URL: https://geratools.com/hematologic-response-criteria Enter baseline and post-treatment serum and urine M-protein, bone marrow plasma cell percentage, and immunofixation status to classify multiple myeloma response as sCR, CR, VGPR, PR, MR, SD, or PD per IMWG 2016 criteria. How to use: 1. Enter M-protein values: Type the baseline and post-treatment serum M-protein in g/dL and urine M-protein in mg per 24 hours. 2. Add marrow and immunofixation status: Enter the bone marrow plasma cell percentage and tick whether serum and urine immunofixation are negative. 3. Read the response category: The tool applies the IMWG hierarchy and returns the highest response category met, with the percentage reductions used. FAQ: Q: Which response categories does this cover? A: It classifies sCR (stringent complete response), CR, VGPR, PR, MR, SD, and PD using the IMWG 2016 uniform criteria for measurable disease. The highest category whose thresholds are met is reported. Q: What defines a complete response? A: CR requires negative serum and urine immunofixation, disappearance of any soft-tissue plasmacytomas, and bone marrow plasma cells below 5%. Stringent CR adds a normal serum free light-chain ratio and absence of clonal plasma cells. Q: How is VGPR distinguished from PR? A: VGPR requires at least a 90% reduction in serum M-protein with urine M-protein below 100 mg per 24 hours, or M-protein detectable only by immunofixation. PR requires only a 50% serum reduction with a 90% urine reduction or urine below 200 mg per 24 hours. Q: When is progressive disease flagged? A: The tool flags PD when serum or urine M-protein rises by 25% or more from the lowest response value. PD is checked before all response categories because it overrides them. Q: Does this assess minimal residual disease? A: No. MRD-negative status requires flow cytometry or next-generation sequencing on marrow and is not modelled here. This calculator handles serum and urine M-protein based response only. #### Maximum Allowable Blood Loss (MABL) Calculator URL: https://geratools.com/maximum-allowable-blood-loss Calculates maximum allowable blood loss from estimated blood volume, initial haemoglobin, and a lowest acceptable haemoglobin, defining the intraoperative point at which transfusion becomes necessary. Used by anaesthetists and blood management teams. How to use: 1. Enter weight and patient type: Provide body weight and patient category to compute estimated blood volume in millilitres. 2. Set haemoglobin thresholds: Enter the starting haemoglobin and the lowest acceptable haemoglobin for this patient and operation. 3. Read maximum allowable blood loss: The tool returns the volume of blood loss permitted before transfusion is indicated. FAQ: Q: What formula does this use? A: It uses MABL = EBV x (Hi - Hf) / Hi, where EBV is estimated blood volume, Hi is the initial haemoglobin, and Hf is the lowest acceptable haemoglobin. This is the standard average-method formula taught in anaesthesia. Q: How is estimated blood volume calculated here? A: EBV is weight multiplied by an average blood volume coefficient that depends on patient type, around 70 mL/kg for adult males and 65 mL/kg for adult females, with higher values for children and neonates. Q: Can I use haematocrit instead of haemoglobin? A: Yes. The same formula works with haematocrit because the ratio cancels units, so MABL = EBV x (Hcti - Hctf) / Hcti gives an equivalent result. Use whichever value your unit reports, but be consistent. Q: Does reaching MABL mean transfusion is mandatory? A: Not automatically. MABL is a planning estimate of when the chosen haemoglobin floor is reached. The decision to transfuse also considers ongoing bleeding, haemodynamics, comorbidity, and the patient's tolerance of anaemia. #### 10× Medication Error Detection — Dose Plausibility Checker URL: https://geratools.com/medication-error-dose-check Check a calculated drug dose against published weight-based safe ranges for 25 common drugs to catch 10-fold decimal-point prescribing errors before administration. A bedside plausibility screen for pharmacists and prescribers. How to use: 1. Pick the drug: Select the medication from the list. Its published safe range in mg per kg per dose loads automatically. 2. Enter weight and dose: Type the patient weight in kilograms and the calculated dose in milligrams that you are about to administer. 3. Read the verdict: The tool shows the weight-based safe range and flags whether the dose is within range, outside it, or a likely 10-fold decimal-point error. FAQ: Q: What is a 10-fold medication error? A: It is a dosing mistake where a misplaced decimal point makes the dose ten times too high or too low — for example 50 mg written instead of 5 mg. These errors are common, easy to miss, and can be fatal, so a plausibility check is a valuable second line of defence. Q: How does the tool detect a 10-fold error specifically? A: It compares the entered dose to the weight-based safe range. If the dose is at least ten times the maximum safe dose, it flags a likely 10-fold overdose; if it is at most one tenth of the minimum, it flags a possible 10-fold underdose. Q: Are the mg per kg figures definitive? A: No. They are typical single-dose values for guidance only. Actual safe doses vary with indication, route, age, and renal or hepatic function. Always confirm against your local formulary or BNF before giving any medicine. Q: Why might a low dose flag without being an error? A: A dose below the usual range is often intentional, such as a reduced dose for renal impairment, hepatic impairment, or a frail elderly patient. The tool flags it so you confirm the intent rather than assuming an error. Q: Can this replace a prescribing or pharmacy check? A: No. It is a plausibility screen designed to catch gross errors, not a prescribing authority. It does not check interactions, allergies, cumulative daily maxima, or formulation. Use it alongside, not instead of, standard verification. #### MELD & MELD-Na Score Calculator URL: https://geratools.com/meld-score Compute the MELD and MELD-Na scores from INR, bilirubin, creatinine, and sodium to estimate 90-day mortality in end-stage liver disease and rank transplant priority. Applies UNOS bounds and dialysis rules. Runs in your browser. How to use: 1. Enter the three core labs: Type serum creatinine, total bilirubin, and INR. Each value below 1.0 is automatically floored to 1.0 per the MELD rule. 2. Add sodium and dialysis status: Enter serum sodium for the MELD-Na correction, and tick the dialysis box if the patient had two or more sessions in the past week. 3. Read the score and mortality band: The tool returns the original MELD, the sodium-adjusted MELD-Na, and an estimated 90-day mortality band. FAQ: Q: What is the difference between MELD and MELD-Na? A: MELD uses creatinine, bilirubin, and INR. MELD-Na adds serum sodium, because low sodium independently predicts worse outcomes in cirrhosis. MELD-Na is now the standard for transplant allocation in most regions because it better discriminates mortality risk. Q: Why are values floored to 1.0? A: The formula takes the natural logarithm of each lab value, and the log of a number below 1 is negative, which would distort the score. UNOS rules therefore set any value under 1.0 to 1.0 before the calculation, and cap creatinine at 4.0 mg/dL. Q: What does the dialysis checkbox do? A: If a patient had two or more dialysis sessions in the prior week, or 24 hours of continuous haemodialysis, their creatinine is set to 4.0 mg/dL regardless of the measured value. This reflects that dialysis masks true renal function. Q: What mortality does a given MELD score predict? A: Roughly, a score of 9 or below carries about 2 percent 90-day mortality, 10 to 19 about 6 percent, 20 to 29 about 20 percent, 30 to 39 about 50 percent, and 40 about 70 percent. These are population estimates and vary by cause of liver disease. Q: Is the score capped? A: Yes. The reported MELD and MELD-Na are bounded between 6 and 40. A score of 40 is the maximum used for allocation, representing the most urgent transplant priority. #### NEWS2 Score Calculator URL: https://geratools.com/news2-score Calculate the UK Royal College of Physicians NEWS2 score from respiratory rate, SpO2 scale, supplemental oxygen, blood pressure, pulse, consciousness, and temperature, with threshold-based clinical escalation guidance for NHS ward assessments. How to use: 1. Enter vital signs: Input respiratory rate, oxygen saturation, blood pressure, pulse, and temperature from the latest observation set. 2. Set the modifiers: Choose the SpO2 scale (1 for most patients, 2 for hypercapnic respiratory failure targets), whether the patient is on supplemental oxygen, and the level of consciousness. 3. Read the score and response: The aggregate NEWS2 total and the recommended monitoring frequency and clinical response appear instantly, including any single-parameter red score. FAQ: Q: What is a NEWS2 score? A: NEWS2 is the National Early Warning Score 2, a standardised system from the UK Royal College of Physicians that aggregates seven physiological parameters into a single score. It is used across the NHS to detect and respond to clinical deterioration in acutely ill adults. Q: What NEWS2 score triggers escalation? A: A total of 0 to 4 is low risk, 5 to 6 (or any single parameter scoring 3) is medium risk requiring urgent review, and 7 or more is high risk needing an emergency clinical response. A single red score of 3 in one parameter mandates urgent review even if the total is low. Q: When should SpO2 Scale 2 be used? A: Scale 2 is used only for patients with a prescribed oxygen saturation target of 88 to 92 percent, typically those with hypercapnic (type 2) respiratory failure such as some COPD patients. The scoring thresholds differ markedly from Scale 1, so the correct scale must be confirmed by a clinician. Q: Does supplemental oxygen affect the score? A: Yes. A patient breathing room air scores 0 for the oxygen parameter, while any supplemental oxygen adds 2 points. This reflects the increased clinical concern when a patient needs oxygen support to maintain their saturations. Q: Is this calculator a substitute for clinical judgement? A: No. NEWS2 is a screening and escalation aid, not a diagnosis. It must be interpreted alongside the full clinical picture, local protocols, and senior review. Always follow your organisation's escalation policy. #### Oxygen Delivery (DO₂) & Consumption (VO₂) Calculator URL: https://geratools.com/oxygen-delivery-calculator Compute systemic oxygen delivery (DO2), consumption (VO2), arterial and venous oxygen content, and the oxygen extraction ratio from cardiac output, haemoglobin and arterial/venous saturations. For intensivists and perfusionists. Runs in your browser. How to use: 1. Enter haemoglobin and saturations: Type haemoglobin in g/dL plus the arterial and mixed-venous oxygen saturations and partial pressures. 2. Enter cardiac output: Add cardiac output in litres per minute, and optionally body surface area to get indexed values. 3. Read delivery, consumption and extraction: The tool returns DO2, VO2, arterial and venous oxygen content and the oxygen extraction ratio, with indexed figures if BSA is given. FAQ: Q: How is oxygen delivery (DO2) calculated? A: Oxygen delivery is arterial oxygen content multiplied by cardiac output. Arterial content (CaO2) equals 1.34 times haemoglobin times arterial saturation, plus 0.0031 times PaO2. DO2 in mL/min equals CaO2 times cardiac output in L/min times 10 to reconcile the units. Q: What is the oxygen extraction ratio? A: The oxygen extraction ratio (O2ER) is the fraction of delivered oxygen that the tissues consume, calculated as VO2 divided by DO2, or equivalently (CaO2 minus CvO2) divided by CaO2. A normal value is around 0.20 to 0.30; a rising ratio signals that delivery is struggling to meet demand. Q: Why is the dissolved oxygen term included? A: Most oxygen is carried bound to haemoglobin, but a small amount is dissolved in plasma, equal to 0.0031 mL per dL per mmHg of PaO2. At normal pressures this is tiny, but it becomes meaningful at high inspired oxygen or in severe anaemia, so it is included for accuracy. Q: What are normal DO2 and VO2 values? A: In a typical adult, oxygen delivery is roughly 950 to 1150 mL/min, the DO2 index 500 to 600 mL/min/m2, oxygen consumption around 200 to 250 mL/min, and the extraction ratio 0.20 to 0.30. These vary with body size, temperature, sedation and metabolic state. Q: What does a low mixed venous saturation tell me? A: A falling mixed venous oxygen saturation (SvO2), typically below about 65 percent, means tissues are extracting more oxygen because delivery is inadequate relative to demand. Causes include low cardiac output, anaemia, hypoxaemia or increased consumption such as fever or shivering. #### Modified Brooke Formula — Burn Fluid Resuscitation URL: https://geratools.com/parkland-modified-brooke Computes the 24-hour Ringer's lactate requirement using the Modified Brooke formula (2 mL x kg x %TBSA), a lower-volume alternative to Parkland, with the same first-8-hour and next-16-hour split and hourly rates. For burns surgeons and critical care teams. How to use: 1. Enter weight and burn extent: Type the patient's weight in kilograms and the percentage of total body surface area burned, estimated with the Rule of Nines or a Lund-Browder chart. 2. Add hours since the burn: Enter how long ago the injury happened so the first-phase rate can be spread over the time remaining in the first eight hours. 3. Read the volumes and rates: The tool gives the 24-hour total, the first-8-hour and next-16-hour volumes, and the hourly infusion rates, with the Parkland total shown for comparison. FAQ: Q: What is the Modified Brooke formula? A: It estimates the first 24 hours of crystalloid resuscitation for a burn as 2 mL of Ringer's lactate per kilogram of body weight per percent of total body surface area burned. It deliberately uses about half the volume of the Parkland formula to reduce the risk of over-resuscitation. Q: How is the total split over time? A: Half the calculated total is given over the first eight hours and the remaining half over the following sixteen hours. Crucially, the clock starts at the moment of injury, not at the time the patient reaches hospital. Q: How does it differ from the Parkland formula? A: Parkland uses 4 mL per kilogram per percent burn, double the Modified Brooke volume. Both share the same 8-hour and 16-hour split. Modified Brooke is favoured by teams concerned about fluid creep and the complications of excessive resuscitation volumes. Q: Should I just follow the calculated number? A: No. The formula gives a starting estimate only. Resuscitation must be titrated to physiological endpoints, principally urine output of roughly 0.5 mL per kilogram per hour in adults, and reassessed frequently as the picture evolves. Q: Does this replace specialist burns care? A: No. It is an educational calculator. Major burns require referral to a burns centre, careful airway and analgesia management, and senior decision-making. Use this only as a cross-check within that framework. #### PCR Master Mix Calculator URL: https://geratools.com/pcr-master-mix-calculator Scale per-reaction PCR component volumes to any number of reactions with a pipetting overage factor, auto-fill nuclease-free water to the reaction total, and keep per-tube reagents like template DNA separate. For molecular biology and diagnostic labs. How to use: 1. Set reactions and overage: Enter how many reactions you need and a pipetting overage percentage so the last tube is not short. 2. List your components: Enter each component's per-reaction volume and tick whether it goes in the shared mix or is added per tube, such as template DNA. 3. Read the scaled volumes: The tool fills water to the reaction total, multiplies each in-mix component by the effective reaction count, and shows the total master-mix volume. FAQ: Q: What is a PCR master mix? A: A master mix is a single pooled batch of the reagents shared by every reaction, such as polymerase mix, primers, and water. Aliquoting one mix into each tube cuts pipetting steps, improves consistency, and reduces well-to-well variation. Q: Why add an overage? A: Every pipetting step loses a little liquid to tips and walls, so a mix made for exactly the number of tubes runs short on the last one. An overage of 5 to 10 percent makes slightly more than needed so each reaction gets its full volume. Q: Should template DNA go in the master mix? A: Usually no. Template differs from sample to sample, so it is added to each tube individually rather than the shared mix. Mark template as a per-tube component and the calculator excludes it from the pooled volume while still counting it toward the reaction total. Q: How is the water volume found? A: Water fills whatever is left after the defined components are subtracted from the total reaction volume. If your listed components already exceed the total, the water comes out negative and you must lower a component or raise the reaction volume. Q: Can I use this for qPCR? A: Yes. List your 2x qPCR mix, primers, probe, and water as in-mix components and your template as per-tube, set the reaction count and overage, and read the scaled volumes. The same arithmetic applies to endpoint PCR and qPCR alike. #### PFA-100 Closure Time Result Interpreter URL: https://geratools.com/platelet-function-closure-time Enter PFA-100 Col/Epi and Col/ADP closure times to classify the platelet function pattern — normal, aspirin effect, or a significant primary haemostatic defect — against standard reference intervals. For haemostasis labs. How to use: 1. Enter Col/Epi closure time: Type the collagen/epinephrine cartridge closure time in seconds, as reported by the PFA-100 analyser. 2. Enter Col/ADP closure time: Type the collagen/ADP cartridge closure time in seconds. The tool compares both against reference intervals. 3. Read the pattern: The tool returns the combined pattern and a differential, distinguishing aspirin effect from a broader platelet or von Willebrand defect. FAQ: Q: What are the normal PFA-100 reference ranges? A: Commonly cited intervals are 84 to 160 seconds for the Col/Epi cartridge and 68 to 121 seconds for the Col/ADP cartridge. Ranges depend on the citrate tube and local validation, so confirm against your own laboratory limits. Q: What does a prolonged Col/Epi with a normal Col/ADP mean? A: This is the classic signature of aspirin or other COX-inhibiting NSAID effect. The epinephrine pathway is more sensitive to cyclo-oxygenase inhibition, so it prolongs first while the ADP cartridge stays normal. Q: When are both cartridges prolonged? A: Prolongation of both Col/Epi and Col/ADP suggests a significant primary haemostatic defect such as von Willebrand disease, intrinsic platelet dysfunction, thrombocytopenia, or severe anaemia. It warrants von Willebrand testing and platelet aggregometry. Q: Does a normal PFA-100 rule out a bleeding disorder? A: No. The PFA-100 is a screening test with limited sensitivity for mild platelet defects and type 1 von Willebrand disease. A normal result does not exclude a clinically relevant bleeding tendency in a patient with a suggestive history. Q: Why is the test affected by haematocrit and platelet count? A: The assay relies on platelets adhering and aggregating under flow within a membrane aperture. A low haematocrit (below about 30%) or low platelet count (below about 100) reduces this process and prolongs closure times independent of true platelet function. #### QuantiFERON-TB Gold Interpretation Calculator URL: https://geratools.com/qft-igra-interpretation Takes the TB-antigen, mitogen, and nil interferon-gamma values from QuantiFERON-TB Gold Plus and applies the QIAGEN decision algorithm to return positive, negative, or indeterminate, with a borderline-zone flag for TB screening. Runs in your browser. How to use: 1. Enter the IFN-γ values: Type the interferon-gamma result in IU/mL for the TB antigen tube, the mitogen tube, and the nil control tube from the QuantiFERON report. 2. Apply the algorithm: The tool subtracts the nil background from the TB antigen and mitogen values and applies the QIAGEN decision thresholds. 3. Read the classification: The result is returned as positive, negative, or indeterminate, with a flag if the antigen-minus-nil value sits in the borderline zone near the cutoff. FAQ: Q: What are the QuantiFERON cutoffs? A: A result is positive when TB antigen minus nil is at least 0.35 IU/mL and at least 25% of the nil value, regardless of the mitogen. It is negative when antigen minus nil is below that threshold and the mitogen minus nil is at least 0.5 IU/mL. If the mitogen response is too low or the nil is too high, the result is indeterminate. Q: Why does a high nil value cause an indeterminate result? A: The nil tube measures background interferon-gamma without stimulation. If the nil exceeds 8.0 IU/mL the background is so high that a true antigen signal cannot be distinguished, so the run is reported as indeterminate and should be repeated. Q: What does an indeterminate mitogen mean? A: The mitogen tube is a positive control that should always trigger a strong immune response. If mitogen minus nil is below 0.5 IU/mL in an otherwise negative pattern, the patient's cells failed to respond even to a universal stimulus, so a true negative cannot be confirmed and the test is indeterminate. Q: What is the borderline zone? A: Values just above the 0.35 IU/mL cutoff, conventionally between 0.20 and 0.70 IU/mL, are less reproducible and a repeat test may flip the result. This tool flags antigen-minus-nil values in that band so you can consider confirmatory retesting even though the formal call is positive or negative. Q: Does this replace the laboratory report? A: No. It reproduces the published QIAGEN decision logic for education and cross-checking. The validated software in the analyser and the issuing laboratory remain the authoritative source, and clinical interpretation must consider TB risk, symptoms, and prior results. #### qPCR Efficiency Calculator from Standard Curve URL: https://geratools.com/qpcr-efficiency-calculator Derive qPCR amplification efficiency and R-squared from the slope of a Ct versus log(template) standard curve using E = (10^(-1/slope) - 1) x 100, with least-squares regression on your entered points. For molecular biologists validating quantitative assays. How to use: 1. Enter your standards: For each point on your standard curve enter the template amount in copies or concentration and its measured Ct value. 2. Add as many points as you ran: Use a dilution series of at least three to five standards spanning several orders of magnitude for a reliable fit. 3. Read efficiency and R-squared: The tool fits a line, reports the slope, efficiency percentage, fold per cycle, and R-squared, and flags whether the assay passes typical acceptance criteria. FAQ: Q: How is qPCR efficiency calculated? A: Efficiency comes from the slope of a line through Ct versus log10 of template amount. The fold change per cycle is 10 raised to the power of minus one over the slope, and efficiency percentage is that value minus one, times one hundred. Q: What slope means 100 percent efficiency? A: A slope of about minus 3.32 corresponds to 100 percent efficiency, meaning the amount of product doubles every cycle. Slopes steeper than minus 3.6 or shallower than minus 3.1 fall outside the generally accepted 90 to 110 percent efficiency band. Q: Why does template go on the x-axis as a log? A: Across a serial dilution the template spans several orders of magnitude, so plotting its base-10 logarithm linearises the relationship with Ct. The regression then has a constant slope from which efficiency is read directly. Q: What R-squared is acceptable? A: An R-squared of 0.98 or higher shows the standards fall tightly on the regression line, indicating consistent pipetting and amplification. A lower value points to pipetting error, poor dilution accuracy, or a standard that should be excluded. Q: What if efficiency is above 100 percent? A: Efficiency above 100 percent is physically impossible and usually signals a problem, most often inhibitors or pipetting error in the more concentrated standards that delay their Ct. Re-run the curve with fresh, accurately prepared dilutions to confirm. #### Reticulocyte Production Index (RPI) Calculator URL: https://geratools.com/reticulocyte-production-index Calculate the corrected reticulocyte count and Reticulocyte Production Index from reticulocyte percent, haematocrit, and RBC maturation time. Classifies bone marrow response to anaemia for haematology and oncology. Runs in your browser. How to use: 1. Enter the reticulocyte percent: Type the reticulocyte count as a percent of red cells from the blood count report. 2. Enter the haematocrit: Provide the patient's measured haematocrit as a percent so the count can be corrected for the degree of anaemia. 3. Read the RPI: The tool corrects the count, divides by the maturation time set by the haematocrit, and reports the production index with interpretation. FAQ: Q: What is the Reticulocyte Production Index? A: The RPI is the reticulocyte percent corrected for both the degree of anaemia and the premature release of reticulocytes from the marrow. It estimates how vigorously the bone marrow is replacing red cells, which a raw reticulocyte percent alone cannot show. Q: Why correct the reticulocyte count? A: Reticulocyte percent is expressed relative to the total red cell mass. In anaemia that mass is reduced, so the same number of reticulocytes appears as a higher percent. Correcting by the ratio of measured to normal haematocrit removes this artefact. Q: What is the maturation time correction? A: In severe anaemia the marrow releases reticulocytes early, so they circulate longer before maturing. Dividing the corrected count by a maturation factor that rises as haematocrit falls (1.0 at 45 percent up to 2.5 below 20 percent) prevents overestimating marrow output. Q: How do I interpret the result? A: An RPI above 3 indicates an adequate hyperproliferative marrow response, typical of haemolysis or acute blood loss. An RPI below 2 indicates an inadequate hypoproliferative response, suggesting a marrow production problem such as iron, B12, or folate deficiency. Q: Is a normal haematocrit needed? A: Yes. The correction compares the patient's haematocrit to a reference normal, conventionally 45 percent for the formula. You can adjust the reference if your laboratory uses a different sex-specific normal value. #### Sputum Gram Stain Quality Checker (Murray-Washington Criteria) URL: https://geratools.com/sputum-culture-gram-stain-quality Takes squamous epithelial cell and polymorph (PMN) counts per low-power field to apply the Murray-Washington criteria — fewer than 10 squames and more than 25 PMNs marks an acceptable lower-respiratory sample. For clinical microbiologists and laboratory scientists. How to use: 1. Count squamous epithelial cells: Scan the Gram-stained slide at low power and record the average number of squamous epithelial cells per low-power field. 2. Count polymorphs: Record the average number of polymorphonuclear neutrophils (PMNs) per low-power field on the same fields. 3. Read the verdict: The tool applies the Murray-Washington thresholds and reports whether the specimen represents lower-respiratory secretions or is contaminated by saliva and should be rejected. FAQ: Q: What are the Murray-Washington criteria? A: They grade a sputum sample by the cells seen at low power. A good lower-respiratory sample has fewer than 10 squamous epithelial cells and more than 25 polymorphs per low-power field. Many squames indicate oropharyngeal contamination by saliva, which makes culture results unreliable. Q: Why reject a sample with many squamous cells? A: Squamous epithelial cells come from the mouth, so their presence in large numbers means the specimen is mostly saliva rather than secretions from the lower airway. Culturing such a sample grows mouth flora and can mislead treatment, so a repeat early-morning deep-cough sample is requested instead. Q: What if there are few squames but few polymorphs too? A: A sample with under 10 squames but fewer than 25 polymorphs is not clearly contaminated but shows little inflammatory response. The tool flags it as borderline or low-yield; it may still be processed in immunosuppressed patients or where a specific pathogen is sought, at the laboratory's discretion. Q: Does this apply to all respiratory samples? A: No. The criteria are validated for expectorated sputum for routine bacterial culture. They are not applied to bronchoalveolar lavage, samples for mycobacteria or fungi, or specimens from intubated patients, where different acceptance rules and quantitative cultures are used. Q: What counts as a low-power field? A: A low-power field is the area seen down the microscope at the 10x objective (roughly 100x total magnification). Counts are averaged across several representative fields rather than taken from a single field, to smooth out uneven distribution on the slide. #### Bacterial Transformation Efficiency Calculator URL: https://geratools.com/transformation-efficiency Calculate bacterial transformation efficiency in CFU per microgram of DNA from colony count, plating volume, total recovery volume, and DNA mass. Built for recombinant DNA labs to benchmark competent cell quality. Runs in your browser. How to use: 1. Count your colonies: Use a control plate with a known amount of supercoiled plasmid and count colonies in the 30 to 300 range. 2. Enter DNA and volumes: Type the nanograms of DNA used, the total recovery volume after outgrowth, and the volume you spread on the plate. 3. Read the efficiency: The tool scales the DNA by the fraction plated and divides colonies by micrograms to give CFU per microgram. FAQ: Q: What is transformation efficiency? A: It is the number of colony-forming units produced per microgram of plasmid DNA. It measures how readily a batch of competent cells takes up and expresses DNA, and it is the standard way to compare cell preparations and protocols. Q: Why scale by the volume plated? A: You almost never plate the entire transformation. If you spread only a tenth of the recovery volume, the colonies you count represent a tenth of the DNA. The calculator multiplies the DNA mass by the plated fraction so the efficiency reflects the DNA actually on that plate. Q: What is a good efficiency? A: Homemade chemically competent cells often reach 1e6 to 1e7 CFU per microgram, which is fine for routine cloning. Commercial high-efficiency cells reach 1e8 to 1e9 and are reserved for library construction or difficult ligations where every transformant counts. Q: Why count only 30 to 300 colonies? A: Below 30 colonies counting error is large, and above 300 colonies start to merge and compete for nutrients, so you undercount. Plates outside this window give unreliable efficiency numbers. Dilute or plate a smaller fraction to land in range. Q: Should I use supercoiled plasmid to benchmark cells? A: Yes. Efficiency depends heavily on the DNA. A pure, supercoiled control plasmid such as pUC19 gives the cleanest benchmark. A ligation mix transforms far less efficiently, so do not compare its numbers against a control-plasmid spec. #### High-Sensitivity Troponin Serial Rise Calculator URL: https://geratools.com/troponin-serial-rise-calculator Compares two high-sensitivity troponin values in ng/L against assay-specific ESC 0h/1h and 0h/3h algorithm thresholds for Roche, Abbott, and Siemens platforms, returning a rule-in, rule-out, or observe verdict with the reasoning. Runs in your browser. How to use: 1. Select assay and algorithm: Choose the laboratory assay and whether you are using the ESC 0h/1h or 0h/3h pathway so the correct thresholds apply. 2. Enter both values: Type the baseline troponin and the repeat value in ng/L, which is the same as pg/mL. 3. Read the verdict: The tool computes the serial change and returns a rule-in, rule-out, or observe verdict with the rule that triggered it. FAQ: Q: Why are the thresholds assay-specific? A: High-sensitivity troponin assays from different manufacturers report different absolute numbers for the same patient, so the ESC publishes separate cut-offs for each. Roche hs-cTnT, Abbott hs-cTnI, and Siemens hs-cTnI all have their own rule-in, rule-out, and delta values, which is why you must select the right assay. Q: What does observe mean? A: Observe is the middle zone where neither rule-in nor rule-out criteria are met. These patients need a further troponin measurement, usually at 3 hours, plus ongoing clinical and ECG assessment before a decision can be made. Q: Is a rule-out enough to discharge? A: No. The algorithm rule-out is only valid alongside a non-ischaemic ECG and low clinical risk, and for the very-low single-value pathway, symptom onset more than three hours earlier. The biomarker is one part of a structured pathway, never the whole decision. Q: What units does this use? A: Nanograms per litre, ng/L, which is numerically identical to picograms per millilitre, pg/mL. Make sure your laboratory reports in these units and not in micrograms per litre, which would be a thousand-fold different. Q: Does a positive troponin always mean a heart attack? A: No. Troponin rises in many conditions including myocarditis, pulmonary embolism, sepsis, renal failure, and tachyarrhythmia. A dynamic rise raises the chance of acute myocardial infarction, but the diagnosis still depends on the clinical picture and ECG. #### Tumour Lysis Syndrome Risk Calculator (Cairo-Bishop) URL: https://geratools.com/tumor-lysis-syndrome-risk Applies a Cairo-Bishop-based risk stratification (low, intermediate, high) from tumour type, white cell count, LDH, and baseline renal or electrolyte involvement to guide prophylactic hydration, allopurinol, or rasburicase before chemotherapy. For oncologists and haematologists. How to use: 1. Select the tumour type: Choose the malignancy category, since highly proliferative tumours such as Burkitt lymphoma and high-count acute leukaemias carry the greatest intrinsic risk. 2. Add laboratory and patient factors: Enter the white cell count and LDH band, and tick any baseline renal impairment, existing electrolyte disturbance, or volume depletion. 3. Read the risk tier and prophylaxis: The tool combines the factors into a low, intermediate, or high risk tier and suggests the matching hydration and uricolytic strategy. FAQ: Q: What is the Cairo-Bishop framework? A: Cairo and Bishop defined laboratory and clinical TLS and a risk model in which the malignancy type, tumour burden (reflected by white cell count and LDH), and the patient's baseline renal function and uric acid determine the likelihood of developing TLS once cytotoxic therapy is started. Q: Which tumours are highest risk? A: Bulky, rapidly dividing, treatment-sensitive tumours top the list — Burkitt lymphoma and lymphoblastic lymphoma, acute lymphoblastic leukaemia with a high white cell count, and acute myeloid leukaemia with a very high count. Most solid tumours are low risk unless very bulky and chemo-sensitive. Q: How does the LDH and white cell count change risk? A: A high lactate dehydrogenase and a high white cell count both signal a large, proliferative tumour mass that will release large amounts of potassium, phosphate, and nucleic acids when it lyses. The tool escalates the tier when these markers are high, in line with published thresholds such as a white cell count above 100. Q: What prophylaxis does each tier need? A: Low risk usually needs vigilant monitoring and oral hydration. Intermediate risk needs intravenous hydration plus allopurinol. High risk needs aggressive intravenous hydration plus rasburicase, with close monitoring of potassium, phosphate, calcium, urate, and renal function. Q: Is rasburicase always safe? A: No. Rasburicase is contraindicated in glucose-6-phosphate dehydrogenase (G6PD) deficiency because it can cause severe haemolysis and methaemoglobinaemia. Screen for G6PD deficiency before use, and follow local protocols; this tool flags rasburicase as an option, not an order. ### Machining & Manufacturing #### Sill Plate Anchor Bolt Layout Calculator URL: https://geratools.com/anchor-bolt-layout-calculator Generates a code-compliant sill plate anchor bolt layout per IRC R403.1.6: maximum 6 ft on center spacing, a bolt within 12 in of each end and corner, and at least two bolts per plate. Takes wall length and outputs the bolt count, even spacing, positions from each corner, and minimum embedment. Runs in your browser. How to use: 1. Enter the wall length: Type the length of the wall or sill plate section in feet, plus the end distance and the maximum bolt spacing you want to use. 2. Flag shear bearing: Check the box if a braced or shear wall bears on this sill so the tool returns the deeper minimum embedment. 3. Read the layout: The tool returns the bolt count, the even spacing, and the position of each bolt measured from the start corner. FAQ: Q: What does IRC require for sill anchor bolts? A: IRC R403.1.6 requires anchor bolts at a maximum of 6 feet on center, a bolt within 12 inches of each plate end and corner, at least two bolts per separate plate section, and a bolt within 12 inches of each plate splice. Minimum bolt diameter is 1/2 inch. Q: How deep must the bolts be embedded? A: The minimum embedment into concrete or grouted masonry is 7 inches under the IRC. Where braced wall panels or shear walls bear on the sill in higher seismic categories, the embedment increases to 15 inches per the bracing provisions. Q: How is the bolt count calculated? A: The tool places a bolt the chosen end distance from each corner, divides the interior span by the maximum spacing, and rounds up to find the number of spaces. The bolt count is the number of spaces plus one, never fewer than two. Q: Why a bolt within 12 inches of each end? A: Bolts near plate ends and corners anchor the most vulnerable parts of the wall against sliding and uplift. Without an end bolt, the unrestrained plate end can lift or shift, so the code caps the end distance at 12 inches. Q: Does this cover high-wind or high-seismic design? A: It applies the prescriptive IRC layout. High-wind and high-seismic zones often require closer spacing, larger bolts, plate washers, or engineered hold-downs. Always check local amendments and any engineered design that governs. #### Center Drill Depth Calculator URL: https://geratools.com/center-drill-depth-calculator Determines how deep to plunge a #1 to #8 center drill to produce a 60-degree center of the correct seat diameter for live or dead centers. Outputs body-drill depth, countersink depth, and the maximum plunge before the countersink exceeds the seat diameter. Runs in your browser. How to use: 1. Pick your center-drill size: Select the standard combined drill and countersink number (#1 to 2. Enter the target seat diameter: Type the diameter of the 60-degree cone you want at the work surface, usually sized to seat your live or dead center. 3. Read the plunge depth: The tool returns total plunge depth, body-drill depth, and the safe maximum plunge before the countersink rim breaks through. FAQ: Q: Why does a center drill make a 60-degree hole? A: Standard center drills are ground with a 60-degree included countersink angle to match the 60-degree point on lathe live and dead centers. The matching angle gives full conical contact, which centers the work and spreads thrust load evenly. Q: How deep should I plunge a center drill? A: Plunge until the countersunk cone reaches the seat diameter you need, but stop before the wide rim of the countersink reaches the surface. The tool computes that geometric depth so the bell mouth is never cut past the body diameter. Q: What is the seat diameter? A: The seat diameter is the diameter of the 60-degree cone at the part surface. It should be slightly larger than the small flat on your center's point so the center seats on the cone, not on the bottom of the pilot hole. Q: What happens if I plunge too deep? A: If you plunge past the point where the countersink rim reaches the body diameter, the thin neck behind the pilot tip can snap, and the bell mouth grows oversize. The tool flags the maximum safe plunge for the size you selected. Q: Do these numbers match Bell-type center drills too? A: The plunge geometry is the same, but bell (radius) center drills add a protective 120-degree chamfer above the 60-degree cone. Use the plain combined-drill dimensions here for the 60-degree seat, then add the bell pass separately. #### 3D Print Clearance & Fit Tolerance Calculator URL: https://geratools.com/clearance-fit-tolerance Recommend clearance gaps in millimetres for interference, press, snug, slide, free-running and loose fits on FDM and SLA prints. Scales with part size and process so printed pins, holes and assemblies fit on the first try. How to use: 1. Choose the fit type: Pick how the parts should mate: interference, press, snug, slide, free-running or loose. Each maps to a different clearance gap. 2. Enter the nominal diameter and process: Type the nominal diameter of the joint and whether you print FDM or SLA. Larger parts and FDM both need a bit more clearance. 3. Apply the gap to your model: The tool gives the diametral clearance and the exact hole and shaft sizes. Adjust either the hole or the shaft by that amount in your CAD. FAQ: Q: What is diametral clearance? A: It is the difference between the hole diameter and the shaft diameter measured across the full diameter. A 0.3 mm diametral clearance means the hole is 0.3 mm wider than the shaft, leaving 0.15 mm of gap on each side. Q: Why does FDM need more clearance than SLA? A: FDM lays down 0.4 mm-wide extruded lines, so it can't resolve fine gaps and tends to over-extrude into holes, shrinking them. SLA cures at far higher resolution, so its clearances are roughly half those of FDM for the same fit. Q: Should I adjust the hole or the shaft? A: Either works — the tool lets you pick. It's often easier to enlarge the hole and leave the mating part at its nominal size, but if the shaft is the printed part and the hole is a bought component, shrink the shaft instead. Q: Why does clearance grow with part size? A: Process error scales gently with dimension — a larger feature accumulates slightly more deviation. The tool adds a small size-proportional term (about 0.5% of nominal) on top of the base fit gap so big joints aren't too tight. Q: Do I still need to test print? A: Yes, once per printer. Over-extrusion, nozzle wear and filament shrinkage shift the real numbers. Print a fit-test (a pin against a row of stepped holes), find the size that gives the feel you want, and use it to calibrate these values for your machine. #### Collet Runout Tolerance Calculator URL: https://geratools.com/collet-runout-tolerance-calculator Estimates expected TIR at the tool tip from a toolholder runout specification at the gauge line and the tool overhang, using a geometric amplification model. Compares ER16, ER32, ER40, and hydraulic or shrink-fit holders so machinists can pick the right holder for precision work. Runs in your browser. How to use: 1. Enter the holder runout spec: Type the toolholder's rated TIR at the gauge line and the gauge-line reference length over which it is specified. 2. Enter the tool overhang: Type how far the cutting tool sticks out past the gauge line. Longer overhang amplifies any angular tilt at the tip. 3. Read the projected tip TIR: The tool returns estimated TIR at the tip and compares it against the spec for ER16, ER32, ER40, and shrink-fit holders. FAQ: Q: What is TIR? A: TIR is Total Indicator Runout, the full sweep a dial indicator reads as a rotating part turns one revolution. It captures both how off-center the tool is and how much it tilts, and it directly affects hole size, surface finish, and tool life. Q: Why does runout get worse with longer overhang? A: A holder spec includes a small angular tilt as well as a centering error. Tilt projects outward along the tool: the farther the tip is from the gauge line, the larger the lateral displacement. Doubling the overhang roughly doubles the tilt-driven part of the tip TIR. Q: Are ER collets less accurate than shrink-fit? A: Generally yes. Good ER collets hold about 0.0002 to 0.0004 in TIR at the gauge line, while shrink-fit and hydraulic holders reach 0.0001 in or better. For micro-tools, reaming, and fine boring the lower runout of shrink-fit meaningfully extends tool life. Q: How is the angular component estimated? A: The model treats the rated TIR as the sum of a centering offset plus a tilt measured over the gauge-line reference length. It projects that tilt to the tool tip and adds the centering offset, giving a conservative estimate of tip TIR for a given overhang. Q: Is this a substitute for measuring? A: No. It is a planning estimate to compare holder classes and overhangs. Always verify with a tenths indicator on the actual assembly, because collet cleanliness, tool shank tolerance, and seating force all shift real runout. #### Drill Feed & RPM per Material Calculator URL: https://geratools.com/drilling-rpm-feed-depth Calculates recommended spindle RPM and feed rate for twist drilling in steel, stainless, aluminum, cast iron, and plastic from drill diameter using cutting speed (SFM) and feed per revolution tables. Includes HSS and carbide recommendations and peck-depth guidance for deep holes. How to use: 1. Enter the drill diameter: Type the drill diameter and choose inches or millimeters; diameter drives both the RPM and the feed-per-revolution recommendation. 2. Select material and tool: Pick the workpiece material and whether the drill is HSS or carbide so the tool uses the correct surface speed and feed values. 3. Read RPM and feed: The tool converts cutting speed to spindle RPM, multiplies feed per revolution by RPM for feed rate, and suggests a peck depth for deep holes. FAQ: Q: How is RPM calculated from cutting speed? A: For inch tooling, RPM equals (cutting speed in SFM times 3.82) divided by the drill diameter in inches. For metric, RPM equals (cutting speed in m/min times 318.31) divided by the diameter in millimeters. Larger drills must spin slower to keep the rim speed within the material's limit. Q: What cutting speeds does it use? A: It uses common shop values: roughly 100 SFM for mild steel, 50 SFM for stainless, 300 SFM for aluminum, and 80 SFM for cast iron with HSS drills. Carbide drills run two to three times faster. These are starting points to refine by sound, chip color, and finish. Q: Why does feed depend on drill diameter? A: Feed per revolution scales with drill size because a bigger drill removes more material per turn without overloading. A rule of thumb is about 0.001 inch per revolution per 1/16 inch of diameter for small drills, increasing for larger ones, which this tool applies. Q: When should I peck drill? A: Peck when the hole depth exceeds roughly three to four times the drill diameter, so chips can clear and coolant can reach the tip. The tool suggests a peck increment of about one diameter per peck for deep holes; reduce it in gummy materials like stainless. Q: Should I slow down for hard or thin material? A: Yes. Reduce speed for hardened or work-hardening alloys to avoid burning the edge, and reduce feed when breaking through thin sheet to prevent grabbing. Always start conservative and increase once the chip and finish look right. #### Fillet Weld Effective Throat Calculator URL: https://geratools.com/fillet-weld-throat-calculator Computes the theoretical throat (0.707 x leg for an equal-leg fillet), the effective throat for convex or concave profiles, and the throat for unequal-leg fillets, plus the weld cross-sectional area used in AWS D1.1 strength calculations. How to use: 1. Enter the weld leg sizes: Type the leg size of the fillet; enter both legs if the weld is unequal-leg, otherwise the tool treats it as an equal-leg fillet. 2. Choose the profile: Select flat, convex, or concave; concave welds have a smaller effective throat and convex welds add reinforcement above the theoretical throat. 3. Read throat and area: The tool returns the theoretical and effective throat plus the weld cross-sectional area used for strength and weld-volume estimates. FAQ: Q: What is the theoretical throat of a fillet weld? A: For an equal-leg fillet weld, the theoretical throat is the perpendicular distance from the root to the hypotenuse, equal to 0.707 times the leg size. A 1/4 inch leg gives a 0.177 inch theoretical throat, which is the dimension used to compute weld strength. Q: How does throat differ for unequal legs? A: For an unequal-leg fillet, the theoretical throat is the leg-times-leg product divided by the square root of the sum of their squares, which is the altitude of the right triangle formed by the two legs. This is smaller than either leg and governs strength. Q: What is the effective throat? A: The effective throat is the throat actually counted in design. AWS treats flat and convex fillet welds as having an effective throat equal to the theoretical throat, ignoring convex reinforcement, while a concave weld's effective throat is measured to the actual weld face and is smaller. Q: Why is the weld area useful? A: The cross-sectional area times the weld length gives weld volume for estimating filler metal and welding time, while throat times length gives the shear-resisting area for strength. The tool reports both so you can size the weld and estimate consumables. Q: Does convexity add strength? A: No. Design strength is based on the throat to the original triangle face, so convex reinforcement is not counted and excessive convexity wastes filler metal and can raise stress concentration. Aim for a slightly flat to flat profile for the best strength-to-deposit ratio. #### Hardness Conversion Calculator URL: https://geratools.com/hardness-conversion-calculator Convert metal hardness between HRC, HRB, HRA, Brinell (10mm/3000kgf), and Vickers, plus an estimated tensile strength in ksi and MPa, using ASTM E140 conversion tables for steel. Out-of-range values are flagged for each scale. How to use: 1. Choose the input scale: Select the scale your measurement is on, such as Rockwell C, Brinell, or Vickers, from the dropdown. 2. Enter the hardness number: Type the measured hardness value. The tool converts it to a master Vickers value first, then to every other scale. 3. Read the equivalents: The table shows the matching HRC, HRB, HRA, HB, HV, and an estimated tensile strength in ksi and MPa. FAQ: Q: How accurate are hardness conversions? A: Conversions between hardness scales are approximate by nature because each test measures resistance to a different indenter under a different load. The ASTM E140 tables used here are the industry standard for carbon and low-alloy steel, and interpolating between rows keeps the error small, but treat the result as a reliable estimate rather than an exact measurement. Q: Why is a value sometimes shown as out of range? A: Each hardness scale has a practical span. Rockwell C is meaningful for hardened steel from roughly 20 to 68 HRC, while Rockwell B suits softer material below about 100 HRB. If your input or its equivalent falls outside the valid window of a scale, the tool flags it rather than guessing a meaningless number. Q: Can I convert hardness to tensile strength? A: For steel there is a well-established empirical link, so the tool estimates tensile strength in ksi and MPa from the Vickers value. This relationship does not hold for non-ferrous metals or stainless steel, and it is only an approximation even for steel, so do not use it for design without test data. Q: Do these conversions work for stainless steel or aluminum? A: No. ASTM E140 has separate tables for austenitic stainless, nickel alloys, and other materials, and the scale relationships differ. This calculator uses the carbon and low-alloy steel table, so do not apply its numbers to stainless, aluminum, brass, or case-hardened surfaces. Q: What is the difference between Vickers and Brinell? A: Vickers uses a diamond pyramid indenter and a small load, giving one continuous scale across soft and hard metals, which is why it works well as a master scale. Brinell presses a hardened ball under a heavy load and reads the indentation diameter, which suits coarse or non-uniform materials but flattens out on very hard steel. #### Heat-Set Insert Hole Size Calculator URL: https://geratools.com/heatset-insert-hole-size Find the recommended boss hole diameter, depth, wall thickness and chamfer for M2 to M6 heat-set threaded inserts in FDM prints. Adjusts for PLA, PETG, ABS and Nylon so molten plastic flows into the knurls and grips. How to use: 1. Select the insert thread size: Choose the insert thread, from M2 up to M6. Each maps to a standard knurl outer diameter and recommended hole. 2. Pick your print material: Select PLA, PETG, ABS or Nylon. Materials that flow more when melted need a slightly smaller hole; tougher ones need more clearance. 3. Model the boss: Use the given hole diameter, depth, boss wall thickness and a small top chamfer in your CAD, then heat-press the insert in square. FAQ: Q: Why is the hole smaller than the insert? A: Heat-set inserts grip by melting the surrounding plastic so it flows into their knurls. The boss hole is deliberately a little smaller than the insert's knurl diameter, so as you press the hot insert in, displaced plastic locks around it for strong pull-out resistance. Q: How deep should the boss hole be? A: Make the hole roughly the insert length plus about half a millimetre, so the insert seats flush or just below the surface and the screw can fully engage without bottoming out on the print. Q: How much wall do I need around the insert? A: Leave enough plastic so the boss doesn't split when the insert is pressed in or when the screw is torqued. A boss outer diameter of roughly two to three times the hole diameter is a safe starting point, more for thin or brittle parts. Q: What temperature should the soldering iron be? A: Set it to the plastic's melt range: around 200 °C for PLA, 230 °C for PETG and 240 °C for ABS. Too cold and the insert won't sink; too hot and you'll char the plastic or push it out of the boss. Press slowly and keep the insert square. Q: Why does Nylon need a larger hole? A: Nylon is tough and flows less freely when heated, so a slightly larger hole gives the insert room to seat without cracking the boss. Increase the hole a touch and apply steady pressure while it's hot. #### Knurling RPM & Feed Calculator URL: https://geratools.com/knurling-calculator Calculate the spindle RPM for knurling a given diameter from a target surface speed, plus infeed and estimated passes. Also checks whether the workpiece circumference tracks evenly with the chosen knurl wheel TPI so the pattern closes cleanly. How to use: 1. Enter the diameter: Type the diameter of the surface to be knurled in inches. 2. Set surface speed and wheel: Choose a surface speed in SFM (around 100 to 150 for steel) and enter your knurl wheel's teeth per inch and total depth to form. 3. Read speed, feed, and tracking: The tool returns the spindle RPM, infeed per pass and pass count, and warns if the circumference will not divide evenly by the knurl pitch. FAQ: Q: What surface speed should I use for knurling? A: Knurling forms the metal by pressure rather than cutting, so it runs slower than turning. A surface speed of about 100 to 150 SFM works for mild steel; use the lower end for harder materials and larger diameters to limit heat and wheel wear. Q: How is knurling RPM calculated? A: RPM equals the surface speed in surface feet per minute times 12, divided by the circumference in inches, which is pi times the diameter. So RPM = (SFM × 12) / (π × diameter), the same speed formula used for turning. Q: What does the tracking check do? A: For the diamond pattern to close cleanly the circumference must contain a whole number of knurl teeth. The tool multiplies circumference by the wheel TPI; if that product is far from a whole number the pattern double-tracks and produces a muddy or doubled diamond. Q: How many passes does knurling need? A: Knurling is usually formed in one to several light passes to the full depth rather than one heavy plunge. The tool divides the total form depth by a conservative infeed per pass to estimate the number of passes; reduce infeed for harder material. Q: Can I adjust the diameter to fix tracking? A: Yes. If the circumference does not divide evenly by the knurl pitch, turning the blank a few thousandths smaller or larger to land on a whole number of teeth often fixes double-tracking. The tool shows the nearest clean diameters above and below. #### Lathe Taper Calculator URL: https://geratools.com/lathe-taper-calculator Calculate compound-rest angle and tailstock set-over for turning tapers specified by included angle, taper per foot, or taper per inch, or by large and small diameters over a length. Covers standard and custom tapers with both methods shown. How to use: 1. Choose how the taper is defined: Select whether you know the included angle, the taper per foot, the taper per inch, or the two diameters across a length. 2. Enter the values: Type the taper figures and, for the set-over method, the overall length of the workpiece between centers. 3. Read both settings: The tool returns the compound-rest angle to set from the cross-slide and the tailstock set-over distance for the same taper. FAQ: Q: What is the difference between the two methods? A: The compound-rest method tilts the top slide to the taper half-angle and cuts short, steep tapers any angle you like, but only as long as the slide travel. The tailstock set-over method offsets the tailstock to turn long, gentle tapers along the whole bed, but only shallow angles. Q: How is the compound-rest angle found? A: The compound is set to the half-angle of the taper, measured from the lathe axis. The half-angle is the arctangent of the radius change divided by the length, which equals arctangent of (taper per inch divided by two). Q: How is tailstock set-over calculated? A: Set-over equals the total workpiece length between centers times the taper per inch, divided by two. Equivalently, it is overall length times (large diameter minus small diameter) divided by twice the tapered length. It only works when the taper runs the full length. Q: What is taper per foot? A: Taper per foot is the change in diameter over twelve inches of length, a common way to specify standard machine tapers. Taper per inch is that figure divided by twelve. Both describe the diameter change, not the radius change. Q: Why does the set-over use total length, not tapered length? A: The tailstock offsets the far center of the whole part, so the geometry depends on the full distance between centers. If only part of the length is tapered, the set-over method distorts the taper, which is why the compound method is preferred for partial tapers. #### Mortise & Tenon Sizing Calculator URL: https://geratools.com/mortise-tenon-strength-calculator Size a mortise and tenon joint from the rail dimensions: tenon thickness at one third of rail thickness, tenon length at 2.5 to 3 times thickness, and mortise wall thickness. Reports long-grain glue area and a conservative shear-capacity estimate by wood species group. How to use: 1. Enter rail dimensions: Type the thickness and width of the rail that carries the tenon, in millimetres. 2. Pick the wood species group: Choose softwood, medium hardwood, dense hardwood, or very dense, which sets the allowable shear used in the strength estimate. 3. Read the sizing and strength: The tool returns the recommended tenon thickness and length, mortise wall thickness, long-grain glue area, and an estimated shear capacity. FAQ: Q: How thick should a tenon be? A: The classic rule is one third of the rail thickness. That ratio leaves two mortise walls each roughly a third of the thickness, balancing the strength of the tenon against the strength of the material around the mortise. The calculator applies this automatically, and you can override it if your stock or design demands. Q: How long should a tenon be? A: A common range is two and a half to three times the tenon thickness for furniture rails, which gives ample long-grain gluing surface without weakening the receiving piece. Deeper mortises up to about five times thickness add strength where the receiving member is wide enough to accept them. Q: Where does a mortise and tenon get its strength? A: Almost all of the glue strength comes from the two tenon cheeks, which meet the mortise long grain to long grain where PVA and similar glues bond strongly. The shoulders are largely end and edge grain and contribute little adhesion, but they close the joint and resist racking. Q: Is the shear capacity figure exact? A: No, it is a conservative estimate. It multiplies the cheek glue area by a typical allowable shear stress for the species group, assuming a clean, well-fitted, fully clamped joint. Real strength depends on fit, glue, clamping, moisture, and grain, so treat the number as guidance, not a rating. Q: Should I add a haunch or draw-bore pin? A: For frame joints where the rail meets a grooved member, a haunch fills the groove and resists twist. A draw-bored peg adds mechanical lock and clamps the shoulders without glue. Both are good practice on doors and frames, though they sit outside the basic sizing this tool covers. #### Shear Pin Design Calculator URL: https://geratools.com/shear-pin-design-calculator Designs a shear pin or shear bolt to fail at a specified overload torque, given the pin moment arm, material ultimate shear strength, and a safety factor. Outputs the required pin diameter, suggests standard stock sizes, and reports working and breakaway torque. How to use: 1. Enter the target overload torque: Type the torque at which the pin should shear to protect the driveline, plus the radius from the shaft center to the pin. 2. Enter material and safety factor: Enter the pin material's ultimate shear strength and a safety factor so the design accounts for fatigue and material scatter. 3. Read the pin diameter: The tool converts torque to shear force, solves for the required cross-section, and reports the pin diameter and nearest standard sizes. FAQ: Q: How does a shear pin protect a machine? A: A shear pin is a deliberately weak link in a driveline. When torque exceeds a set limit, the pin shears before more expensive gears, shafts, or augers can break. Replacing a cheap pin is far easier than repairing the protected machinery. Q: How is the pin diameter calculated? A: Shear force equals the target torque divided by the moment arm. Required cross-sectional area equals that force times the safety factor divided by the material ultimate shear strength. Diameter follows from area for a round pin: d equals the square root of 4 times area over pi. Q: Single or double shear? A: A pin loaded in double shear has two cross-sections resisting the load, so it carries twice the force of a single-shear pin of the same diameter. The tool lets you choose, because most coupling and hub pins are in double shear while many bolts are in single shear. Q: What ultimate shear strength should I use? A: Ultimate shear strength is roughly 60 percent of ultimate tensile strength for ductile steels. Mild steel is around 35,000 psi shear, while a grade-5 bolt is near 60,000 psi. Use the actual stock specification, as a stronger pin shears at a higher torque. Q: Why include a safety factor? A: Real pins see fatigue, stress concentration at the shear plane, and material variation, so a small safety factor (often 1.2 to 1.5) keeps the pin from shearing prematurely during normal peaks while still protecting against true overloads. #### Sheet Metal Bend Allowance Calculator URL: https://geratools.com/sheet-metal-bend-allowance-calculator Compute bend allowance, bend deduction, and outside setback for any bend from 0 to 180 degrees using the standard neutral-axis formula. Enter thickness, inside radius, and K-factor to get the flat-pattern blank length for accurate press-brake layout. How to use: 1. Enter the bend parameters: Type the material thickness, the inside bend radius, the bend angle in degrees, and the K-factor for your material and forming method. 2. Add the flange legs: Optionally enter the two outside leg lengths so the tool can return the full flat-pattern blank length, not just the allowance. 3. Read allowance and blank size: The calculator returns bend allowance, bend deduction, outside setback, and the flat blank length you cut before bending. FAQ: Q: What is bend allowance? A: Bend allowance is the arc length of material along the neutral axis as it wraps around the bend radius. Because the neutral axis neither stretches nor compresses, this length is what you add between the flat flanges to lay out the part before bending. Q: How does bend allowance differ from bend deduction? A: Bend allowance is added to the inside flange dimensions, while bend deduction is subtracted from the sum of the outside flange dimensions. Both describe the same bend, just measured from different reference points, and you pick whichever matches how your drawing is dimensioned. Q: What is the K-factor? A: The K-factor is the ratio of the distance from the inside surface to the neutral axis, divided by the material thickness. It typically falls between about 0.3 and 0.5 and depends on the material, the bend method, and the radius-to-thickness ratio. A test bend gives the most reliable value. Q: Which formula does this tool use? A: Bend allowance equals the bend angle in radians times the quantity inside-radius plus K-factor times thickness. Outside setback is the tangent of half the angle times inside-radius plus thickness, and bend deduction is twice the setback minus the bend allowance. Q: Why is my finished part slightly off? A: K-factor and springback vary with tooling, material batch, and grain direction. The math here is exact for the inputs you give, but the real K-factor for your setup may differ, so always confirm with a sample bend before running a production batch. #### Structural Bolt Pretension Torque Calculator URL: https://geratools.com/structural-bolt-torque-calculator Converts the AISC and RCSC required minimum bolt pretension to installation torque using T = K x D x F with a default 0.20 nut factor for clean dry bolts. Covers A325 and A490 bolts from 5/8 to 1-1/2 inch and metric M16 to M36 in class 8.8 and 10.9. Runs in your browser. How to use: 1. Choose the unit system: Select imperial for A325 or A490 bolts, or metric for class 8.8 and 10.9 bolts. 2. Pick the bolt and grade: Choose the bolt diameter and its grade or property class so the tool loads the code-required minimum pretension. 3. Set the nut factor: Enter the nut factor K, defaulting to 0.20 for clean dry bolts or about 0.15 when lubricated, and read the installation torque. FAQ: Q: What is the torque-tension equation? A: It is T = K x D x F, where T is installation torque, K the nut factor, D the nominal bolt diameter, and F the required pretension. Most of the applied torque overcomes thread and nut-face friction; only a fraction becomes clamp load. Q: Where does the required pretension come from? A: The minimum pretension values are taken from RCSC and AISC Table J3.1, which is roughly 70 percent of the bolt tensile strength times its stress area. They set the clamp load needed for pretensioned and slip-critical joints. Q: What nut factor K should I use? A: Use 0.20 for clean, dry, as-received bolts and about 0.15 to 0.18 when the threads and nut face are lubricated. K is highly sensitive to surface condition, so it should be verified by lot rather than assumed. Q: Is torque control the preferred installation method? A: No. Because K varies so much, RCSC favours turn-of-nut, calibrated wrench, twist-off tension-control bolts, or direct-tension-indicator washers. Plain torque is the least reliable method and should be calibrated against a bolt tension device. Q: Why does a lubricated bolt need less torque? A: Lubrication lowers friction between the threads and under the nut face, which lowers the nut factor K. With a smaller K, less torque is needed to reach the same clamp load, but over-torque risk also rises if K is mis-estimated. #### Theoretical Surface Finish (Ra) Calculator URL: https://geratools.com/surface-finish-calculator Estimate theoretical turning surface roughness Ra using the standard insert formula Ra ≈ f² / (8R). Enter feed per revolution and nose radius to get Ra in microinches and micrometres, with a reference chart of achievable finishes by process. How to use: 1. Enter feed per revolution: Type the feed in inches per revolution that the lathe is using for the finishing pass. 2. Enter the insert nose radius: Type the nose radius of the turning insert in inches; it is printed in the insert designation and the tool maker's catalogue. 3. Read theoretical Ra: The tool returns theoretical Ra in microinches and micrometres and shows where that lands against typical process ranges. FAQ: Q: What formula is used for theoretical Ra? A: The widely used turning approximation is Ra ≈ f² / (8R), where f is feed per revolution and R is the insert nose radius, both in the same length unit. It models the scallops left between successive feed marks as the rounded nose sweeps the surface. Q: Why is my real finish rougher than the theoretical value? A: Theoretical Ra only counts the geometric feed-mark scallops. Real finish is also affected by built-up edge, tool wear, vibration, chatter, material tearing, and machine rigidity, all of which add roughness on top of the geometric minimum. Q: How do I get a smoother finish? A: Because Ra scales with the square of feed and inversely with nose radius, halving the feed cuts theoretical Ra to a quarter, and doubling the nose radius halves it. Reducing feed and using a larger nose radius are the two main geometric levers. Q: What are the units of Ra? A: Ra is an average roughness, usually quoted in microinches (µin) in the United States or micrometres (µm) elsewhere. One micrometre equals about 39.37 microinches. This tool shows both so you can match either drawing callout. Q: Does a larger nose radius always help? A: It improves finish but increases radial cutting force and the tendency to chatter on slender parts. On thin or overhung work a very large nose radius can deflect the part or induce vibration that makes the real finish worse despite the better theoretical number. #### Thread Pitch Calculator URL: https://geratools.com/thread-pitch-calculator Convert threads-per-inch to pitch in millimeters or metric pitch to TPI, and calculate the major, pitch, and minor diameters for 60-degree Unified and metric, 29-degree Acme, and Buttress thread profiles. Useful for lathe thread cutting and gauge selection. How to use: 1. Convert pitch and TPI: Choose a direction and enter either threads per inch or pitch in millimeters; the tool shows the equivalent in both unit systems. 2. Optionally add diameters: Pick the thread profile and enter the major diameter in inches to compute pitch and minor diameters. 3. Read the results: Use the converted pitch for gauge selection and the diameters for thread-cutting setup or inspection. FAQ: Q: What is the difference between pitch and TPI? A: Pitch is the distance from one thread crest to the next, used in metric threads in millimeters. TPI counts how many threads fall in one inch, used in inch threads. They are reciprocals scaled by 25.4: pitch in mm equals 25.4 divided by TPI. Q: How are the pitch and minor diameters found? A: For 60-degree Unified and metric threads the pitch diameter is the major diameter minus 0.6495 times the pitch, and the basic minor diameter is the major minus 1.2269 times the pitch. These constants come from the standard thread-form geometry. Q: Why do Acme threads use different constants? A: Acme threads have a 29-degree included angle and a square-ish profile, so their pitch and minor diameters subtract roughly half and one full pitch respectively rather than the 60-degree factors used for UN and metric threads. Q: Can I use this to set up a lathe? A: Yes. The pitch tells you the leadscrew setting, and the pitch and minor diameters give the target you cut to and the depth to feed in. Always verify a finished thread with a gauge or mating part before relying on the numbers. Q: Why is the Buttress profile marked approximate? A: Buttress threads come in several pressure-flank angle variants and the exact diameters depend on the standard chosen. The tool uses a representative single-depth approximation, so confirm against the specific Buttress standard for critical work. #### Welding Heat Input Calculator URL: https://geratools.com/welding-heat-input-calculator Compute welding heat input from voltage, current, and travel speed for SMAW, GMAW, FCAW, SAW, and GTAW. Applies the correct thermal efficiency factor and reports both arc energy and effective heat input in kJ/mm and kJ/in. How to use: 1. Select the process: Choose SMAW, GMAW, FCAW, SAW, or GTAW so the calculator applies the right thermal efficiency factor. 2. Enter the welding parameters: Type the arc voltage, the welding current in amps, and the travel speed, then pick the speed unit. 3. Read the heat input: The tool reports both raw arc energy and the effective heat input that actually enters the plate, in kJ/mm and kJ/in. FAQ: Q: What is the welding heat input formula? A: Heat input equals voltage times current times 60, divided by 1000 times the travel speed in mm per minute, giving kilojoules per millimetre. Multiply by 25.4 to convert kJ/mm to kJ/in. The 60 converts amp-volts (watts) into energy per minute of arc time. Q: Why apply a thermal efficiency factor? A: Not all arc energy reaches the workpiece; some radiates and convects away. ISO/TR 18491 gives typical efficiencies of about 1.0 for submerged arc, 0.8 for stick, MIG, and flux-cored, and 0.6 for TIG. The effective heat input is the arc energy multiplied by that factor. Q: Why does heat input matter for procedure qualification? A: Heat input controls the cooling rate of the weld and heat-affected zone, which sets the final microstructure, hardness, and toughness. Codes such as AWS D1.1 limit the qualified range, so welders must stay between the minimum and maximum recorded on the procedure qualification record. Q: What happens if heat input is too high or too low? A: Too high and the weld cools slowly, causing grain growth, a soft heat-affected zone, and reduced toughness. Too low and it cools quickly, which can harden hardenable steels and promote hydrogen cracking. The correct window depends on the alloy and thickness. Q: Does this work for SAW and TIG? A: Yes. The formula is identical; only the efficiency factor changes. Submerged arc uses about 1.0 because the flux blanket traps almost all the energy, while TIG uses about 0.6 because more heat is lost from the open arc, so the same parameters give a lower effective heat input. ### Electrical & NEC #### Busbar Ampacity Calculator URL: https://geratools.com/busbar-ampacity-calculator Uses the standard bus-bar ampacity rule of thumb — about 1000 A per square inch for copper and 700 A per square inch for aluminum — adjusted for enclosure, stacking, and surface finish to estimate the continuous rating of a rectangular bar for switchgear and panel boards. How to use: 1. Pick the material: Choose copper or aluminum. Copper carries roughly 1000 amps per square inch of cross-section; aluminum about 700, because it conducts less well. 2. Enter the bar dimensions: Type the bar width and thickness in inches and how many bars are stacked per phase. The tool multiplies them to find the cross-sectional area. 3. Adjust for conditions: Tick whether the bar sits in an enclosure (still air reduces cooling) and whether it is plated or dull-finished (which radiates heat better), then read the estimated continuous ampacity. FAQ: Q: What is the rule of thumb for busbar ampacity? A: A common shop rule is about 1000 amps per square inch of cross-section for copper and about 700 amps per square inch for aluminum, for a single bar in free air with a roughly 30 C temperature rise. These are starting estimates, not code values. Q: Why does an enclosure lower the rating? A: Inside a panel the air is still and warm, so the bar sheds less heat by convection. A typical derate is about 20%. Forced ventilation or a larger enclosure improves cooling and recovers some capacity. Q: Why doesn't stacking bars add capacity proportionally? A: When you stack two or three bars, the inner bars are shielded and run hotter, radiating less heat. Each extra bar adds only about 80% of the first bar's capacity, so this tool models stacking with a reduced effective area. Q: Does surface finish really matter? A: Yes. Bright bare copper has low emissivity and radiates heat poorly. A dull, oxidized, painted, or tin/silver-plated surface radiates better and runs cooler, worth roughly 15% more capacity, and plated joints stay cooler under load. Q: Can I use this to design switchgear? A: No — treat it as a sizing sanity check. Final bus-bar selection must meet the temperature-rise limits of UL 891 or IEC 61439, account for skin effect at high currents and AC, joint resistance, and short-circuit withstand. Always confirm against manufacturer tables. #### Cable Tray Fill Calculator (NEC 392) URL: https://geratools.com/cable-tray-fill-calculator Sum cable cross-sectional areas and diameters and compare against NEC 392.22 maximum fill limits for ladder, ventilated-trough, solid-bottom and channel cable trays by tray width from 6 to 36 inches, for both multiconductor and single-conductor cable types. How to use: 1. Select the tray and cable type: Choose the tray type (ladder, ventilated-trough, solid-bottom or channel), the cable type, and the inside tray width. 2. List your cables: For each cable add the quantity and outside diameter, and tick the box if the cable is 4/0 AWG or larger (multiconductor) or 1000 kcmil or larger (single-conductor). 3. Read the verdict: The tool sums areas and diameters, applies the right NEC 392.22 rule, and reports the fill percentage with a pass or fail. FAQ: Q: How does NEC 392.22 limit cable tray fill? A: For multiconductor cables 4/0 AWG and larger, the sum of cable diameters must not exceed the tray width. For smaller cables, the total cross-sectional area must not exceed the allowable area from Table 392.22(A), which depends on tray type and width. Q: Why are 4/0-and-larger cables treated differently? A: Large cables are stiff and lie in a single layer, so the code limits them by the sum of their diameters against tray width rather than by area. Smaller cables can bundle, so an area-fill limit governs them instead. Q: How are mixed cable sizes handled? A: When both large and small cables share a tray, the large-cable diameters occupy part of the width and the remaining width is available for the area-method cables. The tool applies this combination so both rules are satisfied together. Q: Why does a solid-bottom tray allow less fill? A: Solid-bottom trays restrict airflow around the cables, reducing heat dissipation, so NEC Table 392.22(A) gives them a smaller allowable fill area than ladder or ventilated-trough trays of the same width. Q: Does cable tray fill affect ampacity? A: Yes. Fill and the number of conductors interact with the ampacity derating rules in NEC 392.80. Staying within the fill limit is the first step, but you must also confirm the cables carry their required current after any applicable derating. #### Harmonic Derating (K-Factor) Calculator URL: https://geratools.com/harmonic-distortion-derating-calculator Compute the IEEE C57.110 transformer K-factor from per-harmonic current magnitudes and find the standard K-rating needed to safely supply a non-linear load. For electrical engineers sizing transformers in data center and VFD-heavy installations. How to use: 1. Enter the harmonic spectrum: Type the RMS current for each harmonic order from your power-quality meter, in amps or as a percent of the fundamental. 2. Read the K-factor: The tool sums the weighted squares of the harmonic currents and divides by the total RMS squared to produce the K-factor. 3. Select a K-rated transformer: Use the recommended next standard K-rating at or above the computed value to specify or verify your transformer. FAQ: Q: What is a transformer K-factor? A: The K-factor is a weighting that captures how harmonic currents increase eddy-current heating in a transformer. Higher-order harmonics heat the windings disproportionately because the eddy losses scale with the square of frequency, so a K-factor above 1 means the transformer must be derated or K-rated. Q: What units should I enter the harmonic currents in? A: Use any consistent unit. The formula divides the weighted sum of squares by the plain sum of squares, so the absolute reference cancels. Amps from a meter or percent of the fundamental both give the same K-factor. Q: What are the standard K-ratings? A: Transformers are commonly sold as K-1, K-4, K-9, K-13, K-20, K-30, K-40, and K-50. The tool rounds your computed K-factor up to the next standard rating so you specify a transformer that can handle the measured spectrum with margin. Q: When do I need a K-rated transformer? A: Any time the load is non-linear — switching power supplies, VFDs, LED drivers, UPS systems. Data centers and motor-drive installations routinely see K-factors of 4 to 20. A standard K-1 transformer on such a load overheats and loses life rapidly. Q: Does this replace a full thermal study? A: No. The K-factor selects an appropriately rated transformer, but a complete IEEE C57.110 evaluation also accounts for ambient temperature, load profile, and harmonic loss factor for an existing unit. Use this for selection and screening. Q: Can two loads with the same THD have different K-factors? A: Yes, and it is common. The K-factor weights each harmonic by the square of its order, so distortion concentrated at low orders (like the 3rd) gives a much lower K-factor than the same total distortion concentrated at high orders (like the 25th). THD alone cannot tell you the transformer heating; the K-factor can. Q: Is a K-9 transformer derated to one-ninth of its kVA? A: No — that is a common misreading. The K-rating is a selection index, not a derating ratio. A K-9 transformer is wound with extra conductor transposition and cooling to carry the eddy-current losses of a K-factor-9 spectrum at its full nameplate kVA. It is not divided by 9. #### Lighting Power Density (LPD) Calculator URL: https://geratools.com/lighting-power-density-calculator Sums installed fixture wattage per space, divides by floor area to compute lighting power density in W/ft², and compares it against ASHRAE 90.1-2022 building-area method allowances for energy-code compliance on commercial lighting designs. How to use: 1. Pick the building type: Select the ASHRAE 90.1 building-area type so the correct W/ft² allowance applies, then enter the floor area in square feet. 2. List the fixtures: Add each fixture type with its quantity and per-fixture wattage; the tool totals the installed lighting power across all rows. 3. Compare to the allowance: Read the installed LPD in W/ft² and see whether it falls under the allowance, with the remaining wattage budget shown. FAQ: Q: What is lighting power density? A: Lighting power density, or LPD, is the installed lighting wattage of a space divided by its floor area, expressed in watts per square foot. Energy codes cap it so buildings do not install more lighting power than necessary, which directly limits lighting energy use. Q: Which ASHRAE allowances does this use? A: It uses the ASHRAE 90.1-2022 building-area method allowances from Table 9.5.1, such as 0.64 W/ft² for offices and 0.84 for retail. These are whole-building averages; the space-by-space method in Table 9.6.1 sometimes permits more in specific room types. Q: Should I use installed or connected wattage? A: Use the installed power of the luminaires — the total input wattage of each fixture including drivers and ballasts, multiplied by quantity. For LED fixtures use the rated input watts, not the bare LED-board wattage, so the figure reflects what the panel actually serves. Q: Are any lights exempt from the LPD limit? A: Yes. ASHRAE 90.1 Section 9.1 exempts certain lighting such as specialized medical, theatrical, and some display and emergency lighting. Exclude exempt fixtures from the total so they do not inflate the installed density and cause a false failure. Q: Does passing this guarantee code compliance? A: No. LPD is one requirement among several — controls, daylighting, and exterior lighting also apply. The adopted energy code may be the IECC rather than ASHRAE 90.1, and editions and local amendments differ, so confirm the version in force with the authority having jurisdiction. #### Motor Starting (LRA) Current Calculator URL: https://geratools.com/motor-starting-current-calculator Uses NEC Table 430.7(B) NEMA code-letter kVA-per-horsepower bands together with motor HP and voltage to estimate locked-rotor current and starting kVA for generator sizing, conductor protection, and soft-starter or VFD-bypass selection. How to use: 1. Enter horsepower and code letter: Type the motor horsepower and select the NEMA code letter stamped on the nameplate, which sets the locked-rotor kVA per horsepower. 2. Set voltage and phase: Enter the motor voltage and choose single-phase or three-phase so the kVA is converted to amperes correctly. 3. Read the locked-rotor current: The tool returns the starting kVA and the locked-rotor amperes, with the range across the code band shown beneath. FAQ: Q: What is locked-rotor current? A: Locked-rotor current, or LRA, is the high inrush current a motor draws at the instant of starting, before the rotor turns. It is typically five to eight times the running full-load current and determines voltage dip, generator sizing, and the instantaneous trip setting of protective devices. Q: How does the NEMA code letter work? A: Each motor is stamped with a code letter from A to V that NEC Table 430.7(B) maps to a band of locked-rotor kVA per horsepower. A code G motor, for example, draws 5.6 to 6.29 kVA per HP at start, which the tool multiplies by horsepower to get starting kVA. Q: Why does three-phase divide by the square root of three? A: For a three-phase motor, total power equals the square root of three times line voltage times line current. Solving for current gives amps equals kVA times 1000 divided by 1.732 times voltage, which is why the three-phase result is lower than the single-phase result at the same kVA. Q: Should I use the midpoint or the high end of the band? A: The tool reports the band midpoint as the estimate and shows the full minimum-to-maximum range. For conservative generator or protective-device sizing, use the high end of the range, and always confirm against the actual nameplate LRA when it is printed. Q: What do I use this number for? A: Locked-rotor current sizes standby generators, sets the instantaneous magnetic trip of motor breakers, checks voltage-dip on starting, and helps select soft starters and VFD bypass contactors so the equipment can handle the inrush without nuisance tripping. #### NEC Tap Rule Calculator (210% and 100 A Rules) URL: https://geratools.com/nec-100-ampere-tap-rule-calculator Checks the NEC 240.21(B) tap rules — 10-ft rule at 10% of OCPD, 25-ft rule at one-third of OCPD, and the unlimited outside-tap rule — against a proposed tap conductor ampacity and feeder rating. Runs in your browser. How to use: 1. Enter the feeder protection: Type the rating of the overcurrent device protecting the feeder the tap connects to, in amperes. 2. Enter the tap details: Type the proposed tap conductor's ampacity and its length, and tick the box if the tap runs outside the building except at termination. 3. Read the compliance result: The tool evaluates the 10-ft, 25-ft, and outside-tap rules and shows which, if any, the proposed tap satisfies along with the required ampacity. FAQ: Q: What is a tap conductor? A: A tap is a conductor connected to a feeder that is smaller than the feeder and is protected at its origin only by the feeder's overcurrent device. NEC 240.21(B) carves out specific exceptions that let these unprotected taps exist within strict length and ampacity limits. Q: What does the 10-ft tap rule require? A: Under 240.21(B)(1) the tap may not exceed 10 ft, its ampacity must be at least 10 percent of the feeder overcurrent device rating, it must equal or exceed the rating of the device it supplies, and it must stay within the enclosure it serves. Q: What does the 25-ft tap rule require? A: Under 240.21(B)(2) the tap may run up to 25 ft, its ampacity must be at least one-third of the feeder overcurrent device rating, and it must terminate in a single overcurrent device rated no higher than the tap ampacity. Q: Is there a tap rule with no length limit? A: Yes. The outside-tap rule in 240.21(B)(5) allows unlimited length when the tap runs outside the building except at its termination, is protected from physical damage, and terminates in a single overcurrent device located where the conductors enter the building. Q: Is the tap ampacity the bare wire table value? A: No. Tap ampacity is the conductor's allowed current after all temperature and conduit-fill derating. Use the derated value when comparing against the 10 percent or one-third thresholds, not the raw ampacity table figure. #### Multifamily Dwelling Load Calculation (NEC 220.84) URL: https://geratools.com/nec-220-multifamily-load-calc Applies NEC 220.84 optional-method demand factors to the total connected load across all dwelling units to calculate the minimum service ampacity for apartment, condo, and multifamily buildings. Runs in your browser. How to use: 1. Enter the building details: Type the number of dwelling units and the average floor area per unit in square feet. The tool applies 3 VA per square foot for general lighting and receptacles. 2. Add the unit loads: Enter the range, air-conditioning, heating, and other appliance nameplate loads for a typical unit. The tool uses the larger of the A/C or heating load per NEC 220.60. 3. Read the service size: The tool sums the connected load, applies the Table 220.84 demand factor for your unit count, and shows the minimum service ampacity to round up from. FAQ: Q: When can I use the NEC 220.84 optional method? A: The optional method is permitted only when there are three or more dwelling units, every unit is equipped with electric cooking, and every unit has electric space heating, electric air conditioning, or both. If any of these is missing, you must use the standard method in 220.42 through 220.55. Q: What demand factor does a 3-to-5 unit building get? A: Buildings with 3 to 5 dwelling units use a 45 percent demand factor under Table 220.84. The factor drops as the unit count rises because diversity increases, reaching about 28 percent at 40 or more units. Q: Why use the larger of A/C or heating instead of both? A: NEC 220.60 lets you omit the smaller of two noncoincident loads because a unit will not run full heating and full cooling at the same time. The calculator automatically takes the larger of the two values you enter. Q: Does the small-appliance allowance still apply? A: Yes. Each unit gets at least two 1500 VA small-appliance branch circuits plus one 1500 VA laundry circuit. The connected load includes these before the demand factor is applied. Q: What voltage should I divide by? A: For a standard single-phase 120/240 V service, divide the demand load in VA by 240 to get amps. For a three-phase line-to-line service use 208 V; a full three-phase calculation also multiplies by the square root of three for balanced loads. #### NEC Article 430 Motor Circuit Summary Calculator URL: https://geratools.com/nec-article-430-motor-circuit-summary Generate a complete NEC Article 430 motor branch-circuit summary from HP, voltage, phase, and protection type: full-load current from Table 430.248/430.250, 125% conductor, maximum OCPD per Table 430.52, overload range per 430.32, and disconnect rating. Runs in your browser. How to use: 1. Set phase, size, and voltage: Choose single or three phase, pick the motor horsepower, and select the system voltage to pull the table full-load current. 2. Choose the protection type: Select inverse-time breaker, dual-element fuse, non-time-delay fuse, or instantaneous-trip breaker to apply the right Table 430.52 multiplier. 3. Read the full circuit summary: The tool returns FLC, the 125% conductor, the maximum OCPD rounded to a standard size, the overload range, and the disconnect rating. FAQ: Q: Why use the table FLC instead of the nameplate? A: NEC 430.6(A) requires using the full-load current values in Tables 430.248 and 430.250 for sizing branch-circuit conductors, the short-circuit and ground-fault device, and the disconnect — not the motor nameplate. The nameplate FLA is used only for the separate overload protection. This tool reads FLC straight from those tables. Q: How is the conductor sized? A: Per 430.22, a single continuous-duty motor's branch-circuit conductors must carry at least 125 percent of the table full-load current. The tool multiplies FLC by 1.25 and selects the smallest 75 degree Celsius copper conductor whose ampacity meets that value, before any ambient or conduit-fill derating. Q: What sets the maximum overcurrent device size? A: Table 430.52 gives a multiplier of the FLC by protection type: 250 percent for an inverse-time breaker, 175 percent for a dual-element time-delay fuse, 300 percent for a non-time-delay fuse, and 800 percent for an instantaneous-trip breaker. The result is rounded up to the next standard size under 430.52(C)(1) Exception 1 if the motor will not otherwise start. Q: Is the overload device the same as the breaker? A: No. Branch-circuit protection (the breaker or fuse) guards against short circuits and ground faults, while overload protection under 430.32 — typically heaters or an electronic overload in the starter — guards the motor against sustained overcurrent. Overload is sized from nameplate FLA at 115 or 125 percent depending on service factor and temperature rise. Q: Does this account for derating or multiple motors? A: No. It sizes one motor's branch circuit at 75 degree Celsius copper without ambient or conduit-fill adjustment, and it does not size feeders supplying several motors. Apply the relevant correction and adjustment factors and use 430.24 for feeder sizing when more than one motor shares a circuit. #### NEC Kitchen Circuit Requirements Calculator URL: https://geratools.com/nec-kitchen-circuit-calculator Select the appliances in a residential kitchen and get the minimum dedicated circuit list required by NEC 210.52(B) and (C), including two 20-A small-appliance circuits, refrigerator, dishwasher, disposal, microwave, and range, with GFCI and AFCI requirements. Runs in your browser. How to use: 1. Select the kitchen appliances: Check every appliance present, including refrigerator, dishwasher, disposal, microwave, and range, and mark whether the range is electric or gas. 2. Review the required circuit list: The tool always includes the two 20-A small-appliance circuits and adds an individual circuit for each built-in appliance you selected. 3. Confirm protection and conductor sizes: Each circuit row shows the voltage, amperage, conductor gauge, and the GFCI or AFCI protection NEC requires for that circuit. FAQ: Q: Why are two small-appliance circuits always required? A: NEC 210.52(B) requires at least two 20-amp small-appliance branch circuits to serve the countertop and other receptacle outlets in the kitchen. They may also serve the dining room and pantry, but they cannot supply lighting or built-in appliances. Q: Do kitchen countertop receptacles need GFCI protection? A: Yes. NEC 210.8(A) requires GFCI protection for all kitchen receptacles serving the countertop surfaces, and recent editions extend GFCI to nearly all kitchen receptacles regardless of location. The tool flags this on the small-appliance circuits. Q: Does the dishwasher need its own circuit? A: It is standard practice and often required. A built-in dishwasher is typically placed on an individual 15- or 20-amp circuit with GFCI protection per 210.8(D) and AFCI per 210.12, sized to its nameplate rating rather than shared with the disposal. Q: What about a gas range versus an electric range? A: A gas range only needs a 120-volt outlet for the igniter and controls, which the small-appliance circuit can serve. An electric range needs a dedicated 120/240-volt circuit, commonly 40 to 50 amps on 8 or 6 AWG copper, sized to the nameplate. Q: Is AFCI required in the kitchen? A: Yes in recent NEC editions. Section 210.12 requires arc-fault protection for branch circuits supplying kitchen receptacles in dwelling units. Combination AFCI/GFCI breakers or receptacles are commonly used to satisfy both requirements on the same circuit. #### Panel Schedule / Load Center Calculator URL: https://geratools.com/nec-load-center-panel-schedule Creates a panel schedule with circuit number, description, breaker poles, and connected load in VA and amps; auto-balances circuits across legs A and B; totals each leg; and confirms the main breaker rating is not exceeded for permit and field reference. How to use: 1. Set the main breaker: Enter the panel main breaker rating in amps so the tool can confirm no leg exceeds it. 2. Add the circuits: For each circuit enter a description and load as amps or VA, and choose 1-pole (120 V) or 2-pole (240 V). 3. Read the balanced schedule: The tool assigns each circuit to the lighter leg, totals legs A and B, and flags whether the highest leg stays under the main. FAQ: Q: How does the tool balance the legs? A: It places each single-pole circuit on whichever leg, A or B, currently carries less load, which greedily keeps the two legs close in total VA. Two-pole 240-volt circuits draw equally from both legs, so half their VA is added to each. The goal is a balanced panel that avoids overloading one bus. Q: Should I enter load as amps or VA? A: Either works. If you enter amps, the tool multiplies by the circuit voltage — 120 V for a single-pole circuit or 240 V for a two-pole — to get volt-amperes. If you know the VA or wattage directly, enter VA. Internally everything is summed in VA so legs and totals are comparable. Q: Is this connected load or demand load? A: It reports connected load — the straight sum of every circuit. The NEC service-load calculation applies demand factors from Article 220 to lighting, small-appliance, range, and other loads, which reduces the figure used to size the service. Apply those demand factors before sizing the main and feeder. Q: What does the leg amperage tell me? A: Each leg's amperage is its VA total divided by 120 volts, representing the line-to-neutral current that bus carries. The higher of the two legs is what must stay under the main breaker rating. A large imbalance suggests moving circuits between legs to even out the load. Q: Can I use this for a permit drawing? A: It produces the circuit-by-circuit schedule electricians reference and submit, but the official service-load calculation must follow NEC Article 220 with the correct demand factors and any local amendments. Treat the output as a working schedule and field reference, then finalize the load calc per code. #### NEC Chapter 9 Table 9 AC Resistance & Reactance Lookup URL: https://geratools.com/nec-table-9-impedance-lookup Searchable NEC Chapter 9 Table 9 giving effective AC resistance in ohms per 1000 ft for copper and aluminum conductors by AWG/kcmil, plus inductive reactance per conduit type (PVC, aluminum, steel), used in precision voltage-drop and short-circuit calculations. Runs in your browser. How to use: 1. Pick conductor material and size: Choose copper or aluminum and the conductor size in AWG or kcmil from the dropdowns. 2. Pick the raceway type: Select PVC, aluminum or steel conduit so the tool uses the matching reactance and resistance column. 3. Read the impedance values: The tool shows AC resistance and reactance per 1000 ft, and computes the effective impedance at your chosen power factor. FAQ: Q: Why use AC resistance instead of DC resistance? A: At 60 Hz, skin effect and proximity effect raise a conductor's effective resistance above its DC value, especially for large conductors. NEC Table 9 lists the AC resistance so that voltage-drop and fault calculations on alternating-current circuits are accurate, unlike Table 8 which gives DC resistance. Q: Why does conduit type change the numbers? A: The magnetic properties of the raceway affect both reactance and, for steel conduit, the AC resistance. Steel conduit increases inductive reactance and effective resistance compared with non-magnetic PVC or aluminum conduit, so Table 9 gives separate columns for each material. Q: How do I get effective impedance Ze? A: Table 9 footnote gives the effective Z at 0.85 power factor as Ze equals R times power factor plus X times the sine of the load angle. This tool lets you set the power factor and computes Ze, which is the value you multiply by length and current for an accurate AC voltage drop. Q: What is the difference between Table 9 and Table 8? A: Table 8 gives DC resistance and conductor properties like area and strand count, used for simple DC drop and for sizing equipment grounding conductors by area. Table 9 gives the AC resistance and reactance per conduit type at 60 Hz for three single conductors, used for AC voltage drop and short-circuit studies. Q: Are these values for one conductor or a three-phase set? A: NEC Table 9 values are for three single conductors in a raceway, which is the typical three-phase or single-phase circuit arrangement. For a one-way voltage drop you use the per-1000-ft impedance times the one-way length; remember to double the length for single-phase line-to-line two-wire circuits. #### Residential Optional Load Calculation (NEC 220.82) URL: https://geratools.com/residential-optional-load-calc Apply NEC 220.82 to size a dwelling service: sum general load at 100% for the first 10 kVA and 40% thereafter, add the larger of heating or cooling, and get the minimum service in amperes. For electricians doing quick residential permit load calcs. How to use: 1. Enter area and appliances: Type the conditioned floor area in square feet and the total nameplate VA of all fastened appliances including the range, dryer, and water heater. 2. Enter heating and cooling: Provide the air-conditioning load and the electric heating load, and choose the heating type so the correct demand factor applies. 3. Read the service size: The tool applies the 220.82 demand factors, takes the larger of heating or cooling, and returns the minimum service amperes to round up to a standard size. FAQ: Q: When can I use the 220.82 optional method? A: NEC 220.82 may be used when the dwelling is supplied by a single set of 120/240 V or 208Y/120 V three-wire service conductors with an ampacity of 100 A or greater. It is a faster alternative to the standard 220.42 method and usually yields a slightly smaller service. Q: How is the general load demand factor applied? A: Under 220.82(B) the sum of general lighting (3 VA per square foot), the two small-appliance and one laundry circuits (4500 VA), and all appliance nameplates is taken at 100 percent for the first 10 kVA and 40 percent for everything above 10 kVA. This single factor replaces the multi-tier standard tables. Q: Why are heating and cooling not added together? A: NEC 220.82(C) recognizes that a home never runs heating and air conditioning at the same time, so you include only the larger of the two. The tool compares the cooling load against the heating component and carries forward whichever is greater. Q: What heating demand factor should I choose? A: Central electric space heating is taken at 65 percent. A heat pump with supplemental heat, or four or more separately controlled electric heating units, is taken at 100 percent. Picking the right type matters because it can change the service size by a full step. Q: How do I convert the result to a service size? A: Divide the total demand VA by 240 volts to get amperes, then round up to the next standard service: 100, 125, 150, or 200 A. The optional method commonly lets a typical all-electric home fit on a 200 A service. #### Service Entrance Conductor Sizing Calculator URL: https://geratools.com/service-entrance-conductor-sizing Apply the NEC 310.12 dwelling 83% allowance or the NEC 230.42 full-load rule to recommend the service-entrance conductor AWG or kcmil size in copper or aluminum. For electricians designing new services and service upgrades. How to use: 1. Choose the sizing method: Select the dwelling 83% method for single-phase dwelling services or the general method to size directly from a calculated load. 2. Enter the rating or load: For dwelling mode type the service rating in amps; for general mode type the calculated service load after continuous-load adjustments. 3. Read the conductor size: The tool returns the smallest copper or aluminum conductor whose 75 C ampacity meets the requirement, plus the governing NEC basis. FAQ: Q: What is the NEC 310.12 83% rule? A: NEC 310.12 lets single-phase dwelling service and main feeder conductors be sized for 83 percent of the service rating rather than 100 percent. This reflects the natural load diversity in homes and is why a 200 A service is commonly run with 4/0 aluminum instead of a much larger conductor. Q: When should I use the general 230.42 method instead? A: Use the general method for commercial services, three-phase services, or any case that does not qualify for the 310.12 dwelling allowance. There the conductor ampacity must equal or exceed the full calculated service load, including the 125 percent factor on continuous loads. Q: Why does the calculator use the 75 C column? A: Most service equipment terminations are rated 75 C, and NEC 110.14(C) prohibits loading a conductor above its termination rating even if the insulation is rated 90 C. Using the 75 C ampacity keeps the result compliant with typical lugs and breakers. Q: What size is a 200 A copper service conductor? A: Under the 310.12 dwelling allowance a 200 A service needs about 166 A of ampacity (83 percent), which is met by 2/0 copper at 175 A. In aluminum it is 4/0 at 180 A. These are the classic dwelling service sizes the tool returns. Q: Does this size the neutral and grounding conductors too? A: No. The tool sizes the ungrounded service conductors. The grounded neutral is sized per 250.24(C) and 220.61 from the maximum unbalanced load, and the grounding electrode conductor comes from Table 250.66. Size those separately. #### Surge Protective Device (SPD) Sizing Calculator URL: https://geratools.com/surge-protective-device-sizing Uses NEC 285 and IEEE C62.41 zone definitions to recommend the SPD type (1, 2, or 3), the minimum continuous operating voltage (MCOV), and the nominal discharge current based on system voltage and where the device sits in the distribution system. How to use: 1. Choose the system voltage: Select the nominal line-to-neutral voltage of the system you are protecting, such as 120 V on a 120/240 split-phase service or 277 V on a 277/480 wye. 2. Pick the location: Tell the tool whether the SPD sits at the service entrance, on a feeder or sub-panel, or at a branch-circuit point of use. This maps to IEEE C62.41 exposure categories C, B, and A. 3. Read the recommendation: The calculator returns the SPD type, the minimum MCOV the device must exceed, and a recommended nominal discharge current rating. FAQ: Q: What is the difference between Type 1, Type 2, and Type 3 SPDs? A: Type 1 connects on the line side of the service disconnect and handles the highest surge energy. Type 2 installs on the load side at the main panel or sub-panel. Type 3 is a point-of-use device near the equipment and must sit at least 10 m of conductor downstream of a Type 1 or 2. Q: What is MCOV and why does it matter? A: MCOV is the maximum continuous operating voltage an SPD can ride out without conducting. It must exceed the highest expected steady-state line voltage — roughly 1.25 times nominal — so the device does not leak current and overheat during normal voltage swells. Q: What is nominal discharge current (In)? A: In is the surge current an SPD can divert repeatedly without degrading, tested per UL 1449. Service-entrance devices need a high In (often 20 kA) because they face direct lightning energy; point-of-use devices can use a lower In. Q: Does the NEC require surge protection now? A: Yes, in many cases. NEC 230.67 requires SPD protection for most dwelling-unit services, and 700-series articles require it for some emergency and critical systems. This tool helps select a compliant device, but always check the edition adopted locally. Q: Can a Type 3 device alone protect my equipment? A: No. A Type 3 plug-in or point-of-use SPD is a complement, not a substitute. It must coordinate with a Type 1 or Type 2 device upstream so the higher-energy surge is clamped before it reaches the sensitive load. #### VFD Motor Cable Derating & Shielded Cable Calculator URL: https://geratools.com/vfd-motor-cable-derating-calculator Applies NEC 430.22(A) plus NEMA 250 and IEEE 1100 to derate VFD motor conductors at 125% of FLA, correct for ambient and bundling, pick the minimum 75°C copper conductor, and size shielded cable plus a high-frequency drain ground. Runs in your browser. How to use: 1. Enter the motor full-load current: Type the motor nameplate FLA in amps. The tool multiplies it by 1.25 per NEC 430.22(A) for continuous-duty motors. 2. Set ambient and bundling conditions: Choose the ambient temperature band and the number of current-carrying conductors so the tool applies the correct NEC 310 correction and adjustment factors. 3. Read the conductor and cable spec: The result shows the derated required ampacity, the smallest qualifying 75°C copper conductor, and the recommended shielded VFD cable and drain-ground guidance. FAQ: Q: Why is the conductor sized at 125% of motor FLA? A: NEC 430.22(A) requires branch-circuit conductors for a single continuous-duty motor to be rated at no less than 125% of the motor full-load current. This margin covers continuous heating and the slight overload the motor can run at indefinitely. Q: Do VFD output cables really need a special shielded cable? A: Yes for most installations. NEMA 250 and IEEE 1100 recommend a listed VFD or Type WTTC cable with a continuous tape or braid shield to contain common-mode noise and reflected-wave voltage. Standard THHN in conduit lets high-frequency energy radiate and can damage motor bearings. Q: Why size the ground larger than the NEC 250.122 table value? A: The VFD ground carries high-frequency leakage current, not just fault current. A symmetrical drain matched to the phase conductor size, or three symmetrical grounds, keeps the high-frequency return impedance low and reduces shaft voltage and EMI. Q: How do ambient and bundling factors change the answer? A: High ambient temperature and many bundled conductors both reduce a conductor's safe ampacity. The tool divides the 125% requirement by these factors so the conductor you choose, after derating, still clears the required current. Q: Does this size the overload and short-circuit protection too? A: No. This tool sizes the branch-circuit conductor and recommends cable type and grounding only. Motor overload relays, short-circuit/ground-fault protection, and disconnect sizing follow separate NEC 430 Part III and IV rules. ### Shipping, Freight & Trade #### Air Cargo Revenue Tonne-Kilometre Calculator URL: https://geratools.com/air-cargo-revenue-tonne-km-calculator Computes revenue tonne-kilometres, available tonne-kilometres, and weight load factor from actual payload, route distance, and maximum payload. Airline cargo operations and revenue management teams use this for performance reporting and yield management. How to use: 1. Enter the route and payloads: Type the great-circle stage distance in kilometres, the actual revenue payload carried, and the aircraft's maximum payload in tonnes. 2. Add revenue for yield: Optionally enter the cargo revenue earned on the sector to see yield per RTK. 3. Read RTK, ATK, and load factor: The tool multiplies payload by distance for RTK and ATK, then divides them for the weight load factor and computes yield per tonne-kilometre. FAQ: Q: What is a revenue tonne-kilometre (RTK)? A: An RTK is one tonne of paying cargo carried one kilometre. It is the standard unit of air cargo traffic, calculated as actual revenue payload in tonnes multiplied by the stage distance in kilometres. RTKs are summed across all sectors to measure total cargo output. Q: How does ATK differ from RTK? A: Available tonne-kilometres (ATK) measure capacity rather than traffic: maximum payload in tonnes multiplied by distance. ATK is what the aircraft could have carried, while RTK is what it actually carried. The ratio of the two is the weight load factor. Q: What is a good cargo load factor? A: Weight load factor is RTK divided by ATK. Freighter operations often target 65 to 80 percent; belly cargo on passenger flights varies widely. A load factor above 80 percent on a dedicated freighter indicates strong demand and tight capacity discipline. Q: How is cargo yield calculated? A: Yield is revenue divided by RTK, giving revenue per tonne-kilometre. It lets you compare profitability across routes of different lengths and payloads. Falling yield with rising load factor can signal under-pricing of available capacity. Q: Does this account for volumetric (dimensional) weight? A: This tool uses actual weight in tonnes. In practice, low-density cargo is charged on volumetric weight, so the revenue payload you enter should reflect chargeable weight where dimensional weight exceeds actual weight. #### Ballast Calculation Tool URL: https://geratools.com/ballast-calculation-tool Compute the mass and volume of ballast water required to reach a target mean sailing draft after a cargo discharge, using the vessel's TPC and water density. Built for deck officers and port captains planning ballasting operations. How to use: 1. Enter current and target draft: Type the vessel's present mean draft after discharge and the target mean draft you need for safe sailing, both in metres. 2. Add TPC and density: Enter the tonnes-per-centimetre immersion from the hydrostatic tables at the working draft and the density of the ballast water you will load. 3. Read ballast required: The tool converts the draft change into a required mass using TPC, then gives the equivalent water volume from the density you entered. FAQ: Q: What is TPC? A: TPC is tonnes per centimetre immersion: the mass that must be added or removed to change the mean draft by one centimetre. It comes from the ship's hydrostatic tables at a given draft and reflects the waterplane area. Q: How is the ballast mass found? A: Multiply the required draft change in centimetres by the TPC. If you need to sink the ship 30 cm and the TPC is 25 tonnes, you need 30 times 25, which is 750 tonnes of ballast added. Q: Why divide mass by density for volume? A: Mass equals volume times density. To find the volume of water to pump into the tanks, divide the required mass by the water density. Salt water at 1.025 gives slightly less volume per tonne than fresh water at 1.000. Q: Does TPC change with draft? A: Yes, slightly, because the waterplane area changes as the hull immerses. For a modest draft change you can use a single TPC at the mean working draft. For large changes, recompute with TPC at the new draft for accuracy. Q: Does this plan trim across tanks? A: This tool sizes the total ballast needed for the target mean draft. Distributing it between forward, aft, and wing tanks to achieve the desired trim and heel is a separate step using each tank's longitudinal centre and capacity. #### Freight Carbon Footprint & Offset Calculator URL: https://geratools.com/carbon-offset-freight-calculator Apply GLEC-aligned emission factors by transport mode (grams CO2e per tonne-km) to shipment weight and distance to estimate a freight carbon footprint, then price an offset at your chosen carbon price. For sustainability teams and shippers reporting scope 3 logistics emissions. How to use: 1. Enter weight and distance: Type the shipment weight in tonnes and the transport distance in kilometres for the leg you are assessing. 2. Pick the transport mode: Choose road, rail, sea, or air; each carries a different emission factor in grams of CO2e per tonne-kilometre. 3. Read footprint and offset cost: The tool shows total CO2e in kilograms and tonnes, then multiplies by your carbon price to estimate the offset cost. FAQ: Q: What is a tonne-kilometre? A: A tonne-kilometre is one tonne of cargo moved one kilometre. It is the standard freight activity unit because emissions scale with both how heavy a load is and how far it travels. Multiplying tonnes by kilometres gives the activity, which is then multiplied by an emission factor. Q: Where do the emission factors come from? A: The defaults are representative well-to-wheel values aligned with the GLEC Framework and similar logistics inventories: road around 62, rail around 22, sea around 8, and air around 602 grams CO2e per tonne-km. Real factors vary by vehicle, fuel, and load factor, so the tool lets you override the figure. Q: Why is air freight so much worse than sea? A: Air freight emits roughly seventy times more CO2e per tonne-km than sea freight because aircraft burn large amounts of fuel to stay aloft and carry comparatively little cargo. Shifting even part of a shipment from air to sea or rail is the single largest lever for cutting freight emissions. Q: How is the offset cost calculated? A: The tool converts total emissions to tonnes of CO2e and multiplies by the carbon price you enter, in your currency per tonne. Voluntary offset prices commonly range from a few dollars to over fifty per tonne depending on project quality and permanence. Q: Is an offset the same as reducing emissions? A: No. Offsets compensate for emissions you could not avoid by funding reductions elsewhere; they do not eliminate the original emissions. Best practice is to cut footprint first through mode shift, load consolidation, and routing, then offset the residual. #### Colombia Import Duty & Customs Calculator URL: https://geratools.com/colombia-import-duty-customs-calculator Applies Colombia's import structure: arancel (customs duty) on the CIF value, then 19% IVA on CIF plus duty, to compute total taxes and the full landed cost of imported goods, in COP. How to use: 1. Enter the CIF value: Type the customs value — the cost of the goods plus insurance and freight to Colombia (CIF) — in pesos. 2. Enter the duty and IVA rates: Type the arancel (customs duty) rate for your product's HS code and the IVA rate (19% standard, lower for some goods). 3. Read the landed cost: The calculator shows the duty, the IVA on CIF plus duty, total taxes, and the final landed cost. FAQ: Q: How are Colombian import taxes calculated? A: Colombia charges arancel (customs duty) as a percentage of the CIF value, then IVA (VAT) on the CIF value plus the duty. So IVA is levied on a base that already includes the duty, which is why the two cannot simply be added — the duty raises the IVA base. Q: What is the IVA rate on imports? A: The general IVA rate is 19% and applies to most imported goods. Some products carry a reduced 5% rate, and a few are exempt or excluded. Enter the rate that matches your product; the calculator applies it to the CIF-plus-duty base. Q: What duty rate applies to my product? A: The arancel depends on the product's HS tariff classification and ranges roughly from 0% to 20%, with many consumer goods at 5%, 10% or 15%. Free-trade agreements can reduce it to 0% for qualifying origin. Look up your HS code in the Colombian tariff schedule and enter that rate. Q: What is the CIF value? A: CIF stands for Cost, Insurance and Freight — the price of the goods plus the insurance and shipping cost to bring them to Colombia. Customs uses CIF, not the bare product price, as the base for duty, so include freight and insurance for an accurate estimate. Q: Does this include all charges? A: No. It covers the two main levies — arancel and IVA. Real imports may also incur customs-broker fees, port and handling charges, the 4x1000 financial-transaction tax on payments, and antidumping or safeguard duties on specific goods. Treat the result as the core tax estimate. Q: Why does a 0% FTA rate save more than just the duty? A: Because IVA is calculated on the CIF-plus-duty base, removing the duty also removes the IVA that would have been charged on it. On a 10% arancel with 19% IVA, the preferential rate saves 11.9 points of effective tax, not 10 — provided the goods have a valid certificate of origin. Q: Can customs reject my declared CIF value? A: Yes. DIAN maintains reference prices for goods that are frequently under-declared, such as clothing, footwear, and electronics. If your declared value falls below the reference, customs can liquidate duty and IVA on the higher reference value, so keep purchase invoices and freight documents to defend your CIF. #### Container Lashing Force Calculator URL: https://geratools.com/container-lashing-force-calculator Compute transverse, longitudinal, and vertical forces on a deck-stowed container from CSS Code acceleration factors, subtract friction, and find the required lashing tension against the rod MSL. Cargo officers and stowage planners use this to verify lashing adequacy. How to use: 1. Enter the unit mass and accelerations: Type the container mass in tonnes and the transverse, longitudinal, and vertical acceleration factors as multiples of g. 2. Add friction and lashing details: Enter the friction coefficient for the stack base, the number of transverse lashings, the lashing angle to horizontal, and the rod MSL. 3. Read the required tension: The tool reports each external force, the friction restraint, the net force the lashings must take, and the required tension per lashing against the calculation strength. FAQ: Q: What is the CSS Code Annex 13 method? A: Annex 13 of the IMO Code of Safe Practice for Cargo Stowage and Securing is the standard simplified method for checking that securing arrangements can resist the forces from ship motion. It uses acceleration factors as multiples of g that already include roll, pitch, heave, and gravity components. Q: Why does the transverse case usually govern? A: Rolling produces the largest sideways accelerations on a ship, and the gravity component when heeled adds to them. For deck containers the transverse force is therefore normally the critical direction, so this tool sizes the lashings against it. Q: What is MSL and CS? A: MSL is the maximum securing load, the highest load a lashing component may carry. The calculation strength CS is MSL divided by a safety factor, commonly 1.5 for lashing rods, and the required tension must stay below CS for the arrangement to pass. Q: How does friction help? A: Friction between the container base and the deck or the stack below resists sliding before the lashings take any load. The restraint is the friction coefficient times the net downward force, weight minus any upward vertical force, and only the force beyond that needs to be carried by lashings. Q: Can I use this to sign off a real lashing plan? A: No. This is a simplified balance for understanding and first-pass checks. A real plan must use the vessel's approved Cargo Securing Manual, the exact position-dependent accelerations, stack-weight and stack-height limits, and corner-casting strengths. Always follow the manual. #### Container Stuffing & Utilisation Calculator URL: https://geratools.com/container-stuffing-calculator Enter carton dimensions, weights, and quantities to total CBM and gross weight, then see percentage volume utilisation and payload utilisation against 20ft, 40ft, and 40ft High Cube container limits, flagging volume-out versus weight-out. How to use: 1. Add each carton type: Enter length, width, height in centimetres, carton gross weight in kilograms, and quantity for each SKU or carton type in the load. 2. Pick a container type: Choose 20ft, 40ft, or 40ft High Cube. The tool compares your total CBM and weight against that container's usable volume and maximum payload. 3. Read volume and weight utilisation: See total CBM, total gross weight, percentage of volume and payload used, and whether the load is volume-out or weight-out. FAQ: Q: What CBM capacity do you use per container? A: Usable (practical) volumes are about 33 CBM for a 20ft, 67 CBM for a 40ft, and 76 CBM for a 40ft High Cube. Theoretical internal volumes are higher, but real stuffing loses space to pallet gaps and shape, so usable figures are used. Q: What is the maximum payload? A: Typical maximum cargo payloads are around 28,000 kg for a 20ft and 26,500 kg for a 40ft or High Cube, after subtracting tare weight from the gross VGM limit. Always confirm the exact payload on your container's CSC plate. Q: What does volume-out versus weight-out mean? A: Volume-out means you run out of space before hitting the weight limit, typical of light bulky cargo. Weight-out means you reach the weight limit with space to spare, typical of dense goods. The tool tells you which constraint binds first. Q: Why can't I fill 100 percent of the volume? A: Cartons rarely tessellate perfectly and pallets, dunnage, and access aisles consume space. Practical utilisation of 80 to 90 percent of usable CBM is good. Using usable rather than theoretical volume already accounts for some of this. Q: Does this plan the exact stacking pattern? A: No. It is a capacity check on total CBM and weight, not a 3D bin-packing optimiser. Use it to confirm a load fits and to balance volume against weight before you build a detailed stow plan. #### Draft Survey Calculator URL: https://geratools.com/draft-survey-calculator Apply the standard draft survey method to six draft readings with perpendicular and density corrections to find net displacement, then take the difference between initial and final surveys as cargo mass. Marine surveyors and cargo superintendents use it at loading and discharge ports. How to use: 1. Enter the six drafts: Type the forward, aft, and midship port and starboard draft readings for both the initial and final surveys. 2. Add displacement and water density: Enter the displacement read from the ship's hydrostatic tables at each mean draft, and the dock water density. 3. Read the cargo figure: The tool computes the quarter-mean draft, applies the density correction to each displacement, and reports the cargo as the difference between surveys. FAQ: Q: What is a draft survey? A: A draft survey weighs cargo indirectly by measuring how much deeper the ship floats after loading. By reading drafts before and after, converting each to displacement, and subtracting deductibles, the surveyor finds the cargo mass. It is the standard method for bulk commodities. Q: What is the mean of means or quarter mean? A: The six drafts are combined in stages: forward and aft give the mean draft, the midship port and starboard give the midship mean, then those are averaged in a weighted way. The classic quarter mean is (forward plus aft plus six times midship) divided by eight, which corrects for hull deflection. Q: Why is a density correction needed? A: Hydrostatic tables give displacement at a standard water density, usually 1.025 for sea water. If the ship floats in dock water of a different density, displacement must be scaled by actual density divided by table density, or the cargo figure will be wrong. Q: What are deductibles? A: Deductibles are everything aboard that is not cargo: ballast water, fresh water, fuel, lube oil, and constants. Net displacement minus total deductibles gives the light-plus-cargo figure. This tool focuses on the displacement and density steps; subtract your own deductibles for net cargo. Q: How accurate is a draft survey? A: A careful survey is typically within about 0.5 percent on a large bulk carrier, but accuracy depends on calm water, accurate draft reading, correct hydrostatic interpolation, and good density samples. Heavy trim, list, or swell at the marks degrades the result. #### Ireland Import Duty & Customs Calculator URL: https://geratools.com/ireland-import-duty-customs-calculator Free Ireland import duty and customs calculator. Enter the CIF value, freight and your TARIC duty rate to compute customs duty, 23% import VAT and the total landed cost of bringing goods into Ireland — entirely in your browser. How to use: 1. Enter the customs value: Type the goods value plus international freight and insurance. Together these form the CIF customs value Revenue uses. 2. Add your duty and VAT rates: Enter the TARIC duty rate for your commodity code and pick the 23% standard or a reduced Irish import VAT rate. 3. Read the landed cost: The tool shows customs duty, import VAT and the total landed cost you will pay to clear the goods through customs. FAQ: Q: How is Irish import duty calculated? A: Customs duty is a percentage of the CIF value — goods value plus international freight plus insurance. The percentage comes from the EU TARIC tariff for your commodity code and the country of origin, so it ranges from 0% to over 17%. Q: What is the import VAT rate in Ireland? A: The standard Irish import VAT rate is 23%. Reduced rates of 13.5% and 9% apply to specific categories, and most food and children's clothing is zero-rated. VAT is charged on the CIF value plus any customs duty plus inland transport. Q: Is there a duty-free threshold for imports into Ireland? A: Yes. Consignments with an intrinsic value of EUR 150 or less are exempt from customs duty, though import VAT applies from the first euro since the EUR 22 VAT exemption was abolished on 1 July 2021. Q: Do goods from Great Britain attract duty? A: They can. Under the EU–UK Trade and Cooperation Agreement, goods of UK origin that meet the rules of origin are duty-free, but you must hold proof of origin. Goods that do not qualify are charged the standard TARIC rate. Q: Are my figures sent anywhere? A: No. Every calculation runs entirely in your browser. Nothing you type is uploaded or stored, so you can model sensitive shipment values privately. #### Japan Import Duty & Customs Calculator URL: https://geratools.com/japan-import-duty-customs-calculator Estimate the landed cost of goods imported into Japan: customs duty on the CIF value, 10% (or 8% food) consumption tax on value plus duty, the 60% personal-use valuation, and the ¥10,000 de-minimis threshold. Runs in your browser. How to use: 1. Enter the shipment values: Type the goods value, international freight and insurance in yen. Together these form the CIF customs value. 2. Set the rates and import type: Enter the customs duty rate for your product and the consumption tax rate (10% standard, 8% food), then choose personal or commercial import. 3. Read the landed cost: See the customs value, duty, consumption tax, total taxes, and the full landed cost, with the de-minimis waiver applied where it qualifies. FAQ: Q: How is Japan import duty calculated? A: Customs duty is charged on the customs value, which is the CIF total — goods plus international freight plus insurance — converted to yen. The duty rate depends on the product's HS code and can be zero under an economic-partnership agreement. For personal imports, the customs value is assessed at 60% of the price. Q: How does consumption tax apply to imports? A: Japan's consumption tax is charged on the customs value plus the customs duty. The standard combined rate is 10% (national 7.8% plus local 2.2%), and a reduced 8% rate applies to food and non-alcoholic drink. The tool lets you choose the rate and shows the tax base it is applied to. Q: What is the ¥10,000 de-minimis threshold? A: For personal imports, if the taxable value (taken as 60% of the price) is ¥10,000 or less, customs duty and consumption tax are generally waived. Alcohol, tobacco, leather goods and certain other categories are excluded from this waiver. Commercial imports do not get the personal-use valuation. Q: Why is personal-use value only 60% of the price? A: Japan Customs assesses personal (non-commercial) imports on a reduced basis — 60% of the overseas retail price — to reflect that the goods are not for resale. This both lowers the duty and tax base and feeds into the ¥10,000 de-minimis test, which the tool applies automatically when you select a personal import. Q: Is the result exact? A: No. It is an estimate. The actual duty depends on the precise HS code and any preferential EPA rate, and a small customs clearance or handling fee may apply. Always confirm the correct tariff classification with Japan Customs (税関) for a binding figure. #### Ship Fuel Consumption Calculator URL: https://geratools.com/ship-fuel-consumption-calculator Estimate voyage fuel consumption in metric tonnes using the cube-law relationship between speed and daily burn, then apply a bunker price to get total cost. Adjusts a reference daily consumption at a reference speed to your planned speed and distance. For voyage estimators and charterers. How to use: 1. Enter the reference consumption: Type the daily fuel burn in metric tonnes at a known reference speed, taken from the vessel's data sheet or noon reports. 2. Set the voyage speed and distance: Enter the planned speed in knots and the voyage distance in nautical miles. 3. Read fuel and cost: The tool scales daily burn by the cube of the speed ratio, multiplies by voyage days, and applies your bunker price to give total tonnes and cost. FAQ: Q: Why does fuel burn scale with the cube of speed? A: Hull resistance rises roughly with the square of speed, and power equals resistance times speed, so required power and fuel burn scale with the cube. Going 10 percent faster needs about 33 percent more fuel per day, which is why slow steaming saves so much. Q: What is the reference consumption? A: It is the vessel's daily fuel burn in metric tonnes at a stated reference speed, from the trial data, charter party description, or noon reports. The tool scales it to your planned speed, so the more accurate this baseline, the better the estimate. Q: How is the total voyage fuel found? A: Daily burn at the planned speed equals reference burn times (planned speed over reference speed) cubed. Voyage days equal distance divided by speed divided by 24. Multiply daily burn by voyage days for total tonnes, then by bunker price for cost. Q: Does this include port and auxiliary consumption? A: No. It estimates main-engine propulsion fuel at sea only. Add separate allowances for auxiliary engines, boilers, port stays, and manoeuvring, which can be a meaningful share of total bunkers on short voyages with long port times. Q: How accurate is the cube law in practice? A: It is a solid first-order estimate but real exponents range from about 2.7 to 3.5 depending on hull, draft, fouling, weather, and sea state. Use it for planning and charter screening, then refine against actual noon reports for the specific vessel and route. #### Ship Squat Calculator URL: https://geratools.com/ships-squat-calculator Calculate maximum squat and remaining underkeel clearance in open shallow water or a confined channel using the Barrass empirical formula from block coefficient, speed, draught, and depth or blockage factor. Pilots and navigators use this to set a safe speed. How to use: 1. Enter ship and speed data: Type the block coefficient, speed over the ground in knots, static draught, and water depth. 2. Choose the water type: Select open shallow water, or a confined channel and add the beam and channel width so the tool can compute the blockage factor. 3. Read squat and clearance: The tool reports the maximum squat, which end of the ship squats, the dynamic draught, and the net underkeel clearance remaining. FAQ: Q: What is ship squat? A: Squat is the bodily sinkage and change of trim a ship experiences when moving through shallow or restricted water. Faster water flow under the hull lowers the pressure there, drawing the ship deeper and reducing the clearance beneath the keel. Q: Which Barrass formula does this use? A: For open shallow water it uses maximum squat equals Cb times speed to the power 2.08 divided by 100. For a confined channel it uses Cb times the blockage factor to the power 0.81 times speed to the power 2.08 divided by 20, where the blockage factor is the ship's midship area over the channel cross-section. Q: Does the ship squat by the bow or the stern? A: Barrass found that full-form ships with a block coefficient above 0.700, such as tankers and bulk carriers, squat by the bow, while finer ships below 0.700 squat by the stern. The tool reports which end based on the block coefficient you enter. Q: How does speed affect squat? A: Squat rises roughly with the square of speed, since the speed term is raised to the power 2.08. That means halving your speed cuts the squat to about a quarter, which is why slowing down is the most effective way to recover underkeel clearance in shallow water. Q: When is shallow-water effect significant? A: Squat becomes important once the water depth to draught ratio falls below about 1.4, and grows rapidly as the ratio approaches 1.1 to 1.2. Below those ratios you should reduce speed and watch the net underkeel clearance closely throughout the passage. #### Singapore Import Duty & Customs Calculator URL: https://geratools.com/singapore-import-duty-customs-calculator Estimate the landed cost of imports to Singapore. Reflects the free-port reality: customs duty applies only to liquor, tobacco, motor vehicles and petroleum, while 9% GST applies to almost everything on the CIF value plus duty. Runs in your browser. How to use: 1. Pick the goods category: Choose general goods or one of the four dutiable categories — liquor, tobacco, motor vehicles or petroleum. This sets whether any customs duty applies. 2. Enter the CIF value: Type the cost-insurance-freight value of the shipment. For dutiable items with per-unit duties, add the specific duty amount if you know it. 3. Read the landed cost: See the duty, the 9% GST charged on CIF plus duty, and the total landed cost, with a note on what is and is not dutiable. FAQ: Q: Does Singapore charge import duty on most goods? A: No. Singapore is a free port and charges customs duty on only four categories: intoxicating liquor, tobacco products, motor vehicles and petroleum or biodiesel. Everything else — electronics, clothing, books — is duty-free. Only GST applies to those general goods. Q: How much GST do I pay on imports? A: Singapore's GST is 9% and it applies to almost all imports. It is charged on the CIF value (cost, insurance and freight) plus any customs or excise duty. GST relief on low-value imports has been removed, so GST now applies regardless of the shipment's value. Q: What is the CIF value? A: CIF stands for cost, insurance and freight — the value of the goods plus the cost of insuring and shipping them to Singapore. Customs uses CIF as the base for duty and GST, so it is the figure you enter into the calculator. Q: How is duty on cars and liquor worked out? A: Cars carry a 20% excise duty on the customs value plus separate ARF, COE and registration levies. Liquor, tobacco and fuel use specific per-unit duties — per litre of alcohol, per stick, per litre of fuel — so enter the known duty amount manually rather than a percentage. Q: Is this an official customs quote? A: No. It is an educational estimate of the main charges. Specific-rate duties, vehicle levies and clearance fees can change the final bill, so confirm with Singapore Customs or your freight forwarder before relying on a figure. #### Freight Transit Time Estimator URL: https://geratools.com/transit-time-estimator Estimate standard LTL or FTL transit days between any two US states using great-circle distance, a road-detour factor, and carrier service-day bands. Shippers and customer service teams use this to set realistic delivery expectations. How to use: 1. Select origin and destination: Choose the origin and destination US state from the drop-downs; each maps to a representative location for distance. 2. Choose the service type: Pick LTL for less-than-truckload (terminal-to-terminal) or FTL for full truckload (direct point-to-point). 3. Read the transit days: The tool estimates road distance and returns the standard number of business days the lane typically takes. FAQ: Q: How does the estimator calculate distance? A: It computes the great-circle distance between representative points for each state, then multiplies by 1.2 to approximate real road miles, since highways rarely run in a straight line between two places. Q: What is the difference between LTL and FTL transit? A: FTL (full truckload) goes directly and is paced by driver hours-of-service, roughly 500 dispatched miles per day. LTL (less-than-truckload) passes through carrier terminals, adding handling time, so it is grouped into distance bands of two to six days. Q: Are these business days or calendar days? A: Business days. Carriers quote standard transit in working days that exclude weekends and holidays. A 3-day shipment picked up Thursday typically delivers the following Tuesday. Q: Does this account for guaranteed or expedited service? A: No. These are standard service estimates. Guaranteed, expedited, and team-driver services beat them, while remote ZIP codes, residential delivery, and peak congestion can add a day or more. Q: Why is my actual transit different? A: Real transit depends on the specific carrier's terminal network, the exact ZIP codes, day-of-week cutoffs, and seasonal volume. Use this as a planning baseline and confirm against the carrier's own lane time before committing to a date. #### Under-Keel Clearance Calculator URL: https://geratools.com/under-keel-clearance-calculator Calculate net under-keel clearance by subtracting static draft, squat, and heel allowance from charted depth corrected for tide height and water density. Built for port captains and navigators before entering shallow channels. How to use: 1. Enter charted depth and tide: Type the charted depth at the point from your nautical chart and the predicted tidal height above chart datum for your transit time. 2. Add draft and density: Enter the vessel's static deepest draft, the dock or sea water density, and the chart's reference density (usually 1.025 for salt water). 3. Read net UKC: The tool corrects depth for tide and density, subtracts draft, squat, and heel allowance, and shows the net clearance under your keel. FAQ: Q: What is under-keel clearance? A: Under-keel clearance is the vertical distance between the lowest point of a vessel's hull and the seabed. A positive value means the ship floats clear; a negative value means it would touch bottom. Q: Why does water density matter for draft? A: A ship floats deeper in less dense water. If you transit from salt water (1.025) into brackish or fresh water, the vessel sinks lower, reducing clearance. The tool applies a density correction to the effective draft. Q: What is squat and why subtract it? A: Squat is the bodily sinkage and trim a moving vessel experiences in shallow or confined water due to reduced pressure under the hull. It increases with speed and can be over a metre, so it must be reserved as clearance. Q: Is a fixed safety margin enough? A: No. Many ports require a minimum UKC of 10 to 15 percent of draft, or a fixed figure plus allowances for swell and uncertainty. Treat this tool as a planning aid and always follow your port's pilotage rules. Q: Does the calculator predict tide for me? A: No. You supply the predicted tidal height from an official tide table or prediction service. The tool then combines that height with charted depth, density, draft, squat, and heel to give net clearance. #### WMI Country & Manufacturer Lookup URL: https://geratools.com/wmi-country-lookup Looks up the ISO 3779 WMI (World Manufacturer Identifier) from the first three characters of a VIN against an embedded table of 200+ manufacturers. Shows country of manufacture, manufacturer name, and vehicle type entirely in your browser with no API call. How to use: 1. Enter a VIN or WMI: Type the full 17-character VIN or just the first three characters. The tool reads only the leading World Manufacturer Identifier. 2. Read the country and brand: The country of manufacture is decoded from characters 1-2, and the manufacturer plus vehicle type from the full three-character WMI. 3. Cross-check rare makes: If the manufacturer shows as unlisted, the country is still accurate. Confirm low-volume brands against an official VIN decoder. FAQ: Q: What is a WMI? A: The World Manufacturer Identifier is the first three characters of a VIN, assigned under ISO 3779 and ISO 3780. The first two characters encode the country and region, and all three together identify the specific manufacturer. Q: How is the country decoded? A: ISO 3780 assigns blocks of leading VIN characters to geographic regions. For example, codes starting with W are Germany, J is Japan, and 1, 4, and 5 are the United States. This tool matches your first two characters against those ranges. Q: Why are I, O, and Q never in a VIN? A: The letters I, O, and Q are excluded from every VIN position because they are too easily confused with the digits 1 and 0. The tool strips them automatically so a mistyped character is ignored. Q: Does a matching WMI mean the car was assembled in that country? A: It means the manufacturing plant that built the vehicle is registered in that country. A global brand may build the same model in several countries, each with its own WMI, so the country reflects the actual assembly plant. Q: Why is my manufacturer not listed? A: The embedded table covers the most common 200-plus WMIs. Rare, regional, or recently issued identifiers may not appear even though the country range still resolves correctly. Use an official decoder for niche brands. ### Sustainability & ESG #### AI Model Training Carbon Estimator URL: https://geratools.com/ai-model-carbon-estimator Enter your accelerator type, chip count, training hours, data-centre PUE, and grid carbon intensity to estimate training CO2e using the Strubell and Patterson methodology. Benchmarks the result against GPT-3 and BERT training footprints. For ML engineers and AI-ethics teams. Runs in your browser. How to use: 1. Choose your hardware: Pick an accelerator (A100, H100, V100, TPU v4, or custom) and enter how many chips you ran in parallel. 2. Enter run length and data centre: Type the wall-clock training time in hours, the data centre PUE, and your grid's carbon intensity in grams CO2e per kWh. 3. Read energy and emissions: The tool computes total kWh and CO2e, then benchmarks it against the published GPT-3 and BERT training footprints. FAQ: Q: What formula does this use? A: Energy in kWh equals chip power in kW times number of chips times hours times PUE. Emissions equal that energy times the grid carbon intensity. This mirrors the methodology in Strubell et al. (2019) and Patterson et al. (2021), which both multiply hardware power draw by run time, PUE, and grid intensity. Q: What is PUE and what value should I use? A: Power Usage Effectiveness is the ratio of total facility energy to the energy delivered to the IT equipment. A perfect data centre is 1.0; the global average is around 1.55, while best-in-class hyperscale facilities reach 1.1. Use your provider's reported figure if you have it. Q: Where do I get grid carbon intensity? A: Grid intensity is grams of CO2e per kWh and varies hugely by region and time. Coal-heavy grids exceed 600 g/kWh, the global average is around 480 g/kWh, and low-carbon grids like France, Sweden, or Quebec can be under 60 g/kWh. Tools like Electricity Maps publish live figures. Q: How accurate is the estimate? A: It is a first-order estimate. Real consumption depends on chip utilisation, memory and networking overhead, idle time, and embodied hardware emissions, none of which are captured here. Treat the number as an order-of-magnitude guide, not a certified figure for reporting. Q: Why benchmark against GPT-3 and BERT? A: Published estimates give a sense of scale: training GPT-3 is estimated at roughly 552 tonnes CO2e and the original BERT at roughly 0.65 tonnes (about the same as a few transatlantic flights). Comparing your run to these anchors makes an abstract kilogram figure intuitive. #### Climate Risk TCFD Screener URL: https://geratools.com/climate-risk-tcfd-screener Select your industry sector and geography to assess exposure to physical climate risks (acute and chronic) and transition risks (policy, technology, market, reputational) under 1.5°C and 4°C warming scenarios, producing a TCFD risk priority matrix. How to use: 1. Select your sector: Pick the industry sector that best matches your operations. Each sector carries a baseline transition-risk weighting based on emissions intensity. 2. Select your geography: Choose the region where your assets are concentrated. Geography drives the acute and chronic physical-risk exposure scores. 3. Read the risk matrix: The screener scores each TCFD risk category under both a 1.5°C and a 4°C scenario and ranks them so you can prioritise disclosure and mitigation. FAQ: Q: What is TCFD? A: The Task Force on Climate-related Financial Disclosures (TCFD) is a framework for reporting climate risk in financial filings. It splits risk into physical risks (from a changing climate) and transition risks (from moving to a low-carbon economy). Many jurisdictions now mandate TCFD-aligned reporting. Q: What is the difference between a 1.5°C and a 4°C scenario? A: A 1.5°C scenario assumes rapid decarbonisation, which raises transition risk (policy, carbon pricing, stranded assets) but limits physical risk. A 4°C scenario assumes little action, so physical risk (floods, heat, storms) dominates while transition pressure is lower. TCFD asks firms to test both. Q: Are these scores a formal risk assessment? A: No. This is an indicative screener to help you scope a TCFD disclosure and identify which risk categories deserve deeper, asset-level analysis. A full assessment needs site-specific hazard data and financial modelling. Q: What are acute versus chronic physical risks? A: Acute risks are event-driven — hurricanes, floods, wildfires. Chronic risks are gradual shifts — rising sea levels, sustained heat, changing rainfall and water stress. Both feed the physical-risk pillar of TCFD. Q: Is any data sent to a server? A: No. The scoring runs entirely in your browser using built-in reference weightings. Nothing you select is transmitted or stored anywhere. #### CO2 Production During Fermentation URL: https://geratools.com/co2-production-fermentation Calculates total CO2 produced as a beer or wine ferments from original gravity to final gravity, the residual dissolved CO2 at fermentation temperature, and the net CO2 available for natural carbonation. Runs 100% in your browser. How to use: 1. Enter original and final gravity: Type your starting (OG) and finishing (FG) specific gravity readings. The difference drives how much sugar was consumed and therefore how much CO2 was produced. 2. Set the batch volume and temperature: Enter the fermenter volume in litres and the fermentation temperature in Celsius. Temperature controls how much CO2 stays dissolved in the liquid. 3. Read the CO2 breakdown: The tool shows total CO2 mass produced, the residual dissolved CO2 in volumes, and the net CO2 vented or available for natural carbonation. FAQ: Q: How much CO2 does fermentation actually produce? A: Roughly 0.46 grams of CO2 per gram of sugar fermented, alongside an equal mass of ethanol. For a typical 20 litre batch dropping from 1.050 to 1.010, that is on the order of 200 to 230 grams of CO2. Q: What is residual dissolved CO2? A: Even after fermentation ends, the beer holds some CO2 in solution. The amount depends on temperature: colder liquid holds more. This residual level is expressed in volumes and is the starting point before you prime or force-carbonate. Q: Why does temperature matter for dissolved CO2? A: CO2 solubility falls as temperature rises. A beer fermented warm at 20C retains roughly 0.85 volumes of CO2, while one cold-conditioned near 2C retains close to 1.7 volumes. This residual is subtracted from your target carbonation. Q: Can I use this to size a closed pressure fermenter? A: It gives the total CO2 generated, which is the gas a sealed vessel must either hold under pressure or vent through a spunding valve. Combine the total mass with your vessel headspace to estimate pressure build, though exact pressure also depends on temperature and headspace volume. Q: Does the same formula apply to wine and cider? A: Yes. The 0.46 grams CO2 per gram sugar relationship comes from the fermentation stoichiometry and holds for any sugar fermented by yeast, so wine, cider, and mead all follow it. #### Embodied Carbon Calculator (Building Materials) URL: https://geratools.com/embodied-carbon-calculator Add quantities of common building materials by mass to compute embodied carbon in kg CO2e using ICE database v3.0 cradle-to-gate factors (lifecycle stages A1-A3). For architects, structural engineers, and sustainability consultants working toward RIBA 2030 embodied-carbon targets. How to use: 1. Add each material: For every material in the design — concrete, rebar, structural steel, timber, insulation, glass — pick it and enter the quantity in kilograms. 2. Let the tool apply ICE factors: Each quantity is multiplied by its cradle-to-gate embodied carbon factor (kg CO2e per kg) from the ICE database, covering lifecycle stages A1 to A3. 3. Read total embodied carbon: The tool sums every material, shows each one's contribution, and gives the total embodied carbon so you can compare design options against targets. FAQ: Q: What lifecycle stages does this cover? A: Stages A1 to A3 only — raw material supply, transport to the factory, and manufacturing. This cradle-to-gate boundary is the most common basis for early-design embodied-carbon comparison. It excludes construction (A4-A5), use (B), and end-of-life (C). Q: Where do the emission factors come from? A: From the Inventory of Carbon and Energy (ICE) database version 3.0 by Circular Ecology, a widely used UK reference for embodied carbon of construction materials, expressed in kg CO2e per kilogram of material. Q: Why does concrete dominate so many buildings? A: Concrete has a modest factor per kilogram, around 0.1 to 0.16, but buildings use enormous quantities of it, so it usually makes up the largest single share of structural embodied carbon. Cement production is the main driver; replacing some cement with GGBS or fly ash lowers it. Q: How does timber compare? A: Timber has a low cradle-to-gate factor — often well under 0.5 kg CO2e per kg — and also stores biogenic carbon while it stands, which some assessments credit separately. Substituting timber for steel or concrete in a frame can sharply cut embodied carbon, subject to structural and fire requirements. Q: How do I compare against RIBA 2030 targets? A: RIBA targets are expressed per square metre of floor area (for example under 625 kg CO2e per square metre for offices). Divide your total embodied carbon by the gross internal floor area to get the per-square-metre figure, then compare to the relevant target band. #### EU Carbon Removal Certification (CRCF) Eligibility Checker URL: https://geratools.com/eu-carbon-removal-certification Select a removal activity such as biochar, soil carbon, BECCS, blue carbon, enhanced weathering, or direct air capture to assess eligibility under EU Regulation 2024/3012 CRCF quality criteria and identify the certification route. For carbon project developers. How to use: 1. Select your activity: Choose your removal activity, such as direct air capture, BECCS, enhanced weathering, biochar, soil carbon, or blue carbon. The tool maps it to a CRCF activity family. 2. Affirm the quality criteria: Tick each of the four QU.A.L.ITY criteria your project meets: quantification, additionality, long-term storage, and sustainability. 3. Read the eligibility result: The tool shows the activity family, monitoring horizon, how many criteria are met, and whether the project is likely eligible for certification. FAQ: Q: What are the CRCF quality criteria? A: Regulation (EU) 2024/3012 sets four overarching QU.A.L.ITY criteria: quantification of a net removal benefit, additionality beyond baseline and legal requirements, long-term storage with monitoring and reversal liability, and sustainability that does no significant harm and delivers co-benefits. All four must be met. Q: Does biochar count as permanent removal? A: Under the CRCF, biochar applied to soil is classed as carbon storage in products, requiring durable storage of at least 35 years. It is distinct from permanent geological removals like DACCS or BECCS, which target storage of several centuries or more. Q: What is the difference between carbon farming and permanent removal? A: Carbon farming covers temporary or medium-term storage in soils and biomass, such as soil carbon and blue carbon, monitored over the activity period of at least five years per cycle. Permanent removal targets centuries-long storage and is subject to stricter reversal liability. Q: How is a project actually certified? A: Once the quality criteria are met using the activity-specific methodology adopted by delegated act, certification is carried out by an accredited certification body operating under a certification scheme recognised by the Commission. This tool only indicates likely eligibility. Q: Is this regulatory advice? A: No. It is an indicative checker based on the published regulation. Activity-specific methodologies are still being adopted via delegated acts, so confirm details with an approved CRCF certification scheme before relying on the result. #### Fermentation CO2 Airlock Bubble Rate Interpreter URL: https://geratools.com/fermentation-co2-airlock-activity Count airlock bubbles over a fixed window to estimate bubbles per minute and the likely fermentation phase — lag, exponential, stationary, or decline. Built for homebrewers deciding when to take gravity readings. Includes the key caveat that bubbles indicate activity, not gravity. Runs in your browser. How to use: 1. Count the bubbles: Watch the airlock and count how many bubbles pass over a fixed time, such as 60 seconds. 2. Enter the count and window: Type the number of bubbles and the number of seconds you counted over. 3. Read the phase: The tool converts to bubbles per minute and suggests the likely fermentation phase plus what to do next. FAQ: Q: How many airlock bubbles per minute is normal? A: During vigorous fermentation a typical 5-gallon ale can bubble 30–60+ times per minute. Early lag and late decline phases produce only a few bubbles per minute, and a finished or stuck batch produces none. Q: Can I tell if fermentation is done from the airlock? A: No — the airlock only shows CO2 activity, not sugar content. Bubbling can slow or stop while fermentation continues, or continue from CO2 off-gassing after it ends. Always confirm with a stable hydrometer reading over two to three days. Q: My airlock isn't bubbling, is fermentation stuck? A: Not necessarily. A loose lid, a leaky grommet, or a large headspace can let CO2 escape without bubbling. Check the seal and take a gravity reading before assuming the yeast has stalled. Q: Why does bubble rate vary so much between batches? A: Bubble rate depends on vessel headspace, seal quality, temperature, batch size, and yeast strain — not just fermentation vigour. That is why the same true fermentation rate can look very different across two fermenters. Q: When should I take a gravity reading? A: When the bubble rate has dropped to a few per minute or stopped, give it a day or two then measure gravity. If the reading is stable across two to three days, fermentation is complete. #### F-Gas Quota & HFC Phase-Down Calculator URL: https://geratools.com/fgas-calculator Enter a refrigerant (R-410A, R-32, R-404A, R-134a and more) and quantity in kilograms to compute the CO2-equivalent in tonnes using each blend's GWP, see where it sits in the EU HFC phase-down schedule, and flag pre-charged-equipment and service-ban restrictions for HVAC and refrigerant trades. How to use: 1. Select the refrigerant: Pick the gas or blend from the list; each carries its official Global Warming Potential (GWP) used across the EU F-Gas Regulation. 2. Enter the quantity in kilograms: Type the charge or quantity in kg; the tool multiplies it by the GWP to give the CO2-equivalent in tonnes (tCO2e). 3. Read the CO2e and restrictions: See the tCO2e total, the equipment leak-check threshold band it falls into, and any phase-down or service-ban flags for high-GWP gases. FAQ: Q: How is CO2-equivalent calculated for a refrigerant? A: CO2-equivalent in tonnes equals the mass in kilograms multiplied by the gas's Global Warming Potential, divided by 1,000. For example 10 kg of R-404A (GWP 3,922) is 10 x 3922 / 1000 = 39.22 tonnes CO2e. The GWP is fixed per gas in the EU F-Gas Regulation. Q: What is the HFC phase-down? A: The EU F-Gas Regulation caps the total CO2-equivalent tonnes of HFCs placed on the market each year and ratchets that cap down over time toward near-elimination by 2050. Because the cap is measured in CO2e, high-GWP gases consume quota far faster than low-GWP alternatives like R-32 or R-1234yf. Q: What are the leak-check thresholds? A: Stationary equipment must be leak-checked at intervals set by its charge in CO2e: at least every 12 months from 5 tonnes, every 6 months from 50 tonnes, and every 3 months from 500 tonnes, with the intervals doubling where a leak-detection system is fitted. The tool shows which band your charge falls into. Q: Are there bans on high-GWP refrigerants? A: Yes. Servicing of refrigeration equipment with refrigerants of GWP 2,500 or above (such as R-404A) using virgin gas is restricted, and many new equipment types face GWP placing-on-the-market bans. The tool flags refrigerants over the 2,500 GWP threshold so you can plan retrofits. Q: Does this tool send my figures anywhere? A: No. The refrigerant and quantity are multiplied locally in your browser. Nothing about your equipment, charge or business is uploaded, logged or stored on any server. #### Nature-Positive Risk Screener (TNFD) URL: https://geratools.com/nature-positive-risk-screener Walk through a simplified TNFD LEAP screen — Locate, Evaluate, Assess, Prepare — to identify which business activities have material dependencies on ecosystem services and nature-related risks, producing a prioritised list for detailed TNFD disclosure. For sustainability officers. How to use: 1. Describe the activity's location: Indicate whether the activity operates in or near a sensitive location such as a protected area, water-stressed basin, or biodiversity hotspot. 2. Rate dependencies and impacts: Score how much the activity depends on ecosystem services (water, pollination, climate regulation) and how much it impacts nature (land use, pollution, water use). 3. Read the priority rating: The tool combines location sensitivity, dependency, and impact into a materiality rating that tells you whether the activity needs detailed TNFD assessment. FAQ: Q: What is the TNFD LEAP approach? A: LEAP stands for Locate, Evaluate, Assess, and Prepare. It is the Taskforce on Nature-related Financial Disclosures recommended process for organisations to identify and assess their nature-related dependencies, impacts, risks, and opportunities before disclosing them. Q: What is the difference between a dependency and an impact? A: A dependency is how much your activity relies on nature to function, such as needing fresh water or pollination. An impact is how your activity changes nature, such as converting land or discharging pollutants. Both create financial risk and both must be screened. Q: Why does location matter so much? A: The same activity can be low-risk in one place and high-risk in another. Operating in or near a protected area, a water-stressed basin, or a biodiversity hotspot sharply raises the materiality of any dependency or impact, which is why Locate is the first LEAP step. Q: What are ecosystem services? A: Ecosystem services are the benefits nature provides that businesses rely on — provisioning services like water and timber, regulating services like flood control and pollination, and supporting services like soil formation. Losing them creates operational and financial risk. Q: Does a high score require disclosure? A: A high materiality rating flags an activity for detailed TNFD assessment and likely disclosure, but the formal requirement depends on your reporting framework and jurisdiction. Use the rating to prioritise where to spend assessment effort, then confirm disclosure obligations with your advisers. #### Packaging Carbon Footprint Calculator URL: https://geratools.com/packaging-carbon-calculator Add packaging components by material, weight in grams, and recycled content percentage, then multiply by annual volume to compute total CO2e using DEFRA conversion factors. Supports multi-material composite packs for brand owners, packaging engineers, and sustainability teams. How to use: 1. Add each packaging component: For every material in the pack — bottle, label, cap, carton — pick the material, enter its weight in grams, and the recycled content percentage. 2. Set the annual volume: Enter how many units of this pack you produce or place on the market each year so the per-unit footprint scales to a yearly total. 3. Read per-unit and annual CO2e: The tool sums every component into a per-unit footprint, applies the recycled-content discount, and multiplies by volume for the annual figure. FAQ: Q: Which emission factors does this use? A: It uses DEFRA UK Government greenhouse gas conversion factors for materials production, expressed in kg CO2e per kg of material. Virgin and recycled grades have separate factors, and the tool blends them by your recycled content percentage. Q: How does recycled content reduce the footprint? A: Recycled material avoids most of the energy-intensive primary production step. The tool blends the virgin and recycled factors in proportion to your recycled content, so 50 percent recycled PET sits halfway between the virgin and fully recycled values. Q: Can I model a multi-material pack? A: Yes. Add one row per component — for example a glass bottle, an aluminium cap, and a paper label — and the tool totals them. This is essential because the lightest component by weight can still dominate if it is a high-impact material like aluminium. Q: Why is aluminium so high per kilogram? A: Primary aluminium smelting is extremely energy intensive, around 9 to 12 kg CO2e per kg for virgin metal. Recycled aluminium is far lower, near 0.5 kg CO2e per kg, which is why high recycled content is the single biggest lever for metal packaging. Q: Does this include transport or end-of-life? A: No. This covers cradle-to-gate material production only. Transport to your site, filling, distribution, and disposal or recycling at end of life are separate stages. For a full lifecycle assessment, add those stages on top of this material footprint. #### REACH / RoHS Substance Checker URL: https://geratools.com/reach-rohs-checker Free REACH and RoHS substance checker. Select material types and whether your article is electrical to flag likely SVHCs under REACH and restricted hazardous substances under RoHS 2011/65/EU, plus SCIP notification and supplier-communication duties. How to use: 1. Select your materials: Choose the material types present in your product, such as soldered electronics, PVC plastics, painted metal or treated leather. 2. Confirm if it is electrical: Indicate whether the product is electrical or electronic equipment, which determines whether RoHS applies. 3. Review the flagged obligations: The tool lists likely SVHC concerns under REACH and applicable RoHS limits, plus SCIP and supplier-communication duties. FAQ: Q: What is the difference between REACH and RoHS? A: REACH governs chemicals in all articles sold in the EU, focusing on Substances of Very High Concern (SVHCs) on the Candidate List. RoHS restricts ten specific hazardous substances in electrical and electronic equipment. A product can be subject to both at once. Q: What is the 0.1% SVHC threshold? A: Under REACH, if an article contains a Candidate List SVHC above 0.1% weight by weight, the supplier must communicate safe-use information down the supply chain and, since 2021, submit a SCIP notification to the ECHA database. Q: What are the RoHS substance limits? A: RoHS restricts lead, mercury, hexavalent chromium, PBB and PBDE flame retardants, and four phthalates (DEHP, BBP, DBP, DIBP) to 0.1% by weight in homogeneous materials, and cadmium to 0.01%, unless an exemption applies. Q: What is a SCIP notification? A: SCIP is the ECHA database of Substances of Concern In articles as such or in complex objects (Products). Companies placing articles containing SVHCs above 0.1% on the EU market must notify ECHA so waste operators and consumers can access the data. Q: Is my product data sent anywhere? A: No. The checker uses a built-in mapping of materials to common substance concerns and runs entirely in your browser. No material or product detail is transmitted or stored. #### ReFi Tokenised Carbon Credit Equivalence Calculator URL: https://geratools.com/refi-tokenised-credit-calculator Enter project type, vintage, Verra or Gold Standard methodology, OTC market price, and tonnes to compute the expected price range, on-chain retirement cost via Toucan-style carbon pools, and the total cost differential versus a registry retirement. How to use: 1. Describe the credit: Select project type, vintage year, and registry methodology so the tool can apply a realistic price multiplier to your entered OTC base price. 2. Enter market price and quantity: Type the current over-the-counter price per tonne and the number of tonnes you want to retire, then add the on-chain pool premium and gas estimate. 3. Compare the two routes: The tool shows the registry retirement cost and the tokenised retirement cost side by side, then the per-tonne and total differential so you can pick the cheaper path. FAQ: Q: Why do tokenised credits sometimes trade at a different price? A: Tokenised credits are bridged into on-chain carbon pools like BCT or NCT, which set a pool floor price. Generic, older, or lower-quality vintages often clear near that floor, while premium nature-based or recent vintages can trade above it, creating a price gap versus the OTC spot. Q: What is the difference between retiring on a registry and retiring on-chain? A: Registry retirement permanently cancels the credit in the issuing registry such as Verra. On-chain retirement burns a tokenised version (for example via Toucan) and records the retirement on a public blockchain, which gives an immutable, instantly verifiable proof but adds bridge, pool, and gas costs. Q: Does this tool fetch live prices? A: No. You enter the current OTC price yourself from your broker or a market data source. The tool then applies methodology and vintage multipliers and adds your pool premium and gas estimate so you can model the comparison without any live API. Q: What is a carbon pool premium? A: When credits are deposited into a pool token you may pay a small premium or fee over the underlying credit price for the liquidity and standardisation the pool provides. Typical premiums range from a few percent to around ten percent depending on the pool and credit quality. Q: Are older vintages worth less? A: Generally yes. Buyers and pools often discount pre-2018 vintages because methodologies and additionality scrutiny have tightened. The tool applies a vintage discount so older credits show a lower expected clearing price than recent issuances. #### Right-to-Repair Product Scorer URL: https://geratools.com/right-to-repair-scorer Assess a product against the EU Ecodesign repairability criteria — spare-parts availability, repair documentation, disassembly with common tools, and software/support duration. Produces a weighted repairability score out of 100 and flags gaps. For product designers and compliance engineers. How to use: 1. Rate each repairability factor: Score spare-parts availability, documentation, ease of disassembly, tool requirements, and software support, each on a 0 to 10 scale. 2. Adjust the weights if needed: Each factor carries a default weight reflecting its importance in the Ecodesign criteria; you can keep the defaults or tune them. 3. Read your repairability score: The tool computes a weighted score out of 100, assigns a band, and lists the lowest-scoring factors to address first. FAQ: Q: What does the right-to-repair score measure? A: It measures how easily a product can be repaired across the factors regulators focus on: whether spare parts are available and affordable, whether repair instructions are published, how deeply the device must be disassembled to reach common failures, whether ordinary tools suffice, and how long software and security updates are provided. Q: How is the weighted score calculated? A: Each factor is rated 0 to 10 and multiplied by its weight. The weighted ratings are summed and divided by the sum of the weights, then scaled to a 0 to 100 index. This mirrors the approach of repairability indices, where the most impactful factors, such as spare-parts and disassembly, carry the largest weight. Q: Which laws does this relate to? A: It reflects the EU Ecodesign for Sustainable Products framework and product-specific Ecodesign regulations that mandate spare-parts availability and repair information for goods such as appliances, displays, and electronics, along with the EU Right to Repair Directive and comparable UK measures. National details vary by product group. Q: What software-support duration should I aim for? A: Longer is better and increasingly mandated. Regulators are pushing minimum security-update periods measured in years beyond the last unit sold. A device whose hardware is repairable but is bricked by an end of software support has poor real-world longevity, which is why software is a scored factor here. Q: Is the score an official repairability index? A: No. It is an internal design and triage aid that approximates the regulatory factors. The official French repairability/durability indices and any product-specific Ecodesign scoring use prescribed sub-criteria and formulas. Use this to compare design options early, then validate against the binding methodology. #### Scope 2 Market-Based vs Location-Based Emissions Comparator URL: https://geratools.com/scope2-market-vs-location-based Enter electricity consumption, grid emission factor, the volume and emission factor of your energy attribute certificates (REGO/GO/REC), and the residual mix factor to compute and compare Scope 2 under both GHG Protocol methods, highlighting the EAC coverage gap. How to use: 1. Enter your electricity use: Type total annual electricity consumption in kWh and the grid average emission factor for your country in kg CO2e per kWh. 2. Add your certificates: Enter the kWh covered by energy attribute certificates, their emission factor (usually zero for renewables), and the residual mix factor for the uncovered remainder. 3. Compare both methods: The tool computes location-based and market-based totals side by side, shows the EAC coverage percentage, and quantifies the gap you can close with more certificates. FAQ: Q: What is the difference between the two methods? A: The location-based method uses the average grid emission factor for the region, regardless of any contracts. The market-based method reflects the emissions of the specific electricity you chose to purchase, using energy attribute certificates and supplier-specific or residual-mix factors. Q: Why does the GHG Protocol require both numbers? A: The Scope 2 Guidance mandates dual reporting so that stakeholders see both the physical grid reality of where you consume power and the contractual choices you made. Reporting only the lower market-based figure without the location-based one is not compliant. Q: What is a residual mix factor? A: It is the emission factor of the electricity left on the grid after all certificates have been claimed by others. You apply it to the portion of your consumption not covered by your own certificates, so you do not double-count renewables already claimed elsewhere. Q: What counts as an energy attribute certificate? A: REGOs in the UK, Guarantees of Origin (GOs) in the EU, and RECs in North America are the main instruments. Each certificate represents the attributes of one MWh of generation and lets you claim that electricity under the market-based method. Q: What does the coverage gap tell me? A: The gap is the consumption not yet matched by certificates, valued at the residual mix factor. It shows the emissions you could still eliminate from your market-based figure by procuring certificates or a power purchase agreement for the remaining volume. #### Tree Equivalent Carbon Calculator URL: https://geratools.com/tree-equivalent-calculator Enter a CO2e figure in kg or tonnes, choose a tree species and the number of years, and the tool computes how many trees are needed to absorb it using average sequestration rates. A clear communication tool for sustainability reports and offset messaging. How to use: 1. Enter your CO2e amount: Type the emissions figure and pick whether it is in kilograms or tonnes of CO2e. 2. Choose species and timeframe: Select a tree type and the number of years you want the absorption spread over. Slower-growing trees need longer. 3. Read the tree count: The tool divides total CO2e by each tree's lifetime absorption over your chosen period to give the number of trees needed. FAQ: Q: How much CO2 does one tree absorb? A: It varies hugely by species, age, climate, and management, but a common planning figure is around 21 kg CO2 per mature tree per year, or roughly 0.5 to 1 tonne over a 40-year life. Young trees absorb little; the peak comes in their middle decades. Q: Why does the timeframe matter? A: Trees absorb carbon gradually over decades, not instantly. Spreading the same emissions over 10 years needs more trees than over 40 years, because each tree has fewer years to do its work in the shorter window. Q: Is planting trees a valid offset? A: Tree planting can help but is not a like-for-like cancellation of fossil emissions. Carbon stored in trees can be released by fire, disease, or felling, and the absorption takes decades. Reducing emissions at source is always the priority. Q: Which species absorbs the most? A: Fast-growing broadleaf species like oak and beech in temperate climates, and many tropical species, sequester more per tree than slow conifers or small ornamentals. The tool uses representative average rates, so treat the species choice as indicative. Q: Should I use this for compliance claims? A: No. It is a communication aid to make a CO2e figure tangible. Verified offsetting requires accredited projects with measured, additional, and permanent sequestration — not a back-of-envelope tree count. ### Legal & Regulatory #### ADA / Section 508 Accessibility Checklist URL: https://geratools.com/ada-section-508-checklist Step through WCAG 2.1 Level A and AA success criteria mapped to ADA Title III and Section 508 requirements for web, mobile, and documents. Mark each pass, fail, or N/A and get a prioritised remediation list with a conformance score. For US contractors and businesses. How to use: 1. Review each criterion: Read each WCAG 2.1 A/AA success criterion and decide whether your product passes, fails, or it does not apply. 2. Mark the status: Set each item to Pass, Fail, or N/A; failures feed the prioritised remediation list. 3. Read the conformance score: The tool excludes N/A items, computes the share of applicable criteria you pass, and lists the failed criteria grouped by severity. FAQ: Q: How do the ADA and Section 508 relate to WCAG? A: Section 508 of the Rehabilitation Act explicitly adopts WCAG 2.0 Level AA (with later updates moving toward 2.1) as its technical standard for federal ICT. The ADA does not name a version in statute, but courts and the Department of Justice consistently treat WCAG 2.1 Level AA as the practical benchmark for Title III web accessibility. Q: What is the difference between Level A and Level AA? A: WCAG defines three conformance levels. Level A is the minimum and covers the most fundamental barriers, such as text alternatives and keyboard access. Level AA adds stricter requirements like 4.5:1 contrast, captions, and resize support. Both ADA practice and Section 508 require meeting Level A and AA together. Q: How is the conformance score calculated? A: The tool counts only the criteria you mark as applicable, ignoring any set to N/A. The score is the number of Pass items divided by the number of applicable items, expressed as a percentage. A single failed Level A criterion is still a real barrier even if the overall percentage looks high. Q: Does passing every item here guarantee legal compliance? A: No. This is a structured self-assessment, not an audit. Real conformance requires testing with assistive technology, manual review by trained evaluators, and often a formal Accessibility Conformance Report (VPAT). Treat failures here as confirmed gaps and passes as candidates for verification. Q: Does this cover documents and mobile, not just web? A: The WCAG success criteria apply across web pages, web applications, mobile apps, and electronic documents such as PDFs. The same criteria — text alternatives, contrast, keyboard operation, and so on — are interpreted for each platform, so use this checklist for any digital deliverable in scope. #### Commercial Lease Rent Escalation Calculator URL: https://geratools.com/commercial-lease-rent-escalation-calculator Calculates year-by-year base rent with fixed-percentage or CPI-style escalations plus total lease cost over the term for office, retail, or industrial space. Tenants, landlords, and brokers use it to compare leases and budget occupancy cost. How to use: 1. Enter the starting rent and term: Type the first-year base rent and the lease length in years for the space you are evaluating. 2. Set the escalation: Enter the annual escalation rate and choose whether it compounds each year, which is typical for CPI and fixed-percentage clauses. 3. Read the projection: The tool shows each year's rent and the cumulative total cost over the full lease term so you can compare options. FAQ: Q: What is the difference between fixed and CPI escalation? A: A fixed escalation raises rent by a set percentage each year regardless of inflation. A CPI escalation ties the increase to the Consumer Price Index, so the percentage varies with actual inflation. Both compound on the prior year's rent; this tool lets you model an assumed percentage for either. Q: Why does compounding matter so much? A: A 3 percent annual bump compounds, so by year ten the rent is about 30 percent above year one, not 27 percent from simple addition. Over a long term the compounded total can be tens of thousands more than a naive estimate, which is why projecting the full schedule is important. Q: Should I model this on total rent or per square foot? A: Either works as long as you are consistent. Enter the annual base rent or the annual rent per square foot times the area as the starting rent. The escalation percentage and term apply the same way and the total reflects whichever basis you entered. Q: Does this include operating expenses or CAM? A: No. This projects base rent only. Triple-net leases add common-area maintenance, taxes, and insurance that also tend to rise. Add those separately to get a full occupancy-cost picture, since they are often passed through without a cap. Q: How do I compare two leases with different escalations? A: Run each lease through the calculator and compare the total lease cost over the same term. A lower starting rent with a steeper escalation can end up costing more than a higher starting rent with a flat bump, which only the full projection reveals. #### Environmental Permit Requirement Checker (UK/EU) URL: https://geratools.com/environmental-permit-checker Answer questions about activity type (waste management, combustion plant, industrial emissions, water discharge, solvent use) and scale to estimate UK Environmental Permitting Regulations or EU Industrial Emissions Directive obligations, the likely permit tier (exempt, standard rules, or bespoke), and indicative regulator charges. Runs in your browser. How to use: 1. Pick the activity: Select the type of regulated activity — waste, combustion, industrial process, water discharge, or solvent use. 2. Enter the scale: Provide the relevant capacity figure (tonnes of waste, MW thermal input, or discharge volume) so the tool can apply the regulatory thresholds. 3. Read the likely tier: The checker estimates whether you are exempt, can use a standard-rules permit, or need a bespoke permit, and notes the indicative charge band. FAQ: Q: What law requires environmental permits in England and Wales? A: The Environmental Permitting (England and Wales) Regulations 2016 (EPR) consolidate permitting for waste operations, water discharges, installations, and mining-waste activities. Larger industrial installations are also driven by the EU Industrial Emissions Directive, which the EPR implements domestically. Scotland and Northern Ireland have parallel regimes. Q: What is the difference between standard rules and bespoke permits? A: A standard rules permit is a pre-set, lower-cost permit for common, lower-risk activities that fit a published rule set — it is quicker and cheaper to obtain. A bespoke permit is tailored to your specific site and is needed when your activity falls outside any standard rule set, is larger, or poses site-specific risks. Q: When can I use a waste exemption instead of a permit? A: Some low-risk waste activities can be registered as exemptions rather than fully permitted, for example storing or treating small quantities of specific waste types. Exemptions still require registration with the regulator and have strict limits on waste type and tonnage; exceed those and you need a permit. Q: What capacity makes a combustion plant a permitted installation? A: Combustion plant with a total rated thermal input of 50 MW or more is a Chapter II installation under the Industrial Emissions Directive and needs a bespoke installation permit. Medium combustion plant between 1 MW and 50 MW falls under the Medium Combustion Plant Directive and needs a permit, while smaller units may be exempt. Q: Is this a substitute for advice from the regulator? A: No. This is an indicative triage tool. The exact permit you need depends on detailed definitions, waste codes, location (such as proximity to protected sites), and emissions. Always confirm with the Environment Agency, SEPA, NRW, or NIEA, and check current charging schemes before applying. #### LLC Dissolution Asset Distribution Calculator URL: https://geratools.com/llc-dissolution-asset-distribution-calculator Subtracts wind-up costs and outstanding liabilities from liquidated asset proceeds, then distributes remaining cash to members by capital-account balance. Business attorneys and accountants use it when winding up an LLC. How to use: 1. Enter proceeds and costs: Type the cash from liquidated assets, the total outstanding liabilities, and the wind-up and liquidation costs. 2. Add each member's capital account: Enter each member's positive capital-account balance, which sets the order and proportion of the final cash distribution. 3. Read the distributions: The tool pays creditors and costs first, then distributes any remaining cash to members in proportion to their capital accounts. FAQ: Q: What order are payments made in a dissolution? A: Under the typical statutory and operating-agreement waterfall, creditors are paid first, including members who are creditors, then wind-up and liquidation costs, then members receive liquidating distributions according to their positive capital-account balances. This tool follows that order. Q: Why distribute by capital account rather than ownership percentage? A: Most operating agreements and the default LLC rules liquidate according to positive capital-account balances, which reflect each member's contributions, allocated profits and losses, and prior distributions. Ownership percentage alone can misstate what each member is actually owed at wind-up. Q: What happens if liabilities exceed asset proceeds? A: Then there is nothing left to distribute and members may face capital calls or, depending on the entity and guarantees, personal exposure to the extent of any deficits. The tool shows a zero distribution and flags the shortfall so you can plan for it. Q: Does this handle a deficit capital account? A: This calculator distributes positive remaining cash by positive capital balances. A member with a deficit capital account may owe a restoration depending on the operating agreement; that is a legal determination outside this estimate. Enter only positive balances for the distribution split. Q: Is this a substitute for legal or tax advice? A: No. Dissolution involves state filings, creditor notice, tax clearance, and final K-1s. Use this tool to model the cash split, then have a business attorney and accountant finalise the wind-up. #### SCC Transfer Impact Assessment Tool URL: https://geratools.com/scc-transfer-impact-assessment Enter the destination country and data type to generate a Transfer Impact Assessment scorecard aligned with the EDPB's six-step methodology and the Schrems II ruling. Flags surveillance and rule-of-law risk and recommends the supplementary technical measures needed before relying on SCCs. How to use: 1. Pick the destination and adequacy status: Choose the country the data is transferred to; the tool knows whether it benefits from an EU adequacy decision and, if so, exits early. 2. Describe the data and the importer: Select the sensitivity of the data, whether it is encrypted in transit and at rest, and whether the importer can access plaintext, so the surveillance exposure can be weighed. 3. Read the risk score and measures: The scorecard returns a low/medium/high risk band with the specific supplementary technical, contractual and organisational measures you should apply before relying on SCCs. FAQ: Q: What is a Transfer Impact Assessment? A: A TIA is the documented risk assessment the Schrems II ruling and the EDPB require before you rely on Standard Contractual Clauses to send personal data outside the EEA. It checks whether the destination country's laws undermine the SCC protections and, if so, what extra measures restore an essentially equivalent level of protection. Q: When do I not need a TIA? A: If the destination has an EU adequacy decision — such as the UK, Switzerland, Japan, or the US under the Data Privacy Framework for certified importers — the transfer is treated like an intra-EEA transfer and no SCCs or TIA are required. The tool detects adequacy and tells you when you can stop. Q: What are supplementary measures? A: They are the technical, contractual and organisational controls the EDPB recommends adding on top of SCCs when local law poses a risk. The strongest is technical: end-to-end or strong at-rest encryption where the importer never holds the keys, which can make surveillance access ineffective even if a government demands the data. Q: Does this replace legal advice? A: No. The tool gives a structured, repeatable first-pass scorecard so legal counsel can focus on the genuinely high-risk transfers. The final assessment and the decision to proceed should always be reviewed by a qualified data protection lawyer or your DPO. Q: Is anything I enter sent to a server? A: No. The country, data type and encryption answers are evaluated entirely in your browser. Nothing about your transfers is uploaded, which is exactly what you want when assessing sensitive cross-border data flows. #### SOC 2 Readiness Checker URL: https://geratools.com/soc2-readiness-checker Score your organisation against the five SOC 2 Trust Service Criteria — security, availability, confidentiality, processing integrity, and privacy — using control prompts grouped by category, and get a colour-coded gap heat-map so startups can prioritise remediation before a Type I or Type II audit. How to use: 1. Choose your criteria scope: Security is mandatory; toggle on availability, confidentiality, processing integrity and privacy if they are in scope for your report. 2. Answer the control prompts: Mark each control as in place, partial or missing across access control, change management, monitoring, vendor risk and the other categories. 3. Read the gap heat-map: See a per-criterion readiness percentage and a colour-coded heat-map highlighting the weakest categories to remediate before booking your audit. FAQ: Q: What are the five SOC 2 Trust Service Criteria? A: Security (the only mandatory one, also called the Common Criteria), availability, confidentiality, processing integrity, and privacy. You choose which to include based on what matters to your customers, but every SOC 2 report must include security as its foundation. Q: What is the difference between Type I and Type II? A: A Type I report assesses whether your controls are suitably designed at a single point in time. A Type II report tests whether those controls operated effectively over a period, typically three to twelve months. Type II carries far more weight with enterprise buyers but requires evidence collected throughout the window. Q: How does the readiness score work? A: Each control you mark as in place scores full points, partial controls score half, and missing controls score zero. The tool averages these within each criterion to give a percentage, then flags categories below a healthy threshold so you know where remediation effort will move the needle most. Q: Do we need all five criteria? A: No. Security is required, and you add the others only where relevant. A SaaS handling customer uptime commitments often adds availability; one processing regulated data adds confidentiality and privacy. Scoping in criteria you cannot evidence only adds audit cost and risk. Q: Is my assessment data uploaded? A: No. Every answer and the resulting heat-map are computed in your browser. Nothing about your controls, gaps or organisation is sent to a server, logged or stored, so you can run an honest internal assessment without exposure. #### Spousal Support / Alimony Calculator URL: https://geratools.com/spousal-support-alimony-calculator Estimate spousal support amount and duration from the income gap, marriage length, and standard-of-living factors. Models common guideline formulas — a percentage of the income differential for the amount and a length-of-marriage multiplier for duration. How to use: 1. Enter both gross monthly incomes: Type the higher earner's and lower earner's gross monthly incomes. The difference drives the support amount under the differential formula. 2. Set the marriage length: Enter the number of years married. Duration formulas multiply marriage length by a factor that rises in longer marriages. 3. Read the estimated amount and term: The tool shows a monthly support estimate, a likely duration band, and the resulting recipient income after support. FAQ: Q: How is the alimony amount estimated? A: A widely used guideline takes a percentage of the higher earner's income and subtracts a smaller percentage of the lower earner's income — the classic 30%/20% differential. The result is capped so the recipient's total income does not exceed a set share (commonly 40%) of the parties' combined income. Q: How is the duration of support estimated? A: Many jurisdictions tie duration to marriage length: a fraction of the years married, increasing in long marriages, with marriages over roughly twenty years sometimes treated as indefinite or until retirement. This tool applies a stepped multiplier as an illustration. Q: Are these the official numbers for my state? A: No. Only a handful of states publish formulaic guidelines, and many use the open-ended statutory factors instead — need, ability to pay, age, health, and standard of living. Treat the output as a negotiation anchor, not a court order. Q: Does this account for taxes or child support? A: No. Since 2019, federal alimony is neither deductible nor taxable for new orders, and child support is calculated separately and usually takes priority. Model child support first, then revisit spousal support against the remaining income. Q: What is the 40% combined-income cap? A: Several guideline formulas prevent the recipient's post-support income from exceeding about 40% of the couple's combined income, so the higher earner never ends up worse off than the recipient. This tool applies that cap and tells you when it binds. #### Uganda NIN Validator & Decoder — Class, Gender & Birth Year URL: https://geratools.com/uganda-nin-validator Free Uganda NIN validator. Check the 14-character alphanumeric format of a Ugandan National Identification Number (NIRA) and decode the documented class, gender and birth-year digits — entirely in your browser. Privacy-first, no network requests, nothing is sent anywhere. How to use: 1. Enter the NIN: Type or paste the 14-character alphanumeric NIN. It is upper-cased automatically. 2. Read the breakdown: The tool validates the 14-character format and decodes the documented applicant class, gender code and the last two digits of the year of birth. FAQ: Q: What does a Uganda NIN encode? A: The NIRA NIN is 14 alphanumeric characters. By documented convention the first character is the applicant class (C = citizen), the second is the gender code (M or F), the third and fourth are the last two digits of the year of birth, and the remainder is a NIRA-assigned serial. Q: Why is the serial not verified? A: NIRA does not publish a check-digit algorithm, so this tool validates the 14-character alphanumeric format and the documented class, gender and birth-year prefix but cannot verify the serial. Q: Is my NIN sent anywhere? A: No. The validator is privacy-first. All processing happens locally in your browser with no network requests — your NIN never leaves your device and is never checked against the NIRA database. Q: How long is a Uganda NIN? A: Exactly 14 characters. Unlike many national IDs it is alphanumeric, mixing letters and digits, so it cannot be validated as a purely numeric string. Q: What does the C at the start of a NIN mean? A: The first character is the applicant class. C marks a Ugandan citizen, which is the common case on a National ID card; F is used for some foreign or non-citizen records. Any other first character is unrecognised. Q: Can I tell someone's age from their NIN? A: Only approximately. Positions 3 and 4 hold the last two digits of the year of birth, so a NIN whose third and fourth characters are 90 indicates a birth year ending in 90 — but the day, month and century are not encoded. Q: What is the difference between a NIN and a National ID card number? A: The NIN is the permanent 14-character identity number tied to the person and printed on the card. The card itself also carries a separate document number that changes on reissue. This tool decodes the NIN. Q: Why can't the tool tell me if a NIN is real? A: NIRA does not publish a check-digit algorithm and does not offer a public lookup. The tool can confirm the format and the documented class, gender and birth-year prefix, but only NIRA can confirm a NIN was actually issued. #### Saudi Iqama & National ID Validator URL: https://geratools.com/saudi-iqama-validator Free Saudi national ID and Iqama validator. Check a 10-digit Saudi ID or Iqama number with the official Saudi check-digit algorithm and read whether it is a citizen ID (1) or a resident Iqama (2). Privacy-first and runs entirely in your browser — nothing is sent anywhere. How to use: 1. Enter the number: Type or paste the 10-digit Saudi national ID or Iqama number. 2. Read the identity type: The first digit is shown — 1 means a Saudi citizen ID and 2 means a resident Iqama. 3. Check validity: The tool recomputes the Saudi check digit and tells you whether the number passes. FAQ: Q: What check-digit algorithm does this use? A: It uses the official Saudi Luhn-style algorithm — doubling the digits in odd positions (reducing two-digit results), summing with the even-position digits, then taking (10 minus the sum mod 10) mod 10 as the expected last digit. Q: How accurate is the result? A: A passing check digit confirms the number is mathematically well-formed and starts with 1 or 2, but it cannot confirm the number is registered or active in Absher or any government system. Q: Is my ID number sent anywhere? A: No. The validator is privacy-first — all processing happens locally in your browser and the number never leaves your device. Q: How do I tell a Saudi national ID from an Iqama? A: Read the first digit. A 1 means a Saudi citizen national ID (Hawiya), while a 2 means a resident foreigner's Iqama. Both are 10 digits long. Q: How many digits is a Saudi ID or Iqama number? A: Exactly 10 digits — one identity-type digit, eight serial digits, and a final check digit. Q: Can this validator tell if an Iqama is expired? A: No. It only checks the number's mathematical structure. Expiry, status and registration can only be confirmed through Absher or the Ministry of Interior. #### Colombia Cédula & NIT Validator URL: https://geratools.com/colombia-cedula-validator Free Colombian cédula and NIT validator. Format-check a cédula de ciudadanía and compute or verify the NIT verification digit (DV) with the official DIAN modulo-11 algorithm. Privacy-first and runs entirely in your browser — nothing is sent anywhere. How to use: 1. Choose the document type: Select cédula de ciudadanía to format-check, or NIT to compute and verify the check digit. 2. Enter the number: Type the cédula (6–10 digits) or the NIT base, optionally followed by a dash and the verification digit. 3. Read the result: For a NIT the tool shows the computed verification digit and whether a provided digit matches. FAQ: Q: Why can't a cédula de ciudadanía be fully validated? A: The Colombian cédula is a plain serial number with no public check digit, so only its format (6–10 numeric digits) can be verified. There is no algorithm to confirm a specific cédula is real. Q: How accurate is the NIT check digit? A: The NIT verification digit uses the official DIAN modulo-11 algorithm with weights 3,7,13,17,19,23,29,37,41,43,…, so the computed digit is exact. It confirms the number is well-formed, not that it is registered. Q: What is the difference between a cédula and a NIT in Colombia? A: The cédula de ciudadanía is the personal national ID, a plain serial number with no check digit. The NIT is the tax identification number for businesses and individuals, and it carries a modulo-11 verification digit (DV). Q: How is the NIT verification digit calculated? A: Reading the base number right to left, each digit is multiplied by the DIAN weights 3, 7, 13, 17, 19, 23, 29, 37, 41, 43, 47, 53, 59, 67, 71. The products are summed and taken modulo 11; if the remainder is 0 or 1 the DV is that remainder, otherwise the DV is 11 minus the remainder. Q: Is my document number sent anywhere? A: No. Every check runs locally in your browser and the number is never sent anywhere or compared against any registry. Q: Is a person's NIT the same as their cédula? A: For natural persons registered with the DIAN, yes — the NIT base is the cédula number, with the modulo-11 verification digit appended. The same digits can therefore appear as a bare cédula in one system and as a NIT with DV in another, so always record the document type. Q: Should the dots and dash in a NIT be included when validating? A: No. The format 900.373.115-3 is presentation only. Strip dots, dashes, and spaces, validate the base digits, and compare the computed DV against the digit after the dash. Never concatenate the DV onto the base before recomputing. #### Australia TFN Validator — Tax File Number Checksum URL: https://geratools.com/australia-tfn-validator Free Australian TFN validator. Verify a Tax File Number using the ATO's weighted modulus-11 checksum for 8- and 9-digit TFNs. Privacy-first — runs entirely in your browser, nothing is uploaded or sent anywhere. How to use: 1. Enter the TFN: Type or paste the Tax File Number — 9 digits (older TFNs are 8 digits). Spaces are ignored. 2. Read the result: The validator runs the weighted modulus-11 checksum and tells you whether the TFN is valid. 3. Review the checksum: The breakdown shows the weighted sum and the modulus-11 result so you can see why it passed or failed. FAQ: Q: How is an Australian TFN validated? A: A TFN is normally 9 digits (older numbers are 8). Each digit is multiplied by a position weight — 1,4,3,7,5,8,6,9,10 for 9-digit TFNs and 10,7,8,4,6,3,5,1 for 8-digit TFNs — the products are summed, and the total must be divisible by 11. Q: Does a valid checksum mean the TFN is registered to someone? A: No. The modulus-11 checksum only confirms the number is mathematically well-formed. It cannot tell you whether the TFN was actually issued or who holds it, and this tool never contacts the ATO or any other system. Q: How many digits is an Australian TFN? A: Modern TFNs are 9 digits. Some older TFNs are 8 digits. This validator handles both lengths and applies the correct weight set automatically. Q: Is my TFN sent anywhere? A: No. The validator is privacy-first. The checksum runs locally in your browser with JavaScript — there are no network requests and your TFN never leaves your device. Q: Is a TFN the same as an ABN? A: No. A TFN is a private 8- or 9-digit tax identifier for a person or entity, while an ABN is a public 11-digit business identifier with a completely different checksum (a modulus-89 scheme). An 11-digit number from a contractor is an ABN and will not validate here. Q: Can any business collect and store TFNs? A: No. Under Australia's Privacy (Tax File Number) Rule, only entities with a tax, superannuation, or specific statutory purpose — such as employers, super funds, and banks — may collect TFNs, and they must not be used as a general identifier. Systems handling TFNs should encrypt them and never log full numbers. ### Exams & Admissions #### JAMB / Post-UTME / WAEC Aggregate Score Calculator URL: https://geratools.com/jamb-aggregate-calculator Free Nigerian university aggregate score calculator. Combine your JAMB score, Post-UTME and WAEC O'level grades into an admission aggregate using the common 50/30/20 model, with adjustable weights for your school. Runs entirely in your browser. How to use: 1. Enter your JAMB score: Type your JAMB UTME score out of 400. 2. Enter Post-UTME and O'level: Add your Post-UTME score out of 100 and pick your best five WAEC or NECO grades. 3. Read your aggregate: See your aggregate out of 100, with each component broken out. Adjust the weights to match your university. FAQ: Q: How is a Nigerian university aggregate calculated? A: A common model scales JAMB to 50%, Post-UTME to 30% and O'level grade points to 20%, giving an aggregate out of 100. Each university sets its own weighting and cut-off mark, so this tool lets you change the weights. Q: How do you convert a JAMB score to the 50% weighting? A: Divide your JAMB score by 400 and multiply by the JAMB weight. With the default 50% weight, a JAMB of 250 contributes (250 ÷ 400) × 50 = 31.25 points to your aggregate. Q: How are WAEC O'level grades scored? A: This calculator uses the standard 6-point screening scale — A1 is 6 points down to C6 at 1 point, with D7 to F9 scoring 0 — and uses your best five subjects. The five subjects can score a maximum of 30 points, which is then scaled to the O'level weight. Q: What aggregate score do I need for admission? A: There is no fixed national number — each university and each course sets its own cut-off, often anywhere from the high 40s to the 70s out of 100 for competitive courses. Use this tool to compute your own aggregate, then compare it against your target school's published cut-off. Q: Can I use this for NECO instead of WAEC? A: Yes. NECO uses the same A1–F9 grading scale as WAEC, so the 6-point conversion is identical. Pick your best five NECO grades exactly as you would for WAEC. Q: Is this the official formula? A: No single national formula exists. The default 50/30/20 model is widely used, but always check your chosen university's own aggregate formula and cut-off, then adjust the weights in the tool to match. #### CEFR Language Level Checker URL: https://geratools.com/cefr-level-checker Enter your score on a major language exam — DELF/DALF, Goethe-Zertifikat, DELE, HSK, JLPT or TCF — to see the matching CEFR level (A1 to C2) using the official Council of Europe alignment for each test. How to use: 1. Choose your exam: Select the language exam you sat — its scoring system and CEFR mapping are built in. 2. Enter your score: Type the numeric score or, for tiered exams, pick the level you achieved. 3. Read your CEFR level: The tool returns the corresponding CEFR band from A1 (beginner) to C2 (mastery) with a short description. FAQ: Q: What is the CEFR? A: The Common European Framework of Reference for Languages is a six-level scale — A1, A2, B1, B2, C1, C2 — defined by the Council of Europe to describe language ability. A1/A2 are basic users, B1/B2 independent users, and C1/C2 proficient users. Q: How do exam scores map to CEFR? A: Each exam body publishes its own CEFR alignment. Some exams (Goethe, DELF, JLPT) are designed at a specific CEFR level, so passing equals that level. Others (TCF, HSK) report a score that falls into a band. This tool uses the published thresholds for each test. Q: Is the HSK to CEFR mapping exact? A: It is approximate. The pre-2021 HSK levels were loosely aligned (HSK 4 to about B2, HSK 6 to about C1), but Hanban and independent studies disagree on the upper bands. The new HSK 3.0 standard reorganises these levels, so treat the result as a guide. Q: Does JLPT map cleanly onto CEFR? A: Only roughly. The JLPT is not built on the CEFR, and Japanese differs structurally from European languages, so equivalences (N1 near C1-C2, N2 near B2) are widely cited estimates rather than an official one-to-one alignment. Q: Can one score equal different CEFR levels? A: Within a single exam, a higher score means a higher or equal CEFR band — it never drops. Across different exams the same nominal number is not comparable, which is exactly why each test needs its own mapping table rather than a shared scale. #### Credit Hour to Workload Hours Calculator URL: https://geratools.com/credit-hour-to-workload-calculator Enter your total enrolled credit hours (and course types) to estimate expected weekly workload hours using the Carnegie Unit standard (2-3 hours out-of-class per credit hour). How to use: 1. Enter your credit hours: Type your total enrolled credit hours for the term, the number you see on your registration. 2. Pick the study ratio: Choose a low, standard, or high out-of-class ratio depending on how demanding your courses are. 3. Read your weekly hours: The tool adds in-class contact time to the estimated out-of-class study time to give a total weekly commitment. FAQ: Q: What is the Carnegie Unit standard? A: The Carnegie Unit defines one credit hour as one hour of classroom instruction plus two to three hours of out-of-class student work per week, for roughly 15 weeks. It is the basis most US universities use to define a credit. Q: How many hours should a full course load take? A: A typical 15-credit full-time load means about 15 hours in class plus 30 to 45 hours of study, for a total of 45 to 60 hours a week. That is why full-time study is treated as a full-time job. Q: Why is the out-of-class ratio a range? A: The standard allows 2 to 3 hours of study per credit hour because course difficulty varies. Introductory or lab-heavy courses may sit near 2, while writing-intensive or upper-level seminars often demand 3 or more. Q: Does this include exam weeks? A: No. The estimate is a typical week during the term. Exam and project weeks usually spike well above the average, so plan buffer time around deadlines rather than relying on the steady-state figure. Q: Should online or accelerated courses use the same ratio? A: Accelerated courses compress the same total workload into fewer weeks, so weekly hours rise sharply. A standard semester course in a 6-week summer term roughly doubles the weekly study time shown here. #### UK Honours Borderline Case Tool URL: https://geratools.com/honours-classification-borderline-tool Enter your UK weighted average mark to see whether you fall within the standard borderline zone (within 2% below a classification boundary) and which discretionary factors like an improving trajectory or credit profile could count in your favour. How to use: 1. Enter your weighted average: Type your overall weighted average mark out of 100 as calculated by your university's classification rules. 2. Optionally add a credit profile: Enter the percentage of credits you scored in the higher class to see whether a profile-based upgrade route may apply. 3. Read the verdict: The tool names your provisional classification, tells you whether you are inside the standard 2% borderline zone, and lists the discretionary factors boards commonly consider. FAQ: Q: What counts as a borderline at most UK universities? A: A common rule is being within 2 percentage points below a classification boundary — for example 68.0–69.9 for a First, or 58.0–59.9 for a 2:1. Some institutions use a 3% zone or a credit-profile rule instead. Always check your own university's regulations, because there is no single national standard. Q: Does being in the borderline guarantee an upgrade? A: No. The borderline only makes you eligible for a discretionary review. Exam boards weigh factors like the share of credits already in the higher band, performance in the final year, and the trend of your results. Many borderline candidates are not upgraded. Q: What is the credit-profile rule? A: Some universities upgrade a borderline student automatically if a set proportion of their credits — often 50% or more, sometimes weighted to later years — were achieved in the higher classification band. This tool flags when that route may apply so you can check your exact regulation. Q: Which boundaries does this use? A: It uses the standard UK honours boundaries: First Class at 70, Upper Second (2:1) at 60, Lower Second (2:2) at 50, and Third at 40. Marks below 40 are typically a fail or ordinary degree depending on your programme. Q: Is anything I type stored? A: No. The calculation happens entirely in your browser. Nothing is uploaded or saved to a server. #### International Grade Conversion Tool URL: https://geratools.com/international-grade-conversion-tool Select your country and enter your grade on the local scale to get the WES or NACES equivalent US GPA and ECTS grade, covering 30 common source countries for international students applying abroad. How to use: 1. Pick your country: Choose the country whose grading system issued your transcript from the dropdown. 2. Enter your local grade: Type your grade on that country's own scale, such as a percentage, a 10-point mark, or a letter. 3. Read the equivalents: The tool maps your grade to a US 4.0 GPA band and the nearest ECTS letter so you can compare against US or European admission requirements. FAQ: Q: Is this conversion officially accepted by universities? A: It is a guide based on widely published WES and NACES band tables, not an official evaluation. Most universities require a formal credential evaluation from an approved agency, which this tool can help you anticipate but does not replace. Q: Why do different agencies give different GPAs for the same grade? A: WES, ECE, and SpanTran each use slightly different conversion methodologies and rounding. This tool follows the common WES-style banding, so a result one tenth off from another agency is normal and expected. Q: How does ECTS differ from a US GPA? A: ECTS uses letter grades A to F based on the rank distribution of students, while a US GPA is a numeric average on a 4.0 scale. The two measure achievement differently, so the tool shows an approximate cross-walk rather than an exact match. Q: What if my country is not listed? A: Pick the system closest to yours, such as a generic percentage scale, as a rough guide. For an accurate result with an unlisted system, request a formal evaluation from WES or another NACES member. Q: Does a higher local grade always mean a higher GPA? A: Within one country's scale, yes. Across countries it varies, because a passing mark in one system maps to a different GPA band than the same number elsewhere. Always convert using your own country's scale. #### JLPT Japanese Proficiency Level Checker URL: https://geratools.com/jlpt-level-checker Answer a brief self-assessment on kanji, vocabulary, and grammar knowledge to estimate your JLPT level (N5 through N1) and CEFR alignment for Japanese visa and job applications. Runs in your browser. How to use: 1. Answer the self-assessment: Move each slider to reflect how many kanji and vocabulary words you know and how much grammar you have studied. 2. Review your estimate: The tool weighs your kanji, vocabulary, and grammar inputs against the published targets for each JLPT level. 3. Read your level and CEFR alignment: See the highest JLPT level your knowledge supports, from N5 up to N1, with an approximate CEFR band for applications. FAQ: Q: What are the JLPT levels? A: The Japanese-Language Proficiency Test has five levels. N5 is the most basic and N1 is the most advanced. N4 and N3 sit in the lower-intermediate range, while N2 and N1 are the levels most often required for university study and professional work in Japan. Q: How much kanji and vocabulary does each level need? A: A common guide gives roughly 100 kanji and 800 words for N5, 300 kanji and 1,500 words for N4, 650 kanji and 3,750 words for N3, 1,000 kanji and 6,000 words for N2, and around 2,000 kanji and 10,000 words for N1. Grammar load rises in step with these figures. Q: How does JLPT map to CEFR? A: There is no official mapping, but a frequently cited guide aligns N5 with A1, N4 with A2, N3 with B1, N2 with B2, and N1 with C1. Because the tests measure different skills, treat the CEFR band as approximate when quoting it on applications. Q: Why does the estimate weigh three inputs? A: Passing the JLPT requires balanced ability. Knowing thousands of words but little grammar, or lots of grammar but few kanji, will not carry you through a higher level. The tool takes the limiting factor among kanji, vocabulary, and grammar so a single strong area does not overstate your level. Q: Is this a substitute for a practice exam? A: No. The JLPT tests reading and listening under time pressure, and self-reported knowledge tends to be optimistic. Use this to target a level, then confirm with an official past paper before registering for that level's exam. #### Semester Weeks Calculator URL: https://geratools.com/semester-weeks-calculator Free semester weeks calculator — enter the first and last day of a term to see how many weeks and days it runs, inclusive of both dates. Runs entirely in your browser. How to use: 1. Enter the start date: Pick the first day of the semester or term. 2. Enter the end date: Pick the last day of the semester or term. 3. Read the length: The result shows full weeks plus any extra days, counting both endpoints. FAQ: Q: Does the count include both the start and end dates? A: Yes. The total is inclusive of both the first and last day, so a Monday-to-the-following-Sunday term counts as 7 days, or one week. Q: Why does it show extra days as well as weeks? A: Semesters rarely divide into whole weeks, so the result shows the full weeks plus any leftover days, and a decimal weeks figure for convenience. Q: Is any data sent anywhere? A: No. The calculation happens entirely in your browser and nothing is uploaded. Q: How many weeks is a typical semester? A: Most university semesters run around 14 to 16 weeks including exams, while shorter terms or quarters are often 10 to 12 weeks. Enter your actual start and end dates for the exact figure. Q: Does it count holidays and reading weeks? A: No. It counts every calendar day between the dates you enter, including any breaks. If you want only teaching weeks, set the dates to span just the teaching period or subtract the break manually. Q: Why is the count inclusive of both dates? A: A term that runs from Monday to the following Sunday is naturally one full week of 7 days. Counting both endpoints reflects how people describe term length, so a same-day start and end counts as one day. ### More Calculators #### Discount & Sale Price Calculator URL: https://geratools.com/discount-calculator Free discount calculator. Enter an original price and discount percentage to get the final sale price and amount saved. Or reverse it — enter the sale and original price to find the % off. Also calculates stacked (multiple) discounts and their true combined saving. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a mode: Select one of three modes: forward (price + % → sale price), reverse (sale price + original → % off), or stacked (multiple discounts applied in sequence). 2. Enter your numbers: Type the original price and discount percentage. For stacked discounts you can apply up to three discounts in sequence. 3. Read the result: The final price, amount saved and effective percentage off are shown instantly. For stacked discounts the tool also explains why the true saving differs from simply adding the percentages together. FAQ: Q: How does the discount calculator work? A: For a straightforward discount: sale price = original price × (1 − discount% ÷ 100). Amount saved = original price − sale price. For the reverse mode: % off = (original − sale) ÷ original × 100. Q: Why is a stacked discount not the same as adding the percentages? A: Each successive discount applies to the already-reduced price, not the original. For example, 20% off then 10% off gives an effective saving of 28%, not 30%. The formula is: final price = original × (1 − d1/100) × (1 − d2/100) × ... Q: How do I calculate 30% off a price? A: Multiply the price by 0.70 (which is 1 − 30/100). A £50 item at 30% off costs £50 × 0.70 = £35, saving £15. Enter 50 as the original price and 30 as the discount in forward mode. Q: How do I work out the percentage off if I only know the two prices? A: Subtract the sale price from the original, divide by the original, then multiply by 100. An item that dropped from £80 to £60 is (80 − 60) ÷ 80 × 100 = 25% off. Use the reverse mode and enter both prices. Q: Does the order of stacked discounts change the final price? A: No. Because the discounts are multiplied together, 20% then 10% gives the same final price as 10% then 20% — both reach 72% of the original. Order only matters for which intermediate price you see along the way. Q: What's the difference between a discount and a coupon stacked on a sale? A: They are usually multiplicative, not additive. A 25%-off sale plus a 10%-off coupon does not equal 35% off — it equals 1 − (0.75 × 0.90) = 32.5% off. Use stacked mode to get the true combined figure. Q: Is my data private? A: Completely. All calculations run locally in your browser using JavaScript. No prices or percentages are sent to any server. #### Random Letter Generator URL: https://geratools.com/random-letter-generator A free random letter generator. Get one or many random letters from A to Z, choose uppercase or lowercase, limit to vowels or consonants, and turn off repeats. Runs entirely in your browser — instant, fair and private. How to use: 1. Choose how many letters: Set the number of letters you want — one for a single pick, or several for a sequence. 2. Set your options: Pick uppercase or lowercase, restrict the pool to vowels or consonants if you like, and tick No repeats to make every letter unique. 3. Generate: Press Generate to get your random letters, then Copy to put them on your clipboard. FAQ: Q: How does the random letter generator pick letters? A: Each letter is chosen from the selected pool (A–Z, vowels only, or consonants only) using your browser's built-in random number function. Every allowed letter has an equal chance on each pick. Q: Can I get only vowels or only consonants? A: Yes. Switch the letter set to Vowels to draw only from A, E, I, O, U, or Consonants to exclude them. This is handy for word games, teaching phonics, and puzzle making. Q: How do I avoid the same letter appearing twice? A: Turn on No repeats. The generator then draws without replacement, so each letter in the result is unique. With repeats off you can request at most as many letters as the chosen set contains. Q: What is a random letter generator used for? A: Classroom games and spelling practice, choosing a category in games like Scattergories, naming variables or test cases, picking a random starting letter for a challenge, drawing lots, and breaking ties. Q: Is the result private? A: Yes. Everything happens in your browser. Nothing about your settings or results is uploaded, stored or shared. #### ABV Calculator URL: https://geratools.com/abv-calculator Calculate ABV from original gravity (OG) and final gravity (FG) hydrometer readings using both the simple and the more accurate advanced formula. Shows apparent attenuation too. Built for homebrewers tracking fermentation. Runs 100% in your browser. How to use: 1. Enter your original gravity: Read OG with a hydrometer or refractometer before pitching yeast. A typical pale ale starts near 1.050. 2. Enter your final gravity: Take an FG reading once fermentation has stopped (stable gravity over 2–3 days). A typical FG lands near 1.010. 3. Read the ABV: The calculator shows the standard ABV plus the advanced-formula figure and apparent attenuation. Use the advanced figure for stronger brews. FAQ: Q: What is the formula for ABV? A: The simple formula is ABV = (OG − FG) × 131.25. For example, an OG of 1.050 and FG of 1.010 gives (1.050 − 1.010) × 131.25 = 5.25% ABV. The advanced formula corrects for high gravities. Q: Which formula should I use? A: The simple formula is accurate up to about 6–7% ABV. Above that, gravity drop no longer scales linearly with alcohol, so the advanced (alternate) formula gives a more accurate result. Both are shown side by side. Q: What is apparent attenuation? A: Apparent attenuation is the percentage of the original sugar the yeast has converted, measured by hydrometer. It equals (OG − FG) ÷ (OG − 1) × 100. Most ale yeasts attenuate 70–80%. Q: Do I need to correct for temperature? A: Hydrometers are calibrated to a reference temperature (often 20°C / 68°F). Readings taken warmer or colder need a small correction before you enter them here, or the ABV will be slightly off. Q: Is the data sent anywhere? A: No. Every calculation runs locally in your browser. Your gravity readings never leave your device. #### Anchor Scope & Chain Calculator URL: https://geratools.com/anchor-scope-chain-calculator Compute the recommended scope ratio and rode length to deploy from charted depth, tidal rise, bow roller height, rode type, and conditions, plus an estimated swing radius. Recreational and commercial mariners use this when selecting anchorages. How to use: 1. Enter depth and tide: Type the charted depth at low water, the tidal rise expected during your stay, and the bow roller height above the waterline. 2. Choose rode and conditions: Select whether your rode is all chain, mixed, or mostly rope, and pick the expected weather, from a calm lunch stop to a storm. 3. Read the rode to deploy: The tool gives the recommended scope, the total rode to pay out, and an approximate swing radius for judging clearance. FAQ: Q: What is anchor scope? A: Scope is the ratio of rode deployed to the vertical distance from your bow roller down to the seabed. A 5 to 1 scope in 6 metres of working depth means 30 metres of chain. More scope gives a flatter pull on the anchor, which helps it dig in and hold. Q: How much scope should I use? A: A common rule is 5 to 1 for all chain in settled conditions and 7 to 1 or more when it blows. Rope rode needs more, often 7 to 1 up to 10 to 1, because it lacks the heavy catenary that lets chain hold at lower scope. This tool recommends a ratio from your rode type and conditions. Q: Why add the tidal range to the depth? A: Your rode must still reach the seabed at high water, when the water is deepest. If you size it only for the depth at low water it can snub short as the tide rises and pluck the anchor out. Always calculate the working depth at the highest water expected during your stay. Q: Why does the bow roller height matter? A: Scope is measured from the bow roller, not the waterline, so the height of the roller above the water is part of the vertical distance the rode must span. On a high-freeboard vessel this can add a metre or two and noticeably increases the rode needed. Q: What is the swing radius for? A: Once anchored the boat can swing in a circle as the wind and tide change. The swing radius is roughly the horizontal distance from the anchor to the bow, plus the boat length. Use it to keep clear of other boats, moorings, and shallows when choosing your spot. #### Australia Annual Leave Entitlement Calculator URL: https://geratools.com/australia-annual-leave-calculator Calculate Australian annual leave under the National Employment Standards. Applies the 4-week minimum (5 weeks for qualifying shift workers), computes progressive accrual from ordinary hours, and values the payout at end of employment. Runs in your browser. How to use: 1. Set the worker type: Tick the shift-worker box if the employee qualifies for 5 weeks, otherwise the standard 4-week minimum applies. 2. Enter hours and weeks worked: Type the ordinary hours worked each week and the number of weeks worked, which drives the progressive accrual. 3. Read accrued leave and payout: The tool shows accrued hours and days, the full-year entitlement, and an optional payout value at your base hourly rate. FAQ: Q: What is the Australian minimum annual leave? A: The National Employment Standards give full-time and part-time employees 4 weeks of paid annual leave per year, based on their ordinary hours of work. Certain shift workers qualify for 5 weeks. Leave accrues progressively rather than being granted all at once. Q: How does accrual work? A: Leave accrues for every ordinary hour worked at a rate of the weeks of entitlement divided by 52. For a standard worker that is 4 over 52, so about 0.0769 hours of leave per ordinary hour. The tool multiplies this by the hours you worked to give accrued leave. Q: How is part-time leave calculated? A: Part-time employees accrue the same 4 weeks, but a week is measured by their ordinary hours. Someone working 20 ordinary hours a week accrues 4 times 20, so 80 hours of leave a year. Enter their actual ordinary hours per week. Q: Do casual employees get annual leave? A: No. Casual employees are not entitled to paid annual leave and instead receive a casual loading, commonly 25%, to compensate. When a casual converts to permanent employment, paid leave begins accruing from the conversion date forward. Q: Does the payout include leave loading? A: The payout figure shown is the base value, accrued hours times your hourly rate. Many awards and agreements add annual leave loading, often 17.5%, on termination payouts. Add that on top of the base figure where it applies to the employee. Q: Does annual leave accrue while I am on leave? A: Yes, during paid leave. Annual leave continues to accrue while an employee is on paid annual leave or paid personal/carer's leave. It generally does not accrue during unpaid leave periods such as unpaid parental leave, which is a common reason a balance is lower than expected. Q: Does overtime count toward leave accrual? A: No. Accrual is based on ordinary hours of work only. An employee whose ordinary week is 38 hours accrues on 38 hours even in weeks where they work paid overtime on top. #### Bead Count & Spacing Calculator URL: https://geratools.com/bead-count-calculator Enter bead diameter and desired finished length to compute bead count, total thread length with waste, and optional pattern repeat counts. For jewelry makers and beaders planning bracelets and necklaces. How to use: 1. Enter bead size and length: Type your bead diameter in millimetres and the finished length you want in centimetres or inches. 2. Add spacing if used: If you string spacer beads or knots, enter the gap between beads so the count reflects real spacing. 3. Read counts and thread length: The tool shows total beads, beads per inch, pattern repeats, and the stringing material length including a waste allowance for clasps and knots. FAQ: Q: How is the number of beads calculated? A: The finished length is divided by the per-bead pitch, which is the bead diameter plus any spacing gap you add. A 20 cm bracelet with 6 mm beads and no gap fits about 33 beads (200 mm divided by 6 mm). Q: Why does the thread length add extra? A: You always need slack beyond the beaded section for tying knots, attaching a clasp, and finishing. The tool adds a waste allowance (default 15 cm) on top of the beaded length so you cut enough cord or wire the first time. Q: What is beads per inch used for? A: Beads per inch is a quick density figure for comparing bead sizes and estimating how many beads a pattern row needs. It equals 25.4 mm divided by your bead pitch in millimetres. Q: How do pattern repeats work? A: If your design uses a repeating motif of N beads, the tool divides the total bead count by N to show how many full repeats fit and how many leftover beads remain, so you can centre or adjust the pattern. Q: Should I measure the bead hole-to-hole or outer diameter? A: Use the outer diameter (the nominal bead size, like 4 mm or 8 mm). On a tight strand beads sit edge to edge, so the outer diameter is the effective pitch. Add a spacing gap only if beads are deliberately separated. #### Beaufort Scale Wind & Sea State Reference URL: https://geratools.com/beaufort-scale-reference A full Beaufort scale lookup with conversion between force number, knots, m/s, km/h, probable wave height, and standard sea-state descriptions. Mariners, offshore workers, and weather observers use this as a quick field reference. How to use: 1. Enter a wind speed: Type the measured wind speed and pick its unit, knots, metres per second, or kilometres per hour. 2. Read the matching force: The tool returns the Beaufort force number, its name, the speed in all three units, and the sea-state description. 3. Scan the full table: Use the table below to compare any force against its speed ranges and probable open-sea wave height, with the matched row highlighted. FAQ: Q: What is the Beaufort scale? A: The Beaufort scale is a 0 to 12 measure of wind force based on observed effects on the sea and on land. It was devised by Francis Beaufort in 1805 and is now defined by the World Meteorological Organization with a specific wind-speed range for each force. Q: How is force calculated from wind speed? A: The empirical relation is v equals 0.836 times B to the power 1.5, where v is wind speed in metres per second and B is the Beaufort number. Inverting it gives B equals the speed over 0.836 raised to the two-thirds power, which this tool rounds to the nearest force. Q: What wave heights does the table show? A: The probable wave heights are the WMO open-sea figures for a fully developed sea well away from land. In sheltered water or where the fetch is short, the waves for a given force will be noticeably lower. Q: At what height is wind speed measured? A: Beaufort wind speeds are referenced to the standard meteorological height of 10 metres above the surface. Wind measured lower down, such as at deck level, will read lighter than the equivalent Beaufort speed. Q: When does a gale warning apply? A: A gale begins at Beaufort force 8, which is 34 knots and above. Force 9 is a strong gale, force 10 a storm, force 11 a violent storm, and force 12 a hurricane at 64 knots and above. Forecasters issue gale warnings from force 8 upward. #### Big Integer Calculator URL: https://geratools.com/big-integer-calculator Add, subtract, multiply, divide, and take the modulo of arbitrarily large integers with exact results, using BigInt. No precision loss like floating-point — compute with hundred-digit numbers safely. Includes quotient, remainder, and power. Runs in your browser. How to use: 1. Enter two integers: Type each operand as a whole number. There is no size limit — paste numbers with hundreds of digits if you like. 2. Pick an operation: Choose add, subtract, multiply, divide, modulo, or power. Division reports both the integer quotient and the remainder. 3. Read the exact result: The answer is computed with BigInt, so it is exact to the last digit with no rounding. FAQ: Q: Why can't a normal calculator handle big integers? A: JavaScript and most calculators use 64-bit floating-point, which is only exact up to about 9 quadrillion (2^53). Beyond that, digits are silently rounded. BigInt stores integers of any size exactly, so results stay precise. Q: How does integer division work here? A: Division gives the integer quotient (truncated toward zero) and the remainder, since BigInt does not produce fractions. For example 17 divided by 5 is quotient 3, remainder 2. Dividing by zero is rejected. Q: What about the power operation? A: Power raises the first integer to the second. Because results grow extremely fast, the exponent is capped at a reasonable size to keep the page responsive — but within that range the result is exact. Q: Are negative numbers supported? A: Yes for add, subtract, and multiply. Modulo follows BigInt's sign rule where the remainder takes the sign of the dividend, and the power exponent must be non-negative since negative powers are not integers. #### Canada EI Premium Calculator URL: https://geratools.com/canada-ei-premium-calculator Applies the annual EI premium rate (1.64 percent) and maximum insurable earnings cap to compute the employee deduction and the 1.4 times employer contribution. Useful for Canadian payroll, employees, and small-business owners. How to use: 1. Enter your insurable earnings: Type the gross insurable earnings for the year (or pay period). EI applies to most employment income. 2. Read the employee premium: The tool multiplies insurable earnings (capped at the annual maximum) by the EI rate to show the amount deducted from pay. 3. Review the employer share: Employers pay 1.4 times the employee premium, so the combined cost is also shown. FAQ: Q: What is the current EI premium rate? A: The 2024 employee EI premium rate is 1.66 percent of insurable earnings outside Quebec (1.32 percent in Quebec). This tool lets you set the rate and defaults to the federal figure. Employers pay 1.4 times the employee amount. Q: What are maximum insurable earnings? A: Maximum insurable earnings (MIE) is the annual cap above which no further EI premium is charged. For 2024 it is 63,200 CAD, giving a maximum employee premium of about 1,049 CAD. Earnings above the cap are not subject to EI. Q: Why does the employer pay more than the employee? A: By law, Canadian employers contribute 1.4 times the employee's EI premium. So for every dollar an employee pays, the employer pays 1.40 dollars, reflecting the shared funding of the EI program. Q: Is Quebec different? A: Yes. Quebec residents pay a lower EI rate because Quebec runs its own parental insurance plan (QPIP). Set the rate to the Quebec figure (1.32 percent for 2024) if you work in Quebec. Q: Does EI come off before or after income tax? A: EI is a statutory deduction taken from gross pay alongside CPP. It is calculated on insurable earnings, not on income after tax, and it reduces your take-home pay separately from income tax withholding. Q: What happens if I work two jobs and overpay EI? A: Each employer deducts EI independently, so with two jobs you can exceed the annual maximum. The excess employee premium is refunded through your income tax return. Employers cannot recover their matching over-contribution. Q: Why did EI deductions restart in January after I maxed out? A: The maximum insurable earnings cap applies per calendar year. Deductions stop once your year-to-date insurable earnings hit the cap, but the counter resets on 1 January and premiums resume on the first pay of the new year at the newly announced rate and MIE. #### Capital Gains Tax Calculator (2026) URL: https://geratools.com/capital-gains-tax-calculator-2026 Calculate your 2026 federal capital gains tax. Applies the 0%/15%/20% long-term rates using the 2026 income thresholds, treats short-term gains as ordinary income, and adds the 3.8% Net Investment Income Tax above $200,000 single / $250,000 joint. How to use: 1. Enter your gain and holding period: Type the size of your capital gain and choose long-term (held over a year) or short-term (held a year or less). 2. Add your other taxable income: Enter your ordinary taxable income so the calculator can stack the gain on top and pick the correct long-term rate band. 3. Read the tax and effective rate: See the breakdown by 0%/15%/20% bands (or ordinary tax for short-term), any 3.8% NIIT, and your effective rate on the gain. FAQ: Q: How are 2026 long-term capital gains taxed? A: Long-term gains use 0%, 15%, and 20% bands stacked on top of your ordinary income. In 2026 the 0% band runs up to $48,350 single / $96,700 joint of total income, 15% up to $533,400 single / $600,050 joint, and 20% above that. Q: How is a short-term gain taxed differently? A: A short-term gain (held a year or less) is taxed as ordinary income at your marginal bracket, not the 0/15/20 rates. The tool computes it as the extra ordinary tax from stacking the gain on top of your other income, which can reach 37%. Q: What is the 3.8% Net Investment Income Tax? A: NIIT adds 3.8% on the smaller of your net investment income (the gain) or the amount your modified AGI exceeds $200,000 single / $250,000 joint. A single filer with $300,000 income and a $50,000 gain pays 3.8% on the full $50,000, or $1,900, on top of capital gains tax. Q: Can my long-term gain really be taxed at 0%? A: Yes. If your ordinary income plus the gain stays within the 0% band ($48,350 single / $96,700 joint in 2026), the long-term portion inside that band is taxed at 0%. A single filer with $30,000 of ordinary income and an $15,000 long-term gain pays $0 federal tax on that gain. #### Cloud Base Calculator URL: https://geratools.com/cloud-base-calculator Estimate convective cumulus cloud base height using the lifted condensation level rule, dividing the temperature and dew point spread by 2.5 degrees Celsius per 1,000 ft. Enter surface temperature, dew point, and field elevation for a base in feet AGL and MSL. How to use: 1. Pick your temperature unit: Choose Celsius or Fahrenheit, then enter values in that unit for both temperature and dew point. 2. Enter temperature and dew point: Type the surface temperature and surface dew point from a METAR or local observation. 3. Read the cloud base: The tool divides the spread by 2.5 degrees per 1,000 ft and shows the estimated base in feet above ground and above sea level. FAQ: Q: How is cloud base estimated? A: It uses the lifted condensation level rule of thumb: divide the temperature minus dew point spread in degrees Celsius by 2.5, then multiply by 1,000 ft. A 10-degree spread gives a base near 4,000 ft above the ground. Adding field elevation gives the height above sea level. Q: Why 2.5 degrees per 1,000 ft? A: As a parcel of air rises it cools at about 3 degrees Celsius per 1,000 ft, while its dew point falls more slowly at about 0.5 degrees per 1,000 ft. The spread therefore closes at roughly 2.5 degrees per 1,000 ft, and cloud forms where the two meet. Q: Which clouds does this predict? A: Only convective cumulus cloud, the puffy fair-weather and shower clouds formed by surface heating and lifting. Stratus, frontal, and orographic cloud form by different processes such as advection or large-scale ascent and will not match this estimate. Q: Is AGL or MSL more useful? A: Pilots usually plan ceilings in feet above ground level, which is what this rule produces directly. The above-sea-level figure helps when comparing to charted obstacle and terrain elevations. Enter the field elevation to get both. Q: How accurate is it? A: It is a quick estimate, typically within a few hundred to a thousand feet for well-mixed afternoon convection. Strong inversions, advection, and moisture layers aloft can shift the real base. Always cross-check with an actual METAR ceiling and a current forecast. #### Combustion Air Opening Size Calculator (IMC 701) URL: https://geratools.com/combustion-air-opening-calculator Enter total appliance input and room volume to test whether a space is confined, then size the required combustion air openings using the IMC 701 standard methods: 1 in² per 1000, 2000, 3000, or 4000 BTU/h depending on indoor or outdoor source. For plumbers and HVAC techs. Runs in your browser. How to use: 1. Enter total appliance input and room volume: Add up the BTU/h input of every fuel-burning appliance in the room and enter the room volume in cubic feet. 2. Choose the combustion air source method: Pick whether air comes from indoors or outdoors and through which configuration, since each uses a different square-inch-per-BTU rule. 3. Read the required opening size: The tool tells you whether the space is confined and gives the free area each opening needs, plus a round-duct equivalent diameter. FAQ: Q: How do I know if a space is confined? A: A space is confined if its volume is less than 50 cubic feet per 1000 BTU/h of total appliance input. The tool runs this test for you; a confined space needs dedicated combustion air openings while an unconfined space of tight construction may still need them. Q: Why do indoor and outdoor openings use different sizes? A: Outdoor air is denser and more reliable, so the code allows smaller openings, such as 1 square inch per 4000 BTU/h for vertical ducts. Air drawn from an adjacent indoor room is less assured, so it requires a much larger 1 square inch per 1000 BTU/h opening. Q: What is free area versus gross area? A: Free area is the net open area after the blockage of a louver or grille. A metal louver typically passes only about 25 percent of its gross area and a wood louver about 75 percent, so you must enlarge the gross opening to deliver the required free area. Q: Do I always need two openings? A: Most methods require two openings, one within 12 inches of the top of the space and one within 12 inches of the bottom, to create convective airflow. A single combined outdoor opening is allowed under specific conditions and uses the 1 square inch per 3000 BTU/h rule. Q: Does this cover direct-vent or sealed-combustion equipment? A: No. Direct-vent, sealed-combustion, and engineered or mechanical combustion air systems draw air through their own piping and follow separate rules. This tool covers the standard atmospheric and natural-draft openings under IMC 701 and IFGC 304. #### Contingency Fee Calculator URL: https://geratools.com/contingency-fee-calculator Calculate the attorney contingency fee, deduct case costs and medical liens, and show the client's net recovery. Supports separate pre-litigation and post-litigation fee percentages and choice of fee-before-costs or costs-before-fee ordering. How to use: 1. Enter the gross recovery: Type the total settlement or verdict amount before any fees, costs, or liens are deducted. 2. Set the fee percentage and ordering: Enter the contingency rate (for example 33.3% pre-litigation or 40% if the case was filed) and choose whether the fee is taken before or after costs. 3. Add costs and liens: Enter case costs (filing fees, experts, records) and any medical liens; the tool deducts them and shows the client's net proceeds. FAQ: Q: How is a contingency fee calculated? A: The fee is a percentage of the gross recovery — commonly one third before a lawsuit is filed and forty percent afterward. Whether the percentage applies to the gross recovery or to the recovery after costs are subtracted depends on the fee agreement, and changes the dollar fee, so this tool lets you pick the ordering. Q: What is the difference between fee-before-costs and costs-before-fee? A: Fee-before-costs (the gross method) takes the percentage of the full recovery, then subtracts costs from the client's share. Costs-before-fee (the net method) subtracts costs first, then takes the percentage of what remains, which produces a smaller fee. Many states default to or require the net method unless the agreement says otherwise. Q: How do medical liens affect the client's net? A: Medical providers, health insurers, or government programs may hold liens that must be paid from the recovery. The tool subtracts liens after the fee and costs to show the client's true take-home amount, which is often far less than the gross settlement. Q: Are contingency percentages capped? A: Some jurisdictions and case types cap contingency fees — for example sliding scales in medical-malpractice or minors' cases, or limits in certain federal claims. This calculator applies the rate you enter; always confirm any statutory cap that applies to your matter. Q: Does the fee include case costs? A: No. The attorney fee is separate from case costs such as court filing fees, expert witnesses, and medical-record charges. Costs are reimbursed to the firm out of the recovery; the fee is the firm's compensation. This tool itemizes both. #### Cooling Load Quick Estimate (Rule of Thumb) Calculator URL: https://geratools.com/cooling-load-rule-of-thumb-calculator Applies published BTU per square foot rule-of-thumb ranges by climate zone and building type, then adjusts for window area, occupants, and lighting to give a quick preliminary tonnage estimate before a formal Manual J. For HVAC contractors quoting on the phone. Runs in your browser. How to use: 1. Enter area and building details: Type the conditioned floor area, then pick the building type and climate zone that best match the project. 2. Add the adjustments: Enter the window-to-floor ratio as a percent, the number of occupants, and the lighting power density in watts per square foot. 3. Read the tonnage: The tool returns an estimated cooling load in BTU per hour and tons, broken down by envelope, people, and lighting gains. FAQ: Q: How accurate is a rule-of-thumb cooling estimate? A: It is a ballpark figure meant for phone quotes and feasibility, not equipment selection. Rule-of-thumb numbers can be off by 20 percent or more, so always run a full ACCA Manual J load calculation before buying or installing equipment. Q: How many BTU per square foot does a home need? A: Residential cooling typically falls between about 20 and 35 BTU per hour per square foot depending on climate, insulation, and window area. Offices and retail run higher because of internal heat from people, lighting, and equipment. Q: Why does the window ratio matter so much? A: Windows admit far more solar heat than insulated walls. A higher window-to-floor ratio adds significant cooling load, which is why the tool increases the estimate above a baseline ratio and decreases it below. Q: How is occupant heat gain figured? A: Each person adds sensible and latent heat. The tool uses roughly 400 BTU per hour per person for homes and 600 for offices and retail, where activity levels and ventilation requirements are higher. Q: What is a ton of cooling? A: One ton of cooling equals 12,000 BTU per hour, historically the rate needed to melt one ton of ice in 24 hours. The tool divides total BTU per hour by 12,000 to express the load in tons. #### Dark Frame Count Optimization Calculator URL: https://geratools.com/dark-frame-optimization-calculator Computes the diminishing-returns curve for dark-frame stacking. A master dark made from N darks adds residual noise scaled by 1/sqrt(N); this tool shows the noise penalty for each count so you stop wasting time past the useful point. For astrophotographers streamlining calibration. How to use: 1. Enter your planned dark count: Type the number of dark frames you intend to capture for the master dark. 2. Read the residual noise penalty: The tool shows how much extra noise the master dark injects into each calibrated light, as a fraction of a single dark's noise, and the marginal gain from one more frame. 3. Find the sweet spot: Compare the penalty at your count against larger counts. Once the marginal improvement is tiny, more darks are wasted effort. FAQ: Q: Why do more dark frames reduce noise? A: A single dark frame is noisy, and subtracting it injects that noise into your light. Averaging N darks into a master dark reduces the master's noise by the square root of N, so the noise it adds during subtraction shrinks the more darks you stack. Q: How many dark frames is enough? A: The improvement follows a 1 over square-root-of-N curve, so returns fall off fast. Going from 1 to 16 darks cuts the added noise by 75 percent, but going from 50 to 100 only trims it by a few percent. Many imagers settle on 20 to 50 darks as a practical sweet spot. Q: What does the residual noise figure mean? A: It is the extra random noise the master dark adds to each calibrated light frame, expressed relative to the noise of one raw dark. A figure of 0.2 means the master injects only 20 percent of a single dark's noise, because averaging has smoothed it out. Q: Does stacking darks affect my final image SNR? A: Yes, indirectly. A noisy master dark raises the noise floor of every calibrated light, which slightly lowers your final stacked SNR. A well-averaged master dark keeps that penalty negligible, which is the whole point of taking enough of them. Q: Do darks need to match my lights? A: Yes. Darks must match the light frames in exposure length, ISO or gain, and sensor temperature. The count optimised here assumes matched darks; mismatched darks can add fixed-pattern artefacts no amount of averaging will fix. #### Dew Point Risk Calculator for Optics URL: https://geratools.com/dew-point-optics-calculator Enter ambient temperature and relative humidity to compute the dew point and the margin to it using the Magnus formula. Optical surfaces radiate heat and cool below ambient, so a small margin means dew. For visual and imaging astronomers at the telescope. How to use: 1. Enter the ambient temperature: Type the current air temperature in degrees Celsius. A phone weather app or a simple thermometer at your observing site is fine. 2. Enter the relative humidity: Add the relative humidity as a percentage. Humid nights have a dew point close to the air temperature. 3. Read the dew margin: The tool shows the dew point and how many degrees the air sits above it. A small margin means optics will dew, so deploy a dew heater early. FAQ: Q: Why do telescope optics dew when the air has not? A: Optical surfaces facing the open sky radiate heat away and cool a few degrees below the surrounding air. If they drop to the dew point before the air does, moisture condenses on the glass even while the air itself stays clear. That is why a dew heater keeps optics a degree or two above ambient. Q: How is the dew point calculated? A: The tool uses the Magnus-Tetens formula. It converts temperature and relative humidity into the actual water vapour content, then finds the temperature at which that vapour would saturate the air. That saturation temperature is the dew point. Q: What dew margin is risky? A: When the air is within about 3 degrees of the dew point, radiating optics will very likely dew over within an hour or two. A margin of 5 degrees or more is comfortable, but high humidity can erode it quickly as the night cools, so watch the trend. Q: Do I need a dew heater or just a dew shield? A: A dew shield reduces sky exposure and buys time, often enough on dry nights. On humid nights with a small margin, only a powered dew heater that holds the optics above the dew point reliably prevents condensation. Refractors and corrector plates are especially prone. Q: Does this apply to my camera lens too? A: Yes. Any exposed glass facing the sky behaves the same way, so the dew point and margin apply equally to camera lenses, finder scopes, and eyepieces. Wide front elements with a clear sky view dew fastest. #### Distance to Horizon Calculator URL: https://geratools.com/distance-to-horizon-calculator Calculate the distance to the visible and radar horizon from any observer height above sea level, with refraction correction, and the combined range at which a target of known height comes into view. Built for mariners and coastal lookouts. How to use: 1. Enter your eye height: Type the height of your eye above sea level in metres, for example the bridge wing height on a ship or your standing height on a beach. 2. Add the target height: Optionally enter the height of a distant object such as a lighthouse or another vessel to compute the combined range at which it appears. 3. Read the horizon ranges: The tool shows the geometric horizon, the refraction-corrected visible horizon, the radar horizon, and the combined geographic range to the target. FAQ: Q: Why are there three different horizon distances? A: The geometric horizon ignores the atmosphere. The visible horizon adds terrestrial refraction, which bends light around the curve and extends the range. The radar horizon uses a larger refraction factor because radio waves bend more, so radar sees slightly farther than the eye. Q: What formula is used? A: The visible horizon in nautical miles is about 2.08 times the square root of eye height in metres. The radar horizon uses 2.23 times the square root of height. The geometric value uses 1.93. Each constant bakes in the Earth's radius and a refraction coefficient. Q: How do I find when a lighthouse appears? A: The geographic range is the sum of your horizon distance and the object's horizon distance. The tool adds the visible-horizon range for your eye height to that of the target height, giving the distance at which the object dips above or below the horizon. Q: Does this account for the height of the chart light? A: This computes geographic range based on Earth curvature and refraction only. A charted light also has a luminous range limited by intensity. The actual sighting range is the lesser of the geographic and luminous ranges. Q: Why metres and nautical miles? A: Charts and marine practice work in metres for height and nautical miles for distance. The constants in the formula are tuned for those units, so heights go in as metres and all ranges come out in nautical miles. #### Dividing Head Calculator URL: https://geratools.com/dividing-head-calculator For a standard 40:1 dividing head, calculate the crank turns and hole-circle setting needed to index any number of divisions from 2 to 400. Identifies a matching Brown & Sharpe or Cincinnati index plate, the hole circle, and the spaces to advance. How to use: 1. Enter the number of divisions: Type how many equal divisions you need to cut around the workpiece, from 2 to 400. 2. Read the crank turns: The tool computes the turns of the index crank as 40 divided by your division count, splitting it into whole turns plus a fractional part. 3. Set the hole circle: The tool finds an index-plate hole circle that expresses the fraction exactly, telling you which plate, which circle, and how many holes to advance per division. FAQ: Q: Why is the constant 40? A: Standard dividing heads use a 40 to 1 worm-and-wheel ratio, so 40 turns of the index crank rotate the spindle one full revolution. To cut N equal divisions you advance the crank 40 divided by N turns for each division. Q: How is the hole circle chosen? A: The fractional part of 40/N must be expressed as a whole number of holes on an available circle. The tool searches standard Brown & Sharpe and Cincinnati hole circles for one whose hole count is a multiple of the fraction's denominator, then scales the numerator to match. Q: What is the sector arm for? A: The sector arms are set to span the number of holes you advance each division so you do not have to count holes every time. Set the arms to the computed spaces, and after each cut swing the crank to the next arm position. Q: What if no plate gives an exact division? A: Some prime divisions above 50, such as 53 or 59, cannot be done by simple indexing on standard plates and require differential indexing with change gears or angular approximation. The tool reports when a division is not achievable by simple indexing. Q: Do the holes counted include the starting hole? A: No. The count is the number of spaces, or gaps, to advance, not holes touched. Advancing 9 holes on a 15-hole circle means moving past 9 gaps from your current hole, which the sector arms enforce automatically. #### Fetal Growth Centile Calculator (INTERGROWTH-21st) URL: https://geratools.com/fetal-growth-centile-calculator Calculate an estimated fetal weight centile from ultrasound EFW and gestational age using the INTERGROWTH-21st international standard, with z-score, median weight, and small (SGA, under 10th) or large (LGA, over 90th) classification. How to use: 1. Enter estimated fetal weight: Type the ultrasound-derived estimated fetal weight in grams. The EFW standard is defined from 22 to 40 weeks. 2. Enter gestational age: Enter completed weeks and any extra days from 0 to 6, so the centile is matched to the precise gestational age. 3. Read the centile: The tool returns the centile, the median weight for that age, a z-score, and an SGA or LGA classification. FAQ: Q: What standard does this use? A: It uses the INTERGROWTH-21st international estimated fetal weight standard published by Stirnemann and colleagues in 2017, which models the logarithm of EFW as a function of gestational age. It is a prescriptive international standard rather than a local reference. Q: What counts as SGA and LGA? A: A centile below the 10th is classified small for gestational age (SGA) and above the 90th is large for gestational age (LGA). Between the 10th and 90th centiles the weight is appropriate for gestational age (AGA). Q: Is a single low centile a diagnosis of growth restriction? A: No. A single estimate below the 10th centile flags a small fetus but does not by itself diagnose fetal growth restriction. Serial measurements showing a falling trajectory, abnormal Dopplers, and the clinical context are needed for that judgement. Q: How accurate is an estimated fetal weight? A: Ultrasound EFW typically carries a margin of about plus or minus 10 to 15 percent, so the centile inherits that uncertainty. Use it as a screening figure alongside the trend across scans rather than a precise weight. Q: What gestational age range is valid? A: The INTERGROWTH-21st EFW standard is defined from 22 to 40 completed weeks. Outside that window the tool will not return a centile because the published equation does not cover it. #### FPV Video Frequency Channel Planner URL: https://geratools.com/fpv-frequency-channel-planner Select the number of pilots and the 5.8 GHz video band to get a non-overlapping channel assignment with safe frequency spacing. Built on the IMD-tested race channel sets so multiple FPV pilots can fly at once without video interference. How to use: 1. Enter the number of pilots: Type how many pilots will fly at the same time, from 1 up to 8. The planner picks a tested set with the widest possible spacing. 2. Review the assigned channels: Each pilot gets a band, channel and exact frequency in MHz. Channels are chosen from interference-tested sets such as IMD5 and the standard 8-pilot Raceband. 3. Set each VTX and confirm spacing: Set each pilot's video transmitter to the listed band and channel. The minimum gap between any two pilots is shown so you can confirm clean separation. FAQ: Q: Why can't pilots just pick any channels? A: Video transmitters that are close in frequency, or whose harmonics interact, cause intermodulation distortion (IMD) — visible static and breakup even when neither pilot is on the exact same channel. Tested channel sets like IMD5 are specifically chosen so the spacings and harmonics do not interfere, allowing several pilots to fly cleanly at once. Q: What is the IMD5 channel set? A: IMD5 is a widely used five-pilot 5.8 GHz set (Raceband 1, 2, 4, 7, 8 — 5658, 5695, 5769, 5880, 5917 MHz) chosen so the frequencies are spaced far enough apart and their intermodulation products fall outside the video bandwidth. It is the de facto standard for five-pilot heats at FPV races. Q: How far apart should FPV channels be? A: A practical rule of thumb is at least 37-40 MHz of separation between adjacent pilots on 5.8 GHz analog, and ideally more. Standard analog video occupies roughly 20-30 MHz of bandwidth, so closer spacing causes one pilot's signal to bleed into another's. This planner reports the minimum spacing in its chosen set so you can verify it. Q: Does antenna polarisation help? A: Yes. Even with good frequency separation, keeping all pilots on the same antenna polarisation (for example all right-hand circular) is standard practice, because mixing polarisations does not reliably isolate channels and can worsen multipath. Frequency planning and matched antennas work together. Q: Can I fly more than eight pilots at once? A: On a single 5.8 GHz analog band, eight is the practical maximum using the full Raceband, and even then spacing is tight. For larger events, organisers split pilots across separate flying areas or use digital systems with managed spectrum. This planner caps at eight, the limit for clean analog Raceband flying. #### Aircraft Fuel Burn & Endurance Calculator URL: https://geratools.com/fuel-burn-endurance-calculator Compute flight endurance, usable range, and the 30 or 45 minute VFR/IFR reserve from fuel burn rate, usable fuel quantity, and true airspeed. Pilots use it during preflight fuel planning to confirm legal reserves remain. Runs in your browser. How to use: 1. Enter usable fuel and burn rate: Type the usable fuel on board and the cruise fuel burn rate per hour, both in the same units of gallons or litres. 2. Add your cruise speed: Enter your true airspeed, or groundspeed if you have a wind estimate, in knots so the tool can turn endurance into range. 3. Choose the reserve: Pick the 30 minute day VFR or 45 minute night VFR and IFR reserve, and read the endurance and range remaining once that reserve is set aside. FAQ: Q: What reserve fuel is legally required? A: Under common day VFR rules you must land with at least 30 minutes of fuel at normal cruise burn, and 45 minutes for night VFR or IFR. The tool subtracts the reserve you select from usable fuel before computing the endurance and range you can actually plan to. Q: Should I plan to tanks-dry endurance? A: Never. Tanks-dry endurance is shown only as a reference. Always plan your flight to the endurance and range remaining after the reserve, and add allowances for taxi, climb, and any unusable fuel your aircraft cannot draw. Q: What units should I use? A: Use whatever unit your aircraft documents, gallons or litres, as long as usable fuel and burn rate share the same unit. The range output is in nautical miles because the speed input is in knots. Q: Should I use true airspeed or groundspeed? A: Use true airspeed for a still-air estimate, or groundspeed if you have applied a wind correction. A headwind lowers groundspeed and therefore range, so for the binding leg of a flight use the groundspeed you expect on that heading. Q: Why did the tool warn that reserve exceeds fuel? A: If your usable fuel is less than the required reserve, there is no legal fuel to fly any distance and the warning appears. You must add fuel, choose a shorter reserve category if eligible, or not depart with that load. #### Glide Distance Calculator URL: https://geratools.com/glide-distance-calculator Calculate maximum power-off glide range from your height above the landing site and best-glide ratio, with a head and tailwind correction and the time available before touchdown. A training aid for engine-failure decision making. How to use: 1. Enter your height: Type your height above the intended landing site in feet AGL, not your altitude above sea level. 2. Enter the glide ratio and sink rate: Enter the aircraft best-glide ratio and the sink rate at best-glide speed so the tool can compute range and time aloft. 3. Add the wind and read the range: Enter the wind component along your glide path, then read still-air range, ground range, and the minutes available. FAQ: Q: How is glide range calculated? A: Glide range in still air equals your height multiplied by the glide ratio. A 9:1 ratio means the aircraft travels 9 ft forward for every 1 ft of descent, so 5,000 ft of height gives 45,000 ft, about 7.4 nautical miles, of still-air range. Q: What is a glide ratio? A: The glide ratio, or lift-to-drag ratio, is how far the aircraft travels horizontally for each unit of altitude lost with the engine off. Light singles are often around 8:1 to 10:1, gliders 30:1 or more. It is achieved only at the published best-glide speed. Q: How does wind change the range? A: A headwind blows the aircraft backward relative to the ground during the glide, shortening ground range; a tailwind extends it. The tool subtracts the wind speed multiplied by the minutes aloft, so a strong headwind can cost you a mile or more. Q: Why is the real glide shorter than the calculation? A: The figure assumes a steady best-glide speed in a straight line. Every turn, any speed faster or slower than best glide, and configuration drag all increase sink and cut range. Always plan to arrive over the field with height in reserve. Q: What sink rate should I use? A: Use the descent rate at best-glide speed, which the POH or a quick test flight provides. It only affects the time-aloft figure, not the range; range depends on the glide ratio and your height above the site. #### Hat Size Conversion Chart URL: https://geratools.com/hat-size-chart Convert hat sizes across US fractional, UK fractional, EU numeric, and S/M/L systems using head circumference. Measure around your head and read every matching size, or browse the full reference table for fitted and adjustable hats. Runs in your browser. How to use: 1. Measure your head: Wrap a tape measure around your head about a centimetre above your ears and eyebrows, where a hat would naturally sit. Record the circumference in centimetres or inches. 2. Enter the measurement: Type the head circumference into the lookup box and pick your unit. The tool finds the nearest standard size. 3. Read every size: The closest row is highlighted, showing the US, UK, and EU sizes plus the S/M/L band for adjustable hats. FAQ: Q: How do I measure my head for a hat? A: Wrap a soft tape measure around the largest part of your head, roughly one centimetre above your ears and eyebrows, which is where most hats rest. Keep the tape level and snug but not tight. The circumference in centimetres or inches drives every hat size system. Q: Why are US and UK hat sizes different? A: US and UK fitted hat sizes are both based on head diameter in inches but round differently, so a US 7 1/8 is a UK 7. The EU system uses the head circumference in centimetres directly, so an EU 57 hat fits a 57 cm head. This chart aligns all three. Q: What is the formula behind fitted hat sizes? A: Fitted hat size equals the head circumference in inches divided by pi, giving an effective head diameter. A 22.4 inch circumference divided by 3.1416 is about 7.1 inches, which rounds to a US 7 1/8 hat. EU sizing skips this and uses the raw circumference in centimetres. Q: What if my head is between two sizes? A: For fitted hats, round up to the next size for comfort, then use the internal sizing tape or foam inserts to fine-tune. For S/M/L adjustable hats, choose the band your measurement falls into; the strap or snapback handles small differences. Q: Are stretch and structured hats sized the same? A: No. Stretch-fit and knit hats run smaller and pull to fit a range, so go by their stated S/M/L range. Structured fitted caps and formal hats follow the exact numeric sizing in this chart, so measure carefully for those. #### IATA Live Animal Regulations Quick Reference URL: https://geratools.com/iata-live-animal-regulations-reference Browse an embedded quick reference of IATA Live Animals Regulations container categories, ventilation and construction requirements, and the document checklist for common species groups (dogs, cats, horses, birds, fish). Built for freight forwarders and airline acceptance staff validating bookings. How to use: 1. Pick a species group: Select the animal category you are shipping — dogs and cats, horses, birds, or fish and aquatics — to load its container and document profile. 2. Review container and ventilation rules: Read the applicable IATA Container Requirement, the key construction and ventilation points, and the minimum-space rule for that species group. 3. Work the document checklist: Tick off each required document for the shipment so you can confirm the booking is complete before tendering it to the airline. FAQ: Q: Is this a substitute for the official IATA LAR manual? A: No. The IATA Live Animals Regulations is the binding standard and is updated annually; this is a quick-reference summary to help you plan and sanity-check a booking. Always confirm the current Container Requirement and species rules in the live LAR edition before tendering. Q: What is a Container Requirement (CR) number? A: The LAR assigns each species group a Container Requirement number, such as CR 1 for dogs and cats, specifying the crate's construction, ventilation, door, and feeding-and-watering arrangements. Acceptance staff check the crate against the CR for the species. Q: How much space must an animal have in its container? A: The general rule is the animal must be able to stand, turn around, and lie down in a natural position without touching the sides or top. For dogs and cats, length is measured nose-to-tail-base and height is the standing height to the top of the head or ear tips. Q: What documents are typically required? A: Most live-animal air shipments need a Shipper's Certification for Live Animals, an air waybill, a health or veterinary certificate, an import permit where required, and the IATA marking and labelling on the container. Species and destination add further permits such as CITES. Q: Does ventilation depend on the species? A: Yes. Each Container Requirement specifies minimum ventilation openings on multiple sides of the crate, and warm-blooded animals need more open area than the minimum for short-haul. Birds and small mammals have specific opening sizes to prevent escape while ensuring airflow. #### IBU Rager Calculator URL: https://geratools.com/ibu-rager Applies Jackie Rager's hop utilization table to compute IBUs per addition from boil time, alpha acid, hop weight, batch volume, and gravity. Predicts higher bitterness than Tinseth at shorter boil times. How to use: 1. Enter your wort details: Set the batch volume and the boil gravity (the gravity during the boil, not the final OG). The calculator uses gravity above 1.050 to apply a correction. 2. Add each hop addition: For every hop, enter the weight, its alpha acid percentage, and the boil time. The Rager utilization table converts boil time into a percentage of alpha acid extracted. 3. Read the total IBU: Each addition's IBU is summed into a total. Compare it to your target style range and adjust hop weights or times to hit your balance. FAQ: Q: How does the Rager formula differ from Tinseth? A: Rager uses a stepwise utilization table that rises steeply in the first 30 minutes, so it predicts noticeably higher IBUs than Tinseth for short boils. Rager also applies a gravity-adjustment penalty only above 1.050, while Tinseth uses a continuous gravity factor across the whole range. Q: What is the gravity adjustment for? A: Higher-gravity worts are more viscous and reduce hop isomerization. Rager subtracts a correction when boil gravity exceeds 1.050: GA = (boil gravity − 1.050) ÷ 0.2. This is added to the volume term in the denominator, lowering the calculated IBU. Q: Should I use boil gravity or original gravity? A: Use the gravity during the boil. With late top-up water or full-volume boils this may equal your OG, but partial-boil brewers should estimate the concentrated boil gravity, which is higher and therefore lowers utilization. Q: Why are my IBUs higher than my brewing software? A: Most modern software defaults to Tinseth, which generally yields lower numbers. Rager was the early standard and runs hotter, especially for flameout and short additions. Neither is wrong — they are different models; pick one and stay consistent. Q: Does this account for whirlpool or dry hops? A: No. The Rager model is built for boil additions only. Dry hops contribute essentially zero measurable IBU, and whirlpool/hop-stand bitterness is highly variable and not part of the original Rager table. #### IBU Tinseth Calculator URL: https://geratools.com/ibu-tinseth Calculate beer bitterness (IBU) with Glenn Tinseth's utilization formula from alpha-acid percentage, hop weight, boil time, wort gravity, and batch volume. Supports multiple hop additions and sums the total. The most popular IBU method for homebrewers. Runs in your browser. How to use: 1. Set the boil gravity and volume: Enter the gravity of the wort during the boil and your batch volume in litres. Higher gravity lowers hop utilization. 2. Add each hop addition: For every hop, enter the weight in grams, its alpha-acid percentage, and how many minutes it boils. Add as many additions as your recipe needs. 3. Read the total IBU: Each addition's contribution is shown on its row, and the panel below totals them into the final bitterness in IBU. FAQ: Q: What is the Tinseth formula? A: Glenn Tinseth's formula estimates IBU from hop utilization: IBU = utilization × (AA% × weight × 1000) ÷ (volume × 10). Utilization is the bigness factor times the boil-time factor, which model how gravity and boil time affect alpha-acid isomerization. Q: How does wort gravity affect bitterness? A: Higher-gravity wort extracts fewer bittering compounds, so utilization drops. The bigness factor is 1.65 × 0.000125^(gravity − 1), which lowers IBU as your boil gravity rises above 1.050. Q: Why does longer boiling increase IBU? A: Alpha acids must isomerize in the boil to taste bitter, and that takes time. The boil-time factor (1 − e^(−0.04 × minutes)) ÷ 4.15 rises steeply early then plateaus, so 60-minute additions give most of the bitterness. Q: Should I use whole-cone or pellet weight? A: Enter the weight you actually add. Pellets are slightly more efficient than whole cones, but Tinseth uses a single utilization model; most brewers accept this and adjust by taste over successive batches. Q: Is my recipe data uploaded? A: No. The whole calculation runs locally in your browser and nothing is sent to a server. #### METAR Decoder URL: https://geratools.com/metar-decoder Paste a raw METAR and get a field-by-field plain-English translation of station, time, wind, visibility, weather, sky, temperature, dewpoint, and altimeter. Student pilots and non-aviators use it to read aeronautical weather reports. Runs in your browser. How to use: 1. Paste the raw METAR: Copy the METAR string from an aviation weather service and paste it into the box. The decoder works with or without the leading METAR keyword. 2. Read the breakdown: Each field is shown with the original code, a label, and a plain-English translation, so you can see exactly what every group means. 3. Check unparsed groups: Any group the decoder cannot recognise is flagged in red. These are usually remarks or local codes you can look up separately. FAQ: Q: What is a METAR? A: A METAR is a routine aviation weather observation issued by an airport, usually every hour. It packs current wind, visibility, weather, cloud, temperature, and pressure into a compact coded string that this tool translates into readable sentences. Q: What time zone is the report in? A: The day-and-time group ends in Z, meaning it is in UTC, also called Zulu time. The first two digits are the day of the month and the next four are the hour and minute, so 121956Z is the 12th at 19:56 UTC. Q: What does CAVOK mean? A: CAVOK stands for ceiling and visibility OK. It means visibility is 10 kilometres or more, there is no cloud below 5,000 feet or below the highest minimum sector altitude, no cumulonimbus, and no significant weather. The decoder expands it for you. Q: How are wind gusts shown? A: A wind group like 28012G18KT means the wind is from 280 degrees at 12 knots gusting to 18 knots. The decoder breaks out the direction, steady speed, and gust separately so the values are unambiguous. Q: Why are some groups not decoded? A: Anything after the RMK keyword is a remarks section that often contains automated or country-specific coding, which the decoder shows raw. A genuinely unrecognised group before remarks is flagged so you can verify it against an official source. #### Metric–Imperial Conversion Reference URL: https://geratools.com/metric-imperial-conversion-reference Reference of exact metric-to-imperial conversion factors for length, mass, volume, and temperature, with a live two-way converter that applies each factor and handles the temperature offset correctly. How to use: 1. Pick a conversion: Choose a unit pairing such as inches and centimetres from the selector. 2. Enter a value: Type a number in either box; the other side updates automatically using the exact factor. 3. Check the factor: The reference table lists the exact multiplier for each pairing, with temperature handled by its offset formula. FAQ: Q: Which conversion factors are exact rather than approximate? A: Several are defined exactly: 1 inch equals 2.54 cm, 1 pound equals 0.45359237 kg, 1 US gallon equals 3.785411784 litres, and 1 mile equals 1.609344 km. These were fixed by international agreement, so they are not rounded approximations but definitions. Q: Why is temperature conversion different from the others? A: Length, mass, and volume conversions are simple multiplications because their zero points coincide. Temperature scales have different zero points, so converting Celsius to Fahrenheit needs both a scale factor of 9/5 and an offset of 32 degrees: F equals C times nine fifths plus thirty-two. Q: Is a US gallon the same as a UK gallon? A: No. A US liquid gallon is about 3.785 litres, while a UK (imperial) gallon is about 4.546 litres, roughly 20 percent larger. This reference uses US gallons for volume; always confirm which gallon a recipe or spec means, especially for fuel economy figures. Q: What is the difference between mass and weight in these conversions? A: Strictly, the kilogram and pound here are units of mass, and the conversion 1 lb equals 0.4536 kg is a mass equivalence. In everyday use weight and mass are treated as interchangeable on Earth's surface, which is fine for cooking and shipping but not for physics calculations involving gravity. Q: How precise are the results shown? A: The tool computes with full double-precision factors and rounds the displayed result to a sensible number of digits. For engineering or legal use, apply the exact factor yourself and round only at the final step to avoid accumulated rounding error. #### Number System Conversion Reference URL: https://geratools.com/number-system-conversion Convert any number between decimal, binary, octal, and hexadecimal, with a full reference table of values 0 to 255 in all four bases. Fast, accurate, and fully private. How to use: 1. Enter a value: Type the number you want to convert into the value field. 2. Pick its base: Select whether your input is decimal, binary, octal, or hexadecimal. 3. Read all four bases: The result panel shows the same value in decimal, binary, octal, and hex instantly. FAQ: Q: How does base conversion actually work? A: Every number is the sum of its digits times powers of the base. To convert to another base you repeatedly divide by the new base and read the remainders in reverse. The reference table below shows this for 0 to 255. Q: What is the difference between octal and hexadecimal? A: Octal is base 8 (digits 0 to 7) and hexadecimal is base 16 (digits 0 to 9 then A to F). Octal groups bits in threes, hex groups them in fours, which is why one hex digit equals exactly four binary digits. Q: Why does the table pad with leading zeros? A: The table pads binary to 8 bits, octal to 3 digits, and hex to 2 digits so values line up as a single byte. This makes it easy to read a byte value in any base at a glance. Q: Can I convert hexadecimal letters like A to F? A: Yes. Choose hexadecimal as the input base and type digits 0 to 9 and letters A to F (case does not matter). The converter validates that every character is legal for the chosen base. Q: Is my data sent anywhere? A: No. All conversion happens in your browser using local arithmetic. Nothing you type is uploaded or stored. #### OECD Pillar Two Global Minimum Tax Calculator URL: https://geratools.com/oecd-pillar-two-top-up-tax Enter jurisdiction-level revenue, profit, and effective tax rate to estimate top-up tax under the OECD Pillar Two GloBE rules. Applies the substance-based income exclusion carve-outs for payroll and tangible assets, and handles the QDMTT offset. For multinational enterprise tax teams. How to use: 1. Enter jurisdiction figures: Input the GloBE income (profit), covered taxes, eligible payroll, and tangible asset book value for the jurisdiction. 2. Select the fiscal year: The year sets the transitional substance-based income exclusion rates, which step down annually toward the steady-state 5%. 3. Read the top-up tax: The tool computes the effective tax rate, the top-up percentage, the SBIE carve-out, and the final top-up tax payable. FAQ: Q: What is the OECD Pillar Two top-up tax? A: Pillar Two ensures large multinational groups pay an effective tax rate of at least 15% in every jurisdiction. Where the local effective rate falls below 15%, a top-up tax is charged to bring it up to the minimum, calculated under the GloBE rules. Q: How is the effective tax rate computed? A: The GloBE effective tax rate is covered taxes divided by GloBE income for the jurisdiction, expressed as a percentage. The top-up percentage is the shortfall between 15% and that rate, applied to excess profit. Q: What is the substance-based income exclusion? A: The SBIE carves out a routine return on real activity from the top-up base: a percentage of eligible payroll plus a percentage of tangible asset book value. Transitional rates start at 9.8% payroll and 7.8% assets in 2024 and step down to 5% each by 2033. Q: What does QDMTT do? A: A Qualified Domestic Minimum Top-Up Tax lets a jurisdiction collect its own top-up tax locally. Where a QDMTT applies, it reduces the top-up otherwise collectable by the parent under the Income Inclusion Rule to nil, so the revenue stays in the source country. Q: Is this a filed computation? A: No. This is a simplified planning estimate. The full GloBE computation includes deferred-tax adjustments, the de-minimis exclusion, blended entities, and the GloBE Information Return. Use a qualified adviser for actual filings. #### Planet Altitude & Azimuth Calculator URL: https://geratools.com/planet-altitude-azimuth-calculator Using Keplerian orbital elements with secular rates, calculate the altitude and azimuth of solar system planets for a given observer latitude, longitude, date, and time. For visual and imaging astronomers planning observing sessions. How to use: 1. Set your location: Enter your observing latitude and longitude in decimal degrees (east longitude positive, west negative). 2. Set the date and time: Enter the UTC date and time you plan to observe, or convert your local clock time to UTC first. 3. Pick a planet: Choose a planet and read its computed altitude above the horizon and azimuth (compass bearing), plus whether it is currently up. FAQ: Q: How does this calculate a planet's position? A: It uses Keplerian orbital elements with secular rates for each planet and Earth, solves Kepler's equation for the eccentric anomaly, finds heliocentric positions, takes the geocentric vector to the planet, converts ecliptic to equatorial coordinates, then to local horizontal alt/az using the observer's location and sidereal time. Q: What do altitude and azimuth mean? A: Altitude is the angle above the horizon, from 0 degrees at the horizon to 90 degrees at the zenith; negative means below the horizon and not visible. Azimuth is the compass bearing measured clockwise from north, so 90 degrees is east, 180 is south, and 270 is west. Q: How accurate is this calculator? A: The truncated Keplerian model is accurate to roughly a few arcminutes for the inner planets and within about a tenth of a degree for the outer planets over the years around 2000 to 2050. That is far more than enough to point a telescope or plan a session, though it is not a precision ephemeris. Q: Why must I use UTC instead of local time? A: Sidereal time and orbital positions are computed from a universal clock, so the tool needs UTC to be unambiguous across time zones and daylight saving. Convert your local civil time to UTC by adding or subtracting your zone offset before entering it. Q: Why is the altitude negative for the planet I want? A: A negative altitude means the planet is below your horizon at that moment and cannot be seen. Try a different time of night, or check when it rises; planets near the sun in the sky may only be up briefly after sunset or before dawn. #### Pump Total Dynamic Head (TDH) Calculator URL: https://geratools.com/pump-head-calculator Compute pump total dynamic head by summing static lift, Hazen-Williams friction loss with bundled C-factor tables, fitting losses as equivalent length, and velocity head. Built for plumbers and mechanical engineers selecting booster, transfer, and circulation pumps. How to use: 1. Enter static head and flow: Type the total vertical lift plus any required pressure rise as static head, and the design flow rate in US gallons per minute. 2. Add the pipe details: Enter the inside diameter, straight pipe length, the equivalent length of all fittings, and select the pipe material to set the Hazen-Williams C factor. 3. Read the total dynamic head: The tool breaks out static head, friction loss, and velocity head, then sums them into the TDH you size the pump against. FAQ: Q: What is total dynamic head? A: Total dynamic head (TDH) is the total resistance a pump must overcome: the static lift, the friction loss through pipe and fittings, and the velocity head. It is the value you match against a pump's performance curve at your design flow. Q: How is friction loss calculated? A: This tool uses the Hazen-Williams equation, the standard for water at normal temperatures. Loss grows with flow raised to the 1.852 power and falls steeply with diameter, so small pipes and high flows dominate the friction term. Q: What is equivalent length of fittings? A: Each elbow, tee, and valve adds resistance equal to a length of straight pipe. Adding that total equivalent length to the actual pipe length lets the friction formula account for all the fittings at once. Q: What pipe velocity should I target? A: Keep velocity under roughly 5 ft/s on the suction side and 8 ft/s on the discharge to limit noise, erosion, and water hammer. The tool warns when velocity exceeds 8 ft/s so you can step up a pipe size. Q: Does TDH change with flow? A: Yes. Static head is fixed, but friction and velocity head climb sharply with flow. That is why a pump and pipe are sized together as a system operating point, not in isolation. #### Refractometer FG Correction Calculator URL: https://geratools.com/refractometer-correction Apply the Sean Terrill correction to convert post-fermentation refractometer Brix readings into true final gravity, accounting for alcohol's effect on refractive index. Also estimates ABV. Runs in your browser. How to use: 1. Enter your original Brix: Type the refractometer Brix reading you took of the unfermented wort before pitching yeast. 2. Enter your final Brix: After fermentation, read the beer on the same refractometer and enter that Brix value. 3. Set the wort correction factor: Most refractometers need a small correction (around 1.04) because wort refracts differently from sucrose. Read the corrected FG and estimated ABV. FAQ: Q: Why can't I read FG directly off a refractometer? A: A refractometer measures refractive index, which alcohol also affects strongly. Once fermentation produces ethanol, the raw Brix reading no longer maps to gravity, so a correction formula is needed to back out the alcohol's contribution and recover true final gravity. Q: What is the wort correction factor (WCF)? A: Refractometers are calibrated against sucrose solutions, but wort sugars refract slightly differently. The WCF divides your readings to compensate; for most worts it falls between 1.02 and 1.06, with 1.04 a common default. Calibrate yours against a hydrometer for best accuracy. Q: Which correction formula does this use? A: It uses the Sean Terrill cubic correction, a widely-adopted empirical fit that takes corrected original and final Brix and returns final gravity. It is generally accurate to within a few gravity points for normal-strength beers. Q: How is ABV estimated from the corrected gravity? A: Once original gravity and corrected final gravity are known, ABV is estimated with the standard formula ABV ≈ (OG − FG) × 131.25. This is the same approximation used by most homebrew calculators and is accurate for typical beer strengths. Q: Is a hydrometer more accurate for final gravity? A: A hydrometer reads final gravity directly with no alcohol correction needed, so it is the gold standard for FG. Refractometers are convenient because they need only a drop or two of sample; the correction formula makes them usable, but cross-check important readings with a hydrometer. #### Self-Employment Tax Calculator (2026) URL: https://geratools.com/self-employment-tax-calculator-2026 Calculate your 2026 self-employment tax — 12.4% Social Security on net earnings up to the $176,100 wage base plus 2.9% Medicare with no cap, computed on 92.35% of net profit. Shows total SE tax and the deductible employer-equivalent half. How to use: 1. Enter your net profit: Type your net profit from self-employment (Schedule C net income) — gross receipts minus business expenses. 2. Add any W-2 wages: If you also had a W-2 job, enter the wages already subject to Social Security so the calculator reduces your remaining $176,100 wage base. 3. Read your SE tax: See net earnings (92.35% of profit), the Social Security and Medicare portions, total SE tax, and the deductible employer-equivalent half. FAQ: Q: How is 2026 self-employment tax calculated? A: SE tax is computed on 92.35% of your net profit. That base is taxed 12.4% for Social Security up to the $176,100 wage base and 2.9% for Medicare with no cap. On $80,000 of net profit, net earnings are $73,880, and SE tax is $11,303. Q: Why is only 92.35% of my profit taxed? A: The 7.65% reduction mirrors the employer-side payroll deduction an employee would not pay tax on. Multiplying net profit by 0.9235 gives the net earnings figure that Schedule SE actually taxes, so a $100,000 profit is assessed on $92,350. Q: How does a W-2 job affect my SE tax? A: Social Security tax stops at a combined $176,100 of wages plus net earnings. If your W-2 already paid Social Security on $100,000, only $76,100 of your self-employment net earnings can still be hit by the 12.4% Social Security portion; the 2.9% Medicare portion still applies to all of it. Q: Can I deduct part of my self-employment tax? A: Yes. You deduct the employer-equivalent half of SE tax as an above-the-line adjustment to income. On an $11,303 SE tax bill, you deduct $5,652, which lowers your income tax even though it does not reduce the SE tax itself. #### TAF Decoder URL: https://geratools.com/taf-decoder Paste a raw TAF and get a chronological plain-English breakdown of the prevailing forecast plus FM, BECMG, TEMPO, and PROB change groups. Pilots and operations staff use it to assess departure, alternate, and destination conditions. Runs in your browser. How to use: 1. Paste the raw TAF: Copy the full TAF from an aviation weather source and paste it in. The decoder accepts the report with or without the leading TAF keyword. 2. Read the timeline: The forecast is split into the header, the prevailing forecast, and each change group, with the validity period and a plain-English decode for every element. 3. Plan around change groups: Pay attention to FM, BECMG, TEMPO, and PROB groups, which tell you when and how the conditions are expected to change during the validity period. FAQ: Q: What is the difference between a TAF and a METAR? A: A METAR is an observation of current weather, while a TAF is a forecast of expected conditions at an aerodrome, typically valid for 24 or 30 hours. The TAF uses similar codes but adds change groups describing how conditions evolve over time. Q: What do FM, BECMG, and TEMPO mean? A: FM marks a rapid and lasting change from a specific time. BECMG describes a gradual change expected to occur within a window and then persist. TEMPO describes temporary fluctuations lasting under an hour at a time that are not expected to dominate the period. Q: What does a PROB group mean? A: PROB followed by a number, such as PROB30, gives the percent probability that the described conditions will occur during the stated window. It is used for significant but uncertain weather like thunderstorms, and the decoder labels the probability for you. Q: How do I read the validity period? A: The validity group such as 1218/1324 means the forecast runs from the 12th at 18:00 UTC to the 13th at 24:00 UTC. Each change group also carries its own period showing when that variation applies within the overall forecast. Q: Does P6SM mean the same as 10SM? A: P6SM means visibility greater than 6 statute miles and is the standard way North American TAFs report unlimited visibility, since 6 miles is the threshold above which exact values are not forecast. The decoder expands it to plain language. #### Telegram Hashtag Limit Helper URL: https://geratools.com/telegram-hashtag-limit-helper Paste your post text and this tool extracts every hashtag, counts them, flags invalid tags, shows total character cost, and warns when you exceed the recommended hashtag count for a clean, discoverable Telegram post. How to use: 1. Paste your post: Drop your full Telegram post text, including all the hashtags, into the box. 2. Review the audit: The tool lists every hashtag it found, counts them, validates each, and totals their character cost. 3. Trim to the sweet spot: If you are over the recommended count or any tag is invalid, edit and re-paste until everything is clean. FAQ: Q: How many hashtags can a Telegram post have? A: Telegram does not impose a hard numeric cap on hashtags, but readability and discoverability suffer past a handful. The widely used guideline is 1 to 3 focused hashtags per post; this tool warns once you exceed 3 so your post stays clean and clickable. Q: What makes a Telegram hashtag valid? A: A valid Telegram hashtag starts with # followed by letters, digits, or underscores with no spaces or punctuation inside. Tags containing spaces, hyphens, or symbols break the link, so this tool flags them as invalid. Q: Do hashtags count toward the message character limit? A: Yes. Every hashtag, including the # symbol, counts toward Telegram's 4096-character message limit or 1024-character caption limit. This helper totals the character cost of all your hashtags so you can budget the rest of your copy. Q: Are Telegram hashtags case-sensitive? A: Telegram treats hashtag search as case-insensitive for matching, but the tag displays exactly as you type it. Mixing cases like #TelegramTips is fine for readability and still matches #telegramtips when people search. Q: Why does my hashtag not turn into a link? A: A hashtag only becomes a clickable link when it is immediately preceded by whitespace or the start of the line and contains only valid characters. A # stuck to the end of another word, or one with punctuation inside, will not link — this tool catches those cases. #### Telegram Profile & Banner Size Tool URL: https://geratools.com/telegram-profile-banner-size Lookup tool that returns the exact pixel dimensions, safe-crop circles, and recommended export settings for Telegram profile pictures, channel logos, and group photos. Pick a surface and read the right size instantly. Runs in your browser. How to use: 1. Pick the Telegram surface: Choose whether you are sizing a personal profile picture, a channel or group photo, or a chat avatar so the tool shows the right target dimensions. 2. Read the recommended pixels: The tool shows the upload resolution, the displayed size, and the circular safe area where your subject must sit so nothing important is cropped. 3. Export with the listed settings: Export a square image at the upload resolution as JPG or PNG, keep it under the file-size limit, and your art will look crisp on every device. FAQ: Q: What size should a Telegram profile picture be? A: Upload a square image at least 512x512 pixels. Telegram displays the avatar inside a circle, so it crops the corners. A 512x512 source scales cleanly to every avatar slot from tiny chat-list dots up to the full-screen view. Q: Why does Telegram crop my photo into a circle? A: Telegram renders all avatars as circles. The square you upload has its corners hidden by the circular mask. Keep your face or logo within the inscribed circle, roughly the central 90 percent, so nothing important is clipped. Q: Does Telegram have a separate banner image? A: Telegram has no wide cover banner like other networks. The profile and channel photo is the only branded image, shown as a circle in lists and as a full square when tapped. Size for that single square photo. Q: What file format and size limit should I use? A: Use JPG for photos or PNG for logos with flat colour. Telegram accepts large uploads, but keep your avatar under about 5 MB and square so it compresses cleanly. PNG preserves sharp logo edges; JPG is smaller for photographs. Q: Will a small image look blurry? A: Yes. Telegram upscales small images to fill the full-screen view, which looks soft. Always upload at least 512x512, and 1024x1024 is better for retina and tablet screens where the avatar is shown larger. #### TPC & MCTC Calculator URL: https://geratools.com/tpc-mctc-calculator Derive TPC and MCTC from waterplane geometry: LBP, beam, draught, waterplane and block coefficients, and water density. Naval architects and ship officers use this to verify hydrostatic tables and solve ballasting and trim problems. How to use: 1. Enter the principal dimensions: Type LBP, beam, and mean draught in metres, which fix the waterplane area and displaced volume. 2. Add the coefficients and density: Enter the waterplane area coefficient Cw, block coefficient Cb, and water density (1.025 for sea, 1.000 for fresh). 3. Read TPC and MCTC: The tool returns TPC in tonnes per centimetre and MCTC in tonne-metres per centimetre, along with displacement and BM_L. FAQ: Q: What is TPC? A: TPC, tonnes per centimetre immersion, is the mass that must be loaded or discharged to change the mean draught by one centimetre. It equals the waterplane area times water density divided by 100, so a larger or fuller waterplane gives a higher TPC. Q: What is MCTC? A: MCTC, the moment to change trim one centimetre, is the trimming moment in tonne-metres needed to alter the trim by one centimetre. It is found from the displacement and the longitudinal metacentric height, MCTC equals W times GM_L divided by 100 times LBP. Q: Why does MCTC use the longitudinal metacentric height? A: Trim is a rotation about a transverse axis, so it is governed by the longitudinal metacentric height GM_L, which is dominated by the longitudinal BM_L. BM_L is the longitudinal second moment of the waterplane area divided by the displaced volume, and it is very large, which makes ships stiff in trim. Q: How accurate is this estimate? A: TPC is exact given the true waterplane area. MCTC here uses an inertia coefficient to approximate the longitudinal second moment of area, so it is an estimate within a few percent for normal hull forms. Always cross-check against the vessel's hydrostatic tables for operational work. Q: What density should I use? A: Use 1.025 tonnes per cubic metre for standard sea water and 1.000 for fresh water. Brackish or dock water sits in between, so use the measured dock water density when working out fresh water allowance and dock water allowance. #### Twitch Profile & Banner Size Tool URL: https://geratools.com/twitch-profile-banner-size Lookup tool that returns the exact pixel dimensions, file-size caps and recommended export settings for Twitch profile pictures, profile banners, offline video banners, and video-player offline screens. How to use: 1. Pick an asset: Choose the Twitch image you are creating — profile picture, profile banner, or offline video banner. 2. Read the exact spec: The tool shows the recommended upload size, aspect ratio, file-size cap and accepted formats. 3. Export and upload: Match your export to the listed dimensions and stay under the file-size cap before uploading in Creator settings. FAQ: Q: What size should a Twitch profile picture be? A: Twitch recommends a square profile picture of at least 256x256 pixels, displayed as a circle. Files must be JPG, PNG or GIF and stay under 10 MB. Q: What size is a Twitch profile banner? A: The Twitch profile banner that appears across the top of your channel page is recommended at 1200x480 pixels (2.5:1). Keep the file under 10 MB in JPG, PNG or GIF format. Q: What size is the Twitch offline video banner? A: The offline screen shown in your video player when you are not live is 1920x1080 pixels (16:9), matching the player frame. It must be a JPG or PNG under 10 MB. Q: Why is my Twitch profile picture cropped? A: Twitch masks profile pictures into a circle, so square uploads have their corners hidden. Keep your face or logo centred so nothing important falls in the masked corners. Q: Can Twitch banners be animated? A: Profile pictures and banners accept GIF, so they can animate, but the offline video screen is a static JPG or PNG. Keep animated files small to stay under the 10 MB cap and load fast. #### X/Twitter Profile & Banner Size Tool URL: https://geratools.com/twitter-profile-banner-size Lookup tool that returns the exact pixel dimensions, safe-crop guidance, and recommended export settings for X/Twitter profile pictures, the 1500x500 header banner, and in-post images. How to use: 1. Pick the asset: Choose profile picture, header banner, or in-post image to see its exact dimensions. 2. Read the sizes: The tool lists the upload resolution, how X displays it, the aspect ratio, and a safe-crop note. 3. Export and upload: Export at the recommended size and format, keeping key content inside the safe crop, then upload to X. FAQ: Q: What size is an X/Twitter header banner? A: The X header banner is 1500x500 pixels, a 3:1 ratio, up to 5 MB (2 MB for a GIF). The circular avatar overlaps the lower-left corner and your bio buttons cover the bottom strip, so keep important content in the upper-right two-thirds. Q: What size should an X profile picture be? A: Upload a square image at least 400x400 pixels, with 800x800 recommended, under 2 MB. X masks it to a circle, so centre your subject and keep it clear of the corners that get cropped away. Q: Why does my X banner look cropped? A: X displays the 1500x500 banner responsively and overlays your avatar and bio on top of it. Content near the lower-left and bottom edges is hidden behind those elements, which is the most common reason a banner looks cut off. Q: What file formats does X accept for profile images? A: X accepts JPG, PNG, and GIF for both the profile picture and header. Use PNG for crisp logos and text, and keep within the 2 MB avatar and 5 MB header size caps to avoid heavy compression. Q: What size are in-post images on X? A: A 16:9 image at 1600x900 is the cleanest in-timeline ratio with no crop. Square 1200x1200 images expand fully on tap but get centre-cropped in the timeline, so keep key content centred. #### Warehouse Slotting Velocity Tool URL: https://geratools.com/warehouse-slotting-velocity-tool Classify SKUs into A/B/C velocity bands by order frequency using Pareto cumulative share, then map each band to a golden, silver, or bronze ergonomic pick zone. Warehouse engineers use it to plan slotting changes that cut travel and improve picker ergonomics. How to use: 1. List your SKUs and order lines: Enter one SKU per line as a name and its number of order lines or picks over the period, comma or space separated. 2. Set the ABC cut-offs: Choose the cumulative pick share that separates A from B and B from C, defaulting to the classic 80 and 95 percent. 3. Read the slotting plan: The tool ranks SKUs by velocity, assigns A/B/C bands and golden/silver/bronze zones, and shows each band's share of picks. FAQ: Q: What is ABC slotting? A: ABC slotting ranks SKUs by pick velocity and places the fastest movers in the most accessible locations. A items are the small set of SKUs that drive most picks, B items are moderate movers, and C items are slow movers. Slotting A items closest to packing cuts total travel. Q: What is the golden zone? A: The golden zone is the waist-to-shoulder height band directly in front of the picker, reachable without bending or stretching. It gives the fastest, most ergonomic picks, so the highest-velocity A items belong there. Silver and bronze zones are progressively less convenient. Q: How are the A, B, and C bands decided? A: SKUs are sorted from highest to lowest pick count, then a running cumulative share is taken. SKUs falling below the first cut-off, classically 80 percent of picks, are A. Those up to the second cut-off, around 95 percent, are B, and the remaining long tail is C. Q: Why does slotting by velocity reduce travel? A: A small fraction of SKUs typically generate the majority of picks. Placing those few high-velocity items in the closest, golden-zone locations means pickers spend most of their visits in a compact area, sharply reducing the average distance walked per line. Q: How often should slotting be reviewed? A: Velocity shifts with seasonality and product life cycles, so re-slot at least quarterly, and more often for fast-changing assortments. Re-running ABC analysis on recent order data keeps the golden zone filled with what is actually moving now, not last year's winners. #### Watts to Amps Calculator URL: https://geratools.com/watts-to-amps-calculator Convert watts to amps for DC, AC single-phase, and AC three-phase loads using I = W / (V × PF) or I = W / (√3 × V × PF). Includes power factor for inductive loads so you get the real line current for breaker and conductor sizing. How to use: 1. Enter the wattage: Type the load's real power in watts from the device nameplate or specification. 2. Set phase, voltage, and PF: Choose DC, single-phase, or three-phase, enter the voltage, and for AC loads enter the power factor (1.0 for resistive loads). 3. Read the current: The tool returns the line current in amps and shows the formula used so you can verify it. FAQ: Q: What is the watts to amps formula? A: For DC and AC single-phase, I = W ÷ (V × PF). For AC three-phase, I = W ÷ (√3 × V × PF), where PF is the power factor and √3 ≈ 1.732. For purely resistive loads PF is 1.0. Q: Why does power factor appear here but not in kVA to amps? A: Watts is real power, which is only the component doing work. For inductive loads the line current is larger than watts alone implies, so you must divide by the power factor to recover the actual current. kVA is already apparent power, so it needs no PF. Q: What power factor should I use? A: Use 1.0 for resistive loads like heaters and incandescent lamps. Motors and electronic ballasts typically run 0.7 to 0.9; use the nameplate value when available. Guessing too high underestimates the current and can undersize the breaker. Q: Which voltage for three-phase? A: Use the line-to-line voltage (208, 240, 480, or 600 V). The √3 in the formula accounts for the three-phase relationship, so the line-to-neutral voltage would give the wrong answer. Q: Can I use this to size a breaker? A: It gives the operating current. For continuous loads apply the NEC 125% factor and round up to the next standard breaker, and confirm the conductor ampacity with any temperature or bundling derating separately. #### WhatsApp Profile & Banner Size Tool URL: https://geratools.com/whatsapp-profile-banner-size Lookup tool that returns the exact pixel dimensions, circular safe-crop, and recommended export settings for WhatsApp profile photos, group icons, Channel profile pictures, and Business cover images. How to use: 1. Pick the asset: Choose a profile photo, group icon, Channel profile photo, or Business cover image from the dropdown. 2. Read the upload size: The tool shows the recommended upload dimensions, how WhatsApp displays the asset, and its crop shape. 3. Export and centre: Match your canvas to the upload size and centre your subject inside the circular crop so nothing important is clipped. FAQ: Q: What is the best WhatsApp profile photo size? A: Upload a square image of at least 640×640 pixels. WhatsApp masks it into a circle and downsizes it for chat lists, so a sharp square source keeps the circle crisp. The minimum accepted size is around 192×192 pixels. Q: Why does WhatsApp crop my profile picture into a circle? A: WhatsApp displays all profile and group photos as circles, so it masks the corners of your square upload. Roughly the outer 30% of each corner is hidden, which is why you should centre faces and logos rather than placing them near the edges. Q: What size should a WhatsApp group icon be? A: Use the same 640×640 square as a profile photo. The group icon appears as a small circle in the chat list and header, so keep the design simple and high-contrast so it stays legible at tiny sizes. Q: What size is a WhatsApp Channel profile photo? A: A Channel profile photo is a 640×640 square shown as a circle in the Updates tab. Because it is often seen alongside many other Channels, a bold, recognisable logo works far better than a detailed photo. Q: Does WhatsApp have a cover or banner image? A: Personal accounts have no cover banner, but WhatsApp Business profiles support a cover image at roughly 1080×608 pixels in a wide 16:9 shape. Keep text and logos centred because the edges can crop on narrow screens. #### YouTube Safe Zone Guide URL: https://geratools.com/youtube-safe-zone-guide Overlay simulator showing where YouTube places UI elements — title bar, progress controls, end-screen cards, Shorts action rail, captions — so you can confirm your key content falls outside the dead zones before export. How to use: 1. Choose a player view: Select Landscape video for standard 16:9 uploads or Shorts for vertical 9:16 content. 2. Read the overlay zones: The red boxes mark where YouTube draws its own UI — keep logos, faces, and text out of those regions. 3. Frame to the safe area: Position your key content inside the green dashed central safe zone so nothing important is hidden by player chrome. FAQ: Q: Where does YouTube put the progress bar on landscape video? A: On standard 16:9 video the scrubber, time, volume, and settings controls live in the bottom roughly 14 percent of the frame. Keep captions and key text above that band so the controls never cover them. Q: What is the Shorts action rail? A: The action rail is the vertical column of like, comment, share, remix, and sound buttons on the right edge of a Short. It covers roughly the right 16 percent of the screen, so avoid placing important visuals there. Q: Why does my end screen cover part of my video? A: YouTube reserves the upper-right area of landscape video for end-screen elements like subscribe buttons and video cards during the final 5 to 20 seconds. Plan your outro so those cards do not land on faces or text. Q: How big is the safe zone for captions on Shorts? A: On Shorts the channel handle, caption, and audio chip overlay the lower-left, occupying roughly the bottom 22 percent. Keep burned-in subtitles above that area or YouTube's own caption block will overlap them. Q: Does the safe zone differ between mobile and desktop? A: The overlay positions are broadly the same, but mobile shows controls more persistently and Shorts only exist in the vertical view. Designing to the marked safe zones keeps content clear on both. #### Tile Calculator URL: https://geratools.com/tile-calculator Free tile calculator that works out how many tiles you need to cover a floor or wall from the surface area, tile size and a waste allowance. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter the surface: Choose your units and type the length and width of the floor or wall you are tiling. 2. Set the tile size and waste: Enter the dimensions of one tile and a waste percentage for cuts and breakages. 3. Read the tile count: The calculator returns the number of whole tiles to buy, including the waste allowance. FAQ: Q: How is the tile count worked out? A: It divides the surface area by the area of one tile to get the base count, multiplies by your waste factor, then rounds up to whole tiles since you cannot buy a fraction of a tile. Q: How much waste should I allow? A: A 10% waste allowance is typical for straight layouts; use 15–20% for diagonal patterns, large tiles, or rooms with many cuts. The default is 10%. Q: Is my data uploaded anywhere? A: No. All calculations run entirely in your browser and nothing is sent to a server. Q: What units does the calculator use? A: In metric mode the surface is in metres and tile size in centimetres; in imperial mode the surface is in feet and tile size in inches. The tool converts tile dimensions to match the surface area automatically. Q: Does it account for grout lines? A: No. It uses the nominal tile size, so for very small tiles with wide grout joints the count is a slight overestimate, which is usually safe given you also add a waste allowance. Q: Can I use it for walls as well as floors? A: Yes. The maths is identical — enter the wall's height and width as the surface dimensions instead of a floor's length and width. Q: Why does it round up? A: You can only buy whole tiles, so the result is rounded up to the next whole tile to guarantee full coverage including the waste margin. #### China Resident ID Decoder & Validator URL: https://geratools.com/china-resident-id-decoder Free China Resident Identity Card decoder and validator. Read the province, date of birth and gender from an 18-character ID and verify the ISO 7064 MOD 11-2 check character. Privacy-first — runs entirely in your browser, nothing is sent anywhere. How to use: 1. Enter the ID: Type or paste the 18-character Resident ID (the last character may be a digit or X). 2. Read the validity: The tool recomputes the ISO 7064 MOD 11-2 check character and tells you whether it matches the 18th character. 3. See the breakdown: It also decodes the province from the address code, the embedded date of birth, and the gender from the 17th digit. FAQ: Q: How does the check-character validation work? A: The 18-digit ID uses the ISO 7064 MOD 11-2 algorithm. The first 17 digits are multiplied by the weights 7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2, summed mod 11, and mapped to a check character (0-9 or X). The card is valid only if that matches the 18th character. Q: How accurate is the decoding? A: The province, date of birth (YYYYMMDD) and gender (17th-digit parity) follow the documented GB 11643 structure and are accurate, and the check character is verified exactly. The tool never confirms the ID belongs to a real, registered person. Q: What does each part of an 18-digit Chinese ID mean? A: Digits 1-6 are the address code (province, prefecture, county), digits 7-14 are the date of birth as YYYYMMDD, digits 15-17 are a sequence number whose 17th digit encodes gender, and digit 18 is the check character. Q: How is gender encoded in the ID number? A: The 17th digit indicates gender by parity — an odd value means male and an even value means female. The decoder reads this automatically. Q: Why can the check character be the letter X? A: The ISO 7064 MOD 11-2 check value ranges from 0 to 10. When it equals 10 it is written as the Roman numeral X, since a single position cannot hold two digits. Q: Is my ID number sent anywhere? A: No. This tool is privacy-first — all processing happens locally in your browser and the number never leaves your device. #### Steps to Distance Calculator URL: https://geratools.com/daily-step-distance Free steps-to-distance calculator. Convert your daily step count into kilometres and miles using a stride length estimated from your height (or your own measured stride), and get an estimate of calories burned. Privacy-first and runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your steps: Type the number of steps you walked, for example your daily step count from a phone or fitness tracker. 2. Set your stride: Either estimate your stride from your height (and sex) or, for more accuracy, enter a stride length you have measured yourself. 3. Read the distance: See the distance in kilometres and miles, your stride length, steps per kilometre and an estimate of calories burned. FAQ: Q: How does the calculator turn steps into distance? A: Distance = steps × stride length. If you estimate the stride from height, the tool uses the standard walking-stride factors height × 0.415 for men and × 0.413 for women. Steps per kilometre is 1000 ÷ stride length in metres. For best accuracy, measure your own stride and enter it directly. Q: How far is 10,000 steps? A: It depends on your stride. For a 175 cm man, the estimated stride is 175 × 0.415 = 72.6 cm, so 10,000 steps is about 7.26 km (roughly 4.5 miles). A shorter person covers less and a taller person more, which is why this tool estimates from your own height rather than a fixed average. Q: How accurate is the result? A: The distance is as accurate as your stride length, so a measured stride beats the height estimate. The calorie figure is a rough ballpark (about weight in kg × 0.0005 per step) and varies with pace, terrain and individual efficiency — treat it as an estimate, not a precise measurement. Q: How do I measure my own stride length? A: Mark a known distance such as 10 metres, walk it at a natural pace and count your steps, then divide the distance by the step count. For example, 10 m in 13 steps gives a stride of about 77 cm. Enter that in the manual stride option for the most accurate distance. Q: Is running stride the same as walking stride? A: No. Running strides are longer than walking strides, so this walk-focused estimate will under-count distance if you ran. If your steps came from running, measure your running stride and use the manual option instead of the height estimate. Q: Why does sex change the stride factor? A: On average, leg-length-to-height proportions differ slightly between men and women, so the walking-stride literature uses height × 0.415 for men and × 0.413 for women. The difference is small, and a measured stride overrides this estimate entirely. Q: Is my data kept private? A: Yes. Your step count, height and weight are processed entirely in your browser. Nothing is stored, logged or transmitted anywhere. #### Modulo Calculator (Remainder) URL: https://geratools.com/modulo-calculator Free modulo calculator. Compute the remainder a mod n in both the truncated convention (JavaScript, C, Java) and the floored convention (Python), plus the integer quotient. Privacy-first and runs entirely in your browser — nothing is sent anywhere. How to use: 1. Enter the dividend: Type the number a that is being divided. 2. Enter the divisor: Type the modulus n you are dividing by (it cannot be zero). 3. Read both remainders: The tool shows the truncated remainder, the floored remainder and the integer quotient. FAQ: Q: Why are there two different modulo results? A: Languages disagree on the sign of the remainder. The truncated convention (JavaScript, C, Java) gives a remainder with the sign of the dividend a. The floored convention (Python's % and the mathematical "mod n") gives a remainder with the sign of the divisor n, always in the range 0 to |n|. They only differ when exactly one of the numbers is negative. Q: How accurate is the calculation? A: It uses standard arithmetic rounded to ten decimals for display and is exact for integer inputs, which is the usual case for modulo. Division by zero is reported as undefined. Q: What is 17 mod 5? A: 17 mod 5 = 2, because 17 = 3 × 5 + 2. Both the truncated and floored conventions agree here since both numbers are positive. Q: What is -17 mod 5? A: It depends on the convention. Truncated (JavaScript/C/Java) gives -2; floored (Python/maths) gives 3. They differ because exactly one number is negative. Q: What is the difference between modulo and remainder? A: They are the same operation, but "remainder" usually implies the truncated result whose sign follows the dividend, while "modulo n" in mathematics usually means the floored result in the range 0 to |n|. Q: Is my input sent anywhere? A: No. The calculator is privacy-first — both numbers stay in your browser and nothing is transmitted to any server. #### Power (Watts) Calculator URL: https://geratools.com/power-watts-calculator Free electrical power calculator — find watts from voltage and current, current and resistance, or voltage and resistance. Runs entirely in your browser, nothing uploaded. How to use: 1. Pick your known values: Choose whether you know voltage and current, current and resistance, or voltage and resistance. 2. Enter the numbers: Type the two known values into the fields. 3. Read the power: The power in watts is calculated instantly below. FAQ: Q: What are the power formulas? A: P = V × I (voltage times current), P = I² × R (current squared times resistance), and P = V² / R (voltage squared divided by resistance). All three give power in watts. Q: Which formula should I use? A: Use whichever two quantities you already know. The calculator offers all three combinations so you never have to convert first. Q: How do I find watts from volts and amps? A: Multiply them: P = V × I. A 12 V supply delivering 2 A gives 12 × 2 = 24 watts. Choose the volts-and-amps mode for this. Q: How do I calculate power from current and resistance? A: Use P = I² × R. A 2 A current through a 3 Ω resistor dissipates 2² × 3 = 12 watts of power, all turned into heat in the resistor. Q: How do I calculate power from voltage and resistance? A: Use P = V² ÷ R. A 12 V drop across a 4 Ω resistor gives 12² ÷ 4 = 144 ÷ 4 = 36 watts. Q: Why are there three formulas for the same thing? A: They are all the same law combined with Ohm's law (V = I × R). Substituting V or I lets you compute power from whichever pair of quantities you happen to know. Q: Is anything uploaded? A: No — every calculation runs locally in your browser, with no network requests. #### Quarter Calculator URL: https://geratools.com/quarter-calculator Find which calendar quarter (Q1–Q4) any date falls in, plus the quarter start, end, length, day-of-quarter and days remaining. Runs entirely in your browser — no dates are uploaded. How to use: 1. Enter a date: Pick any date to look up. 2. Read the quarter: The tool shows which quarter (Q1–Q4) the date belongs to. 3. Check the details: See the quarter start, end, total days, day-of-quarter, and days remaining. FAQ: Q: Which months are in each quarter? A: Q1 is January–March, Q2 is April–June, Q3 is July–September, and Q4 is October–December. Each quarter is exactly three calendar months. Q: How is the quarter worked out? A: The calculator takes the month number (0–11 internally), divides by 3 and rounds down, then adds 1. So January–March give Q1, April–June give Q2, and so on up to October–December for Q4. Q: How many days are in each quarter? A: Q1 has 90 days (91 in a leap year), Q2 has 91 days, and Q3 and Q4 each have 92 days. The tool counts the exact days for the year you enter, so leap years are handled automatically. Q: What does "day of quarter" mean? A: It is how many days into the quarter your date is, counting the first day of the quarter as day 1. For example, 1 April is day 1 of Q2 and 30 April is day 30. Q: Does this use a fiscal quarter? A: No — this uses standard calendar quarters that always start in January, April, July and October. For non-calendar fiscal periods, use the fiscal year calculator. Q: Why might the start and end dates look shifted by a day? A: They should not — dates are handled in UTC to avoid time-zone drift, so a quarter always starts on the 1st and ends on the last day of its third month. Q: Is anything uploaded? A: No — every calculation happens locally in your browser and the date you pick is never sent anywhere. #### Change Maker Calculator URL: https://geratools.com/change-maker-calculator Free change-making calculator. Enter the amount owed and amount paid to get the change due plus the smallest breakdown of notes and coins. Runs entirely in your browser. How to use: 1. Enter the amount owed: Type the total price or amount the customer owes. 2. Enter the amount paid: Type the cash the customer handed over. 3. Read the change: The calculator shows the change due and the fewest notes and coins to make it up. FAQ: Q: How does it choose notes and coins? A: It uses a greedy breakdown from the largest denomination down (100, 50, 20, 10, 5, 2, 1, then 0.50 to 0.01), which gives the fewest pieces for standard currency systems. Q: What if the customer underpaid? A: If the amount paid is less than the amount owed, the tool shows how much more is still needed instead of a change breakdown. Q: Why does it work in cents internally? A: To avoid floating-point rounding errors, the tool converts both amounts to whole minor units (cents or pence) before subtracting and breaking down the change, so the result is always exact. Q: Does the greedy method always give the fewest coins? A: For canonical currency systems with 1/2/5-style denominations, yes — taking the largest denomination first is provably optimal. It can be suboptimal only for unusual, non-canonical denomination sets. Q: Is anything sent to a server? A: No: all calculations happen locally in your browser. #### Time Tracker & Timesheet URL: https://geratools.com/time-tracker Free browser-based time tracker and timesheet. Start/stop a live timer per project, log manual entries, see daily and weekly totals with a 7-day chart, set hourly rates for billable totals, and export a CSV timesheet. Everything stays in your browser — nothing is uploaded. How to use: 1. Add your projects: Open Manage projects, name each project, pick a colour and optionally set an hourly rate so billable totals calculate automatically. 2. Start a timer: Choose a project, type an optional note about what you are working on, and press Start. A live clock counts up while you work. 3. Stop or log manually: Press Stop when you finish, or use the Manual button to add a past block of time and edit its start and end directly. 4. Review daily and weekly totals: Switch between Today, This week and All time to see grouped entries, per-project breakdowns and a 7-day bar chart. 5. Export your timesheet: Click Export CSV to download a spreadsheet-ready timesheet, or Backup JSON to save everything for another device. FAQ: Q: How does the live timer work? A: When you press Start the tool records the exact start time and shows a clock that counts up every second. Pressing Stop records the end time and saves the entry. Only one timer runs at a time — starting a new one automatically stops the previous one so your hours never double-count. Q: Can I track billable hours and money? A: Yes. Give any project an hourly rate in the Manage projects panel and the tool multiplies your tracked hours by that rate. The billable total for the selected range appears in the summary and in the exported CSV, so you can paste the figures straight into an invoice. Q: What does the CSV export contain? A: One row per time entry with the date, project, note, start and end timestamps, duration in decimal hours, the hourly rate and the billable amount. It opens cleanly in Excel, Google Sheets or Numbers and respects the range you have selected (Today, This week or All time). Q: How are daily and weekly totals calculated? A: Each entry is bucketed by the local calendar day it started on. Daily totals sum every entry for that day; the weekly view sums the current Monday-to-Sunday ISO week. The 7-day bar chart shows the last seven days at a glance with today highlighted in green. Q: Is my data private and where is it stored? A: Everything is stored in your browser using localStorage and never leaves your device — there is no account, no server and no network request. Clearing your browser data or using private mode will remove it, so use Backup JSON to keep a copy or move data between machines. Q: Can I fix a forgotten timer or edit past entries? A: Yes. Every stopped entry has an edit button that lets you change the project, note, start time and end time using date-and-time pickers. You can also add a Manual entry for work you forgot to track and adjust its times to match what actually happened. #### Road Trip Time Estimator URL: https://geratools.com/road-trip-time-estimator Free road trip time estimator. Enter distance and average speed to get driving time, plus automatic rest and fuel stops for a realistic total. Works in miles or kilometres. Runs entirely in your browser. How to use: 1. Choose your units: Pick kilometres or miles, then enter the total distance of the trip. 2. Set your average speed: Enter a realistic average speed in km/h or mph for the route. 3. Add stop rules: Set how often you stop and for how long, and read the total estimated time below. FAQ: Q: How is driving time calculated? A: Driving time equals distance divided by average speed. Use an average that accounts for slower sections, not just the motorway cruising speed. Q: How are rest stops counted? A: The tool adds a stop after each segment of the distance you set, but not at the destination. For example, a 600 km trip stopping every 200 km has two intermediate stops. Q: Is this exact? A: No — it is a planning estimate. Real journeys vary with traffic, weather, roadworks and terrain. All maths runs locally in your browser. Q: Why add an average speed lower than the speed limit? A: Your average over a whole trip is always below the top cruising speed because of junctions, towns, slow traffic, and acceleration. A motorway trip might cruise at 70 mph but average 55–60 mph, so use a realistic average for a believable estimate. Q: How many stops will a long trip have? A: The number of intermediate stops is the distance divided by your stop interval, rounded down, since no stop is added at the destination. A 600 km trip stopping every 200 km has 2 stops; every 150 km gives 3. Q: Does it count stop time toward the total? A: Yes. The total time is driving time plus the duration of all intermediate stops, so it reflects the full day rather than just time behind the wheel. Q: Can I plan multi-day drives with it? A: You can use it for the day's driving total, then split your route into daily legs. It estimates one continuous trip; for overnight stops, run each day separately. #### Bill Reminder Tracker URL: https://geratools.com/bill-reminder-tracker Free bill reminder tracker. Log your rent, utilities, insurance and subscriptions with amounts, due dates and frequency, then see upcoming bills, your monthly total and overdue alerts. Export to calendar or CSV. Runs entirely in your browser. How to use: 1. Add each bill: Enter the bill name, amount, next due date, how often it repeats and a category. 2. Review what is coming up: The list sorts by soonest due and colour-codes overdue, due-today and due-soon bills. 3. Mark bills paid: Tapping Paid rolls a recurring bill forward to its next due date automatically. 4. Export to your calendar: Download an .ics file with reminders so the bills show up in any calendar app. FAQ: Q: How does the monthly total work? A: Each recurring bill is normalised to a comparable monthly figure. A yearly bill is divided by twelve, a quarterly bill by three, a fortnightly bill multiplied out across the year and so on. Adding those normalised amounts gives a fair monthly average even when your bills run on different cycles. One-off bills are excluded from this average because they do not repeat. Q: What happens when I mark a bill as paid? A: Recurring bills advance to their next due date based on the frequency you set, so a monthly bill jumps forward one month and a yearly bill jumps forward a year. One-off bills are cleared from the list once paid. Nothing is sent anywhere — the change is saved in your browser. Q: Will it remind me automatically? A: The tracker itself shows colour-coded due-soon and overdue badges whenever you open it. For push reminders, use the Export calendar button to download an .ics file; importing it into Google Calendar, Apple Calendar or Outlook adds a one-day-before alarm and repeats it on the same schedule. Q: Is my financial data private? A: Yes. Every bill, amount and due date stays in your browser's local storage. Nothing is uploaded, no account is required, and the page makes no network calls. Clearing your browser data or using private mode will remove the saved bills. Q: Can I track bills in different currencies? A: You pick one display currency for the whole tracker from the dropdown, including GBP, USD, EUR, AUD, CAD, INR, NGN and ZAR. Amounts are formatted with the correct symbol and grouping for that currency, but the tool does not convert between currencies. Q: What does the snooze button do? A: The +3d button pushes a single bill's due date three days later without changing its frequency. It is handy when you have arranged a short extension or simply want to be reminded again closer to the day. #### Timesheet Maker URL: https://geratools.com/timesheet-maker Free weekly timesheet maker. Track daily hours per project and task, set billable rates, see automatic totals and earnings, then export to CSV. Runs entirely in your browser — nothing is uploaded. How to use: 1. Set your week and rate: Pick the week-starting date, choose your currency and add an hourly rate to each row you want billed. 2. Log hours per day: Type the hours worked into each weekday cell for every project and task. Row, daily and weekly totals update instantly. 3. Export your timesheet: Check the billable amount, then click Download CSV to save a clean file you can email or import into a spreadsheet or invoice. FAQ: Q: How does the timesheet calculate billable amounts? A: Each row total is the sum of its seven daily hour entries. If the row is marked billable, that total is multiplied by the hourly rate you set for that row. The week total adds up every billable row, so you instantly see what to invoice. Q: Can I track more than one project in a single week? A: Yes. Add a row per project-and-task combination — for example two rows for the same client (one Design, one Meetings) or rows for completely separate clients. The By project panel automatically groups and rolls up hours and earnings for each project name. Q: What is the difference between billable and non-billable hours? A: Billable hours are work you charge a client for; non-billable hours (internal meetings, admin, training) are still tracked for your records but excluded from the billable amount. Untick the Bill checkbox on a row to keep its hours in your totals without adding to what you charge. Q: Does my timesheet data get uploaded anywhere? A: No. Everything runs in your browser and is saved only to this device using localStorage. Nothing is sent to a server, so your client names, rates and hours stay private. Clearing your browser data will erase the saved timesheet. Q: What does the rounding option do? A: The Round to setting only affects the exported CSV. Choosing 6, 15 or 30 minutes rounds each days hours to the nearest increment on export — useful if your client bills in fixed time blocks. On-screen totals always show the exact hours you entered. Q: Can I reuse the timesheet for next week? A: Yes. Use the Prev and Next week buttons to move the week-starting date, or pick a date directly. Your project rows and rates stay in place — use Clear hours to blank just the daily cells while keeping the structure, ready for a fresh week. #### Density Calculator URL: https://geratools.com/density-calculator Free density calculator. Solve the formula ρ = m ÷ V for density, mass, or volume. Supports kg/m³, g/cm³, lb/ft³ and more. Shows step-by-step working, floatation check, and a material comparison chart. Runs entirely in your browser. How to use: 1. Choose what to solve for: Select density, mass, or volume from the drop-down. The tool rearranges ρ = m ÷ V so the two known quantities become the inputs. 2. Enter the known values with units: Type your two known quantities and pick the appropriate unit from the selector next to each field. The calculator converts everything to SI internally before computing. 3. Choose your output unit: Use the output-unit selector to display the result in whichever unit you need — kg/m³, g/cm³, lb/ft³, and others are all available. 4. Read the result and working: The answer appears instantly alongside a step-by-step breakdown showing every conversion and the final formula application. 5. Compare with real materials: The bar chart and reference table let you see where your result sits relative to balsa wood, water, aluminium, steel, gold, and many more. FAQ: Q: What is the density formula? A: Density is defined as mass divided by volume — ρ = m ÷ V. Rearranged, mass = ρ × V and volume = m ÷ ρ. In SI units density is measured in kg/m³, but g/cm³ is equally common for solids and liquids because pure water equals exactly 1 g/cm³. Q: How do I convert g/cm³ to kg/m³? A: Multiply by 1000. One gram per cubic centimetre is the same as one thousand kilograms per cubic metre. For example, steel at 7.85 g/cm³ equals 7850 kg/m³. The calculator handles this conversion automatically whichever unit pair you choose. Q: What is the density of water? A: Pure (distilled) water reaches its maximum density of 1000 kg/m³ (exactly 1 g/cm³) at 3.98 °C. At 20 °C it is about 998 kg/m³, and seawater averages around 1025 kg/m³ due to dissolved salts. The floatation check in this calculator uses 1000 kg/m³ as the reference. Q: How does the floatation (buoyancy) check work? A: An object floats when its average density is less than the density of the surrounding fluid. This calculator compares the computed density against 1000 kg/m³ (fresh water) and reports whether the object would float or sink. For seawater (1025 kg/m³) adjust your comparison manually — objects that barely sink in fresh water can float in the sea. Q: Why does the calculator convert everything to SI first? A: Working in SI base units (kg for mass, m³ for volume, kg/m³ for density) prevents unit-mismatch errors. Once all values share a common system the formula ρ = m ÷ V is applied once, and then the result is converted back into whichever display unit you selected. Doing the conversion at the start and the display at the end is the standard engineering approach. Q: Which unit systems are supported? A: Density — kg/m³, g/cm³, g/mL, kg/L, lb/ft³, lb/in³. Mass — kg, g, mg, metric tonne (t), pound (lb), ounce (oz). Volume — m³, cm³, mL, litre (L), ft³, in³, US gallon. Mix units freely; the calculator converts each input independently. #### Heat Index Calculator URL: https://geratools.com/heat-index-calculator Free heat index calculator. Enter air temperature and relative humidity to get the feels-like temperature (heat index) using the official NOAA Rothfusz regression, plus the NOAA risk category from Caution to Extreme Danger. Runs entirely in your browser. How to use: 1. Choose your temperature unit: Toggle between Celsius and Fahrenheit. The calculator automatically converts the existing temperature value when you switch. 2. Enter the air temperature: Type the actual air temperature (dry-bulb, measured in shade). For best results use a value at or above 27 °C / 80 °F where heat index is meaningful. 3. Enter the relative humidity: Type the relative humidity as a percentage (0–100). Weather apps, phone widgets, and home weather stations all report this directly. 4. Read the feels-like result: The heat index appears instantly alongside the NOAA risk category — from green (no elevated risk) through yellow, orange, red, to purple (Extreme Danger). 5. Review the working: Expand the Working section to see every step of the Steadman simple estimate and Rothfusz regression so you can verify or learn the maths. FAQ: Q: What is the heat index and how is it different from air temperature? A: The heat index (also called "apparent temperature" or "feels-like temperature") combines air temperature and relative humidity to describe how hot the air actually feels to the human body. At high humidity, sweat evaporates more slowly, reducing the body's ability to cool itself, so the perceived temperature is higher than the thermometer reading. At 35 °C (95 °F) with 70% humidity, the heat index is around 50 °C (122 °F) — far above the measured air temperature. Q: What formula does this calculator use? A: It uses the official NOAA/NWS two-step method. First the Steadman (1979) simple estimate is computed and averaged with the actual temperature. If the average is below 80 °F (27 °C) that value is used directly. At or above 80 °F the full Rothfusz regression (a nine-term polynomial in T and RH) is applied, with two optional NWS adjustments for very low humidity (RH below 13%) or very high humidity (RH above 85%) at specific temperature ranges. Q: When is the heat index valid? A: The Rothfusz regression is most accurate when the air temperature is at or above 80 °F (27 °C) and relative humidity is 40% or higher. At lower temperatures or very low humidity the calculated value may be lower than the actual temperature, in which case the ambient temperature itself is the more relevant figure. The calculator flags this by showing no elevated risk category. Q: What are the NOAA heat index risk categories? A: NOAA defines four categories. Caution (27–32 °C / 80–91 °F) — fatigue possible with prolonged activity. Extreme Caution (32–41 °C / 91–103 °F) — heat cramps and heat exhaustion possible. Danger (41–54 °C / 103–125 °F) — heat cramps and heat exhaustion likely, heat stroke possible. Extreme Danger (above 54 °C / 125 °F) — heat stroke highly likely. These thresholds are based on healthy adults at rest in the shade; direct sun, physical exertion, and individual health factors all increase actual risk. Q: Does direct sunlight affect the heat index? A: Yes. The standard heat index assumes the person is in the shade. Direct sunlight can add 8–15 °C (roughly 15–25 °F) to the perceived heat, pushing the effective heat index into a higher risk category than the calculator shows. Always account for sun exposure, especially during outdoor work or exercise. Q: What should I do if the heat index is in the Danger or Extreme Danger zone? A: Move to a cool, air-conditioned environment. Drink water regularly — do not wait until you feel thirsty. Avoid strenuous outdoor activity during the hottest part of the day (typically 11am–3pm). Wear lightweight, light-coloured clothing. Check on elderly neighbours, young children, and pets. Know the signs of heat exhaustion (heavy sweating, weakness, cold/pale/clammy skin, fast pulse, nausea) and heat stroke (high body temperature above 40 °C, hot/red/dry skin, rapid pulse, unconsciousness) — the latter is a medical emergency requiring immediate cooling and emergency services. #### Name Day Finder URL: https://geratools.com/name-day-finder Look up name days for hundreds of first names across Catholic, Orthodox, Nordic, and Hungarian traditions. See the date, a countdown to the next celebration, and every name honoured on that day. Runs entirely in your browser — no network requests. How to use: 1. Switch to the right tab: Use "Look up by name" to search for a first name, or "Look up by date" to see which names are celebrated on a particular day of the year. 2. Type a first name: Enter any first name in the search box. The tool matches exact names and common prefix variants across all four calendar traditions simultaneously. 3. Check the countdown: Each result shows how many days remain until the next occurrence of that name day — useful for buying a card or planning a celebration in time. 4. Browse by date: Pick a month and day to see every name honoured on that calendar date, displayed as clickable chips you can copy in one click. FAQ: Q: What is a name day? A: A name day (also called a feast day or saints' day) is a tradition in many European and Latin American cultures of celebrating the calendar date associated with a person's first name. In countries such as Hungary, Poland, Sweden, Greece, and much of Catholic Europe, name days are marked as enthusiastically as birthdays — sometimes more so. The practice originated with the Catholic calendar of saints, where each day of the year is dedicated to one or more saints, and people named after that saint celebrate on that date. Q: Which calendar traditions does this tool cover? A: The tool draws on four overlapping traditions. The Catholic calendar assigns saints' feast days to most days of the year and underpins name-day customs across Poland, Hungary, Italy, Spain, Portugal, France, and Latin America. The Orthodox calendar shares many saints but often places them on different dates, and is widely observed in Greece, Russia, Serbia, Romania, and Armenia. The Nordic calendar (used in Sweden, Norway, Denmark, and Finland) formalised name days in the sixteenth century; Sweden still publishes an official list through its National Day of Sweden. The Hungarian calendar is particularly rich — Hungary treats name days as a national cultural institution with its own authoritative list. All four traditions are merged here so a single search covers all variants. Q: What if my name appears on more than one date? A: Many names appear in multiple traditions on different dates. For example, "Anthony" is celebrated on January 17 in the Catholic/Nordic tradition and on June 13 (the Feast of Anthony of Padua) in other Catholic regions. The tool returns every match and labels each result with its tradition, so you can pick the one that matches your cultural background or simply celebrate both. Q: My name is not in the list — why? A: The database covers several hundred of the most common names across these four traditions, but it cannot be exhaustive. Modern invented names, very regional names, names unique to a single country's calendar, and names added to official lists in recent decades may be absent. As a fallback, look up the patron saint most associated with your name's etymology — many national name-day organisations publish full searchable lists online. Q: Are name days the same every year? A: Yes. Unlike Easter-dependent moveable feasts, name days are tied to fixed calendar dates (month and day), so the date never shifts. The only exception is February 29, which only occurs in leap years; some traditions use February 28 or March 1 as a substitute in common years. Q: How is the countdown calculated? A: The tool reads today's local date from your device, constructs the next calendar occurrence of the name day (this year if it has not yet passed, next year if it has), and computes the difference in whole days. The result is recalculated each time you change the name or date — no server or network call is involved at any point. #### What Time Is It In…? URL: https://geratools.com/what-time-is-it-in Find out the current local time in any city or country worldwide. Live ticking clock, UTC offset, day/night indicator, and your time-difference at a glance — no API, no network calls. How to use: 1. Type a city or country name: Start typing in the search box — results appear instantly as you type. You can search by city name, country name, or IANA time-zone identifier. 2. Select your location from the dropdown: Click or tap the city you want. The live clock starts immediately, showing the current time, date, UTC offset, and whether it is daytime or night-time there. 3. Compare with your local time: Below the main clock you will see your own current time and the exact hour-and-minute difference between your location and the selected city. 4. Copy the result: Use the 'Copy to clipboard' button to share a formatted sentence with the full date, time, city, and UTC offset. FAQ: Q: How does this tool know the correct time without an internet connection? A: It uses the IANA time-zone database that is already built into every modern browser and operating system. The Intl.DateTimeFormat API reads your device clock (which is already synchronised via NTP) and applies the correct UTC offset and daylight-saving rule for the chosen location. No network request is made. Q: Does it handle daylight saving time automatically? A: Yes. The browser's Intl engine applies the DST rule for every zone at the exact moment you look up the time. If a city is currently observing summer time, you will see the summer offset — for example London shows UTC+1 in summer and UTC+0 in winter, Tokyo always shows UTC+9 because Japan does not observe DST. Q: What about half-hour and quarter-hour offsets? A: These are fully supported. India (UTC+5:30), Iran (UTC+3:30), Afghanistan (UTC+4:30), Nepal (UTC+5:45), and the Chatham Islands (UTC+12:45 in winter / UTC+13:45 in summer) all display the correct fractional offset because the calculation reads the raw zone offset from Intl rather than rounding to the nearest hour. Q: Why does the daytime indicator say night even though it seems bright outside? A: The day/night boundary used here is a simple threshold — 06:00 to 20:00 local time is classed as daytime. It does not account for latitude or season. At high latitudes (Reykjavik in summer, for instance) it may still be light well past 20:00. For precise sunrise and sunset times, use a dedicated astronomical calculator. Q: My city is not in the list — what should I do? A: Search by country name or a nearby major city that shares the same time zone. For example, most of England and Wales share Europe/London; most of eastern Australia shares Australia/Sydney or Australia/Melbourne. All cities within the same IANA zone always show identical times. Q: Is the time accurate to the second? A: The clock updates every second using your device's system time. Most devices synchronise with an NTP server automatically and stay within a fraction of a second of true UTC. The displayed seconds are therefore accurate to within roughly one second of real world time. #### Chinese Zodiac Calculator URL: https://geratools.com/chinese-zodiac-calculator Free Chinese Zodiac calculator. Enter your date of birth to discover your animal sign, Five-Element nature, Yin or Yang polarity, compatible signs, lucky numbers, lucky colours, and the next recurrence of your sign year. Uses the lunisolar Chinese New Year boundary for accuracy. Runs entirely in your browser. How to use: 1. Enter your date of birth: Type or pick your full birth date (day, month, year) in the date field. 2. Read your animal and element: The calculator shows your zodiac animal, its Chinese name, the Five-Element nature and Yin or Yang polarity. 3. Check compatibility and lucky attributes: Scroll down to see compatible animals, lucky numbers, lucky colours, a personality description, and famous people who share your sign. 4. Note the next recurrence year: The calculator tells you the next year your animal sign repeats — useful for planning auspicious timing. FAQ: Q: Why might people born in January or February have a different animal to their Gregorian birth year? A: Chinese New Year falls somewhere between 21 January and 20 February each year. If you were born before that date in a given year, the Chinese zodiac year had not yet turned, so your animal belongs to the previous year. This calculator uses an exact lookup table of New Year dates from 1900 to 2040 to handle this correctly. Q: What is the sexagenary (60-year) cycle? A: The Chinese calendar combines a 12-year animal cycle (Earthly Branches) with a 10-year cycle of Heavenly Stems (five elements each in Yin and Yang form). Because 12 and 10 share a lowest common multiple of 60, it takes 60 years before an identical animal-plus-element-plus-polarity combination repeats. The romanised pillar shown (e.g. Jiǎ-Zǐ) is your birth year's name in that system. Q: What are the Five Elements in Chinese astrology? A: The Five Elements (五行, Wu Xing) are Wood, Fire, Earth, Metal and Water. Each element governs two consecutive years — one Yang year followed by one Yin year. Your element influences personality, career aptitude, and health tendencies alongside the animal sign. For example, a Wood Rat (1984) differs meaningfully from a Water Rat (1972) in classical Chinese astrology. Q: What does Yin or Yang mean for a zodiac year? A: Every Heavenly Stem is either Yang (odd-numbered in the sequence) or Yin (even-numbered). Yang years are considered more outward, active and expansive; Yin years are regarded as more inward, receptive and consolidating. Whether the year itself is considered auspicious for you depends on your own birth sign and the interaction with the current year's energies. Q: What is the clash sign? A: In Chinese astrology each animal has one direct opposite on the zodiac wheel called its "clash" sign (冲, chong). When the current year matches your clash sign — for example a Rat in a Horse year — tradition holds that you may face more turbulence and advises carrying protective talismans or visiting a temple. It is a prompt for extra mindfulness rather than a prediction. Q: How accurate is the compatibility shown? A: The compatible-sign groupings are the classical "San He" (three-harmony) triads used in traditional Chinese astrology. They represent harmonious energy combinations that practitioners believe lead to mutual support and understanding. They are a useful framework for reflection, not a scientifically validated prediction system. #### Country Driving Side Lookup URL: https://geratools.com/country-driving-side-lookup Free country driving side lookup: find out if a country drives on the left or right. Covers 195 countries with historical switch notes. 100% offline, no API. How to use: 1. Type a country name or ISO code: Start typing in the search box and the list filters in real time. You can search by full name (e.g. "Thailand") or by the two-letter ISO code (e.g. "TH"). 2. Filter by driving side: Click "Drive left" or "Drive right" to see only the countries that share that traffic rule. Useful for planning multi-country road trips. 3. Read the result card: When exactly one country matches, a highlighted card appears with a small road diagram showing which lane the car travels in, plus any historical note about a past switch. 4. Copy the results: Click "Copy results as text" to export the filtered list to your clipboard for use in a spreadsheet or document. FAQ: Q: How many countries drive on the left? A: Approximately 76 countries and territories drive on the left (left-hand traffic, LHT). They make up about 35% of all nations but account for roughly a third of the world's road network by length, partly because large countries such as Australia, India, and the United Kingdom are LHT. Q: Why do some countries drive on the left? A: The left-hand rule traces back to horse-riding conventions where a right-handed rider drew their sword on the right and passed oncoming traffic on the left for safety. Britain codified this into law and exported it to much of its empire. Right-hand traffic became dominant in continental Europe partly through Napoleonic standardisation and was later adopted across the Americas. Q: Which countries switched driving side and when? A: Several countries have switched since the 20th century. Sweden made the most organised switch (called Dagen H) on 3 September 1967, moving from left to right overnight. Samoa switched from right to left in 2009 to align with its Pacific neighbours. Myanmar switched from left to right around 1970 under military decree. Q: Does the driving side affect which side the steering wheel is on? A: Usually yes. In left-hand traffic countries the steering wheel is on the right of the car (right-hand drive, RHD) so the driver sits closest to the road centre. In right-hand traffic countries the wheel is on the left (left-hand drive, LHD). However, cars are sometimes imported without conversion, so you can find RHD cars in some RHT countries and vice versa. Q: Is this data official? A: The data is compiled from official road traffic legislation and the Vienna Convention on Road Traffic records. A small number of territories (overseas islands, disputed regions) follow the rule of their administering country and are not listed separately. Q: Can I use this for planning a road trip across borders? A: Yes. The lookup is especially useful when planning overland crossings between countries with different traffic rules, such as crossing from Thailand (left) into Laos (right), or from the Republic of Ireland (left) into Northern Ireland which is also left, but then into mainland Great Britain which stays left throughout. Always verify locally before driving, as rules in free-trade zones or border crossings can have temporary exceptions. #### Mixed Number Calculator URL: https://geratools.com/mixed-number-calculator Free mixed number calculator. Add, subtract, multiply or divide any two mixed numbers and see the exact result as a simplified mixed number plus the step-by-step working. Runs entirely in your browser. How to use: 1. Enter the first mixed number: Type the whole part, then the numerator and denominator of the fractional part. Tick "Negative" if the number is below zero. 2. Choose your operation: Select add, subtract, multiply, or divide from the operation drop-down. 3. Enter the second mixed number: Fill in the whole, numerator and denominator for the second value. 4. Read the result: The answer appears instantly as a simplified mixed number and as a decimal. Click "Show working" to see every step. FAQ: Q: What is a mixed number? A: A mixed number combines a whole-number part and a proper fraction, for example 3 and 1/2. It is shorthand for the sum of the two parts (3 + 1/2 = 7/2 as an improper fraction). Q: How do you add mixed numbers? A: Convert each mixed number to an improper fraction, find the lowest common denominator (LCD), rewrite both fractions over that LCD, add the numerators, then simplify the result and convert back to a mixed number. The calculator shows every one of these steps. Q: How do you subtract mixed numbers? A: The process is the same as addition except you subtract the numerators after rewriting over the LCD. If the result is negative the calculator displays it with a leading minus sign. Q: How do you multiply mixed numbers? A: Convert both to improper fractions, multiply numerator by numerator and denominator by denominator, then simplify using the greatest common divisor (GCD). There is no need to find a common denominator for multiplication. Q: How do you divide mixed numbers? A: Convert the dividend to an improper fraction, flip the divisor (take its reciprocal), then multiply. For example 2 and 1/2 divided by 1 and 1/4 becomes (5/2) times (4/5) = 20/10 = 2. Q: How is the fraction simplified? A: The calculator divides both the numerator and denominator by their greatest common divisor (GCD), found with the Euclidean algorithm. The result is always in lowest terms. ## Developer Tools > Fast, private developer utilities — JSON, encoding, hashing, color, CSS, generators, formatters and reference cheatsheets. Everything runs client-side in your browser, so your code and data never leave your device. ### JSON & Data #### JSON Formatter & Validator URL: https://geratools.com/json-formatter Free JSON formatter and validator. Beautify, minify and check JSON for errors in your browser. Pinpoints syntax errors, copy with one click — no upload. How to use: 1. Paste your JSON: Drop your JSON into the input box. 2. Format or minify: Click Format to pretty-print and validate, or Minify to compact it. 3. Copy the result: Copy the formatted output with one click. FAQ: Q: Is my JSON sent to a server? A: No. Parsing, formatting and validation all happen in your browser using the built-in JSON.parse and JSON.stringify. Nothing is uploaded. Q: How do I know if my JSON is valid? A: If it's valid you'll see a green confirmation and the formatted output. If not, the exact parser error message is shown, usually with the character position so you can jump to the problem. Q: Can it handle large JSON? A: Yes, within your browser's memory. Because it runs locally there are no upload-size limits, though very large files (tens of MB) may render slowly. Q: What is the difference between formatting and minifying JSON? A: Formatting (pretty-printing) adds line breaks and indentation so the structure is readable. Minifying strips all whitespace down to a single line to make the payload as small as possible — useful for API responses and config embedded in code. Q: Why does my JSON fail with "Unexpected token"? A: The most common causes are a trailing comma after the last item, single quotes instead of double quotes around keys/strings, unquoted keys, or a missing closing bracket. JSON requires double quotes and forbids trailing commas and comments. Q: Does this validate JSON or just format it? A: Both. The tool runs JSON.parse first, so any output you see has been fully parsed and is guaranteed valid JSON. If parsing fails you get the error instead of output. Q: Can I change the indentation width? A: Yes. You can set the indent to 2 spaces (the common default), 4 spaces, or other widths before pretty-printing. #### SQL Playground URL: https://geratools.com/sql-playground A free online SQL playground that runs a full SQLite database entirely in your browser via WebAssembly. Load sample data, write JOINs, GROUP BY and CTEs, see the result table instantly and export to CSV. 100% private — nothing is uploaded. How to use: 1. Pick a sample dataset: Choose the HR/Employees or E-commerce dataset to get tables and rows preloaded, or start from a blank database. 2. Write your SQL: Edit the query in the editor — SELECT, JOIN, GROUP BY, subqueries, CTEs and even CREATE/INSERT all work. 3. Run and read the table: Press Run (or Ctrl/Cmd+Enter) to execute against the in-memory SQLite engine and see the result table. 4. Export the result: Click Export CSV on any result set to download the rows. Use Reset data to restore the seed tables. FAQ: Q: Is my data sent to a server? A: No. The entire SQLite database runs inside your browser using a WebAssembly build of SQLite. Your queries, tables and results never leave your device — only the engine's own WASM file is downloaded once on first load. Q: What SQL features are supported? A: Everything SQLite supports: SELECT with JOIN, GROUP BY, HAVING, ORDER BY, subqueries, common table expressions (WITH), window functions, CASE expressions, and DDL/DML like CREATE TABLE, INSERT, UPDATE and DELETE. It is real SQLite, not a limited subset. Q: Does the playground save my work? A: Yes. Your query text and the selected sample dataset are stored in your browser's localStorage, so when you come back the editor reopens exactly where you left off. The data itself is in-memory and rebuilds from the seed each session — use Reset data to start fresh. Q: Can I create my own tables? A: Absolutely. Pick the Blank dataset (or just run CREATE TABLE in any dataset) and define your own schema, insert rows, then query them. The whole database is yours to shape. Q: Why did my query return "no rows" instead of a table? A: Statements like CREATE TABLE, INSERT, UPDATE and DELETE do not return rows — the tool reports how many rows were affected instead. Only SELECT (and other row-producing statements) render a result table. Q: How is this different from an online SQL course tool? A: There is no sign-up, no sandbox limit and no fixed lesson. It is a free-form scratchpad: load realistic data, prototype a query, test an edge case, or check syntax — then export the result as CSV. It is ideal for practising SQL, debugging a query before pasting it into production, or teaching JOINs. #### CSV Explorer & Cleaner URL: https://geratools.com/csv-explorer Free online CSV explorer and cleaner. Paste or upload a CSV, sort and filter columns, trim whitespace, remove duplicate and empty rows, then export a clean CSV — all in your browser, nothing uploaded. How to use: 1. Add your CSV: Paste CSV text into the box or click Upload CSV file to load a .csv from your computer. The first row is treated as the header. 2. Choose cleaning options: Toggle Trim whitespace, Remove empty rows and Remove duplicate rows. The table and the row counter update live as you change options. 3. Sort and filter: Click any column header to sort (click again to reverse, a third time to clear), and type in the Filter box to keep only rows that match across any column. 4. Export the result: Click Download cleaned CSV to save the cleaned data, or Copy CSV to put it on your clipboard. FAQ: Q: Is my CSV data uploaded anywhere? A: No. Parsing, cleaning, sorting, filtering and export all run entirely in your browser using JavaScript. Your file never touches a server, which makes it safe for confidential exports, customer lists and financial data. Q: How does it decide which rows are duplicates? A: A row is a duplicate when every one of its cells exactly matches an earlier row. If Trim whitespace is on, cells are trimmed first, so "London" and " London " are treated as the same value and the second copy is removed. Q: What counts as an empty row? A: A row is empty when every cell is blank after trimming. Rows that are entirely commas (for example ",,,") are removed when Remove empty rows is enabled, but a row with even one value is always kept. Q: Does sorting understand numbers? A: Yes. When a whole column contains numeric values the sort is numeric, so 9 comes before 124 rather than sorting them as text. Mixed text and numbers fall back to a natural, case-insensitive comparison. Q: Does it handle quoted fields and commas inside values? A: It does. The parser follows the RFC 4180 standard, so quoted fields, commas and line breaks inside quotes, and escaped double-quotes are all read correctly. The exported CSV re-quotes any value that needs it. Q: Will my data still be here when I come back? A: Yes. Your pasted CSV and your cleaning options are saved in your browser's localStorage, so the tool restores them the next time you open the page on the same device. Click Clear to wipe the box. #### Apache Avro Schema Types URL: https://geratools.com/avro-schema-types Searchable Apache Avro type reference covering the eight primitives, complex types (record, enum, array, map, union, fixed) and logical types like decimal, date and timestamp-millis with JSON schema syntax. How to use: 1. Filter by kind: Switch between primitive, complex and logical types to narrow the list to what you need. 2. Search a type: Type a name such as "record", "union" or "timestamp" to jump to that Avro type. 3. Copy the JSON shape: Each entry shows the JSON schema representation you can paste directly into an .avsc file. FAQ: Q: What are the primitive types in Avro? A: Avro defines eight primitives: null, boolean, int (32-bit), long (64-bit), float, double, bytes and string. int and long are variable-length zig-zag encoded, and bytes/string are length-prefixed. Q: How do you make a field nullable in Avro? A: You use a union with null, like ["null", "string"]. By convention null is listed first when the default is null. The union order also determines which branch the default value applies to. Q: What is an Avro logical type? A: A logical type annotates a primitive or complex type with extra meaning, such as decimal on bytes/fixed, date on int, or timestamp-millis on long. Readers that do not understand the logical type fall back to the underlying base type. Q: What is the difference between an Avro enum and a union? A: An enum is a single type whose value is one of a fixed set of named symbols. A union lets a field hold a value of any one of several different types, including null. They solve different problems. Q: How is an Avro decimal stored? A: A decimal is a logical type backed by bytes or fixed, with precision and scale attributes. The bytes contain the unscaled two's-complement integer value; the scale attribute says where the decimal point goes. #### Avro Schema Viewer URL: https://geratools.com/avro-schema-viewer Free Apache Avro schema viewer. Parses Avro schema JSON (record, enum, array, union, map, fixed), validates structural rules, and renders a collapsible tree. Ideal for Kafka and Confluent Schema Registry work — fully client-side, nothing uploaded. How to use: 1. Paste your Avro schema: Drop an Avro schema JSON document — a record, enum, or any complex type — into the text area. A sample User record is preloaded. 2. Read the tree: Each field is expanded into a node showing its name, type, and key attributes such as enum symbols, array items, or union branches. 3. Check validity: Structural issues — a record missing fields, an enum with no symbols, a fixed type with no size — are listed with the path to the offending node. FAQ: Q: What Avro types does this support? A: It handles all primitive types (null, boolean, int, long, float, double, bytes, string) and the complex types record, enum, array, map, union, and fixed. Logical types attached to primitives are shown as a detail. Q: How are unions displayed? A: A union is written in Avro as a JSON array of types, for example ["null", "string"]. The viewer renders it as a union node with one child per branch, which is the standard way to express an optional or nullable field. Q: What structural rules are checked? A: A record must have a name and a fields array, each field needs a name and a type, an enum needs a non-empty symbols list, and a fixed type needs a numeric size. Array and map nodes must declare items and values respectively. Q: Does it validate data against the schema? A: No. This tool validates the structure of the schema document itself, not records encoded with it. It is meant for reviewing and auditing schema definitions before registering them in a schema registry. Q: Is my schema sent to a server? A: No. Parsing and validation run entirely in your browser in JavaScript. The schema never leaves your device, which is useful when working with internal Kafka topic definitions. #### Cargo.toml Builder (Rust) URL: https://geratools.com/cargo-toml-builder Build a Cargo.toml with package metadata, edition, a dependencies section of common crates (serde, tokio, reqwest, axum, clap), dev-dependencies and a release profile for a Rust lib or binary. How to use: 1. Set package details: Enter the crate name, version, edition and license, and choose whether it is a binary application or a library. 2. Pick crates: Tick the common dependencies you need — serde, tokio, reqwest, axum, clap, anyhow or tracing — and optionally include dev-dependencies. 3. Copy and build: Copy or download Cargo.toml, then run cargo build to resolve versions and generate Cargo.lock. FAQ: Q: How does Cargo interpret a version like "1.0"? A: By default a bare version string is a caret requirement, so 1.0 means at least 1.0.0 but below 2.0.0. Cargo picks the newest compatible release and records the exact choice in Cargo.lock. Use an explicit operator like =1.0.3 only when you need to freeze a single version. Q: What is the difference between dependencies and dev-dependencies? A: dependencies are compiled into your crate and ship to users. dev-dependencies are only used for tests, examples and benchmarks and are not built when someone depends on your crate, so test frameworks like criterion belong there to keep the public dependency tree small. Q: When should I pick lib versus bin? A: Choose bin for an application that produces an executable from src/main.rs. Choose lib for a reusable crate built from src/lib.rs that other crates depend on. A crate can also be both, but the tool emits the single target you select to keep the manifest simple. Q: What does the edition field control? A: The edition selects a stable set of language semantics, such as 2021 or 2024. Editions let Rust evolve syntax and idioms without breaking older code, since each crate opts into its own edition. New projects should use the latest edition the compiler supports. Q: Why enable LTO and codegen-units in the release profile? A: Link-time optimization (lto = true) and codegen-units = 1 let the compiler optimize across the whole program in one unit, producing faster, smaller release binaries at the cost of longer compile times. They only affect release builds, so debug builds stay fast. #### wrangler.toml Builder (Cloudflare Workers) URL: https://geratools.com/cloudflare-workers-wrangler-builder Create a valid wrangler.toml for Cloudflare Workers with worker name, main entry, account ID, compatibility date, routes, KV / R2 / D1 bindings, and an optional staging environment override — copy or download. How to use: 1. Name the worker: Set the worker name and main entry file (for example src/index.ts) that Wrangler will deploy. 2. Add bindings and routes: Optionally fill in a route pattern and KV, R2, or D1 binding details so your Worker can reach those resources. 3. Copy wrangler.toml: Copy or download the file into your project root and run wrangler deploy. FAQ: Q: What is the compatibility_date in wrangler.toml? A: The compatibility_date pins your Worker to a specific snapshot of the runtime's behaviour. Cloudflare uses it to apply or withhold breaking runtime changes, so setting a recent date keeps behaviour stable across deploys. Q: Do I need to include account_id? A: Not always. If you run wrangler login, the CLI resolves your account interactively. Setting account_id is useful in CI or when your token has access to multiple accounts and you need to disambiguate. Q: How do KV, R2, and D1 bindings work? A: Each binding maps a variable name your code uses (like MY_KV) to a real Cloudflare resource by its ID or name. At runtime the binding appears on the env object passed to your Worker, giving you typed access to storage and databases. Q: What does the [env.staging] block do? A: Named environments let one wrangler.toml describe multiple deploy targets. wrangler deploy --env staging uses the [env.staging] overrides — typically a different name and variables — while sharing the rest of the base config. Q: Where do I put wrangler.toml? A: Place wrangler.toml in the root of your Worker project next to package.json. The Wrangler CLI reads it automatically for deploy, dev, and tail commands. #### CSV Outlier Detector URL: https://geratools.com/csv-outlier-detector Free CSV outlier detector. Paste CSV data and flag anomalous values in each numeric column using the IQR fence method or Z-score thresholds, with adjustable sensitivity. Parsing and statistics run entirely in your browser — no upload. How to use: 1. Paste your CSV: Drop CSV text with a header row into the box; the tool detects which columns are numeric. 2. Choose a method and sensitivity: Pick IQR (with a multiplier, default 1.5) or Z-score (with a threshold, default 3) to control how aggressive the flagging is. 3. Review flagged cells: Outlier values are highlighted in the table and listed per column with the bounds that triggered them. FAQ: Q: How does the IQR method work? A: It sorts a column, finds the first and third quartiles (Q1 and Q3), and computes the inter-quartile range IQR = Q3 minus Q1. Any value below Q1 minus k times IQR or above Q3 plus k times IQR is an outlier; k defaults to 1.5 (the standard fence) and 3.0 marks extreme outliers. Q: How does the Z-score method work? A: It computes each column's mean and standard deviation, then the Z-score (value minus mean, divided by standard deviation) for every cell. Values whose absolute Z-score exceeds the threshold (commonly 3) are flagged as outliers. Q: Which method should I use? A: IQR is robust and works well on skewed data because quartiles are not pulled by extremes. Z-score assumes a roughly normal distribution and is sensitive to the very outliers you are hunting, so a few large outliers can mask others. Try both. Q: Is my data uploaded? A: No. The CSV is parsed and all statistics are computed in JavaScript in your browser. Nothing is sent to a server, so it is safe for confidential datasets. Q: What about empty cells or text in a numeric column? A: Non-numeric and empty cells are skipped when computing a column's statistics and are never flagged. A column is treated as numeric only if most of its non-empty cells parse as numbers. #### CSV to KML Converter URL: https://geratools.com/csv-to-kml Free CSV to KML converter — turn a spreadsheet with latitude and longitude columns into Google Earth Placemark KML in your browser. Optional name and description columns, instant download, nothing uploaded. How to use: 1. Paste your CSV: Include a header row with lat and lon columns (latitude/longitude also work), plus optional name and description columns. 2. Name the document: Set a document name that appears as the layer title inside Google Earth. 3. Copy or download: The KML updates instantly. Copy it or download a ready-to-open .kml file. FAQ: Q: What columns does the CSV need? A: It needs a latitude and a longitude column. The tool recognises headers named lat, latitude or y, and lon, lng, long, longitude or x. A name and description column are optional and become the Placemark title and balloon text. Q: What coordinate order does KML use? A: KML stores coordinates as longitude,latitude,altitude — the opposite order from most spreadsheets. This converter handles the swap for you, so you simply provide lat and lon columns and it writes them in the correct KML order. Q: What happens to rows with bad coordinates? A: Rows whose latitude or longitude are not numbers, or fall outside the valid range (lat -90 to 90, lon -180 to 180), are skipped. The tool reports how many valid placemarks were generated so you can spot missing data. Q: Is my data uploaded to Google or any server? A: No. Parsing and KML generation run entirely in your browser using JavaScript. Your spreadsheet never leaves your machine, which makes the tool safe for confidential location data. Q: Can I open the result in Google Earth? A: Yes. Download the .kml file and double-click it, or drag it into Google Earth Pro or the web version. The placemarks appear under the document name you chose. #### DNS-over-HTTPS Privacy Query Tester URL: https://geratools.com/dns-over-https-query-tester Perform an A/AAAA DNS lookup for any domain through the Cloudflare (1.1.1.1) and Google (8.8.8.8) DNS-over-HTTPS endpoints directly from your browser with fetch(). Compare the resolved IPs from both resolvers, inspect TTLs and the response status, and verify that encrypted DoH answers match — no API key required. How to use: 1. Enter a domain: Type a hostname such as example.com. Do not include a protocol or path — just the domain you want to resolve. 2. Pick the record type: Choose A (IPv4), AAAA (IPv6), or another supported type. The tool queries both Cloudflare and Google in parallel. 3. Compare the answers: Read the resolved addresses, TTLs, and response status from each resolver. Matching answers confirm consistent, encrypted DoH resolution. FAQ: Q: What is DNS-over-HTTPS (DoH)? A: DoH sends DNS queries inside an encrypted HTTPS request instead of plain UDP port 53. This stops on-path observers from seeing or tampering with which domains you look up, improving privacy on shared and untrusted networks. Q: Why query both Cloudflare and Google? A: Comparing two independent public resolvers lets you spot inconsistencies. If both return the same A record you can be confident the answer is authoritative; a mismatch can indicate caching, geo-DNS, or local interception. Q: Does this need an API key? A: No. Cloudflare (cloudflare-dns.com) and Google (dns.google) both expose free, keyless DoH JSON endpoints that accept cross-origin requests, so the lookup runs entirely from your browser with fetch(). Q: What does the Status code mean? A: It is the DNS RCODE. 0 (NOERROR) means success, 3 (NXDOMAIN) means the name does not exist, and 2 (SERVFAIL) means the resolver could not complete the query. The tool labels these for you. Q: Why do I sometimes get different IPs from each resolver? A: Large sites use geo-aware and load-balanced DNS, so different resolvers (or the same resolver at different times) can hand back different but equally valid IPs. A short TTL also means answers rotate frequently. #### Fake GeoJSON Generator URL: https://geratools.com/fake-geojson-generator Generate random GeoJSON Point, LineString, and Polygon features wrapped in a valid FeatureCollection, complete with fake property data. Ideal for testing Leaflet, Mapbox GL, and other mapping libraries with realistic spec-compliant data. How to use: 1. Choose a geometry type: Select Point, LineString, Polygon, or Mixed to control which geometry types appear in the output. 2. Set a center and count: Enter a center latitude and longitude so features cluster around your area of interest, plus how many features you want. 3. Generate and copy: Click Generate to build a valid FeatureCollection, then copy the JSON straight into your map or fixture file. FAQ: Q: Is the output valid GeoJSON? A: Yes. The tool emits a FeatureCollection following RFC 7946, with coordinates ordered as longitude then latitude, and polygon rings closed by repeating the first vertex at the end. It should load directly into Leaflet, Mapbox GL, or any spec-compliant viewer. Q: Why are coordinates longitude first? A: The GeoJSON specification requires position arrays in the order longitude, latitude, which is the opposite of the common human-readable lat, lon convention. Mixing these up is the most frequent GeoJSON bug, so the tool always uses the spec order. Q: What is in the properties of each feature? A: Every feature gets a small set of fake attributes — an id, a generated name, a category, a numeric value, and a boolean active flag — so you can test styling, popups, and filtering logic against realistic property keys. Q: How are polygons kept valid? A: Each polygon is built as a ring of vertices arranged around the center point, and the first vertex is repeated as the last so the ring is properly closed. This satisfies the GeoJSON requirement that linear rings form a closed loop. Q: Does this send my data anywhere? A: No. Generation runs entirely in your browser with no API calls, so you can produce as many features as you like privately and offline. #### GeoJSON Minifier URL: https://geratools.com/geojson-minifier Free GeoJSON minifier — removes all JSON whitespace and optionally rounds coordinates to a chosen decimal precision (5dp is roughly 1 metre) to cut file size for faster web maps. Runs entirely in your browser. How to use: 1. Paste your GeoJSON: Drop a FeatureCollection, Feature, or raw geometry into the input box. 2. Pick a precision: Choose how many decimal places to keep for each coordinate, or turn rounding off to only strip whitespace. 3. Copy the result: The minified output and its size saving appear instantly. Click Copy to grab it. FAQ: Q: How much accuracy do I lose by rounding coordinates? A: At the equator, 5 decimal places is about 1.1 metres, 6dp is about 0.11 metres, and 4dp is about 11 metres. Web maps rarely need more than 5dp, so trimming from the typical 15 stored digits is lossless for display purposes. Q: Does minifying change the geometry? A: Stripping whitespace never changes anything. Rounding shifts each coordinate by at most half a unit of the chosen precision, which is invisible on a normal map but can matter for survey-grade data, so keep an unrounded copy if exact values are required. Q: Does it validate the GeoJSON? A: It parses the input as JSON and rejects invalid syntax with an error message. It does not enforce the full GeoJSON spec, but it does walk every coordinate array so malformed geometry is usually surfaced. Q: Is my data uploaded anywhere? A: No. Parsing, rounding, and re-serialising all happen locally in your browser, so sensitive location data never leaves your machine. Q: Why is my file still large after minifying? A: Most of a GeoJSON file's size is the coordinate digits themselves, not whitespace. If you only strip whitespace the saving is modest; rounding to 5 or 6 decimals usually removes the bulk of the bytes. #### GeoJSON to GPX Converter URL: https://geratools.com/geojson-to-gpx Free GeoJSON to GPX converter that runs entirely in your browser. Maps Point, LineString, MultiLineString and Polygon geometries to GPX waypoints and tracks, reading RFC 7946 [lon, lat] order. No backend, no upload, no location-data exposure. How to use: 1. Paste or load GeoJSON: Paste a GeoJSON Feature or FeatureCollection, or open a .geojson file. It is parsed locally and never uploaded. 2. Convert: The tool reads each geometry, applies the lon,lat ordering, and builds standards-compliant GPX 1.1. 3. Copy or download: Copy the GPX or download a .gpx file to import into Garmin, Strava, Komoot or any GPS device. FAQ: Q: Which GeoJSON geometries are supported? A: Point becomes a GPX waypoint. LineString becomes a track with one segment. MultiLineString becomes a track with one segment per line. A Polygon's outer ring is exported as a track, since GPX has no polygon type. Q: How does coordinate order work? A: GeoJSON stores coordinates as [longitude, latitude, optional elevation]. GPX uses separate lat and lon attributes, so the converter reads index 0 as longitude and index 1 as latitude and writes them in the right GPX slots. Q: Are feature properties kept? A: A feature's properties.name is used as the waypoint or track name, and properties.desc or properties.description becomes the GPX desc. Other arbitrary properties are not part of the GPX schema and are not emitted. Q: What if I paste a single Feature instead of a FeatureCollection? A: Both work. The converter accepts a bare Feature, a FeatureCollection, or even a raw geometry object, normalising each into a list of features before building the GPX. Q: Is my GeoJSON uploaded anywhere? A: No. Parsing and conversion run entirely in your browser. Your geographic data never reaches a server, is never logged, and never leaves your device. #### GeoJSON to TopoJSON Converter URL: https://geratools.com/geojson-to-topojson Encode a GeoJSON FeatureCollection as a TopoJSON topology, extracting line segments into a shared arc array and applying delta-encoded quantization to cut redundancy. Shows the compression ratio and gives downloadable TopoJSON. Runs entirely in your browser. How to use: 1. Paste GeoJSON: Paste a GeoJSON Feature or FeatureCollection with Polygon, MultiPolygon, or LineString geometry. 2. Set quantization: Choose a quantization grid size — higher values keep more coordinate precision, lower values compress more. 3. Copy the TopoJSON: Review the size reduction, then copy or download the generated TopoJSON object. FAQ: Q: How does TopoJSON make files smaller? A: TopoJSON stores boundaries shared between two shapes — like a border between adjacent countries — as a single arc referenced by both. GeoJSON repeats those coordinates in every feature, so eliminating the duplication plus delta encoding can dramatically shrink the file. Q: What does quantization do? A: Quantization snaps every coordinate onto an integer grid of the chosen size, replacing floating-point longitudes and latitudes with small integers. Combined with delta encoding, where each point stores only its offset from the previous one, this produces short repetitive numbers that compress well. Q: Which geometry types are supported? A: Point, MultiPoint, LineString, MultiLineString, Polygon, and MultiPolygon are supported. Points are stored directly in the topology; line and polygon rings are converted into the shared arc array. Q: Will the output match the d3 topojson library? A: It follows the TopoJSON 1.0 specification — a topology object with arcs, transform, and named objects — so it round-trips through standard TopoJSON clients. Exact arc ordering may differ from topojson-server, but the decoded geometry is equivalent. Q: Is my data uploaded? A: No. The entire topology build, including arc extraction and quantization, happens in your browser. Nothing is sent to any server. #### GraphQL Schema Visualizer URL: https://geratools.com/graphql-schema-visualizer Free GraphQL schema visualizer. Parses a GraphQL SDL document, lists every type, interface, input, enum and union, and maps the relationships between types as graph edges. Runs entirely in your browser — no schema is transmitted. How to use: 1. Paste your SDL: Drop a GraphQL Schema Definition Language document into the text area. A sample blog schema with User, Post and Comment types is preloaded. 2. Read the type list: Every type, interface, input, enum, union and scalar is listed with its fields and return types. 3. Follow the relationships: The edge table shows each field that returns another defined type, which is the adjacency list of the schema's relationship graph. FAQ: Q: What is a GraphQL relationship edge? A: An edge is created whenever a field on one type returns another type defined in the schema. For example, a Post type with an author field of type User produces the edge Post.author to User. These edges form the directed graph of how your types connect. Q: Does it use the official graphql.js parser? A: It uses a focused SDL tokenizer that extracts type, interface, input, enum, union and scalar definitions along with their fields. This keeps the tool dependency-free and fast while covering the constructs needed to map relationships. Q: How are list and non-null types handled? A: A field type such as [Post!]! is shown in full, but for relationship mapping it is reduced to the bare named type Post. List wrappers and the non-null exclamation marks do not change which types are connected. Q: Why is a field flagged as referencing an unknown type? A: That happens when a field returns a name that is neither a built-in scalar (Int, Float, String, Boolean, ID) nor a type defined elsewhere in the pasted schema. It usually means a typo or a missing definition. Q: Is my schema uploaded anywhere? A: No. The schema is parsed locally in your browser using JavaScript. Nothing is sent to a server, so it is safe to inspect private or internal GraphQL schemas. #### JSON-LD Article Schema Builder URL: https://geratools.com/json-ld-article Build valid JSON-LD Article (or NewsArticle / BlogPosting) structured data with headline, author, datePublished, dateModified, publisher with logo, image, mainEntityOfPage, and description. Outputs a paste-ready script tag for rich results. How to use: 1. Enter the article details: Fill in the headline, author, publish and modified dates, image URL, and the page URL. 2. Add the publisher and logo: Provide the publisher name and a logo URL so search engines can attribute the article correctly. 3. Copy the script tag: Copy the generated JSON-LD script block and paste it inside the head or body of your article page. FAQ: Q: What is JSON-LD and why use it for articles? A: JSON-LD is a JSON-based format for embedding structured data, recommended by Google. An Article schema describes a page to search engines so it can qualify for rich results such as Top Stories and enhanced snippets, and helps engines understand the author, dates, and publisher. Q: What is the difference between Article, NewsArticle, and BlogPosting? A: They are increasingly specific subtypes. Article is the general type, NewsArticle is for journalistic news content, and BlogPosting is for blog posts. Pick the one that best matches your content; the required fields are the same and search engines treat them similarly. Q: Which fields are required? A: Google recommends at least headline, image, datePublished, and either author or publisher with a logo. This builder always emits headline, author, datePublished, dateModified, publisher with logo, and mainEntityOfPage so your markup is complete and eligible for enhanced results. Q: How should dates be formatted? A: Dates must be in ISO 8601 format, ideally with a timezone offset, for example 2026-06-06T09:00:00+00:00. The tool converts the dates you pick into ISO 8601 automatically so search engines parse them reliably. Q: Where do I put the script tag? A: Place the script block anywhere in the head or body of the matching article page. It must be on the same page as the content it describes, and the values, such as headline and dates, must match what users actually see. #### JSON-LD Event Schema Builder URL: https://geratools.com/json-ld-event Generate valid Event JSON-LD with name, start and end dates, online or physical location, organizer, performer and ticket offer details. Produces a script tag ready for Google event rich results. How to use: 1. Describe the event: Enter the event name, description, and start and end date-times. Use the date pickers to avoid time-zone formatting mistakes. 2. Set the location: Choose whether the event is in person, online, or mixed, then fill in the venue address or the streaming URL accordingly. 3. Copy the schema: Copy the script tag into your event page and validate it with Google's Rich Results Test before publishing. FAQ: Q: What is Event structured data for? A: It lets search engines understand event details like date, venue and tickets. Google can then surface your event in the dedicated events experience and in result snippets, driving more qualified visits. Q: How should dates be formatted? A: Schema.org expects ISO 8601 date-times, ideally with a time-zone offset such as 2026-09-01T19:00:00-04:00. This builder uses datetime-local inputs and emits ISO strings so the format is always correct. Q: What is eventAttendanceMode? A: It declares whether an event is offline, online, or both, using schema.org URL values. Online and mixed events should also include a VirtualLocation with the streaming URL so Google can label them correctly. Q: Do I need an offers block? A: It is optional but valuable. Adding price, currency, availability and a ticket URL lets search engines show ticket information and a buy link directly in the events module. Q: Can I mark an event as cancelled? A: Yes. The eventStatus field accepts values like EventCancelled, EventPostponed or EventRescheduled. Keeping this accurate prevents users from arriving at a cancelled event. #### JSON-LD JobPosting Schema Builder URL: https://geratools.com/json-ld-job-posting Build a valid JobPosting JSON-LD with title, description, employment type, salary range, job location, remote flag, hiring organization and validThrough date for eligibility in Google Jobs. How to use: 1. Enter the role: Add the job title, full description, employment type and the date the posting was published. 2. Set pay and location: Enter a salary range and unit, then add the work location or mark the role as fully remote. 3. Copy the schema: Copy the generated script tag onto your job page and validate it with Google's Rich Results Test. FAQ: Q: What is JobPosting structured data for? A: It makes a job listing eligible for the Google Jobs experience, where roles appear in a dedicated search widget with filters for salary, location and type. This dramatically increases qualified applicant reach for free. Q: Is datePosted required? A: Yes, Google requires datePosted in ISO 8601 date format, and validThrough is strongly recommended. Expired postings without a validThrough can linger in results, so always set an expiry. Q: How do I mark a job as remote? A: Set jobLocationType to TELECOMMUTE and add an applicantLocationRequirements country. This builder toggles those fields when you check the remote box, while still allowing an optional base location. Q: How is salary structured? A: Salary uses a MonetaryAmount with a nested QuantitativeValue holding minValue, maxValue, and a unitText such as HOUR, YEAR or MONTH. The tool builds this object so the format always validates. Q: Why does my job not appear in Google Jobs? A: Common causes are a missing validThrough, an expired posting, blocked crawling, or the page not being indexed. Valid markup is required but the page must also be crawlable and the job must be current. #### JSON-LD LocalBusiness Schema Builder URL: https://geratools.com/json-ld-local-business Build a complete LocalBusiness JSON-LD schema with name, postal address, phone, opening hours, geo coordinates, price range and accepted currencies. Copy the script tag straight into your contact or home page. How to use: 1. Enter business details: Add the business name, full address, phone number and website. These populate the core LocalBusiness and PostalAddress fields. 2. Set hours and location: Pick opening and closing times per day and optionally add latitude and longitude for a precise GeoCoordinates block. 3. Copy the markup: Copy the generated script tag into your site and verify it in Google's Rich Results Test before publishing. FAQ: Q: What does LocalBusiness schema do? A: It gives search engines the structured details of a physical business — address, hours, phone and location. This powers richer Google Maps and knowledge-panel listings and helps local-pack ranking signals. Q: Should I use a more specific business type? A: If one fits, yes. Schema.org has subtypes like Restaurant, Dentist or Plumber that inherit from LocalBusiness. This tool lets you set the @type so you can pick the most specific match. Q: How are opening hours formatted? A: Each day becomes an OpeningHoursSpecification entry with dayOfWeek plus opens and closes in 24-hour HH:MM format. Days marked closed are simply omitted from the array. Q: Do I need latitude and longitude? A: They are optional but recommended. Accurate GeoCoordinates help search engines place your pin precisely, which matters for map results in dense areas where the address alone is ambiguous. Q: What is priceRange? A: It is a free-text indicator of cost, commonly shown as one to four currency symbols such as $$ or a range like £10-£30. It is a hint for users, not a precise price. #### JSON-LD Person Schema Builder URL: https://geratools.com/json-ld-person Outputs a valid Person JSON-LD schema with name, jobTitle, affiliation, sameAs social links, email, and image for author bios, about pages, and knowledge panel eligibility. How to use: 1. Enter the person's identity: Add the full name, job title, and the organization they are affiliated with. 2. Add links and media: Provide an email, profile image URL, and one social or profile URL per line in the sameAs box. 3. Copy the JSON-LD: Copy the output and paste it into a script tag with type application/ld+json on the author or bio page. FAQ: Q: What is Person schema used for? A: Person structured data identifies an individual such as an author, founder, or public figure. It supports Google's E-E-A-T signals and can feed a knowledge panel for notable people. Q: Should every author page have this? A: Yes for content sites. Marking up the byline author with a Person schema clarifies who wrote a piece, which strengthens authorship and expertise signals. Q: What goes in the affiliation field? A: affiliation is the organization the person belongs to, modeled as a nested Organization object with a name. Use the employer, university, or company. Q: Does the email get exposed publicly? A: Yes — anything in JSON-LD is visible in page source. Only include an email you are comfortable publishing, or leave it blank to omit it. Q: How do I link this to my Organization schema? A: Reference the same organization name in both the Person affiliation and your Organization block so search engines connect the entities cleanly. Validate both with the Rich Results Test. #### JSON-LD Review Schema Builder URL: https://geratools.com/json-ld-review Generate a Review or AggregateRating JSON-LD block with author, review body, rating value, best and worst rating, and the item being reviewed. Outputs a ready-to-paste script tag for review rich results. How to use: 1. Choose the schema type: Pick a single Review for one testimonial or an AggregateRating for an overall score across many reviews. 2. Fill in the details: Enter the item being reviewed, the rating value, and for a single review, the author and review body. 3. Copy the markup: Copy the script tag onto the page that displays the review and verify it with Google's Rich Results Test. FAQ: Q: What is the difference between Review and AggregateRating? A: A Review marks up one person's opinion with an author and body, while an AggregateRating summarises many reviews into one score and count. Use Review for a single testimonial and AggregateRating for an overall star average. Q: Can review snippets show on their own? A: Google requires review markup to be nested on the thing reviewed, such as a Product, LocalBusiness or Recipe. This tool wraps the rating inside an itemReviewed object so the markup is self-contained and valid. Q: What rating scale should I use? A: The default scale is 1 to 5, set by bestRating and worstRating. You can use another scale, like 1 to 10, as long as ratingValue stays within the bounds you declare. Keep the scale consistent across your site. Q: Does Google allow self-serving reviews? A: No. Google forbids marking up reviews you wrote about your own business or that you collected on a third-party site. Only mark up genuine, independent reviews shown on your own page. Q: Why are my review stars not showing? A: Common reasons are the reviewed item type being ineligible, the rating not being visible on the page, or the markup not matching the on-page content. Valid markup plus visible, matching content is required. #### JSONC / JSON5 Syntax Reference URL: https://geratools.com/jsonc-syntax-reference Reference comparing JSONC and JSON5 syntax extensions against strict JSON, including comments, trailing commas, unquoted keys, single quotes, hex numbers and special float values. How to use: 1. Compare the dialects: Each row shows whether a feature is allowed in JSON, JSONC and JSON5. 2. Filter by dialect: Switch to JSONC supports or JSON5 supports to see only the features that dialect adds. 3. Search a feature: Type a term like comment, trailing comma or hex to jump to its support row. FAQ: Q: What is the difference between JSONC and JSON5? A: JSONC (JSON with Comments) is a small superset that adds only line and block comments plus trailing commas; it is what VS Code uses for tsconfig.json and settings. JSON5 is a much broader superset that also allows unquoted keys, single-quoted strings, hexadecimal numbers, leading or trailing decimal points, and special values like Infinity and NaN. Q: Can I parse JSONC or JSON5 with JSON.parse? A: No. The standard JSON.parse function rejects comments, trailing commas and every other extension. You must either strip the extensions first or use a dedicated parser such as the json5 package or jsonc-parser. Q: Are comments allowed in JSON? A: Not in standard JSON, which has no comment syntax at all. JSONC and JSON5 both add C-style line comments with two slashes and block comments delimited by slash-star and star-slash. Q: Does JSON5 allow trailing commas? A: Yes. Both JSONC and JSON5 allow a comma after the final element of an array or the final member of an object, which makes diffs cleaner and reordering easier. Q: Are unquoted object keys valid anywhere? A: Only in JSON5. Standard JSON and JSONC both require keys to be double-quoted strings. JSON5 permits identifier-style keys without quotes, similar to JavaScript object literals. #### JSONPath Syntax Reference URL: https://geratools.com/jsonpath-syntax Interactive JSONPath syntax reference covering RFC 9535 segments — root, child, recursive descent, wildcards, array slices, filter expressions and function extensions — each with an example expression and what it selects. How to use: 1. Search the operators: Type a symbol or keyword such as "filter" or ".." to filter the JSONPath segment reference. 2. Read each example: Every entry shows the JSONPath syntax, an example expression and a plain-English description of what nodes it selects. 3. Build your path: Combine segments — root, child, recursive descent and filters — to target the exact nodes you need in a JSON document. FAQ: Q: What is RFC 9535? A: RFC 9535 is the 2024 IETF standard that finally specifies JSONPath formally, ending years of divergent implementations. It defines the root identifier $, child segments, the descendant segment .., wildcards, array slices, filter selectors and a small set of function extensions like length() and count(). Q: What is recursive descent in JSONPath? A: The descendant segment, written .., searches the current node and all of its descendants at any depth. For example $..price selects every price field anywhere in the document, no matter how deeply nested. It is powerful but can be slow on large documents. Q: How do filter expressions work? A: A filter selector ? keeps only the items for which the expression is true. Inside the filter, @ refers to the current item, so $.items[?@.price < 10] selects items whose price is under 10. Filters support comparison, &&, || and existence tests. Q: What is the difference between $ and @ in JSONPath? A: $ is the root of the whole document and starts every JSONPath query. @ is the current node being tested and is only valid inside a filter expression. Use $ to reach back to the document root from within a filter, and @ to reference the item under evaluation. Q: Does JSONPath array slicing match Python? A: Yes, RFC 9535 slices follow Python semantics: [start:end:step] is half-open, supports negative indices counting from the end, and a default step of 1. For example [1:3] selects indices 1 and 2, and [::-1] reverses the array. #### Mock YAML Generator URL: https://geratools.com/mock-yaml-generator Generate valid YAML documents with nested maps, lists, and correctly typed values (strings, numbers, booleans, nulls). Test Kubernetes manifests, CI config parsers, and infrastructure tooling with realistic sample config. How to use: 1. Pick a preset: Choose a generic config, a Kubernetes-style manifest, or a CI pipeline shape to match the parser you are testing. 2. Set list sizes: Choose how many list items to emit so you can test short samples or larger nested structures. 3. Generate and copy: Click Generate to produce indented, valid YAML and copy it to your clipboard for use in fixtures or demos. FAQ: Q: Is the output valid YAML? A: Yes. The generator uses two-space indentation, the standard YAML convention, with no tabs (which YAML forbids). Keys map to values via colon-space, lists use hyphen-space, and special string values are quoted so they parse as strings rather than booleans or numbers. Q: How are data types represented in YAML? A: YAML infers types from syntax: true and false are booleans, bare digits are numbers, null or ~ is null, and other bare words are strings. Strings that look like booleans or numbers are quoted to preserve them, which this tool does automatically. Q: Can I use this for Kubernetes manifests? A: The Kubernetes preset emits a manifest-shaped document with apiVersion, kind, metadata, and spec sections. It is structurally representative for testing parsers and templating, though you should validate against the real schema before applying it to a cluster. Q: Why two-space indentation? A: YAML uses indentation to express structure and explicitly disallows tab characters for indentation. Two spaces per level is the near-universal convention in Kubernetes, CI, and tooling configs, so the generator follows it for maximum compatibility. #### MySQL Data Types Reference URL: https://geratools.com/mysql-data-types Searchable MySQL and MariaDB data type reference covering integer, fixed and floating point, string, binary, date/time and JSON types — with storage size, value range and STRICT-mode notes. How to use: 1. Search a type: Type part of a type name or its range, such as "VARCHAR" or "TIMESTAMP", to filter the list. 2. Filter by category: Choose a category like integer, string or date/time to narrow the list. 3. Use it in DDL: Copy the type into a CREATE TABLE column definition, picking the narrowest type that fits the data. FAQ: Q: What is the difference between DATETIME and TIMESTAMP? A: DATETIME stores the literal value you give it, independent of time zone, with a wide range up to year 9999. TIMESTAMP is converted to UTC on write and back to the session time zone on read, but only spans 1970 to 2038. Q: Should I use VARCHAR or TEXT? A: Use VARCHAR for short, bounded strings that you may want to index fully; it is stored inline in the row. Use TEXT for long content — it can be stored off-page and has length limits up to 4 GB for LONGTEXT, but indexes need a prefix length. Q: Why use DECIMAL for money instead of FLOAT? A: FLOAT and DOUBLE are binary floating point and cannot represent many decimal fractions exactly, causing rounding errors. DECIMAL(M,D) stores the exact value, so it is the correct choice for currency and other exact figures. Q: What does UNSIGNED do? A: UNSIGNED removes the negative half of an integer type's range and doubles the positive maximum. For example INT UNSIGNED goes from 0 to about 4.29 billion instead of roughly negative to positive 2.1 billion. Q: What happens to out-of-range values? A: In the default STRICT SQL mode, inserting an out-of-range or wrongly typed value raises an error and the statement fails. Without strict mode, MySQL would silently clamp or truncate the value and emit a warning. #### Protobuf Decoder (No Schema) URL: https://geratools.com/protobuf-decoder Free schema-less Protobuf decoder. Paste hex or base64 wire bytes and see every field number, wire type and plausible value interpretation, with embedded messages decoded recursively. 100% client-side. How to use: 1. Select the format: Choose Hex or Base64 to match how you captured the Protobuf bytes, for example from a gRPC request body. 2. Paste the wire bytes: Paste the raw payload. On hex input, whitespace, commas and a leading 0x are ignored. 3. Decode: Press Decode wire format to list each field number, its wire type, and every plausible value interpretation. FAQ: Q: How can it decode Protobuf without the .proto schema? A: The Protobuf wire format is self-describing enough to parse without a schema. Each field is a varint key holding the field number and wire type, followed by a payload. The tool reads those keys and shows every value the wire type could represent. Q: Why does one field show several interpretations? A: Without a schema the tool cannot know whether a varint is an int, a zigzag sint, a bool or an enum, so it shows all of them. A 64-bit field is shown as fixed64, sfixed64 and double, and you pick the one that fits your message. Q: Does it decode nested messages? A: Yes. Length-delimited fields are tried as embedded messages and decoded recursively when that succeeds, while also being offered as a UTF-8 string or raw bytes when those are plausible. Q: Can it recover the original field names? A: No. Protobuf does not put field names on the wire, only numbers. You can recover field numbers, wire types and values, but names require the original .proto definition. Q: Is the payload uploaded anywhere? A: No. Parsing happens entirely in your browser, which makes it safe to inspect captured API or gRPC traffic without sending it to a third party. #### Random JSON Schema Generator URL: https://geratools.com/random-json-schema-generator Generates valid JSON Schema (draft 2020-12) objects with random properties, types, formats, and constraints. Ideal for testing schema validation libraries, API documentation tools, and form generators. Runs entirely in your browser. How to use: 1. Set the property count: Choose how many properties the generated object schema should contain. 2. Choose options: Decide whether to include required fields, additionalProperties, and nested objects, then generate. 3. Copy the schema: Copy the resulting JSON Schema document and paste it into your validator, mock-data tool, or API documentation. FAQ: Q: Which JSON Schema draft does this target? A: The output uses the draft 2020-12 dialect, declared with the $schema keyword set to the official 2020-12 meta-schema URI. This is the current widely-supported draft used by OpenAPI 3.1 and most modern validators. Q: Is the generated schema actually valid? A: Yes. Every document is a well-formed object schema with a type, a properties map, and optionally a required array whose entries all exist in properties. It parses and validates as a real JSON Schema, so you can feed it straight into a validator. Q: What property types are produced? A: Properties are drawn from string (with formats like email, date-time, and uri, plus minLength and maxLength), integer and number (with minimum and maximum), boolean, array (with an items subschema), and nested object types when nesting is enabled. Q: Why generate random schemas? A: Random schemas exercise validation libraries, schema-to-form generators, fake-data producers, and documentation renderers across many shapes without hand-writing each one. They are useful for fuzzing and regression-testing tools that consume schemas. Q: Does this send data anywhere? A: No. The schema is built locally in JavaScript and serialised with JSON.stringify, so nothing is uploaded and it works offline. #### SQL Date/Time Functions Reference URL: https://geratools.com/sql-date-functions Cross-dialect SQL date/time function reference covering NOW, DATEADD, EXTRACT, DATE_TRUNC and format functions, with side-by-side syntax for MySQL, PostgreSQL, SQLite and SQL Server. How to use: 1. Search a date task: Type the operation you need such as add days, extract year or truncate to month to filter the list. 2. Pick your dialect: Choose MySQL, PostgreSQL, SQLite or SQL Server to highlight the exact syntax for your engine. 3. Mind the conventions: Check the note line for argument order, timezone behaviour and field-numbering quirks before you paste. FAQ: Q: Why do DATEADD and DATE_ADD differ? A: They are different vendor implementations of the same idea. SQL Server uses DATEADD(unit, n, date), MySQL uses DATE_ADD(date, INTERVAL n unit) and PostgreSQL uses plain interval arithmetic like date + INTERVAL '7 days'. The SQL standard never settled one spelling. Q: Does NOW() return UTC or local time? A: It depends on the engine and session settings. PostgreSQL now() respects the session time zone, MySQL NOW() uses the server time zone, and SQLite datetime('now') returns UTC unless you add the 'localtime' modifier. Q: How do I truncate a date to the start of the month? A: PostgreSQL has DATE_TRUNC('month', d) and SQL Server 2022+ has DATETRUNC(MONTH, d). MySQL has no equivalent, so you format to a fixed-day string like DATE_FORMAT(d, '%Y-%m-01'), and SQLite uses date(d, 'start of month'). Q: Why does day-of-week return different numbers? A: The numbering convention is not standard. MySQL DAYOFWEEK returns 1-7 with Sunday as 1, PostgreSQL and SQLite return 0-6 with Sunday as 0, and SQL Server depends on the SET DATEFIRST setting. Always normalise before comparing across engines. Q: Is anything sent to a server? A: No. This is a static reference rendered entirely in your browser. There is no database connection and nothing you type is transmitted or stored. #### SQL CREATE TABLE to JSON Schema URL: https://geratools.com/sql-to-json-schema Free in-browser converter that parses MySQL, PostgreSQL and SQLite CREATE TABLE statements and generates an equivalent JSON Schema (draft-07) or TypeScript interface. Maps SQL types to JSON types, marks NOT NULL columns as required and runs entirely on your device. How to use: 1. Paste your CREATE TABLE: Paste one or more SQL CREATE TABLE statements (MySQL, PostgreSQL or SQLite dialect) into the box. 2. Pick an output format: Choose JSON Schema draft-07 or a TypeScript interface; the column types are mapped automatically. 3. Copy the result: Read the generated schema, verify the required fields and type mappings, then copy it for use in your code. FAQ: Q: Which SQL dialects are supported? A: It handles the common subset of MySQL, PostgreSQL and SQLite CREATE TABLE syntax — quoted or unquoted identifiers, column types with size and precision, NOT NULL, DEFAULT and inline PRIMARY KEY. Vendor-specific extensions are ignored gracefully rather than failing. Q: How are SQL types mapped to JSON Schema? A: Integer types map to integer, numeric and floating types to number, text and character types to string with maxLength where a size is given, boolean to boolean, and date/time types to string with the appropriate format (date or date-time). Unknown types fall back to string. Q: How does it decide which fields are required? A: A column becomes a required property when it is declared NOT NULL or is the PRIMARY KEY, and does not have a DEFAULT that would let it be omitted on insert. Nullable columns are optional. Q: Does it handle multiple tables at once? A: Yes. Paste several CREATE TABLE statements and each one becomes its own JSON Schema object or TypeScript interface, named after the table. Q: Is my SQL sent anywhere? A: No. The parser and generator run entirely in your browser. Your schema and any sensitive column names never leave your device. #### SQLite Schema Viewer URL: https://geratools.com/sqlite-schema-viewer Inspect a SQLite database's schema in your browser: every CREATE TABLE, CREATE INDEX, CREATE VIEW and CREATE TRIGGER statement, plus a foreign-key count per table. Parsed locally from sqlite_master — no upload. How to use: 1. Open a database file: Choose a .db or .sqlite file. The schema is read locally in your browser. 2. Review the objects: Tables, views, indexes and triggers are grouped, each showing its original CREATE statement. 3. Check relationships: Tables with foreign keys are flagged with a count so you can spot relationships at a glance. FAQ: Q: Where does SQLite store its schema? A: Every SQLite database keeps its schema in a built-in table called sqlite_master, which has one row per table, index, view and trigger. Each row stores the object's name, type, root page and the exact CREATE statement used to define it. Q: Does this modify my database? A: No. The viewer is strictly read-only. It parses the file in memory in your browser to display the schema and never writes back or sends anything to a server. Q: How are foreign keys detected? A: Foreign keys are counted by scanning each table's CREATE statement for REFERENCES clauses. This gives a quick relationship indicator; the full constraint text is visible in the displayed CREATE TABLE statement. Q: Will it show indexes I didn't create explicitly? A: Auto-created indexes that back UNIQUE or PRIMARY KEY constraints are named like sqlite_autoindex_* and are hidden, while indexes you defined with CREATE INDEX are shown in full. #### SQLite to CSV Exporter URL: https://geratools.com/sqlite-to-csv Export any table from a SQLite database to a CSV file entirely in your browser. Pick a table, get a properly quoted CSV download with header row and escaped values. No server, no upload — your data stays on your device. How to use: 1. Open the database: Choose a .db or .sqlite file. It is parsed locally in your browser. 2. Choose a table: Select the table you want to export from the dropdown of user tables. 3. Download the CSV: Click Export to generate and download a CSV file containing every row of that table. FAQ: Q: Does this export every row or just a preview? A: It exports the complete table. The tool walks the entire b-tree for the chosen table, decoding every row, then streams the result into a downloadable CSV Blob — there is no row cap. Q: How are commas, quotes and newlines handled? A: Values containing a comma, double quote or line break are wrapped in double quotes, and any internal double quotes are doubled, following RFC 4180. This keeps the CSV valid in Excel, Sheets and pandas. Q: Is my database uploaded? A: No. The file is read with the FileReader API and parsed in memory in your browser using a pure-JS SQLite reader. The CSV is generated client-side, so nothing is sent to a server. Q: How are NULL values and numbers exported? A: NULL becomes an empty field, integers and floats are written as plain numbers, and text is written verbatim with escaping. BLOB columns are written as a short size placeholder rather than raw binary. #### SQLite Database Viewer URL: https://geratools.com/sqlite-viewer Open a SQLite database file in your browser, list every table and view, and preview rows without installing a desktop GUI. The file is parsed locally using a pure-JS reader, so your data never leaves your device. How to use: 1. Open a database file: Choose a .db, .sqlite or .sqlite3 file. It is read locally in your browser. 2. Pick a table: All user tables are listed as buttons. Click one to load a preview of its rows. 3. Browse the data: The first 200 rows are shown in a scrollable grid with column headers parsed from the schema. FAQ: Q: How can a browser open a SQLite file without a server? A: The SQLite on-disk format is fully documented and stable. This tool implements a reader in JavaScript that parses the file header, walks the table b-trees and decodes each record, all in the browser — no WebAssembly engine or upload needed. Q: Is my database uploaded anywhere? A: No. The file is loaded with the FileReader API and parsed in memory on your device. Nothing is transmitted to a server, which matters for databases that contain personal or proprietary data. Q: Why are only 200 rows shown? A: The preview is capped at 200 rows per table to keep the interface responsive on large databases. To export every row of a table, use the companion SQLite to CSV exporter. Q: Are very large rows or BLOBs fully displayed? A: Large rows that spill onto overflow pages are read up to the page boundary, and BLOB columns are shown as a size placeholder rather than raw bytes. Text and numeric columns are decoded in full. #### tsconfig.json Options Reference URL: https://geratools.com/tsconfig-options-reference Searchable tsconfig.json compilerOptions reference. Each flag lists its value type, default, category, whether it is enabled by strict mode, and what it changes about type-checking or JavaScript emit. How to use: 1. Search an option: Type a flag name such as strictNullChecks or moduleResolution to filter the reference list to matching compiler options. 2. Read its effect: Each entry shows the value type, default, and a plain-language description of how the option changes type-checking or the emitted JavaScript. 3. Filter to strict flags: Choose the Strict family to see only the options that strict mode turns on, so you know exactly what enabling strict implies. FAQ: Q: What does the strict flag actually enable? A: Setting strict to true turns on a family of stricter checks at once: noImplicitAny, strictNullChecks, strictFunctionTypes, strictBindCallApply, strictPropertyInitialization, noImplicitThis, useUnknownInCatchVariables, and alwaysStrict. You can still override any individual member afterward. Q: Difference between target and module? A: target controls which JavaScript language features are downleveled, for example whether async/await becomes a state machine. module controls the module system of the emitted code, such as ESNext, CommonJS, or NodeNext. They are independent and frequently set to different values. Q: What does noUncheckedIndexedAccess do? A: It makes indexed access like arr[i] or record[key] return T | undefined instead of T, forcing you to handle the possibility that the element is missing. It is not part of strict, so you opt in separately for stronger safety on arrays and maps. Q: When should I use moduleResolution bundler? A: Use the bundler resolution mode when a bundler such as Vite, esbuild, or webpack resolves your imports. It allows extensionless imports and respects the exports field without the stricter rules of NodeNext, which suits browser app projects. Q: What does isolatedModules enforce? A: It requires every file to be compilable on its own, which is what single-file transpilers like Babel, esbuild, and SWC need. It bans constructs that need whole-program type information, such as re-exporting a type without the import type syntax or using const enums across files. #### Protobuf Varint Encoder/Decoder URL: https://geratools.com/varint-encoder Encode and decode unsigned integers in the Protocol Buffers varint (base-128) wire format. See the exact hex bytes a protobuf message would use, with BigInt precision for 64-bit values. Runs entirely in your browser. How to use: 1. Choose encode or decode: Select encode to turn an integer into varint bytes, or decode to turn bytes back into a number. 2. Enter the value: For encoding type a non-negative integer. For decoding paste the bytes in hex or decimal separated by spaces or commas. 3. Inspect the bytes: Encoding shows the hex byte sequence and how many bytes it took. Decoding shows the reconstructed integer. FAQ: Q: What is a protobuf varint? A: A varint is the variable-length integer encoding used in the Protocol Buffers wire format. Small numbers take a single byte while larger numbers grow one byte at a time, which keeps serialized messages compact. Q: How is a varint laid out in bytes? A: Each byte stores 7 bits of the value plus a high continuation bit. The least significant 7 bits come first (little-endian). Every byte except the last has its continuation bit set, so the decoder knows when to stop. Q: Is protobuf varint the same as LEB128? A: The unsigned encoding is byte-for-byte identical to unsigned LEB128. The difference is conventional usage: protobuf pairs varints with ZigZag encoding for signed fields rather than using a signed varint directly. Q: Why does 300 take two bytes? A: 300 in binary is 100101100, which needs more than 7 bits. The low 7 bits (0101100) go in the first byte with the continuation flag set, and the remaining bits (10) go in the second byte, giving AC 02 in hex. Q: Can it handle 64-bit values? A: Yes. The tool uses JavaScript BigInt internally, so values up to and beyond 64 bits encode and decode exactly without floating-point rounding. #### XLSX to CSV Converter URL: https://geratools.com/xlsx-to-csv Free XLSX to CSV converter. Upload an Excel .xlsx workbook and export any sheet as RFC-4180 CSV with your chosen delimiter. Shared strings, inline strings, numbers and booleans are resolved in your browser with no library and nothing uploaded. How to use: 1. Choose your workbook: Select an .xlsx file. It is read and decompressed entirely in your browser, so nothing is sent to a server. 2. Pick a sheet and delimiter: If the workbook has several sheets, choose which one to export, then select comma, semicolon, tab or pipe as the delimiter. 3. Copy or download the CSV: Read the converted CSV, copy it, or download a .csv file named after the workbook and sheet. FAQ: Q: How can it read .xlsx without Excel or a library? A: An .xlsx file is a ZIP archive of XML parts. The tool reads the ZIP directly and inflates each part using the browser's built-in DecompressionStream, then parses the worksheet XML and the shared-string table. No spreadsheet library is loaded. Q: Which cell types are handled? A: Shared strings, inline strings, plain string cells, numbers and booleans. Shared-string indices are resolved against the sharedStrings table so text appears correctly, and boolean cells are emitted as TRUE or FALSE. Q: Does it handle multiple sheets? A: Yes. Every worksheet is parsed and you can switch between them with a dropdown. Each sheet exports to its own CSV, since CSV is a single-table format and cannot hold more than one sheet at once. Q: What about formulas and formatting? A: CSV is plain text, so formatting, colours and merged-cell styling are dropped. Formula cells export their last calculated value, which Excel stores alongside the formula, so you get the result rather than the formula text. Q: Is my spreadsheet uploaded? A: No. The workbook is read, decompressed and parsed entirely on your device with JavaScript and Web APIs. Your data never leaves the browser, so confidential spreadsheets stay private. #### YAML Formatter & Re-indenter URL: https://geratools.com/yaml-formatter Free online YAML formatter. Expand tabs to spaces, normalise indentation to 2 or 4 spaces and tidy key/value spacing. Privacy-first — your YAML never leaves your browser. How to use: 1. Paste your YAML: Drop your YAML configuration or document into the input box. 2. Pick an indent and format: Choose 2 or 4 spaces and click Format. Tabs are expanded to spaces and every nesting level is snapped to a consistent indent. 3. Copy the result: Click Copy to put the re-indented YAML on your clipboard. FAQ: Q: Is my YAML uploaded anywhere? A: No. The formatter is plain JavaScript that runs entirely in your browser. Your YAML is never sent to a server. Q: How accurate is the re-indentation? A: The tool detects your source indentation step, snaps every line to a consistent normalised level, expands tabs to spaces (YAML disallows tab indentation) and tidies the spacing after a key colon and after list dashes. Block scalars (| and >) are preserved verbatim. It re-indents rather than fully parsing the document, so it does not detect every structural error. Q: Will it change my data? A: No. Only indentation and the spacing around colons and list dashes are normalised. Keys, values and block-scalar contents are kept as written. Q: Why are tabs a problem in YAML? A: The YAML specification forbids tab characters for indentation — only spaces are legal. A stray tab causes a parse error in most loaders, so the formatter expands every tab to two spaces before re-indenting. Q: Does it preserve multi-line block scalars? A: Yes. Content inside a `|` (literal) or `>` (folded) block scalar is more indented than its key and is copied verbatim, so the line breaks and internal spacing of embedded scripts or text blocks are not disturbed. Q: Does this validate my YAML? A: No. It re-indents and tidies spacing rather than parsing the document into a data model, so it will not catch every structural error. To check validity, run the YAML to JSON converter — a parse error there means the structure is wrong. Q: How does it decide the original indent step? A: It scans the leading-space depth of every non-blank line and takes the smallest positive difference between distinct depths as your source step, defaulting to 2 when ambiguous. Each level is then snapped to your chosen 2- or 4-space unit. #### Video Schema Generator URL: https://geratools.com/video-schema-generator Free video schema generator. Build a valid schema.org/VideoObject JSON-LD block — including duration, clips, publisher, interaction counts — and paste it straight into your page head. 100% client-side, nothing uploaded. How to use: 1. Enter the required video details: Fill in the video title, description, thumbnail URL, upload date, and duration. At least one of Content URL or Embed URL is also required. 2. Add optional metadata: Switch to the Optional tab to add publisher information, author, view count, language, regional restrictions, and boolean flags. 3. Add clip chapters: Switch to the Clips tab and add named sections with start/end offsets in seconds. These map to schema.org/Clip and enable chapter-level rich results. 4. Copy or download the output: Click Copy to grab the JSON-LD, or toggle the script-tag wrapper and download as .html. Paste into the head element of the page that hosts your video. FAQ: Q: What is VideoObject structured data and why does it matter? A: schema.org/VideoObject is a type of JSON-LD structured data that tells search engines — Google, Bing, and AI-powered assistants — exactly what your video is about: its title, description, duration, upload date, and more. When Google can parse this markup, your video becomes eligible for rich results in both the standard web index and the dedicated Video tab. Rich results typically show a thumbnail, title, duration badge, and upload date directly in the SERP — dramatically improving click-through rates compared to a plain blue link. Q: What fields are required by Google? A: Google requires at minimum: name, description, thumbnailUrl, and uploadDate. You also need at least one of contentUrl (a direct video file URL) or embedUrl (an iframe embed URL such as a YouTube embed link). Duration is strongly recommended and marked required in this tool because videos without it rarely receive the duration badge in rich results. Q: How do I format the duration correctly? A: Video duration must follow ISO 8601 duration format: PT(hours)H(minutes)M(seconds)S. For example, a 12-minute 30-second video is PT12M30S; a 1-hour 5-minute video is PT1H5M. This tool builds the ISO string automatically from the hours/minutes/seconds fields — you never need to type it manually. Q: What are Clips and do I need them? A: Clips (schema.org/Clip, listed as hasPart on the VideoObject) let you mark named chapters with a start and end offset in seconds. When Google indexes clips, it can show chapter-level timestamp links directly under the video result — the same feature visible on YouTube videos. Clips are optional but can increase engagement by letting viewers jump to the exact section they want. Q: Where exactly do I paste the JSON-LD script tag? A: Paste the generated script tag inside the head element of the page that embeds or hosts the video. One VideoObject per page — if you have a dedicated video landing page and also embed the video elsewhere, only the primary page (usually the canonical URL) should carry the schema. WordPress users can use a plugin such as Rank Math or Yoast, or add it via a custom HTML widget. Next.js users can inject it via a Script component with strategy="afterInteractive" or directly in the document head. Q: Can I use this schema for YouTube embeds? A: Yes. Set the Embed URL field to your YouTube embed URL (https://www.youtube.com/embed/VIDEO_ID) and leave Content URL blank, or populate both if you host a direct copy of the file. YouTube already generates its own VideoObject markup for videos hosted on youtube.com, but for embedded videos on your own domain you should add your own schema so that Google can attribute the video page on your site as the canonical reference. Q: Does this tool validate against the Google Rich Results spec? A: The tool validates that all fields Google marks as required are present and that URLs start with http/https. For a definitive machine check, paste the generated output into the Google Rich Results Test (search.google.com/test/rich-results). This catches additional issues such as unreachable thumbnail URLs or malformed date strings that a client-side tool cannot detect without network access. #### Local Business Schema Generator URL: https://geratools.com/local-business-schema-generator Build complete, valid JSON-LD structured data for any local business: restaurant, salon, clinic, hotel, shop, and 80+ other types. Includes opening hours builder, geo coordinates, aggregate ratings, payment methods and social profiles. Runs entirely in your browser. How to use: 1. Select your business type: Choose the most specific schema.org type from the dropdown (e.g. Restaurant, Dentist, HairSalon). Google uses the type to decide which rich-result features to unlock. 2. Fill in basic information: Enter your business name (required), website URL, description, logo, and cover image. Add your price range using the quick-select buttons. 3. Add your address and geo coordinates: Complete the address fields. For best local ranking, also add your precise latitude and longitude — right-click your pin on Google Maps to copy them. 4. Set your opening hours: Toggle each day on or off and pick opening and closing times. Days with identical hours are automatically merged into a single node in the output. 5. Add ratings, payments, and social links: Optionally fill in your aggregate rating (from verified reviews), accepted payment methods, social profile URLs, and service areas. 6. Copy or download the output: Click "Wrap in script tag" then Copy. Paste the snippet inside the head element of every page that represents the business. Validate with the Google Rich Results Test. FAQ: Q: What is LocalBusiness JSON-LD and why does my site need it? A: JSON-LD is a way to embed machine-readable data inside your HTML without touching the visible markup. When you add a LocalBusiness block, search engines like Google can extract your name, address, phone, hours, and rating and display them directly in search results as a knowledge panel, map pack entry, or rich snippet. This improves click-through rates and helps Google trust that the information on your page matches your Google Business Profile. Q: Which schema.org type should I choose? A: Always pick the most specific type available. A coffee shop should use CafeOrCoffeeShop rather than FoodEstablishment or the generic LocalBusiness, because specificity unlocks additional rich-result features. The generator lists 80+ types. If none fits exactly, fall back to LocalBusiness and rely on your description field. Q: How is OpeningHoursSpecification formatted? A: Each open day produces a node with dayOfWeek (e.g. "https://schema.org/Monday"), opens (e.g. "09:00") and closes (e.g. "17:00"). The generator automatically groups consecutive days with identical hours into a single node, keeping the output concise. Days marked Closed are omitted entirely. Q: Do I need to add geo coordinates (latitude and longitude)? A: They are optional in the schema spec but strongly recommended for local SEO. Precise coordinates help Google resolve your business location unambiguously and improve your ranking in map-pack results. To find them, right-click your location pin on Google Maps and copy the two decimal numbers shown at the top of the context menu. Q: Is it safe to add an aggregateRating? A: Yes, provided the rating reflects genuine, verifiable reviews from real customers. Google explicitly warns against self-authored or fabricated ratings and may apply a manual penalty if it finds them. Only fill in the rating fields if your average and review count are sourced from a legitimate review platform (e.g. Google Reviews, Trustpilot, Tripadvisor). Q: Where exactly do I paste the generated script tag? A: Inside the head element of your page is the most reliable location. It can also go just before the closing body tag. The important rule is that it appears only once per page and that the @type and name values match the content of the page it appears on. For multi-location businesses, add a separate schema block on each location's dedicated page. ### Encoding & Crypto #### ANSI Escape Codes URL: https://geratools.com/ansi-escape-codes Searchable ANSI/VT100 escape sequence reference covering CSI cursor moves, erase commands, SGR text modes, screen buffer and OSC sequences, with copyable literal bytes and examples. How to use: 1. Search a behaviour: Type what you want to do such as cursor, clear or title to filter the sequence list. 2. Filter by category: Use the category dropdown to focus on Cursor, Erase, Mode, Screen or OSC sequences. 3. Copy the sequence: Click Copy to put the sequence on your clipboard with a real ESC byte already substituted. FAQ: Q: What is the ESC character in an ANSI sequence? A: ESC is the escape control character, decimal 27 or hex 0x1B. Most ANSI sequences start with ESC followed by '[' to form a Control Sequence Introducer (CSI). In code it is often written as \e, \033 or \x1b. Q: What is the difference between CSI and OSC sequences? A: CSI sequences begin with ESC [ and control cursor movement, erasing and text attributes. OSC (Operating System Command) sequences begin with ESC ] and handle things like the window title and hyperlinks, terminated by BEL or a string terminator. Q: How do I clear the terminal screen with ANSI? A: Send ESC[2J to erase the whole screen, often combined with ESC[H to move the cursor to the top-left. Many tools also send ESC[3J to clear the scrollback buffer. Q: Why does {n} appear in some sequences? A: {n} is a numeric parameter you provide. For example ESC[5A moves the cursor up 5 rows. If you omit the number, most terminals default it to 1. Q: How do I use these sequences in a shell script? A: Use printf with an escape, for example printf '\033[2J' to clear the screen, or bash ANSI-C quoting like $'\e[1m' for bold. The Copy button already inserts the real ESC byte for you. #### Backslash Escaper & Unescaper URL: https://geratools.com/backslash-escape Free backslash escape tool — convert newlines, tabs, nulls and other control characters to C-style sequences like \n, \t and \xHH, and reverse it. Runs entirely in your browser. How to use: 1. Choose escape or unescape: Pick whether to add backslash sequences or interpret existing ones back into raw characters. 2. Enter your text: Paste raw text to escape, or paste already-escaped text to turn the sequences back into characters. 3. Copy the result: The output updates instantly. Click Copy to grab it for your code or config file. FAQ: Q: What characters get escaped? A: Control characters become readable sequences: newline as \n, tab as \t, carriage return as \r, null as \0, plus \v, \f and \b. Any other character below code point 32 (and DEL, 0x7f) becomes \xHH. Backslash, single quote and double quote are also escaped. Q: What is the difference between escaping and unescaping? A: Escaping turns invisible or special characters into printable backslash text so the string is safe to embed in source code. Unescaping does the reverse, converting \n back into an actual newline and so on. Q: Does it handle hex and Unicode escapes when unescaping? A: Yes. When unescaping it recognises \xHH (two hex digits) and \uXXXX (four hex digits) as well as the common single-letter escapes. Invalid or incomplete sequences are left as-is so nothing is corrupted. Q: Is this the same as JSON or URL escaping? A: No. This is C-style backslash escaping used by C, C++, Java and many config formats. JSON uses a similar but stricter set, and URL encoding uses percent signs instead of backslashes. Q: Is my text uploaded anywhere? A: No. All escaping and unescaping happens locally in your browser with JavaScript, so your text never leaves your device. #### Base32 Crockford Encoder/Decoder URL: https://geratools.com/base32-crockford Free Crockford Base32 encoder and decoder — uses the 0-9 A-Z alphabet minus I, L, O and U so encoded strings are easy to read aloud and type. Case-insensitive decoding with O→0 and I/L→1, all in your browser. How to use: 1. Choose encode or decode: Pick whether to convert text into Crockford Base32 or decode Base32 back to text. 2. Enter your data: For encoding, type any text. For decoding, paste a Crockford string — hyphens and spaces are ignored. 3. Copy the result: The output updates instantly. Click Copy to grab it. Invalid symbols are flagged with a clear message. FAQ: Q: How is Crockford Base32 different from standard Base32? A: It uses the alphabet 0–9 and A–Z but removes the four visually confusing letters I, L, O and U. That leaves 32 symbols chosen so encoded values are easy to read aloud, write down, and type without errors. Q: Why are I, L, O and U excluded? A: I and L look like the digit 1, O looks like 0, and U was dropped partly to avoid accidental profanity. Removing them makes the encoding far more robust for human transcription. Q: Is decoding case-insensitive? A: Yes. Crockford Base32 treats upper and lower case the same, and it also forgives common mistakes by mapping O to 0 and both I and L to 1 on input, so hand-copied strings still decode correctly. Q: Does this tool add padding? A: No. The Crockford specification does not use the = padding characters found in RFC 4648 Base32, so output is emitted without any trailing padding. Q: What is Crockford Base32 used for? A: It is popular for short, human-readable identifiers — ULIDs, license keys, coupon codes and account references — anywhere a value might be read over the phone or typed by hand. #### Base58 Flickr Encoder/Decoder URL: https://geratools.com/base58-flickr Encode and decode with Flickr's Base58 alphabet, which orders lowercase letters before uppercase to build the short photo-URL IDs behind flic.kr links. Handles integers and UTF-8 bytes with big-integer base conversion, all in your browser. How to use: 1. Choose encode or decode: Pick Encode to produce a Flickr Base58 string, or Decode to convert one back to a number or text. 2. Pick the data type: Choose Integer for photo-ID style numbers, or UTF-8 text/bytes for arbitrary data, then enter your value. 3. Read and copy the result: The converted value appears instantly and can be copied with one click. FAQ: Q: How is the Flickr alphabet different from Bitcoin's Base58? A: Both alphabets contain the same 58 characters and both omit the look-alikes zero, capital O, capital I and lowercase L. The difference is ordering: Flickr lists the digits, then lowercase letters, then uppercase letters, whereas Bitcoin lists digits, then uppercase, then lowercase. The same number therefore produces different strings in each scheme. Q: What does Flickr use Base58 for? A: Flickr assigns each photo a large numeric ID and encodes that integer in Base58 to make the short flic.kr URLs. Base58 keeps the slug compact while avoiding characters that are easy to misread or that need escaping inside a URL. Q: Should I use integer mode or text mode? A: Use integer mode when you have a numeric ID such as a photo ID, because Flickr encodes the number itself. Use text or bytes mode when you want to round-trip arbitrary data through the same alphabet, which preserves leading zero bytes as leading ones. Q: Why does decoding a slug give a huge number? A: Base58 represents a single large integer, so decoding a multi-character slug in integer mode reconstructs that big number. For photo IDs this is exactly the original numeric ID Flickr started with before encoding. Q: Does any data leave my browser? A: No. All conversions run locally in JavaScript, so your IDs and data are never uploaded anywhere. #### Base64 Encoder/Decoder with Binary Safety URL: https://geratools.com/base64-encoder-decoder Encode UTF-8 text or hex bytes to standard Base64 or URL-safe Base64url, and decode either variant back to text. Binary-safe via TextEncoder, detects non-UTF-8 output, and recognises JWT, PEM, and data-URI payloads. Runs entirely in your browser. How to use: 1. Pick a mode: Choose Encode to turn text or hex into Base64, or Decode to turn Base64 back into readable text. 2. Choose the variant: When encoding, select standard Base64 or URL-safe Base64url, which swaps plus and slash for dash and underscore and drops padding. 3. Read and copy the result: The converted value appears instantly. Non-UTF-8 decodes fall back to a hex view, and JWT, PEM, and data-URI inputs are flagged. FAQ: Q: What is the difference between Base64 and Base64url? A: Standard Base64 uses the characters plus and slash and pads with the equals sign, which can break inside URLs and filenames. Base64url replaces plus with dash and slash with underscore and omits padding, so the result is safe to drop into a URL or JWT segment. Q: Why does encoding emoji work here but not with plain btoa? A: The browser's btoa only accepts Latin-1 characters and throws on anything outside that range. This tool encodes through TextEncoder first, converting text to UTF-8 bytes, so emoji and all non-ASCII characters round-trip correctly. Q: What happens if I decode something that is not text? A: If the decoded bytes are not valid UTF-8 — for example a compressed file or an image — the tool detects that the strict decode failed and shows the raw bytes as hexadecimal instead of garbled characters. Q: Can I decode a JWT with this tool? A: A JWT is three Base64url segments joined by dots. Paste a single segment (the header or the payload) to decode it. The tool recognises the JWT pattern and reminds you to decode each segment separately. Q: Is anything I paste sent to a server? A: No. All encoding and decoding happens in JavaScript in your browser, so you can safely process secrets, tokens, and private data without it ever leaving your device. #### Base64 File Encoder / Decoder URL: https://geratools.com/base64-file-encoder Free Base64 file encoder and decoder. Convert any file to a base64 string or data URI, or decode base64 back to the original file, entirely in your browser with FileReader. No upload, nothing leaves your device. How to use: 1. Pick a mode: Choose Encode to turn a file into base64, or Decode to turn base64 back into a downloadable file. 2. Provide the input: Select a file to encode, or paste a base64 string or data URI to decode. 3. Copy or download: Copy the base64 string or data URI to your clipboard, or download the decoded file with the name you choose. FAQ: Q: What is the difference between the base64 string and the data URI? A: The data URI is the full value, like data:image/png;base64,AAAA..., including the MIME type prefix. The base64 string is only the payload after the comma. Use the data URI for inline src/href attributes and the bare payload when an API expects just base64. Q: Why is the base64 larger than my original file? A: Base64 encodes every 3 bytes as 4 ASCII characters, so the output is about 33% larger than the source. The tool shows the exact size overhead for your file. Q: Is my file uploaded anywhere? A: No. Encoding uses the browser's FileReader and decoding uses atob, both running locally. Your file and its contents never leave your device. Q: Can I decode a full data URI, not just the payload? A: Yes. If you paste a value starting with data:, the tool strips the prefix automatically before decoding. It also tolerates URL-safe base64 and whitespace. Q: What name does the decoded file get? A: You choose the output file name before downloading. Because raw base64 carries no file name or extension, set the correct extension yourself (for example .png or .pdf) so your system opens it properly. #### Base64 Variants Reference URL: https://geratools.com/base64-variants Reference and live encoder for Base64 variants: RFC 4648 standard and URL-safe alphabets, MIME line-wrapping, IMAP modified base64 and a base32 comparison, showing how the same input encodes under each. How to use: 1. Type some input: Enter any text in the box to see it encoded live under each Base64 variant. 2. Compare the alphabets: Each row shows how characters 62 and 63 differ (+ / vs - _) and how padding is handled. 3. Copy a result: Use the copy button next to any variant to put its encoded output on your clipboard. FAQ: Q: What is the difference between standard and URL-safe Base64? A: Both use the same 64-symbol scheme, but standard Base64 (RFC 4648 §4) uses + and / for values 62 and 63, while URL-safe Base64 (§5) uses - and _ so the output is safe in URLs and filenames without percent-encoding. Q: Why does Base64 use = padding? A: Base64 encodes 3 input bytes into 4 characters. When the input length is not a multiple of 3, one or two = characters pad the final group so the output length is a multiple of 4. Some variants omit padding entirely. Q: What is MIME Base64? A: MIME Base64 (RFC 2045) uses the standard alphabet but wraps the output into lines of at most 76 characters separated by CRLF, and decoders must ignore characters outside the alphabet, including the line breaks. Q: What is modified Base64 for IMAP? A: IMAP's UTF-7 mailbox names (RFC 3501) use a modified Base64 that keeps + and replaces / with a comma, and omits padding. It encodes only the non-ASCII portions of mailbox names between & and - delimiters. Q: How much larger is Base64 output than the input? A: Base64 expands data by about 33%, since every 3 bytes become 4 characters. With padding and MIME line breaks the overhead is slightly higher. Base32 expands more, by about 60%. #### CRC-16/Modbus Checksum Calculator URL: https://geratools.com/checksum-crc16-modbus Calculate the CRC-16/Modbus checksum used in industrial Modbus RTU communications. Enter text or hex bytes and get the hex, decimal, and on-the-wire low/high byte order instantly in your browser. How to use: 1. Pick an input mode: Choose Text to checksum a UTF-8 string, or Hex bytes to paste a raw Modbus frame as hex pairs. 2. Enter the data: Type or paste the bytes. Separators like spaces, commas, and colons are ignored in hex mode. 3. Read the CRC: The tool shows the CRC-16/Modbus value in hex and decimal, plus the low-byte-first order Modbus RTU puts on the wire. FAQ: Q: What CRC parameters does Modbus use? A: Modbus RTU uses CRC-16 with the reflected polynomial 0xA001 (the bit-reversal of 0x8005), an initial value of 0xFFFF, reflected input and output, and no final XOR. These parameters are fixed by the Modbus specification. Q: How can I verify the calculator is correct? A: The canonical check string "123456789" must produce 0x4B37 under CRC-16/Modbus. This tool returns exactly that value, which confirms the polynomial and reflection are implemented correctly. Q: In what byte order is the CRC sent in a Modbus frame? A: Modbus RTU appends the CRC low byte first and the high byte second, unlike most multi-byte fields in the protocol. The tool shows this on-the-wire order separately so you can build frames directly. Q: Is this CRC suitable for security? A: No. CRC-16/Modbus only detects accidental transmission errors such as noise or dropped bits. It offers no protection against deliberate tampering — use an authenticated MAC for that. Q: Why does my result differ from a generic CRC-16 tool? A: There are many CRC-16 variants. CRC-16/CCITT uses polynomial 0x1021 and gives 0x29B1 for the check string, while CRC-16/Modbus uses 0xA001 and gives 0x4B37. Make sure you are comparing the same variant. #### CRC-16 Checksum Calculator URL: https://geratools.com/checksum-crc16 Free CRC-16 checksum calculator using the CRC-16/CCITT-FALSE variant (polynomial 0x1021, init 0xFFFF) on text or raw hex bytes, in hex and decimal. Runs entirely in your browser in pure JavaScript; nothing is uploaded. How to use: 1. Choose an input mode: Select Text to checksum a UTF-8 string, or Hex bytes to checksum raw byte values like 31 32 33. 2. Enter your data: Type or paste your text or hex bytes. The CRC-16 updates live as you type. 3. Copy the result: The 16-bit CRC appears in hexadecimal and decimal — click Copy hex to copy it. FAQ: Q: Which CRC-16 variant does this use? A: It uses CRC-16/CCITT-FALSE: polynomial 0x1021, initial value 0xFFFF, no input or output reflection, and no final XOR. This is the variant most people mean by 'CRC-16 CCITT', used by XMODEM-style and many serial protocols. Q: How can I check the result is correct? A: The standard CRC check string is the ASCII text "123456789". For CRC-16/CCITT-FALSE it must produce 0x29B1. If your value matches, the implementation is working correctly. Q: Why are there so many CRC-16 variants? A: Different protocols chose different polynomials, initial values, reflection settings, and final XOR masks (CCITT, MODBUS, XMODEM, IBM, and more). They all use 16-bit arithmetic but produce different results, so you must match the exact variant your protocol specifies. Q: Is CRC-16 suitable for security? A: No. CRC-16 is an error-detection checksum that catches accidental corruption, not a cryptographic hash. It is easy to forge, so never use it to protect against deliberate tampering. #### CRC-32C (Castagnoli) Checksum URL: https://geratools.com/checksum-crc32c Calculate CRC-32C using the Castagnoli polynomial (0x1EDC6F41) used by iSCSI, SCTP, ext4, Btrfs, and hardware-accelerated storage. Enter text or hex bytes and read the result in hex and decimal in your browser. How to use: 1. Choose your input: Select Text to hash a UTF-8 string, or Hex bytes to paste a raw byte sequence. 2. Enter the data: Type or paste your content. In hex mode, spaces, commas, and colons between byte pairs are ignored. 3. Copy the checksum: Read the CRC-32C value as an eight-digit hex string and as an unsigned decimal, then copy it with one click. FAQ: Q: How is CRC-32C different from regular CRC-32? A: They use different generator polynomials. Standard CRC-32 (used by zlib, PNG, and Ethernet) uses 0x04C11DB7, while CRC-32C uses the Castagnoli polynomial 0x1EDC6F41. The polynomials produce completely different checksums for the same data. Q: What is the correct check value for CRC-32C? A: For the ASCII string "123456789", CRC-32C must produce 0xE3069283. This tool returns that exact value, confirming the Castagnoli polynomial, reflection, and final XOR are implemented correctly. Q: Where is CRC-32C actually used? A: It is the integrity check for iSCSI, SCTP, the ext4 and Btrfs filesystems, and many NVMe and storage paths. Modern x86 CPUs include an SSE 4.2 instruction that computes it in hardware, which is why it was chosen for high-throughput protocols. Q: Why are the parameters reflected? A: CRC-32C uses reflected input and output and an initial value of 0xFFFFFFFF with a final XOR of 0xFFFFFFFF. Reflection matches how data is shifted least-significant-bit first on the wire and lets the bytewise table method run efficiently. Q: Can CRC-32C detect malicious changes? A: No. Like all CRCs it only catches accidental corruption such as bit flips or dropped bytes. An attacker can craft data with any desired CRC, so use a cryptographic hash or MAC where tampering is a concern. #### CRC-64 Checksum Calculator URL: https://geratools.com/checksum-crc64 Free CRC-64 checksum calculator using the ECMA-182 polynomial (0x42F0E1EBA9EA3693) on text or raw hex bytes, with exact 64-bit BigInt math, in hex and decimal. Runs entirely in your browser; nothing is uploaded. How to use: 1. Choose an input mode: Select Text to checksum a UTF-8 string, or Hex bytes to checksum raw byte values like 31 32 33. 2. Enter your data: Type or paste your text or hex bytes. The CRC-64 updates live as you type. 3. Copy the result: The 64-bit CRC appears in hexadecimal and unsigned decimal — click Copy hex to copy it. FAQ: Q: Which CRC-64 variant does this use? A: It uses CRC-64/ECMA-182: polynomial 0x42F0E1EBA9EA3693, initial value 0, no input or output reflection, and no final XOR. This is the variant standardised by ECMA-182 and used for tape and large-file integrity. Q: How can I check the result is correct? A: The standard CRC check string is the ASCII text "123456789", which for CRC-64/ECMA-182 must produce 0x6C40DF5F0B497347. A matching value confirms the implementation is correct. Q: Why use CRC-64 instead of CRC-32? A: A 64-bit CRC has a far larger code space, so the probability of an undetected error in very large data sets is dramatically lower than with CRC-32. It is commonly used for tape archives, large file stores, and deduplication keys. Q: How is the 64-bit value computed in a browser? A: JavaScript numbers cannot hold 64-bit integers exactly, so this tool uses BigInt for all CRC arithmetic. That guarantees the full 64-bit result is exact rather than losing precision above 2^53. #### CRC32 Checksum Calculator URL: https://geratools.com/crc32-text Calculate the IEEE 802.3 CRC-32 of any text, encoded as UTF-8 bytes. Returns the 8-digit hex value and decimal form, computed entirely in your browser with the standard 0xEDB88320 reflected polynomial used by zlib, gzip, and PNG. How to use: 1. Enter your text: Type or paste the text you want to checksum into the input box. It is encoded as UTF-8 before the CRC is computed. 2. Read the CRC-32: The 8-digit hexadecimal checksum updates instantly, along with its decimal value and the UTF-8 byte length. 3. Copy the result: Click the copy button to put the hex checksum on your clipboard for use in a manifest, log, or comparison. FAQ: Q: Which CRC-32 variant does this use? A: It uses the IEEE 802.3 variant, the same one in zlib, gzip, PNG, and Ethernet. The reflected polynomial is 0xEDB88320, the initial value is 0xFFFFFFFF, and the result is XORed with 0xFFFFFFFF at the end. Q: Why does my checksum differ from another tool? A: Different CRC-32 variants exist (CRC-32C/Castagnoli, CRC-32/BZIP2, JAMCRC) with different polynomials or bit reflection. This tool implements the common zlib/IEEE variant. Also confirm both tools encode the text the same way; this one uses UTF-8. Q: Is CRC-32 a secure hash? A: No. CRC-32 detects accidental changes like transmission errors or corruption, but it is trivial to forge. Never use it for passwords, signatures, or security. Use SHA-256 or similar for those. Q: How is non-ASCII text handled? A: The input is encoded as UTF-8 first, so a character like é becomes two bytes (0xC3 0xA9) and a CJK character becomes three bytes. The checksum is computed over those raw bytes, and the tool shows the resulting byte length. Q: Does my text leave the browser? A: No. The CRC-32 is computed locally in JavaScript using a precomputed lookup table. Nothing is uploaded to a server, so it is safe for private or sensitive strings. #### Geohash to Lat/Lng Converter URL: https://geratools.com/geohash-to-lat-lng Decode a geohash string back to the center latitude and longitude plus the full bounding box of its cell. Implements the standard base-32 interleaved-bit decoding used for spatial indexing. How to use: 1. Paste the geohash: Enter a base-32 geohash such as gbsuv7ztq. Case is ignored. 2. Read the coordinates: The tool shows the cell center latitude and longitude plus its bounding box. 3. Copy the result: Use the copy button to grab the center lat, lng pair. FAQ: Q: What does decoding a geohash return? A: Decoding gives the cell that the geohash represents. The tool reports the geometric center as a single lat, lng and the four bounds that enclose the cell. Q: Why is there a bounding box rather than one point? A: A geohash always describes an area whose size depends on the string length. Shorter geohashes cover larger cells, so the bounding box tells you how much spatial uncertainty the code carries. Q: Which characters are valid? A: Geohash uses base-32 with the symbols 0-9 and b, c, d, e, f, g, h, j, k, m, n, p, q, r, s, t, u, v, w, x, y, z. The letters a, i, l and o are excluded, and any other character is rejected. Q: Does longer input give a more precise location? A: Yes. Each additional character shrinks the cell by roughly a factor of eight, so an 11 character geohash pins a location to a few metres while a 5 character one spans a few kilometres. Q: How accurate is the center coordinate? A: The center is exact for the decoded cell. The real point that produced the geohash lies somewhere inside the bounding box, so the center is the best single estimate. #### BLAKE2b Hash Generator URL: https://geratools.com/hash-blake2b Free online BLAKE2b hash generator with selectable output length up to 64 bytes. Compute the fast modern BLAKE2b digest of any text in your browser with a pure-JS implementation — no upload, no server. How to use: 1. Enter your text: Type or paste the string you want to hash into the input box. 2. Choose a digest length: Pick an output size from 1 to 64 bytes; 32 and 64 bytes are the most common. 3. Copy the result: The hexadecimal BLAKE2b digest updates live; click Copy to grab it. FAQ: Q: What is BLAKE2b? A: BLAKE2b is a fast cryptographic hash from RFC 7693, optimised for 64-bit platforms. It produces digests of any length from 1 to 64 bytes and is often faster than MD5 or SHA-1 while being far more secure. Q: How is BLAKE2b different from BLAKE2s? A: BLAKE2b uses 64-bit words and supports up to a 512-bit (64-byte) digest, suiting 64-bit CPUs. BLAKE2s uses 32-bit words with up to a 256-bit digest and targets 8 to 32-bit platforms. Q: Why can I pick the output length? A: BLAKE2b takes the desired digest length as a parameter mixed into its initial state, so a 32-byte digest is not simply a truncation of the 64-byte one — each length is a distinct, fully-mixed output. Q: Is my text uploaded? A: No. The hash runs entirely in your browser via a pure-JavaScript BLAKE2b implementation, so the input never leaves the page. #### BLAKE2s Hash Generator URL: https://geratools.com/hash-blake2s Free online BLAKE2s hash generator with selectable output length up to 32 bytes. Compute the fast modern BLAKE2s digest of any text in your browser with a pure-JS implementation — no upload, no server. How to use: 1. Enter your text: Type or paste the string you want to hash into the input box. 2. Choose a digest length: Pick an output size from 1 to 32 bytes; 32 bytes is the most common. 3. Copy the result: The hexadecimal BLAKE2s digest updates live; click Copy to grab it. FAQ: Q: What is BLAKE2s? A: BLAKE2s is the 32-bit variant of BLAKE2 from RFC 7693, tuned for 8 to 32-bit platforms and embedded systems. It produces digests from 1 to 32 bytes and is fast and secure. Q: How is BLAKE2s different from BLAKE2b? A: BLAKE2s uses 32-bit words, 64-byte blocks, 10 rounds, and a maximum 256-bit digest. BLAKE2b uses 64-bit words, 128-byte blocks, 12 rounds, and up to a 512-bit digest, which is faster on 64-bit CPUs. Q: Why can I choose the output length? A: The requested digest length is mixed into BLAKE2s's initial state, so a 16-byte digest is a distinct, fully-mixed hash rather than a truncation of the 32-byte output. Q: Is my text sent anywhere? A: No. The hash is computed entirely in your browser with a pure-JavaScript BLAKE2s implementation, so the input never leaves the page. Q: Can I use BLAKE2s to store passwords? A: No. Like all fast hashes, BLAKE2s is the wrong tool for password storage — its speed helps attackers brute-force. Use a slow, memory-hard KDF such as Argon2 (which uses BLAKE2 internally), scrypt, or bcrypt for credentials. BLAKE2s is for integrity and MACs, not passwords. Q: Do I need HMAC to authenticate a message with BLAKE2s? A: No. BLAKE2 has keyed mode built in, so BLAKE2s(key, message) is already a secure MAC. It is not vulnerable to the length-extension attacks that make HMAC necessary for SHA-2, so no HMAC wrapper is required. #### BLAKE3 Hash Generator URL: https://geratools.com/hash-blake3 Free BLAKE3 hash generator that computes the 256-bit (or longer XOF) BLAKE3 digest of any text. A faithful pure-JavaScript implementation of the tree-based hash — runs entirely in your browser, nothing is uploaded. How to use: 1. Enter your text: Type or paste the text you want to hash into the input box. It is encoded as UTF-8 bytes. 2. Choose an output length: Keep the default 256-bit output, or pick 128 or 512 bits to use BLAKE3 as an extendable-output function. 3. Copy the digest: The BLAKE3 hash appears live in hexadecimal as you type — click Copy digest to put it on your clipboard. FAQ: Q: Is my text sent to a server? A: No. The BLAKE3 digest is computed in pure JavaScript entirely in your browser. Your text never leaves your device and nothing is uploaded. Q: What is the BLAKE3 hash of an empty input? A: The BLAKE3 hash of the empty string is af1349b9f5f9a1a6a0404dea36dcc9499bcb25c9adc112b7cc9a93cae41f3262. You can use this as a reference value to confirm a BLAKE3 implementation is correct. Q: Why is BLAKE3 considered fast? A: BLAKE3 hashes data as a Merkle tree of 1024-byte chunks, so the work can be parallelised across cores and SIMD lanes. It also uses a reduced 7-round compression function, making it much faster than SHA-256 while remaining cryptographically strong. Q: Can BLAKE3 produce outputs longer than 256 bits? A: Yes. BLAKE3 is an extendable-output function (XOF): the root node is run with an increasing output counter to stream as many bytes as you want. This tool supports 128, 256, and 512-bit outputs from the same root. #### djb2 Hash Calculator URL: https://geratools.com/hash-djb2 Computes the classic djb2 string hash by Daniel J. Bernstein, including both the multiply-add and the xor variant, in hex and decimal. A simple fast non-cryptographic hash for strings. How to use: 1. Enter your text: Type or paste the string to hash; it is read as UTF-8 bytes. 2. Read both variants: The tool shows the classic add variant and the xor variant in hex and decimal. 3. Use the value: Copy the 32-bit result for use as a hash-table key or quick fingerprint. FAQ: Q: What is the djb2 hash? A: djb2 is a very simple string hash by Daniel J. Bernstein. It starts from the magic constant 5381 and, for each byte, computes hash = hash * 33 + byte. It is fast and surprisingly well-distributed for its size. Q: Why does djb2 start at 5381? A: 5381 is the empirically chosen seed Bernstein found gave good distribution. Combined with the multiplier 33, it spreads typical ASCII strings across the 32-bit space with few collisions. Q: What is the xor variant? A: The xor variant (sometimes called djb2a) replaces the addition with XOR, computing hash = hash * 33 ^ byte. It behaves similarly but mixes bits slightly differently; this tool shows both. Q: Why is multiply-by-33 written as a shift and add? A: Classic implementations use ((hash << 5) + hash) because that equals hash * 33 and was faster on older CPUs. The result is identical to a direct multiply by 33. Q: Is djb2 secure? A: No. djb2 is a non-cryptographic hash that is trivial to collide deliberately. Use it for hash tables and lightweight fingerprints, never for passwords, tokens or signatures. #### FNV-1a Hash Calculator URL: https://geratools.com/hash-fnv1a Computes the FNV-1a (Fowler-Noll-Vo) non-cryptographic hash of any text in both 32-bit and 64-bit variants, showing hex and decimal output. Ideal for hash tables, checksums and quick keying. How to use: 1. Enter your text: Type or paste the string you want to hash; it is encoded as UTF-8 bytes. 2. Read both variants: The tool shows the FNV-1a 32-bit and 64-bit hashes in hexadecimal and decimal. 3. Copy a value: Use the Copy button next to any result to put that hash on your clipboard. FAQ: Q: What is the FNV-1a hash? A: FNV-1a is a fast non-cryptographic hash by Fowler, Noll and Vo. For each input byte it XORs the byte into the hash and then multiplies by a fixed FNV prime, all modulo 2^32 or 2^64. Q: How does FNV-1a differ from FNV-1? A: FNV-1 multiplies first and then XORs each byte, while FNV-1a XORs first and then multiplies. The order swap in FNV-1a gives slightly better avalanche behaviour and is the more commonly used variant. Q: What are the FNV constants? A: The 32-bit variant uses offset basis 2166136261 and prime 16777619. The 64-bit variant uses offset basis 14695981039346656037 and prime 1099511628211. Q: Why does the 64-bit value use BigInt arithmetic? A: JavaScript numbers cannot represent 64-bit integers exactly, so the tool computes the 64-bit hash with BigInt masked to 2^64 to keep every bit correct. Q: Is FNV-1a safe for passwords? A: No. FNV-1a is non-cryptographic and easily reversible or collidable on purpose. Use it for hash tables and integrity hints only, never for passwords, tokens or signatures. #### Hash Identifier URL: https://geratools.com/hash-identifier Identify the likely algorithm behind a hash by its length, character set and prefix. Recognises bcrypt, Argon2, crypt(3), MD5, SHA family, NTLM and more, listing every plausible candidate. Runs entirely in your browser. How to use: 1. Paste the hash: Drop the hash string into the box. Leading and trailing whitespace is trimmed automatically. 2. Read the candidates: The tool reports the detected format and lists every algorithm that matches the length and character set. 3. Use the prefix when present: Prefixed formats like bcrypt or Argon2 are identified unambiguously; raw digests only narrow the field by length. FAQ: Q: How does hash identification work? A: Structured hashes such as bcrypt and Argon2 carry an explicit prefix, so they are matched exactly. Raw hex or Base64 digests have no label, so the tool infers candidates from the length in bits and the character set. Q: Why does it list several possible algorithms? A: Many algorithms produce the same output length. For example a 32-character hex string could be MD5, MD4, NTLM or MD2. Without context the length can only narrow the options, not pick one. Q: Can it tell bcrypt from a plain SHA hash? A: Yes. bcrypt strings start with $2a$, $2b$ or $2y$ followed by a cost and salt, which is unmistakable, whereas a bare SHA-256 digest is just 64 hex characters with no prefix. Q: Does identifying a hash help me crack it? A: No. This tool only classifies the format so you can choose the right verification routine. It does not reverse, crack or look up any hash, and salted or slow hashes like bcrypt are designed to resist cracking entirely. Q: Is my hash sent anywhere? A: No. All matching is done in your browser against built-in length and prefix rules, so the hash never leaves your device. #### MD5 Hash Generator URL: https://geratools.com/hash-md5 Generate the 128-bit MD5 hash of any text entirely in your browser. Useful for checksums and legacy compatibility, with a clear note that MD5 is not safe for passwords or security. How to use: 1. Type or paste text: Enter the text you want to hash into the input box. Hashing happens locally as you type. 2. Read the digest: The 32-character hexadecimal MD5 hash appears immediately below the input. 3. Copy the hash: Use the copy button to grab the digest for a checksum file, a cache key, or a legacy integration. FAQ: Q: What is an MD5 hash? A: MD5 is a hash function that turns any input into a fixed 128-bit value, shown as 32 hexadecimal characters. The same input always produces the same digest, which makes it useful for checksums. Q: Is MD5 secure for passwords? A: No. MD5 is cryptographically broken: collisions can be generated cheaply, so it must never be used for passwords, signatures, or any security-critical purpose. Use bcrypt or Argon2 for passwords instead. Q: Why does an empty input still produce a hash? A: MD5 is defined for any input length including zero bytes. The hash of an empty string is the well-known constant d41d8cd98f00b204e9800998ecf8427e, which confirms the implementation is working. Q: Is my text sent to a server? A: No. The MD5 computation runs entirely in your browser using JavaScript, so the text you enter never leaves your device. The page works even with your network disconnected. Q: What is MD5 still acceptable for? A: MD5 remains fine for non-security uses such as detecting accidental file corruption, deduplicating data, or generating cache keys, where an attacker is not trying to forge a matching input. #### MurmurHash3 Calculator URL: https://geratools.com/hash-murmur3 Computes the MurmurHash3 32-bit (x86) hash of any text with a configurable seed, returning hex and decimal output. The same well-distributed hash used by many databases, hash tables and bloom filters. How to use: 1. Enter your text: Type or paste the string to hash; it is read as UTF-8 bytes. 2. Set an optional seed: Enter an unsigned 32-bit seed, or leave it as 0 for the default. 3. Read the hash: The tool returns the 32-bit MurmurHash3 value in hexadecimal and decimal. FAQ: Q: What is MurmurHash3? A: MurmurHash3 is a fast non-cryptographic hash by Austin Appleby, designed for excellent distribution and speed. The 32-bit variant computed here is widely used in hash tables, bloom filters and sharding. Q: Which MurmurHash3 variant does this compute? A: It computes MurmurHash3_x86_32, the 32-bit little-endian variant. This is the most common form referenced simply as MurmurHash3 in libraries and databases. Q: What does the seed do? A: The seed initialises the hash state, so the same input produces different outputs for different seeds. Use a fixed seed when you need reproducible hashing, and vary it for independent hash functions. Q: How are leftover tail bytes handled? A: MurmurHash3 processes the input in 4-byte blocks; the remaining 1 to 3 bytes are mixed in a separate tail step before the final avalanche (fmix32). This tool implements that tail handling exactly. Q: Is MurmurHash3 cryptographically secure? A: No. MurmurHash3 is fast and well-distributed but not collision-resistant against an attacker. Use it for data structures, not for passwords, tokens or signatures. #### xxHash Calculator URL: https://geratools.com/hash-xxhash Computes XXH32 and XXH64 hashes of any text with an optional seed, returning hex and decimal output. The same blazing-fast non-cryptographic hash used by LZ4, Zstandard and many databases. How to use: 1. Enter your text: Type or paste the string to hash; it is encoded as UTF-8 bytes. 2. Set an optional seed: Enter an integer seed or leave it as 0; the 32-bit and 64-bit variants share it. 3. Read the hashes: The tool shows XXH32 in hex plus XXH64 in hex and decimal. FAQ: Q: What is xxHash? A: xxHash is a non-cryptographic hash by Yann Collet known for extreme speed, often saturating memory bandwidth. It is used inside LZ4, Zstandard and many databases for fast integrity checks and keying. Q: What is the difference between XXH32 and XXH64? A: XXH32 produces a 32-bit hash optimised for 32-bit platforms, while XXH64 produces a 64-bit hash and is typically faster and lower-collision on 64-bit systems. This tool computes both. Q: How does the seed affect the hash? A: The seed initialises the internal accumulators so the same input yields different outputs per seed. Keep the seed fixed for reproducible hashing or vary it for independent hash families. Q: Why is the 64-bit value computed with BigInt? A: A 64-bit hash needs exact 64-bit integer arithmetic, which standard JavaScript numbers cannot provide. The tool uses BigInt masked to 2^64 so every bit of XXH64 is correct. Q: Is xxHash suitable for security? A: No. xxHash is built for speed and distribution, not collision resistance against attackers. Use it for hash tables, deduplication and checksums, never for passwords or signatures. #### HTML Numeric Entity Encoder/Decoder URL: https://geratools.com/html-entity-numeric Encode any text as numeric HTML entities in decimal (&#160;) or hexadecimal (&#xA0;) form using Unicode code points, and decode numeric and named entities back to characters. Runs entirely in your browser. How to use: 1. Select mode and base: Choose Encode or Decode, and when encoding pick decimal or hexadecimal numeric references. 2. Enter text or entities: Paste the characters you want to encode, or the &#xNN; and &#NN; entities you want to decode. 3. Copy the output: The converted result appears immediately below the input; click Copy to grab it. FAQ: Q: What is the difference between decimal and hex entities? A: Both reference the same Unicode code point. A decimal entity writes the number in base 10, like   for a non-breaking space, while a hex entity writes it in base 16, like  . Browsers treat the two forms identically. Q: Does this handle characters above U+FFFF? A: Yes. Emoji and other astral-plane characters have a single code point above 65535, and the tool emits one numeric entity for the whole code point rather than splitting it into surrogate halves, which keeps the output correct and compact. Q: Can I encode only special characters? A: By default every character is converted so the output is fully ASCII-safe, which is useful for email and legacy systems. The named-entity tool is a better fit when you only want to escape markup-critical characters and keep text readable. Q: Will it decode named entities too? A: Decoding expands numeric decimal and hex references plus the five core named entities amp, lt, gt, quot, and apos, so mixed input round-trips cleanly. For the full named-entity table, use the dedicated named-entity decoder. Q: Why use numeric entities at all? A: They guarantee a character displays correctly even when the page encoding is uncertain or limited to ASCII. They are common in XML, email templates, and exported data where a reliable, encoding-independent representation is needed. #### HTML Entity & Unicode Escape Decoder URL: https://geratools.com/html-entity-privacy-decoder Decode HTML entities (&, ',  ), JavaScript \uXXXX and \xXX escapes, and URL percent-encoding all at once on pasted text. Security engineers use this to de-obfuscate XSS and injection payloads safely, without running untrusted strings through a live browser console. Everything runs locally. How to use: 1. Paste the encoded text: Paste the obfuscated or encoded string into the input box. It can mix HTML entities, backslash escapes, and percent-encoding. 2. Choose which layers to decode: Toggle HTML entities, JavaScript escapes, and percent-encoding on or off so you can peel obfuscation one layer at a time. 3. Read the decoded output: The decoded string appears instantly, with control and non-printing characters made visible so nothing hides in the result. FAQ: Q: Is it safe to decode an XSS payload here? A: Yes. The decoder only converts character escapes back to their literal characters using string operations and DOM text parsing. It never executes the payload as code, so a malicious script stays inert plain text. Q: What encodings does it handle? A: Named HTML entities (&), decimal and hex numeric entities (  /  ), JavaScript \uXXXX, \u{...}, and \xXX escapes, and URL percent-encoding (%20). You can decode all three layers in one pass or peel them individually. Q: Why decode in one pass? A: Real-world obfuscation often nests encodings — a percent-encoded HTML entity, for example. Decoding several layers at once, or repeatedly, reveals the underlying string faster than guessing which single decoder to apply. Q: How are HTML entities decoded without a browser console? A: The tool sets the encoded text as the textContent-equivalent of an in-memory element and reads back its decoded text. This uses the browser's own entity table but never inserts the value into the live page or runs it as HTML. Q: Does my pasted text leave the browser? A: No. All decoding is done locally in JavaScript. Nothing is uploaded, logged, or stored, which is why it is safe for sensitive or malicious sample payloads. #### Shapefile Viewer (SHP + DBF) URL: https://geratools.com/shapefile-viewer Free browser-based ESRI Shapefile viewer — drop a .shp and .dbf together to render point, line, and polygon geometry and inspect the dBASE attribute table. No GIS software, no upload; everything is parsed locally. How to use: 1. Select the files: Choose the .shp and its matching .dbf from the same shapefile in the file picker. 2. View the geometry: Points, lines, and polygons render to scale in an SVG preview with the bounding box reported. 3. Inspect attributes: The dBASE attribute table appears below the map so you can read each feature's fields. FAQ: Q: Which files do I need to drop? A: A shapefile is several files that share a name. This viewer reads the .shp file for geometry and the .dbf file for the attribute table. Select both together; the .prj and .shx files are not required for a quick preview. Q: What geometry types are supported? A: It parses the standard ESRI shape types: Point, MultiPoint, PolyLine, and Polygon, including their Z and M variants (the X and Y coordinates are read). Each record's geometry is drawn to scale in the preview. Q: How is the attribute table read? A: The .dbf is a dBASE table with a fixed-width binary header followed by fixed-length records. The tool reads the field definitions and decodes each record as Latin-1 text, skipping rows flagged as deleted, then shows the first 50 rows. Q: Is my data uploaded to a server? A: No. Both files are read with the browser FileReader and parsed with a JavaScript implementation of the shapefile and dBASE formats. Nothing is transmitted, so confidential GIS data stays on your machine. Q: Why are the coordinates not on a real map? A: The preview projects raw coordinates into a scaled drawing without a basemap, so it works offline and for any coordinate system. To overlay on a real map, convert to GeoJSON with our shapefile-to-geojson tool and load it into a map viewer. #### Subresource Integrity (SRI) Hash Generator URL: https://geratools.com/sri-hash-generator Paste file contents or drop a file and compute SHA-256, SHA-384, and SHA-512 hashes with the Web Crypto API, producing the correctly formatted integrity attribute for script and link tags. Subresource Integrity stops a compromised CDN from serving a tampered script, with no server-side build step. Everything runs in your browser. How to use: 1. Provide the file: Paste the exact contents of the JS or CSS file, or drag and drop the file onto the drop zone. The bytes must match what the CDN serves. 2. Pick a hash algorithm: Choose SHA-384 (the common default) or SHA-256/SHA-512. The tool computes the base64 digest with the Web Crypto API. 3. Copy the integrity attribute: Copy the generated integrity value and add it, with crossorigin=anonymous, to your script or link tag. FAQ: Q: What is Subresource Integrity? A: SRI lets the browser verify that a file fetched from a CDN matches a hash you embedded in the tag. If a compromised or malicious CDN alters the file by even one byte, the hash mismatches and the browser refuses to run it. Q: Which algorithm should I use? A: SHA-384 is the widely used default and the one most CDNs publish. SHA-256 and SHA-512 are also valid SRI algorithms. You can even list multiple integrity values separated by spaces and the browser uses the strongest it supports. Q: Why do I also need crossorigin=anonymous? A: For cross-origin resources the browser only enforces integrity when the request is made in CORS mode. Adding crossorigin=anonymous tells it to fetch without credentials in CORS mode so the SRI check can run. Q: Does the hash have to match the served bytes exactly? A: Yes. SRI hashes the raw response body byte-for-byte. If the CDN minifies, re-compresses content differently, or adds a BOM, the hash changes. Generate the hash from the exact file the CDN will serve, and pin a specific version URL. Q: Is my file uploaded to compute the hash? A: No. Hashing uses the browser's Web Crypto API (crypto.subtle.digest) entirely on your device. The file contents never leave your browser. #### Unicode \u Escape Encoder & Decoder URL: https://geratools.com/unicode-escape Free Unicode escape tool — convert characters to JavaScript and Java style \uXXXX escapes (with surrogate pairs) or Python and C style \UXXXXXXXX, and decode them back. Runs in your browser. How to use: 1. Choose encode or decode: Pick whether to turn characters into escape sequences or convert existing escapes back into text. 2. Pick an encoding style: When encoding, choose \uXXXX with surrogate pairs, \UXXXXXXXX for astral characters, or escape every character. 3. Copy the result: The output updates instantly. Click Copy to use it in your source code or data file. FAQ: Q: What is a \uXXXX escape? A: It is a way to write a Unicode character using its code point in hexadecimal. \u00E9 represents the letter e with an acute accent, and \u03A9 represents the Greek capital omega. JavaScript, Java and JSON all use this form. Q: How are emoji and other astral characters handled? A: Characters above U+FFFF need either two \uXXXX escapes forming a UTF-16 surrogate pair, or a single \UXXXXXXXX escape. This tool offers both styles, and the decoder reassembles surrogate pairs automatically. Q: What is the difference between the encoding styles? A: The \uXXXX style matches JavaScript and Java and uses surrogate pairs for emoji. The \UXXXXXXXX style matches Python and C. Escape every character forces all text into escapes, which is handy for fully ASCII-safe output. Q: Can it decode mixed text and escapes? A: Yes. The decoder leaves ordinary characters untouched and only converts valid \uXXXX and \UXXXXXXXX sequences, so you can paste a mostly normal string that contains a few escapes. Q: Is my text uploaded? A: No. The conversion runs entirely in your browser with JavaScript and nothing is sent to a server. #### URL-Safe Base64 Encoder/Decoder URL: https://geratools.com/url-safe-base64 Free URL-safe Base64 encoder and decoder per RFC 4648 §5. Replaces + with - and / with _, optionally drops = padding, and decodes both standard and URL-safe input. Safe for URLs, JWTs, query strings and file names. Client-side. How to use: 1. Choose encode or decode: Pick encode to convert text into URL-safe Base64, or decode to turn URL-safe Base64 back into text. 2. Decide on padding: When encoding, leave padding off for the most compact URL-friendly output, or tick the box to keep the trailing = characters. 3. Copy the result: The converted value appears below with a copy button so you can drop it straight into a URL, token or file name. FAQ: Q: How does URL-safe Base64 differ from standard Base64? A: The encoded data is identical except for two characters. Standard Base64 uses + and /, both of which have special meaning in URLs and file paths. URL-safe Base64 (RFC 4648 §5, also called base64url) substitutes - for + and _ for /, so the string needs no percent-encoding. Q: Why is padding often removed? A: The trailing = characters are only there to make the length a multiple of four. In URLs an = can be ambiguous or need escaping, so base64url commonly drops it. The length still implies how many bytes the final group holds, so a correct decoder recovers the data without padding. Q: Is this the encoding used by JWTs? A: Yes. JSON Web Tokens encode their header, payload and signature with base64url and no padding, joined by dots. You can paste a single JWT segment here to decode it, or encode a JSON payload into the base64url form a JWT expects. Q: Will it decode standard Base64 too? A: Yes. The decoder normalizes - back to + and _ back to /, strips whitespace, and tolerates missing or present padding, so it accepts both the standard and URL-safe alphabets without you choosing which one you have. Q: Does my data leave the browser? A: No. Encoding and decoding, including UTF-8 handling, run entirely in your browser. Nothing is uploaded. #### Bulk UUID / ULID Generator URL: https://geratools.com/uuid-bulk-generator Free bulk UUID v4 and ULID generator. Create up to 100,000 RFC 4122 UUIDs or sortable ULIDs in your browser using crypto.randomUUID(), then copy or download as CSV or TXT. No server, nothing uploaded. How to use: 1. Choose the ID type: Pick UUID v4 for purely random identifiers or ULID for lexicographically sortable, time-prefixed IDs. 2. Set the count: Enter how many values you need, up to 100,000, then press Generate. 3. Export the results: Copy all values to your clipboard, or download them as a CSV or line-separated TXT file. FAQ: Q: What is the difference between UUID v4 and ULID? A: UUID v4 is 128 bits of randomness formatted as 36 characters, with no inherent order. ULID is 26 Crockford base32 characters where the first 10 encode a millisecond timestamp, so ULIDs sort chronologically while staying globally unique. Q: Are these UUIDs cryptographically random? A: Yes. The generator uses crypto.randomUUID() where available and otherwise crypto.getRandomValues(), both backed by the platform's cryptographically secure random number generator. Q: Is anything sent to a server? A: No. Every value is generated locally in your browser. Nothing about your IDs is uploaded, logged, or stored anywhere. Q: Can I generate a really large batch? A: You can generate up to 100,000 IDs at once. Only the first 200 are shown in the preview for performance, but the full set is included in any copy or download. Q: Why are my ULIDs nearly identical at the start? A: The first 10 characters of a ULID encode the current millisecond timestamp, so IDs created in the same millisecond share that prefix. The trailing 16 characters are random and keep each value unique. #### Base64 Encoder URL: https://geratools.com/base64-encoder Free Base64 encoder that turns any UTF-8 text into Base64, with an optional URL-safe variant. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your text: Type or paste the text you want to encode into the input box. 2. Choose URL-safe if needed: Tick the URL-safe option to swap + / for - _ and drop padding for use in URLs. 3. Copy the Base64: The Base64 string updates instantly — click Copy to grab it. FAQ: Q: Does this support Unicode and emoji? A: Yes. Input is encoded as UTF-8 bytes first, so accented characters, non-Latin scripts and emoji all encode correctly. This avoids the classic "Invalid character" error you get from calling btoa directly on non-Latin text. Q: What is URL-safe Base64? A: It replaces + with - and / with _ and removes trailing = padding, so the result can be placed in URLs and filenames without further escaping. It is defined in RFC 4648 and used by JWTs and many APIs. Q: Is my text uploaded anywhere? A: No. Encoding runs entirely in your browser using built-in APIs — nothing is sent to any server. Q: Is Base64 encryption? A: No. Base64 is encoding, not encryption — it has no key and anyone can decode it instantly. It exists to represent binary or text safely in systems that only accept ASCII, such as email, data URIs and JSON. Never use it to hide secrets. Q: Why is Base64 output longer than the input? A: Base64 represents every 3 bytes of input as 4 ASCII characters, so the output is about 33% larger than the original. Padding with = makes the length a multiple of 4 in the standard variant. Q: When should I use standard vs URL-safe Base64? A: Use standard Base64 for email attachments, data URIs and most file encoding. Use URL-safe Base64 when the value goes into a URL path, query string, filename, or a JWT segment, where + / and = would otherwise need percent-escaping. Q: How do I decode Base64 back to text? A: Use the matching Base64 decoder, which reverses the process: it Base64-decodes to bytes and reads them back as UTF-8 text. #### Base64 Decoder URL: https://geratools.com/base64-decoder Free Base64 decoder that converts standard or URL-safe Base64 back into readable UTF-8 text, restoring missing padding automatically. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your Base64: Paste the Base64 string into the input box — standard or URL-safe both work. 2. Read the decoded text: The decoded UTF-8 text appears instantly below the input. 3. Copy the result: Click Copy to grab the decoded text. FAQ: Q: How do I decode a Base64 string? A: Paste it into the box and the decoded UTF-8 text appears instantly. The tool maps each group of 4 Base64 characters back to 3 bytes and decodes them as text. Q: Does it handle URL-safe Base64? A: Yes. The decoder accepts both the standard +/ alphabet and the URL-safe -_ alphabet, converting - to + and _ to / before decoding. Q: What if my Base64 is missing its = padding? A: The decoder restores padding automatically based on the string length, so unpadded Base64 (common in JWTs and URLs) still decodes correctly. Q: Why do I get an invalid input error? A: The string contains characters that are not valid Base64, or its length leaves a single leftover character that cannot form a byte. Stray spaces, truncation, or non-Base64 text are the usual causes. Invalid UTF-8 byte sequences are also flagged. Q: Can it decode Base64 that is not text, like an image? A: This tool decodes the bytes and shows them as UTF-8 text, so binary payloads such as images will not be readable here. For images, use a Base64-to-image tool instead. Q: Is my data uploaded? A: No. Decoding runs entirely in your browser with built-in APIs — nothing is transmitted anywhere. #### SHA-256 Hash Generator URL: https://geratools.com/sha256-hash-generator Free SHA-256 hash generator that turns any text into a 64-character hexadecimal digest using the browser's built-in Web Crypto API. Runs entirely in your browser — nothing is uploaded to any server. How to use: 1. Enter your text: Type or paste the text you want to hash into the input box. 2. Read the SHA-256 digest: The 64-character hexadecimal SHA-256 hash appears instantly below as you type. 3. Copy the result: Click Copy to put the hash on your clipboard. FAQ: Q: Is my text sent to a server? A: No. The hash is computed locally using your browser's built-in Web Crypto API (crypto.subtle.digest). Your text never leaves your device and nothing is uploaded. Q: Is SHA-256 secure? A: Yes. SHA-256 is part of the SHA-2 family and is widely considered secure. It is used in TLS certificates, Bitcoin, file integrity verification, and digital signatures. For password storage, use a dedicated password hash such as bcrypt or Argon2 instead of a raw SHA-256. Q: How long is a SHA-256 hash? A: A SHA-256 hash is 256 bits, shown as 64 hexadecimal characters. The length is always 64 hex characters regardless of how long or short the input is. Q: Is SHA-256 reversible? A: No. SHA-256 is a one-way function — you cannot recover the input from the hash. The only way to "reverse" it is to guess inputs and hash them until one matches, which is why it is used for integrity checks and fingerprints. Q: Will the same text always give the same hash? A: Yes. SHA-256 is deterministic: identical input always yields identical output. Even a one-character change produces a completely different hash, which is what makes it useful for detecting tampering. Q: What is SHA-256 used for? A: It verifies file integrity (checksums), signs TLS certificates, secures the Bitcoin and other blockchains, and acts as a building block in HMAC and digital signatures. It confirms that data has not changed. #### Color Shades & Tints Generator URL: https://geratools.com/color-shades-generator Free colour shades and tints generator. Enter any hex colour and instantly get lighter tints, darker shades and a full 50–900 tonal scale for design systems. Privacy-first — all colours are computed in your browser and nothing is uploaded. How to use: 1. Enter a base colour: Use the colour picker or type a 3- or 6-digit hex code into the field. 2. Read the ramps: The tool shows tints (mixed toward white), shades (mixed toward black) and a 50–900 tonal scale built by sweeping HSL lightness. 3. Copy any swatch: Click a swatch to copy its hex code straight to your clipboard. FAQ: Q: How are the shades calculated? A: Tints linearly interpolate each RGB channel toward white and shades toward black. The 50–900 tonal scale keeps the original hue and saturation while sweeping HSL lightness, which is how design-system colour ramps are built. Q: Are my colours uploaded anywhere? A: No. Every tint, shade and tonal step is computed locally in your browser with JavaScript. Nothing about your colour is sent to a server. Q: What is the difference between a tint, a shade and a tone? A: A tint is the base colour mixed toward white (lighter), a shade is mixed toward black (darker), and the 50–900 tonal scale sweeps lightness in HSL while preserving hue and saturation — the format design systems use. Q: Are the generated hex values accurate? A: Yes. The conversions use standard sRGB and HSL maths, so the hex output is deterministic and matches what your design tool will render. #### Tailwind Shade Generator URL: https://geratools.com/tailwind-shade-generator Generate a full Tailwind CSS 50 to 950 colour ramp from a single base colour and copy a paste-ready theme.extend.colors config. Runs entirely in your browser — nothing is uploaded. How to use: 1. Set your base colour: Pick the colour that should sit around the 500 stop. 2. Name the colour: Type the key name you want in your Tailwind config, for example brand. 3. Copy the config: Click Copy config and paste the block into theme.extend.colors. FAQ: Q: Which Tailwind stops does it generate? A: It generates the standard eleven stops — 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 and 950 — by holding hue and saturation and sweeping lightness. Q: Will it match Tailwind's built-in palettes exactly? A: No. The lightness steps approximate Tailwind's default ramp so any base colour looks balanced, but it is generated from your colour rather than copied from a named palette. Q: Is my colour uploaded anywhere? A: No. The whole ramp is computed locally in your browser and nothing leaves your device. Q: How are the lighter and darker shades calculated? A: The tool converts your base colour to HSL, then keeps its hue and saturation fixed while replacing the lightness with a fixed target per stop — roughly 97% at 50, 56% at 500 and 18% at 950. This keeps every shade in the same colour family. Q: Where do I paste the generated config? A: Drop the block inside theme.extend.colors in your tailwind.config.js or tailwind.config.ts. After that you can use classes like bg-brand-500, text-brand-700 and border-brand-200. Q: My brand colour does not land on the 500 stop — why? A: Each stop has a fixed target lightness, so the tool rebuilds your colour at the 500 lightness (around 56%) rather than placing your exact hex there. If your base is much lighter or darker, the closest match may be a different stop; adjust the base until 500 looks right. Q: Does it support Tailwind v3 and v4? A: Yes. The output is a plain object of hex values under a colour name, which works in the theme.extend.colors block of both Tailwind v3 (JS/TS config) and v4 setups that still use a config file. #### Color From Text Hash URL: https://geratools.com/color-from-text-hash Free color-from-text generator that hashes any string into a consistent HEX, RGB and HSL color. Same text always gives the same color — perfect for avatars, tags and chips. Runs entirely in your browser. How to use: 1. Enter your text: Type any name, tag, username or string into the input field. 2. See the color: A consistent color is derived from a hash of the text and previewed instantly, with readable label text. 3. Copy the values: Copy the HEX, RGB or HSL value to drop the color into your design or code. FAQ: Q: Will the same text always give the same color? A: Yes. The color is derived deterministically from an FNV-1a hash of the text, so identical input always produces identical HEX, RGB and HSL values — ideal for avatars and category chips. Q: How is the color kept readable? A: The generator constrains saturation and lightness to pleasant ranges and picks black or white label text based on relative luminance for good contrast. Q: Will different text usually give different colors? A: Usually, yes. The hue is the hash modulo 360, so similar strings can land on the same hue occasionally, but across a normal set of usernames or tags the colors are well spread out. Q: What output formats does it give? A: It returns the same color as HEX, RGB and HSL, plus a preview swatch. It also picks black or white as a readable label color based on the swatch's luminance. Q: Is my text sent to a server? A: No. The hashing and color math run entirely in your browser. Nothing you type is uploaded or stored. #### ASCII85 Encoder URL: https://geratools.com/ascii85-encoder Free ASCII85 encoder and decoder. Converts text to and from the Adobe ASCII85 format used in PostScript and PDF, with <~ ~> delimiters and z shorthand for zero groups. Runs entirely in your browser. How to use: 1. Pick a direction: Choose Encode to turn text into ASCII85, or Decode to turn an ASCII85 string back into text. 2. Enter your input: Paste the text, or an ASCII85 string (with or without the <~ ~> delimiters), into the input box. 3. Copy the output: The converted result appears below ready to copy. FAQ: Q: How does ASCII85 differ from Z85? A: Both pack four bytes into five characters, but Adobe ASCII85 uses the character range ! to u, wraps output in <~ and ~> delimiters, and uses z as shorthand for an all-zero group. It is the variant found in PostScript and PDF. Q: Can I decode ASCII85 without the delimiters? A: Yes. The decoder accepts input with or without the leading <~ and trailing ~>, and ignores whitespace between characters. Q: Why is ASCII85 more efficient than Base64? A: ASCII85 packs 4 bytes into 5 characters, a 25% size overhead, whereas Base64 packs 3 bytes into 4 characters, a 33% overhead. So ASCII85 produces noticeably smaller output for binary data carried as text. Q: What does the z character mean in ASCII85? A: A single z is shorthand for a group of four zero bytes, which would otherwise encode as the five characters !!!!!. This compression makes runs of zeros much shorter. Q: Is anything uploaded? A: No. ASCII85 encoding and decoding run entirely in your browser; your data stays on your device. #### Base58 Encoder / Decoder URL: https://geratools.com/base58-encoder-decoder Free Base58 and Base58Check encoder and decoder. Convert text or hex to Bitcoin/IPFS-style Base58, verify checksums, and inspect raw bytes. 100% client-side — nothing is uploaded. How to use: 1. Pick encode or decode: Choose whether you are turning data into Base58 or reading a Base58 string back into bytes. 2. Choose your input format: When encoding, switch between UTF-8 text and raw hex bytes so addresses and keys round-trip exactly. 3. Toggle Base58Check if you need a checksum: Enable Base58Check to append or verify the 4-byte double-SHA-256 checksum used by Bitcoin addresses and WIF keys. FAQ: Q: What is Base58 and why does Bitcoin use it? A: Base58 is a binary-to-text encoding that uses 58 characters — the digits and letters minus the four that look alike (zero, capital O, capital I and lowercase l) plus the plus and slash that Base64 uses. Bitcoin adopted it so addresses and keys can be copied, typed and read aloud with far less chance of a transcription error. Q: What is the difference between Base58 and Base58Check? A: Plain Base58 just re-encodes the bytes. Base58Check first appends a 4-byte checksum (the first four bytes of a double SHA-256 of the payload) before encoding. On decode the checksum is recomputed and compared, so a single mistyped character is caught instead of silently producing the wrong address. Q: How does Base58 handle leading zero bytes? A: Because Base58 treats the input as one big number, leading zero bytes would otherwise vanish. The standard fixes this by emitting one leading "1" character (value 0 in the alphabet) for every leading 0x00 byte, then encoding the remaining big integer. This decoder reverses that exactly so byte-for-byte round-trips hold. Q: Can I encode raw hex instead of text? A: Yes. Switch the input format to "Hex bytes" when encoding. This is what you want for public-key hashes, private keys or any binary payload, since typing them as text would corrupt the bytes. Spaces and an optional 0x prefix are ignored. Q: Why does my decoded Base58 show as hex instead of text? A: Many Base58 strings (like addresses) are not UTF-8 text — they are raw bytes. When the bytes are not valid UTF-8 the tool shows the exact byte sequence as hex so you can still inspect or copy it without garbled characters. Q: Is my data sent anywhere? A: No. All encoding, decoding and SHA-256 checksum work happens locally in your browser using the built-in Web Crypto API. No keys, addresses or text ever leave your device. ### Color #### Discord Color Text Generator URL: https://geratools.com/discord-text-formatter A free Discord colour text generator. Pick a text colour, background and bold or underline, and copy a ready-made ANSI code block that renders in colour inside Discord. Everything runs in your browser — no bot, no login. How to use: 1. Type your text: Enter the message you want to colour. Keep it short — colour formatting is best for highlights, headers and warnings. 2. Pick colours and style: Choose a text colour and an optional background, then toggle bold or underline. The live preview shows roughly how it will look in Discord. 3. Copy the code block: Press Copy code block and paste the whole thing — including the triple-backtick ansi lines — straight into a Discord message. FAQ: Q: How do you make coloured text in Discord? A: Discord renders colour inside a code block that starts with three backticks followed by the word ansi. Inside it you use ANSI escape codes to set the colour. This tool builds that block for you so you only have to copy and paste — no need to type escape characters by hand. Q: Why is my coloured text not showing colour? A: Three common reasons: you are on the Discord mobile app, which currently shows ansi blocks without colour; you removed part of the code block when copying, so paste the entire thing including the ```ansi line and the closing ```; or you edited the text and broke the escape codes — regenerate and copy fresh. Q: Which colours does Discord support? A: Discord's ansi support covers a fixed palette of eight text colours (gray, red, green, yellow, blue, pink, cyan, white) and several background shades. This tool only offers colours Discord can actually render, so what you copy is what you get. Q: Does coloured text work on the Discord mobile app? A: Not reliably yet. ANSI colour renders on the Discord desktop apps and the web client. On mobile the same message usually appears as plain monospaced text, so use colour for emphasis rather than essential meaning. Q: Is this safe — do I need a bot? A: No bot and no login needed. The formatter runs entirely in your browser and just produces text you paste yourself. Nothing is sent to a server. #### ANSI Color Code Converter URL: https://geratools.com/ansi-color-code-converter Free ANSI color code converter. Enter a hex color and get the closest ANSI 256-color terminal code, with ready-to-use foreground and background escape sequences. Searches the full palette — 16 system colors, the 6×6×6 cube and the grayscale ramp — by RGB distance. Runs entirely in your browser. How to use: 1. Enter a hex color: Type or paste a hex color using 3 or 6 hex digits, with or without the leading hash. 2. Read the nearest code: The converter shows the closest ANSI 256 code, a swatch comparison, and whether it is an exact match. 3. Copy the escape sequence: Copy the raw foreground escape sequence or the plain code to use in your scripts and terminal output. FAQ: Q: What is the ANSI 256-color palette? A: It is the standard extended color set most terminals support. Codes 0 to 15 are the system and bright colors, codes 16 to 231 form a 6×6×6 RGB cube, and codes 232 to 255 are a 24-step grayscale ramp. Together they give 256 selectable colors. Q: How does the tool find the nearest color? A: It computes the exact RGB value of all 256 palette entries, then measures the squared Euclidean distance from your hex color to each one and returns the entry with the smallest distance. If the distance is zero, your color is an exact palette match. Q: How do I use the resulting code in a terminal? A: Wrap the code in an escape sequence. For text color use ESC[38;5;Nm and for background use ESC[48;5;Nm, where N is the code. Reset afterwards with ESC[0m. The ESC character is the literal escape byte, often written \e or \033. Q: How are the cube colors calculated? A: For codes 16 to 231 the index minus 16 splits into red, green and blue levels of 0 to 5. Each non-zero level maps to the value 55 plus 40 times the level, while level 0 maps to 0. That non-linear step is why the cube is not a simple even spread. Q: Why is my color only approximate? A: The 256-color palette is a fixed grid, so most arbitrary hex colors fall between palette points. The converter returns the perceptually nearest available code, but for true color you can use a terminal that supports 24-bit ANSI with the ESC[38;2;R;G;Bm sequence instead. #### ANSI Color Codes URL: https://geratools.com/ansi-color-codes Reference for 3/4-bit, 8-bit and 24-bit ANSI terminal color codes with a rendered preview. Copy SGR foreground and background sequences for the 16-color, 256-color and truecolor palettes. How to use: 1. Pick a palette: Choose 3/4-bit, 8-bit or use the truecolor sliders to target your terminal's capability. 2. Preview and copy: See each color's swatch and click Copy to grab its SGR sequence with a real ESC byte. 3. Build truecolor: Enter red, green and blue values to generate a 24-bit ESC[38;2;r;g;bm sequence. FAQ: Q: What is the difference between 16, 256 and truecolor ANSI? A: 16-color (3/4-bit) uses codes 30-37, 90-97 for foreground; 256-color (8-bit) uses ESC[38;5;n m with n from 0-255; and truecolor (24-bit) uses ESC[38;2;r;g;b m for any sRGB color. Support depends on the terminal. Q: How do I set the background instead of the foreground? A: Swap the leading code: foreground uses 30-37 or 38, while background uses 40-47 or 48. For example ESC[41m is a red background and ESC[31m is red text. Q: Why should I always reset with ESC[0m? A: SGR attributes persist until changed, so without a reset every following line keeps the same color or style. Ending colored output with ESC[0m restores the terminal's default appearance. Q: How is the 256-color palette laid out? A: Indices 0-15 are the standard and bright colors, 16-231 form a 6x6x6 RGB cube, and 232-255 are a 24-step grayscale ramp. The tool computes each index's approximate color the same way. Q: Will truecolor work in my terminal? A: Most modern terminals (recent xterm, iTerm2, Windows Terminal, GNOME Terminal) support 24-bit truecolor, but some older or restricted environments only handle 256 or 16 colors. Test with a small sample before relying on it. #### Base16 (Hex) Encoder/Decoder URL: https://geratools.com/base16-encode Free Base16 encoder and decoder following RFC 4648 — turn text into uppercase hexadecimal byte pairs and back again. UTF-8 aware, with validation for odd lengths and bad characters, all in your browser. How to use: 1. Pick encode or decode: Choose whether to turn text into hex pairs or convert hex back into text. 2. Enter your data: For encoding, type any text. For decoding, paste hex pairs — spaces between them are optional. 3. Read and copy the result: The output updates instantly. Click Copy to grab it. Decoding shows a clear error for odd lengths or bad characters. FAQ: Q: What is Base16 per RFC 4648? A: Base16 is the standard hexadecimal encoding defined in RFC 4648. Each byte is represented by exactly two characters drawn from 0–9 and A–F, using uppercase letters in the canonical form. Q: Why is the output uppercase? A: RFC 4648 specifies the uppercase alphabet 0–9 and A–F for Base16. Lowercase hex is widely accepted on input, so this tool decodes both cases but always emits uppercase to match the standard. Q: How is text turned into bytes? A: The text is first encoded as UTF-8, which produces the actual bytes. Those bytes are then written as hex pairs. ASCII characters use one byte each, while accented letters and emoji use two to four bytes. Q: What if my hex has an odd number of digits? A: Each byte needs exactly two hex digits, so the total count must be even. If it is odd, the tool reports an error instead of guessing, because the data would be ambiguous. Q: Does it validate the input when decoding? A: Yes. It ignores whitespace, rejects any character outside 0–9 and A–F, requires an even digit count, and confirms the resulting bytes are valid UTF-8 — reporting a specific error for each failure. #### Color Mix Calculator URL: https://geratools.com/color-mix-calculator Mix two colors at any ratio and get the exact resulting RGB and hex value. Computes both a gamma-correct (physically accurate) blend and a simple linear blend, with a live preview of the result. How to use: 1. Enter two colors: Type each color as a hex code (#ff0000) or as comma-separated RGB values (255,0,0). 2. Choose the mix ratio: Drag the slider to set what percentage of color B goes into the blend; the rest is color A. 3. Read and copy the result: See the gamma-correct mixed color with a live swatch, then click to copy its hex value. FAQ: Q: What is the difference between the gamma-correct and linear mix? A: The gamma-correct mix converts colors to linear light, averages, then converts back, which matches how light physically blends. The simple linear mix averages the raw sRGB values and can look muddy for vivid colors. Q: Which result should I use? A: For most realistic blending, especially mixing bright colors, use the gamma-correct result. The simple linear result is shown for comparison and matches what naive RGB averaging produces. Q: What input formats does it accept? A: Each color can be a 3- or 6-digit hex code with or without a leading hash, or three comma- or space-separated numbers from 0 to 255. Invalid input is reported rather than guessed. Q: What does a 50 percent mix mean? A: At 50% the blend uses equal parts of both colors. Moving the slider toward 100% weights the result toward color B, and toward 0% weights it toward color A. Q: Is the output an exact value? A: Yes. Each channel is computed and rounded to the nearest integer, then shown as both an rgb() triple and a hex code so you can paste it directly into CSS or a design tool. #### Color Opacity / Alpha Mixer URL: https://geratools.com/color-opacity-mixer Free color opacity mixer — blend a semi-transparent foreground color at any alpha over a chosen background and get the exact opaque hex result. See the alpha-blending formula applied live with a preview swatch. How to use: 1. Set the foreground color and alpha: Choose the overlay color and an opacity from 0 to 100 percent. 2. Set the background color: Pick the background it sits on — typically white or black, but any hex works. 3. Read the flattened result: The tool shows the resulting opaque hex, which is what the eye actually sees. FAQ: Q: How does alpha blending work? A: Each channel is mixed with the standard source-over formula: result = foreground * alpha + background * (1 - alpha). Alpha runs from 0 (fully transparent) to 1 (fully opaque), and the same formula applies to red, green, and blue independently. Q: Why does the same color look different on white versus black? A: A semi-transparent color lets the background show through. Over white the blend lifts toward white; over black it darkens. The flattened hex captures the actual visible color for the background you chose. Q: What is a flattened or composited color? A: It is the single opaque color that looks identical to the transparent overlay sitting on its background. Designers flatten colors to define solid tokens, borders, or states that must match a layered preview. Q: Does alpha of 50 percent give the exact midpoint? A: Yes. At alpha 0.5 each channel is the simple average of the foreground and background channel values, because both weights are 0.5. Q: Is my color data uploaded? A: No. The blend is plain arithmetic that runs entirely in your browser. Nothing leaves your device. #### Color Temperature to RGB Converter URL: https://geratools.com/color-temperature-to-rgb Convert a blackbody color temperature from 1000K to 40000K into approximate sRGB and hex, with a live swatch and presets for candlelight, daylight, and blue sky. Useful for lighting, white-balance, and shader work. Runs in your browser. How to use: 1. Set the temperature: Type a Kelvin value from 1000 to 40000 or drag the slider to sweep from warm candlelight up through cool blue sky. 2. Read the RGB: The tool returns approximate sRGB and hex values and updates the live swatch so you can see the warm-to-cool shift instantly. 3. Use a preset: Tap a preset such as Incandescent or D65 to jump to a common lighting temperature and read its color straight away. FAQ: Q: What is blackbody color temperature? A: It is the temperature, in Kelvin, of an idealized glowing object whose emitted light matches a given color. Low temperatures near 2000K glow orange like a candle, while high temperatures near 10000K appear cool and blue, the opposite of everyday warm and cool language. Q: How accurate is this conversion? A: It uses Tanner Helland's well-known polynomial approximation, which tracks the Planckian locus closely enough for UI, lighting design, and shader work. It is an approximation, not a spectrally exact computation, and is most accurate in the 1000K to 40000K range. Q: Why do higher temperatures look blue, not red? A: Physically hotter blackbodies emit more energy at shorter, bluer wavelengths. The familiar warm and cool labels in photography are reversed from the physics, so 2700K bulbs are called warm white even though they are physically cooler than 6500K daylight. Q: What temperature is neutral white? A: Around 6500K, the D65 daylight standard, which is the white point sRGB and most monitors are calibrated to. It converts to a near-equal RGB value. Common warm-white indoor bulbs sit near 2700K to 3000K. Q: Can I convert RGB back to a temperature? A: Not uniquely, because most RGB colors do not lie exactly on the blackbody curve. You can only find a correlated color temperature, the nearest point on the locus. This tool runs the conversion in one direction, from Kelvin to RGB. #### National Flag Colours Reference URL: https://geratools.com/country-flag-colors-reference Searchable reference of national flag colours, layout, and symbolism by country, with hex colour swatches, the flag design pattern, and the year the current flag was adopted. How to use: 1. Search a country: Type a country name or a colour to filter the flag list. 2. View the colours: See the hex colour swatches that make up the flag plus its layout pattern. 3. Read the meaning: Check the short note on the design and what the colours symbolise. FAQ: Q: Are these the exact official flag colours? A: The hex values are close, widely used web approximations of each flag's colours. Official specifications often use Pantone or textile colour standards, so for print or manufacturing always check the country's official flag specification. Q: What does the layout field describe? A: Layout describes the basic geometric design, such as horizontal tricolour, vertical tricolour, a cross, or a field with a canton. It is a quick way to group flags by their visual structure. Q: Why do so many flags use red, white, and blue? A: Red, white, and blue spread widely through revolutionary and colonial history, notably from the French and American flags, and through pan-Slavic colours. They are bold, high-contrast, and easy to reproduce, which is why they recur so often. Q: What are pan-African and pan-Arab colours? A: Pan-African colours are red, gold, green, and sometimes black, drawn from the Ethiopian flag and the early independence movements. Pan-Arab colours are red, white, black, and green. Many flags adopted them to signal regional solidarity. Q: Does the adopted year mean the country is that old? A: No. The adopted year is when the current flag design took its present form, which is often much later than independence. Countries frequently revise their flag after constitutional changes, so a recent year does not mean a new nation. #### Windows-1252 Hex Dump URL: https://geratools.com/cp1252-encode Map input text through the Windows-1252 (CP1252) encoding table and output the hex bytes, including the 0x80 to 0x9F range that holds the euro sign, curly quotes, and em dash. Explains why CP1252 read as Latin-1 causes mojibake. Runs in your browser. How to use: 1. Paste your text: Enter the text you want to inspect, including any smart quotes, dashes, or the euro sign. 2. Read the hex bytes: The tool outputs the Windows-1252 byte for each character and a per-character dump. 3. Copy the byte string: Copy the space-separated hex bytes for use in debugging encoding issues or building data files. FAQ: Q: How does Windows-1252 differ from ISO-8859-1? A: They are identical for byte values 0x00 to 0x7F and 0xA0 to 0xFF. The difference is the 0x80 to 0x9F range, which Latin-1 leaves as control codes but Windows-1252 fills with printable characters like the euro sign, em dash, and curly quotes. Q: Why does my text turn into mojibake? A: If text was saved as Windows-1252 but read as ISO-8859-1 or UTF-8, the 0x80 to 0x9F bytes are misinterpreted. A curly quote becomes a stray symbol or a question-mark box. Knowing the actual CP1252 bytes helps you diagnose and fix the mismatch. Q: What does a dash in the output mean? A: A dash means the character has no Windows-1252 byte. CP1252 is a single-byte encoding covering only 256 values, so characters like emoji or most non-Western scripts cannot be represented and are flagged rather than guessed. Q: Is Windows-1252 the same as ANSI? A: In Microsoft software, ANSI usually refers to the active code page, which on Western Windows installations is Windows-1252. The term ANSI is misleading, but in practice it most often means CP1252 in English-language environments. Q: When should I still care about CP1252? A: Plenty of legacy files, exports, and Windows applications still emit CP1252. When you import that data into a UTF-8 world you must know it is CP1252 to decode it correctly, which is what this dump helps you confirm. #### CSS Named Colors URL: https://geratools.com/css-named-colors Searchable CSS color-name reference. Every CSS Color Level 4 named color with its hex code, computed RGB and HSL values, a live swatch and one-click copy. Search by name or hex. How to use: 1. Search a color: Type a color name or hex value to filter the list down to matching swatches. 2. Read the values: Each row shows hex, RGB and HSL computed from the same color so you can pick your preferred format. 3. Copy the hex: Click Copy hex to put the color value on your clipboard for use in your stylesheet. FAQ: Q: How many named colors does CSS support? A: CSS Color Module Level 4 defines 148 named colors. A handful are spelling aliases that share a hex value, such as gray/grey and aqua/cyan, so the number of distinct colors is slightly lower. Q: Are CSS named colors reliable across browsers? A: Yes. The named color keywords are standardised with exact sRGB hex values, so the same name renders identically in every modern browser. They are a safe shortcut for common colors. Q: How are the RGB and HSL values calculated? A: The tool parses each color's canonical hex value into red, green and blue bytes, then converts those to HSL using the standard hue/saturation/lightness formula. Every format describes the exact same color. Q: What is rebeccapurple? A: rebeccapurple (#663399) was added to the CSS spec in memory of Eric Meyer's daughter Rebecca. It is a fully standard named color you can use like any other. Q: Should I use named colors in production CSS? A: Named colors are convenient for prototypes and common shades, but design systems usually prefer hex or custom properties for precise brand colors. The hex shown here is exactly what each keyword resolves to. #### Hex Dump Viewer URL: https://geratools.com/hex-dump-viewer Free in-browser hex dump viewer. Drop any file and read a classic address, hex bytes and ASCII sidebar layout with configurable bytes per row and pagination. No upload — files are read locally with FileReader. How to use: 1. Choose a file: Select any file from your device. It is read in your browser with the FileReader API and never uploaded. 2. Set bytes per row: Pick 8, 16, 24 or 32 bytes per row to match the layout you prefer for reading the dump. 3. Read the dump: Each line shows the offset, the hex byte values and an ASCII sidebar; large files page automatically. FAQ: Q: What is a hex dump? A: A hex dump is a textual view of a file's raw bytes. Each line typically shows the byte offset, the bytes as two-digit hexadecimal, and an ASCII sidebar so you can spot text, headers and structure inside binary data. Q: Which bytes show as readable characters? A: Printable ASCII bytes in the range 0x20 to 0x7e are shown as their character and highlighted. Every other byte, including control characters and high bytes, is shown as a dot in the ASCII column. Q: Is there a file size limit? A: To stay responsive in the browser the viewer caps files at 16 MB and pages the output 4 KB at a time. For larger files, slice them first or use a desktop hex editor. Q: Is my file uploaded to a server? A: No. The file is read locally using the browser FileReader API, so its contents never leave your device. That makes it safe for inspecting sensitive or proprietary files. Q: What is the offset column for? A: The offset is the position of the first byte on that row, in hexadecimal. It lets you reference a specific byte by address, which is essential when following a file-format spec or a struct layout. #### Hexspeak Word Encoder URL: https://geratools.com/hexspeak Free hexspeak encoder — turn words into hexadecimal-readable strings like DEADBEEF and CAFEBABE, with live hex-validity and decimal-value checks. Runs in your browser. How to use: 1. Type your words: Enter one or more words you want to turn into hexspeak. 2. Read the encoded output: Each word is substituted with hex-lookalike digits, and the tool shows whether the result is valid hexadecimal. 3. Copy the result: Click Copy to grab the hexspeak string for use as a magic number or label. FAQ: Q: What is hexspeak? A: Hexspeak is the practice of spelling words using only the sixteen hexadecimal digits 0 to 9 and A to F, optionally swapping some letters for lookalike digits. Famous examples include DEADBEEF and CAFEBABE, which programmers use as recognisable magic numbers in memory. Q: Which letters can be encoded? A: The letters a to f are already hex digits, so they stay. Others are mapped to lookalike digits: i and l become 1, o becomes 0, s becomes 5, t becomes 7, z becomes 2, and g becomes 6. Q: What if a word contains a letter with no hex equivalent? A: Letters such as h, j, k, m, n, p, q, r, u, v, w, x and y have no hexadecimal lookalike. They are kept visible but the tool flags the word as not valid hex and lists which letters could not be mapped. Q: Why does it show a decimal value? A: When a word encodes to valid hexadecimal, the tool interprets it as a number and shows its base-ten value. This is how DEADBEEF becomes the constant 3735928559 used in real software. Q: Is my text uploaded anywhere? A: No. The encoding runs entirely in your browser, so nothing is sent to a server. #### KML Color / Style Editor URL: https://geratools.com/kml-style-editor Free KML style editor — parses Style and StyleMap elements from a KML file and lets you visually change line color, polygon fill color, line width, and icon scale, then export the updated KML. No Google Earth needed; runs client-side. How to use: 1. Paste your KML: Drop the KML text containing your Style blocks into the input box. 2. Edit each style: Use the color pickers, opacity sliders, width, and scale fields to adjust every parsed style. 3. Export the KML: The updated KML rebuilds instantly. Copy it back into your file or upload to Google Earth. FAQ: Q: Why are KML colors in a strange order? A: KML stores color as an 8-digit hex string in aabbggrr order — alpha, blue, green, red — which is the reverse of the rrggbb web format. This tool converts between the two automatically so you can use a normal color picker. Q: What does the opacity value control? A: The first two hex digits (alpha) set transparency, from 00 (fully transparent) to ff (fully opaque). The editor exposes this as a 0–100% slider and writes the correct two-digit hex back into the color. Q: Which style properties can I edit? A: It edits LineStyle color and width, PolyStyle color (fill), and IconStyle scale and color. Other elements in the file are preserved unchanged so your placemarks and geometry are not affected. Q: Does it work with StyleMap? A: StyleMap elements that reference shared Style blocks by id are preserved, and editing the underlying Style updates both the normal and highlight states that point to it. Inline styles inside placemarks are also detected. Q: Is my KML uploaded? A: No. Parsing and rebuilding the KML happen entirely in your browser using the built-in XML parser, so your map data never leaves your device. #### CIE L*a*b* to RGB Color Converter URL: https://geratools.com/lab-to-rgb Free CIELAB to RGB converter. Enter L*, a*, and b* values under the D65 white point and get the equivalent sRGB color, hex code, and swatch, with an out-of-gamut warning. Runs entirely in your browser. How to use: 1. Enter L*, a*, and b*: Type the lightness (0-100), green-red (a*), and blue-yellow (b*) values. 2. Read the sRGB result: The equivalent RGB triplet and hex code update instantly, with a live swatch. 3. Copy the result: Click Copy to put the hex or rgb() value on your clipboard. FAQ: Q: How does Lab convert back to RGB? A: The Lab values are run through the inverse CIELAB function to recover XYZ relative to the D65 white, multiplied by the XYZ-to-linear-sRGB matrix, then gamma-encoded and scaled to 0-255 to produce the displayable RGB color. Q: What does out of gamut mean? A: Lab can describe colors that no sRGB monitor can show. When the computed RGB falls outside 0-255, the value is clamped into range and the tool flags it, because the on-screen color is only an approximation of the requested Lab color. Q: What white point is assumed? A: The D65 illuminant, matching sRGB and CSS lab(), with reference white Xn=95.047, Yn=100, Zn=108.883. Using a different white point would shift the resulting RGB. Q: What are the valid ranges? A: L* runs from 0 (black) to 100 (white). a* and b* are unbounded in theory but typically fall between about -128 and 127 for real colors; values beyond the sRGB gamut will be clamped. Q: Is anything sent to a server? A: No. The inverse matrix and gamma math run entirely in your browser. Nothing is uploaded or logged. #### Oklch to RGB Converter URL: https://geratools.com/oklch-to-rgb Free Oklch to RGB converter — turn Oklch lightness, chroma, and hue values into sRGB hex and rgb() using the correct Oklab matrix and cube-root math, with a live preview and out-of-gamut warning. How to use: 1. Enter Oklch values: Set lightness L (0–1), chroma C (typically 0–0.4), and hue H in degrees (0–360). 2. Read the sRGB result: The tool converts Oklch through Oklab to linear sRGB and outputs hex and rgb() values. 3. Check the gamut warning: If the color falls outside sRGB it is flagged; the displayed hex is the clamped, in-gamut approximation. FAQ: Q: How does Oklch convert to RGB? A: Oklch is the polar form of Oklab: a = C·cos(H) and b = C·sin(H), with L unchanged. The Oklab values are converted to nonlinear LMS by an inverse matrix, cubed to linear LMS, mapped to linear sRGB by a second matrix, then gamma-encoded to sRGB and scaled to 0–255. Q: What is Oklab and why is it used? A: Oklab is a perceptual color space designed so that equal numeric steps look like equal perceptual steps, and so that lightness, chroma, and hue change independently. That makes Oklch ideal for generating smooth gradients and consistent palettes. Q: What does the out-of-gamut warning mean? A: Oklch can describe colors more saturated than an sRGB screen can show. When a value lies outside the sRGB gamut, the converter clamps each channel into range and warns you, because the displayed color is then only an approximation. Q: What is a typical chroma range? A: Chroma in Oklch usually runs from 0 (grey) up to roughly 0.37 for the most saturated sRGB colors. Values much above that for a given lightness and hue will be out of gamut. Q: Is my data uploaded? A: No. Every conversion runs entirely in your browser using local matrix math. Nothing is sent to a server. #### Pantone PMS Color Reference URL: https://geratools.com/pantone-color-reference Browse and search a reference table of popular Pantone PMS spot colors with their approximate sRGB and hex equivalents. Copy hex codes for screen mockups and design work. Runs entirely in your browser. How to use: 1. Search for a color: Type a PMS number or color name into the search box to filter the swatch list instantly. 2. Inspect the swatch: Each row shows the approximate sRGB swatch, the hex code, and the RGB triplet for that Pantone color. 3. Copy the hex: Click the copy button to put the hex value on your clipboard for use in a design tool or CSS. FAQ: Q: Are Pantone hex values exact? A: No. Pantone colors are physical spot inks mixed for print, and there is no exact, lossless mapping to sRGB. The hex values here are widely used approximations for on-screen previews and should never replace a printed Pantone swatch book for production. Q: Why does my print look different from the hex on screen? A: Screens emit RGB light while Pantone inks reflect light on paper, so the gamuts differ. Paper stock, ink batch, and lighting all shift the result. Use these hex codes for digital mockups only and confirm with a physical Pantone guide for press work. Q: What is the difference between coated and uncoated Pantone colors? A: The same PMS ink looks different on coated (C) glossy stock versus uncoated (U) absorbent stock. Coated appears brighter and more saturated. This reference lists generalized coated approximations; check the specific C or U value for your job. Q: Can I use these colors commercially? A: The hex approximations themselves are just color values and free to use. Pantone numbers and the official color libraries are Pantone's intellectual property; you typically need a licensed Pantone product for production color matching. Q: Does this cover every Pantone color? A: No. The Pantone Matching System has thousands of colors. This is a curated reference of commonly used PMS spot colors. For a complete, color-accurate set you need an official Pantone fan deck or licensed digital library. #### Pantone to RGB Approximator URL: https://geratools.com/pantone-to-rgb Look up approximate sRGB and hex values for common Pantone spot colors, including the Color of the Year list and popular PMS swatches. Search by Pantone number or name and copy the screen approximation. Runs in your browser. How to use: 1. Search a Pantone color: Type a Pantone number such as 19-4052 or a name like Classic Blue to filter the list. 2. Read the approximation: Each match shows an approximate hex code, the RGB triplet, and a swatch. 3. Copy the value: Click copy to put the hex approximation on your clipboard for screen use. FAQ: Q: Why are these only approximations? A: Pantone spot colors are mixed inks defined for print, not screen. There is no exact, lossless mapping to sRGB because the gamuts differ. These values are widely used screen approximations and will look close but not identical to a printed swatch. Q: Should I use these for production print work? A: No. For print, specify the Pantone number directly to your printer and proof against a physical Pantone guide. Use these RGB values only for on-screen mockups, web previews, and digital comps. Q: Which Pantone colors are included? A: The table covers the Pantone Color of the Year series and a selection of widely referenced PMS spot colors. It is a curated lookup, not the full Pantone library of several thousand inks. Q: What is the difference between a coated and uncoated Pantone color? A: The C and U suffixes mean the ink is printed on coated or uncoated paper, which changes how it looks. These approximations target the coated appearance, which is the most commonly quoted. Q: Can I convert RGB back to a Pantone number here? A: This tool goes Pantone to RGB only. Reverse matching needs a nearest-color search against a licensed Pantone database and a calibrated environment, which is beyond a screen approximation. #### RAL Color to Hex Converter URL: https://geratools.com/ral-to-hex Convert RAL Classic paint and coatings codes to approximate hex and RGB screen values. Search by RAL number or name across the full RAL Classic range and copy the closest digital match. Runs in your browser. How to use: 1. Search a RAL code: Type a RAL Classic number like 5010 or a name such as Traffic White to filter the list. 2. Read the conversion: Each match shows an approximate hex code, the RGB triplet, and a swatch of the color. 3. Copy the value: Click copy to put the hex value on your clipboard for use in design tools or CSS. FAQ: Q: What is RAL Classic? A: RAL Classic is the European color-matching standard widely used for paints, coatings, and powder finishes. Each color has a four-digit code where the first digit groups the hue, for example 1 for yellows, 5 for blues, and 9 for whites, greys, and blacks. Q: Are these hex values exact? A: No. RAL is a physical coatings standard, so converting to sRGB is an approximation. Screens and paint have different gamuts and finishes change appearance. Use these for digital previews, not for color-critical specification. Q: How should I specify RAL for real paint? A: Quote the RAL number directly to your supplier and confirm against a physical RAL fan deck or sample. Gloss level and substrate change how the same RAL code looks in reality. Q: What does a code like RAL 9005 mean? A: The leading 9 places it in the white/black/grey group, and the full code identifies the specific shade. RAL 9005 is Jet Black, one of the most commonly specified RAL colors. Q: Is RAL the same as Pantone? A: No. RAL is mainly a coatings standard common in Europe, while Pantone is an ink-mixing system common in print and branding. They are separate libraries with no exact cross-mapping. #### RGB to CMYK Color Converter URL: https://geratools.com/rgb-to-cmyk Free RGB to CMYK converter. Enter red, green, and blue values (0-255) and get the equivalent Cyan, Magenta, Yellow, and Key/Black percentages for print, with a live swatch. Runs entirely in your browser. How to use: 1. Enter R, G, and B: Type each channel value from 0 to 255 into the three boxes. 2. Read the CMYK values: The cyan, magenta, yellow, and key (black) percentages update instantly. 3. Copy the result: Click Copy to put the CMYK string on your clipboard for your print workflow. FAQ: Q: How does RGB convert to CMYK? A: Each RGB channel is normalised to 0-1. The key (black) is one minus the largest channel. Cyan, magenta, and yellow are then derived from the remaining brightness in each channel after removing the black component. Q: Is this conversion exact for printing? A: No. This is the standard arithmetic conversion with no ICC color profile. Real presses use device profiles and ink behaviour, so treat these values as a close starting point rather than a final print spec. Q: What does the K in CMYK stand for? A: K stands for Key, the black plate. Black gets its own ink rather than mixing C, M, and Y because pure black is sharper, cheaper, and avoids the muddy brown that mixed inks produce. Q: What CMYK does pure black give? A: Pure RGB black (0,0,0) converts to 0% C, 0% M, 0% Y, and 100% K. The formula puts all the darkness into the black plate rather than mixing colored inks. Q: Is anything sent to a server? A: No. The conversion runs entirely in your browser using the standard formula. Nothing is uploaded or logged. #### RGB to Grayscale Converter URL: https://geratools.com/rgb-to-grayscale Convert any RGB or hex color to its perceptual grayscale value using the ITU-R BT.601 luminance formula. See the gray hex and rgb() output, a BT.709 comparison, and side-by-side swatches. How to use: 1. Enter a color: Type a hex code like 2. Read the grayscale value: The BT.601 luminance formula returns a single gray level, shown as hex and rgb() with a preview swatch. 3. Copy the grayscale color: Click to copy the resulting gray hex, ready to use in CSS or a design tool. FAQ: Q: Why not just average the three channels? A: The human eye is far more sensitive to green than to red or blue. A plain average treats them equally and looks wrong; weighting by perceived brightness gives a gray that matches how light or dark the color actually appears. Q: What formula does this tool use? A: It uses the ITU-R BT.601 luma formula: gray = 0.299 x R + 0.587 x G + 0.114 x B. The result is the same value placed in all three channels to produce a neutral gray. Q: What is the BT.709 number shown below? A: BT.709 is the luma weighting used for HD video and sRGB displays: 0.2126 x R + 0.7152 x G + 0.0722 x B. It is shown for comparison; it weights green even more heavily than BT.601. Q: Does this account for sRGB gamma? A: No. Like most image-editing grayscale conversions, this applies the luma weights directly to the gamma-encoded sRGB values. A fully gamma-correct relative-luminance conversion would linearize first and is used mainly for contrast-ratio math. Q: What input formats are accepted? A: You can enter a 3- or 6-digit hex code with or without a hash, or three comma- or space-separated numbers from 0 to 255. Invalid input is reported clearly. #### RGB to CIE L*a*b* Color Converter URL: https://geratools.com/rgb-to-lab Free RGB to CIELAB converter. Convert sRGB colors through linear RGB and XYZ to CIE L*a*b* values under the D65 illuminant, with a live swatch. Accurate gamma and matrix math, all in your browser. How to use: 1. Enter R, G, and B: Type each channel value from 0 to 255 into the three boxes. 2. Read the L*a*b* values: Lightness (L*), green-red (a*), and blue-yellow (b*) update instantly. 3. Copy the result: Click Copy to put the lab() string on your clipboard. FAQ: Q: What is CIELAB? A: CIE L*a*b* is a device-independent, perceptually uniform color space. L* is lightness (0 black to 100 white), a* runs green to red, and b* runs blue to yellow. Equal distances in Lab roughly match equal perceived color differences. Q: How is the conversion done? A: sRGB is gamma-expanded to linear RGB, multiplied by the sRGB-to-XYZ matrix under the D65 white point, then XYZ is normalised to that white and passed through the CIELAB cube-root function to give L*, a*, and b*. Q: Why convert through XYZ? A: CIELAB is defined relative to CIE XYZ tristimulus values, not RGB. You cannot go straight from RGB to Lab, so the color must first be linearised and transformed into XYZ using the correct matrix and white point. Q: What white point does this use? A: It uses the D65 illuminant, the standard daylight white point for sRGB, with reference white Xn=95.047, Yn=100, Zn=108.883. This matches CSS lab() and most design tools. Q: Is anything uploaded? A: No. All gamma, matrix, and cube-root math runs locally in your browser. Nothing about your colors leaves your device. #### RGB to LCH Color Converter URL: https://geratools.com/rgb-to-lch Free RGB to LCH converter. Convert sRGB colors to the CIELCh model (the cylindrical form of CIELAB) with lightness, chroma, and hue angle, plus a live swatch. Accurate D65 math, all in your browser. How to use: 1. Enter R, G, and B: Type each channel value from 0 to 255 into the three boxes. 2. Read the LCH values: Lightness (L), chroma (C), and hue angle (H in degrees) update instantly. 3. Copy the result: Click Copy to put the lch() string on your clipboard. FAQ: Q: What is CIELCh? A: CIELCh is the cylindrical form of CIELAB. Instead of the rectangular a* and b* axes, it uses chroma (distance from the gray axis, i.e. colorfulness) and hue (an angle around the color wheel), which are more intuitive to adjust. Q: How is it computed from RGB? A: RGB is converted to CIELAB first (gamma expand, sRGB-to-XYZ under D65, then the CIELAB function). Chroma is the hypotenuse of a* and b*, and hue is the arctangent of b* over a*, normalised to 0-360 degrees. Q: How does LCH differ from HSL? A: HSL is a simple transform of RGB and is not perceptually uniform, so equal hue steps can look uneven. LCH is built on CIELAB, so its lightness and chroma track human perception far more closely, which is why it is preferred for accessible palettes. Q: What is the hue angle? A: Hue is measured in degrees from 0 to 360. Roughly, 0 is reddish-magenta, 90 is yellow, 180 is cyan-green, and 270 is blue. Grays have no defined hue because their chroma is zero. Q: Is anything uploaded? A: No. The full RGB to Lab to LCH pipeline runs in your browser. Nothing about your colors leaves your device. #### RGB to Oklab Color Converter URL: https://geratools.com/rgb-to-oklab Convert any sRGB or hex color to Oklab, the modern perceptually-uniform color space built for smooth gradients and predictable lightness. Also outputs CSS oklab() and oklch(). Runs entirely in your browser. How to use: 1. Enter your color: Pick a color with the swatch, paste a hex code, or type R, G, and B values from 0 to 255. 2. Read the Oklab values: The tool shows L (lightness), a (green to red), and b (blue to yellow), plus ready-to-paste CSS oklab() and oklch() strings. 3. Copy and use: Copy the oklab() value and drop it straight into your stylesheet for gradients and color steps that look even to the human eye. FAQ: Q: What is the Oklab color space? A: Oklab is a perceptually uniform color space published by Björn Ottosson in 2020. Equal numeric steps look like equal visual steps, which makes it ideal for gradients, color mixing, and lightness adjustments. It is supported natively in CSS via the oklab() and oklch() functions. Q: How is sRGB converted to Oklab? A: First each channel is linearized from gamma-encoded sRGB. The linear RGB is multiplied by a matrix into an LMS-like cone response, each component is passed through a cube root, then a second matrix produces the final L, a, and b values. Q: What is the difference between oklab() and oklch()? A: They describe the same space. oklab() uses Cartesian a and b axes, while oklch() uses polar chroma and hue. oklch() is usually easier to author by hand because changing hue or saturation maps to a single intuitive number. Q: What range do the L, a, and b values use? A: L runs from 0 (black) to 1 (white). The a and b axes are unbounded in theory but for in-gamut sRGB colors they typically stay within roughly minus 0.4 to plus 0.4. CSS expresses L as a percentage from 0% to 100%. Q: Why use Oklab instead of HSL for gradients? A: HSL gradients often pass through muddy or overly dark midpoints because HSL lightness is not perceptual. Oklab keeps perceived lightness consistent across the blend, so a gradient from blue to yellow stays vivid instead of dipping to grey. #### RGB to Oklch Color Converter URL: https://geratools.com/rgb-to-oklch Free RGB to Oklch converter. Convert sRGB colors to Oklch (Oklab in cylindrical form) with lightness, chroma, and hue, plus a live swatch. Uses Bjorn Ottosson's exact Oklab matrices, all in your browser. How to use: 1. Enter R, G, and B: Type each channel value from 0 to 255 into the three boxes. 2. Read the Oklch values: Lightness (0-1), chroma, and hue angle (degrees) update instantly. 3. Copy the result: Click Copy to put the oklch() string on your clipboard for modern CSS. FAQ: Q: What is Oklch? A: Oklch is the cylindrical form of the Oklab color space. It expresses a color as lightness, chroma (colorfulness), and hue angle, but on top of Oklab, which is engineered to be highly perceptually uniform and to keep hue stable when lightness changes. Q: How is it computed from RGB? A: sRGB is gamma-expanded to linear RGB, transformed to the LMS cone space with Oklab's first matrix, each LMS value is cube-rooted, then the second matrix produces Oklab L, a, b. Chroma and hue are the polar form of a and b. Q: Why use Oklch instead of LCH? A: Oklch fixes hue-shift problems that affect CIELAB-based LCH, especially for blues, and keeps perceived lightness more consistent. It is the recommended perceptual space in modern CSS Color 4 and design tools. Q: What are the value ranges? A: Lightness runs from 0 (black) to 1 (white). Chroma starts at 0 (gray) and is open-ended but is usually below about 0.4 for sRGB colors. Hue is an angle from 0 to 360 degrees. Q: Is anything uploaded? A: No. The full RGB to Oklab to Oklch pipeline runs locally in your browser using exact matrices. Nothing about your colors leaves your device. #### sRGB to Display P3 Converter URL: https://geratools.com/rgb-to-p3 Free sRGB to Display P3 converter — turn any hex or sRGB color into the CSS color(display-p3 ...) value using the correct linearization and matrix math, so colors match on wide-gamut screens. How to use: 1. Enter an sRGB color: Type a hex color such as 2. Read the Display P3 value: The tool outputs a ready-to-paste CSS color(display-p3 r g b) string with components from 0 to 1. 3. Use it in CSS: Drop the value into a color property; wide-gamut screens render the same color, others fall back automatically. FAQ: Q: How is sRGB converted to Display P3? A: The sRGB channels are first linearized by undoing the sRGB transfer curve. Those linear values are multiplied by an sRGB-to-XYZ matrix, then by an XYZ-to-linear-P3 matrix. Finally the P3 transfer curve (the same gamma as sRGB) is reapplied to get encoded P3 components. Q: Will the converted color look different? A: For colors that exist in sRGB, the P3 value is computed to look the same on a calibrated wide-gamut screen — that is the whole point. Display P3 simply gives access to more saturated colors that sRGB cannot reach at all. Q: Why are P3 components written from 0 to 1? A: The CSS color(display-p3 r g b) function expects floating-point components in the 0–1 range rather than 0–255 integers. This tool outputs that format directly so it is ready to paste into a stylesheet. Q: Do sRGB and Display P3 share the same gamma curve? A: Yes. Display P3 uses the same transfer function (gamma) as sRGB; only the primaries and white-point handling differ. That is why the conversion is mainly a linear matrix transform between linear-light spaces. Q: Is my color data uploaded anywhere? A: No. All matrix math runs entirely in your browser and nothing is sent to a server. #### RGB to CIE XYZ Color Converter URL: https://geratools.com/rgb-to-xyz Convert sRGB or hex colors to CIE XYZ tristimulus values under the D65 illuminant, including chromaticity coordinates. The foundation for Lab, Luv, and device-independent color work. Runs in your browser. How to use: 1. Enter your color: Pick a color with the swatch, paste a hex code, or type R, G, and B values from 0 to 255. 2. Read the XYZ values: The tool linearizes the sRGB channels and applies the standard D65 matrix to output X, Y, and Z scaled to a reference white of 100. 3. Use the chromaticity: The x and y chromaticity coordinates below describe the color's hue and saturation independent of brightness, ready for CIE diagrams. FAQ: Q: What are CIE XYZ tristimulus values? A: CIE XYZ is a device-independent color space defined by the CIE in 1931 that models human color perception. X, Y, and Z are tristimulus values, with Y representing luminance. Almost every other perceptual space, including Lab, Luv, and Oklab, is derived from XYZ. Q: Why is the sRGB linearized first? A: sRGB values are gamma-encoded so that bits are allocated efficiently for human vision. The XYZ matrix expects linear-light values, so each channel must first be inverse-gamma-corrected before the matrix multiplication. Skipping this step gives wrong results. Q: What does the D65 illuminant mean? A: D65 is a standard daylight white point with a correlated color temperature near 6500K. sRGB is defined relative to D65, so this converter uses the D65 RGB-to-XYZ matrix. Using a different white point would shift every output value. Q: What scale are X, Y, and Z on? A: Here they are scaled so the reference white has Y equal to 100, the most common convention for Lab conversions. Some tools instead use a 0 to 1 range; just divide each value by 100 to switch between the two. Q: What are the x and y chromaticity coordinates? A: Lowercase x and y are normalized values computed as X over (X+Y+Z) and Y over (X+Y+Z). They pin down the color's chromaticity on the CIE 1931 diagram independent of how bright it is, which is useful for comparing displays and light sources. #### Tailwind Color Config Generator URL: https://geratools.com/tailwind-color-config-generator Generates a complete Tailwind CSS color scale of 50 to 950 shades from a single base color, anchored at step 500. Outputs a ready-to-paste tailwind.config.js color object. Runs in your browser. How to use: 1. Pick a base color: Use the color picker or type a hex value. This color becomes the 500 step of the scale. 2. Name the color key: Enter the name Tailwind will use, such as brand or accent, which becomes the object key in your config. 3. Copy the config: Review the live swatch ramp, then copy the generated tailwind.config.js colors object straight into your project. FAQ: Q: Which step does my base color become? A: Your chosen color is anchored at step 500, the middle of the scale. Lighter steps (50 to 400) and darker steps (600 to 950) are generated around it by adjusting lightness while preserving your hue. Q: How are the lighter and darker shades calculated? A: The base color is converted to HSL. Each step keeps the hue and maps to a fixed target lightness ramp from 97 percent at step 50 down to 13 percent at step 950. Saturation is nudged slightly up for dark steps and down for light steps for a natural feel. Q: Where do I paste the output? A: Put the generated object inside theme.extend.colors in your tailwind.config.js. You can then use utility classes like bg-brand-500 or text-brand-200 anywhere in your markup. Q: Why use a full 50 to 950 scale instead of one color? A: A full scale gives you consistent hover, border, background, and text variants of the same hue. It is the convention Tailwind's own palette follows, so your custom color behaves like the built-in ones. Q: Does it accept short hex codes? A: Yes. Both 3-digit codes like #39f and 6-digit codes like #3b82f6 are accepted. Three-digit values are expanded to six internally before the scale is built. #### CIE XYZ to RGB Color Converter URL: https://geratools.com/xyz-to-rgb Convert CIE XYZ tristimulus values under the D65 illuminant back to sRGB and hex, with a gamut warning when the result falls outside the sRGB triangle. The inverse of the RGB-to-XYZ transform. Runs in your browser. How to use: 1. Enter XYZ values: Type the X, Y, and Z tristimulus values on the reference-white-equals-100 scale used by most Lab tools. 2. Read the sRGB output: The tool applies the inverse D65 matrix, re-applies the sRGB gamma curve, and shows the resulting rgb() and hex color with a live swatch. 3. Check the gamut warning: If any channel falls outside 0 to 255 the color is outside the sRGB gamut, so it is clamped and flagged as out of gamut. FAQ: Q: How is XYZ converted back to sRGB? A: The X, Y, Z values are divided by 100, multiplied by the inverse sRGB-to-XYZ matrix to get linear RGB, then each channel is gamma-encoded with the sRGB transfer function and scaled to 0 to 255. This is the exact reverse of the forward transform. Q: What does out of gamut mean? A: The sRGB gamut covers only a triangle of all visible colors. Some valid XYZ values map to negative or greater-than-one linear RGB, meaning no sRGB display can show them. This tool clamps such channels to the 0 to 255 range and warns you. Q: What white point does this use? A: It uses D65, the daylight white point with a color temperature near 6500K that sRGB is defined against. The inverse matrix is the D65 sRGB matrix, so your XYZ values should also be relative to a D65 reference white for accurate results. Q: What scale should my XYZ values be on? A: This tool expects the reference white to have Y equal to 100, matching the common Lab convention. If your XYZ values are on a 0 to 1 scale, multiply each by 100 before entering them, or your output will be far too dark. Q: Why does pure XYZ white not give pure RGB white? A: It does, when you use the D65 white values X equals 95.05, Y equals 100, Z equals 108.88. If you enter equal X, Y, Z values you get a slightly tinted near-white because those are not the D65 white point coordinates. #### CSS Mesh Gradient Generator URL: https://geratools.com/css-mesh-gradient Free CSS mesh gradient generator. Place 3 to 6 colour points, drag their positions, randomize palettes, and copy a pure-CSS background made of layered radial gradients — no images required. Live preview runs in your browser. How to use: 1. Adjust the colour points: Pick a colour for each point and drag its X and Y sliders to position it across the canvas. 2. Add or randomize: Add up to six points, or hit Randomize to generate a fresh palette and layout instantly. 3. Copy the CSS: Copy the generated background-color and layered background-image declaration into your stylesheet. FAQ: Q: What is a mesh gradient in CSS? A: A mesh gradient is the smooth blending of several colour points across a surface. In CSS it is approximated by stacking multiple radial gradients — one per colour point — over a solid base colour, which is exactly what this tool generates. Q: Does the output use any images? A: No. The result is 100 percent CSS: a background-color plus a background-image made of layered radial-gradient() functions. There are no image files, so it scales crisply to any size and adds no extra network requests. Q: How many colour points should I use? A: Three to four points usually give a rich, balanced blend. More than that can look busy. The tool caps the count at six to keep the CSS manageable and the render fast. Q: Will this work in all browsers? A: Layered radial gradients are supported in every modern browser. The output uses only standard CSS gradient syntax, so no vendor prefixes are required for current browsers. #### Hex Colour Opacity Converter URL: https://geratools.com/hex-opacity Free hex opacity converter. Enter a hex colour and an opacity percentage to get the 8-digit #RRGGBBAA hex, the matching rgba() string, and the alpha byte on its own. Paste an 8-digit hex to read its opacity back. Runs in your browser. How to use: 1. Enter a hex colour: Type or pick a base 2. Set the opacity: Drag the opacity slider from 0 to 100 percent. The checkerboard swatch shows the true transparency. 3. Copy the result: Copy the 8-digit hex, the rgba() string, or just the two-character alpha byte. FAQ: Q: What is an 8-digit hex colour? A: It is a hex colour with two extra characters for the alpha channel: #RRGGBBAA. The last pair encodes opacity from 00 (fully transparent) to FF (fully opaque). It is supported in all modern browsers and is the hex equivalent of an rgba() colour. Q: How is the alpha byte calculated from a percentage? A: The opacity percentage is multiplied by 255 and rounded, then written as a two-character hex value. For example 50 percent is 0.5 × 255 ≈ 128, which is 80 in hex, giving an alpha of 80. Q: When should I use #RRGGBBAA vs rgba()? A: They are equivalent. Use 8-digit hex when your design tokens or variables are already hex-based; use rgba() when you prefer decimal channels or need to compute the colour in JavaScript. This tool gives you both. Q: Can I go the other way? A: Yes. Paste an 8-digit hex and the tool reads its opacity back onto the slider and shows the equivalent rgba() and alpha byte. #### Hex to Text Converter URL: https://geratools.com/hex-to-text-converter Free hex to text converter that turns hexadecimal byte sequences into readable UTF-8 text and back again. Accepts 0x, spaces and separators. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a direction: Pick Hex to Text to decode bytes, or Text to Hex to encode. 2. Paste your input: Enter your hex bytes or text. Hex input may include 0x prefixes, spaces, colons or commas. 3. Copy the result: The converted output appears instantly — click Copy to grab it. FAQ: Q: What hex formats are accepted? A: Hex input can include 0x prefixes and be separated by spaces, colons, semicolons or commas. The converter strips those and reads the remaining digits as pairs (one byte each). Q: Does it support Unicode? A: Yes. Bytes are decoded as UTF-8 and text is encoded as UTF-8, so accented characters, non-Latin scripts and emoji all convert correctly. A multi-byte character spans several hex pairs. Q: Why does my hex fail to decode? A: Decoding uses strict UTF-8, so a byte sequence that is not valid UTF-8 is rejected rather than producing garbage. Check that you have an even number of hex digits and that the bytes form a real UTF-8 string. Q: How many hex digits per character? A: Each byte is two hex digits. Plain ASCII letters are one byte (two digits). Accented Latin characters are usually two bytes, and emoji are typically four bytes, so they take four, eight, or more hex digits. Q: Is hex the same as ASCII codes? A: For plain English text, yes — each character maps to its ASCII byte written in hex, e.g. A is 41. But this tool is UTF-8 aware, so it also handles characters beyond ASCII that have no single ASCII code. Q: Is my input uploaded? A: No. Conversion runs entirely in your browser with built-in APIs — nothing is sent to any server. #### Hex to Decimal Converter URL: https://geratools.com/hex-to-decimal Free hex to decimal converter — paste a hexadecimal value (with or without a 0x prefix) and get the base-10 number, plus binary and octal. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter a hex value: Type or paste a hexadecimal value using 0-9 and A-F. A leading 0x prefix and spaces are allowed. 2. Read the decimal value: The base-10 result appears instantly, with the binary and octal forms alongside. FAQ: Q: How does hex to decimal conversion work? A: Each hexadecimal digit is a power of sixteen. The value is the sum of each digit times its place value — for example 0xBEEF is 11x16 cubed + 14x16 squared + 14x16 + 15 = 48879. Q: Can I include a 0x prefix or spaces? A: Yes. A leading 0x (case-insensitive) and any spaces are stripped automatically before conversion, so pasted values just work. Letters A–F may be upper or lower case. Q: What do the hex letters A to F mean? A: Hex needs 16 symbols per digit, so after 0–9 it uses A=10, B=11, C=12, D=13, E=14, F=15. So FF is 15x16 + 15 = 255. Q: Why is hexadecimal used in computing? A: Each hex digit maps to exactly four binary bits, so two hex digits represent one byte cleanly. That makes hex a compact, readable way to write colours (#FF8800), memory addresses, and byte data. Q: What is the largest value I can convert? A: The tool converts up to the JavaScript safe-integer limit (2^53 − 1, i.e. 9007199254740991, or 0x1FFFFFFFFFFFFF). Larger hex values would lose precision, so they are rejected rather than shown wrong. Q: Is my data sent to a server? A: No. The conversion runs entirely in your browser — nothing is uploaded anywhere. #### Hex to RGB Converter URL: https://geratools.com/hex-to-rgb Free hex to RGB converter. Paste a 3- or 6-digit hex colour (or use the picker) and get the rgb() value plus individual R, G and B channels with a live colour swatch. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter your hex code: Type or paste a hex colour such as 2. Read the RGB value: The rgb() string and the individual R, G and B channels update instantly. 3. Copy the result: Click Copy rgb() to put the value on your clipboard for CSS or design tools. FAQ: Q: What hex formats are supported? A: Both 3-digit shorthand (e.g. Q: How do I convert hex to RGB by hand? A: Split the 6-digit hex into three pairs and convert each pair from base 16 to base 10. For example Q: Is my colour data uploaded anywhere? A: No. The conversion runs entirely in your browser using JavaScript — nothing is uploaded or stored on a server. Q: How does 3-digit shorthand expand to 6 digits? A: Each digit is doubled. #fff expands to #ffffff, and #abc expands to #aabbcc. The tool does this automatically before converting, so shorthand and full codes give the same RGB result. Q: What range do the R, G and B channels use? A: Each channel is an 8-bit value from 0 to 255, because each hex pair (00–ff) maps to 0–255. rgb(0, 0, 0) is black and rgb(255, 255, 255) is white. Q: How do I add transparency to an RGB colour? A: Use the rgba() form, which adds an alpha channel from 0 (fully transparent) to 1 (opaque), for example rgba(59, 130, 246, 0.5). This converter outputs the solid rgb() value; append the alpha yourself. Q: Does an invalid hex code do anything? A: If the input is not a valid 3- or 6-digit hex code, the tool shows a short error and waits — it does not guess a colour. Fix the code (e.g. remove stray characters) and the RGB value appears again. #### CSS Gradient Generator URL: https://geratools.com/css-gradient-generator Free CSS gradient generator. Create linear and radial gradients with unlimited colour stops, adjust the angle, see a live preview and copy the ready-to-paste CSS. Privacy-first — everything runs in your browser and nothing is uploaded. How to use: 1. Choose a gradient type: Pick linear or radial. For linear gradients, drag the angle slider to set the direction. 2. Set your colour stops: Edit each stop's colour with the picker or hex field and drag its position slider. Use “Add stop” for more colours. 3. Copy the CSS: The live preview updates as you edit. Click “Copy CSS” to grab the ready-to-paste background declaration. FAQ: Q: What is the difference between a linear and radial gradient? A: A linear gradient blends colours along a straight line at a given angle, while a radial gradient blends outward from a centre point in a circle. This tool supports both. Q: Is my work sent anywhere? A: No. The gradient and CSS are generated entirely in your browser with JavaScript. Nothing about your colours or design is uploaded to any server. Q: Is the generated CSS accurate and standards-compliant? A: Yes. The tool outputs standard linear-gradient() and radial-gradient() syntax supported by all modern browsers. The preview is rendered by your own browser, so it matches exactly what you will get. Q: What does the angle in a linear gradient mean? A: The angle sets the direction of the blend in degrees. 0deg runs bottom to top, 90deg runs left to right, 180deg runs top to bottom and 270deg runs right to left. The tool accepts any value from 0 to 360. Q: How many colour stops can I add? A: As many as you like. The tool starts with two stops and you can add more with the Add stop button; each stop has its own colour and a position from 0% to 100%. Q: Why is my gradient not showing on an element? A: A gradient is an image, not a colour, so it must be set with the background or background-image property, not background-color. Paste the generated background declaration and give the element a defined width and height. Q: Can I use a gradient as text colour? A: Yes. Apply the gradient as a background, then add background-clip: text and color: transparent to the element so the gradient shows through the letters. #### Random Color Palette Generator URL: https://geratools.com/random-color-palette Free random colour palette generator. Create harmonious 5-colour palettes — analogous, monochrome, triadic, complementary or fully random — with one click, then copy the hex codes or CSS variables. Privacy-first, runs entirely in your browser. How to use: 1. Pick a scheme: Choose analogous, monochrome, triadic, complementary or fully random. 2. Generate a palette: Press “Generate” to create a new 5-colour palette. Keep pressing until you find one you like. 3. Copy the colours: Click any swatch to copy its hex, or copy the CSS custom properties block to use the palette in your stylesheet. FAQ: Q: How are the palettes generated? A: Each palette starts from a random base hue (using your browser's secure random generator) and applies a colour-wheel harmony in HSL space — for example analogous rotates the hue by ±30°/±60°, triadic by 120°, and complementary by 180°. Q: Is anything sent to a server? A: No. Palettes are generated entirely in your browser. Nothing about the colours is uploaded anywhere. Q: Are the colours genuinely random and correct? A: Yes. The base hue uses the Web Crypto secure random generator when available, and the harmony offsets use deterministic HSL maths, so the hex values are accurate and the randomness is high quality. Q: What is the difference between analogous and triadic schemes? A: Analogous colours sit next to each other on the colour wheel (hue ±30° and ±60° from the base) for a soft, cohesive look. Triadic colours are spaced 120° apart, giving a vibrant, balanced contrast. Complementary pairs sit 180° opposite for maximum contrast. Q: How do I use the palette in CSS? A: Copy the CSS custom properties block the tool generates — it defines variables like --color-1 through --color-5 with the hex values — then paste it into your stylesheet and reference the variables with var(--color-1). Q: Can I get the same palette twice? A: Each press of Generate picks a new random base hue, so palettes differ every time. There is no fixed seed, so to keep a palette you like, copy its hex codes before generating again. #### CMYK to RGB Converter URL: https://geratools.com/cmyk-to-rgb Free CMYK to RGB converter. Enter cyan, magenta, yellow and key (black) percentages and get the equivalent RGB value with a live swatch. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter C, M, Y and K: Type each ink percentage from 0 to 100 into the four boxes. 2. Read the RGB value: The rgb() string and individual channels update instantly below. 3. Copy the result: Click Copy rgb() to put the value on your clipboard for CSS. FAQ: Q: What is the CMYK to RGB formula? A: Each RGB channel equals 255 times (1 minus the ink) times (1 minus black). For example R = 255 * (1 - C/100) * (1 - K/100). This is the standard naive conversion used when no ICC colour profile is involved. Q: Will the screen colour exactly match my print? A: Not always. CMYK is device and paper dependent and uses ICC profiles for accurate proofing. This tool gives the standard mathematical conversion, which is ideal for web mockups and quick previews. Q: What does the K in CMYK stand for? A: K stands for Key, which is the black ink. It is called the key plate in printing because the other colours are aligned (keyed) to it. A higher K darkens every channel. Q: What RGB is CMYK 0, 100, 100, 0? A: Pure red — rgb(255, 0, 0). With no cyan and no black, and full magenta and yellow, red is at maximum while green and blue drop to zero. Q: Is anything sent to a server? A: No. The conversion runs entirely in your browser — nothing is uploaded or logged. #### Monochrome Palette Generator URL: https://geratools.com/monochrome-palette-generator Generate a monochromatic colour palette from one base colour by holding the hue and varying lightness for a cohesive, clash-free scheme. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a base colour: Pick the hue you want the whole palette built around. 2. Set the swatch count: Choose how many tones you want, from light to dark. 3. Use the swatches: Read the hex of each tone for your light, mid and dark shades. FAQ: Q: What is a monochromatic palette? A: A monochromatic palette keeps a single hue and varies only lightness and saturation. It is the safest scheme to look coordinated because there are no competing colours. Q: How many swatches can I generate? A: You can generate between three and eleven tones, swept evenly from light to dark across the chosen hue. Q: When should I use a monochromatic palette? A: When you want a calm, unified look — dashboards, minimal brands, and single-colour UI states (default, hover, active). It removes the risk of clashing hues entirely. Q: How do I get tints and shades from one colour? A: Keep the hue fixed and raise the lightness for tints (lighter) or lower it for shades (darker), adjusting saturation slightly. This generator does that sweep automatically. Q: What colour format does it output? A: Hex codes (e.g. Q: Is anything uploaded? A: No. The palette is computed locally in your browser and your colour never leaves your device. #### Color Temperature Converter (Kelvin to RGB) URL: https://geratools.com/color-temperature-converter Convert a colour temperature in Kelvin to an approximate sRGB hex and RGB value using the black-body approximation. Free, instant, and runs entirely in your browser — nothing is uploaded. How to use: 1. Set the temperature: Drag the slider or type a value in Kelvin, from warm candlelight (~1900 K) to cool shade (~8000 K). 2. Read the colour: The approximate sRGB hex and RGB values update instantly, with a live preview swatch. 3. Copy the hex: Click the preview swatch to copy the hex code to your clipboard. FAQ: Q: How is the Kelvin-to-RGB colour calculated? A: It uses Tanner Helland's widely-cited black-body radiator approximation, which is accurate enough for white-balance, lighting and LED reference between roughly 1000 K and 40000 K. Q: Is this a precise colorimetric measurement? A: No: it is a visual approximation of how a black-body radiator at that temperature appears on an sRGB screen, not a calibrated colorimetric value. Q: What Kelvin value is warm white versus cool white? A: Warm white is roughly 2700–3000 K (orange-tinted, like a soft incandescent bulb), neutral white is around 4000 K, and cool or daylight white is 5000–6500 K (bluish). Above 6500 K light looks distinctly blue. Q: Why does a higher Kelvin look bluer, not hotter? A: It is counterintuitive, but a hotter black-body radiator emits more blue light. So low Kelvin appears warm/orange and high Kelvin appears cool/blue — the opposite of the everyday "warm/cool" sense of temperature. Q: Is anything sent to a server? A: No — the conversion runs entirely in your browser and nothing is uploaded. #### Hex to Pantone (Approximate) URL: https://geratools.com/hex-to-pantone-approx Find the nearest Pantone PMS coated approximations to any hex colour using a perceptual colour-distance match. A free digital-reference tool that runs entirely in your browser — nothing is uploaded. How to use: 1. Enter a hex colour: Type a hex value or use the colour picker to choose one. 2. Review the matches: The five closest Pantone PMS coated colours appear, ranked by an approximate match percentage. 3. Copy the code: Click a result to copy its Pantone code to your clipboard. FAQ: Q: How is the nearest Pantone found? A: It compares your hex against a curated table of common Pantone PMS coated colours using a perceptual colour-distance metric (a luminance-weighted "redmean" distance) and ranks the closest five matches. Q: Is the match exact? A: No, it is an approximation. Pantone spot inks cannot be reproduced exactly from a screen colour, so treat the result as a starting point, not a guarantee. Q: Why does it show five results instead of one? A: Several Pantone colours often sit close to a given hex, and the "best" one depends on whether you care most about hue, lightness, or saturation. Showing the top five lets you pick the one that matches your intent. Q: What does the match percentage mean? A: It is derived from the colour distance — 100% would be an identical colour, and the percentage falls as the nearest Pantone drifts further from your hex. It is a relative guide, not a print-accuracy figure. Q: Why is a "redmean" distance used instead of plain RGB distance? A: Plain RGB distance treats all channels equally, which does not match how the eye perceives colour. The redmean formula weights red and blue by the average red level, giving results that look closer to human judgement than raw Euclidean RGB. Q: Is my colour sent to a server? A: No — everything is computed in your browser against a built-in table, with no network requests. #### Color Format Converter URL: https://geratools.com/color-format-converter Free live colour format converter. Pick a colour or paste a value and get HEX, RGB(A), HSL(A) and HWB instantly, with an alpha slider, RGB channel sliders, WCAG contrast and one-click copy. 100% in your browser. How to use: 1. Pick or paste a colour: Use the native colour picker, drag the RGB sliders, or paste any value such as #4f46e5, rgb(79 70 229) or hsl(244 76% 59%) into one of the format fields. 2. Set the alpha: Drag the alpha slider to set opacity from 0 to 1. RGBA, HSLA and 8-digit HEX update automatically when alpha is below 1. 3. Copy the format you need: Every format row has its own Copy button. Click it to put HEX, RGB, HSL or HWB on your clipboard, then save the colour as a swatch for later. FAQ: Q: What is the difference between HEX, RGB, HSL and HWB? A: HEX and RGB both describe a colour by its red, green and blue amounts (HEX in hexadecimal, RGB in decimal 0-255). HSL describes it by hue, saturation and lightness, which is friendlier for picking tints and shades. HWB describes it by hue plus how much white and black are mixed in, which many designers find the most intuitive. All four describe the same pixel — this tool just shows every notation at once. Q: How do I add transparency or an alpha channel? A: Drag the alpha slider. When alpha is below 1 the converter switches HEX to its 8-digit form (the last two digits are the alpha byte) and shows rgba() and hsla() instead of rgb() and hsl(). HWB uses the slash syntax hwb(h w% b% / a). Q: Can I paste a colour from my code to convert it? A: Yes. Paste into any of the four format fields. The converter accepts 3-, 4-, 6- and 8-digit HEX, comma or space separated rgb()/rgba(), hsl()/hsla() and modern hwb() syntax, then recalculates every other format from your input. Q: Why does the converted value look slightly different when I round-trip it? A: HSL and HWB use floating-point hue, saturation and lightness, while RGB and HEX are integers from 0 to 255. Converting HSL to RGB and back can shift a value by one unit because of that rounding. The tool keeps RGBA as the source of truth to minimise drift, but tiny differences at the edges are normal and visually identical. Q: What do the contrast ratios mean? A: They show the WCAG contrast ratio of your colour against pure white and pure black. A ratio of 4.5:1 or higher passes AA for normal text, and 3:1 or higher passes AA for large text. Use it as a quick check that text in your chosen colour will be readable. Q: Is my colour data sent anywhere? A: No. All conversion, contrast maths and swatch storage happen entirely in your browser using JavaScript. Saved swatches live in your browser localStorage and never leave your device. Q: Are these the same values my CSS will render? A: Yes for HEX, RGB and HSL, which map directly to CSS colour notations. HWB is also a standard CSS Color 4 function supported by modern browsers. If you target older browsers, prefer the HEX or RGB output, which are universally supported. #### Color Scale Builder URL: https://geratools.com/color-scale-builder Build a perceptually even colour scale from 2-6 anchor colours. Choose OKLab, HSL or sRGB blending, set the number of steps, then export ready-to-use CSS custom properties, JSON design tokens or SVG swatches. 100% in your browser. How to use: 1. Set your anchor colours: Pick 2 to 6 anchor colours with the swatch pickers or by typing hex codes. The raw gradient bar shows how they connect. 2. Choose a blend space and step count: OKLab gives perceptually even steps, HSL travels the hue wheel, sRGB is a plain average. Drag the steps slider to set how many swatches the ramp produces. 3. Export the scale: Copy the generated CSS custom properties, JSON design tokens or hex array, or download an SVG sheet of labelled swatches. FAQ: Q: What does the blend space setting change? A: It controls the maths used to interpolate between your anchor colours. OKLab is a perceptual colour space, so each step looks evenly spaced to the eye and midpoints stay vivid instead of going grey. HSL interpolates hue, saturation and lightness, which sweeps around the colour wheel and is good for rainbow-style ramps. sRGB averages the red, green and blue channels directly — fast, but it often produces a muddy middle. Q: Why use OKLab instead of plain RGB mixing? A: Plain RGB mixing of two saturated colours frequently passes through a dull grey midpoint because perceived lightness is not linear in RGB. OKLab was designed so that equal numeric steps correspond to roughly equal perceived changes, which keeps a scale smooth and the middle swatches saturated. It is the same model behind the CSS oklab() and oklch() functions. Q: How many anchor colours can I use? A: Between two and six. With two anchors you get a straight blend; with more, the scale passes smoothly through each one in order, splitting the total steps evenly across the segments. Use Reverse to flip the direction without re-entering colours. Q: What are the token names like color-50 to color-900? A: The exporter maps each step onto a familiar 50-900 design-token scale (the convention used by Tailwind and many design systems), rounded to the nearest 50. Change the prefix field to rename them, for example brand-50 or accent-500, so the output drops straight into your stylesheet or token file. Q: Can I download the palette as an image? A: Yes. The Download SVG swatches button saves a vector sheet with one rectangle per step, each labelled with its hex value. SVG stays crisp at any size and opens in any browser or design tool, and it is generated entirely on your device. Q: Is anything uploaded or stored online? A: No. Every colour calculation, the OKLab conversions and all exports run locally in your browser using plain JavaScript and the canvas-free maths in this page. Your settings are saved only to this browser's local storage so the tool remembers your last scale, and nothing is sent to any server. #### CSS Color Names URL: https://geratools.com/css-color-names Browse all 140+ named CSS colours with a live swatch, plus hex, rgb and hsl values you can copy with one click. Filter by colour family and search by name or value — runs entirely in your browser. How to use: 1. Search or filter: Type a colour name (tomato), a hex value (#ff6347), or pick a colour family chip to narrow the list. 2. Read the swatch and values: Each card shows the live colour, its hex code, and the equivalent rgb() and hsl() values. 3. Copy what you need: Click any value row to copy the hex, rgb, hsl or the bare name straight to your clipboard. FAQ: Q: How many named colours does CSS have? A: CSS defines 147 distinct named colour keywords (148 names if you count both grey and gray spellings, plus close to 160 once every gray/grey alias is included). They come from the original SVG/X11 palette, with rebeccapurple added in CSS Color Module Level 4. This tool lists the full set with both gray and grey spellings. Q: Are CSS colour names case sensitive? A: No. Colour keywords are case-insensitive, so Tomato, tomato and TOMATO all resolve to the same colour. Most style guides write them lowercase. This tool stores and copies them lowercase to match that convention. Q: What is the difference between gray and grey in CSS? A: Both spellings are valid and identical. CSS accepts gray, grey, lightgray, lightgrey, darkgray, darkgrey, dimgray, dimgrey, slategray and slategrey. Pick one spelling and stay consistent across a codebase so search-and-replace stays reliable. Q: Should I use colour names or hex codes in production CSS? A: Named colours are great for prototypes, demos and readable defaults. For brand-accurate work, hex, rgb or hsl give you exact control and support alpha (rgba / hsla). Many teams define CSS custom properties so the literal value lives in one place regardless of format. Q: How is the colour family filter decided? A: Each colour is converted to HSL in your browser, then bucketed by hue, saturation and lightness — near-grey colours go to the gray or white group, warm low-saturation tones to brown, and the rest by hue angle. It is a practical grouping for browsing, not an official CSS classification. Q: Is transparent a CSS colour name? A: Yes, transparent is a valid colour keyword, but it has no opaque swatch (it is fully see-through) so it is omitted from this visual list. It is equivalent to rgba(0, 0, 0, 0). The currentColor keyword is also special: it resolves to the element's text colour rather than a fixed value. ### CSS & Frontend #### Favicon Generator URL: https://geratools.com/favicon-generator Free favicon generator that creates PNG icons in 8 sizes (16×16 to 512×512) from 1–2 letters. Pick background colour, text colour, and shape (rounded, circle, or square). Runs entirely in your browser — nothing uploaded to any server. How to use: 1. Enter 1 or 2 letters: Type the initials or abbreviation for your site (e.g. "Fa" for a site called Favicon Tools). 2. Pick colours and shape: Choose a background colour, text colour, and icon shape (rounded corners, circle, or square). 3. Download the sizes you need: Click Generate, then download individual PNG files (16 px through 512 px). Add the 32 px as your browser favicon and 180 px as the Apple Touch Icon. FAQ: Q: Which sizes should I download? A: At minimum grab 32×32 (browser tab), 180×180 (Apple Touch Icon for iOS), and 192×192 (Android/PWA). For a full modern set also grab 16×16 and 512×512. Q: Is my design uploaded to a server? A: No — all drawing happens inside your browser using the HTML5 Canvas API. Nothing is sent to any server. Q: Can I use this for a commercial project? A: Yes. The icons you generate are yours to use without restriction. Q: How do I add the favicon to my website? A: Put the PNG files in your site root and add link tags to the page : a 32×32 icon link, a 180×180 apple-touch-icon link, and a 192×192 icon link. The tool prints the exact HTML snippet after you generate. Q: Do I need an .ico file or is PNG enough? A: Modern browsers (Chrome, Edge, Firefox, Safari) all accept PNG favicons via the link tag, so you no longer need a multi-resolution favicon.ico. PNGs are sharper on high-DPI screens. Q: What sizes does it generate? A: Eight square PNGs are produced at once: 16, 32, 48, 64, 128, 180, 192 and 512 pixels. The 180 px is for Apple Touch Icon and 192/512 px cover the PWA web app manifest. Q: Can I use an image or logo instead of letters? A: No — this generator draws 1–2 letters on a coloured shape. It is ideal for quick lettermark icons. If you already have a logo image you want resized into icon sizes, use the image resize tool instead. #### CSS Animation Properties Reference URL: https://geratools.com/css-animation-properties Searchable CSS animation property reference covering animation-name, duration, timing-function, delay, iteration-count, direction, fill-mode, play-state, scroll timelines and @keyframes with values and defaults. How to use: 1. Search the property: Type an animation property name or keyword to filter the reference to matching entries. 2. Check values and defaults: Each entry lists the accepted values and the initial value the property takes when omitted. 3. Compose the shorthand: Use the notes to combine longhands into the animation shorthand, remembering the two-time ordering rule. FAQ: Q: What is the difference between fill-mode forwards and both? A: forwards keeps the styles of the last keyframe after the animation ends. backwards applies the first keyframe's styles during the delay before it starts. both does both at once, so the element looks animated from the moment it is rendered through after it finishes. Q: How do the two times work in the animation shorthand? A: In the shorthand, the first time value is read as animation-duration and the second as animation-delay. Other longhands can appear in any order, but if you supply two times their position decides which is duration and which is delay. Q: What does animation-iteration-count: infinite do? A: It repeats the animation endlessly until the element is removed or play-state is set to paused. You can also use fractional counts such as 1.5 to stop partway through a cycle, which combines well with alternate direction. Q: How do steps() timing functions behave? A: steps(n) divides the animation into n equal jumps instead of smooth interpolation, useful for sprite sheets and typewriter effects. The optional second argument (jump-start, jump-end, jump-both, jump-none) controls whether the jump happens at the start or end of each interval. Q: Can CSS animations be driven by scroll? A: Yes. animation-timeline can reference a scroll() or view() timeline so progress is tied to scroll position rather than elapsed time, and animation-range restricts the scroll span. These scroll-driven animations are newer and need fallbacks for unsupported browsers. #### CSS At-Rules Reference URL: https://geratools.com/css-at-rules-reference A searchable CSS at-rule reference covering @media, @supports, @container, @layer, @keyframes, @font-face, @property and more, with syntax, whether it is a statement or block, nesting behaviour and browser support. How to use: 1. Search an at-rule: Type a name fragment such as media, layer or keyframes to filter the table to matching at-rules. 2. Check statement vs block: Read the block-type column to see whether the at-rule ends in a semicolon (a statement) or wraps a block of nested rules or descriptors. 3. Confirm nesting and support: Each row shows whether the at-rule can be nested inside other rules and its current browser support status. FAQ: Q: What is a CSS at-rule? A: An at-rule is a CSS statement that begins with an @ keyword and instructs the engine how to behave. Some are single statements ending in a semicolon, like @import, while others wrap a block of nested rules or descriptors, like @media or @font-face. Q: What is the difference between @media and @container? A: @media queries characteristics of the viewport or device, so styles respond to the whole window. @container queries the size or style of a nearest ancestor declared as a container, letting a component adapt to the space it is actually given regardless of the viewport. Q: What does @layer do? A: @layer declares cascade layers. Rules in an earlier layer lose to rules in a later layer regardless of specificity, which lets you order resets, frameworks and your own overrides predictably without specificity wars. Q: Where must @charset and @import go? A: @charset must be the very first bytes of the stylesheet with no preceding whitespace or comments. @import statements must appear at the top of the file too, after any @charset and @layer-statement declarations, before any style rules. Q: Why use @supports? A: @supports is a feature query: it applies its block only if the browser understands the property/value or selector you test. It lets you ship a modern layout while providing a fallback for engines that lack a feature, instead of guessing from user-agent strings. #### CSS Houdini APIs Reference URL: https://geratools.com/css-houdini-apis Reference for the CSS Houdini worklet and typed-OM APIs with registration syntax, input properties they read and current browser support status. How to use: 1. Pick the API: Search by name (Paint, Properties and Values, Typed OM) to find the worklet or registration API you need. 2. Copy the registration: Each entry shows the exact registerPaint / registerProperty / registerLayout call or addModule snippet. 3. Check support: Read the support note — Paint and Properties/Values ship widely; Layout and Animation are limited. FAQ: Q: What is CSS Houdini? A: Houdini is a set of low-level APIs that expose parts of the CSS engine to JavaScript. They let developers extend CSS — registering custom paint logic, typed custom properties, and layout — instead of waiting for new CSS features to be standardised and shipped. Q: How do I register a paint worklet? A: Define a class with a paint(ctx, size, props) method and call registerPaint('name', Class) inside a worklet file. Load it with CSS.paintWorklet.addModule('paint.js'), then reference it in CSS as background: paint(name). Q: What does registerProperty do? A: The Properties and Values API's CSS.registerProperty({ name, syntax, inherits, initialValue }) gives a custom property a type. A typed property like or can then be animated and transitioned, which untyped --vars cannot. Q: Which Houdini APIs have broad browser support? A: The Paint API (PaintWorklet) and the Properties and Values API (registerProperty) ship in Chromium-based browsers and are the most widely usable. The Layout and Animation worklets remain experimental or unshipped in several engines, so feature-detect before relying on them. Q: Is the Typed OM part of Houdini? A: Yes. The CSS Typed Object Model lets you read and write CSS values as typed JavaScript objects via element.attributeStyleMap and CSSStyleValue, avoiding fragile string parsing. It underpins the worklet APIs and is usable on its own. #### Lat/Lng to UTM Converter URL: https://geratools.com/lat-lng-to-utm Convert WGS-84 decimal latitude and longitude to Universal Transverse Mercator (UTM) coordinates. Get the zone number, hemisphere band, easting and northing in metres using the standard transverse Mercator projection on the WGS-84 ellipsoid. How to use: 1. Enter decimal coordinates: Type the WGS-84 latitude and longitude in signed decimal degrees, for example 51.4778 and -0.0014. 2. Read the UTM result: The tool computes the UTM zone from the longitude, then projects the point to easting and northing in metres on the WGS-84 ellipsoid. 3. Copy the UTM string: Copy the zone, hemisphere, easting and northing to paste into GIS software, a survey report or a handheld GPS unit. FAQ: Q: How is the UTM zone determined? A: The world is divided into 60 longitude zones, each 6 degrees wide. The zone number is floor((longitude + 180) / 6) + 1, giving zone 1 starting at 180 degrees west. A few exceptions exist around Norway and Svalbard. Q: What ellipsoid does this converter use? A: It uses the WGS-84 ellipsoid with semi-major axis 6378137 metres and flattening 1/298.257223563, the global standard used by GPS. Easting and northing are in metres. Q: What is the false easting and false northing? A: Each zone uses a false easting of 500000 metres so eastings are always positive. In the southern hemisphere a false northing of 10000000 metres is added so northings stay positive there too. Q: How accurate is the projection? A: The transverse Mercator series used here is accurate to well under a millimetre within a UTM zone, far beyond any practical surveying need. Accuracy degrades only far outside the zone's 6-degree band. #### robots.txt Validator URL: https://geratools.com/robots-txt-validator Parses robots.txt syntax per RFC 9309 and lets you test whether a specific URL would be allowed or disallowed for a given user-agent, applying most-specific-match and wildcard rules. Runs fully in-browser. How to use: 1. Paste robots.txt: Drop the contents of your robots.txt file into the editor. A sample with groups, wildcards, and a sitemap loads by default. 2. Choose a user-agent and URL: Enter a crawler name such as Googlebot and the path or full URL you want to test. 3. Read the verdict: The tool shows ALLOWED or DISALLOWED, which rule and group matched, and lists any syntax warnings it found. FAQ: Q: Which standard does this follow? A: It follows RFC 9309, the Robots Exclusion Protocol. The most specific matching rule wins, an Allow beats a Disallow of equal length, and the wildcard star and end-anchor dollar sign are supported. Q: How are groups matched to a user-agent? A: Each group has one or more User-agent lines. The tool picks the group whose agent token is the longest substring match of your user-agent, falling back to the star group if no specific name matches. Q: How is most-specific matching decided? A: Among all rules that match the path, the one with the longest pattern wins. If an Allow and a Disallow match with equal length, the Allow takes precedence, exactly as the standard specifies. Q: Does an empty Disallow block crawling? A: No. An empty Disallow value means allow everything for that group. The validator treats it as a no-op so it never disallows a path on its own. Q: Is my robots.txt sent anywhere? A: No. All parsing and URL testing run in your browser with JavaScript. Your file never leaves your device, so staging or internal robots files stay private. #### SendGrid / Twilio Email Event Types URL: https://geratools.com/sendgrid-event-types A searchable reference for SendGrid (Twilio) Event Webhook event types — processed, delivered, open, click, bounce, dropped, spamreport, unsubscribe and group events — each with category, key payload fields and meaning. Runs in your browser. How to use: 1. Search an event: Type a SendGrid event such as bounce, click, or deferred, or a keyword, to filter the index. 2. Read the category: Use the category column to separate delivery events from engagement and account events when building handlers. 3. Use the payload fields: Each event lists the key JSON fields it carries (such as reason, type, url) so you can map them to your database. FAQ: Q: What is the difference between a bounce and a dropped event in SendGrid? A: A bounce means the receiving server accepted then rejected the message, or rejected it during the SMTP conversation — the email reached a mail server. A dropped event means SendGrid never attempted delivery, usually because the address is on a suppression list (previous bounce, spam report, unsubscribe, or invalid). Q: What does a deferred event mean? A: A deferred event means the receiving server temporarily rejected the message (a 4xx SMTP response) and SendGrid will retry. It is not a failure — repeated deferrals over the retry window eventually turn into a bounce if the server never accepts the message. Q: How are open and click events tracked? A: Opens are tracked with a 1x1 tracking pixel inserted into HTML emails, so an open event fires when images load. Clicks are tracked by rewriting links to redirect through SendGrid, which records the original url field before forwarding. Both require the corresponding tracking setting to be enabled. Q: Which events should suppress future sends? A: Bounce (hard), dropped, spamreport, and unsubscribe events add the address to a suppression list and you should stop mailing it. Soft bounces and deferred events are transient. Group unsubscribe events (group_unsubscribe) only suppress a specific unsubscribe group, not all mail. Q: Is anything I search uploaded? A: No. The full event index and the search run entirely in your browser. Nothing you type is sent to any server. #### UTM to Lat/Lng Converter URL: https://geratools.com/utm-to-lat-lng Convert Universal Transverse Mercator (UTM) coordinates back to WGS-84 decimal latitude and longitude. Enter the zone, hemisphere, easting and northing in metres and get precise geographic coordinates using the inverse transverse Mercator projection. How to use: 1. Enter the UTM values: Type the zone number, choose the hemisphere, and enter the easting and northing in metres. 2. Read the geographic result: The tool runs the inverse transverse Mercator projection on the WGS-84 ellipsoid and returns the latitude and longitude in signed decimal degrees. 3. Copy the decimal pair: Copy the comma-separated latitude and longitude to paste into a map, API or spreadsheet. FAQ: Q: What inputs does UTM to lat/long need? A: It needs the zone number (1 to 60), the hemisphere (north or south), the easting in metres and the northing in metres. The hemisphere is required because northings repeat between the two halves of the globe. Q: Why does the hemisphere matter so much? A: In the southern hemisphere a false northing of 10000000 metres is added so values stay positive. Without knowing the hemisphere, the converter cannot tell whether a northing of 5000000 means the north or south half. Q: What ellipsoid is assumed? A: The WGS-84 ellipsoid is used, matching GPS and most modern datasets: semi-major axis 6378137 metres and flattening 1/298.257223563. Q: How accurate is the inverse projection? A: The Krüger series used here is accurate to sub-millimetre level inside the zone, so the recovered latitude and longitude match the original coordinates to well under a metre. #### CSS Mask Image Generator URL: https://geratools.com/css-mask-generator Free CSS mask-image generator. Create edge fades, spotlight and vignette masks with an adjustable falloff, preview them live on a sample tile, and copy a cross-browser mask-image plus -webkit-mask-image declaration. Runs in your browser. How to use: 1. Choose a mask style: Pick a fade direction, a centre spotlight, or an edge vignette from the buttons. 2. Adjust the falloff: Drag the fade-size slider to control how gradual the transition is. 3. Copy the CSS: Copy the generated mask-image and -webkit-mask-image declaration into your stylesheet. FAQ: Q: What does mask-image do in CSS? A: mask-image uses the alpha (or luminance) of a gradient or image to control which parts of an element are visible. Where the mask is opaque black the element shows fully; where it is transparent the element is hidden. A gradient mask therefore creates a smooth fade. Q: Why does the output include -webkit-mask-image? A: Some browsers, notably Safari, still require the -webkit- prefixed property for mask-image. Including both the prefixed and standard declarations ensures the mask works across all current browsers. Q: Does the mask change the image file? A: No. The mask is a CSS visual effect applied at render time. The underlying image is untouched, and no new image files are created — the mask itself is a gradient generated in CSS. Q: Can I use this to fade a background or a photo into the page? A: Yes. Apply the generated mask to any element with a background image or an img, and it will fade out along the direction you chose, letting the page behind it show through smoothly. #### CSS Grid Cheatsheet URL: https://geratools.com/css-grid-cheatsheet A searchable CSS grid cheatsheet covering the container, track sizing with fr and minmax, item placement, alignment and responsive recipes. Copy any property with one click. Runs entirely in your browser, nothing is uploaded. How to use: 1. Browse by topic: Properties are grouped into container setup, responsive track sizing, item placement, alignment and ready-made recipes. 2. Search for what you need: Type a property or goal like columns or auto-fit to filter the whole sheet instantly. 3. Copy the property: Click Copy next to any line to put the exact CSS on your clipboard, ready to paste into your stylesheet. FAQ: Q: How do I make a responsive grid without media queries? A: Use grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)). It fits as many 250px-plus columns as the width allows and stretches them to fill the row, reflowing automatically as the screen resizes. Q: What is the fr unit in CSS grid? A: fr is a fraction of the leftover free space in the grid container. grid-template-columns of 1fr 2fr gives two columns where the second is twice as wide as the first. Q: What is the difference between auto-fit and auto-fill? A: Both create as many tracks as fit. With auto-fit, leftover empty tracks collapse so existing items stretch to fill the row; with auto-fill, empty tracks are kept, leaving gaps. Use auto-fit for stretchy galleries. Q: How do I place an item across multiple columns? A: Use grid-column to span tracks, for example grid-column: 1 / 3 (from line 1 to line 3) or grid-column: span 2 to cover two columns from its current position. Q: Is anything I search or copy uploaded? A: No. The whole cheatsheet and its search run in your browser, so nothing you type or copy is ever sent anywhere. #### CSS Filter Generator URL: https://geratools.com/css-filter-generator Free CSS filter generator with live preview for blur, brightness, contrast, grayscale, hue-rotate, invert, opacity, saturate and sepia. Copy the filter property instantly. Runs entirely in your browser. How to use: 1. Adjust the sliders: Drag the blur, brightness, contrast and other sliders to shape the filter while the preview updates live. 2. Read the generated CSS: The filter property is built for you, omitting any function still at its default value. 3. Copy the code: Click Copy CSS to put the filter declaration on your clipboard. FAQ: Q: Which filter functions are supported? A: It covers blur, brightness, contrast, grayscale, hue-rotate, invert, opacity, saturate and sepia — chained in the order CSS expects. Q: Can I use this on background images and elements? A: Yes. The generated filter property applies to any element. For frosted-glass effects behind an element, pair it with backdrop-filter. Q: How do I make an image black and white in CSS? A: Use filter: grayscale(100%);. This generator sets it for you when you drag the grayscale slider to 100, and combines it with any other filters you add. Q: Does the order of filter functions matter? A: Yes. Filters are applied left to right, so blur(2px) brightness(120%) is not identical to brightness(120%) blur(2px). The generator chains them in a consistent order for predictable results. Q: Is anything uploaded? A: No — the preview and CSS are generated entirely in your browser. #### CSS Grid Generator URL: https://geratools.com/css-grid-generator Free visual CSS Grid generator — set columns, rows, gaps and track sizing, see a live preview, and copy ready-to-use grid CSS. Runs entirely in your browser. How to use: 1. Set columns and rows: Use the sliders to choose how many columns and rows your grid has. 2. Adjust gaps and sizing: Set the row and column gaps and pick flexible, fixed or content-based track sizing. 3. Copy the CSS: Click Copy CSS to grab the generated grid rules for your stylesheet. FAQ: Q: What is the difference between fr, px and auto tracks? A: fr distributes leftover space proportionally, px is a fixed pixel size, and auto sizes each track to fit its content. The generator switches all tracks between these for a quick preview. Q: How do I set the gap between grid items? A: Use the gap property, which is shorthand for row-gap and column-gap. This tool outputs gap as two values — row gap first, then column gap. Q: Is my layout sent anywhere? A: No — the grid CSS is generated entirely in your browser and nothing is uploaded. Q: What does repeat() do in the generated CSS? A: repeat() is shorthand that repeats a track size a set number of times. repeat(3, 1fr) is the same as writing 1fr 1fr 1fr, so it keeps the grid-template-columns value compact for many columns. Q: What does 1fr mean in CSS Grid? A: fr is the fractional unit. It splits the leftover space in the container after fixed sizes and gaps are accounted for. Three columns of 1fr each take one third of the available width and stay equal as the container resizes. Q: How do I make a responsive grid that wraps automatically? A: For auto-wrapping cards, use grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)) in your own CSS. This tool generates a fixed column count; the auto-fill/minmax pattern is the next step once you know the minimum card width. Q: When should I use Grid instead of Flexbox? A: Use Grid for two-dimensional layouts where you control rows and columns together, such as page or dashboard layouts. Use Flexbox for one-dimensional rows or columns of items. #### CSS Flexbox Playground URL: https://geratools.com/css-flexbox-playground Free CSS Flexbox playground — change flex-direction, justify-content, align-items, wrap and gap, watch a live preview, and copy the generated flexbox CSS. Runs entirely in your browser. How to use: 1. Choose container properties: Set flex-direction, justify-content, align-items and flex-wrap from the dropdowns. 2. Tune gap and item count: Drag the sliders to change the gap between items and how many items appear. 3. Copy the CSS: Click Copy CSS to grab the generated flex container rules. FAQ: Q: What is the difference between justify-content and align-items? A: justify-content positions items along the main axis (the flex-direction), while align-items positions them along the cross axis. Swapping flex-direction swaps which axis each one controls. Q: When should I use flexbox instead of grid? A: Flexbox is best for one-dimensional layouts — a single row or column of items. CSS Grid is better when you need to control rows and columns together in two dimensions. Q: Is anything uploaded? A: No — the flexbox CSS is generated entirely in your browser. Q: What does flex-direction change? A: flex-direction sets the main axis: row lays items left to right, column stacks them top to bottom, and the -reverse variants flip the order. It also decides which axis justify-content and align-items act on. Q: What is the difference between space-between, space-around and space-evenly? A: All three distribute extra space along the main axis. space-between puts no space at the ends and equal gaps between items; space-around gives each item equal space on both sides (so end gaps are half the inner gaps); space-evenly makes every gap, including the ends, identical. Q: How do I centre items both horizontally and vertically? A: Set justify-content: center and align-items: center on the flex container. With flex-direction: row this centres along both axes; the playground lets you confirm it visually before copying. Q: What does flex-wrap do? A: flex-wrap: nowrap keeps all items on one line, shrinking them if needed. wrap lets items flow onto new lines when they run out of room, and wrap-reverse does the same but stacks the new lines in the opposite direction. #### CSS Unit Converter URL: https://geratools.com/css-unit-converter Convert any CSS length between px, rem, em, pt, pc, in, cm, mm and Q at once, with configurable root and parent font sizes. Runs entirely in your browser, nothing is uploaded. How to use: 1. Enter a value and its unit: Type the length and choose the unit it is currently in — px, rem, em, pt, pc, in, cm, mm or Q. 2. Set the font sizes for rem and em: Adjust the root font size (used for rem) and the parent font size (used for em). Both default to 16px. 3. Read every equivalent: The value is shown converted into every CSS unit at once, with the input unit highlighted. FAQ: Q: How is px related to physical units like pt and in? A: CSS fixes 1 inch to 96px, so 1pt = 96/72 ≈ 1.333px, 1pc = 16px, 1cm ≈ 37.795px and 1mm ≈ 3.7795px. These are reference pixels, not necessarily the device's physical pixels. Q: Why do rem and em need a font size? A: rem is relative to the root element's font size and em is relative to the parent element's font size. With the default 16px root, 1rem = 16px; change the root or parent fields to match your CSS. Q: How many pixels is 1rem? A: With the default 16px root font size, 1rem equals 16px. Change the root font field to match your CSS and the conversion updates accordingly. Q: Is anything uploaded? A: No. All conversions run entirely in your browser — nothing you enter is sent to a server. #### Cubic Bezier Easing Editor URL: https://geratools.com/cubic-bezier-editor Free cubic-bezier easing editor for CSS animations. Drag the curve handles, scrub the timeline to read the eased value, compare against a reference curve, save your own easings and export ready-to-paste cubic-bezier() or @keyframes. 100% in your browser. How to use: 1. Drag the two handles: Grab the pink and indigo control points on the curve to shape your easing, or pick a preset like ease-out or ease-in-out-back to start from a known curve. 2. Preview and scrub: Watch the dot animate with your curve, change the animated property and duration, then drag the scrubber to read the exact eased value at any progress point. 3. Compare, save and export: Set a reference curve to compare against, save curves you like, then copy the cubic-bezier() value, a full transition rule or a generated @keyframes block. FAQ: Q: What is a cubic-bezier() easing function? A: In CSS, cubic-bezier() defines how an animation or transition accelerates over time. It is a curve through four points — a fixed start at (0,0), a fixed end at (1,1) and two control handles you move. The x-axis is progress through the animation and the y-axis is the eased output, so the shape of the curve decides whether motion eases in, eases out, snaps or overshoots. Q: Why must x1 and x2 stay between 0 and 1? A: The horizontal axis is time, which only ever moves forward. If a handle x-value left the 0–1 range the curve would fold back on itself and stop being a valid timing function, so the editor clamps the handle x to that range. The y-values are free to go above 1 or below 0, which is exactly how overshoot curves like ease-out-back are made. Q: How do I get a bounce or overshoot effect? A: Drag a handle above the top gridline (y greater than 1) or below the bottom one (y less than 0). The eased value briefly passes its target and springs back, which reads as a bounce. The built-in ease-out-back, ease-in-out-back and anticipate presets are good starting points to tweak. Q: What does the scrubber read-off tell me? A: It solves the curve for a given progress percentage and shows the eased output percentage. At 50 percent progress a linear curve outputs 50 percent, but an ease-out curve might already be at 80 percent — useful when you are timing a second animation to start when the first is visually most of the way done. Q: When would I export @keyframes instead of a single cubic-bezier value? A: Some properties cannot be eased with a timing function alone, or you may need the easing baked into a keyframe animation for a specific engine. The export samples your curve into percentage stops so the motion is reproduced as a keyframe animation you can paste directly into a stylesheet. Q: Is anything uploaded when I use this editor? A: No. The curve maths, preview, comparison and exports all run locally in your browser using plain JavaScript and SVG. Saved curves are kept in your browser localStorage only and never leave your device. #### CSS Pattern Generator URL: https://geratools.com/css-pattern-generator Free CSS pattern generator. Create repeating geometric backgrounds — stripes, polka dots, line grids, checkerboards and cross-hatch — pick your colours, tune the size, then copy pure CSS. No images, no network: everything runs in your browser. How to use: 1. Pick a pattern type: Choose stripes, diagonal stripes, polka dots, a line grid, a checkerboard or cross-hatch from the dropdown. 2. Set your two colours: Pick a background and a foreground colour, or hit Swap to flip them. Type a hex value directly for an exact brand colour. 3. Tune size, thickness and opacity: Drag the sliders to change the tile size, line or dot weight and the foreground opacity until the preview looks right. 4. Copy the CSS: Copy the full rule (with your selector) or just the background properties, or download a ready-to-use pattern.css file. FAQ: Q: How does a CSS pattern work without an image? A: Each pattern is built from repeating CSS gradients. A repeating-linear-gradient draws stripes or hatching, a radial-gradient draws dots, and offset linear gradients build the checkerboard. The browser tiles them with background-size, so the result is razor-sharp at any resolution and weighs nothing to download. Q: Which CSS properties does the tool output? A: It outputs four properties: background-color (the base), background-image (the repeating gradients), background-size (the tile dimensions) and background-position (the offset that aligns checks and graph-paper lines). Paste them into any selector and the pattern appears. Q: Will these patterns work in every browser? A: Yes. repeating-linear-gradient, radial-gradient and multiple background layers are supported in every modern browser — Chrome, Firefox, Safari and Edge — and have been for years. No vendor prefixes are needed for current versions. Q: Can I make a subtle, low-contrast texture? A: Lower the foreground opacity slider. At 100% the pattern is bold; drop it to 10-30% and you get a faint texture that sits quietly behind text — ideal for hero sections, cards and empty states without hurting readability. Q: How do I keep the pattern crisp on retina screens? A: Because the pattern is drawn by the browser from gradients rather than a bitmap, it is resolution-independent and stays perfectly sharp on high-DPI and retina displays. There is no pixelation to worry about, unlike a PNG texture. Q: Is my design saved, and is anything uploaded? A: Your current settings are saved in this browser via localStorage so the tool reopens where you left off. Nothing is ever uploaded — there is no network request, no account and no tracking of your colours or CSS. ### Generators #### API Key Setup Documentation Builder URL: https://geratools.com/api-key-documentation-builder Generate API key documentation covering where to generate the key, how to pass it in requests (header, bearer, or query), security best practices, rotation, and rate limits. Includes a live cURL example and exports as Markdown. How to use: 1. Describe the key and endpoint: Enter your API name, base URL, where the key is generated, and the header or scheme used to pass it. 2. Set the auth scheme and limits: Choose bearer, custom header, or query-string auth, and add your rate-limit numbers. The tool builds a matching cURL example. 3. Review and export: Check the generated request example and security section, then copy the Markdown into your docs. FAQ: Q: Should the key go in a header or the query string? A: Prefer a header — either Authorization: Bearer or a custom header like X-API-Key. Query-string keys leak into server logs, browser history, and referrer headers, so they are the least safe option and should only be used when a header is impossible. Q: How do I tell users to store the key safely? A: Tell them never to commit it to source control or ship it in client-side bundles. The key belongs in an environment variable or a secrets manager, read at runtime on the server. This builder includes that guidance in the security section automatically. Q: What should the rate-limit section say? A: State the limit (for example 100 requests per minute), the window, and what happens when it is exceeded — typically a 429 response with a Retry-After header. Documenting this up front stops developers from treating throttling as an outage. Q: Should I document key rotation? A: Yes. Explain how a user generates a new key and how long the old key keeps working during the overlap. Without a rotation story, a leaked key forces downtime, so a documented rotate-then-revoke flow is a security feature in itself. Q: What is the difference between an API key and a token? A: An API key is a long-lived static secret that identifies the caller. A token (such as an OAuth access token) is usually short-lived and scoped. Many APIs use a key for simple server-to-server calls and tokens for user-delegated access; document whichever your API uses and do not mix the terms. #### Barcode Generator (EAN / Code 128 / Code 39 / UPC) URL: https://geratools.com/barcode-generator Free online barcode generator. Create EAN-13, UPC-A, Code 39, and Code 128 barcodes as crisp scalable SVG, with automatic check-digit calculation and verification. All encoding runs in your browser — no data is transmitted. How to use: 1. Choose a symbology: Pick EAN-13, UPC-A, Code 39, or Code 128 set B depending on what your scanner or label needs. 2. Enter the data: Type the digits or text to encode. For EAN-13 and UPC-A you can omit the final check digit and it is added automatically. 3. Copy the SVG: A scalable barcode renders instantly. Copy the SVG markup to paste into a label, document, or web page. FAQ: Q: What is the difference between EAN-13 and UPC-A? A: EAN-13 is the 13-digit international retail barcode; UPC-A is the 12-digit North American version. UPC-A is actually EAN-13 with a leading zero, so this tool encodes them with the same underlying bars. Q: How is the check digit calculated? A: For EAN-13 each digit is multiplied by 1 or 3 by position, summed, and the check digit is whatever makes the total a multiple of 10. UPC-A uses the same modulo-10 idea with the weights swapped. The tool computes and verifies it for you. Q: When should I use Code 128 versus Code 39? A: Code 128 set B is compact and encodes the full printable ASCII range, ideal for shipping and internal labels. Code 39 is older, less dense, and limited to digits, uppercase letters, and a few symbols, but is supported by virtually every scanner. Q: Why is the output SVG instead of PNG? A: SVG is vector, so the barcode stays perfectly sharp at any size — crucial because a blurry or anti-aliased barcode can fail to scan. You can paste the SVG anywhere or rasterise it to PNG at the exact resolution you need. Q: Is my data sent anywhere? A: No. The barcode is built from the published encoding tables directly in your browser. Nothing about the value you enter leaves your device. #### ISO Shipping Container Size Reference URL: https://geratools.com/container-size-reference Reference table for ISO standard shipping container types with external and internal dimensions, door opening, tare weight, payload and cubic capacity, with unit toggle. How to use: 1. Pick a container type: Find the row for your container, from a 20ft standard to a 40ft high-cube or reefer. 2. Read internal vs external dimensions: External dimensions are the ISO footprint for stacking; internal dimensions and door opening determine what fits inside. 3. Toggle metric or imperial: Switch between metres and feet to match your shipping documents or warehouse measurements. FAQ: Q: What is a TEU? A: A TEU is a Twenty-foot Equivalent Unit, the standard measure of container ship capacity. One 20ft container equals 1 TEU and one 40ft container equals 2 TEU (one FEU, Forty-foot Equivalent Unit). Port and ship capacities are quoted in TEU. Q: What is a high-cube container? A: A high-cube (HC) container is about 30 cm (1 ft) taller than a standard container, giving roughly 2.69 m of internal height instead of 2.39 m. It is widely used for lightweight, voluminous cargo because it adds cubic capacity without changing the footprint. Q: Why is the internal volume less than length times width times height? A: Internal usable volume is reduced by corrugated walls, corner posts, the door frame and floor thickness. Quoted cubic capacity already accounts for these, so it is several percent below the raw internal dimension product. Q: What does tare and payload mean? A: Tare weight is the empty container's own weight. Payload (or net weight) is the maximum cargo it may legally carry. Tare plus payload equals the gross weight, which is capped by ISO and by road/rail limits at destination. Q: Is this reference calculated online? A: No. All dimensions and the unit conversion run locally in your browser. Nothing is sent anywhere. #### Fake Certificate Thumbprint Generator URL: https://geratools.com/fake-certificate-thumbprint-generator Generate certificate thumbprint strings in correct SHA-1 (40 hex) and SHA-256 (64 hex) formats for testing TLS and PKI code and UIs. These are random placeholders, not real certificate fingerprints. How to use: 1. Choose the hash algorithm: Pick SHA-1 for a 40-character thumbprint or SHA-256 for a 64-character one, matching the format your tool expects. 2. Choose the display format: Select colon-separated bytes, space-separated bytes, or plain uppercase hex. 3. Generate and copy: Click generate to produce cryptographically random bytes formatted as a thumbprint, then copy it with one click. FAQ: Q: Is this a real certificate fingerprint? A: No. The thumbprint is a string of cryptographically random bytes formatted to look exactly like a certificate fingerprint. It is not derived from any certificate and matches no real key, so use it only as placeholder test data. Q: What is a certificate thumbprint? A: A thumbprint, or fingerprint, is the hash of the DER-encoded certificate. SHA-1 produces 20 bytes shown as 40 hex characters, and SHA-256 produces 32 bytes shown as 64 hex characters. Tools use it to identify a specific certificate compactly. Q: Why are SHA-1 thumbprints still around? A: SHA-1 is cryptographically broken for signatures, but many tools and Windows certificate stores still display SHA-1 thumbprints as identifiers. The format persists for compatibility even though SHA-256 is preferred for any security decision. Q: Which display format should I use? A: Colon-separated uppercase hex (AA:BB:CC) is common in OpenSSL and browsers. Space-separated bytes appear in Windows certificate dialogs. Plain hex with no separators suits config files and string comparisons. Pick whichever your tool reads. Q: Are the bytes truly random? A: Yes. The tool uses the browser's Web Crypto random generator to produce the bytes, so each thumbprint is unpredictable and unlikely to ever repeat. They are still placeholders, not hashes of any actual data. #### Fake Company Generator URL: https://geratools.com/fake-company-generator Generates fake company names, industries, registration numbers, websites, and contact details for B2B demos and test CRM data. Builds plausible but entirely fictional records that never reference a real business. How to use: 1. Set how many companies: Choose the number of fictional companies you need, from one for a demo to a batch for a CRM seed. 2. Generate: Click Generate to assemble company names, an industry, a registration number, a website, and a contact email for each. 3. Copy the data: Copy a single company block or the whole batch as tab-separated rows for pasting into a spreadsheet or import file. FAQ: Q: Are these real companies? A: No. Every name is built by combining random word parts with a legal suffix such as Ltd or GmbH, and the registration numbers and contacts are random. They do not refer to any real business, registered entity, or trademark. Q: How are company names built? A: The generator combines a random prefix root, an optional second word, and an industry-style suffix, then appends a legal entity type. This produces plausible names like Northbridge Analytics Ltd without copying any existing company. Q: Are the registration numbers valid? A: They follow a plausible length and format (for example an eight-digit UK-style company number) but are randomly generated and not checked against any registry. They are placeholders for filling fields, not lookups. Q: Can I use the generated email and website? A: The email and website are derived from the fake company name on example or common test domains, so they look realistic but are not guaranteed to exist. Treat them as test-only values. Q: Is anything transmitted anywhere? A: No. Every field is generated locally in your browser with no network calls, so the data stays on your device. #### Fake Company Registration Number Generator URL: https://geratools.com/fake-company-registration-number-generator Generate company registration number strings in the correct format for major jurisdictions — UK Companies House numbers, US EIN, and German Handelsregister numbers. Realistic structure for testing business and onboarding tools. For demo use only. How to use: 1. Pick a jurisdiction: Choose UK Companies House, US EIN, or German Handelsregister to match the format your tool expects. 2. Set how many to generate: Enter a count and click Generate to produce that many correctly-formatted, randomly-built numbers. 3. Copy the list: Copy individual values or the whole list to seed forms, databases, and test fixtures. FAQ: Q: Are these real company numbers? A: No. They are randomly generated strings that merely follow the structural format of each jurisdiction. They are not registered to any real company and should never be used to impersonate a business. Q: What is the format of a UK company number? A: A UK Companies House number is eight characters — either eight digits for England and Wales, or a two-letter prefix such as SC for Scotland or NI for Northern Ireland followed by six digits. This tool generates both styles. Q: What format does a US EIN follow? A: An Employer Identification Number is nine digits written as two digits, a hyphen, then seven digits (XX-XXXXXXX). The first two digits are an IRS campus prefix; this tool only uses prefixes from the published valid ranges. Q: Does this tool send data anywhere? A: No. All formats and random generation run entirely in your browser, so nothing is created on or sent to a server. Q: Can I use these in production? A: No. They are for development, demos, and test fixtures only. Validating them against a real registry such as Companies House or the IRS will fail because no such company exists. #### Random GPS Coordinates Generator URL: https://geratools.com/fake-coordinates-generator Generate random GPS coordinate pairs with options for approximate land, ocean, polar, or fully random points. Latitude is sampled correctly so points spread evenly over the globe — ideal for map app testing and geospatial demos. How to use: 1. Choose a region mode: Pick anywhere, approximate land, ocean, polar, or a custom bounding box to constrain where points fall. 2. Set count and precision: Enter how many pairs to generate and how many decimal places of precision you need. 3. Generate and copy: Click Generate to produce lat/lon pairs, then copy the list into your test data or map. FAQ: Q: Why does the tool not pick latitude uniformly in degrees? A: Picking latitude uniformly between minus 90 and 90 would over-sample the poles, because lines of latitude get shorter toward each pole. To spread points evenly over the sphere the tool uses latitude equals arcsine of (2u minus 1), where u is a uniform random number. Q: How accurate is the land or ocean filter? A: It is approximate. The tool uses a handful of continental bounding boxes rather than a true coastline map, so a land point could fall on a lake and an ocean point could land on a small island. It is good enough for plausible test data, not for geographic accuracy. Q: What coordinate format is produced? A: Each line is a decimal-degrees pair written as latitude, longitude, for example 51.507351, -0.127758. Latitude ranges from minus 90 to 90 and longitude from minus 180 to 180. Q: Can I restrict points to a specific area? A: Yes. Choose the custom bounding box mode and enter your own latitude and longitude minimum and maximum values. Every generated point will fall inside that rectangle. Q: Does this need an internet connection? A: No. All sampling happens in your browser with no map tiles or API calls, so you can generate unlimited coordinates offline. #### Fake Email Generator URL: https://geratools.com/fake-email-generator Creates realistic-looking but non-existent email addresses from name patterns and safe example domains. Useful for seeding test databases and filling forms without hitting real inboxes or leaking real addresses. How to use: 1. Choose a domain style: Pick a safe example domain (such as example.com) or a placeholder consumer-style domain so the addresses suit your test. 2. Set the count and pattern: Enter how many addresses you need and the format, like first.last or first initial plus last name. 3. Generate and copy: Click Generate to build the addresses, then copy one or the whole batch into your fixtures. FAQ: Q: Will these email addresses receive mail? A: No. They use reserved example domains (example.com, example.org, example.net) or placeholder domains that are not real mailboxes, so any message sent to them simply bounces. They exist to fill fields safely. Q: Why use example.com instead of gmail.com? A: example.com, example.org, and example.net are reserved by the IETF (RFC 2606) specifically for documentation and testing, so they will never belong to a real person. Using them avoids accidentally emailing or impersonating a real Gmail or Outlook user. Q: Are the addresses unique? A: The generator appends a small random number when needed and varies the local part, so a batch is very unlikely to collide. For guaranteed uniqueness in large datasets, you can also include a sequence number in your import step. Q: Can I control the name format? A: Yes. Choose patterns such as first.last, firstlast, f.last, or first_last, and the tool builds the local part from randomly paired first and last names accordingly. Q: Does anything get sent to a server? A: No. Addresses are generated locally in your browser with no network requests, so nothing is logged or transmitted. #### Fake IBAN Generator (Test) URL: https://geratools.com/fake-iban-generator Produces structurally correct IBANs for multiple European countries using the right length, BBAN layout, and a real MOD-97 check-digit calculation. Intended for testing payment integrations in sandbox environments, not real transfers. How to use: 1. Choose a country: Pick a country so the IBAN gets the correct two-letter code, total length, and BBAN structure. 2. Set how many: Enter the number of IBANs to generate for seeding test payment data. 3. Generate and copy: Click Generate to build MOD-97-valid IBANs, then copy one or all for your sandbox tests. FAQ: Q: Are these real bank accounts? A: No. The bank and account portions are randomly generated, so the IBAN does not belong to any real account and cannot receive money. Only the structure and the MOD-97 check digits are correct, which is what format validators check. Q: How are IBAN check digits calculated? A: Move the four leading characters (country code plus two check digits) to the end, convert every letter to a number (A=10 … Z=35), interpret the whole string as one big integer, take it modulo 97, and the check digits are 98 minus that remainder. A correct IBAN always gives a final remainder of 1. Q: Why do IBAN lengths differ by country? A: Each country registers its own IBAN length and BBAN layout with SWIFT. Germany is 22 characters, France 27, Spain 24, the UK 22, and so on. This tool stores the registered length and structure per country. Q: Will these pass a SEPA validator? A: They will pass IBAN format and MOD-97 check-digit validation, which is what most client-side and API validators run. They will not pass a real bank-account existence check, because no such account exists. Q: Does this contact any server? A: No. The IBAN and its check digits are computed entirely in your browser, so nothing is sent or stored anywhere. #### Fake Medical Record Generator URL: https://geratools.com/fake-medical-record-generator Generate fake patient medical record summaries with ICD-10 diagnosis codes, medication lists, vitals, and visit history. Entirely fictional data for building and testing health software safely. Dev use only. How to use: 1. Set the record count: Choose how many fictional patient records you need, from one to twenty-five in a single batch. 2. Select an output style: Pick a readable summary card view or JSON for pasting into seed scripts and test fixtures. 3. Generate and reuse: Click Generate to produce fresh anonymized records, then copy them into your development database or unit tests. FAQ: Q: Is this real patient data? A: Absolutely not. Every patient, diagnosis, medication, and date is randomly generated and fictional. No record corresponds to a real person, so there is no privacy or HIPAA concern in using it for development. Q: Are the ICD-10 codes valid? A: The codes are drawn from a curated list of real, common ICD-10 codes paired with their descriptions. They are formatted correctly, but the combinations are random and not clinically meaningful. Q: Can I demo a health app with this? A: Yes, for internal demos and testing. Clearly label the data as synthetic. Never present generated records to clinicians or patients as though they describe a real individual. Q: Does it include medications and dosages? A: Yes. Each record lists one to four medications with a plausible name and dose. The pairings are random, so do not interpret any combination as a real prescription. Q: What vitals are included? A: Each record carries randomized but in-range vitals: blood pressure, heart rate, temperature, and BMI. Ranges are chosen to look realistic for UI layout and validation testing. #### Fake Passport Number Generator URL: https://geratools.com/fake-passport-number-generator Generate passport number strings in the correct format for major countries — 9-digit US, 9-character UK, 8-digit Canadian, alphanumeric Schengen patterns and more — for testing travel, KYC, and booking forms. These are format-only stubs, not valid travel documents. How to use: 1. Choose a country: Select the issuing country so the tool applies that nation's passport number length and character pattern. 2. Set a batch size: Enter how many numbers you need to test lists, imports, or repeated submissions. 3. Generate and copy: Click Generate, then copy a single value or the whole list into your test forms. FAQ: Q: Are these real passport numbers? A: No. They only follow the public length and character-pattern rules for each country (for example, the US uses 9 digits, the UK uses 9 alphanumeric characters). The actual value is random and corresponds to no issued document. Q: Why do formats differ by country? A: Each passport authority defines its own document-number scheme. The US issues 9 numeric digits, Canada uses 2 letters plus 6 digits, the UK uses 9 digits, and many EU states mix letters and digits. The tool encodes a representative pattern per country. Q: Can these pass a real verification? A: No. They are designed to pass front-end format checks only. No fake number will validate against a government database or an MRZ check-digit verification of a genuine document. Q: Is it legal to generate these? A: Generating format-only test strings for software QA is fine. Using a passport-shaped number to impersonate someone, cross a border, or deceive an institution is a serious crime. Use these strictly for development. Q: Does this send data anywhere? A: No. All values are produced locally in your browser. Nothing is uploaded, stored, or logged. #### Fake Person Profile Generator URL: https://geratools.com/fake-person-profile-generator Generates a full fake person profile including name, date of birth, address, phone, email, and job title. Ideal for populating test databases and demo UIs with realistic but entirely fictional placeholder data. How to use: 1. Choose options: Pick how many profiles to generate and which locale flavour you want for names and addresses. 2. Generate profiles: Click generate to produce complete fictional profiles with consistent name, email, age, and contact details. 3. Copy the data: Copy a single profile or the whole batch as JSON to paste straight into your seed scripts or demo UI. FAQ: Q: Are these real people? A: No. Every field is randomly combined from generic word pools entirely in your browser. The names, addresses, phone numbers, and emails are fictional and any resemblance to a real person is coincidental. Q: Is the email tied to the generated name? A: Yes. The email is derived from the first and last name with a sample domain, so each profile is internally consistent, which is exactly what you usually want for test fixtures. Q: Can I export the profiles as JSON? A: Yes. Use the copy-as-JSON button to grab the whole batch in a structured array, ready to drop into seed scripts, fixtures, or a mock API. Q: Are the phone numbers callable? A: No. Phone numbers use reserved or clearly fictional ranges and formats, so they will not connect to a real subscriber. Use them only as placeholder display values. Q: Is anything sent to a server? A: No. Generation happens fully client-side. No profile data leaves your browser and nothing is stored or logged. #### International Fake Phone Number Generator URL: https://geratools.com/fake-phone-number-generator-international Generate phone numbers with realistic country-code formatting for 30+ countries, using each nation's fictional or reserved number ranges where they exist. Choose a country, get correctly-prefixed E.164 and national-format numbers for testing international phone validation. How to use: 1. Choose a country: Select from 30+ countries; each applies its own dialling code, national number length, and reserved range where one exists. 2. Set a batch size: Enter how many numbers you need to test lists, imports, or pagination. 3. Generate and copy: Click Generate to get both E.164 and national formats, then copy any number or the whole list. FAQ: Q: Are these real phone numbers? A: No. Where a country reserves a fictional block (such as UK 07700 900xxx or US 555-01xx), the tool uses it. Elsewhere it uses plausible prefixes with random subscriber digits, so the combination is fabricated and should never be dialled. Q: What is E.164 format? A: E.164 is the international telephone numbering standard: a plus sign, the country calling code, then the national subscriber number with no spaces, up to 15 digits total. Most global APIs require it. Q: Why does each country have a different length? A: National number lengths vary — France has 9 significant digits, Germany varies, India has 10, Japan differs by line type. The tool encodes a representative length per country so the output looks correct. Q: Can I trust the country dialling codes? A: Yes — the calling codes (like +44, +49, +91, +81) are the real ITU-assigned codes. Only the subscriber digits are randomised, and reserved fiction blocks are used where available. Q: Is anything sent to a server? A: No. All generation runs locally in your browser. Nothing is uploaded, stored, or logged. #### Fake Purchase Order Generator URL: https://geratools.com/fake-purchase-order-generator Generate fake purchase order documents with a PO number, vendor, buyer, line items, quantities, unit prices, and correctly computed subtotal, tax, and total. Realistic, internally consistent test data for procurement and ERP demos. How to use: 1. Set the tax rate: Enter the tax percentage you want applied so the totals match the jurisdiction your software targets. 2. Generate a PO: Press generate to produce a fictional purchase order with a number, vendor, buyer, and a set of priced line items. 3. Copy or reroll: Copy the document as text for use as a test fixture, or reroll to produce a fresh, different purchase order. FAQ: Q: Are the totals calculated correctly? A: Yes. Each line total is quantity times unit price, the subtotal is the sum of all line totals, the tax is the subtotal times your chosen rate, and the grand total is subtotal plus tax. Everything is rounded to two decimal places so it reconciles. Q: Is this real purchase order data? A: No. Every vendor, buyer, PO number, and amount is randomly generated and fictional. It exists only to give procurement and ERP software realistic-looking input without using anyone's real records. Q: Can I control the currency? A: The amounts are shown as plain numbers with two decimal places and no currency symbol, so you can treat them as whatever currency your test environment uses. Only the tax rate is configurable. Q: How many line items does each PO have? A: Each purchase order has between two and five distinct line items drawn at random from a catalogue, with quantities and unit prices generated within realistic ranges for each item type. Q: Is anything sent to a server? A: No. All catalogues and the calculation logic are bundled into the page, so generation happens entirely in your browser with no network requests and no data leaves your machine. #### Fake SSN Generator (US Test Format) URL: https://geratools.com/fake-ssn-generator Generate US Social Security number format strings (AAA-GG-SSSS) using area numbers 900-999, which the SSA has never issued and never will. The output is structurally correct for form testing but can never match a real SSN. Strictly for QA, never for fraud. How to use: 1. Choose how many you need: Enter a count to generate a batch of unique test SSN strings at once. 2. Pick a format: Choose dashed AAA-GG-SSSS or 9 plain digits depending on what your form expects. 3. Generate and copy: Click Generate, then copy a single value or the entire list into your test fixtures. FAQ: Q: Why use area numbers 900-999? A: The Social Security Administration has never assigned and will never assign area numbers in the 900-999 range; these were used historically only for taxpayer ID purposes and are invalid as SSNs. That guarantees the output can never collide with a real person's number. Q: Are these valid SSNs? A: No, deliberately not. They follow the correct nine-digit AAA-GG-SSSS shape so they pass format checks, but the 900-999 area block makes them permanently invalid as actual Social Security numbers. Q: Is it legal to use these? A: Generating format-only test strings for software QA is fine. Using any SSN-like number to impersonate a person, open accounts, or commit fraud is a serious crime. This tool is strictly for development. Q: What do the parts of an SSN mean? A: An SSN is AAA-GG-SSSS: a 3-digit area number, a 2-digit group number, and a 4-digit serial number. The group and serial are never all zeros in valid numbers, and this tool avoids those zero edge cases too. Q: Does anything get sent to a server? A: No. All values are generated locally in your browser with a random generator. Nothing is uploaded, stored, or logged. #### Fake Stock Price Generator URL: https://geratools.com/fake-stock-price-generator Free fake stock price generator. Creates a fictional ticker and a daily OHLC price series using a geometric random walk with adjustable volatility. Ideal for financial dashboard demos and trading UI prototypes, all in your browser. How to use: 1. Set the series options: Choose a starting price, number of trading days, daily volatility and an optional drift. A random ticker symbol is generated, or you can keep re-rolling for one you like. 2. Generate the series: Click Generate to build a daily open, high, low and close series using a geometric random walk, so prices move in believable percentage steps. 3. Copy as CSV or JSON: Switch the output format and copy the OHLC series into a charting library, spreadsheet or trading-UI prototype. FAQ: Q: What model produces the prices? A: A geometric random walk. Each day's close equals the prior close multiplied by (1 + drift + volatility times a random shock). Open, high and low are derived around the close, so the series behaves like a real price path with proportional moves rather than fixed steps. Q: What does the volatility setting do? A: Volatility scales the size of each day's random move as a percentage. A low value gives a calm, slowly drifting line; a high value produces sharp swings. It maps directly to the magnitude of the daily shock in the random walk. Q: Is the ticker symbol real? A: No. The ticker is a random three- or four-letter symbol and any resemblance to a real listed company is coincidental. The whole series is fictional placeholder data for demos and prototypes. Q: Can I export OHLC for candlestick charts? A: Yes. Each row includes date, open, high, low, close and volume, which is the standard shape for candlestick and OHLC charts. Export as CSV with a header or as a JSON array of objects. Q: Does anything get sent to a server? A: No. The series is generated locally in your browser with a random number generator and never uploaded, so you can prototype offline and keep your data private. #### Support Ticket Generator URL: https://geratools.com/fake-support-ticket-generator Create realistic fake customer support tickets with subject, description, requester, priority, category, status, and timestamps. Generate up to 100 records as copyable JSON for testing helpdesk platforms, Zendesk-style demos, and customer support tooling. How to use: 1. Choose how many tickets: Enter a number between 1 and 100 for how many fake support tickets you want generated at once. 2. Generate: Click Generate tickets to draw a fresh random batch with subjects, requesters, priorities, categories, statuses, and timestamps. 3. Copy the JSON: Use Copy JSON to put the full array on your clipboard, ready to paste into a seed script, fixture file, or mock API. FAQ: Q: Is any of the data real? A: No. Every name, email, subject, and ticket ID is randomly assembled from built-in word banks. Emails use reserved test domains like example.com so they can never reach a real person. Q: What fields does each ticket include? A: Each ticket has an ID, subject, description, requester name, email, priority, category, status, plus created and updated ISO timestamps within the last 30 days. Q: Can I use this for load or integration testing? A: Yes. Generate up to 100 tickets at a time and copy the JSON into your fixtures or seed data. Run it repeatedly to build a larger combined dataset. Q: Are the timestamps realistic? A: Yes. Each createdAt falls within the last 30 days and the matching updatedAt is always equal to or later than it, so chronological ordering stays valid. Q: Does anything get uploaded? A: No. Generation happens entirely in your browser with no network calls, so the data never leaves your device. #### Fake Twitter/X Profile Generator URL: https://geratools.com/fake-tweet-profile-generator Generate fictional Twitter/X-style profile data for UI mockups: display name, @handle, bio, location, follower and post counts, join date, and an avatar seed. Seedable so the same input reproduces the same profile for consistent screenshots. How to use: 1. Optionally enter a seed: Leave the seed blank for a random profile, or type any text to get a deterministic profile that reproduces exactly the next time you use the same seed. 2. Generate the profile: Press generate to assemble a name, handle, bio, location, counts, and a join date from the bundled word lists. 3. Copy the data: Use the rendered preview directly, or copy the JSON to drop into your mockup, fixture, or design file. FAQ: Q: Is the generated profile a real account? A: No. Every field is fabricated locally from bundled word lists and a seeded random generator. The handles, names, and counts do not correspond to any real Twitter/X account, and nothing is fetched from the platform. Q: What does the seed do? A: The seed makes generation deterministic. If you type the same seed text you get the exact same profile every time, which is useful when you need identical mockups across screenshots, design files, and test fixtures. Leaving it blank produces a fresh random profile each time. Q: Where does the avatar come from? A: The tool generates an avatar seed string and builds a DiceBear avatar URL from it. DiceBear is a public open-source avatar service that renders a consistent illustrated face for any seed, so no real photo is involved. Q: Can I use this to impersonate someone? A: No. The tool exists for UI mockups, design demos, and test data only. Using fabricated profiles to impersonate real people or deceive others violates platform rules and may be illegal. Keep it to fictional placeholder content. Q: How are the follower and post counts chosen? A: They are random values within realistic ranges (followers up to roughly 90K, posts up to roughly 25K) and formatted with K and M suffixes the way the real platform displays them. They carry no real meaning and exist only to make mockups look believable. #### Fake VAT Number Generator URL: https://geratools.com/fake-vat-number-generator Generate VAT number strings that follow the correct national format for EU member states, including the country prefix, exact length, and a valid check digit where the country uses one. For testing EU tax and compliance tools — not real registrations. How to use: 1. Choose a country: Select the EU member state whose VAT format you need; each country has its own length and rules. 2. Generate numbers: Set how many you want and click Generate to produce correctly-formatted VAT strings with valid check digits where applicable. 3. Copy for testing: Copy individual numbers or the whole batch to seed forms, fixtures, and validation tests. FAQ: Q: Are these real, registered VAT numbers? A: No. They follow the structural format and, where applicable, the check-digit algorithm of each country, but they are random and not registered to any business. Checking them against the EU VIES service will return not valid. Q: Do the numbers include a valid check digit? A: For countries with a published, deterministic check digit — such as Germany and the Netherlands — yes, the final digit is computed correctly so the number passes a local format check. Countries without a simple public algorithm get correctly-formatted random digits. Q: What is the country prefix for? A: An EU VAT number starts with a two-letter ISO country code, such as DE for Germany or FR for France, followed by the national number. The prefix tells systems which country's format and rules apply. Q: Does this send anything to a server? A: No. All format rules and check-digit maths run in your browser, so numbers are generated locally and nothing is uploaded. Q: Can I use these to register or trade? A: No. They are strictly development and test data. Using a fabricated VAT number for real transactions would be invalid and potentially unlawful. #### Fake Vehicle VIN Generator URL: https://geratools.com/fake-vehicle-vin-generator Generates Vehicle Identification Numbers (VINs) that pass the ISO 3779 check digit algorithm. Useful for testing automotive database schemas and VIN lookup tools. Synthetic data only, runs in your browser. How to use: 1. Choose a quantity: Enter how many VINs you need, from 1 to 50, depending on your test fixture size. 2. Generate the VINs: Click Generate to produce 17-character strings whose position-9 check digit is computed to satisfy the ISO 3779 algorithm. 3. Copy into your tests: Use Copy all to grab the newline-separated list and paste it straight into seed data or a test case. FAQ: Q: Are these VINs real? A: No. They are synthetic strings that satisfy the VIN check-digit math but do not correspond to any registered vehicle. Use them only for testing parsers, validators, and database schemas, never to misrepresent a real car. Q: What is the position-9 check digit? A: The 9th character of a VIN is a checksum derived from the other 16 characters. Each character is transliterated to a number, multiplied by a positional weight, summed, and reduced mod 11. The remainder (0-9, or X for 10) is the check digit. Q: Why are the letters I, O, and Q never used? A: The VIN standard excludes I, O, and Q because they are easily confused with the digits 1 and 0. This generator draws only from the 33 permitted characters, so its output always uses the legal alphabet. Q: Will these pass a real VIN validator? A: They pass the check-digit validation step, which is the only purely mathematical check. A full decoder that looks up the World Manufacturer Identifier or model year against a real database may still reject them because the prefixes are random. Q: Is my data sent anywhere? A: No. Generation happens entirely in your browser using JavaScript. Nothing is transmitted to a server, so the tool works offline and keeps your test fixtures private. #### Open Source License Picker & Generator URL: https://geratools.com/license-picker-builder Compare MIT, Apache 2.0, GPL v3, LGPL v3, MPL 2.0, BSD 3-Clause, and ISC with a decision guide on permissions, conditions, and copyleft, then generate the full LICENSE text with your name and year filled in, ready to drop into your repository. How to use: 1. Compare the licenses: Read the comparison table to see which licenses are permissive, which are copyleft, and what conditions each imposes. 2. Pick one and enter your details: Select a license, then type the copyright holder name and year to fill the placeholders in the license text. 3. Copy the LICENSE file: Copy the generated text and save it as a file named LICENSE in the root of your repository. FAQ: Q: What is the difference between permissive and copyleft licenses? A: Permissive licenses like MIT and Apache let others use, modify, and distribute your code with almost no obligations beyond keeping the notice. Copyleft licenses like GPL require derivative works to be released under the same license, keeping them open. Q: When should I choose Apache 2.0 over MIT? A: Apache 2.0 is like MIT but adds an explicit patent grant and a requirement to state significant changes, which gives users patent protection. Choose it for larger projects or where patent clarity matters; MIT is simpler for small libraries. Q: What does GPL v3 require? A: GPL v3 is a strong copyleft license. Anyone who distributes your code or a modified version must make the full source available under GPL v3, and cannot add restrictions. It protects software freedom but limits use in closed-source products. Q: What is LGPL for? A: LGPL is a weaker copyleft aimed at libraries. You can link the library into proprietary software without that software becoming GPL, but modifications to the library itself must stay open under LGPL. Q: Is the generated text legally valid? A: The texts are the official, unmodified license texts with only the name and year placeholders filled in, which is exactly how they are meant to be applied. For high-stakes projects you should still confirm the choice with a lawyer. #### Mock .env File Generator URL: https://geratools.com/mock-env-file-generator Generate realistic .env file contents with common variable patterns: DATABASE_URL, API keys, secrets, ports, and feature flags. Useful for project scaffolding, onboarding docs, and testing dotenv parsers with safe fake values. How to use: 1. Choose variable groups: Select which categories to include — database, auth and secrets, third-party APIs, app settings — to match your stack. 2. Pick a value style: Choose realistic fake values or placeholder markers if you want an .env.example template instead of filled values. 3. Generate and copy: Click Generate to produce dotenv-formatted KEY=value lines and copy them to your clipboard or save as a .env file. FAQ: Q: What is the .env file format? A: A .env file is a plain text file of KEY=value lines, one per line, with UPPER_SNAKE_CASE keys by convention. Lines starting with # are comments, and values containing spaces are typically wrapped in double quotes. This tool follows those rules. Q: Are the secret values real? A: No. Every secret, API key, and password is randomly generated fake data with no connection to any real service. They are safe to commit to documentation, but you should never use generated secrets in production. Q: When should I use placeholder style? A: Use placeholder style to produce an .env.example file for a repository. It keeps the variable names but replaces values with markers like your-api-key-here, so contributors know what to fill in without leaking real credentials. Q: Why are some values quoted? A: Values that contain spaces or special characters are wrapped in double quotes so dotenv parsers read them as a single value. Simple values without spaces are left unquoted, matching common dotenv conventions and keeping the file readable. #### N-gram Generator URL: https://geratools.com/ngram-generator Free n-gram generator that extracts character or word n-grams (bigrams, trigrams, and higher) from your text, with counts and optional case folding. Useful for NLP experimentation, language modeling demos, and text-analysis tooling. Runs entirely in your browser. How to use: 1. Paste your text: Enter or paste the text you want to break into n-grams. 2. Choose mode and n: Pick character or word n-grams and set n to 2 for bigrams, 3 for trigrams, and so on. 3. Read the n-gram counts: Each distinct n-gram is listed with how many times it occurs, sorted most-frequent first. FAQ: Q: What is an n-gram? A: An n-gram is a contiguous sequence of n items from a text. Word bigrams are pairs of adjacent words; character trigrams are runs of three characters. They are a basic building block of language models and text classification. Q: What is the difference between character and word n-grams? A: Character n-grams slide over individual characters and capture spelling and sub-word patterns, while word n-grams slide over tokens and capture phrasing. Character n-grams are robust to typos; word n-grams capture meaning. Q: How are word n-grams tokenized? A: Text is split into Unicode word tokens — runs of letters, numbers, and apostrophes — so contractions stay intact and punctuation is dropped. The n-gram window then slides one token at a time. Q: Why are some n-grams missing? A: A text of length L yields L minus n plus 1 n-grams, so if your text is shorter than n items you get none. Increase the text length or lower n. Q: Is my text uploaded? A: No. All n-gram extraction runs entirely in your browser with JavaScript, so your text never leaves your device. #### TOTP Secret Generator URL: https://geratools.com/otp-secret-generator Generate base32-encoded TOTP secrets compatible with Google Authenticator, Authy, 1Password, and other RFC 6238 apps. Builds the otpauth URI and a scannable QR code entirely in your browser using the Web Crypto API. How to use: 1. Set the account details: Enter the issuer (your app or service name) and the account label, usually a username or email, so the authenticator shows a clear entry. 2. Generate the secret: Click Generate to create a fresh random base32 secret from the Web Crypto API, along with the matching otpauth URI. 3. Enroll the device: Scan the QR code with an authenticator app, or paste the base32 secret manually, then store the secret securely in your backend. FAQ: Q: What is a TOTP secret? A: A TOTP secret is a shared random key, encoded in base32, that both your server and the user's authenticator app hold. Each app derives the same time-based 6-digit code from it using the RFC 6238 algorithm, so codes match without any network call. Q: Why base32 and not hex? A: The TOTP standard and authenticator apps expect the secret in base32 because it uses only uppercase letters and digits 2 to 7, which are unambiguous to read and type manually. The otpauth URI also requires base32. Q: How long should the secret be? A: RFC 4226 recommends at least 128 bits, and 160 bits (20 bytes) is common and matches the SHA-1 HMAC block. This tool defaults to 20 bytes, producing a 32-character base32 secret, which works with all mainstream apps. Q: Is the secret generated securely? A: Yes. The random bytes come from crypto.getRandomValues, the browser's cryptographically secure RNG, and both the secret and QR code are built locally. Nothing is transmitted, so treat the secret as a live credential. Q: What goes in the otpauth URI? A: The URI follows otpauth://totp/Issuer:label?secret=BASE32&issuer=Issuer&algorithm=SHA1&digits=6&period=30. Authenticator apps parse it from the QR code to provision the account with the correct parameters automatically. #### Placeholder Name Generator (Mx. / Gender-Neutral) URL: https://geratools.com/placeholder-name-mx Generate gender-neutral and non-binary coded placeholder names for demo accounts, user research, and inclusive UI mockups. Outputs with the Mx. honorific and avoids gendered defaults. How to use: 1. Choose options: Select how many names you need and whether to include the Mx. honorific and a sample email handle. 2. Generate the list: Generate a batch of gender-neutral first and last name pairs suitable for demos and test data. 3. Copy into your mockup: Copy the list and paste it into your prototype, seed file, or research script. FAQ: Q: Why use gender-neutral placeholder names? A: Default demo data often skews toward stereotypically gendered names, which can unintentionally signal who a product is for. Gender-neutral names keep mockups and research neutral and inclusive. Q: What is the Mx. honorific? A: Mx. is a gender-neutral honorific used in place of Mr., Mrs., or Ms. It is widely recognized in the UK and elsewhere and is the standard choice for non-binary or unspecified-gender placeholders. Q: Are these real people? A: No. The names are assembled from common unisex first names and surnames purely for demo and testing purposes. Any resemblance to a real person is coincidental and not intended. Q: Can I use these in production seed data? A: Yes, they work well as seed data for staging and demos. For load testing with very large volumes you may want a dedicated faker library, but for handfuls of inclusive examples this is ideal. #### Random API Response Generator URL: https://geratools.com/random-api-response-generator Free random API response generator. Produce plausible JSON for common REST resources — user, product, order and event — with realistic ids, names, prices and timestamps. Mock backend responses for frontend development without a live server, all in your browser. How to use: 1. Pick a resource type: Choose user, product, order or event. Each produces a JSON object shaped like a typical REST resource of that kind, with sensible fields and value types. 2. Choose how many records: Set a record count from one to fifty. A single unwrapped record returns one object; multiple records return an array. 3. Copy the JSON: Optionally wrap the array in a data and meta envelope, then click Copy to paste the response into your mock server, fixture file or fetch stub. FAQ: Q: What resource types can I generate? A: Four common REST resources: user (id, name, email, role, timestamps), product (sku, name, category, price, rating, stock), order (order number, status, line items, total) and event (analytics-style type, ids and properties). Each field uses a realistic value and the correct JSON type. Q: Is the JSON valid and well-formed? A: Yes. The output is produced with JSON.stringify and pretty-printed with two-space indentation, so it parses cleanly in any JSON tool, language, or mock server without manual cleanup. Q: What does the data and meta envelope do? A: When enabled, an array of records is wrapped as { data: [...], meta: { total, page, per_page } }. This mirrors the pagination envelope that many REST and JSON:API style backends return, which makes your mock closer to the real response shape. Q: Are the records realistic enough for demos? A: They are designed to look plausible — real-sounding names, valid-format emails, ISO 8601 timestamps, two-decimal prices and UUID-style ids. They are fake placeholder values, so never treat them as real user data. Q: Does anything get sent to a server? A: No. All generation runs locally in your browser. The tool never contacts a backend, so you can mock responses offline and nothing you generate is transmitted anywhere. #### Random Calendar Event Generator URL: https://geratools.com/random-calendar-event-generator Generate fake calendar events with realistic titles, start and end times, durations, locations, and attendee lists. Ideal for demoing calendar UIs, populating scheduling app mockups, and seeding agenda test fixtures. How to use: 1. Choose a count: Pick how many fake events you need, from a single meeting to a batch for seeding a demo calendar. 2. Generate: Click Generate to build events with a title, start and end time, duration, location, and a list of attendees. 3. Copy: Copy one event or the whole batch to paste into your test fixtures, mock API, or demo data file. FAQ: Q: Are the dates real or guaranteed to be free slots? A: They are fabricated for testing only. Each event lands on a 15-minute slot within the next 30 days between 08:00 and 18:00, but the tool does not check for conflicts or real availability. Q: What does each event include? A: Every event has a title, a start time, an end time, a duration in minutes, a location, and one to four attendee names. The end time is always the start plus the duration so the two stay consistent. Q: Can I use these in a real calendar import? A: You can paste them into demos and test fixtures, but they are not formatted as iCalendar (.ics) files. Treat them as plain mock data, not production calendar entries. Q: Why are events sorted by time? A: After generating, the list is sorted by start time so it reads like a real agenda. This makes it easier to eyeball a sequence of meetings in a demo. Q: Does anything leave my browser? A: No. Every event is generated locally with no network calls, so your test data never leaves your device. #### Random Git Commit Message Generator URL: https://geratools.com/random-commit-message-generator Generate fake git commit messages in Conventional Commits format with types like feat, fix, chore, docs, and refactor, optional scopes, and occasional breaking-change markers. Useful for seeding demo git history and testing changelog generators. How to use: 1. Choose a count: Pick how many commit messages you need, from a handful to a full batch for seeding a demo repository. 2. Generate: Click Generate to produce Conventional Commits messages with a type, an optional scope, and a description. 3. Copy: Copy one message or the whole list into your demo commits, changelog fixtures, or release-notes tests. FAQ: Q: What format do the messages follow? A: They follow the Conventional Commits 1.0.0 format: a type, an optional scope in parentheses, an optional exclamation mark for breaking changes, then a colon and a short description — for example feat(auth): add multi-factor login. Q: Which commit types are used? A: The common Conventional Commits types: feat, fix, chore, docs, refactor, test, style, perf, build, and ci. Each type draws from descriptions that make sense for that category of change. Q: Why do some messages have an exclamation mark? A: An exclamation mark after the type or scope marks a breaking change, per the spec. The generator adds it occasionally to feat and refactor commits so your changelog tooling can be tested against breaking-change detection. Q: Can these be used to test a changelog generator? A: Yes. Because they follow Conventional Commits, tools like standard-version or release-please will group them by type and pick up the breaking-change markers, making them ideal fixtures for changelog testing. Q: Does anything leave my browser? A: No. All messages are generated locally with no network calls, so nothing is sent anywhere. #### Design Token Set Generator URL: https://geratools.com/random-design-token-set-generator Generates design token sets following the W3C Design Tokens (DTCG) format: color ramps, a modular type scale, spacing, shadows, and border-radius tokens with $value and $type. Reproducible from a seed, in your browser. How to use: 1. Set a seed: Enter any integer seed, or click Randomize. The same seed always produces the same token set, so output is reproducible. 2. Preview the ramp: The primary color ramp renders as swatches so you can sanity-check hue and contrast before exporting. 3. Copy the DTCG JSON: Click Copy DTCG JSON to grab the full token tree, ready to drop into a design-tokens pipeline or build step. FAQ: Q: What format are the tokens in? A: They follow the W3C Design Tokens Community Group (DTCG) draft format. Each token is an object with a $value and a $type, and tokens are nested under group names like color, spacing, and shadow. Q: Are the colors generated randomly? A: They are seeded, not truly random. A base hue is derived from your seed, and the accent hue is offset by roughly 150 to 210 degrees to stay visually complementary. The same seed always yields the same palette. Q: What type scale does it use? A: A 1.25 (major third) modular scale anchored at a 16px base. Sizes step up and down geometrically, which is a common, harmonious choice for design-system typography. Q: Can I use this output directly in code? A: The JSON is valid DTCG and can be fed to token transformers such as Style Dictionary, which convert it into CSS variables, Sass, JSON, or platform-specific formats. #### Election Result Generator URL: https://geratools.com/random-election-result-generator Generate fictional election results with candidate names, party labels, vote counts, and percentages that always sum to 100 percent. Useful for civic tech, voting apps, and political data visualization demos. How to use: 1. Set the contest: Enter a constituency name and how many candidates are standing in the contest. 2. Choose total votes: Set the total number of valid votes cast; the tool splits them across candidates randomly. 3. Generate and copy: Generate the result and copy the JSON, with vote shares that always add up to 100 percent. FAQ: Q: Do the percentages always add to 100? A: Yes. Votes are split as random integers that sum exactly to the total you enter, and percentages are computed from those counts then rounded so the displayed shares add to 100 percent. The leading remainder is assigned to the winner so rounding never breaks the total. Q: Are candidate and party names real? A: No. Names are drawn from generic placeholder pools and parties use neutral fictional labels. Nothing references a real person, party, or actual election. Q: How is the winner determined? A: The candidate with the most votes is marked the winner, and the tool reports the margin over the runner-up in both votes and percentage points. Ties are extremely unlikely given random integer splitting but the highest count always wins. Q: Can I control turnout or invalid ballots? A: The total you enter represents valid votes counted. To model turnout, treat the total as a fraction of an electorate you track separately; this tool focuses on the candidate split of valid votes. Q: What is the output format? A: A JSON object with the constituency, total votes, the winning candidate, and an array of candidates each with name, party, votes, and percentage. It drops straight into a results table or chart. #### Random Error Message Generator URL: https://geratools.com/random-error-message-generator Generate fake application error messages across HTTP status codes, form validation failures, and system-level errors. Useful for testing error-state UI components, designing error screens, and exercising error-handling code paths. How to use: 1. Choose an error type: Pick HTTP status, validation, or system errors — or leave it on mixed to get a spread of all three. 2. Generate: Click Generate to produce errors, each with a category, a code, and a human-readable message. 3. Copy: Copy a single error or the full batch into your test fixtures, mock responses, or error-state stories. FAQ: Q: Are the HTTP messages accurate? A: Yes. Each HTTP entry pairs a real status code with its standard meaning — 404 with Not Found, 429 with Too Many Requests, 503 with Service Unavailable, and so on — so the copy matches what the code actually represents. Q: What do validation errors look like? A: They reference a field name (like email or password) and a common rule failure, such as required, invalid format, too long, or mismatched confirmation. This mirrors how form libraries report errors. Q: What are the system errors? A: They use familiar OS and runtime error names like ECONNREFUSED, ETIMEDOUT, ENOSPC, and EACCES, plus database and memory failures, each with a short explanation. A pseudo hex code is attached for realism. Q: Can I use these as real API responses? A: They are plain text suited to filling UI slots and test fixtures, not fully structured JSON error envelopes. Wrap them in your own response shape when you need a realistic payload. Q: Does anything leave my browser? A: No. Every error is generated locally with no network calls, so nothing is sent anywhere. #### Forum Post Generator URL: https://geratools.com/random-forum-post-generator Generate fake forum thread JSON with titles, body text, categories, upvotes, view counts and nested replies. Prototype community platforms and discussion-forum UIs with realistic placeholder data, all in your browser. How to use: 1. Set thread and reply counts: Choose how many threads to create and the maximum number of replies any single thread can have. 2. Regenerate for variety: Click Regenerate to reshuffle titles, body text, authors, upvotes and view counts while keeping the structure consistent. 3. Copy the JSON: Copy the threads-and-replies JSON into your forum component, fixture file or mock API endpoint. FAQ: Q: What does each thread contain? A: Every thread has an id, a question-style title, a category, an author, multi-sentence body text, an upvote count, a view count, a reply count, a pinned flag, a creation timestamp and an array of reply objects. Each reply has its own id, author, body and upvotes. Q: How are the reply counts decided? A: Each thread gets a random number of replies from zero up to the maximum you set, so some threads will have no replies and others will be near the cap, matching how real forums look. The replyCount field always equals the length of the replies array. Q: Are the timestamps realistic? A: Yes. Thread creation times fall within the last ninety days of a fixed base date and are formatted as ISO 8601, so you can sort threads by recency just like a real forum. Q: Will the data fit my forum component? A: It uses a conventional threads array with nested replies, the shape most discussion UIs model, so it loads into community-platform and forum components with little or no remapping. Q: Is anything sent to a server? A: No. Threads are generated locally in your browser from a seeded random source. Nothing is uploaded, and identical settings reproduce identical data until you regenerate. #### Random HTTP Header Generator URL: https://geratools.com/random-http-header-generator Generate realistic HTTP request and response header name-value pairs drawn from standard, RFC-defined headers. Useful for testing HTTP tooling, building mock servers, and demonstrating header-based features. How to use: 1. Choose request or response: Select whether you want request headers, response headers, or a mix of both. 2. Set the count: Pick how many distinct header lines to generate in this batch. 3. Generate and copy: Each line is a realistic header name with a plausible random value. Copy the whole block as raw header text. FAQ: Q: Are the header names standard? A: Yes. Every header name comes from a built-in table of standard, RFC-defined HTTP headers such as Content-Type, Cache-Control, and Authorization, split into request and response sets. Q: Are the values real? A: The values are plausible, format-correct samples generated to match each header, such as a Bearer token shape for Authorization or a valid date for Date. They are fabricated for testing, not captured from real traffic. Q: What is the difference between request and response headers? A: Request headers are sent by the client and describe the request or the client, such as Accept and User-Agent. Response headers are sent by the server and describe the response or the server, such as Content-Type and Set-Cookie. Some headers can appear in both. Q: Can I paste the output straight into a tool? A: Yes. The output uses the standard Name: value format, one header per line, so you can paste it into curl config, a REST client, or a mock server definition with minimal editing. Q: Why generate random headers? A: Randomized but valid headers are useful for fuzzing parsers, populating mock responses, and demonstrating how middleware reacts to a range of headers, instead of testing against only the handful you wrote by hand. #### Random Invoice Generator URL: https://geratools.com/random-invoice-generator Produces fake invoice records with line items, quantities, unit prices, subtotal, tax, and grand total. Useful for testing accounting software, invoice management tools, and financial UI mockups. How to use: 1. Set the tax rate: Enter the VAT or sales-tax percentage to apply and choose how many invoices to create. 2. Generate: Click generate to build each invoice with random line items, a correctly summed subtotal, tax, and grand total. 3. Copy text or JSON: Copy a readable invoice or structured JSON to seed your accounting tool test data. FAQ: Q: Are the totals calculated correctly? A: Yes. The subtotal is the sum of each line item's quantity times unit price, the tax is the subtotal times your tax rate, and the grand total is subtotal plus tax, all rounded to two decimals. Q: Are these real invoices? A: No. Every invoice is fabricated at random in your browser from generic company names and item descriptions. They reference no real business or transaction. Q: What does each invoice contain? A: An invoice number, issue and due dates, a fictional supplier and customer, two to five line items with quantity and unit price, plus a subtotal, tax amount, and grand total. Q: Can I export structured data? A: Yes. The JSON copy returns objects with the invoice fields and a lineItems array, ready for fixtures, seed scripts, or component stories. Q: Does it store or transmit anything? A: No. All generation and arithmetic happen client-side. Nothing is sent to a server and nothing is saved. #### Random Job Posting Generator URL: https://geratools.com/random-job-posting-generator Creates realistic fake job postings with title, company, location, salary, requirements, and a description. Useful for testing job board platforms, recruiting tool interfaces, and HR demo data. How to use: 1. Set how many postings: Choose the number of job postings you want to generate. 2. Generate: Click generate to assemble each posting from random titles, companies, locations, salaries, and requirements. 3. Copy text or JSON: Copy a readable listing or structured JSON to seed your job board test database. FAQ: Q: Are these real job vacancies? A: No. Every posting is fabricated at random in your browser from generic word lists. They reference no real employer, role, or opening. Q: What fields does each posting include? A: Each posting has a job title, fictional company name, location, employment type, a salary range, three to five requirements, and a short description paragraph. Q: Can I export the data as JSON? A: Yes. The JSON copy gives you an array of objects with title, company, location, type, salary, requirements, and description fields ready for fixtures or seed scripts. Q: Are the salary figures realistic? A: They are plausible ranges generated within sensible bounds, but they are random placeholders, not market data. Replace them with real figures before publishing. Q: Does the tool store or transmit anything? A: No. All generation happens client-side from built-in lists. Nothing is sent to a server and nothing is saved. #### Random Push Notification Generator URL: https://geratools.com/random-notification-generator Generate fake mobile push notification content across social, e-commerce, news, finance, and messaging apps. Useful for testing notification systems, populating UI component libraries, and designing notification screens with realistic copy. How to use: 1. Pick a category: Choose an app category — social, e-commerce, news, finance, or messaging — or leave it on mixed for a variety pack. 2. Generate: Click Generate to produce notifications with an app name, a title line, and a body line typical of that vertical. 3. Copy: Copy one notification or the whole batch into your component stories, design mockups, or test fixtures. FAQ: Q: What app categories are supported? A: Social, e-commerce, news, finance, and messaging. Each category uses copy patterns typical of that vertical, such as order-shipped alerts for e-commerce or payment-received alerts for finance. Q: What does each notification contain? A: An app name, a short title, and a body line. Together they mirror the structure most mobile push notifications use, which makes them drop-in content for a notification list or banner component. Q: Are the app names real? A: No. The app names are invented placeholders so the notifications look realistic without referencing actual brands. They are safe to use in public mockups and screenshots. Q: Can I use these to test a real push pipeline? A: They are text content only, not actual push payloads with tokens or APNs/FCM structure. Use them to fill UI and copy slots; build real payloads separately for delivery testing. Q: Does anything leave my browser? A: No. All notification text is generated locally with no network calls, so nothing is sent anywhere. #### Sports Score Generator URL: https://geratools.com/random-sports-score-generator Generate realistic fake sports scores and match summaries across football, basketball, cricket, tennis, and soccer using sport-appropriate scoring ranges. Useful for sports platform UI prototyping, demos, and test data. How to use: 1. Pick a sport: Choose the sport so scores fall in a realistic range and the summary uses the right terminology. 2. Set how many matches: Enter the number of fixtures to generate and optionally a seed for repeatable results. 3. Copy the output: Generate the matches and copy them as JSON for use in your mockups or test fixtures. FAQ: Q: Are the scores realistic for each sport? A: Yes. Each sport uses its own scoring model — soccer goals are low single digits, basketball points are in the 80 to 130 range, and tennis is generated as best-of-three sets with valid game counts. This avoids the absurd numbers a single random range would produce. Q: Is the output deterministic? A: If you supply a seed, the same seed always produces the same matches, which is handy for reproducible test fixtures and screenshots. Leave the seed blank to get fresh random results each time you generate. Q: Can I use this data publicly? A: It is entirely fictional, so it is safe for demos and mockups. Team names are generic placeholders and no real fixtures, players, or results are referenced. Q: How are tennis sets handled? A: Tennis is generated as a best-of-three-sets match. Each set ends at six games with a two-game margin, or seven to five and seven to six for tiebreak sets, and the match winner is whoever takes two sets. Q: What format is the copyable output? A: A JSON array of match objects with home and away team, the score, the winner, and a short text summary. You can paste it directly into a fixtures array or a test seed file. #### Terms of Service Clause Generator URL: https://geratools.com/random-terms-of-service-clause-generator Generate fictional terms-of-service clause text for common platform policy sections such as acceptable use, accounts, termination, and liability. For demo, prototyping, and UI-testing use only — not legal advice. How to use: 1. Select clause sections: Tick the policy sections you want, such as acceptable use, accounts, termination, or limitation of liability. 2. Add placeholder details: Enter a service name and governing-law region to drop into the generated clauses so the demo reads coherently. 3. Generate and copy: Click Generate to build the clauses, then copy the full draft for use in mockups and prototypes. FAQ: Q: Is this generated text legally enforceable? A: No. It is fictional placeholder copy for demos, prototypes, and UI testing only. Enforceable terms of service must reflect your actual product, business model, and jurisdiction, so always have a qualified lawyer prepare or review them. Q: When would I use placeholder terms text? A: Designers and developers need realistic legal copy to fill out a page layout, test scrolling and reflow on a terms page, or demo a document-management feature before the real wording exists. Topical placeholder clauses look far more believable than lorem-ipsum. Q: Does it cover everything a real ToS needs? A: No. It touches common sections in plain language but omits many provisions a real agreement requires, such as payment terms, warranties, indemnities, and dispute resolution tailored to your jurisdiction. Q: Does the tool upload my service name? A: No. The clause templates and generation logic are bundled into the page, so everything is assembled in your browser and nothing you type is uploaded. Q: Can I edit the output? A: Yes. It is plain text you can paste into any editor and rewrite. For production, replace every clause with reviewed wording specific to your business and legal jurisdiction. #### Random User Agent Generator URL: https://geratools.com/random-user-agent-generator Generates valid, realistic user-agent strings for Chrome, Firefox, Safari, and Edge across desktop and mobile platforms. Useful for testing UA-detection logic, analytics parsing, and responsive behaviour. Runs entirely in your browser. How to use: 1. Pick browser and platform: Choose a browser and operating system, or leave them on Any to draw from the full pool of combinations. 2. Set how many to generate: Enter the number of user-agent strings you need and click generate to produce a fresh batch. 3. Copy the strings: Copy a single string or the whole list to use in tests, request headers, or mock analytics data. FAQ: Q: Are these real, valid user-agent strings? A: Yes. Each string follows the documented format for its browser and platform, using realistic version numbers and the correct token order, so it parses correctly in user-agent libraries and matches what real browsers send. Q: Why would I need to generate user agents? A: Common uses are testing user-agent detection branches, validating analytics or log parsers, seeding mock data, and checking that responsive or feature-gating logic behaves correctly for different browser and device combinations. Q: Do mobile strings include the right tokens? A: Yes. Mobile Chrome and Safari strings include the platform tokens such as Android version and device class, or iPhone OS version, plus the Mobile or Mobile Safari markers that detection code relies on. Q: Should I use these to disguise my browser? A: These are intended for legitimate testing and mock data. Spoofing your user agent to bypass access controls or terms of service is a different use case, and many sites detect inconsistencies between the UA string and other signals. Q: Does this contact any server? A: No. Strings are assembled locally in JavaScript from version tables and templates, so nothing is sent anywhere and it works offline. #### Recovery Codes Generator URL: https://geratools.com/recovery-codes-generator Generate sets of one-time backup recovery codes in the standard xxxx-xxxx format used by GitHub, Google, and other 2FA systems. Built on the Web Crypto API and runs entirely in your browser, with configurable count, length, and grouping. How to use: 1. Set the count and format: Choose how many codes to generate and how many characters each code should contain, optionally grouped with a hyphen for readability. 2. Generate the set: Click Generate to draw a fresh batch of codes from the Web Crypto API. Each code is independent and unpredictable. 3. Store the codes safely: Copy or download the codes and store them somewhere the user can reach without their primary device, such as a password manager or printed sheet. FAQ: Q: What are recovery codes for? A: Recovery codes are single-use backup credentials that let a user regain access to an account if they lose their primary two-factor device. Each code works once, so a typical service issues a set of ten that the user stores safely. Q: How should recovery codes be stored on the server? A: Never store them in plain text. Hash each code the same way you hash passwords, with a slow algorithm and per-code salt, and mark a code as used once it is redeemed so it cannot be reused. Q: Are these codes generated securely? A: Yes. Every code is built from crypto.getRandomValues, the browser's cryptographically secure RNG. They are not derived from a predictable sequence, so each one is independent and unguessable. Q: What format do services like GitHub use? A: Most services use short alphanumeric codes grouped for readability, such as five characters, a hyphen, then five more. This tool lets you match that style or choose your own length and grouping. Q: Can a user reuse a recovery code? A: No, by design. Each recovery code should be valid for exactly one login, after which the server marks it consumed. The user is usually prompted to regenerate a fresh set once most codes are used. #### Password Salt Generator URL: https://geratools.com/salt-generator Generate cryptographically random salts in hex and base64 for password hashing and key-derivation functions like bcrypt, scrypt, and Argon2. Powered by the Web Crypto API and runs entirely in your browser, with no value ever sent to a server. How to use: 1. Choose a salt size: Select how many random bytes the salt should hold. 16 bytes (128 bits) is the standard recommended size for password hashing. 2. Pick an output format: Choose hex or base64 depending on how your hashing library expects the salt to be stored. 3. Generate and store: Click Generate to draw fresh bytes from the Web Crypto API, then store the unique salt alongside each user's password hash. FAQ: Q: What is a salt and why do I need one? A: A salt is random data combined with a password before hashing. It ensures two users with the same password get different hashes and defeats precomputed rainbow-table attacks. A unique salt per password is mandatory for secure storage. Q: How big should a salt be? A: The widely recommended minimum is 16 bytes (128 bits) of random data. Many key-derivation functions accept larger salts, and 32 bytes is also common, but 16 bytes is sufficient to guarantee uniqueness across realistic user counts. Q: Should each password have its own salt? A: Yes, always. The whole point of a salt is uniqueness, so every password hash must use a fresh, independently generated salt. Reusing one salt for many users reintroduces the rainbow-table weakness salts are meant to prevent. Q: Can I store the salt with the hash? A: Yes. Salts are not secret and are normally stored in plain text next to the hash they produced, often concatenated into the same field. Their security value comes from uniqueness and randomness, not from being hidden. Q: Is the salt generated securely and privately? A: Yes. The tool uses crypto.getRandomValues, the browser's cryptographically secure RNG, and everything runs locally. No salt is transmitted or logged anywhere. #### Sample E-commerce Dataset Generator URL: https://geratools.com/sample-dataset-ecommerce Generates a synthetic e-commerce dataset with products, SKUs, prices, categories, stock levels, and ratings, exportable as JSON or CSV. Perfect for demoing shopping platforms, analytics dashboards, and import pipelines. Runs entirely in your browser. How to use: 1. Set the row count: Choose how many products you want in the dataset, from a few rows for a demo to a few hundred for a full catalog. 2. Pick the export format: Select JSON for APIs and seed scripts, or CSV for spreadsheets and bulk-import tools. 3. Copy or download: Copy the generated dataset to your clipboard, then paste it into your seed file, mock API, or import pipeline. FAQ: Q: What fields does each product have? A: Each row includes an id, a generated name, a SKU, a category, a price, a discount percentage and resulting sale price, stock quantity, an in-stock boolean, a rating out of five, a review count, and a short SKU-based description. Prices and discounts are internally consistent. Q: Is the sale price correct relative to the discount? A: Yes. The sale price is computed as price times one minus the discount percentage, rounded to two decimals. So a 50 priced item with a 20 percent discount shows a sale price of 40, keeping the dataset arithmetically valid for analytics tests. Q: Can I export to CSV for a spreadsheet? A: Yes. CSV mode produces a header row followed by one line per product, with fields quoted where needed so names containing commas do not break columns. Paste it straight into a spreadsheet or a bulk-import tool. Q: Is the data realistic? A: Names combine real adjectives, materials, and product nouns, categories are drawn from common retail departments, and prices, ratings, and stock follow plausible ranges. It is synthetic but reads like a believable catalog for demos and screenshots. Q: Does any data leave my browser? A: No. The dataset is generated locally in JavaScript and serialised on the page, so nothing is uploaded. It is safe for confidential demos and works offline. #### Sample Healthcare Dataset Generator URL: https://geratools.com/sample-dataset-healthcare Produces synthetic patient records with demographics, diagnoses, vitals, and visit dates as CSV or JSON. Useful for health-tech dashboard demos, EHR prototypes, and medical data tool testing without exposing real PHI. How to use: 1. Set the row count: Choose how many fake patient records you need, from a handful for a quick mock-up to a few thousand for load testing. 2. Pick a format: Select CSV for spreadsheets and BI tools, or JSON for feeding directly into an API or frontend prototype. 3. Generate and copy: Click Generate to build the records in your browser, then copy the output or download it as a file. FAQ: Q: Is any of this data real? A: No. Every name, diagnosis, and date is randomly generated in your browser from fixed sample pools. Nothing is fetched from a real medical record, so there is no PHI and nothing leaves your device. Q: Can I use this for HIPAA testing? A: Yes. Because the data is fully synthetic and contains no real identifiers, it is safe to use in non-production environments where real PHI is not allowed. Always confirm against your own compliance policy. Q: What fields are included? A: Each record has a patient ID, name, age, sex, a primary diagnosis with ICD-10 code, blood pressure and heart-rate vitals, and a last-visit date. The diagnosis codes are drawn from common real ICD-10 entries for realism. Q: How are the diagnoses chosen? A: Each record is randomly assigned one entry from a fixed list of common conditions paired with its real ICD-10 code, such as Type 2 diabetes (E11.9) or essential hypertension (I10). This keeps the data plausible for demos. Q: Will the same data regenerate every time? A: No. Each click produces a fresh random set. If you need a reproducible dataset, generate once and save the output rather than regenerating. #### Sample HR Dataset Generator URL: https://geratools.com/sample-dataset-hr Creates fake employee datasets with names, departments, job titles, salaries, hire dates, and managers as CSV or JSON. Ideal for testing HR software, org-chart tools, payroll systems, and people-analytics dashboards. How to use: 1. Set the headcount: Choose how many employee records to generate, from a small team to a large company for testing. 2. Pick a format: Select CSV for spreadsheets and payroll imports, or JSON for HRIS APIs and frontends. 3. Generate and export: Click Generate to build the records in your browser, then copy or download them. FAQ: Q: Are these real employees? A: No. Every name, salary, and date is randomly generated locally in your browser from sample pools. The data is fully synthetic and never leaves your device. Q: What fields are produced? A: Each record has an employee ID, full name, email, department, job title, a salary appropriate to the role, hire date, and a manager ID. The first employees are seeded as managers so the manager links resolve. Q: Do the manager references form a valid org chart? A: Yes, loosely. The first few generated employees are treated as managers, and everyone else is assigned one of their IDs. This gives a single tier of management you can render as a basic org chart. Q: How are salaries calculated? A: Each job title has a realistic salary band, and the salary is drawn at random within that band. Senior and engineering roles sit higher than entry-level or support roles, so analytics demos look plausible. Q: Can I generate the same set twice? A: No. Each generation is independently random. If you need a fixed dataset for tests, generate once and save the output. #### Sample IoT Sensor Dataset Generator URL: https://geratools.com/sample-dataset-iot Generates synthetic IoT sensor time-series data — temperature, humidity, and pressure — with device IDs and evenly-spaced timestamps as CSV or JSON. Useful for testing IoT dashboards, time-series databases, and telemetry pipelines. How to use: 1. Set readings and interval: Choose how many readings per device and the seconds between each timestamp to control the time span. 2. Set device count and format: Pick how many sensor devices to simulate and whether to output CSV or JSON. 3. Generate and export: Click Generate to build the series in your browser, then copy or download it. FAQ: Q: Is this real sensor data? A: No. Every reading is generated locally in your browser using a random walk around realistic baselines. Nothing is captured from a real device and no data leaves your browser. Q: What metrics are included? A: Each row has a device ID, an ISO timestamp, temperature in Celsius, relative humidity as a percentage, and atmospheric pressure in hectopascals. Values stay within physically plausible ranges. Q: How realistic is the time series? A: Each metric uses a random walk: the next value drifts a small amount from the previous one rather than jumping randomly. This produces smooth, correlated trends that look like real sensor telemetry rather than noise. Q: How are timestamps spaced? A: Readings are evenly spaced by the interval you set, counting backward from now. With a 60-second interval and 100 readings, the series spans the last 100 minutes ending at the current time. Q: Can I simulate multiple devices? A: Yes. Set the device count and the tool emits a full series for each device, each with its own ID and independent random walk, interleaved by device in the output. #### ISO 6346 Container Type Code Reference URL: https://geratools.com/shipping-container-iso-code Decode the four-character ISO 6346 container size and type code into length, height, and container type. Includes a reference of type groups (general purpose, reefer, open top, flat rack, tank) and common full codes used on shipping documents. How to use: 1. Enter the code: Type the four-character ISO 6346 size and type code from the container or shipping document. 2. Read the breakdown: The tool splits the code into length, height and width, and container type group. 3. Compare with the table: Use the type-group and common-code tables to confirm the meaning or look up another code. FAQ: Q: What does an ISO 6346 size and type code look like? A: It is four characters, for example 22G1. The first character is the length, the second is the height and width, the third is a letter for the container type, and the fourth is a numeric subtype. It is shown on the container alongside the owner code and check digit. Q: What does the code 22G1 mean? A: 22G1 is a 20-foot, standard-height general-purpose dry box. The first 2 means 20 feet long, the second 2 means 8 feet 6 inches high, G means general purpose with no ventilation, and the 1 is the standard subtype. It is the most common container type in service. Q: How do I tell a high-cube container from the code? A: Look at the second character. A digit of 5 means a height of 9 feet 6 inches, which is a high-cube container, while 2 means the standard 8 feet 6 inches. So 45G1 is a 40-foot high-cube dry box and 42G1 is a 40-foot standard-height one. Q: What is the difference between the size code and the BIC owner code? A: The size and type code is the four-character group describing the box's dimensions and type. The BIC owner code is a separate 11-character identifier: four letters for the owner and category, six serial digits, and a check digit. They appear together but encode different things. Q: Which type letter is a refrigerated container? A: The letter R in the third position marks a refrigerated container, or reefer. R0 and R1 are integral reefers with their own refrigeration unit, while R2 and R3 are insulated boxes served by an external clip-on plant. So 45R1 is a 40-foot high-cube integral reefer. #### SSH Key Pair Generator URL: https://geratools.com/ssh-key-generator Free in-browser SSH key generator. Create Ed25519 or RSA-2048/4096 key pairs with the Web Crypto API, exported as an OpenSSH public key and a PEM private key. Keys are generated locally and never leave your device. How to use: 1. Choose an algorithm: Pick Ed25519 for a modern, compact key or RSA 2048/4096 for maximum compatibility with older servers. 2. Generate the pair: Click Generate. The Web Crypto API creates the key pair in your browser using a cryptographically secure random source. 3. Copy or save the keys: Copy the OpenSSH public key into your server's authorized_keys, and save the PEM private key somewhere safe such as ~/.ssh. FAQ: Q: Are the keys generated securely? A: Yes. The tool uses the browser's Web Crypto (SubtleCrypto) API, which draws from a cryptographically secure random number generator. The same primitive backs HTTPS in your browser, so the entropy quality matches production crypto. Q: Does my private key get uploaded? A: No. Both the public and private key are generated and formatted entirely in your browser. Nothing is sent to any server, so closing the tab is enough to discard them if you change your mind. Q: Which algorithm should I choose? A: Ed25519 is the modern default: small, fast and very secure. Choose RSA only if you must support an older server or device that does not yet accept Ed25519 keys; in that case prefer RSA 4096 over 2048. Q: What format is the public key in? A: The public key is emitted in OpenSSH single-line format (ssh-ed25519 ... or ssh-rsa ...), exactly what you paste into a server's ~/.ssh/authorized_keys file or a Git host's SSH key settings. Q: What format is the private key? A: The private key is exported as PEM (PKCS#8 for RSA, or the raw seed wrapped for Ed25519). Save it with permissions 600. For OpenSSH you may convert it with ssh-keygen -p if a tool expects the legacy key format. #### Typing Speed Reference URL: https://geratools.com/typing-speed-reference Reference benchmarks for typing speed in words per minute by skill level and profession, with a live calculator that derives WPM and accuracy-adjusted net WPM from characters typed and time taken. How to use: 1. Enter your test data: Type the number of characters you typed, the time in seconds, and how many uncorrected errors you made. 2. Read gross and net WPM: The tool computes gross WPM using the standard 5-characters-per-word rule, then subtracts errors to give accuracy-adjusted net WPM. 3. Compare to the benchmarks: Match your net WPM against the skill-level table to see where you fall, from beginner to expert. FAQ: Q: How is words per minute calculated? A: The standard definition treats every 5 characters, including spaces, as one word. Gross WPM is the total characters divided by 5, then divided by the minutes elapsed. This character-based rule makes scores comparable regardless of how long the actual words are. Q: What is the difference between gross and net WPM? A: Gross WPM counts everything you typed. Net WPM penalises mistakes: it subtracts your uncorrected errors from the word count before dividing by time, so net WPM equals gross WPM minus errors per minute. Net WPM is the fairer measure of useful output. Q: What is a good typing speed? A: The average adult types around 40 words per minute. A speed of 60 to 80 WPM is considered fast and is typical of professional typists and developers. Competitive and stenographic typists exceed 100 WPM, and the very fastest sustain well over 120 WPM with high accuracy. Q: Does accuracy matter more than raw speed? A: Usually yes. Each uncorrected error or correction interrupts flow and costs time, so net WPM, which factors in accuracy, predicts real productivity better than raw speed. Most typing tests weight accuracy heavily, and many require at least 95 percent accuracy for a score to count. Q: Why use 5 characters per word instead of real words? A: Real words vary in length, so counting them would make scores depend on the test text rather than the typist. Fixing a word at 5 characters standardises the measure, letting a passage of long technical terms be compared fairly with one of short common words. #### Word Frequency List Generator URL: https://geratools.com/word-frequency-generator Free word frequency list generator that produces a synthetic vocabulary following Zipf's law, with rank, word, frequency, and relative percentage. Ideal for testing search ranking, NLP preprocessing, and text-analysis tools without a real corpus. Runs entirely in your browser. How to use: 1. Set the vocabulary size: Choose how many distinct words you want in the generated frequency list. 2. Tune the Zipf exponent: Adjust the exponent to control how steeply frequency falls off with rank. 3. Read or copy the list: Each row shows rank, a generated word, its modeled frequency, and its share of the total. FAQ: Q: What is Zipf's law? A: Zipf's law observes that in natural language the frequency of a word is inversely proportional to its rank: the most common word appears about twice as often as the second, three times as often as the third, and so on. The exponent controls how sharp that decline is. Q: How is each frequency calculated? A: For a word at rank r the unnormalized weight is 1 divided by r raised to the exponent s. Those weights are then scaled so they sum to the chosen total count, giving integer frequencies. Q: Are the words real? A: No — the words are generated pronounceable tokens so the tool works for any vocabulary size without shipping a dictionary. The distribution of frequencies is what matters for testing ranking and NLP pipelines. Q: What exponent should I use? A: Real English text sits near an exponent of 1.0. Use values above 1 for a steeper, more top-heavy distribution and below 1 for a flatter one. Q: Is anything sent to a server? A: No. The list is computed entirely in your browser with JavaScript, so nothing you generate leaves your device. #### API Key Generator URL: https://geratools.com/api-key-generator Free API key generator. Create cryptographically secure random API keys and tokens with up to 64 bytes of entropy, an optional prefix like sk_live_, and hex, base62 or base64url encoding. Privacy-first — generated entirely in your browser. How to use: 1. Set a prefix: Optionally enter a prefix such as sk_live_ to match your service's key convention. 2. Choose entropy and encoding: Pick how many bytes of entropy (16-64) and whether to encode as hex, base62 or base64url. 3. Generate and copy: Click Generate to get three keys, then copy the first one. FAQ: Q: How secure are the generated keys? A: Keys are built from raw bytes produced by the browser's crypto.getRandomValues CSPRNG. With 32 bytes you get 256 bits of entropy, far beyond what is brute-forceable. Q: Does the encoding change the security? A: No. Hex, base62 and base64url only change how the same underlying random bytes are displayed. Base62 is rejection-sampled per character to avoid bias and preserve full entropy. Q: How many bytes of entropy should an API key have? A: 32 bytes (256 bits) is a strong, common choice and the basis for keys like Stripe's. 16 bytes (128 bits) is the practical minimum for secrets; this tool lets you go up to 64 bytes (512 bits). Q: What does the sk_live_ prefix mean? A: A prefix is a human-readable label that identifies the key's type and environment, such as sk_live_ for a live secret key or pk_test_ for a test publishable key. It carries no entropy itself; it just makes keys easier to recognise and scan for in code. Q: Are the keys sent or logged anywhere? A: No. Generation happens entirely in your browser. Keys are never transmitted or stored, so save them somewhere safe before leaving the page. #### Strong Passphrase Generator URL: https://geratools.com/strong-passphrase-generator Free strong passphrase generator that builds memorable, high-entropy passphrases from random words using your browser's secure crypto API. Choose word count, separators and extras — nothing is uploaded or stored. How to use: 1. Set the word count: Drag the slider to choose how many words your passphrase should contain — more words means more entropy. 2. Pick a separator and extras: Choose a separator and optionally capitalize words or append a number or symbol for sites that require them. 3. Generate and copy: Click Generate, check the estimated entropy, then copy your passphrase straight to the clipboard. FAQ: Q: Why is a passphrase stronger than a password? A: A passphrase of several random words is both easier to remember and harder to crack than a short complex password, because its entropy grows with each word added rather than relying on a few hard-to-recall symbols. Q: How much entropy do the passphrases have? A: The word list holds 260 words, so each word adds about 8 bits of entropy (log2 of 260). Five words give roughly 40 bits, six words about 48 bits, and adding a number or symbol adds a few bits more. Q: Are the words chosen securely? A: Yes. Words are selected with the browser's crypto.getRandomValues secure random generator using rejection sampling to avoid modulo bias — not the predictable Math.random. Q: What is rejection sampling and why does it matter? A: Naively taking a random number modulo the list size slightly favours some words. Rejection sampling discards values in the biased tail and redraws, so every word is exactly equally likely — important for honest entropy. Q: How many words should I use? A: For most accounts four to five words are plenty; for a password-manager master password or disk encryption, use six or more. More words always means more entropy and a harder target. Q: Is my passphrase sent anywhere? A: No. Generation happens entirely in your browser. Nothing is uploaded, logged or stored, so close the tab and it is gone. #### Test Credit Card Number Generator URL: https://geratools.com/test-credit-card-generator Generate fake, Luhn-valid test credit card numbers (Visa, Mastercard, Amex, Discover) with expiry and CVC for payment-form and sandbox testing. Runs entirely in your browser — never real cards. How to use: 1. Choose a card brand: Pick Visa, Mastercard, American Express or Discover — each uses its real test BIN prefixes and length. 2. Set how many to generate: Enter the number of cards you need and click Generate. 3. Copy and use in your sandbox: Copy the tab-separated number, expiry and CVC into your payment-form tests or sandbox. FAQ: Q: Are these real credit card numbers? A: No. They are fictional numbers that merely pass the Luhn checksum and use known brand prefixes, so they satisfy client-side validators. They hold no funds and can never be charged. Q: Why do the numbers pass card validation? A: Every number ends in a correctly computed Luhn check digit and starts with a valid brand prefix, which is exactly what front-end validators look for. Q: Is any data sent anywhere? A: No. All numbers are generated in your browser with a cryptographically secure random generator and nothing is transmitted or stored. Q: What is the Luhn algorithm? A: Luhn (mod 10) is the checksum every card number satisfies. Doubling every second digit from the right, summing the digits, and appending a check digit makes the grand total divisible by 10. It catches most single-digit typos. Q: Can I use these for a real purchase? A: No. They are structurally valid but unissued — no bank account backs them. They are only for exercising form validation, UI states, and sandbox flows that do not hit a real processor. Q: Which brands and lengths are supported? A: Visa (16 digits, CVC 3), Mastercard (16 digits, CVC 3), American Express (15 digits, CVC 4) and Discover (16 digits, CVC 3), each built from that brand's real test prefixes. Q: Should I use these against a payment gateway sandbox? A: For provider sandboxes, prefer the official test cards your gateway documents (such as 4242 4242 4242 4242), since gateways accept a specific allow-list. These generic numbers are best for your own front-end validation tests. Q: Is the randomness secure? A: Yes. The body digits come from crypto.getRandomValues with rejection sampling to avoid modulo bias, then a Luhn check digit is appended. #### Random User Generator URL: https://geratools.com/random-user-generator Generate random fake users — name, username, email, phone, address and date of birth — for test fixtures and mock data. Uses reserved 555 numbers and example.com emails so they reach no one. Runs in your browser. How to use: 1. Set how many users: Enter the number of fake users you need to generate. 2. Generate the list: Click Generate to build complete fictional profiles with name, email, phone, address and date of birth. 3. Copy as JSON: Use the Copy as JSON button to paste the dataset straight into your tests or seed scripts. FAQ: Q: Are these real people? A: No. Every profile is entirely fictional, assembled from built-in name lists. Any resemblance to a real person is coincidental. Q: Can the emails or phone numbers reach anyone? A: No. Emails use example.com domains and phone numbers use the 555 exchange reserved for fiction, so they cannot reach a real inbox or line. Q: What fields does each profile include? A: Each fake user has a full name, a username, an email, a phone number, a street address, and a date of birth — enough to populate a typical user table or signup form for testing. Q: How do I get the data into my tests? A: Click "Copy as JSON" to copy the whole batch as a JSON array, then paste it straight into a seed script, fixture file, or mock API. Each user is an object with the standard fields. Q: Why use 555 phone numbers and example.com emails? A: The 555 exchange and the example.com / example.org domains are reserved by convention for fiction and documentation. Using them guarantees your test data can never accidentally email or call a real person. Q: Is this safe to use under privacy laws like GDPR? A: Because the data is entirely synthetic and matches no real individual, it contains no personal data, making it ideal for demos, screenshots, and shared test environments without privacy concerns. Q: Is any data fetched or uploaded? A: No. Everything is built locally in your browser — no API is called and nothing is transmitted. #### Nginx Config Generator URL: https://geratools.com/nginx-config-generator Free nginx config generator. Pick server name, document root or upstream proxy, SSL, gzip, security headers and rate limiting, then copy or download a ready-to-deploy server block. Runs entirely in your browser. How to use: 1. Enter your server name: Type your primary domain and any additional hostnames (for example www.example.com), separated by spaces. 2. Choose what the server does: Pick static files, a single-page app fallback, or a reverse proxy to a running application, then fill in the document root or upstream URL. 3. Turn on TLS and hardening: Enable SSL, HTTP/2, the HTTP-to-HTTPS redirect, HSTS, gzip, security headers and rate limiting with the toggles. 4. Copy or download the config: The server block updates live. Copy it to your clipboard or download a .conf file ready for sites-available. FAQ: Q: What does this nginx config generator produce? A: It produces a complete server block (and an optional HTTP-to-HTTPS redirect server) covering listen ports, server_name, TLS, gzip, security headers, static caching, rate limiting and your custom location blocks. You can copy it or download it as a .conf file. Q: Where do I put the generated file on my server? A: Save it to /etc/nginx/sites-available/yourdomain.conf, then create a symlink in /etc/nginx/sites-enabled. Run nginx -t to test the syntax and reload with systemctl reload nginx. The generated comments include these paths. Q: Does it handle reverse-proxy setups like Node, Django or a Docker container? A: Yes. Choose reverse proxy mode and enter the upstream URL such as http://127.0.0.1:3000. It adds proxy_pass with the standard Host, X-Real-IP, X-Forwarded-For and X-Forwarded-Proto headers, plus optional WebSocket upgrade headers for real-time apps. Q: How does the rate limiting option work? A: When enabled it emits a limit_req_zone directive as a comment to add to the http block in nginx.conf, then references that zone with limit_req inside your location blocks using a burst that is twice your requests-per-second value. Q: Is the SSL configuration secure by default? A: It restricts protocols to TLS 1.2 and 1.3, prefers strong ECDHE ciphers, enables session caching and can add an HSTS header with preload. You still supply your own certificate and key paths, for example from Let's Encrypt. Q: Is my configuration sent anywhere? A: No. Everything runs in your browser with JavaScript. Your domains, paths and options never leave your machine, and your last configuration is saved only in this browser via localStorage. #### Advanced Password Generator URL: https://geratools.com/advanced-password-generator Free advanced password generator. Choose length and character sets, exclude ambiguous characters, switch to pronounceable or passphrase modes, and watch a live entropy/strength meter. Uses the browser Web Crypto API — nothing is uploaded. How to use: 1. Pick a mode: Choose Random for maximum-entropy strings, Pronounceable for something you can read aloud, or Passphrase for memorable multi-word secrets. 2. Set length and character sets: Drag the length slider and tick the uppercase, lowercase, digit and symbol sets you want. Turn on Exclude ambiguous to drop easily confused characters like I, l, 1, O and 0. 3. Read the strength meter: The live bar shows the estimated entropy in bits, a strength label, and a rough offline crack-time so you know exactly how strong the result is. 4. Copy or save: Copy the password to your clipboard, add it to the session list, or export the whole list as a plain-text file. Everything stays in your browser. FAQ: Q: How random are the passwords? A: Every character is drawn with the browser Web Crypto API (crypto.getRandomValues), the same cryptographically secure random source used for keys and tokens. The tool uses rejection sampling so there is no modulo bias toward any character, and a Fisher-Yates shuffle when guaranteeing one character from each set. Q: What does the entropy figure mean? A: Entropy in bits measures how many equally likely passwords your settings could produce — each extra bit doubles the search space. As a rule of thumb, under 28 bits is very weak, 50 to 72 bits is reasonable, and 100-plus bits is very strong against offline attacks. The meter recalculates instantly as you change length or character sets. Q: What is pronounceable mode for? A: Pronounceable mode alternates consonants and vowels so the result reads like a made-up word you can say aloud and type from memory, then optionally sprinkles in a digit and symbol. It trades a little entropy for memorability, which is useful for passwords you must type often without a manager. Q: Are passphrases actually secure? A: Yes. Four or five random words from a sizeable list reach 50 to 70 bits of entropy, which is stronger than most short symbol-heavy passwords while being far easier to remember. This tool builds passphrases from a curated 300-word list and can add a separator, capitalisation and a trailing number. Q: Should I exclude ambiguous characters? A: Exclude them when a password will be read off a screen, dictated, or typed from a printout — it removes characters like uppercase I, lowercase l, the digit 1, uppercase O and zero that are easy to mix up. For passwords only ever pasted from a manager, leave them in to keep the character pool larger. Q: Is anything sent to a server or stored online? A: No. The generator is 100 percent client-side: passwords are created in your browser and never transmitted. The optional session list and your settings are kept only in this browser local storage, which you can clear at any time with the Clear button. #### Open Graph Preview Generator URL: https://geratools.com/open-graph-preview-generator Free Open Graph preview generator. Fill in og:title, og:description, og:image, and og:url, then see live link-card previews for Facebook/LinkedIn, Twitter large card, Twitter summary card, Slack unfurl, and Discord embed — plus instant HTML meta tag output. 100% client-side. How to use: 1. Enter your page title: Type the og:title value — aim for 60–88 characters so it is not truncated on LinkedIn or Facebook. 2. Add a description: Write a compelling og:description of 120–155 characters. This is the body text shown under the title on most platforms. 3. Set the canonical URL and site name: Paste the full absolute URL (starting with https://) for og:url, and optionally your site name for og:site_name. 4. Paste your image URL: Enter the absolute URL of a 1200x630 pixel JPEG or PNG for og:image. The tool will attempt to load it live inside each card preview. 5. Switch between platform tabs: Click Facebook/LinkedIn, Twitter large card, Twitter small card, Slack, or Discord to see the precise link-card layout for each platform. 6. Copy the generated tags: Click "Copy tags" to copy the ready-to-paste HTML block into your page head. FAQ: Q: What is the correct og:image size? A: 1200x630 pixels at a 1.91:1 aspect ratio is the universal sweet spot. Facebook, LinkedIn, Twitter, and Slack all render it cleanly at that size. Images smaller than 600x315 may be ignored by Facebook. Always host the image at an absolute https:// URL so crawlers can fetch it. Q: Why is my Facebook link preview not updating after I changed the tags? A: Facebook aggressively caches OG data. Visit developers.facebook.com/tools/debug and paste your URL to force a re-scrape. LinkedIn has a similar tool at linkedin.com/post-inspector. Note that caches can take 24 hours to fully expire across their CDN. Q: What is the difference between og:title and the HTML title tag? A: The HTML title tag controls the browser tab and Google search snippets. The og:title property is read by social platforms when someone shares your link. They can (and often should) differ: og:title can be more conversational or punchy, while the HTML title may include your brand name appended. Q: Does Twitter use og:title and og:image or its own twitter:* tags? A: Twitter falls back to og:title, og:description, and og:image if no twitter:* tags are present, but explicit twitter:title and twitter:image give you independent control. This tool generates both sets so you get correct rendering regardless of whether the platform prefers one over the other. Q: What does twitter:card "summary_large_image" versus "summary" mean? A: "summary_large_image" shows a full-width image above the title and description — much more visual and better for CTR on articles, blog posts, and marketing pages. "summary" shows a small square thumbnail to the left of the text, suited to news or compact link formats. Choose summary_large_image unless you have a specific reason to use summary. Q: Does Slack use standard Open Graph tags? A: Yes. Slack reads og:title, og:description, og:image, and og:site_name when it unfurls a URL. For richer Slack integration (buttons, fields, custom branding) you would use the Slack API Block Kit, but for standard link previews OG tags are all that is needed. #### Hreflang Tag Generator URL: https://geratools.com/hreflang-tag-generator Free hreflang tag generator. Build HTML tags, HTTP Link headers, or XML sitemap entries for multilingual and multi-regional SEO. Validates BCP 47 locale codes, adds x-default, and runs entirely in your browser. How to use: 1. Add your locale and URL pairs: For each language or region variant of a page, enter the BCP 47 locale code (e.g. en-GB, fr-FR) and the full canonical URL for that version. 2. Set the x-default fallback: Tick "Add x-default fallback" and enter the URL that should be shown when no language variant matches the visitor — usually your main English or global page. 3. Choose an output format: Pick HTML tags to paste into , HTTP Link header for server config, or XML sitemap format if you cannot modify the HTML directly. 4. Copy or download the output: Click Copy output to paste the tags, or Download file to save as HTML, TXT, or XML ready for deployment. FAQ: Q: What is an hreflang tag and why does it matter for international SEO? A: An hreflang attribute tells Google and Bing which version of a page targets which language or region. Without it, search engines may show users the wrong language variant, or treat near-duplicate translations as duplicate content and split ranking signals. Correct hreflang implementation directs Spanish speakers to your /es/ pages, UK visitors to your /en-GB/ pages, and so on — improving both click-through rates and crawl efficiency. Q: What is x-default and when should I add it? A: x-default is a special hreflang value that designates the fallback URL for users whose language or region has no dedicated variant. Google recommends setting it to your most broadly applicable page — typically your root English page or a language-selector page. Without x-default, Google chooses a fallback arbitrarily, which can result in the wrong variant being served in unmatched markets. Q: What is the correct BCP 47 format for locale codes? A: BCP 47 codes use a two- or three-letter ISO 639-1 language tag followed by an optional ISO 3166-1 alpha-2 country code, separated by a hyphen: language-REGION. Examples: en (English, any region), en-GB (English, United Kingdom), zh-CN (Chinese, Simplified, China), pt-BR (Portuguese, Brazil). Google normalises codes to lowercase language + uppercase region, but the generator enforces the canonical form for you. Q: Does every page need to reference all its language variants, or just some? A: Every language variant must reference all the others, including itself. If your English page references the French page, the French page must also reference the English page (and itself). This bidirectional confirmation is how Google and Bing validate the hreflang cluster. Missing return tags are the most common reason hreflang is ignored by search engines. Q: Which implementation method should I use — HTML, HTTP header, or sitemap? A: HTML tags inside are the easiest for most websites and are supported by all major search engines. HTTP Link headers are the right choice for non-HTML resources like PDFs, or when you want to manage international signals purely at the server layer. XML sitemap entries are best for large sites where modifying every page template is impractical, or when your CMS makes adding per-page tags difficult. All three methods are equally respected by Google; they should not be combined for the same pages. Q: Can I use hreflang for language-only targeting without specifying a country? A: Yes. Using just a language code such as en or es without a country suffix tells Google to show that URL to users of that language regardless of their country. This is useful if you have one English page for all English speakers and separate pages only for specific markets like en-AU or en-CA. Country-less codes cast a wide net; country-specific codes are more precise. You can mix them — use es for your main Spanish content and es-MX specifically for Mexico. ### Formatters & Minifiers #### C/C++ printf Format Specifiers URL: https://geratools.com/c-format-specifiers Reference for C and C++ printf and scanf format specifiers — %d, %u, %x, %f, %e, %g, %s, %c, %p, %%, plus length modifiers (l, ll, h, z, j) and width/precision flags — with the exact argument type each expects. How to use: 1. Search the specifiers: Type a specifier like %zu or a type like unsigned to filter the table. Each row shows the argument type and an example. 2. Add length modifiers: Read the length-modifier section to print sized integers correctly, for example %lld for long long and %zu for size_t. 3. Build width and precision: Combine width and precision such as %8.3f to control field size and decimal places. FAQ: Q: Why must I use %zu for size_t? A: size_t is an unsigned type whose width varies by platform, so printing it with %u or %lu is undefined behaviour on systems where the sizes differ. The z length modifier with u, as in %zu, tells printf the argument is exactly a size_t. Q: What is the difference between %x and %X? A: Both print an unsigned integer in hexadecimal. %x uses lowercase digits a to f, while %X uses uppercase A to F. The alternate flag %#x or %#X adds a 0x or 0X prefix. Q: How do I print a long long? A: Use the ll length modifier: %lld for a signed long long and %llu for unsigned. A single l only covers long, which may be narrower, so passing a long long to %ld is undefined behaviour on many platforms. Q: What does the precision mean for strings versus floats? A: For %s the precision is the maximum number of characters to print, so %.5s prints at most five. For %f the precision is the number of digits after the decimal point, so %.2f prints two. Default float precision is six. Q: Why is passing the wrong type undefined behaviour? A: printf is variadic and reads arguments according to the format string, not the actual types. If the specifier says %d but you pass a double, printf reads the wrong number of bytes and interprets them wrongly, which can crash or print garbage. Compiler warnings catch many of these. #### Coordinate Format Converter URL: https://geratools.com/coordinate-converter Free coordinate converter — enter a latitude/longitude in decimal degrees, DMS, or DDM and instantly see it in UTM, MGRS-style grid, and Geohash. Uses standard WGS84 formulas client-side; no coordinates leave your browser. How to use: 1. Enter a position: Type latitude and longitude as decimal degrees, or paste a DMS or DDM string into the parser. 2. Read every format: The tool shows the same point in decimal degrees, DMS, DDM, UTM, and Geohash at once. 3. Copy what you need: Each output row has its own value you can select and copy into your map or GIS tool. FAQ: Q: What datum does this use? A: All conversions assume the WGS84 ellipsoid (the GPS standard) used by Google Maps, OpenStreetMap, and modern GNSS receivers. Older national datums such as OSGB36 or NAD27 will be offset by tens of metres and are not converted here. Q: How accurate is the UTM conversion? A: It uses the standard Karney/USGS series expansion, which is accurate to well under a millimetre within a zone's valid range. Points far outside their natural zone or beyond 84°N/80°S are outside UTM's defined area. Q: What is a Geohash? A: A Geohash encodes a latitude/longitude into a short string by repeatedly bisecting the world into halves. Each extra character roughly quintuples precision: 6 characters is about 1.2 km, 8 is about 38 m, and 9 is about 5 m. Q: How do I type DMS coordinates? A: Use degrees, minutes, seconds with a hemisphere letter, for example 40°10'37.9"N 44°30'52.3"E. The parser also accepts plain spaces or hyphens between the parts and a leading minus sign instead of a hemisphere. Q: Are my coordinates sent to a server? A: No. Every formula runs locally in your browser, so the locations you enter stay completely private. #### IMO Number Format Reference URL: https://geratools.com/imo-number-format-reference Reference and live validator for IMO ship numbers: 7 digits with a check digit derived from the first six. See the weighting algorithm, verify any number, and learn how IMO numbers are assigned. How to use: 1. Enter the IMO number: Type the 7-digit IMO number, with or without the "IMO" prefix. Spaces and dashes are ignored. 2. Read the validity result: The tool computes the check digit and tells you immediately whether the number is valid. 3. Inspect the working: The breakdown table shows each digit, its weight, and the product so you can follow the algorithm yourself. FAQ: Q: What is an IMO number? A: An IMO number is a unique 7-digit identifier assigned to a merchant ship's hull by the International Maritime Organization. It stays the same for the ship's entire life, even if it is sold, re-flagged, or renamed. Q: How is the IMO check digit calculated? A: Multiply the first six digits by the weights 7, 6, 5, 4, 3, 2 respectively, then sum the products. The check digit is the units digit (the rightmost digit) of that sum. Q: Does the "IMO" prefix count as part of the number? A: No. The prefix is just a label. Only the 7 digits matter, and the validator strips the prefix automatically before checking. Q: Do all ships have an IMO number? A: Most seagoing merchant ships of 100 gross tonnage and above carry one. Some vessels such as fishing boats below a size threshold, warships, and pleasure yachts are exempt, though many obtain one voluntarily. Q: Is an MMSI number the same as an IMO number? A: No. An MMSI is a 9-digit radio identifier that can change if the ship changes flag, while the IMO number is a permanent 7-digit hull identifier that never changes. #### International Date Format Reference URL: https://geratools.com/international-date-format-reference Look up the everyday date notation used in countries worldwide, DMY, MDY, or YMD, with each shown as a sample date and the unambiguous ISO 8601 equivalent. Search and filter to avoid 03/07 vs 07/03 confusion. Runs in your browser. How to use: 1. Search a country: Type a country name to see which date order it uses in everyday civil writing. 2. Filter by order: Narrow the list to DMY, MDY, or YMD to see every country sharing a convention. 3. Read the sample: Each country shows the same date (7 March 2026) in its local order plus the ISO 8601 equivalent. FAQ: Q: Which date order is most common worldwide? A: Day-Month-Year (DMY) is by far the most widespread, used across most of Europe, Africa, South America, Oceania, and much of Asia. Month-Day-Year (MDY) is mainly a United States convention, while Year-Month-Day (YMD) dominates East Asia. Q: Why is 03/07/2026 ambiguous? A: In the United States 03/07/2026 reads as 7 March because of the MDY order, but almost everywhere else it reads as 3 July under DMY. With no context the slashed numeric form is genuinely ambiguous, which causes real errors in contracts, software, and travel. Q: What is ISO 8601 and why use it? A: ISO 8601 writes dates as YYYY-MM-DD, largest unit to smallest. It is unambiguous across every locale and sorts correctly when treated as plain text, so it is the recommended format for databases, filenames, logs, and any cross-border document. Q: Does a country only ever use one format? A: No. Usage varies by register and context. Canada, for example, officially favours ISO YMD but sees DMY and MDY in daily life, and many countries use ISO 8601 in technical settings even when DMY dominates casual writing. This tool lists the dominant everyday civil order. Q: How does the YMD order help sorting? A: Because YMD lists the year first, then month, then day, dates in that format sort chronologically when compared as ordinary strings. A list of YYYY-MM-DD dates sorts the same alphabetically and by time, which is why ISO 8601 is ideal for filenames and logs. #### ISO 8601 Date/Time Format Reference URL: https://geratools.com/iso-8601-format-reference Reference for ISO 8601 date and time representations: calendar, ordinal and week dates, times with timezone offsets, durations (PnYnMnD) and intervals, in both basic and extended forms with worked examples. How to use: 1. Pick a category: Filter between dates, times, durations and intervals to see only the formats you need. 2. Compare basic vs extended: Each entry shows the basic (no separators) and extended (with hyphens/colons) forms side by side. 3. Read the live example: Examples use a fixed sample instant so you can map each format to a concrete value. FAQ: Q: What is the difference between basic and extended ISO 8601 format? A: Extended format uses separators (2026-06-11, 14:30:00), while basic format omits them (20260611, 143000). Both encode the same value; extended is more human-readable and is what most APIs and RFC 3339 use. Q: How does ISO 8601 represent a duration? A: Durations start with P, then date components nYnMnD, then T before time components nHnMnS. For example P1Y2M10DT2H30M is 1 year, 2 months, 10 days, 2 hours and 30 minutes. P0D is a zero duration. Q: What is an ISO 8601 week date? A: A week date is written YYYY-Www-D, e.g. 2026-W24-4 for Thursday of ISO week 24. Weeks start on Monday (D=1) and week 1 is the week containing the year's first Thursday, so it can begin in late December. Q: How are timezone offsets written in ISO 8601? A: A trailing Z means UTC, while +hh:mm or -hh:mm gives an offset, e.g. 14:30:00+02:00. Omitting the designator means local time with no offset information, which APIs should generally avoid. Q: What is an ISO 8601 ordinal date? A: An ordinal date is YYYY-DDD where DDD is the day of the year from 001 to 365 (or 366 in leap years). For example 2026-162 is the 162nd day of 2026, which is 2026-06-11. #### JavaScript Formatter / Beautifier URL: https://geratools.com/js-formatter Free JavaScript formatter and beautifier — re-indent minified or messy code around braces and statements with 2-space, 4-space, or tab indentation. Strings, regex, and comments are preserved. Runs in your browser; nothing is uploaded. How to use: 1. Choose indentation: Pick 2 spaces, 4 spaces, or tabs to match your project's style. 2. Paste the code: Drop in minified or badly formatted JavaScript and the beautifier reformats it instantly. 3. Copy the result: Click Copy to grab the cleanly indented code. FAQ: Q: What does the beautifier do? A: It re-indents your code based on brace depth and adds newlines after braces and semicolons, turning a single dense line into a readable, consistently indented block. You choose 2 spaces, 4 spaces, or tabs. Q: Does it change my strings or regular expressions? A: No. The formatter tokenizes the source so that strings, template literals, regular-expression literals, and comments are treated as opaque units. Their contents are copied verbatim, so a brace or semicolon inside a string never affects indentation. Q: Is this the same as Prettier? A: It applies clean, deterministic indentation but does not reflow long lines to a maximum width or normalise quote style the way Prettier does. It is ideal for making minified or pasted code readable quickly, without installing anything. Q: Can it format minified bundles? A: Yes. Paste a minified one-liner and it will expand braces, statements, and blocks into properly indented code so you can read and debug it. Combine it with our JavaScript minifier to go the other direction. Q: Is my code uploaded anywhere? A: No. All formatting happens in your browser using JavaScript. Your source code never leaves your device, so it is safe for private or unreleased work. #### Nginx Config Formatter URL: https://geratools.com/nginx-config-formatter Indents Nginx config blocks consistently by brace depth and highlights common misconfigurations such as missing semicolons and unclosed braces using a pure-JS tokenizer. No config is sent to any server. How to use: 1. Paste your config: Drop your nginx.conf or a server/location block into the text area. A sample loads by default so you can see the formatter in action. 2. Pick an indent size: Choose 2, 4, or 8 spaces. The tool re-indents every line based on its brace-nesting depth. 3. Read the validation panel: Review the formatted output and the list of issues, such as missing semicolons or unbalanced braces, then copy the result. FAQ: Q: Does this tool fully validate Nginx syntax? A: No. It is a syntax-level formatter that checks brace balance and statement termination. It cannot confirm that a directive is valid in its context, so always run nginx -t before reloading. Q: How does it detect a missing semicolon? A: The tokenizer walks each line respecting quotes and comments. If directive text remains after a line ends without a semicolon or brace, it flags that line as a likely missing semicolon. Q: Is my configuration uploaded anywhere? A: No. The entire tokenizer and formatter run in your browser using JavaScript. Your config never leaves your device, so it is safe to format files containing internal hostnames or paths. Q: Why did my closing brace get flagged? A: A stray closing brace means the formatter saw a } with no matching open block at that point. This usually indicates a deleted opening brace or an extra } earlier in the file. Q: Can it handle inline comments? A: Yes. The tokenizer only treats a hash as a comment when it appears outside quotes, so a # inside a quoted string or regex is preserved rather than stripped as a comment. #### OpenMetrics Exposition Format URL: https://geratools.com/openmetrics-format Reference for the OpenMetrics text exposition format including TYPE, HELP, UNIT lines, metric suffixes, label syntax and the EOF terminator. Understand the standard that succeeds Prometheus text format. How to use: 1. Search the format elements: Type a keyword like TYPE, EOF, bucket, or exemplar to filter the exposition syntax reference. 2. Filter by group: Use the group dropdown to view Metadata, Sample, Histogram, Exemplar, Labels, or Transport elements. 3. Build a valid exposition: Combine the metadata, sample, and EOF lines following the shown syntax to produce a parseable OpenMetrics payload. FAQ: Q: How does OpenMetrics differ from the Prometheus text format? A: OpenMetrics is a standardized superset based on the Prometheus text format. Key additions are the mandatory # EOF terminator, a # UNIT metadata line, the _total suffix requirement for counters, and native support for exemplars and the Info and StateSet metric types. Q: What is the # EOF line for? A: OpenMetrics requires every exposition to end with a line containing exactly # EOF. This lets a parser know it received the complete payload and was not truncated mid-stream, which the older Prometheus format could not guarantee. Q: What metadata lines can a metric have? A: Each metric family can declare # HELP for a description, # TYPE for the metric type such as counter or gauge, and # UNIT for the base unit. The UNIT must match the suffix on the metric name, for example a unit of seconds with a metric ending in _seconds. Q: What is an exemplar in OpenMetrics? A: An exemplar links a sample to a trace by appending a hash followed by labels and an optional value and timestamp, for example after a histogram bucket value. It lets observability tools jump from a metric data point straight to a representative trace. Q: What suffixes does a counter use in OpenMetrics? A: An OpenMetrics counter named x must expose its value as x_total. It may also expose an optional x_created line giving the Unix timestamp when the counter was first initialized, which helps detect resets. #### PEM Private Key Format Validator URL: https://geratools.com/private-key-validator Parses a pasted PEM-encoded private key (RSA, EC or Ed25519) locally to report its key type, label, encoding and structural validity. The key never leaves your browser. Useful for developers debugging TLS certificate and SSH key configuration issues offline. How to use: 1. Paste the PEM key: Paste your private key including the BEGIN and END lines. Both PKCS#8 and PKCS#1/SEC1 labels are recognised. 2. Read the parsed result: The tool decodes the Base64 body, reads the PEM label and ASN.1 algorithm identifier, and reports the key type. 3. Fix any format error: If the key is malformed, the tool tells you whether the label, Base64 or DER structure is the problem. FAQ: Q: Is my private key sent anywhere? A: No. The PEM is Base64-decoded and parsed in your browser's JavaScript; the bytes never touch a network. Even so, treat private keys as secrets and avoid pasting production keys into any tool. Q: Which key formats are supported? A: It recognises PKCS#8 (BEGIN PRIVATE KEY), PKCS#1 RSA (BEGIN RSA PRIVATE KEY), SEC1 EC (BEGIN EC PRIVATE KEY) and Ed25519 keys wrapped in PKCS#8. Encrypted keys (BEGIN ENCRYPTED PRIVATE KEY) are detected but not decrypted. Q: How does it tell RSA from EC from Ed25519? A: For PKCS#8 it reads the ASN.1 AlgorithmIdentifier OID inside the DER: 1.2.840.113549.1.1.1 is RSA, 1.2.840.10045.2.1 is EC, and 1.3.101.112 is Ed25519. The PKCS#1 and SEC1 labels themselves also imply the type. Q: Does a valid format mean the key is usable? A: It confirms the structure parses correctly, which catches the most common copy-paste and encoding errors. It does not verify the key against a certificate or test a cryptographic operation. Q: Why does my key fail with an invalid Base64 error? A: Usually the BEGIN/END lines are missing, the body has stray characters, or line breaks were mangled. Re-copy the whole block including both armour lines and ensure no extra spaces were added. #### strftime Format Reference URL: https://geratools.com/strftime-format-reference Reference for strftime format codes: each %-directive's meaning and a live example rendered from a sample date, with notes on POSIX standard codes versus GNU and language-specific extensions. How to use: 1. Search a directive: Type a code like "%Y" or a word like "weekday" to filter the directive table. 2. Filter by group: Switch between date, time, zone and composite directives to find the code you need. 3. Read the live example: Each row shows real output rendered from a fixed sample timestamp so the meaning is concrete. FAQ: Q: What is the difference between %Y and %y in strftime? A: %Y is the full four-digit year (2026), while %y is the last two digits zero-padded (26). Use %Y to avoid century ambiguity; %y is mainly for compact legacy formats. Q: What does %j produce in strftime? A: %j is the day of the year as a zero-padded three-digit number from 001 to 366. For example 11 June 2026 is %j = 162. It mirrors the ISO 8601 ordinal day. Q: Which strftime codes are POSIX standard versus extensions? A: Codes like %Y, %m, %d, %H, %M, %S, %p, %A, %B and %Z are POSIX standard and portable. Codes like %-d (no padding) or %s (Unix epoch) are GNU or platform extensions and may not work everywhere. Q: What is the difference between %H and %I? A: %H is the hour on a 24-hour clock (00-23), while %I is the hour on a 12-hour clock (01-12). %I is normally paired with %p (AM/PM) to be unambiguous. Q: Does strftime work the same in Python, Ruby and PHP? A: The common POSIX codes behave the same, but PHP's date() uses a different letter scheme entirely (PHP's strftime is deprecated). Python and Ruby share most C codes, though Ruby adds extras like %L for milliseconds. #### SWIFT/BIC Format by Country URL: https://geratools.com/swift-bic-format-by-country Reference the SWIFT/BIC code structure by country: 8 or 11 characters, the 2-letter country code position, branch code, and sample codes. Validate format and learn what each section means. Runs in your browser. How to use: 1. Pick or type a country: Choose a country from the list, or type any 8 or 11 character SWIFT/BIC code into the validator box. 2. Read the structure breakdown: The tool splits the code into bank code, country code, location code, and optional branch and confirms each part against the ISO 9362 rules. 3. Check validity: The validator flags wrong length, invalid characters, or a country-code mismatch and explains exactly which part is off. FAQ: Q: What is the difference between a SWIFT code and a BIC? A: They are the same thing. BIC (Business Identifier Code) is the ISO 9362 name for the code; SWIFT is the network that issues and routes them. Banks and forms use the terms interchangeably. Q: Why are some SWIFT codes 8 characters and others 11? A: An 8-character code identifies a bank's head office. Adding a 3-character branch code makes it 11 and points to a specific branch. An 8-character code is treated as the primary office, often written with XXX appended to make 11. Q: What does each part of the code mean? A: Characters 1-4 are the bank code (letters), 5-6 are the ISO 3166 country code, 7-8 are the location code, and 9-11 are the optional branch code. For example DEUTDEFF500 is Deutsche Bank, Germany, Frankfurt, branch 500. Q: How do I validate a SWIFT code's country? A: Characters 5 and 6 must match a real ISO 3166-1 alpha-2 country code. If you paste a German bank code it must contain DE in positions 5-6. A mismatch means the code is malformed or for a different country. Q: Does a valid format guarantee the bank exists? A: No. This tool checks structure only: length, allowed characters, and a valid country code. Confirming a working bank requires the official SWIFT directory, because well-formed codes can still be unassigned. #### Coordinate Formatter (Multi-format) URL: https://geratools.com/w3w-coordinate-formatter Enter one latitude and longitude and see it formatted as decimal degrees, DMS, degrees decimal minutes, UTM, MGRS, and Geohash at once. Correct WGS84 projections computed in your browser, no server. How to use: 1. Enter a coordinate: Type a latitude and longitude in decimal degrees, with south and west as negative values. 2. Read every format: The tool instantly renders the same point as DMS, DDM, UTM, MGRS, and Geohash. 3. Copy what you need: Use the value that matches your map, GPS, or military grid reference system. FAQ: Q: Which coordinate systems are shown? A: Decimal degrees (DD), degrees-minutes-seconds (DMS), degrees decimal minutes (DDM), Universal Transverse Mercator (UTM), Military Grid Reference System (MGRS), and Geohash. All are computed from the same WGS84 latitude and longitude. Q: How is UTM calculated? A: The tool projects the WGS84 coordinate onto the Transverse Mercator using the standard series expansion, picking the 6-degree-wide zone from the longitude. It outputs the zone number, hemisphere band, and easting and northing in metres. Q: What is MGRS and how does it relate to UTM? A: MGRS is a grid reference built on top of UTM. It adds a 100,000-metre square letter pair to the zone and band, then truncates the easting and northing to a chosen precision. This tool gives a 1-metre, 10-digit MGRS string. Q: What is a Geohash? A: A Geohash encodes a latitude and longitude into a short base-32 string by repeatedly bisecting the world into halves. Longer strings mean smaller, more precise cells. It is widely used for spatial indexing and proximity searches. Q: Are UTM and MGRS valid everywhere? A: UTM and MGRS cover latitudes from 80 degrees south to 84 degrees north. Outside that band the polar regions use UPS instead, which this tool does not compute, so extreme polar coordinates will be flagged. #### HTML Formatter & Minifier URL: https://geratools.com/html-formatter Free online HTML formatter. Pretty-print messy markup with 2-space, 4-space or tab indentation, or minify it. Void elements and pre/script/style content are preserved. Privacy-first. How to use: 1. Paste your HTML: Drop your markup or fragment into the input box. 2. Choose an indent and format: Pick 2 spaces, 4 spaces or tab, then click Format to indent by nesting depth or Minify to strip whitespace and comments. 3. Copy the result: Click Copy to put the formatted markup on your clipboard. FAQ: Q: Is my HTML uploaded anywhere? A: No. The formatter runs entirely in your browser using JavaScript. Your markup is never sent to a server, which is why it keeps working offline once the page has loaded. Q: How accurate is the formatting? A: The tool indents by tag nesting depth and knows which elements are void (img, br, input, meta and so on) so they never wrongly increase indentation. The contents of pre, script, style and textarea are kept verbatim. It re-lays-out the markup but does not validate it, so it will not flag invalid HTML. Q: Will it break my page or scripts? A: No. Only whitespace between tags changes when formatting. Attribute values, text and the raw contents of pre, script, style and textarea are preserved exactly so behaviour is unchanged. Q: What indentation options are there? A: You can choose 2 spaces, 4 spaces, or a tab character per nesting level. Pick whichever matches your project style guide. Q: What is a void element? A: A void element has no closing tag and no children — img, br, input, meta, link, hr, and a few others. The formatter knows these never open a new indentation level, so following lines stay correctly aligned. Q: Does it validate my HTML? A: No. It re-lays out the markup for readability but does not check for errors, so malformed HTML is reformatted as-is rather than flagged. Use a validator for correctness checks. #### JavaScript Minifier URL: https://geratools.com/javascript-minifier Free JavaScript minifier — remove comments and collapse whitespace to shrink .js files. Strings, template literals and regex are preserved. Runs entirely in your browser, nothing is uploaded. How to use: 1. Paste your JavaScript: Drop your .js source into the input box. 2. Click Minify: Comments and unnecessary whitespace are stripped while strings and regex stay intact. 3. Copy the result: Copy the minified output and see how many characters you saved. FAQ: Q: Does it rename variables or mangle names? A: No. This is a safe "obvious wins" minifier — it removes comments and collapses whitespace but never renames identifiers or rewrites your code, so valid input stays valid. Q: Are strings and regular expressions kept intact? A: Yes. The minifier tracks string literals, template literals and regular-expression literals and copies their contents verbatim, so a comment marker or space inside a string is never touched. Q: How does it tell a regex apart from a division sign? A: It checks the previous meaningful token. A slash starts a regex only when the prior token cannot end an expression — after operators, brackets, commas, or keywords like return, typeof and in — otherwise the slash is treated as division. Q: How much smaller will my file be? A: It depends on how heavily commented and indented your source is. The tool reports the exact character count and the percentage saved after each run. Comment-heavy, deeply indented code shrinks the most; already-dense code shrinks little. Q: Will it break minified code if I run it twice? A: No. Running it on already-minified code is safe and roughly idempotent — there is little whitespace left to remove, so the output stays valid. Q: Should I use this for production builds? A: It is great for quick inline snippets, email size limits and pasting compact code. For production bundles a full tool like Terser or esbuild also renames variables and does AST-level optimisations, achieving smaller output than whitespace removal alone. Q: Is my code uploaded anywhere? A: No — minification runs entirely in your browser. Nothing is sent to a server, which makes it safe for proprietary code. ### Reference & Cheatsheets #### Regex Tester with Plain-English Explainer URL: https://geratools.com/regex-tester Free regex tester with live match highlighting and a plain-English explainer. Test JavaScript regular expressions against your text, toggle flags, and understand what each part does. How to use: 1. Enter a pattern: Type your regular expression and toggle the flags you need. 2. Add test text: Paste the text to test against. Matches are highlighted live. 3. Read the explanation: See a step-by-step plain-English breakdown of what the pattern does. FAQ: Q: Which regex flavor is supported? A: JavaScript regular expressions (the same engine your browser uses via the native RegExp object), including the g, i, m and s flags. Patterns valid in JS are valid here. Q: Does the explainer cover everything? A: It explains the common metacharacters, character classes, quantifiers, anchors and groups token by token. It is a learning aid, not a full formal parser, so very exotic constructs may be summarised rather than fully decomposed. Q: Is my text private? A: Yes. Everything runs in your browser — your pattern and test text are never sent anywhere. Q: What do the g, i, m and s flags do? A: g (global) finds every match instead of just the first; i (ignore case) makes the match case-insensitive; m (multiline) makes ^ and $ match at line breaks; s (dotall) lets the dot . also match newline characters. Q: Why are only the first matches highlighted without the g flag? A: For highlighting, the tester always forces the global flag internally so you can see every match. In real code, a regex without g stops after the first match — so remember to add g when you need all matches. Q: How do I match a literal special character like a dot or bracket? A: Escape it with a backslash. Use \\. for a literal full stop, \\( for a literal parenthesis, and \\\\ for a literal backslash. Unescaped, those characters have special meaning. Q: What is the difference between greedy and lazy quantifiers? A: Greedy quantifiers like .* match as much as possible; adding a ? makes them lazy (.*?) so they match as little as possible. Lazy quantifiers are the fix when .* swallows too much text. #### Regex Builder & Tester URL: https://geratools.com/regex-builder Free online regex builder and tester. Edit a pattern and flags, see live match highlighting on your test text, inspect capture groups in a table, run replacements, and load common-pattern presets. 100% in-browser — nothing is uploaded. How to use: 1. Type or pick a pattern: Enter a regular expression in the pattern box, or click a preset like Email address or IPv4 to load a working example. 2. Choose your flags: Toggle g (global), i (ignore case), m (multiline), s (dotall), u (unicode) or y (sticky) to control how the pattern matches. 3. Paste your test string: Drop the text you want to search into the test box and watch every match highlight in real time as you type. 4. Inspect the capture groups: The results table lists each match with its position, full text and the value of every numbered and named capture group. 5. Try a replacement: Open the Replace panel and use $1, $2 or named references to preview a find-and-replace before you run it in your code. FAQ: Q: What regex engine does this tester use? A: It runs your pattern through the browser's built-in JavaScript RegExp engine — the same one used by Node.js and every modern browser. Results match what you will see in JavaScript and TypeScript exactly, including support for named groups, lookbehind and unicode property escapes in current browsers. Q: What do the flags g, i, m, s, u and y mean? A: g finds every match instead of just the first; i makes matching case-insensitive; m lets ^ and $ match at line breaks; s (dotall) lets the dot match newlines; u enables full unicode handling; and y (sticky) matches only from the current position. Hover any flag button for a one-line reminder. Q: How do capture groups appear in the results? A: Every parenthesised group becomes a column in the match table. Numbered groups show as $1, $2 and so on, while named groups written as (?...) show under a column. Non-capturing groups (?:...) and lookarounds are excluded from the count, just as they are in JavaScript. Q: Can I use this to find and replace text? A: Yes. Open the Replace panel and type a replacement string. You can reference captured groups with $1, $2 or $, and the tool previews the fully replaced text instantly so you can verify the result before pasting it back into your editor. Q: Is my pattern and test data sent anywhere? A: No. Everything runs locally in your browser using native JavaScript. Your pattern, flags and test string are never uploaded to a server. The tool also remembers your last session in this browser's local storage so you can pick up where you left off. Q: Why might my pattern match differently in another language? A: Regex syntax varies between engines. JavaScript differs from PCRE (PHP, Perl), Python's re module and .NET in areas like lookbehind support, possessive quantifiers and named-group syntax. This tester reflects JavaScript behaviour, so double-check engine-specific features such as \\K, atomic groups or POSIX classes if you are targeting another language. #### HTTP Accept Headers Reference URL: https://geratools.com/accept-header-reference Reference for HTTP content-negotiation Accept-family headers with q-factor weighting, wildcard rules and a live q-value preference parser for any Accept header string. How to use: 1. Read the header families: Review what Accept, Accept-Encoding, Accept-Language and Accept-Charset each negotiate and their default behaviour. 2. Paste a header to parse: Enter any Accept-style header and the parser sorts each value by its q-factor from most to least preferred. 3. Apply the wildcard rules: Use the precedence notes to predict which value a server selects when wildcards and q-values overlap. FAQ: Q: What is a q-value? A: A q-value (quality factor) is a weight from 0 to 1 attached to a value with ;q=, expressing relative preference. q=1 is the default and most preferred; q=0 explicitly rejects a value. Servers pick the acceptable option with the highest q. Q: How are wildcards ranked against specific types? A: More specific values win ties: text/html beats text/* which beats */*. When q-values differ the higher q wins regardless of specificity, so text/plain;q=0.9 is preferred over text/html;q=0.8. Q: What does Accept-Encoding negotiate? A: It lists the content-codings the client can decode, such as gzip, br (Brotli), deflate and zstd. identity means no encoding. The server compresses with the highest-q supported coding and echoes its choice in Content-Encoding. Q: Is Accept-Charset still used? A: Largely deprecated. Modern clients omit it because UTF-8 is assumed everywhere, and most browsers no longer send it. It is included here for completeness and legacy systems. Q: Does this tool send my header anywhere? A: No. Parsing happens entirely in your browser with JavaScript. Nothing is uploaded, logged or stored. #### Age of Consent by Country Reference URL: https://geratools.com/age-of-consent-reference Searchable reference of the legal age of sexual consent across countries, with notes on close-in-age provisions, recent reforms, and within-country variation. General legal orientation, not legal advice. How to use: 1. Search a country: Type a country name to filter the table down to that jurisdiction. 2. Sort the list: Switch between alphabetical order and sorting by the lowest legal age to compare countries. 3. Read the notes: The notes column flags close-in-age defences, recent law changes, and where the age varies within a country. FAQ: Q: What is the age of consent? A: The age of consent is the minimum age at which a person is legally considered able to agree to sexual activity. Sexual activity with someone below it is a criminal offence regardless of apparent willingness, often charged as statutory rape. Q: Why does it vary so much between countries? A: Each country sets its own age through national law, shaped by legal tradition, religion, and social policy. The general age ranges from 14 in much of continental Europe to 16 in the UK and 18 in several countries. Q: What is a close-in-age exemption? A: A close-in-age (or Romeo and Juliet) provision allows consensual activity between two young people whose ages are near each other, even if one is below the general age of consent. It prevents prosecuting peers while still protecting minors from adults. Q: Can the age differ inside one country? A: Yes. In federations like the United States, Australia, and Mexico, the age is set at the state or territory level, so it can differ within the same country. The table notes the most common baseline and key exceptions. Q: Is this table legal advice? A: No. It is a simplified general reference. Real laws are complex, account for the type of act, relationships of authority, and frequent reforms. Always consult current statutes or a qualified lawyer for any legal matter. #### Agile Ceremony Reference URL: https://geratools.com/agile-ceremony-reference Reference for the Scrum ceremonies — sprint planning, daily standup, review and retrospective — with Scrum Guide timeboxes, participants and purpose, plus a live timebox scaler for your sprint length. How to use: 1. Set your sprint length: Pick how many weeks your sprint runs; the recommended timeboxes scale to match. 2. Read each ceremony: See the cadence, participants and purpose of every Scrum event from planning to retrospective. 3. Use the timeboxes: Treat the lengths as maximums — end an event early once its goal is achieved. FAQ: Q: What are the four main Scrum ceremonies? A: Sprint Planning starts the sprint by setting a goal and selecting work. The Daily Scrum is a 15-minute daily sync. The Sprint Review inspects the increment with stakeholders. The Sprint Retrospective reflects on how to improve. Backlog refinement is ongoing rather than a fixed event. Q: How long should each ceremony last? A: The Scrum Guide gives maximums for a one-month sprint: Sprint Planning up to 8 hours, Sprint Review up to 4, Retrospective up to 3, and the Daily Scrum fixed at 15 minutes. Shorter sprints get proportionally shorter events, except the Daily Scrum which stays at 15 minutes. Q: Why does the Daily Scrum stay 15 minutes for any sprint length? A: The Daily Scrum is a daily cadence tied to a single day of work, not to the sprint length. Whether your sprint is one week or four, the team still meets once a day for at most 15 minutes to inspect progress and re-plan the day. Q: Is backlog refinement a ceremony? A: Not formally. Refinement is an ongoing activity in which the Product Owner and Developers add detail, estimates and order to backlog items so they are ready for future sprints. Teams typically spend around 10% of their capacity on it across the sprint. Q: Does this tool send my sprint settings anywhere? A: No. The timeboxes are scaled entirely in your browser. Nothing is uploaded, logged or stored. #### Aircraft Wake Turbulence Category Reference URL: https://geratools.com/aircraft-wake-turbulence-category Reference for ICAO aircraft wake turbulence categories with Maximum Take-Off Weight ranges and example aircraft, plus a lookup that classifies any aircraft as Light, Medium, Heavy, or Super from its MTOW in kilograms. How to use: 1. Find a category: Enter an aircraft's certified Maximum Take-Off Weight in kilograms to see which ICAO wake category it falls into. 2. Read the band: The tool returns the single-letter code and name and highlights the matching row in the reference table. 3. Check examples: Scan the table for typical aircraft in each band to sanity-check your classification. FAQ: Q: What are the ICAO wake turbulence categories? A: ICAO defines four categories by Maximum Take-Off Weight: Light up to 7,000 kg, Medium from 7,000 to 136,000 kg, Heavy at 136,000 kg or more, and Super for the very largest designated aircraft such as the Airbus A380. Heavier aircraft shed stronger wingtip vortices. Q: Why does wake turbulence category matter? A: It sets the minimum separation a following aircraft must keep behind a leading one. A lighter aircraft trailing a heavier one needs more spacing because it is most vulnerable to the leader's vortices, which can roll or pitch it dangerously near the ground. Q: Which aircraft are classed as Super? A: Only the Airbus A380-800 and the Antonov An-225 Mriya are in the Super category. The word Super is spoken in the radio callsign so controllers and other pilots apply the largest wake separation behind them. Q: Is the category based on actual take-off weight? A: No. The wake category uses the aircraft's certified Maximum Take-Off Weight, not the weight on a given flight. This keeps a type's category fixed regardless of how much fuel or payload it carries on any particular departure. Q: How does this relate to the FAA RECAT scheme? A: The FAA RECAT (Wake Turbulence Re-categorisation) refines the classic four ICAO bands into more groups, A through F or I, to allow tighter but still safe separation. The ICAO Light/Medium/Heavy/Super bands shown here remain the values quoted on flight plans and in ATC callsigns. #### Altitude & Oxygen Level Reference URL: https://geratools.com/altitude-oxygen-reference Enter any altitude in metres or feet and see the atmospheric pressure and effective sea-level-equivalent oxygen percentage, computed from the International Standard Atmosphere model, plus a table from sea level to Everest. Runs in your browser. How to use: 1. Choose units: Select metres or feet for the altitude you want to evaluate. 2. Enter the altitude: Type a height and the tool computes barometric pressure and effective oxygen instantly. 3. Compare to the table: Check your value against the reference altitudes from sea level to the summit of Everest. FAQ: Q: Does the oxygen percentage of air actually change with altitude? A: No. Dry air is about 20.9% oxygen by volume at every altitude. What falls is the total air pressure, which lowers the partial pressure of oxygen, the figure your lungs actually respond to. Effective oxygen restates that fall as a sea-level percentage. Q: What is effective oxygen? A: Effective oxygen is the oxygen percentage that, at sea-level pressure, would give the same oxygen partial pressure you experience at altitude. At 3000 m the air is still 20.9% oxygen, but the thinner air makes it feel like roughly 14.5% at sea level. Q: How is atmospheric pressure calculated? A: The tool uses the barometric formula from the International Standard Atmosphere for the troposphere. Pressure equals 101325 Pa times (1 minus a lapse-rate term) raised to the power of about 5.255. It is accurate up to roughly 11000 metres. Q: At what altitude does altitude sickness start? A: Acute mountain sickness risk generally begins above about 2500 to 3000 metres, where effective oxygen drops below roughly 15%. Severity rises with height and ascent speed. The death zone above 8000 metres has too little oxygen to sustain human life for long. Q: Why does the model stop being accurate above 11000 m? A: The simple barometric formula assumes a constant temperature lapse rate that only holds in the troposphere, up to about 11000 metres. Above the tropopause the atmosphere behaves differently, so the tool flags figures there as extrapolated and approximate. #### APA 7th Edition Citation Reference URL: https://geratools.com/apa7-citation-reference Reference table of APA 7th edition reference-list formats for books, journal articles, webpages, reports, videos and datasets, with worked examples and copyable templates plus in-text citation rules. #### ASCII Table URL: https://geratools.com/ascii-table Full 7-bit ASCII table (0-127) plus extended 128-255, filterable by value or character type. See decimal, hex, octal and binary for every code point with control-character names. How to use: 1. Search a value or character: Type a decimal number, two-digit hex, or a character to jump straight to its row. 2. Choose a range: Use the Range selector to show only control characters, printable ASCII, or the extended set. 3. Read across the row: Each row lists decimal, hex, octal and binary alongside the rendered character. FAQ: Q: What is the difference between ASCII and extended ASCII? A: Standard ASCII defines code points 0-127 using 7 bits, covering control characters, digits, letters and common punctuation. Extended ASCII uses the 128-255 range and varies by code page (Latin-1, Windows-1252, etc.), so those glyphs are not universal. Q: Why do values 0-31 show abbreviations instead of characters? A: Code points 0-31 and 127 are non-printing control characters such as LF (line feed), CR (carriage return) and ESC (escape). They have no visible glyph, so the table shows their standard abbreviation instead. Q: How do I convert a character to its ASCII code? A: Type the character into the search box and read the Dec column for its decimal code. The Hex, Oct and Binary columns give the same value in base 16, 8 and 2. Q: Is the space character part of ASCII? A: Yes. Space is decimal 32 (hex 0x20), the first printable character. It is shown as SP in the table because a literal space is hard to see. Q: Does this tool send my input anywhere? A: No. The entire table is generated in your browser with JavaScript and filtered locally. Nothing you type is uploaded. #### Stellar Classification (Spectral Types) Reference URL: https://geratools.com/astronomy-stellar-classification Reference table for the Harvard stellar spectral classification with effective-temperature ranges, star colour and example stars, plus a temperature-to-spectral-class lookup. How to use: 1. Enter a temperature: Type a star's effective temperature in kelvin to find its Harvard spectral class. 2. Read the sequence: Review the O through M classes from hottest blue to coolest red with their temperature bands and example stars. 3. Compare your star: Use the colour and mass columns to place a star in context against the Sun and other named examples. FAQ: Q: What is the OBAFGKM sequence? A: It is the Harvard spectral classification, ordering stars by surface temperature from hottest to coolest: O, B, A, F, G, K and M. The mnemonic 'Oh Be A Fine Girl/Guy, Kiss Me' helps remember the order. The Sun is a G-type star. Q: How is spectral class linked to colour? A: Hotter stars peak at shorter wavelengths and look blue or blue-white (O and B), while cooler stars peak in the red and look orange or red (K and M). The Sun, a G-type star at about 5,800 kelvin, appears yellow-white. Q: What spectral type is the Sun? A: The Sun is class G2V. The G2 part places it in the G class near the hotter end, and the V is a luminosity class marking it as a main-sequence dwarf star. Its effective temperature is about 5,778 kelvin. Q: Why are M stars so common? A: Low-mass red dwarfs of class M are by far the most numerous main-sequence stars, making up roughly three quarters of all stars. They are cool, faint and very long-lived, so most stars in the galaxy are M-type even though few are visible to the naked eye. Q: Are there classes beyond M? A: Yes. Modern surveys add classes L, T and Y for very cool objects and brown dwarfs below the M range, plus rare classes like W for Wolf-Rayet stars. The classic OBAFGKM sequence still covers normal hydrogen-burning stars. #### AWG Wire Gauge Reference Table URL: https://geratools.com/awg-wire-gauge-table Full American Wire Gauge table from 0000 (4/0) through 40, with conductor diameter in millimetres and inches, cross-sectional area in square millimetres, and reference ampacity for chassis and power wiring. Runs in your browser. How to use: 1. Find your gauge: Browse the table or type a gauge such as 12, 0, or 4/0 to filter to the row you need. 2. Read diameter and area: Each row gives the bare-conductor diameter in millimetres and inches plus the cross-sectional area in square millimetres. 3. Check the ampacity: Use the chassis and power ampacity figures as a starting reference, then confirm against your local electrical code. FAQ: Q: How is AWG diameter calculated? A: AWG uses an exact geometric formula: diameter in millimetres equals 0.127 times 92 raised to the power (36 minus the gauge number) divided by 39. Each step of six gauges roughly halves the diameter, and ten gauges divides the area by about ten. Q: What do 4/0 and 0000 mean? A: Gauges thicker than 1 are written with multiple zeros: 1/0 (one ought), 2/0, 3/0, and 4/0 (four ought, also written 0000). In the formula they correspond to gauge numbers 0, minus 1, minus 2, and minus 3, getting progressively larger in diameter. Q: Why are two ampacity figures shown? A: Chassis wiring assumes a single insulated conductor in free air where heat dissipates easily, allowing higher current. Power transmission assumes conductors bundled or in conduit, where heat builds up, so the safe current is much lower. Real installations use the more conservative figure. Q: Does a higher AWG number mean thicker or thinner wire? A: Thinner. AWG is inverse: the larger the gauge number, the smaller the wire. A 40 AWG wire is hair-thin, while 0000 (4/0) is roughly half an inch across. This is the opposite of how most people first expect it to work. Q: Can I rely on this for wiring a circuit? A: Use it as a reference for diameter and area, but always size conductors for a real circuit using your national electrical code (such as the NEC) accounting for insulation rating, ambient temperature, conductor material, and installation method. The ampacity values here are general engineering references, not code values. #### awk Reference URL: https://geratools.com/awk-reference Searchable awk reference covering built-in variables (NR, NF, FS, OFS, RS), string functions (split, gsub, substr, match), numeric and I/O functions, and the BEGIN/END/range patterns — each with a working snippet. How to use: 1. Search a name: Type a variable like "NR", a function like "gsub", or a keyword like "field separator" to filter the reference instantly. 2. Narrow by group: Use the group selector to focus on built-in variables, string functions, numeric functions, I/O, or patterns. 3. Adapt the snippet: Each entry includes a short awk snippet showing the construct in context; copy it and substitute your own field numbers or regex. FAQ: Q: What is the difference between NR and FNR? A: NR is the cumulative record number across every input file, so it keeps counting as awk moves from one file to the next. FNR resets to 1 at the start of each file, which is useful for detecting headers or per-file logic. Q: How do I change the field separator in awk? A: Set the FS variable, either on the command line with -F',' or inside a BEGIN block with FS=",". For output, set OFS to control the separator that print places between fields. Q: What is the difference between sub and gsub? A: sub replaces only the first match of the regex in the target string and returns 0 or 1. gsub replaces every non-overlapping match and returns the total number of substitutions made. Q: How do I run code only once before or after processing? A: Use the special BEGIN pattern for setup code that runs before any input is read, such as setting FS or printing a header. Use END for code that runs after the last record, ideal for printing totals. Q: Are awk string positions zero-based or one-based? A: awk uses one-based indexing for strings and fields. substr(s,1,3) returns the first three characters, index returns 1 for a match at the start, and $1 is the first field. #### AWS Region Codes Reference URL: https://geratools.com/aws-region-codes Searchable AWS region reference with region code, geographic location, continent, availability-zone count and opt-in requirement for every commercial AWS Region. How to use: 1. Search regions: Type a code like eu-west-1 or a city to filter the AWS region list. 2. Filter opt-in regions: Use the dropdown to show only regions that require explicit account opt-in. 3. Read the location: Check the location column to map a code to its geographic data centre. FAQ: Q: What does a region code like eu-west-1 mean? A: AWS region codes follow a continent-direction-number pattern. eu-west-1 means Europe, west area, the first region launched there — physically Ireland. The number reflects launch order within the area, not a ranking. Q: Which AWS regions require opt-in? A: Regions launched after March 2019 — such as Hong Kong, Bahrain, Cape Town, Milan and Jakarta — are disabled by default and must be explicitly enabled in account settings before you can deploy resources there. Q: Why is us-east-1 special? A: us-east-1 (N. Virginia) is the oldest and largest AWS region and the default endpoint for many global services like IAM, Route 53 and CloudFront control planes. Some global API calls only work against us-east-1. Q: How many availability zones does a region have? A: Most AWS regions have three availability zones, though some have two and the largest have up to six. AZs are isolated data centres within a region, letting you build high-availability deployments that survive a single AZ failure. Q: Are GovCloud and China regions in this list? A: This reference focuses on the standard commercial partition (aws). AWS GovCloud (US) and the China regions run in separate partitions (aws-us-gov and aws-cn) with isolated accounts, so they are noted separately rather than mixed in. #### Azure RBAC Built-in Roles Reference URL: https://geratools.com/azure-rbac-roles-reference Searchable Azure RBAC built-in role reference covering Owner, Contributor, Reader and service-specific roles for Storage, Key Vault, VMs and AKS with scope and assignment notes. How to use: 1. Search the role: Type a role or service name such as Reader, Storage Blob or Key Vault to filter the built-in roles. 2. Read the scope and rights: Check whether the role grants management-plane, data-plane or assignment rights, and at which scope it makes sense. 3. Assign it: Use the role name with az role assignment create, scoping it to a resource group or single resource. FAQ: Q: What is the difference between Owner, Contributor and Reader? A: Owner has full access including managing other users' access (role assignments). Contributor can create and manage all resource types but cannot grant access to others. Reader can only view resources. All three are management-plane roles and do not by themselves grant data-plane access like reading blob contents. Q: Why can a Contributor not read blob data? A: Classic roles like Contributor and Owner act on the management plane — they manage the storage account itself. Reading or writing the actual blobs requires a data-plane role such as Storage Blob Data Reader or Storage Blob Data Contributor, which Azure separates so you can manage an account without seeing its contents. Q: What scopes can a role be assigned at? A: Azure RBAC assignments apply at four scopes that inherit downward: management group, subscription, resource group and individual resource. Assigning a role at a resource group grants it on every resource inside, so prefer the narrowest scope a principal actually needs. Q: Which role lets someone manage access without managing resources? A: User Access Administrator can manage role assignments (grant and revoke access) but not the resources themselves. It is the least-privilege way to delegate access management without giving full Owner rights over the resources. Q: How do I grant least-privilege Key Vault access? A: Use the data-plane roles: Key Vault Secrets User to read secrets, Key Vault Secrets Officer to manage them, Key Vault Crypto User for key operations. The management role Key Vault Administrator covers all data operations but not the account's Azure resource settings. #### Azure Region Codes Reference URL: https://geratools.com/azure-region-codes Searchable Azure region reference with internal region name, geography, display name, availability-zone support and the paired region used for platform-managed replication. How to use: 1. Search regions: Type an internal name like eastus or a city to filter the Azure region list. 2. Filter by zones: Use the dropdown to show only regions with availability-zone support. 3. Find the paired region: Read the paired-region column to see where platform replication targets. FAQ: Q: What is the difference between the internal name and display name? A: The internal name (like eastus or westeurope) is the lowercase code used in CLI, ARM templates and APIs. The display name (East US, West Europe) is the human-readable label shown in the Azure portal. They map one to one. Q: What is an Azure paired region? A: Most Azure regions are paired with another region in the same geography for platform-managed replication and sequential update rollout. For example East US pairs with West US, so geo-redundant storage replicates between them automatically. Q: Do all Azure regions support availability zones? A: No. Availability zones are physically separate data centres within a region, and only a subset of regions support them. Zone support is required for zone-redundant services and the highest single-region SLAs. Q: Why do some regions have no pair? A: Newer regions and some single-region geographies (such as certain Asian or government regions) are not paired. For those you must design cross-region redundancy yourself rather than relying on the platform pairing. Q: How are Azure regions grouped into geographies? A: A geography is a data-residency and compliance boundary that contains one or more regions, like United States or Europe. Geographies ensure data-residency and compliance requirements are honoured within market or sovereign boundaries. #### Beer Style Reference URL: https://geratools.com/beer-style-reference Reference table of major beer styles with typical ABV, bitterness (IBU) and colour (SRM) ranges from BJCP guidelines, plus a matcher that checks which styles a beer's numbers fall into. How to use: 1. Pick a family: Choose a beer family such as lager, ale, wheat, Belgian or sour to focus the list. 2. Filter or enter numbers: Type a style name, or enter a beer's ABV, IBU and SRM to see which styles those numbers fit. 3. Read the ranges: Compare the typical ABV, bitterness and colour ranges to understand or judge a style. FAQ: Q: What do ABV, IBU and SRM mean? A: ABV is alcohol by volume as a percentage. IBU (International Bitterness Units) measures hop-derived bitterness, where higher is more bitter. SRM (Standard Reference Method) measures colour, where roughly 2 is pale straw and 40 is opaque black. Q: Does a high IBU always mean a beer tastes very bitter? A: No. IBU measures iso-alpha-acid content, not perceived bitterness. A malty, high-alcohol beer can carry 70 IBU and taste balanced, while a hazy IPA with the same IBU can taste soft because residual sweetness and aroma mask the bitterness. Q: What is the difference between a lager and an ale? A: The split is about yeast and fermentation. Ales use top-fermenting yeast at warmer temperatures and often taste fruitier, while lagers use bottom-fermenting yeast cold-conditioned for a clean, crisp character. Both can span pale to black and light to strong. Q: Are these ranges strict rules? A: No. The figures follow BJCP style guidelines, which are descriptive targets for competition, not legal limits. Plenty of commercial beers sit slightly outside their declared style, so treat the ranges as typical rather than absolute. Q: How does the style matcher work? A: Enter any combination of ABV, IBU and SRM and the tool checks each value against every style's range. A style is flagged as a match only when all the numbers you entered fall inside its ranges, so leaving a field blank widens the matches. #### BMI Classification Reference URL: https://geratools.com/body-mass-index-reference Calculate BMI in metric or imperial and see the matching WHO category, from severe underweight through obese class III. Shows the full classification table with exact kg/m² cut-offs. Runs in your browser. How to use: 1. Choose units: Pick metric (kg and cm) or imperial (lb and ft/in) depending on how you measure. 2. Enter weight and height: Type your weight and height into the fields. The BMI updates instantly as you type. 3. Read your category: The tool shows your BMI value and highlights the matching WHO category in the full classification table. FAQ: Q: How is BMI calculated? A: BMI is your weight in kilograms divided by the square of your height in metres (kg/m²). In imperial units the formula is 703 multiplied by weight in pounds divided by height in inches squared. The result is a single number that places you in a category. Q: What is a healthy BMI range? A: The WHO defines a normal weight as a BMI of 18.5 to 24.9 kg/m². Below 18.5 is underweight and 25 or above is overweight, with obesity starting at 30. These cut-offs are screening thresholds for the general adult population. Q: Why might BMI be misleading? A: BMI cannot tell muscle from fat, so very muscular people can score as overweight despite low body fat. It is also not validated for children, pregnant people, or the very elderly, and the WHO suggests lower thresholds for many Asian populations. Q: What are the obesity classes? A: Obesity is split into class I (BMI 30 to 34.9), class II (35 to 39.9), and class III, sometimes called severe or morbid obesity, at 40 and above. Higher classes correlate with greater risk of cardiovascular and metabolic disease. Q: Does this work for children? A: No. Adult BMI cut-offs do not apply to children and teenagers, whose BMI must be interpreted against age and sex percentile charts. Use a paediatric BMI-for-age tool and consult a healthcare professional for anyone under 18. Q: How much weight change moves me between BMI categories? A: It depends on height, because BMI divides by height squared. At 170 cm, one full BMI point equals about 2.9 kg; at 190 cm it is about 3.6 kg. The normal band spans roughly 15–23 kg of body weight depending on height, so BMI moves slowly compared with daily scale fluctuations. #### Bolt Grade & Strength Reference URL: https://geratools.com/bolt-grade-strength-reference Reference table of bolt strength for metric property classes (4.6 to 12.9) and SAE grades (2, 5, 8) showing proof load, yield, and tensile strength, plus a proof-load estimator from thread stress area. How to use: 1. Find your bolt marking: Read the number stamped on the bolt head — a metric class like 8.8 or an SAE grade radial line count — and locate that row in the table. 2. Read the strength values: Each row lists nominal tensile strength, yield (or proof) strength, and proof load stress so you can compare grades at a glance. 3. Estimate proof load: Enter the thread tensile stress area to multiply it by the selected grade's proof stress and read the approximate proof load in kilonewtons. FAQ: Q: What do the two numbers in a metric class like 8.8 mean? A: The first number times 100 is the nominal tensile strength in MPa (8 means 800 MPa). The second number is the ratio of yield to tensile strength times 10 (8 means yield is 80 percent of tensile, so 640 MPa). Class 8.8 therefore has 800 MPa tensile and 640 MPa yield. Q: How do SAE grades compare to metric classes? A: SAE Grade 5 is roughly equivalent to metric class 8.8, and SAE Grade 8 is close to class 10.9. Grade 2 is unhardened low-carbon steel similar to class 4.6. The match is approximate because the standards define slightly different proof and yield points. Q: What is proof load? A: Proof load is the maximum tension a bolt can carry without taking a permanent set. It sits just below yield, typically 85 to 90 percent of yield strength, and is the figure used to set safe preload targets. Q: How do I turn a stress into a force? A: Multiply the stress in MPa by the thread tensile stress area in square millimetres to get force in newtons. An M10 coarse thread has a stress area of about 58 mm², so at 600 MPa proof stress it carries roughly 34.8 kN. Q: Why is yield lower than tensile strength? A: Tensile strength is the stress at fracture, while yield is where permanent deformation begins. A bolt loaded past yield but below tensile will stretch and lose preload even though it has not broken, which is why designs stay below proof load. #### BOM Byte-Order Mark Reference URL: https://geratools.com/bom-signatures Reference for text encoding byte-order marks with hex byte sequences and encoding identification rules. Paste the leading bytes of a file and detect which BOM, if any, it starts with. How to use: 1. Paste leading bytes: Enter the first few bytes of a file as hex, for example EF BB BF, with or without spaces. 2. Detect the BOM: The tool checks the bytes against every known byte-order mark and reports which encoding they signal. 3. Use the table: Browse the full BOM reference to compare hex sequences for UTF-8, UTF-16 and UTF-32 in both byte orders. FAQ: Q: What is a byte-order mark? A: A byte-order mark is the Unicode character U+FEFF placed at the very start of a text stream. Its encoded bytes reveal both the encoding and, for multi-byte encodings, whether the data is big-endian or little-endian. Q: Should I add a BOM to UTF-8 files? A: Usually no. UTF-8 has no byte-order to mark, and a leading EF BB BF can break shell scripts, JSON parsers, PHP output and CSV imports. Most tools expect UTF-8 without a BOM, so omit it unless a specific Windows program requires one. Q: How do UTF-16 LE and BE differ? A: UTF-16 little-endian starts with the bytes FF FE and stores the low byte of each unit first; big-endian starts with FE FF and stores the high byte first. The BOM lets a reader detect the order so the rest of the file is decoded correctly. Q: Why might a file show a wrong character at the start? A: A stray BOM that the application did not strip shows up as the visible sequence  (for a UTF-8 BOM mis-read as Latin-1) or a blank character. Detecting and removing the BOM, or telling the parser to expect one, fixes it. Q: Can UTF-8 and UTF-16 BOMs be confused? A: Not if you check enough bytes. A UTF-8 BOM is three bytes EF BB BF, while UTF-16 BOMs are two bytes (FF FE or FE FF) and the UTF-32 LE BOM is FF FE 00 00. Always test the longer sequences first so UTF-32 LE is not mistaken for UTF-16 LE. #### Braille Reference Chart URL: https://geratools.com/braille-reference-chart Visual reference of Grade 1 (uncontracted) English Braille. See the six-dot cell pattern for every letter, digit, and common punctuation mark, with dot numbers and a searchable grid. How to use: 1. Browse the cells: Scroll the grid to see the six-dot Braille cell for each character. 2. Search a character: Type a letter, digit, or dot pattern to filter the chart. 3. Read the dots: Filled dots are raised; the dot-number caption lists which positions are used. FAQ: Q: What is a Braille cell? A: A Braille cell is a grid of six dot positions arranged in two columns of three. Dots 1, 2, 3 run down the left column and 4, 5, 6 down the right. Any combination of raised dots forms a character. Q: What is Grade 1 Braille? A: Grade 1, or uncontracted Braille, spells out every word letter by letter with one cell per character. Grade 2 adds contractions where single cells stand for common words or letter groups, which this chart does not cover. Q: How are numbers written in Braille? A: Digits reuse the patterns for letters A through J, preceded by the number sign (dots 3, 4, 5, 6). So 1 is the same cell as A and 0 is the same cell as J once the number sign has appeared. Q: How is a capital letter shown? A: A capital sign (dot 6) is placed immediately before a letter to capitalise it. For an all-capital word, the capital sign is doubled. The letters themselves keep their normal patterns. Q: Is Braille the same in every language? A: The basic letter cells are widely shared, but each language defines its own accented letters, punctuation, and contractions. This chart shows standard English Braille; other languages add or remap cells. #### Canadian Province & Territory Reference URL: https://geratools.com/canadian-province-reference Searchable reference of Canada's 10 provinces and 3 territories with the ISO 3166-2 and Canada Post two-letter codes, capital cities, and a short note on each. Look up by code, name, or capital. How to use: 1. Type a search term: Enter a two-letter code, a province name, or a capital city to filter the table. 2. Read the entry: Each row shows the code, the province or territory name, its type, the capital, and a note. 3. Browse all 13: Leave the box empty to list all 10 provinces and 3 territories. FAQ: Q: How many provinces and territories does Canada have? A: Canada has 10 provinces and 3 territories, 13 in total. The territories — Northwest Territories, Yukon, and Nunavut — are in the north and derive their powers from the federal government rather than the constitution. Q: What is the code for Ontario? A: Ontario's two-letter code is ON. In full ISO 3166-2 form it is written CA-ON. The same two-letter portion is used by Canada Post for addressing mail. Q: What is the difference between a province and a territory? A: Provinces have constitutional authority of their own, while territories are administered under powers delegated by the federal Parliament. The three territories are far larger in area but much smaller in population. Q: Which is the newest territory? A: Nunavut, created in 1999 from the eastern part of the Northwest Territories. It is also the largest by area and has Iqaluit as its capital. Q: Is Ottawa a provincial capital? A: No. Ottawa is the federal capital of Canada and sits in Ontario, but Ontario's own provincial capital is Toronto. The two should not be confused. #### Carton & Board Weight Reference URL: https://geratools.com/carton-board-gsm-reference Reference table mapping g/m² (GSM) ranges to paper and board grades from tissue to solid board, with typical uses and a live GSM lookup to classify any paper weight. How to use: 1. Browse the GSM bands: Scan the weight bands from tissue and copy paper up to corrugated and solid board with their typical uses. 2. Look up a specific GSM: Enter a paper weight in g/m² and the tool classifies it into the matching grade with examples. 3. Compare to US basis weight: Use the approximate pounds-per-ream equivalents to translate GSM specs for US print suppliers. FAQ: Q: What does GSM mean? A: GSM stands for grams per square metre (g/m²), the mass of one square metre of a sheet. It is the international standard for specifying paper and board weight and, broadly, thickness — higher GSM means a heavier, stiffer sheet regardless of its size. Q: How does GSM relate to US basis weight? A: The US quotes paper in pounds per 500-sheet ream of a grade-specific basis size, so the same GSM maps to different pound figures for text, cover and index stock. As a rough guide, 90 gsm text ≈ 60 lb text, and 270 gsm cover ≈ 100 lb cover. Q: What GSM is a business card? A: Business cards are usually 300-400 gsm card stock for a stiff, premium feel. Standard office printer paper is 80 gsm, quality letterhead is around 100-120 gsm, and brochure covers sit near 250-300 gsm. Q: Is GSM the same as thickness? A: Not exactly. GSM measures weight per area, while thickness (caliper, in microns) measures depth. For a given paper type they correlate closely, but bulky or coated stocks of the same GSM can differ in thickness, so packaging specs often quote both. Q: Does this tool send my input anywhere? A: No. The GSM lookup and all grade data run locally in your browser. Nothing is transmitted. #### Clothing Care Symbol Reference URL: https://geratools.com/clothing-care-symbol-reference Reference for ISO 3758 / GINETEX textile care symbols covering washing, bleaching, drying, ironing and professional care, with a live filter to look up any laundry label icon and its meaning. How to use: 1. Find the symbol group: Identify whether the icon is a basin, triangle, square, iron or circle to know which care instruction it covers. 2. Filter to your symbol: Type a keyword such as wash, tumble or bleach to jump straight to the matching label icons. 3. Read the meaning: Apply the dot, bar and cross conventions to translate the icon into a concrete washing or drying instruction. FAQ: Q: What do the dots inside care symbols mean? A: Dots indicate temperature or heat level. Inside the ironing symbol one dot is low (~110 °C), two is medium (~150 °C) and three is high (~200 °C). Inside the tumble-dry circle, one dot is low heat and two dots is normal heat. Q: What does a cross through a symbol mean? A: A cross (X) over any care symbol means do not perform that action. A crossed-out basin means do not wash, a crossed triangle means do not bleach, and a crossed iron means do not iron or steam. Q: What do the bars under the wash basin indicate? A: Bars beneath the washing basin reduce the mechanical action. One bar means a mild or synthetics cycle, and two bars mean a very mild cycle such as the wool or delicate programme, both with gentler agitation and spin. Q: What is the difference between the P and F letters in the dry-clean circle? A: The letter inside the professional-care circle tells the cleaner which solvent to use. P means perchloroethylene or hydrocarbon solvents, F means hydrocarbon (petroleum) solvent only, and A means any solvent is acceptable. Q: Are these symbols the same worldwide? A: The ISO 3758 / GINETEX symbols shown here are used across the EU, UK and much of the world. North America uses a closely related ASTM set with the same shapes, though the US system sometimes adds extra dots or words. #### Cloud Classification Reference URL: https://geratools.com/cloud-classification-reference Reference table of the ten WMO cloud genera from cirrus to cumulonimbus, grouped by altitude étage with appearance, weather association and an étage filter. How to use: 1. Pick an altitude étage: Choose high, middle, low or vertical to narrow the list to clouds at that level of the atmosphere. 2. Filter by keyword: Type a word such as halo or anvil to find clouds by appearance or associated weather. 3. Match what you see: Compare the appearance notes with the sky overhead to identify the genus and anticipate the weather. FAQ: Q: What are the ten cloud genera? A: The World Meteorological Organization recognises ten base cloud genera: cirrus, cirrocumulus, cirrostratus, altocumulus, altostratus, nimbostratus, stratocumulus, stratus, cumulus and cumulonimbus. Every cloud belongs to one of these basic types. Q: What do the altitude étages mean? A: Clouds are grouped by the height of their base into étages: high (about 5 to 13 km), middle (2 to 7 km) and low (below 2 km). Cumulus and cumulonimbus span multiple levels and are classed as clouds of vertical development. Q: Which clouds signal rain? A: Nimbostratus brings steady prolonged rain or snow, and cumulonimbus produces heavy showers, hail and thunderstorms. A spreading veil of cirrostratus often warns that a warm front and rain are approaching within a day. Q: What does the prefix or suffix mean? A: Cirro- means high, alto- means middle, strato- means a flat layer and cumulo- means a heaped shape. The suffix -nimbus or prefix nimbo- marks a rain-bearing cloud, so nimbostratus is a rain-producing layer cloud. Q: Do genera have subtypes? A: Yes. Each genus divides further into species describing shape and structure, such as cumulus humilis, and into varieties describing arrangement and transparency. This reference covers the ten base genera. #### Coffee Roast Level Reference URL: https://geratools.com/coffee-roast-reference Reference guide to coffee roast levels with commercial Agtron score ranges, drop temperatures, first and second crack milestones and flavour notes, plus a live Agtron-to-roast lookup. How to use: 1. Find the roast level: Scan the roast levels from light to very dark with their Agtron ranges and drop temperatures. 2. Look up an Agtron score: Enter a commercial Agtron number to see which roast level it falls into and its flavour profile. 3. Read the crack and flavour: Use the crack milestones and tasting notes to match a roast level to the cup you want. FAQ: Q: What is an Agtron score? A: Agtron is a near-infrared colour scale used to measure roast degree objectively. On the commercial scale, higher numbers mean a lighter roast and lower numbers mean a darker roast, so a 70 is light and a 30 is very dark. Q: What are first crack and second crack? A: They are audible cracking sounds as beans roast. First crack, around 196 °C, is moisture escaping and marks the start of drinkable light roasts. Second crack, around 224 °C, is the bean structure fracturing and signals dark, oily roasts. Q: Does a darker roast have more caffeine? A: Not meaningfully by mass. Roasting changes flavour far more than caffeine, and the differences between light and dark are small. By weight they are nearly identical, though scooped by volume light roasts are slightly denser and can measure a touch higher. Q: Why do dark roasts look oily? A: As beans roast into second crack, oils migrate from the interior to the surface, giving dark roasts their characteristic sheen. Lighter roasts stay dry because they are dropped before those oils reach the surface. Q: Is this lookup done in my browser? A: Yes. The roast data and the Agtron-to-roast matching run entirely in your browser as a static reference. Nothing is fetched, uploaded or stored, so it works offline. #### Continent & Region Reference URL: https://geratools.com/continent-region-reference Reference table mapping countries to their continent and United Nations region and subregion classification (M49). Search or filter by continent, region, or country to see the standard geographic grouping. How to use: 1. Filter by continent: Pick a continent to show only the countries it contains, or leave it on all. 2. Search a country or region: Type a country, a UN region, or a subregion name to filter the list. 3. Read the grouping: Each row shows the country, its continent, UN region, and UN subregion. FAQ: Q: What is the difference between a continent and a UN region? A: A continent is a broad landmass grouping (Africa, Asia, Europe, etc.). The UN's M49 geoscheme divides the world into regions and finer subregions for statistical use — for example, Asia splits into Eastern Asia, Southern Asia, South-Eastern Asia, Western Asia, and Central Asia. The UN scheme is more granular than continents. Q: Which continent model does this use? A: This reference uses the common seven-continent model (Africa, Antarctica, Asia, Europe, North America, Oceania, South America) for the continent column, and the United Nations M49 standard for the region and subregion columns. The two systems do not always align — Russia, for example, spans Europe and Asia. Q: Why is Russia or Turkey ambiguous? A: Transcontinental countries straddle two continents. The UN places Russia in Eastern Europe and Turkey in Western Asia for statistical consistency, even though both have territory in two continents. This tool follows the UN classification for those edge cases. Q: Is Antarctica included? A: Antarctica is a continent but has no permanent population or sovereign states, only research stations governed by the Antarctic Treaty. It is noted as a continent but contributes no countries to the region list here. Q: Can I rely on this for official reporting? A: It is a convenient reference, but for official statistical work always cite the current UN Statistics Division M49 standard directly, as classifications and country memberships are periodically revised. #### Control Characters Reference URL: https://geratools.com/control-characters-reference Interactive reference for ASCII control characters 0-31 and DEL (127), including caret notation, C escape equivalents, abbreviations, full names and what each one does in modern systems. How to use: 1. Search a character: Type an abbreviation, name, decimal, hex or caret form like LF, 13 or ^C to filter the list. 2. Read the row: Each row gives the decimal, hex, caret notation, C escape, name and a usage note. 3. Map a Ctrl keystroke: Use the caret column to see which Ctrl+key combination produces each control code. FAQ: Q: What are ASCII control characters? A: Control characters are the non-printing codes 0-31 plus DEL (127) in ASCII. Instead of displaying a glyph, they signal actions such as newline, tab, backspace or interrupt. They form the C0 control set. Q: What is caret notation? A: Caret notation writes a control character as ^ followed by a letter, mapping Ctrl+key to a code. For example ^C is ETX (3), produced by pressing Ctrl+C, and ^? is DEL (127). The letter equals the code plus 64. Q: What is the difference between LF and CR? A: Line Feed (LF, 10, \n) moves down one line, while Carriage Return (CR, 13, \r) returns the cursor to the start of the line. Unix uses LF alone for newlines, Windows uses CR+LF, and classic Mac used CR alone. Q: Why does Ctrl+C interrupt a program? A: Ctrl+C sends the ETX control character (3), which terminals translate into a SIGINT signal. SIGINT asks the foreground program to stop, which is why it cancels running commands. Q: Are control characters still used today? A: Yes. NUL, LF, CR, HT (tab) and ESC are used constantly in text, terminals and protocols. ESC in particular begins every ANSI escape sequence. Others like the file/group/record/unit separators survive in data formats and legacy systems. #### ISO 3166-1 Country Codes URL: https://geratools.com/country-code-reference Searchable ISO 3166-1 country code reference: two-letter alpha-2, three-letter alpha-3 and three-digit numeric codes for each country, with UN region grouping and worked examples like GB, GBR and 826. How to use: 1. Search a country: Type a country name or any code such as "GB", "DEU" or "840" to filter the table instantly. 2. Filter by region: Pick a UN region like Europe or Africa to narrow the list to that part of the world. 3. Copy the code you need: Each row shows the alpha-2, alpha-3 and numeric codes together so you can grab the one your system expects. FAQ: Q: What is the difference between alpha-2 and alpha-3 country codes? A: Alpha-2 codes are two letters (GB, US) and are the most common, used in domains and locales. Alpha-3 codes are three letters (GBR, USA) and are more human-readable and collision-resistant, used in passports and some standards. Q: When should I use the numeric ISO 3166-1 code? A: The three-digit numeric code (826 for the UK) is language-independent and script-independent, which makes it ideal for systems that must avoid Latin letters, such as some financial messaging and statistical datasets. Q: Is the alpha-2 code the same as a country's top-level domain? A: Usually but not always. Most ccTLDs match the ISO 3166-1 alpha-2 code (.de for Germany), but there are exceptions like .uk (ISO code GB) and .eu, which is not a country code at all. Q: Do ISO 3166-1 codes ever change? A: Yes. Codes are reassigned when countries form, dissolve or rename. Retired codes (like CS for Serbia and Montenegro) are reserved and not immediately reused, so historical data should be interpreted with the date in mind. Q: How are region groupings determined? A: The region shown here follows the UN M.49 standard continental grouping (Africa, Americas, Asia, Europe, Oceania). M.49 also defines finer sub-regions, but the continental level is what most applications use for high-level segmentation. Q: Which codes are safe to use for test data or internal placeholders? A: Use the user-assigned ranges ISO promises never to allocate: alpha-2 codes AA, QM–QZ, XA–XZ, and ZZ; alpha-3 equivalents like XAA–XZZ; and numeric 900–999. Kosovo's conventional XK sits in this space, and ZZ is a common 'unknown country' sentinel. Q: Why does Armenia's numeric code sometimes appear as 51 instead of 051? A: Because a system stored the numeric code as an integer, which strips the leading zero. ISO 3166-1 numeric codes are three-character zero-padded strings (051, 004, 008); storing them as numbers breaks lookups against properly padded data. #### Cybersecurity Law by Country Reference URL: https://geratools.com/country-cybersecurity-law-reference Reference of major national data-protection and cybersecurity laws by country with the year in force and a scope note, covering GDPR, CCPA, LGPD, PIPL, DPDP and more, plus a live filter. How to use: 1. Browse the laws: Scroll the table to see major data-protection and cybersecurity laws grouped by country and region. 2. Filter for a jurisdiction: Type a country, region or law name to narrow the list to the markets you operate in. 3. Read the scope note: Use each scope note and year to understand what a law covers before consulting the regulator or counsel. FAQ: Q: Does GDPR apply to companies outside the EU? A: Yes. GDPR is extraterritorial: it applies to any organisation that offers goods or services to, or monitors the behaviour of, people in the EU, regardless of where the organisation is based. Non-EU controllers may need an EU representative. Q: What is the difference between CCPA and GDPR? A: GDPR is a comprehensive consent-and-rights regime covering all personal data of EU residents. The CCPA (and its successor the CPRA) is narrower, focused on consumer rights such as opting out of the sale or sharing of personal information for California residents. Q: Which laws have data-localisation requirements? A: China's PIPL and Cybersecurity Law impose strict cross-border transfer controls and localisation for certain data. Russia, India and several others also have localisation rules. Always check transfer mechanisms before moving personal data across borders. Q: Is this a complete list of cybersecurity laws? A: No. It highlights major national frameworks for orientation. Most countries layer sector-specific rules for finance, health and telecoms on top, and the landscape changes frequently. Treat it as a starting point, not an authoritative compliance source. Q: Is this legal advice? A: No. This reference is for general awareness only and does not constitute legal advice. Confirm your actual obligations with the relevant data-protection authority or qualified legal counsel for each jurisdiction. #### Emergency Phone Number by Country Reference URL: https://geratools.com/country-emergency-number-reference Searchable reference of emergency service telephone numbers by country — the general line plus separate police, ambulance and fire numbers — covering the UK 999, US 911, EU 112 and dozens more nations. How to use: 1. Search a country: Type a country name or ISO code to filter to the emergency numbers for that nation instantly. 2. Read the general line: The highlighted number reaches all services where one exists; 112 works across the EU and most mobile networks worldwide. 3. Use the service-specific lines: Where police, ambulance and fire have separate numbers they are listed below the general line so you dial the right one. FAQ: Q: Does 112 work everywhere? A: 112 is the single emergency number across all EU member states and works from any mobile in much of the world, often even without a SIM or with the keypad locked. In countries with a different primary number, 112 still frequently routes to emergency services from a mobile. Q: What is the difference between the general number and the police number? A: The general number connects you to an operator who dispatches whichever service you need. Some countries instead run separate lines for police, ambulance and fire, so you dial the specific one. This table shows both where they differ. Q: Why do some countries show a dash for the general number? A: A dash means there is no single all-services number in routine use; you must dial the specific police, ambulance or fire number listed alongside. Examples include Japan, China and Brazil. Q: Should I rely on this list while travelling? A: Use it as a quick guide, but always confirm the current local number on arrival, for example from official tourism or government sources. Emergency numbering can change and local exceptions exist. Q: Is any data sent over the network? A: No. The table is bundled with the page and all searching runs in your browser. Nothing is uploaded, logged or stored. #### Head of State Title by Country URL: https://geratools.com/country-head-of-state-reference Searchable reference of the head of state and head of government titles for sovereign countries, with the official designation, government type, and whether the role is ceremonial or executive. How to use: 1. Search a country: Type a country name to filter the table to matching rows. 2. Read the titles: See both the head of state and head of government title for that country. 3. Check the system: Note whether the head of state is ceremonial or executive under that government type. FAQ: Q: What is the difference between head of state and head of government? A: The head of state is the chief public representative of a country, such as a president or monarch. The head of government runs the executive branch day to day, often a prime minister. In presidential republics one person holds both roles. Q: Why do some countries have both a president and a prime minister? A: In parliamentary and semi-presidential systems the president is often a head of state with limited or ceremonial powers, while the prime minister leads the government. France, Germany, and India all split the roles this way. Q: What title does a monarchy use? A: Monarchies use titles such as King, Queen, Emir, Sultan, or Grand Duke for the head of state. In constitutional monarchies like the United Kingdom or Japan the monarch is ceremonial and a prime minister governs. Q: Is this list complete and current? A: It covers major sovereign states and common government types as a reference. Specific office-holders change with elections and successions, so always verify the current incumbent against an official government source before publishing. Q: What does ceremonial versus executive mean here? A: Ceremonial means the head of state has largely symbolic duties and the elected government holds real power. Executive means the head of state also directs policy and the administration, as in a presidential republic. #### Country Independence Date Reference URL: https://geratools.com/country-independence-date Searchable reference of national independence dates for sovereign states with the year, the former ruling power and a short note, from the US in 1776 to recent statehoods. How to use: 1. Search a country: Type a country name to jump straight to its independence date and the power it separated from. 2. Filter by region: Pick a UN region to compare independence dates across one part of the world, such as Africa or Asia. 3. Sort by year: Switch the sort to chronological order to see the waves of decolonization and state formation over time. FAQ: Q: What does an "independence date" actually mark? A: It marks the date a territory became a sovereign state, usually the formal declaration or the day legal sovereignty was transferred. For some nations there are several candidate dates (declaration, recognition, constitution) and countries pick the one they celebrate as their national day. Q: Why do some independence dates differ from the official national day? A: A national day may commemorate a declaration, a constitution, a revolution or unification rather than the legal transfer of sovereignty. This reference uses the widely cited statehood or independence date, which sometimes precedes or follows the official holiday. Q: What about countries that were never colonized? A: States such as Japan, Thailand and Ethiopia were never formal colonies, so their entry shows the founding or unification event instead of independence from a ruling power. The 'from' field notes this where relevant. Q: How are dates handled for countries that split or unified? A: For states formed by splitting from a predecessor (South Sudan from Sudan, the Czech Republic from Czechoslovakia) the date is that of the split. For unifications the date reflects the merger. The note column flags these cases. Q: Are these dates universally agreed? A: Mostly, but a few are disputed because declaration, recognition and effective control happened on different dates, or because sovereignty is contested. Treat edge cases as approximate and cross-check against the country's own constitution or national archive. #### CPT Code Section Reference URL: https://geratools.com/cpt-code-section-reference Reference guide to the six Category I CPT code sections and their numeric ranges used in US medical billing, with a 5-digit code-to-section lookup. Covers Anesthesia, Surgery, Radiology, Pathology, Medicine and E&M. #### CPU Socket Reference URL: https://geratools.com/cpu-socket-reference Reference table of desktop CPU sockets — Intel LGA1700, LGA1851, LGA1200, AMD AM4, AM5 and more — with pin type, supported processor families and the years each socket was current. How to use: 1. Find your socket: Browse the table of Intel and AMD desktop sockets with the processor families each one supports. 2. Filter by socket or CPU: Type a socket name like 'AM5' or a chip like 'Ryzen 7000' to narrow the list. 3. Check compatibility: Match your CPU to its socket and confirm the motherboard uses the same socket and a supporting chipset and BIOS. FAQ: Q: Does matching the socket guarantee a CPU will work? A: No. A matching socket is necessary but not sufficient. The motherboard chipset must support the CPU generation, and the board may need a BIOS update for newer chips on the same socket. Always check the board maker's CPU support list before buying, especially when mixing generations that share a socket. Q: What is the difference between LGA and PGA sockets? A: LGA (Land Grid Array) puts the pins on the motherboard socket and flat contact pads on the CPU — used by modern Intel and by AMD's AM5. PGA (Pin Grid Array) puts the pins on the CPU itself, which slots into holes in the board — used by AMD's long-lived AM4. Bent pins are on whichever side carries them. Q: How long did AMD's AM4 socket last? A: Unusually long. AM4 launched in 2016 and supported Ryzen 1000 through 5000 (and some later 5000-series refreshes), spanning roughly seven years and five CPU generations. That longevity let many users upgrade CPUs without replacing the motherboard, though BIOS updates were often required for newer chips. Q: Can I put a newer Intel CPU in an older LGA socket? A: Only if they share the exact same socket and the chipset supports the CPU. Intel often changes sockets every one to two generations — for example LGA1200 (10th/11th gen) gave way to LGA1700 (12th–14th gen) and then LGA1851 (Core Ultra). Different socket means physically incompatible, regardless of BIOS. Q: Does this reference store what I type? A: No. The table and filter run entirely in your browser using JavaScript. Nothing you enter is uploaded, logged or stored. #### Top Cryptocurrency Ticker Reference URL: https://geratools.com/cryptocurrency-ticker-reference Searchable reference of major cryptocurrency tickers — BTC, ETH, SOL, USDT and dozens more — with full coin name, underlying chain or consensus, and launch year. Symbol-to-name lookup, no live prices. How to use: 1. Search by ticker or name: Type a ticker like SOL, a coin name like Solana, or a chain keyword like rollup or stablecoin to filter instantly. 2. Read the chain: Each row shows the primary network or consensus mechanism so you can tell a base-layer coin from an ERC-20 token. 3. Check the launch year: Use the launch year to gauge maturity and to distinguish original chains from later forks or layer-2 networks. FAQ: Q: Are cryptocurrency tickers officially registered? A: No. Unlike stock symbols there is no central registry, so tickers are conventional and an exchange can list variants. Most major coins have a widely agreed ticker, but wrapped or bridged versions may carry a prefix such as W or a chain suffix. Q: What is the difference between a coin and a token here? A: A coin runs on its own base-layer chain (BTC on Bitcoin, ETH on Ethereum). A token lives on another chain's smart-contract standard, like an ERC-20 token on Ethereum. The chain column shows which case applies for each entry. Q: Why do some entries say stablecoin? A: Stablecoins such as USDT, USDC and DAI aim to track a fiat currency, usually the US dollar. They are issued across several chains at once, so the chain column marks them as multi-chain rather than naming a single network. Q: Does this tool show live prices? A: No. Prices move every second and are out of scope. This is a static symbol-to-name and chain lookup so you can decode a ticker you have seen, not a market data feed. Q: Is any data sent over the network? A: No. The whole table ships with the page and all searching runs in your browser. Nothing is uploaded, logged or stored. #### ISO 4217 Currency Codes URL: https://geratools.com/currency-code-reference Searchable ISO 4217 currency reference: three-letter alphabetic code, three-digit numeric code, number of minor-unit (decimal) digits and country for each currency, including zero-decimal currencies like JPY and KRW. How to use: 1. Search a currency: Type a currency name, code or country such as "Euro", "JPY" or "Armenia" to filter the table. 2. Filter by decimal digits: Pick a minor-unit group to see only currencies with that many decimal places, such as 0 for JPY and KRW. 3. Read the minor-unit count: Each row shows how many fractional digits the currency uses, which is essential for storing money in integer minor units. FAQ: Q: What is a minor unit in ISO 4217? A: The minor unit is the number of decimal digits a currency normally uses. USD has 2 (cents), JPY has 0 (no fractional yen), and BHD has 3 (fils). It tells you how to format and store amounts. Q: Why do some currencies have 0 decimal places? A: Currencies like JPY, KRW, VND and UGX have no commonly used fractional subdivision, so ISO 4217 sets their minor unit to 0. When storing these in integer minor units, one major unit equals one minor unit. Q: How do I store money safely using these codes? A: Store amounts as integers in the smallest minor unit (cents, fils) and keep the currency code alongside, then divide by 10^minor only for display. This avoids floating-point rounding errors entirely. Q: What is the numeric currency code for? A: The three-digit numeric code mirrors the country's ISO 3166-1 numeric code where possible and is script-independent, which makes it useful in financial messaging formats and systems that avoid Latin letters. Q: Are codes like XAU and XDR real currencies? A: They are ISO 4217 codes but not national currencies. XAU is one troy ounce of gold, XDR is the IMF Special Drawing Right. Codes starting with X are reserved for supranational, metal or testing uses. #### Customs Procedure Code Reference URL: https://geratools.com/customs-procedure-code-reference Reference of customs procedure codes (CPCs) used in UK CHIEF and the current CDS and EU declaration model. Filter by system and keyword to find codes for free circulation, inward processing, customs warehousing, returned goods relief, and export. How to use: 1. Choose a system: Filter to the legacy CHIEF seven-digit codes or the current CDS requested and additional procedure codes. 2. Search the code: Type a code fragment or a keyword such as warehouse or returned goods to narrow the list. 3. Read the treatment: Each entry explains the customs treatment the code applies, whether import or export. FAQ: Q: What is a customs procedure code? A: A customs procedure code, or CPC, tells customs what treatment to give the goods on a declaration: whether they are being released to free circulation, entered to a special procedure such as inward processing, warehoused, or exported. It drives how duty, VAT, and reliefs are applied. Q: What does CPC 40 00 000 mean? A: 40 00 000 is the most common UK CHIEF import code. It declares goods to free circulation and home use with no previous procedure, meaning a standard import on which duty and import VAT are paid. The CDS equivalent is requested procedure 40 with previous procedure 00. Q: What is the difference between CHIEF and CDS codes? A: CHIEF used a single seven-digit CPC. CDS, the system that replaced CHIEF, breaks the same information into a four-digit code made of a requested procedure and a previous procedure, plus one or more three-character additional procedure codes such as F01 or 000. Q: Which code is used for inward processing? A: Inward processing, where goods are imported for processing with import duty suspended, is declared with CHIEF code 51 00 000 or CDS requested procedure 51 with previous procedure 00. It lets a business import, process, and re-export without paying duty on the imported components. Q: What additional procedure code means no other procedure applies? A: In CDS the additional procedure code 000 means no other procedure applies; it is the common default added when no special relief or condition is being claimed. Other additional codes such as C07 for low-value relief or F01 for returned goods relief replace it when a relief is claimed. Q: How do I read the two halves of a CDS procedure code like 6121? A: The first two digits are the requested procedure (what you want now) and the last two are the previous procedure (what the goods were under before). 6121 asks for re-import to free circulation (61) after a previous permanent export (21). A previous-procedure half that doesn't match the goods' actual history is a common rejection cause. #### Depreciation Method Reference URL: https://geratools.com/depreciation-method-reference Reference for the common depreciation methods — straight-line, declining balance, double-declining balance and sum-of-years-digits — with formulas, use cases and a live year-by-year schedule builder. How to use: 1. Pick a method: Choose straight-line, declining balance, double-declining or sum-of-years-digits to match how the asset loses value. 2. Enter the asset details: Type the asset cost, salvage value and useful life in years; the schedule recalculates instantly. 3. Read the schedule: Each row shows that year's depreciation and the remaining book value so you can compare front-loaded versus even methods. FAQ: Q: What is the difference between straight-line and declining balance? A: Straight-line spreads the depreciable amount evenly across every year of the asset's life. Declining balance applies a fixed rate to the shrinking book value, so it front-loads the expense and depreciates more in the early years. Q: What is salvage value and how does it affect the calculation? A: Salvage (or residual) value is what the asset is expected to be worth at the end of its life. Straight-line and sum-of-years-digits subtract it from cost before depreciating. Declining-balance methods ignore it in the rate but stop depreciating once book value reaches it. Q: Why does double-declining balance use a factor of 2? A: Double-declining balance applies twice the straight-line rate (2 ÷ life) to the book value each year. The 150% variant uses 1.5 ÷ life. Both accelerate expense recognition for assets that lose value fastest when new. Q: How does sum-of-years-digits work? A: Add the digits of the asset's life (for 5 years: 5+4+3+2+1 = 15). Each year's fraction is the remaining life over that sum, applied to cost minus salvage. It accelerates depreciation but more gently than double-declining balance. Q: Does this tool send my figures anywhere? A: No. The entire schedule is computed in your browser with JavaScript. Nothing is uploaded, logged or stored. #### Gang of Four Design Pattern Reference URL: https://geratools.com/design-pattern-reference Searchable reference of all 23 Gang of Four design patterns grouped into Creational, Structural and Behavioural, each with its intent and a typical use case, plus a keyword filter. How to use: 1. Search a pattern: Type a name or a phrase like decouple or undo to filter the 23 patterns by name, intent or use. 2. Filter by group: Switch to Creational, Structural or Behavioural to browse one family of patterns. 3. Read intent and use: Each card states the pattern's intent and a real-world use case so you can judge when it fits. FAQ: Q: What are the three categories of GoF patterns? A: Creational patterns deal with object creation (5 patterns like Factory Method and Singleton). Structural patterns compose objects into larger structures (7, like Adapter and Decorator). Behavioural patterns manage communication and responsibility (11, like Observer and Strategy). Q: What is the difference between Strategy and State? A: Both swap behaviour behind an interface. Strategy lets a client choose an interchangeable algorithm, like a sorting or pricing method. State changes behaviour as an object moves through its own lifecycle, and the transitions are usually internal rather than client-selected. Q: When should I avoid the Singleton pattern? A: Singletons introduce hidden global state that makes testing and concurrency harder, so use them sparingly. Prefer passing dependencies explicitly (dependency injection). Reserve a true singleton for genuinely single resources like a configuration registry or connection pool. Q: Are these patterns still relevant in modern languages? A: Yes, though some are built into the language. Iterator and Observer are often native, and first-class functions can replace Strategy or Command with a closure. The patterns remain a shared vocabulary for describing structure and intent across teams. Q: Does this reference send my searches anywhere? A: No. Filtering happens entirely in your browser. Nothing you type is uploaded, logged or stored. #### GoF Design Patterns Reference URL: https://geratools.com/design-patterns-reference Searchable Gang of Four design pattern reference: all 23 creational, structural and behavioral patterns with their intent and the situation each one solves, so you can pick the right pattern by problem. How to use: 1. Search by name or problem: Type a pattern name or a keyword from the problem you face, such as undo or tree. 2. Filter by family: Narrow to creational, structural or behavioral patterns to browse a related group. 3. Match intent to your problem: Read the intent and the when-to-use note to confirm the pattern fits before applying it. FAQ: Q: What are the three categories of GoF patterns? A: Creational patterns abstract how objects are made (Factory, Builder, Singleton, Prototype, Abstract Factory). Structural patterns compose objects into larger structures (Adapter, Decorator, Facade, Proxy, Composite, Bridge, Flyweight). Behavioral patterns assign responsibilities and manage communication between objects (Observer, Strategy, Command, State, and seven more), for 23 patterns in total. Q: What is the difference between Strategy and State? A: Both swap behavior behind an interface, but their intent differs. Strategy lets a client choose an interchangeable algorithm explicitly, such as a sorting or pricing strategy. State lets an object change its own behavior as its internal state transitions, so it appears to change class — the object, not the client, drives the switch. Q: When should I reach for a design pattern? A: Only when the problem the pattern solves is actually present. Patterns are shared vocabulary for recurring designs, not goals in themselves. Forcing a pattern onto simple code adds indirection without benefit; the SOLID and KISS principles warn against this. Recognize the problem first, then name the pattern. Q: Is Singleton an anti-pattern? A: It is the most criticized GoF pattern because it introduces global state, hides dependencies, and complicates testing. It is fine for genuinely single shared resources like a configuration object, but prefer dependency injection so the single instance is passed in rather than fetched from a global accessor. Q: What is the difference between Adapter, Facade and Proxy? A: All three wrap another object but for different reasons. An Adapter converts one interface into another the client expects. A Facade gives a simple unified entry point to a complex subsystem. A Proxy provides a stand-in with the same interface to control access, add lazy loading, caching, or remote calls. #### Display Resolution Reference URL: https://geratools.com/display-resolution-reference Reference table of standard display resolutions — QVGA, VGA, XGA, HD, Full HD, QHD, 4K UHD, 5K, 8K and 16K — with width, height, total pixels, aspect ratio, and a built-in aspect-ratio calculator. How to use: 1. Search a resolution: Type a name like 4K, QHD, or 1080p, or paste a dimension like 1920x1080 to find its standard name. 2. Read aspect and pixel count: Each row shows the reduced aspect ratio and total megapixels so you can compare display density at a glance. 3. Compute a custom ratio: Enter any width and height in the calculator to get the simplified aspect ratio and total pixel count. FAQ: Q: What aspect ratio is 1920x1080? A: 1920x1080 has a 16:9 aspect ratio. Dividing both by their greatest common divisor of 120 gives 16:9, the standard widescreen ratio used by Full HD, QHD, and 4K UHD. Q: How many more pixels does 4K have than 1080p? A: 4K UHD is 3840x2160, which is exactly four times the pixels of 1920x1080. It packs about 8.3 megapixels versus roughly 2.1 megapixels for 1080p. Q: What is the difference between 4K UHD and DCI 4K? A: 4K UHD is 3840x2160 (16:9) used by consumer TVs and monitors. DCI 4K is 4096x2160, a slightly wider cinema standard defined by the Digital Cinema Initiatives for theatrical projection. Q: Why are ultrawide resolutions like 3440x1440 not 16:9? A: Ultrawide displays use a 21:9 (or 64:27) aspect ratio. 3440x1440 reduces to roughly 43:18, marketed as 21:9, giving extra horizontal space for productivity and gaming. Q: What does QHD mean compared to FHD? A: QHD (Quad HD) is 2560x1440, which is four times the pixels of HD 720p, not Full HD. FHD (Full HD) is 1920x1080. QHD sits between Full HD and 4K in pixel density. #### Engine Oil Viscosity Grade Reference URL: https://geratools.com/engine-oil-viscosity-reference Reference table for SAE multigrade engine oil viscosity grades explaining the winter (W) number and operating-temperature number, with cold-start and hot-flow temperature suitability. How to use: 1. Read the grade format: Understand a grade like 5W-30: the W number is cold-weather flow, the second number is hot operating viscosity. 2. Look up a grade: Enter a grade such as 5W-30 to see its lowest safe cold-start temperature and high-temperature behaviour. 3. Match to your climate and manual: Pick a grade your owner's manual approves that also flows at your coldest expected temperature. FAQ: Q: What does 5W-30 mean? A: It is a multigrade oil. The 5W (W for winter) describes how easily it flows when cold — lower numbers stay fluid at colder temperatures for easier starts. The 30 describes its viscosity at the engine's hot operating temperature, around 100°C; higher numbers are thicker when hot. Q: Is a lower or higher W number better? A: A lower W number (0W, 5W) flows better in the cold, protecting the engine on start-up and improving fuel economy in winter. There is no downside in summer because multigrade oils behave the same once warm, so manufacturers increasingly specify 0W and 5W grades. Q: Can I use a thicker oil than specified? A: Generally no. Modern engines have tight tolerances and oil pumps designed for a specific grade. Using a thicker oil than the manual specifies can starve narrow oil galleries and worsen cold starts and economy. Always follow the manufacturer's specification. Q: What is the second number measured against? A: The high-temperature number is set by SAE J300 based on kinematic viscosity at 100°C and a high-temperature high-shear (HTHS) test at 150°C. A 40-grade oil keeps more film strength under load and heat than a 20-grade, which matters for high-output or towing engines. Q: Is this lookup processed online? A: No. All grade data and the lookup run locally in your browser. Nothing is transmitted. #### POSIX errno Reference URL: https://geratools.com/errno-reference Cross-platform errno reference with POSIX, Linux-specific and macOS/BSD values side by side, plus the meaning of each constant. Searchable by name or number, runs entirely in your browser. How to use: 1. Search a constant: Type a name like ENOENT, a number like 2, or a keyword such as permission to filter the table. 2. Compare platforms: The Linux and macOS/BSD columns show the numeric value on each platform, so you can see where the same name maps to different numbers. 3. Match by name, not number: Because numbers diverge above 34, always compare errno by its symbolic name across platforms — for example EAGAIN is 11 on Linux but 35 on macOS. FAQ: Q: What is errno? A: errno is a thread-local integer set by system calls and library functions to indicate why the last operation failed. After a call returns an error, you read errno (or use strerror) to learn the specific cause, such as ENOENT for a missing file. Q: Why do errno numbers differ between Linux and macOS? A: The low values 1 to 34 are shared across most Unix systems, but beyond that Linux and the BSD-derived macOS assign different numbers to the same symbolic name. EAGAIN is 11 on Linux and 35 on macOS, so code that compares raw numbers across platforms breaks — always compare by name. Q: What does ENOENT mean? A: ENOENT (2) is No such file or directory. A path you passed to open, stat, exec or a similar call does not exist, or a component of the path is missing. It is one of the most common errno values. Q: What is the difference between errno and an exit code? A: errno is an in-process value describing why a system call failed, set continuously as the program runs. An exit code is the single byte a process returns to its parent when it terminates. A program may convert an errno into an exit code, but they are distinct mechanisms. Q: Is anything I search uploaded? A: No. The errno table and search run entirely in your browser, so nothing you type is sent anywhere. #### Unix Exit Codes Reference URL: https://geratools.com/exit-codes-reference Reference for Unix process exit codes including POSIX conventions, bash special codes (126, 127, 128+N) and the sysexits.h values (64-78). Searchable and runs entirely in your browser. How to use: 1. Search a code: Type an exit code like 127, a source like sysexits, or a keyword such as SIGKILL to filter the list. 2. Decode signal deaths: Codes from 128 upward mean death by a signal: subtract 128 to get the signal number, so 137 is 128 + 9 (SIGKILL). 3. Read the source column: The source column shows whether a code is a POSIX convention, a bash special value, or from BSD sysexits.h, which tells you how universal it is. FAQ: Q: What does exit code 0 mean? A: Exit code 0 means success — the command completed without error. By Unix convention any non-zero value indicates failure, which is why shell tests like if command; then treat 0 as true. Q: What does exit code 127 mean? A: Exit code 127 means command not found. The shell could not locate the program in PATH, usually because of a typo, a missing binary, or PATH not including the directory. Exit code 126 is related: the file was found but is not executable. Q: What does exit code 137 mean? A: Exit code 137 is 128 + 9, meaning the process was killed by SIGKILL (signal 9). This is frequently the Linux out-of-memory killer terminating a process, or a forced kill -9. Check memory limits and system logs. Q: Are exit codes the same as errno? A: No. An exit code is the single byte a process returns when it finishes (0-255), reported to its parent. errno is an in-process integer set by system calls to describe the last error. A program may translate an errno into an exit code, but they are different mechanisms. Q: Is anything I search uploaded? A: No. The exit-code table and the search run entirely in your browser, so nothing you type leaves your device. #### FTP Reply Codes Reference URL: https://geratools.com/ftp-reply-codes Searchable FTP reply code reference from RFC 959. Look up any three-digit code, decode what its first and second digits mean, and read the plain-English description and category. How to use: 1. Search by code or text: Type a number like 550, a phrase like passive, or words from the message. The list filters as you type. 2. Filter by first digit: Choose 1xx through 5xx to focus on preliminary, success, intermediate, transient-failure or permanent-failure replies. 3. Read the description: Each row shows the category and a plain-English description, plus a copy button to paste into logs or docs. FAQ: Q: How are FTP reply codes structured? A: Every FTP reply is three digits. The first digit is the completion status: 1 preliminary, 2 success, 3 intermediate, 4 transient failure, 5 permanent failure. The second digit is the functional group such as syntax, information, connections, authentication or file system. The third digit gives a finer-grained meaning within that group. Q: What does FTP 227 mean? A: 227 is Entering Passive Mode. The server replies with a host and port encoded as six comma-separated numbers (h1,h2,h3,h4,p1,p2), and the client opens the data connection to that address. EPSV uses 229 instead, returning just a port, which works better through NAT and IPv6. Q: Why do I get FTP 530 Not logged in? A: 530 means authentication is required or failed. It appears when you send a command before logging in, when the username or password is wrong, or when the server requires TLS (AUTH TLS) before accepting credentials. It is a permanent failure for that attempt, so fix the credentials or enable TLS. Q: What is the difference between FTP 4xx and 5xx codes? A: A 4xx reply is a transient negative completion — the command failed but the condition is temporary, so retrying later may succeed (server busy, no storage, data connection failed). A 5xx reply is a permanent negative completion such as bad syntax, file not found, or insufficient permissions, where retrying the same request will not help. Q: Is this FTP reference private? A: Yes. The full reply-code table, search and filtering all run locally in your browser with no account and no network calls. Nothing you type leaves the page. #### Fuel Octane Rating Reference URL: https://geratools.com/fuel-octane-reference Reference table comparing RON, MON and AKI octane ratings for petrol grades by country, explaining how the three scales relate and which pump number each country displays. How to use: 1. Understand the three scales: Learn how RON, MON and AKI are measured and why the same fuel shows different numbers in different countries. 2. Convert a rating: Enter a known RON or AKI value and the tool estimates the equivalent on the other scales. 3. Match grade to your engine: Use the country table to find the pump grade that meets your vehicle's minimum octane requirement. FAQ: Q: What is the difference between RON, MON and AKI? A: RON (Research Octane Number) is measured under mild test conditions and is the figure shown on European and most Asian pumps. MON (Motor Octane Number) uses harsher conditions and is a few points lower. AKI (Anti-Knock Index), shown in the US and Canada, is the average of the two: (RON + MON) / 2. Q: Why is US 87 the same as European 91-92? A: Because the US displays AKI (the RON/MON average) while Europe displays RON. US regular at 87 AKI is roughly 91-92 RON, mid-grade 89 AKI ≈ 93-94 RON, and premium 91-93 AKI ≈ 95-98 RON. The fuel is comparable; only the displayed scale differs. Q: Does higher octane give more power? A: Only if your engine needs it. Octane measures resistance to knock (pre-ignition), not energy content. Engines tuned for high octane make more power and efficiency on it; in a low-compression engine, premium fuel gives no benefit. Always meet, but rarely exceed, the manufacturer's minimum. Q: What happens if I use lower octane than required? A: The engine may knock — uncontrolled detonation that can damage pistons and valves. Modern engines retard ignition timing to prevent knock, which reduces power and economy. Persistently under-fuelling a high-compression engine risks long-term damage, so meet the specified minimum. Q: Is this conversion done online? A: No. The octane scale conversion and country data run entirely in your browser. Nothing is sent anywhere. #### G20 Member Reference URL: https://geratools.com/g20-country-reference Reference table of the G20 members with nominal GDP, share of world economy, population and region, covering the 19 countries plus the EU and African Union blocs. How to use: 1. Browse the members: Scan the G20 members with their GDP, share of the world economy, population and region. 2. Sort the table: Sort by GDP, world share or population to compare the relative size of each economy. 3. Read the totals: See the combined G20 share of the world economy and total population at the foot of the table. FAQ: Q: Who are the members of the G20? A: The G20 comprises 19 individual countries — Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United Kingdom and the United States — plus the European Union and, since 2023, the African Union as bloc members. Q: What share of the world economy is the G20? A: G20 members together account for around 85% of global GDP, roughly two-thirds of the world's population and about three-quarters of international trade, which is why it is the premier forum for international economic cooperation. Q: When was the African Union added? A: The African Union was admitted as a permanent member at the 2023 New Delhi summit, becoming the second bloc member alongside the European Union, which is why the forum is sometimes called the G21. Q: Are the GDP figures exact? A: No. The figures are approximate nominal GDP in current US dollars rounded for reference. They shift year to year with growth and exchange rates, so treat them as orders of magnitude rather than precise accounts. Q: Is this data sent anywhere? A: No. The table and sorting run entirely in your browser. Nothing is uploaded, logged or stored. #### Gemstone Properties Reference URL: https://geratools.com/gemstone-reference Reference table of 50+ gemstones listing Mohs hardness, refractive index, specific gravity and crystal system, so you can compare and identify stones by their key gemmological properties. How to use: 1. Search for a stone: Type a gemstone name, crystal system or property value to filter the table. 2. Compare key properties: Read each stone's Mohs hardness, refractive index, specific gravity and crystal system across the row. 3. Use it to narrow identification: Match a measured RI or hardness against the table to shortlist candidate gemstones. FAQ: Q: What is the Mohs hardness scale? A: The Mohs scale ranks a mineral's scratch resistance from 1 (talc) to 10 (diamond). Each step means the higher mineral scratches the lower. Hardness alone does not identify a gem, but it helps narrow candidates and indicates durability for jewellery. Q: How does refractive index help identify gemstones? A: Refractive index (RI) measures how much a stone bends light and is one of the most reliable identifiers. Measured on a refractometer, an RI reading combined with hardness, specific gravity and optical character usually pins down the species. Q: What is specific gravity? A: Specific gravity (SG) is a stone's density relative to water. A 3.52 SG diamond feels heavier than a same-size 2.66 quartz. Gemmologists measure it by hydrostatic weighing or heavy-liquid testing to support identification. Q: Is a higher Mohs hardness always better for jewellery? A: Generally yes for durability, but toughness also matters. Diamond is hardest (10) yet can cleave on impact, while jade is softer (around 6.5) but extremely tough. For rings, a hardness of 7 or above resists everyday scratching well. Q: Does this reference work offline? A: Yes. The full gemstone property table is built into the page and filtering runs entirely in your browser. Nothing is uploaded or stored. #### Glove Size Reference Chart URL: https://geratools.com/glove-size-chart Convert a hand circumference measurement into a glove size across S/M/L, US numeric, and EU numeric systems. Measure around your palm and read the matching size, or browse the full reference table for work, sport, and dress gloves. Runs in your browser. How to use: 1. Measure your hand: Wrap a tape measure around the widest part of your dominant hand, just below the knuckles, excluding the thumb. Record the circumference in inches or centimetres. 2. Enter the value: Type the circumference into the lookup and choose your unit. The tool converts to the standard glove sizing bands. 3. Read the size: The closest band is highlighted, showing the letter size (S/M/L), the US numeric size, and the EU numeric equivalent. FAQ: Q: How do I measure my hand for gloves? A: Wrap a flexible tape around the fullest part of your palm, just below the knuckles and excluding the thumb. Keep your hand relaxed and flat. The resulting circumference, in inches or centimetres, is the primary measurement glove makers use for sizing. Q: What is the difference between US and EU glove sizes? A: US numeric glove sizes (6 to 11) roughly equal the hand circumference in inches. EU sizes use a slightly different numeric scale, typically one to two numbers higher. This chart maps both to the same physical measurement so you can convert between them. Q: Should I measure my left or right hand? A: Measure your dominant hand, which is usually slightly larger. Gloves are sold in pairs sized to the larger hand, so if your hands differ noticeably, size to the bigger one to avoid a tight fit. Q: Do work gloves and dress gloves fit the same? A: Not always. Work and safety gloves are often cut roomier for liners and dexterity, while dress and athletic gloves fit close. Use this chart as a baseline, then size up one band for insulated or layered work gloves. Q: What if I am between two sizes? A: Size up for comfort and circulation, especially for cold-weather or work gloves where a snug fit reduces warmth and dexterity. For grip-critical sport gloves, the tighter of the two sizes usually performs better. #### GSM / LTE Band Reference URL: https://geratools.com/gsm-band-reference Reference table of 3GPP LTE and 5G NR frequency bands with uplink/downlink ranges, duplex mode (FDD/TDD) and regional deployment, plus a live band lookup search. How to use: 1. Browse the band table: Scan the LTE and 5G NR bands with their uplink and downlink frequency ranges and duplex mode. 2. Search by band or frequency: Type a band number like 7 or n78, or a frequency like 1800 to filter the list to matching bands. 3. Check duplex and region: Use the FDD/TDD column and regional notes to confirm a band is deployed where your device operates. FAQ: Q: What is the difference between FDD and TDD? A: FDD (Frequency Division Duplex) uses separate uplink and downlink frequency blocks at the same time. TDD (Time Division Duplex) uses one shared block, alternating uplink and downlink in time slots. TDD suits asymmetric data, FDD suits low-latency voice. Q: Why do 5G bands start with the letter n? A: 3GPP prefixes 5G New Radio band numbers with n (for example n78, n258) to distinguish them from LTE bands. Some 5G bands reuse the same frequencies as existing LTE bands but in the NR numbering scheme. Q: Do bands differ between regions? A: Yes. Spectrum allocation is set by national regulators, so a phone sold in Europe may lack the bands a US carrier uses. Band 71 is US-only, band 20 (800 MHz) is mainly European, and band 28 (700 MHz APT) covers Asia-Pacific and parts of Europe. Q: What is a band's centre frequency used for? A: The frequency range determines propagation: lower bands (700-900 MHz) travel far and penetrate buildings well, while higher bands (2.6 GHz, 3.5 GHz) carry more capacity over shorter range. Carriers layer them for coverage plus capacity. Q: Is this lookup done online? A: No. The full band table and search run entirely in your browser. Nothing you type is sent to a server. #### HAR to cURL Commands Converter URL: https://geratools.com/har-to-curl Free HAR to cURL converter. Load a .har export from DevTools and turn every captured request into a ready-to-run cURL command with method, headers and body, with optional URL filtering. Everything runs in your browser. How to use: 1. Export a HAR file: In your browser DevTools Network tab, choose "Save all as HAR with content" and save the .har file. 2. Load and optionally filter: Pick the file or paste the HAR JSON, then enter a URL substring to keep only matching requests. 3. Copy a cURL command: Each request becomes a cURL command; click copy and paste it into your terminal to replay the call. FAQ: Q: Does this send my HAR anywhere? A: No. The HAR is parsed locally and the cURL strings are built in JavaScript on your device. Because HAR files contain cookies and tokens, keeping everything client-side is important. Q: How does it escape the request body and headers? A: Values are wrapped in single quotes and any embedded single quote is replaced with the standard '\'' sequence so the command is shell-safe in bash and zsh. Q: Why is there a --compressed flag sometimes? A: When the original request sent an Accept-Encoding header, --compressed is added so cURL requests and transparently decodes gzip/brotli the same way the browser did. Q: Does it include the request body? A: Yes, when the HAR entry has request.postData.text it is added with a --data-raw flag. GET requests with no body produce a plain cURL command. Q: Will cookies be included? A: If the captured request carried a Cookie header it is emitted as a -H 'Cookie: …' flag. Be careful: that command then contains your live session, so treat it as a secret. #### Helm Template Functions Reference URL: https://geratools.com/helm-template-functions Searchable Helm and Sprig template function reference covering string, dict, list, math, encoding and flow functions with signature and example. Build correct Helm chart templates fast. How to use: 1. Search for a function: Type a function name or keyword like quote, default, nindent, or toYaml to filter the reference. 2. Filter by category: Use the category dropdown to view String, Flow, List, Dict, Math, Encoding, Indent, or Helm-only functions. 3. Try it live: Pick a function in the playground, enter an input string, and see the transformed result before using it in your chart. FAQ: Q: What is the difference between Helm functions and Sprig functions? A: Sprig is the upstream Go template function library that supplies most string, list, math and encoding helpers. Helm adds a handful of chart-specific functions on top, such as include, tpl, required, lookup and the Files object, which are not part of Sprig. Q: How do I render a value as a quoted YAML string? A: Pipe it through quote, for example {{ .Values.name | quote }} produces a double-quoted string. Use squote for single quotes. Always quote user-supplied strings so values that look like numbers or booleans are not misinterpreted by the YAML parser. Q: When should I use include instead of template? A: include returns the rendered output as a string so you can pipe it into functions like indent or nindent, which template cannot do because it writes directly to output. Prefer include for any named template whose result needs further processing. Q: What does the required function do? A: required "message" .Value fails the render with the given error message if the value is empty or nil, otherwise it returns the value. It is the standard way to enforce that a chart user has supplied a mandatory configuration value. Q: Why use nindent instead of indent? A: nindent prepends a newline before indenting every line by the given number of spaces, which is convenient when embedding a multi-line block after a YAML key. indent only adds spaces without the leading newline, so you often combine it with a manual newline. #### HTTP Alt-Svc & Upgrade Reference URL: https://geratools.com/http-alt-svc-header Reference for HTTP protocol-upgrade headers including Upgrade, Alt-Svc, ALPN and 101 Switching Protocols, plus a live Alt-Svc parser that splits entries into protocol, authority and max-age. How to use: 1. Paste an Alt-Svc value: Enter an Alt-Svc header and the parser splits it into its alternative-service entries. 2. Read each alternative: See the protocol (h2, h3), the target authority and the max-age the client should remember it for. 3. Cross-check the table: Use the header table to understand how Upgrade, Connection and ALPN relate to protocol negotiation. FAQ: Q: What does the Alt-Svc header do? A: Alt-Svc advertises alternative endpoints or protocols that serve the same origin — typically HTTP/3 over QUIC. The client may switch to the advertised service on its next request and remember it for the ma (max-age) duration, defaulting to 24 hours. Q: How does an HTTP Upgrade work? A: The client sends Upgrade: together with Connection: Upgrade. If the server agrees it replies 101 Switching Protocols and both sides continue over the new protocol on the same TCP connection. This is how WebSocket connections are established. Q: What does h3=":443" mean in Alt-Svc? A: It advertises HTTP/3 (h3) reachable on port 443 of the same host — the empty host before the colon means reuse the current origin's host. h2="alt.example:443" would point HTTP/2 at a different host and port. Q: Is HTTP2-Settings still used? A: Rarely. HTTP2-Settings carried a base64url SETTINGS frame for cleartext HTTP/2 (h2c) upgrades. Browsers never adopted h2c and negotiate HTTP/2 and HTTP/3 via TLS ALPN instead, so the header is effectively legacy. Q: Does this tool send my header anywhere? A: No. Alt-Svc parsing happens entirely in your browser with JavaScript. Nothing is uploaded, logged or stored. #### HTTP Digest Auth Parameters URL: https://geratools.com/http-digest-auth-reference Reference for HTTP Digest Authentication WWW-Authenticate and Authorization header parameters with the MD5/SHA-256 response algorithm and a live response digest computer. How to use: 1. Read the challenge parameters: Review the WWW-Authenticate parameters the server sends — realm, nonce, qop, algorithm and opaque. 2. Map the response fields: See which fields the client returns in Authorization, including username, uri, nc, cnonce and the computed response. 3. Compute a digest: Enter the credentials and challenge values to compute HA1, HA2 and the final response hash with the right qop formula. FAQ: Q: How is the Digest response computed? A: With qop=auth the response is H(HA1:nonce:nc:cnonce:qop:HA2), where HA1 = H(username:realm:password) and HA2 = H(method:digestURI). H is the hash named by the algorithm parameter (MD5 by default, or SHA-256). Without qop the simpler legacy form H(HA1:nonce:HA2) is used. Q: What is the nonce and why does it change? A: The nonce is a server-generated opaque value sent in the WWW-Authenticate challenge. It is mixed into the response hash so a captured response cannot be replayed indefinitely. Servers rotate the nonce and may mark a stale one with stale=true, prompting the client to recompute without re-asking for a password. Q: What do nc and cnonce do? A: When qop is present the client adds a client nonce (cnonce) and a nonce count (nc) — an 8-hex counter of how many times it has used this server nonce. They let the server detect replays and let the client contribute randomness, strengthening the digest against precomputed-table attacks. Q: Is Digest auth secure? A: It avoids sending the password in cleartext (unlike Basic) and resists simple replay, but MD5 Digest is weak by modern standards and offers no body integrity by default. RFC 7616 added SHA-256 and qop=auth-int, but Digest should still only be used over TLS; prefer token-based auth for new systems. Q: What is qop=auth versus qop=auth-int? A: qop=auth (authentication) protects only the request method and URI. qop=auth-int (authentication with integrity) also hashes the request body into HA2 as H(method:digestURI:H(entityBody)), protecting the payload from tampering at the cost of buffering the whole body. #### HTTP Range Request Reference URL: https://geratools.com/http-range-header-reference Reference for HTTP byte-range request headers with multi-part range syntax and server support notes, plus a live parser that resolves each range against a resource size and shows the 206 or 416 outcome. How to use: 1. Enter a resource size: Type the total size of the resource in bytes so the parser can resolve each range against it. 2. Paste a Range value: Enter a Range header like bytes=0-499, -200 and the tool resolves every range spec, including suffix and open-ended ranges. 3. Read the outcome: See whether the server would answer 206 Partial Content with a Content-Range, or 416 Range Not Satisfiable for out-of-bounds ranges. FAQ: Q: Are byte ranges inclusive? A: Yes. Both the first and last positions are inclusive and zero-based, so bytes=0-499 requests the first 500 bytes. The number of bytes returned is last − first + 1. Q: What is a suffix range? A: A range written as bytes=-N (no first position) requests the final N bytes of the resource. For a 1000-byte file, bytes=-200 returns bytes 800 through 999. It is handy when you do not know the total size in advance. Q: When does a server return 416? A: 416 Range Not Satisfiable is returned when the first position is at or beyond the resource size, or every requested range is invalid. The response should include a Content-Range: bytes */ header stating the actual size. Q: What is Accept-Ranges for? A: On a normal 200 response the server sends Accept-Ranges: bytes to advertise that it supports byte-range requests, or Accept-Ranges: none to say it does not. Clients use it to decide whether resumable or chunked downloads are possible. Q: Does this tool send my header anywhere? A: No. Range parsing and resolution happen entirely in your browser with JavaScript. Nothing is uploaded, logged or stored. #### HTTP/2 Server Push Reference URL: https://geratools.com/http-server-push-reference Reference for HTTP/2 Server Push: the PUSH_PROMISE frame, RST_STREAM cancellation, the SETTINGS_ENABLE_PUSH flag, why browsers removed it, and 103 Early Hints with rel=preload as the modern replacement. How to use: 1. Search the topic: Type a frame name, setting or keyword like PUSH_PROMISE, RST_STREAM, Early Hints or preload. 2. Read the mechanic: Each entry explains one piece of the push lifecycle or a fact about its deprecation and replacement. 3. Adopt the modern path: Use the 103 Early Hints and Link rel=preload entries to migrate off Server Push, which browsers no longer support. FAQ: Q: Is HTTP/2 Server Push still usable? A: No, not in practice. Chrome removed support in version 106 (2022) and other engines followed, citing poor real-world performance and frequent over-pushing of already-cached resources. HTTP/3 never specified push at all. Treat it as deprecated and use 103 Early Hints instead. Q: What is a PUSH_PROMISE frame? A: PUSH_PROMISE is the frame a server sends to reserve a new stream ID and declare the request it intends to push, before sending that response's HEADERS and DATA. It carries the promised request header block so the client can match or reject the resource. Q: How does a client decline a push? A: The client sends RST_STREAM with error code CANCEL or REFUSED_STREAM on the promised stream. It can also disable push entirely by sending SETTINGS_ENABLE_PUSH = 0 in its SETTINGS frame, which most browsers now do. Q: What replaced Server Push? A: The 103 Early Hints informational status combined with Link: rel=preload headers. The server sends 103 with preload hints while it computes the final response, letting the browser start fetching critical sub-resources without the server blindly pushing bytes the client may already have cached. Q: Does HTTP/3 support push? A: No. The HTTP/3 specification (RFC 9114) deliberately omits Server Push. The industry consensus settled on 103 Early Hints as the forward-compatible mechanism for hinting critical resources early. #### ICD-10 Chapter Reference URL: https://geratools.com/icd10-chapter-reference Reference table of all 22 ICD-10-CM chapters with their alphanumeric code ranges and disease categories, plus a code-to-chapter lookup. Filter by keyword or range for fast medical coding lookups. #### ICMP Type & Code Reference URL: https://geratools.com/icmp-type-codes Searchable ICMP message reference covering both ICMPv4 (RFC 792) and ICMPv6 (RFC 4443) type and code pairs, with diagnostic use cases for ping, traceroute, Path MTU Discovery and Neighbor Discovery. Bundled offline. How to use: 1. Search a type or keyword: Enter a type number like 8, or a keyword such as unreachable, traceroute or redirect. 2. Filter by IP version: Switch between ICMPv4, ICMPv6 or both to find the right message for your stack. 3. Read the diagnostic note: Each row explains the type and code pair and where you would see it — for example type 3 code 4 driving Path MTU Discovery. FAQ: Q: What ICMP type is a ping? A: A ping uses ICMPv4 type 8 (Echo Request) and the reply is type 0 (Echo Reply). In IPv6 the equivalents are type 128 and type 129 respectively. Q: Why must I not block all ICMP on IPv6? A: IPv6 routers never fragment, so they rely on ICMPv6 type 2 (Packet Too Big) for Path MTU Discovery, and on Neighbor Discovery messages (types 133–137) for address resolution and autoconfiguration. Blocking these breaks connectivity rather than hardening it. Q: How does traceroute use ICMP? A: Traceroute sends packets with increasing TTL (hop limit). Each router that decrements the value to zero returns ICMP Time Exceeded (type 11 in v4, type 3 in v6), revealing that hop. The final host typically returns Port Unreachable or an Echo Reply. Q: What is ICMP type 3 code 4 and why does it matter? A: It is Destination Unreachable: Fragmentation Needed with the Don't Fragment bit set. It is the core signal of IPv4 Path MTU Discovery; firewalls that silently drop it cause PMTU black holes where large packets vanish. Q: Is Source Quench still used? A: No. ICMP Source Quench (type 4) was a congestion-control signal that RFC 6633 formally deprecated. Modern hosts neither send nor act on it, relying on TCP congestion control instead. #### Igneous Rock Classification Reference URL: https://geratools.com/igneous-rock-reference Reference table of common igneous rocks classified by silica content (felsic to ultramafic) and grain size (intrusive vs extrusive), with mineralogy and a composition-plus-texture classifier. How to use: 1. Choose a composition: Select felsic, intermediate, mafic or ultramafic to set the silica content of the rock. 2. Choose a texture: Pick coarse intrusive or fine extrusive to set how quickly the magma cooled. 3. Read the match: See the common igneous rock that fits your composition and texture, with its silica range, minerals and formation note. FAQ: Q: How are igneous rocks classified? A: Mainly by two axes: chemical composition, judged by silica content from felsic (silica-rich) to ultramafic (silica-poor), and texture, judged by grain size. Coarse grains mean slow cooling at depth, fine grains mean rapid cooling at the surface. Q: What is the difference between intrusive and extrusive? A: Intrusive (or plutonic) rocks crystallise slowly underground, giving large interlocking crystals you can see, like granite. Extrusive (or volcanic) rocks cool quickly at the surface, giving fine or glassy textures, like basalt and rhyolite. Q: What does felsic and mafic mean? A: Felsic rocks are rich in silica and light-coloured minerals such as quartz and feldspar, so they are pale and low density. Mafic rocks are silica-poor and rich in magnesium and iron minerals, so they are dark and denser. Ultramafic rocks are the most magnesium- and iron-rich of all. Q: What are granite and basalt's extrusive and intrusive twins? A: Granite, a coarse felsic rock, has the fine-grained rhyolite as its extrusive twin. Basalt, a fine mafic rock, has the coarse-grained gabbro as its intrusive twin. Each composition pairs a slow-cooled and a fast-cooled rock of matching chemistry. Q: Why is basalt so common? A: Basalt is the most abundant volcanic rock because it makes up the bulk of the oceanic crust and erupts from mid-ocean ridges, hotspots and flood-basalt provinces. Its low-silica magma is runny and erupts readily across the planet. #### IMDG / IMO Class to UN Class Cross-Reference URL: https://geratools.com/imco-class-to-un-class Reference table mapping IMO IMDG hazard classes and divisions to UN dangerous goods class numbers for maritime transport. Filter by class, division, or hazard to find the matching UN class, hazard name, and example substances. How to use: 1. Search a class: Type a class number, a division like 4.3, or a hazard word such as corrosive to filter the table. 2. Read the mapping: Each entry shows the IMDG class and division alongside the matching UN class number. 3. Check the examples: Use the hazard name and example substances to confirm the class for your cargo. FAQ: Q: How do IMDG classes relate to UN dangerous goods classes? A: The IMO adopted the United Nations dangerous goods class system, so the class numbers are the same. An IMDG Class 3 substance is also UN Class 3. The IMDG Code adds maritime-specific detail such as divisions, packing groups, and segregation rules for carriage by sea. Q: What are the nine main dangerous goods classes? A: Class 1 explosives, Class 2 gases, Class 3 flammable liquids, Class 4 flammable solids and reactive substances, Class 5 oxidisers and organic peroxides, Class 6 toxic and infectious substances, Class 7 radioactive material, Class 8 corrosives, and Class 9 miscellaneous dangerous substances and articles. Q: What do the division numbers like 2.1 or 4.3 mean? A: Some classes are split into divisions for more specific hazards. Class 2 divides into 2.1 flammable gas, 2.2 non-flammable non-toxic gas, and 2.3 toxic gas. Class 4 divides into 4.1 flammable solids, 4.2 spontaneously combustible, and 4.3 dangerous when wet. Q: What is the difference between IMCO and IMO? A: IMCO, the Inter-Governmental Maritime Consultative Organization, was the former name of the body now called the IMO, the International Maritime Organization. The IMDG Code is its set of rules for carrying dangerous goods by sea, so IMCO class and IMDG class refer to the same scheme. Q: Which class covers lithium batteries? A: Lithium batteries are assigned to Class 9, miscellaneous dangerous goods. Class 9 covers substances and articles that present a danger during transport not covered by the other classes, which also includes dry ice, marine pollutants, and asbestos. #### IMF SDR Basket Reference URL: https://geratools.com/imf-sdr-basket-reference Reference table of the IMF SDR currency basket composition — US dollar, euro, renminbi, yen, and pound sterling — with their official weights, currency amounts, and the five-yearly review schedule. How to use: 1. Open the basket table: The tool loads the five SDR basket currencies with their official weights from the latest IMF review. 2. Filter or sort: Type a currency name or code to filter, or click a column header to sort by weight or amount. 3. Read the weights: Each row shows the weight percentage and the fixed currency amount used to compute the daily SDR value. FAQ: Q: What currencies are in the SDR basket? A: Five currencies: the US dollar, the euro, the Chinese renminbi, the Japanese yen, and the pound sterling. The renminbi was added in 2016, making it the first emerging-market currency in the basket. Q: What are the current SDR weights? A: From the 2022 review: US dollar 43.38%, euro 29.31%, renminbi 12.28%, yen 7.59%, and pound sterling 7.44%. Weights reflect the role of each currency in international trade and finance. Q: How often is the basket reviewed? A: The IMF reviews the SDR basket every five years. The 2022 review took effect 1 August 2022, and the next regular review is scheduled for 2027 unless economic conditions trigger an earlier one. Q: How is the daily SDR value calculated? A: Each currency contributes a fixed amount (not a fixed weight) to the basket. The IMF multiplies these fixed amounts by daily exchange rates against the dollar and sums them, so the live weights drift slightly from the review-date weights. Q: Is the SDR a currency I can spend? A: No. The SDR is a unit of account and an international reserve asset held by IMF member countries, not a circulating currency. It can be exchanged among members for freely usable currencies. #### International Postage Zone Reference URL: https://geratools.com/international-postage-zone-reference Reference for Royal Mail international zones (Europe, World Zone 1, 2, 3) and USPS price groups 1 to 9, with a country lookup that maps each destination to its carrier zone for parcel pricing. How to use: 1. Look up a country: Type a destination country to see its Royal Mail zone and USPS price group side by side. 2. Read the zone definitions: Scroll to the carrier sections for the full list of zones and the kinds of countries each one covers. 3. Confirm before posting: Use the zone to estimate pricing, then check the carrier's live rate card as zones and prices change. FAQ: Q: How does Royal Mail group international destinations? A: Royal Mail uses a Europe Zone plus World Zones 1, 2 and 3. Europe covers EU and nearby countries, World Zone 1 covers the USA, Canada, Africa, the Middle East and most of Asia, and World Zones 2 and 3 cover Australia, New Zealand and parts of the Pacific on certain services. Q: What are USPS price groups? A: USPS assigns every country to a Price Group from 1 to 9, each with its own rate. Group 1 is Canada, Group 2 is Mexico, and the higher groups cover Europe, South America, Asia and Oceania. The price you pay depends on the group and the service. Q: Why is the same country in different zones for each carrier? A: Royal Mail and USPS build their zones independently around their own networks and costs, so a destination like Japan can sit in Royal Mail World Zone 2 but USPS Price Group 9. Always read each carrier's own map. Q: Are these zones fixed? A: No. Carriers revise zone membership and pricing periodically, and some services use a slightly different grouping. Treat this as a guide and confirm the current zone on the carrier's official rate card before posting. Q: Does this tool use the internet? A: No. The zone tables are bundled with the page and all lookups run in your browser. Nothing is uploaded, logged or stored. #### IntersectionObserver Options Reference URL: https://geratools.com/intersection-observer-options Reference for IntersectionObserver constructor options — root, rootMargin and threshold — plus every IntersectionObserverEntry property and a live rootMargin validator for lazy-loading and scroll triggers. How to use: 1. Validate a rootMargin: Type a rootMargin value and the tool confirms whether each token is a valid px or % length in the correct order. 2. Read the options: Review root, rootMargin and threshold with their types and defaults to configure the observer. 3. Use the entry properties: Check the IntersectionObserverEntry properties to read visibility ratios and rectangles inside your callback. FAQ: Q: What does the threshold option do? A: threshold sets the visibility ratio(s) at which the callback fires. A value of 0 fires as soon as a single pixel is visible, 1 fires only when the target is fully visible, and an array such as [0, 0.5, 1] fires at each step, letting you react to partial visibility. Q: How does rootMargin work? A: rootMargin grows or shrinks the root's bounding box before intersection is computed, using CSS margin syntax in top right bottom left order. Positive values expand the box to trigger earlier; negative values shrink it to trigger later, which is ideal for preloading just before content scrolls in. Q: What is intersectionRatio? A: intersectionRatio is a number from 0 to 1 reported on each IntersectionObserverEntry, giving the fraction of the target's bounding box currently visible within the root. It lets you drive animations or analytics on how much of an element is on screen. Q: Why use IntersectionObserver instead of scroll events? A: IntersectionObserver runs asynchronously off the main thread and batches its callbacks, so it avoids the layout thrashing and jank caused by handling high-frequency scroll events. It is the recommended way to do lazy-loading, infinite scroll and visibility tracking. Q: Does this tool observe anything on the page? A: No. It is a static reference plus a string validator. It does not create a real observer, and nothing is uploaded or stored. #### iOS Info.plist Keys Reference URL: https://geratools.com/ios-info-plist-keys Searchable iOS Info.plist key reference covering bundle identity keys, UI configuration, and the permission usage-description (NSxUsageDescription) strings App Review requires before granting access to camera, location, photos and more. How to use: 1. Filter by group: Choose bundle, UI or usage-description to focus on the kind of Info.plist key you need. 2. Search a key: Type a key name or capability to find the exact Info.plist key and its value type. 3. Add the key: Add the key to Info.plist with the right type; for permission keys write a clear, specific usage string. FAQ: Q: What is an NSxUsageDescription key? A: It is a privacy usage-description string explaining why your app needs a protected resource such as the camera or location. iOS shows this text in the permission prompt, and App Review rejects builds that access the resource without the corresponding key set. Q: What is the difference between CFBundleShortVersionString and CFBundleVersion? A: CFBundleShortVersionString is the public marketing version users see, like 2.1.0. CFBundleVersion is the build number, an internal counter that must increase with every upload to App Store Connect even if the marketing version stays the same. Q: Which keys are required for every app? A: CFBundleIdentifier, CFBundleShortVersionString, CFBundleVersion and CFBundleExecutable are required, and most apps also set CFBundleDisplayName and UILaunchStoryboardName. Xcode populates several automatically from build settings. Q: What happens if I request a permission without its usage key? A: The app crashes at runtime the moment it accesses the resource, because iOS deliberately terminates apps that touch protected data without a declared purpose string. Always pair an API like the camera with its NSCameraUsageDescription key. Q: Where do I edit Info.plist in modern Xcode? A: Recent Xcode projects manage many keys under the target's Info tab and build settings rather than a standalone file, but you can still add custom and usage-description keys there. Expo and React Native projects often set them via app.json or config plugins. #### Historic Currency Code Reference URL: https://geratools.com/iso4217-historic-currency-reference Searchable reference of retired ISO 4217 currency codes — the German Mark, French Franc, Greek Drachma and more — with numeric code, country, withdrawal year and the currency that replaced each one. How to use: 1. Search the table: Type a retired three-letter code, currency name, country or successor currency to filter the list instantly. 2. Read the replacement: Each row shows the year the code was withdrawn and the ISO 4217 code that replaced it, such as EUR or RON. 3. Use the numeric code: The numeric ISO 4217 identifier is shown alongside each alphabetic code for systems that key on numbers. FAQ: Q: Why are old currency codes still listed by ISO 4217? A: ISO 4217 keeps withdrawn codes on a reserved list so historic transactions, archives and ledgers remain unambiguous. The code is retired from active use but never silently reassigned to a different currency. Q: What replaced the Deutsche Mark and French Franc? A: Both were replaced by the euro (EUR) when euro banknotes and coins entered circulation on 1 January 2002. Their DEM and FRF codes were withdrawn at that point but remain valid for historic reference. Q: When did Croatia switch to the euro? A: Croatia adopted the euro on 1 January 2023, withdrawing the kuna (HRK). It is the most recent eurozone accession and the newest code on this list. Q: What is the ECU code XEU? A: XEU was the European Currency Unit, a basket-based accounting unit used by the EU before the euro. It was replaced one-for-one by the euro (EUR) on 1 January 1999 when the euro became the official accounting currency. Q: Does this tool connect to the internet? A: No. The full table is bundled with the page and all searching happens in your browser. Nothing is uploaded, logged or stored. #### jq Filter Reference URL: https://geratools.com/jq-filter-reference Searchable jq reference covering identity, field and index access, pipes, the comma, object/array construction, conditionals, reduce, and the most-used built-in functions like map, select, keys, length and to_entries. How to use: 1. Search the filters: Type a filter or keyword such as "map" or "select" to filter the jq reference of operators and built-ins. 2. Read the example: Each entry shows the jq expression, sample input/output and a description of what it does to the stream of JSON values. 3. Compose a pipeline: Chain filters with the pipe | so each stage transforms the output of the previous one into the final result. FAQ: Q: What is the jq identity filter? A: The identity filter is a single dot (.) and returns its input unchanged. It is the simplest filter and the starting point of most pipelines — for example, .name reads the name field of the input, where the leading dot is the identity that the field access applies to. Q: What is the difference between map and select in jq? A: map(f) applies the filter f to every element of an array and collects the results into a new array, transforming each item. select(cond) is a filter that outputs its input only if the condition is true, otherwise nothing — it is used to keep or drop items, often inside map, as in map(select(.age > 18)). Q: How does the pipe operator work in jq? A: The pipe | feeds the output of the filter on its left as the input to the filter on its right, like a Unix shell pipe. So .users | length first selects the users array, then counts it. Pipelines can be as long as needed, each stage transforming the stream. Q: What does the comma operator do in jq? A: The comma runs several filters on the same input and concatenates all their outputs into one stream. For example, .a, .b emits the value of a followed by the value of b. It is how you produce multiple results from a single input. Q: How do I iterate over an array in jq? A: The array/object value iterator .[] produces each element of an array (or each value of an object) as a separate output in the stream. Combine it with select to filter, as in .[] | select(.active), or wrap a pipeline in [ ... ] to collect the results back into an array. #### JavaScript Intl API Reference URL: https://geratools.com/js-intl-api-reference Searchable reference for the JavaScript Intl API — DateTimeFormat, NumberFormat, RelativeTimeFormat, ListFormat, PluralRules and Collator — with a live formatter that runs each constructor in your browser for any locale and options. How to use: 1. Pick a formatter: Choose Intl.NumberFormat, DateTimeFormat, RelativeTimeFormat, ListFormat or PluralRules from the list. 2. Set a locale and value: Enter a BCP 47 locale such as de-DE or ar-EG and a value, then adjust the style option. 3. Read the live output: The tool runs the real Intl constructor in your browser and shows the formatted result, so you can verify behaviour before coding. FAQ: Q: What is the difference between Intl.NumberFormat styles? A: The style option selects what is formatted: 'decimal' for plain numbers, 'currency' (requires a currency code) for money, 'percent' which multiplies by 100 and adds a percent sign, and 'unit' (requires a unit) for measurements like kilometers. Each respects the locale's grouping and decimal separators. Q: Why does Intl.PluralRules return 'one' for some non-1 numbers? A: Plural categories are language-specific, not just singular vs plural. English uses only 'one' and 'other', but Arabic has six categories (zero, one, two, few, many, other) and Polish distinguishes 'few' and 'many'. PluralRules returns the CLDR category so you can pick the correct message form. Q: How do I format relative times like '3 days ago'? A: Use Intl.RelativeTimeFormat: new Intl.RelativeTimeFormat('en', { numeric: 'auto' }).format(-3, 'day') gives '3 days ago', and format(1, 'day') gives 'tomorrow'. The numeric:'auto' option enables idiomatic words like yesterday/tomorrow instead of always saying '1 day ago'. Q: What does Intl.Collator do that String.localeCompare does not? A: Intl.Collator is the configurable engine behind localeCompare. Creating one Collator and reusing its compare function is faster for sorting large arrays, and it exposes options like sensitivity (base/accent/case), numeric (so 'a2' sorts before 'a10') and caseFirst that you cannot set as conveniently otherwise. Q: Are Intl constructors expensive to create? A: Yes, relatively — building a formatter loads locale data and is far slower than calling .format(). Create the formatter once and reuse it across many values rather than constructing a new one inside a loop. The output of this tool is computed in your browser using the same constructors. #### JavaScript Temporal API Reference URL: https://geratools.com/js-temporal-api-reference Reference for the TC39 Temporal proposal — PlainDate, PlainDateTime, ZonedDateTime, Instant, PlainTime, Duration and PlainYearMonth — with what each type represents, when to use it, and how it fixes the legacy Date pitfalls. How to use: 1. Search the type: Type a type name like ZonedDateTime, PlainDate or Duration, or a keyword such as timezone or immutable. 2. Read what it models: Each entry states exactly what the type represents and the key creation and arithmetic methods. 3. Choose the right type: Use the guidance to pick PlainDate for wall dates, ZonedDateTime for time-zone-aware moments, and Instant for exact UTC timestamps. FAQ: Q: Why does JavaScript need Temporal when it already has Date? A: Date has well-known flaws: it is mutable, it only models a single instant yet exposes confusing local-vs-UTC accessors, months are zero-indexed, parsing is inconsistent across engines, and it has no real time-zone or calendar support. Temporal replaces it with immutable, purpose-specific, clearly-named types and reliable ISO 8601 parsing. Q: What is the difference between Instant and ZonedDateTime? A: Temporal.Instant is an exact point on the global timeline (like a UTC timestamp) with no time zone or calendar attached. Temporal.ZonedDateTime is that same instant interpreted in a specific time zone and calendar, so it knows the local wall-clock time, the UTC offset, and how to handle DST transitions. Q: When should I use PlainDate versus PlainDateTime? A: Use Temporal.PlainDate for a calendar date with no time or zone, like a birthday or invoice date. Use Temporal.PlainDateTime when you also need a wall-clock time but still no time zone, such as '2026-06-06 09:00' in an unspecified location. Add a time zone only when you need ZonedDateTime. Q: How does Temporal handle daylight saving time? A: ZonedDateTime is DST-aware. Adding 'one day' across a spring-forward boundary yields the same wall-clock time the next day even though only 23 hours elapsed, whereas adding a Duration of 24 hours adds exactly 24 hours of real time. The disambiguation option controls what happens for skipped or repeated local times. Q: Are Temporal objects mutable? A: No. Every Temporal type is immutable. Methods like add, subtract, with and round return a brand-new object rather than changing the original, which eliminates a whole class of aliasing bugs that plagued the mutable Date object. #### Key Derivation Function Reference URL: https://geratools.com/kdf-algorithm-reference Reference for password hashing and key derivation functions including Argon2, scrypt, bcrypt, PBKDF2 and HKDF with cost parameters, memory hardness and OWASP-aligned tuning guidance. How to use: 1. Search functions: Type Argon2, bcrypt or PBKDF2 to filter the key-derivation table. 2. Filter by use: Use the dropdown to separate password hashing from key-extraction KDFs. 3. Read the parameters: Check the recommended cost column for current OWASP-aligned tuning values. FAQ: Q: Which KDF should I use for password hashing in 2026? A: Argon2id is the first-choice modern password hash because it is memory-hard, resisting GPU and ASIC attacks. If Argon2 is unavailable, scrypt and bcrypt are acceptable, and PBKDF2 with a high iteration count is the FIPS-friendly fallback. Q: How many PBKDF2 iterations are enough? A: OWASP guidance recommends at least 600,000 iterations for PBKDF2-HMAC-SHA-256. Iterations only raise CPU cost, not memory, so PBKDF2 is weaker against GPU attacks than memory-hard functions like Argon2. Q: What does memory-hard mean? A: A memory-hard KDF deliberately uses a large block of RAM so attackers cannot cheaply parallelise guesses on GPUs or custom ASIC hardware. Argon2 and scrypt are memory-hard; bcrypt is mildly so; PBKDF2 is not. Q: Is HKDF a password hash? A: No. HKDF derives one or more cryptographic keys from an already-high-entropy secret, such as a Diffie-Hellman shared secret. It is fast by design and must not be used to hash low-entropy passwords. Q: Why does each password need a unique salt? A: A per-password random salt prevents precomputed rainbow-table attacks and ensures two users with the same password get different hashes. The salt is stored alongside the hash and need not be secret. #### kubectl Cheatsheet URL: https://geratools.com/kubernetes-kubectl-cheatsheet Searchable kubectl cheatsheet covering get, describe, apply, delete, exec, logs, rollout, scale and config commands — each with the real flags, a plain-English explanation and a copy button. How to use: 1. Filter by verb: Pick a group such as logs or rollout to narrow the list to one category of commands. 2. Search: Type any keyword like "port-forward" or "namespace" to find the exact command. 3. Copy: Click Copy to put the command on your clipboard, then replace the placeholders. FAQ: Q: How do I follow logs from a crashing pod? A: Use kubectl logs -f POD to stream live logs. If the container already crashed and restarted, add --previous to read the logs from the prior instance, which usually contains the crash cause. Q: What is the difference between apply and create? A: kubectl apply is declarative: it creates resources that do not exist and patches ones that do, tracking the desired state. kubectl create is imperative and fails if the object already exists. Prefer apply for GitOps-style workflows. Q: How do I roll back a bad deployment? A: Run kubectl rollout undo deploy/NAME to revert to the previous revision. Use kubectl rollout history deploy/NAME first to inspect revisions, and rollout status to watch the rollback complete. Q: How do I run a shell inside a pod? A: Use kubectl exec -it POD -- sh (or bash if available). The -it flags attach stdin and a TTY. For a multi-container pod add -c CONTAINER to choose which container to enter. Q: How do I change my default namespace? A: Run kubectl config set-context --current --namespace=NS. This avoids typing -n on every command. Use kubectl config get-contexts to see your current context and namespace. #### Language Family Reference URL: https://geratools.com/language-family-reference Searchable reference of the world's major language families — Indo-European, Sino-Tibetan, Niger-Congo, Afro-Asiatic and more — each with representative member languages, approximate first-language speaker totals, and the region where it is spoken. How to use: 1. Search a family or language: Type a family name, a specific language such as Swahili, or a region to filter the table. 2. Read the members: The representative languages column lists the best-known languages that belong to each family. 3. Check the scale: Use the approximate first-language speaker total to compare how large each family is worldwide. FAQ: Q: What is a language family? A: A language family is a group of languages descended from a common ancestor language, related the way English, Hindi, and Russian all descend from Proto-Indo-European. Membership is established by systematic sound correspondences and shared grammar, not just borrowed words. Q: Which language family is the largest? A: Indo-European has the most first-language speakers, around 3.2 billion, because it includes English, Spanish, Hindi-Urdu, Russian, Portuguese, and Bengali among many others. Sino-Tibetan is second, led by Mandarin Chinese. Q: What is a language isolate? A: A language isolate is a language with no demonstrated relatives, forming a family of one. Basque, spoken in the western Pyrenees, is the classic European example and is unrelated to any neighbouring language. Q: Are these speaker numbers exact? A: No. They are rounded first-language (L1) estimates drawn from standard sources such as Ethnologue. Counts vary between sources, exclude many second-language speakers, and shift year to year, so treat them as orders of magnitude. Q: Why are some big languages missing? A: The table lists families and a few representative members, not every language. Languages like Italian, Polish, or Marathi are present through their family (Indo-European) even when not named in the short member list. #### BCP 47 Language Tag Reference URL: https://geratools.com/language-tag-reference Reference for IETF BCP 47 language tags: primary language, script, region, variant and extension subtags, their syntax rules, ordering, and worked examples like zh-Hans-CN and en-US-u-ca-gregory. How to use: 1. Search a subtag: Type a code like "Latn" or a word like "script" or "Armenia" to filter the subtag table. 2. Filter by subtag type: Switch between language, script, region, variant and extension to see only that class of subtag. 3. Read the example tag: Each row shows a complete BCP 47 tag using that subtag so you can see correct ordering and casing. FAQ: Q: What is the correct order of subtags in a BCP 47 language tag? A: The canonical order is language-Script-REGION-variant-extension-privateuse, for example zh-Hans-CN or de-1996. Language is lowercase, script is Title-case, region is UPPERCASE, and variants/extensions follow. Q: When should I include a script subtag like Hans or Cyrl? A: Include a script subtag only when it adds information the language subtag does not already imply. zh-Hans versus zh-Hant is meaningful, but en-Latn is redundant since English is suppress-script Latin in the registry. Q: What is the difference between a region and a variant subtag? A: A region subtag is an ISO 3166-1 alpha-2 code (UPPERCASE, like US) or a UN M.49 three-digit number (like 419 for Latin America). A variant subtag (5-8 alphanumerics, or 4 starting with a digit, like 1996 or valencia) marks a dialect or orthography. Q: What do the u, t and x extension singletons mean? A: The 'u' singleton carries Unicode locale extensions such as calendar or collation (en-US-u-ca-gregory). The 't' singleton marks transformed/transliterated content. The 'x' singleton starts a private-use sequence with no registered meaning. Q: What are grandfathered tags? A: Grandfathered tags like i-klingon or zh-min-nan were registered before the current syntax and remain valid for compatibility. Most have a preferred modern replacement (tlh, nan) that you should use in new content. #### LDAP Result Codes Reference URL: https://geratools.com/ldap-result-codes Searchable reference for LDAP result codes from RFC 4511 and the Cancel extension (RFC 3909). Look up any code by number or name, see whether it is success, referral or error, and read the likely cause. How to use: 1. Search by code or name: Type a number like 49, a name like invalidCredentials, or a keyword like password. The list filters instantly. 2. Filter by category: Use the category selector to narrow to success, referral or error result codes. 3. Read the cause and source: Each row shows the plain-English cause and the RFC that defines the code, plus a copy button for your notes. FAQ: Q: What does LDAP result code 49 mean? A: Result code 49 is invalidCredentials. It means the bind DN or password was wrong, or the account is locked, disabled or expired. Active Directory often appends a sub-code (like 52e for bad password or 533 for a disabled account) in the diagnostic message. Q: Is result code 0 an error? A: No. Code 0 is success, meaning the operation completed normally. Several other non-error codes also exist, such as 5 (compareFalse), 6 (compareTrue) and 14 (saslBindInProgress), which appear in normal protocol flows rather than failure paths. Q: What is the difference between code 32 and code 34? A: Code 32 is noSuchObject, meaning the target entry DN does not exist in the directory. Code 34 is invalidDNSyntax, meaning the DN string itself is malformed and could not even be parsed. One is a missing entry, the other is a bad name. Q: Which RFC defines LDAP result codes? A: The core set is defined in RFC 4511, the LDAPv3 protocol specification, in section 4.1.9 and Appendix A. The Cancel operation adds codes 118 through 121 in RFC 3909. Vendor extensions may add others outside the standard range. Q: Does this reference send my queries anywhere? A: No. The entire result-code table, search and filtering run locally in your browser with no network calls and no account. Nothing you type is uploaded. #### Legal Drinking Age by Country Reference URL: https://geratools.com/legal-drinking-age-reference Searchable reference of minimum legal drinking and alcohol purchase ages by country, split into on-premise (bars and restaurants) and off-premise (shops), with notes on beverage-strength rules and recent law changes. How to use: 1. Search a country: Type a country name to filter the table to that country. 2. Compare the two ages: Read the on-premise and off-premise columns to see if drinking in a bar and buying from a shop have different age limits. 3. Check the notes: The notes column flags strength-based rules, such as a lower age for beer and wine than for spirits. FAQ: Q: What is the difference between on-premise and off-premise? A: On-premise is drinking at a licensed venue such as a bar or restaurant, while off-premise is buying alcohol from a shop to drink elsewhere. Some countries set different minimum ages for the two, often allowing supervised drinking before independent purchase. Q: Why do some countries have two different ages? A: Several European countries set a lower age for low-strength drinks like beer and wine and a higher age for spirits. For example Germany allows beer and wine at 16 but spirits only at 18, reflecting a harm-reduction approach. Q: Why is the United States 21? A: A 1984 federal law tied highway funding to a minimum purchase age of 21, so all states adopted it. It is among the highest drinking ages in the world for a country where alcohol is legal. Q: Where is alcohol banned entirely? A: A number of countries prohibit alcohol for residents on religious grounds, including Saudi Arabia, Kuwait, and Libya. Some others restrict it to licensed venues for non-residents or ban it in specific provinces. Q: Is this list authoritative? A: No. It is a simplified reference. Real rules vary by region within federations, by beverage strength, and change over time. Always check current local law before relying on any age limit. #### Lighthouse Audit Categories Reference URL: https://geratools.com/lighthouse-audit-categories Searchable Lighthouse reference covering the Performance, Accessibility, Best Practices, SEO and PWA categories, the metric audit IDs, and the exact scoring weights (LCP 25%, TBT 30%, CLS 25%) that build the Performance score. How to use: 1. Search a category or audit: Type a category like accessibility or an audit ID like largest-contentful-paint to filter both reference tables at once. 2. Read the Performance weights: The weights table shows how much each lab metric contributes to the Performance score, with a bar visualizing its share. 3. Check the score bands: Use the score bands to translate any 0-100 category score into Good, Needs Improvement or Poor. FAQ: Q: What are the Lighthouse performance score weights? A: In Lighthouse 10 and 11 the Performance score is a weighted blend of five lab metrics: Total Blocking Time at 30 percent, Largest Contentful Paint and Cumulative Layout Shift at 25 percent each, and First Contentful Paint and Speed Index at 10 percent each. They sum to 100 percent. Q: Why is Total Blocking Time weighted so heavily? A: TBT is weighted at 30 percent because it is the lab proxy for responsiveness. Lighthouse runs in a lab environment where it cannot measure real interactions, so it uses main-thread blocking time between First Contentful Paint and Time to Interactive as a stand-in for the field INP metric. Q: Does Lighthouse still score PWA? A: No. PWA was removed as a scored category in Lighthouse 12. The installability and offline-related PWA audits still run but are reported as informational checks rather than contributing to a 0-100 score. The four scored categories are Performance, Accessibility, Best Practices and SEO. Q: Can Lighthouse catch every accessibility issue? A: No. Automated tools like Lighthouse can detect roughly a third of accessibility problems — things like color contrast, missing labels and invalid ARIA. The remaining issues, such as logical focus order and meaningful alt text, require manual testing with a keyboard and screen reader. Q: How are the category scores banded? A: Each category score is graded as Good for 90 to 100, Needs Improvement for 50 to 89, and Poor for 0 to 49. The colored gauge in a Lighthouse report (green, orange, red) reflects these same three bands. #### Linux System Calls Reference URL: https://geratools.com/linux-syscalls-reference Searchable Linux x86-64 system call reference covering process, file, memory, network and signal syscalls with their syscall number, C signature, return value and category. How to use: 1. Search by name or number: Type a syscall name like "mmap" or a number like "9" to jump straight to its entry. 2. Filter by category: Narrow to process, file, memory, network or signal syscalls to browse a related group. 3. Read the signature and return value: Each entry shows the C prototype, the x86-64 syscall number and what the call returns on success and error. FAQ: Q: Are these syscall numbers the same on every architecture? A: No. The numbers shown are for x86-64 (the values in the rax register). Other architectures such as ARM64, x86 (32-bit) and RISC-V use different syscall numbers, though the names and semantics are largely shared. Always check the per-arch table for portable code. Q: How does a syscall report an error? A: At the raw syscall level on x86-64, a return value between -4095 and -1 is a negated errno. The C library wrapper converts this: it returns -1 and sets the global errno variable to the positive error code, so userland code checks errno after a -1 result. Q: What is the difference between fork, vfork and clone? A: clone is the low-level primitive that creates a new task and lets you choose which resources (memory, file descriptors, namespaces) are shared via flags. fork is clone with copy-on-write memory and no sharing; vfork suspends the parent and shares memory until the child execs or exits. Threads are clone with CLONE_VM | CLONE_FILES set. Q: Why use openat instead of open? A: openat takes a directory file descriptor plus a relative path, which avoids race conditions where the directory could be swapped between resolving the path and opening the file. The *at family (openat, fstatat, unlinkat) is the modern, race-safe way to operate relative to a directory. Q: How can I see which syscalls a program makes? A: Use strace on Linux to trace syscalls and their arguments and return values in real time, for example strace -f ./program. For aggregate counts use strace -c, and for a specific syscall use -e trace=openat to filter. #### Loki Log Labels & LogQL Reference URL: https://geratools.com/loki-log-labels Searchable LogQL reference covering label matchers, line filters, label parsers, format expressions and metric queries for Grafana Loki. Build correct log queries fast. How to use: 1. Search LogQL operators: Type a keyword like json, rate, unwrap, or line filter to filter the LogQL reference. 2. Filter by pipeline stage: Use the stage dropdown to view Selector, Line filter, Parser, Label filter, Format, Metric, or Aggregation operators. 3. Assemble your query: Start with a brace stream selector, add line filters and parsers, then wrap in a range function for metrics. FAQ: Q: What is a stream selector in LogQL? A: A stream selector is the required first part of every LogQL query, written in braces, that picks which log streams to read by matching labels, e.g. {app="api", env="prod"}. At least one label matcher with the = operator is required so Loki can locate the streams. Q: What is the difference between a label matcher and a line filter? A: A label matcher in braces selects streams by indexed labels before any logs are read. A line filter like |= "error" runs after selection on the raw log line content. Label matching is fast and indexed; line filtering scans the log text. Q: How do I extract fields from JSON logs in LogQL? A: Pipe the stream through | json to parse JSON into labels, then filter or format on the extracted fields, for example {app="api"} | json | level="error". Use | logfmt for logfmt-style logs and | pattern or | regexp for custom formats. Q: How do I turn logs into a metric in LogQL? A: Wrap a log query in a range aggregation. rate({app="api"} |= "error" [5m]) gives errors per second, and count_over_time(...[1h]) gives the count in a window. You can then aggregate with sum by (label) like in PromQL. Q: Why should label cardinality be kept low in Loki? A: Each unique combination of label values creates a separate stream and index entry. High-cardinality labels such as user IDs or request IDs explode the number of streams, slow queries and bloat the index. Keep such values inside the log line and extract them at query time instead. #### Material Density Reference URL: https://geratools.com/material-density-reference Look up the density of common engineering materials — metals, alloys, plastics, woods, ceramics, and liquids — in both g/cm³ and kg/m³, and compute the mass of a part from its volume. How to use: 1. Search for a material: Type a material name — steel, aluminium, PLA, oak — to filter the table down to matching entries with their densities. 2. Read both unit systems: Each row shows density in g/cm³ and the equivalent kg/m³, so the figure drops straight into whichever formula you are using. 3. Estimate part mass: Select a material and enter a volume in cm³ to multiply by its density and read the part's mass in grams and kilograms. FAQ: Q: What is the relationship between g/cm³ and kg/m³? A: They differ by a factor of exactly 1000: 1 g/cm³ equals 1000 kg/m³. Water is 1 g/cm³ or 1000 kg/m³. The two columns are the same physical density expressed in the two common engineering unit systems. Q: How do I find a part's mass from its volume? A: Mass equals density times volume. With density in g/cm³ and volume in cm³ the answer is in grams. A 50 cm³ aluminium part at 2.70 g/cm³ weighs 50 times 2.70, which is 135 grams. Q: Why do densities vary for the same material? A: Alloy composition, temper, moisture, and porosity all shift density. Wood densities in particular depend heavily on moisture content and species, so table values are typical figures rather than exact constants. Q: Which is the densest common metal here? A: Among everyday engineering metals, lead at about 11.3 g/cm³ and gold at 19.3 g/cm³ are the densest listed, while magnesium at 1.74 g/cm³ is the lightest structural metal. Tungsten, at 19.3 g/cm³, rivals gold. Q: Can I use these for buoyancy or fluid calculations? A: Yes for a first estimate. Liquid densities here are at roughly room temperature; they fall as temperature rises, so for precise hydraulic or buoyancy work use a value at your actual operating temperature. #### METAR Abbreviation Reference URL: https://geratools.com/metar-decode-reference Searchable reference of METAR and TAF abbreviations covering sky cover (FEW, SCT, BKN, OVC, CAVOK), precipitation, obscurations, descriptors, intensity prefixes, and trend codes, with the meaning of each code grouped by category. How to use: 1. Search a code: Type a METAR abbreviation or a plain word like fog or gust to filter the code list. 2. Read the grouping: Codes are grouped by sky cover, intensity, descriptor, precipitation, obscuration, and trend so you can see how they combine. 3. Build the phrase: Combine intensity, descriptor, and phenomenon in order to decode a full weather group such as +SHRA. FAQ: Q: What do FEW, SCT, BKN, and OVC mean in a METAR? A: They describe sky cover in oktas, or eighths of the sky. FEW is 1 to 2 oktas, SCT (scattered) is 3 to 4, BKN (broken) is 5 to 7, and OVC (overcast) is a full 8 oktas. BKN and OVC layers form a ceiling, the lowest layer that obscures more than half the sky. Q: What does CAVOK mean? A: CAVOK stands for Ceiling And Visibility OK. It is reported when visibility is 10 km or more, there is no cloud below 5,000 feet or below the highest minimum sector altitude, and there is no significant weather. It is a shorthand for benign conditions. Q: How are weather phenomena built up in a METAR? A: A weather group is read left to right as intensity, then descriptor, then phenomenon. A minus sign means light and a plus sign means heavy. So +SHRA is heavy rain showers, FZFG is freezing fog, and VCTS is a thunderstorm in the vicinity of the airfield. Q: What is the difference between BR and FG? A: Both are reductions in visibility from suspended water droplets. BR is mist, reported when visibility is between 1,000 and 5,000 metres. FG is fog, reported when visibility drops below 1,000 metres. The threshold is purely the prevailing visibility. Q: Do TAF forecasts use the same codes as METAR? A: Yes. A TAF (Terminal Aerodrome Forecast) uses the same sky cover, precipitation, and obscuration codes as a METAR observation. TAFs add change groups such as BECMG for a lasting change and TEMPO for short-lived fluctuations to describe how conditions will evolve. #### Military Rank Reference URL: https://geratools.com/military-rank-reference Searchable reference of NATO officer (OF-1 to OF-10) and other ranks (OR-1 to OR-9) under STANAG 2116, with representative US, UK and German army rank titles so you can compare military ranks across nations. How to use: 1. Search or filter: Type a NATO code like OF-5 or a rank title, or use the tier filter to show only officers or other ranks. 2. Compare across nations: Each row lines up the US, UK and German army equivalents for the same NATO code so you can map one to another. 3. Mind the branch: Remember the titles shown are army examples; navy and air force use different names for the same OF or OR code. FAQ: Q: What do OF and OR mean? A: OF stands for officer and OR for other ranks (enlisted). NATO codes run OF-1 to OF-10 for commissioned officers and OR-1 to OR-9 for enlisted personnel, giving a single scale to compare ranks across member nations under STANAG 2116. Q: Why use NATO codes instead of rank names? A: Because rank titles differ wildly between nations and services. A NATO code like OF-3 unambiguously identifies the same level — Major in the US and UK armies, Major in the German army — regardless of the local name or insignia. Q: Do the same codes apply to navy and air force? A: Yes, the OF and OR scale is joint, but the titles differ by branch. OF-5 is a Colonel in the army and air force but a Captain in the navy. This table shows army equivalents as the common example. Q: What is OF-10? A: OF-10 is the highest officer code, equivalent to a five-star General of the Army or a Field Marshal. Many countries no longer use it in peacetime, which is why some columns show it as not used. Q: Does this tool use the internet? A: No. The rank table is bundled with the page and all searching and filtering run in your browser. Nothing is uploaded, logged or stored. #### MIME Type Lookup & File Extension Map URL: https://geratools.com/mime-type-lookup Free in-browser MIME type lookup. Enter a file extension to find its MIME type, or a MIME type to find its associated extensions, using a built-in registry. Bidirectional, instant and offline — no network request and nothing uploaded. How to use: 1. Type an extension or a MIME type: Enter a file extension such as png, or a full MIME type such as image/png. The presence of a slash tells the tool which direction you mean. 2. Read the match: For an extension you get the MIME type and all its registered extensions; for a MIME type you get every extension associated with it. 3. Use the correct Content-Type: Copy the MIME type into your web server config or Content-Type header so browsers handle the file correctly instead of MIME-sniffing it. FAQ: Q: How does the tool know which direction I want? A: If your input contains a slash it is treated as a MIME type (for example application/json) and the tool returns the associated extensions. Otherwise it is treated as a file extension — with or without a leading dot — and the tool returns the matching MIME type. Q: Is the lookup done online? A: No. The registry is bundled into the page, so every lookup is instant and works offline. Nothing is sent over the network and no input is logged. Q: Which MIME type should I use for JavaScript? A: For files served to browsers, text/javascript is now the standard registered type for .js and .mjs, though application/javascript still works and is widely seen. The tool notes this where relevant. Q: Why does serving the right Content-Type matter? A: Browsers may MIME-sniff a response and, for security, refuse to run a script or apply a stylesheet that is served with the wrong type. Sending the correct Content-Type header prevents broken pages and blocks a class of content-confusion attacks. Q: What if my extension is not in the registry? A: The tool covers the common web, document, image, audio, video, font and archive types. For an unknown binary file, application/octet-stream is the safe default — it tells the browser to download rather than try to render the file. #### MIME Types Lookup URL: https://geratools.com/mime-types-lookup Searchable MIME / media-type reference covering text, image, audio, video, application, font and multipart types — look up the right Content-Type by file extension or by name. How to use: 1. Type an extension or name: Enter a file extension (with or without the dot) like png or .json, or part of a media type like application/pdf. 2. Read the matches: The table shows matching media types, their canonical name, common file extensions, and the top-level category. 3. Copy the value: Click the copy button next to any media type to put the exact Content-Type string on your clipboard. FAQ: Q: What is a MIME type? A: A MIME type (also called a media type or content type) is a two-part label like text/html or image/png that tells software what kind of data a file or HTTP body contains. The first part is the top-level type and the second is the subtype. Q: Why does Content-Type matter for the web? A: Browsers and servers use the Content-Type header to decide how to handle a response — render HTML, display an image, or trigger a download. A wrong type can cause a file to display as text, fail to load, or be blocked by content-sniffing protections. Q: What is the charset parameter on text types? A: Text media types often carry a charset parameter, such as text/html; charset=utf-8, that declares the character encoding. Modern web content should almost always use utf-8 so that non-ASCII characters render correctly. Q: Are vendor and structured-suffix types covered? A: Yes. The list includes common structured suffixes like application/ld+json and vendor types such as application/vnd.ms-excel, which use the +suffix and vnd. conventions defined by the media-type registration rules. Q: Is my search sent anywhere? A: No. The entire media-type list ships with the page and all searching happens in your browser. Nothing is uploaded. #### Mobile Phone Penetration by Country Reference URL: https://geratools.com/mobile-penetration-reference Reference table of mobile subscription rates — active SIM cards per 100 inhabitants — and total subscriptions for major countries, with region. Filter by country or region and sort by penetration or total. How to use: 1. Sort by penetration or total: Switch between SIMs per 100 people and total subscriptions to rank countries by density or by raw scale. 2. Filter by country or region: Type a country or region such as Asia or Africa to focus the table. 3. Spot the over-100 markets: Note which countries exceed 100 SIMs per 100 people — a sign of widespread dual-SIM and multi-device use. FAQ: Q: How can a country have more than 100 SIMs per 100 people? A: The figure counts active SIM cards, not unique people. Many users carry two SIMs for separate work and personal numbers or to exploit different network deals, and additional SIMs power tablets, hotspots and IoT devices. So the count often exceeds the population, sometimes well above 100 per 100 inhabitants. Q: What does SIMs per 100 people measure? A: It is the number of active mobile-cellular subscriptions divided by the population, scaled to 100. A value of 120 means 120 active SIMs for every 100 residents. It measures subscription density, not the share of people who own a phone, which is always lower. Q: Does high SIM penetration mean everyone has a phone? A: Not necessarily. Because some people hold several SIMs while others hold none, a country above 100 per 100 can still leave a minority without any mobile service. Unique mobile ownership is a separate, lower statistic than SIM penetration. Q: Which regions lead in mobile penetration? A: Parts of East Asia, the Gulf states and Eastern Europe show very high SIM density, often well over 150 per 100 people, driven by dual-SIM culture and prepaid markets. Some lower-income countries remain below 100 as networks and affordability catch up. Q: Are these figures exact? A: No. Subscription counts come from operator reporting and definitions of an active SIM vary, with inactive accounts sometimes lingering. The figures here are approximate ITU/GSMA-style estimates for a recent year, intended for comparison. #### Mohs Hardness Scale Reference URL: https://geratools.com/mohs-hardness-reference The complete Mohs hardness scale from talc to diamond, with the reference mineral at each level, approximate absolute (Vickers) hardness, and everyday objects you can use to test scratch hardness. Look up any mineral or compare two materials. Runs in your browser. How to use: 1. Browse the scale: View all ten Mohs levels with the defining mineral, a real-world scratch tool, and the approximate absolute hardness for each. 2. Compare two materials: Pick two minerals or test objects to see which scratches which, based on their Mohs values. 3. Use the test objects: Use the listed everyday tools — a fingernail, copper coin, steel knife, glass — to bracket an unknown mineral's hardness. FAQ: Q: What is the Mohs hardness scale? A: The Mohs scale, created by Friedrich Mohs in 1812, ranks minerals 1 to 10 by scratch resistance. A mineral can scratch any with a lower or equal number and is scratched by any higher. It is ordinal, not linear, so the gaps between numbers are not equal. Q: Is the Mohs scale linear? A: No. It is a relative ranking, not a measurement of absolute hardness. Diamond at 10 is far more than ten times harder than talc at 1 — its absolute (Vickers) hardness is roughly 1500 times greater. The jump from corundum (9) to diamond (10) is the largest on the scale. Q: How do I test hardness without lab equipment? A: Use common objects of known hardness as references. A fingernail is about 2.5, a copper coin about 3.5, a steel knife or nail about 5.5, and glass about 5.5 to 6. If your fingernail scratches the mineral it is below 2.5; if a knife does not, the mineral is above 5.5. Q: Which gemstones are hardest? A: Diamond tops the scale at 10, followed by corundum (ruby and sapphire) at 9, and topaz at 8. Hardness matters for jewellery durability — softer stones like opal (about 5.5 to 6.5) and pearl scratch easily and need gentler care. Q: What is the difference between Mohs and Vickers hardness? A: Mohs is an ordinal scratch scale from 1 to 10, while Vickers is an absolute measurement of indentation hardness in kgf/mm². The approximate Vickers figures in this table show how non-linear Mohs really is — each step up represents a steeply increasing absolute hardness. #### Morse Code Reference Chart URL: https://geratools.com/morse-code-reference Translate text to and from International Morse code and browse the full ITU chart of dots and dashes for every letter, digit, and punctuation mark, with instant search and copy. How to use: 1. Choose a direction: Select Text to Morse or Morse to Text in the mode dropdown. 2. Enter your input: Type plain text, or type Morse with spaces between letters and a slash between words. 3. Copy the result: The output updates instantly; use the copy button to grab it. FAQ: Q: How do I write Morse with spaces? A: Separate the dots and dashes of each letter with a single space, and separate words with a forward slash. For example .... . .-.. .-.. --- spells HELLO and a slash starts a new word. Q: What is the timing of dots and dashes? A: A dot is one unit long and a dash is three units. The gap between symbols in a letter is one unit, between letters three units, and between words seven units. This tool shows the pattern, not the audio timing. Q: Is this International or American Morse? A: This chart uses International (ITU) Morse code, the global standard for radio and maritime use. American (Railroad) Morse, an older variant, differs for several letters and is not used here. Q: Why does SOS not have spaces in the famous signal? A: As a distress prosign, SOS is sent as one continuous string ...---... with no inter-letter gaps. Spelled as three separate letters it is ... --- ... This tool encodes it letter by letter. Q: Which punctuation is supported? A: The chart includes the common ITU punctuation marks: period, comma, question mark, apostrophe, slash, brackets, colon, semicolon, equals, plus, minus, and the at sign, among others. #### World Mountains Height Reference URL: https://geratools.com/mountain-height-reference Searchable reference of the world's highest peaks with elevation in metres and feet, the mountain range, the country, and the year of first ascent, so you can compare the tallest mountains on Earth. How to use: 1. Search a peak or range: Type a mountain name, range, or country to filter the ranked list. 2. Read the elevation: See the height in both metres and feet plus the global rank. 3. Check the first ascent: Note the year each summit was first climbed where it is recorded. FAQ: Q: Is Everest the tallest mountain in the world? A: Everest is the highest mountain measured by elevation above sea level, at 8,849 metres. Measured from base to peak Mauna Kea is taller, and measured from Earth's centre Chimborazo's summit is farthest out, but by sea-level height Everest leads. Q: What are the eight-thousanders? A: The eight-thousanders are the 14 mountains that rise above 8,000 metres above sea level, all in the Himalaya and Karakoram ranges of Asia. Climbing all 14 is one of mountaineering's greatest challenges. Q: Why are the heights in metres and feet? A: Mountaineering uses metres internationally, but many English-language sources and older records quote feet. Showing both lets you match whichever figure a guidebook, map, or expedition account uses. Q: How accurate are mountain elevations? A: Modern elevations come from satellite and GPS surveys and are revised occasionally as techniques improve. Everest's official height was updated in 2020. The figures here use the most widely accepted recent measurements. Q: Which range has the most high peaks? A: The Himalaya contains the majority of the world's highest summits, including Everest, while the neighbouring Karakoram holds K2, the second highest. Together these Asian ranges dominate the top of any elevation list. #### Musical Note Frequency Reference URL: https://geratools.com/musical-note-frequency-reference Searchable reference of equal-temperament note frequencies from C0 through B8 with A4 = 440 Hz standard tuning, MIDI numbers, and a re-anchorable reference pitch for 432 Hz or 442 Hz. How to use: 1. Set the reference pitch: Leave A4 at the 440 Hz standard or change it to 432 or 442 Hz to recompute every note for an alternate tuning. 2. Search a note: Type a note like A4 or F#3, or a MIDI number such as 60, to jump straight to it. 3. Read the frequency: Each row shows the note name, its frequency in hertz to two decimals, and its MIDI number. FAQ: Q: How are note frequencies calculated? A: Equal temperament uses the formula f = 440 × 2^((n − 69) / 12), where n is the MIDI note number and 69 is A4. Each semitone multiplies the frequency by the twelfth root of two, roughly 1.0595, so twelve semitones double the pitch exactly one octave higher. Q: What is A4 = 440 Hz? A: A4 is the A above middle C, the standard concert-pitch reference adopted by ISO 16. Fixing it at 440 Hz defines the frequency of every other note in equal temperament. Some orchestras tune to 442 or 443 Hz, and 432 Hz is a popular alternative tuning. Q: What is a MIDI note number? A: MIDI numbers map each piano key to an integer: middle C (C4) is 60 and A4 is 69. They give a compact, octave-aware way to identify pitches in software and hardware, and they feed directly into the frequency formula. Q: Why is middle C4 not exactly 256 Hz? A: 256 Hz for middle C comes from a scientific-pitch convention where each C is a power of two. Standard concert tuning anchors A4 at 440 Hz instead, which makes C4 about 261.63 Hz. The two systems simply use different reference points. Q: Does this work for 432 Hz tuning? A: Yes. Change the A4 reference pitch to 432 and every note rescales by the ratio 432/440. The relative intervals stay identical because equal temperament is defined by ratios, not absolute frequencies. #### NATO STANAG Reference URL: https://geratools.com/nato-stanag-reference Searchable reference of commonly cited NATO STANAGs (Standardization Agreements) with the agreement number, title and subject area — covering ammunition, rank codes, symbology, armour protection levels, language proficiency and more. How to use: 1. Search a STANAG: Type a STANAG number, a keyword from the title, or a subject like ammunition or language to filter the list. 2. Read the subject: Each entry summarises what the agreement standardises so you can confirm you have the right reference. 3. Cite the current edition: Use the number to look up the live edition on official NATO sources, as STANAGs are revised over time. FAQ: Q: What is a STANAG? A: A STANAG is a NATO Standardization Agreement — a document that records member nations' agreement to use common procedures, equipment, terminology or data formats so allied forces can operate together. Many implement an allied publication such as APP-6 for symbology. Q: Why are STANAG numbers cited so often? A: Because they give a precise, language-neutral reference to a specific interoperability standard. Saying STANAG 4569 is unambiguous about which armour protection scheme is meant, across every NATO nation and supplier. Q: What does STANAG 4569 cover? A: STANAG 4569 defines protection levels (Levels 1 to 6) for the occupants of logistic and light armoured vehicles against ballistic, blast and mine threats. Vehicle armour is frequently specified by its STANAG 4569 level. Q: What is STANAG 6001? A: STANAG 6001 defines the Standardized Language Profile, a scale from 0 to 5 rating proficiency in listening, speaking, reading and writing. NATO language requirements and many military and defence jobs quote an SLP such as 3-3-3-3. Q: Does this tool connect to the internet? A: No. The STANAG table is bundled with the page and all searching runs in your browser. Nothing is uploaded, logged or stored. #### NFPA 704 Diamond Reference URL: https://geratools.com/nfpa-704-diamond-reference Decode an NFPA 704 fire diamond: choose the blue health, red flammability and yellow instability ratings 0–4 plus the white special codes to read what each level means for first responders. How to use: 1. Set the three coloured ratings: Pick a 0–4 value for the blue (health), red (flammability) and yellow (instability) quadrants. 2. Add any special codes: Select the white-quadrant symbols such as OX, W or SA if they apply to the substance. 3. Read the decoded meaning: The page prints the plain-English meaning of each rating and special code you choose. FAQ: Q: What do the four quadrants of the NFPA 704 diamond mean? A: Blue (left) is health hazard, red (top) is flammability, yellow (right) is instability/reactivity, and white (bottom) is special hazards. The three coloured quadrants use a 0–4 scale; white holds letter or symbol codes such as OX or W. Q: What does a 4 mean on the scale? A: 4 is the most severe level in each colour. Health 4 means very short exposure can cause death; flammability 4 means it vaporises and burns readily at normal temperatures; instability 4 means it can detonate or explosively react at normal conditions. Q: What do the white special-hazard codes mean? A: Common codes are OX (oxidiser), W with a strikethrough (reacts dangerously with water), and SA (simple asphyxiant gas, used only for nitrogen, helium, neon, argon, krypton and xenon). Some jurisdictions also use unofficial codes like COR or ACID. Q: How is NFPA 704 different from the GHS or UN systems? A: NFPA 704 is a US fixed-installation placard for emergency responders, rating acute hazards under fire conditions. GHS labels are for handling and supply, and UN classes are for transport. The three describe the same chemicals from different angles and are not interchangeable. Q: Does this tool run offline? A: Yes. The full NFPA 704 rating descriptions are built into the page and decoding happens entirely in your browser. Nothing is uploaded or stored. #### nginx Built-in Variables Reference URL: https://geratools.com/nginx-variables-reference Searchable nginx built-in variable reference covering core HTTP, proxy, upstream, SSL and GeoIP variables, including the dynamic $http_, $arg_, $cookie_ and $sent_http_ name patterns. How to use: 1. Filter by module: Narrow the list to core, http_core, proxy, upstream, ssl or geo/realip variables. 2. Search a variable: Type a name such as remote_addr, upstream or ssl_cipher to find it and its meaning. 3. Use it in config: Reference the variable in log_format, proxy_set_header or map and if blocks. FAQ: Q: What is the difference between $uri and $request_uri? A: $request_uri is the full original request URI including the query string and exactly as the client sent it. $uri is the current normalised URI without the query string, and it can change during internal redirects and rewrites, so the two often differ after a rewrite. Q: How do I read an arbitrary request header? A: Use the $http_ prefix followed by the header name lowercased with hyphens turned into underscores. For example the User-Agent header is available as $http_user_agent and X-Forwarded-For as $http_x_forwarded_for. Q: Which variables are most useful in log_format? A: Common choices are $remote_addr, $request, $status, $body_bytes_sent, $http_referer, $http_user_agent, $request_time and the upstream timing variables like $upstream_response_time, which together give a full picture of each request. Q: What does $proxy_add_x_forwarded_for do? A: It returns the incoming X-Forwarded-For header with the current $remote_addr appended. Setting proxy_set_header X-Forwarded-For with this variable correctly chains the client IP when nginx sits behind or in front of other proxies. Q: Are the $upstream_ variables available before the upstream responds? A: They are populated as the upstream interaction progresses, so they are most reliable in log_format after the response completes. Variables like $upstream_addr, $upstream_status and $upstream_response_time reflect the server that handled the request. #### Large Number Names Reference URL: https://geratools.com/number-names-reference Reference table of large number names from million to centillion, showing the power of ten and the differing values in the short-scale and long-scale naming systems. How to use: 1. Browse the names: Scan the table of large-number names with the power of ten they represent in each scale. 2. Compare the two scales: Read across to see how the short scale (used in English-speaking countries) and long scale (used in much of Europe) assign different values to the same name. 3. Look up a value: Search by name or power of ten to find how many zeros a number has and what it is called. FAQ: Q: What is the difference between short scale and long scale? A: In the short scale, each new name is a thousand times the previous one, so a billion is 10^9. In the long scale, each new name is a million times the previous one, so a billion (milliard) is 10^9 but a long-scale billion is 10^12. English uses the short scale; much of continental Europe uses the long scale. Q: How many zeros does a trillion have? A: In the short scale a trillion is 10^12, written with 12 zeros (1,000,000,000,000). In the long scale a trillion is 10^18. The table shows both so you can avoid the common mismatch. Q: What is a googol? A: A googol is 10^100 — a 1 followed by 100 zeros. It is not part of the standard naming series but is included for reference, as is the googolplex (10 to the power of a googol). Q: Why do countries disagree on billion? A: Historically France and Britain used the long scale, while the United States used the short scale. The UK officially switched to the short scale in 1974, so English now uses 10^9 for a billion almost everywhere, but many European languages keep the long scale. Q: Is this data sent anywhere? A: No. The table and search run entirely in your browser. Nothing is uploaded, logged or stored. #### Nut & Spanner Size Reference URL: https://geratools.com/nut-bolt-spanner-size-reference Reference table mapping metric and SAE bolt and nut sizes to the across-flats wrench or spanner size, with thread diameter and the nearest metric/imperial cross-equivalent. How to use: 1. Find your bolt size: Identify the bolt thread (e.g. M10 metric or 3/8 inch) or measure the nut across its flats. 2. Read the spanner size: The table gives the across-flats spanner or socket size for each standard nut and bolt head. 3. Use the cross-equivalent: When you only have the other system's tools, use the nearest metric or imperial spanner shown — noting any small clearance difference. FAQ: Q: What does across-flats mean? A: Across-flats (AF) is the distance between two opposite flat faces of a hexagonal nut or bolt head — the dimension a spanner or socket grips. It is the same as the spanner's nominal size. For example, a standard M10 bolt has a 17 mm across-flats head, so it needs a 17 mm spanner. Q: Why doesn't the bolt diameter match the spanner size? A: The thread diameter (M10 = 10 mm shank) is much smaller than the hex head it drives. The head is sized for grip and torque, so an M10 takes a 17 mm spanner, an M12 a 19 mm, and so on. Always size the spanner to the head, never the thread. Q: Can I use a metric spanner on an imperial bolt? A: Sometimes, with care. Some sizes are very close — a 13 mm spanner nearly fits a 1/2-inch AF head (12.7 mm) but is slightly loose and can round corners. Use the correctly matched system whenever possible; the cross-equivalents here are emergency substitutes, not exact fits. Q: What is the difference between coarse and fine thread for spanner size? A: The spanner size depends only on the hex head's across-flats dimension, not the thread pitch. An M10 coarse and M10 fine bolt share the same 17 mm head, so the same spanner fits both. Thread pitch only matters for the matching nut, not the wrench. Q: Is this reference processed online? A: No. All size data and the lookup run locally in your browser. Nothing is uploaded. #### OAuth 2.0 Grant Types Reference URL: https://geratools.com/oauth-grant-types Reference for OAuth 2.0 grant types — authorization code, PKCE, client credentials, refresh token, device, implicit and password — each with its step-by-step flow, spec and security guidance under OAuth 2.1. How to use: 1. Search grants: Type a grant name or keyword such as PKCE, device or client_credentials to filter. 2. Filter by status: Show only OAuth 2.1 recommended grants or the deprecated implicit and password flows. 3. Expand the flow: Click a grant to read its step-by-step flow and the key security notes for it. FAQ: Q: Which OAuth grant type should I use? A: For apps that redirect a user, use Authorization Code with PKCE — it now suits both confidential and public clients. For machine-to-machine calls use Client Credentials, and for input-constrained devices like TVs use the Device Authorization grant. Use Refresh Token to renew access without re-prompting. Q: Why is the Implicit grant deprecated? A: Implicit returned the access token directly in the redirect URL fragment, where it can leak through browser history, referrers and logs, and it offered no client authentication. OAuth 2.1 and the Security BCP remove it in favour of Authorization Code with PKCE. Q: What problem does PKCE solve? A: PKCE (Proof Key for Code Exchange) binds the authorization code to a one-time secret the client generates. Even if an attacker intercepts the code on the redirect, they cannot exchange it without the original code_verifier, which defeats authorization-code interception on public clients. Q: Does Client Credentials involve a user? A: No. The client authenticates as itself to access its own resources, with no end-user and usually no refresh token. It is the right choice for backend services and cron jobs, but never for acting on behalf of a specific user. Q: Should I still use the Password grant? A: Avoid it. The Resource Owner Password Credentials grant hands the user's password to the client, which breaks SSO, MFA and consent. OAuth 2.1 removes it; it survives only for migrating legacy first-party apps and should be retired. #### Ocean & Sea Depth Reference URL: https://geratools.com/ocean-depth-reference Reference table of the five oceans and 20+ major seas with average depth, maximum depth in metres, and the deepest sounded point of each. Filter by name or trench and sort by depth. How to use: 1. Choose oceans, seas or both: Use the type selector to show only the five oceans, only the major seas, or every water body together. 2. Filter by name or feature: Type an ocean, sea or trench name to narrow the list to matching water bodies. 3. Compare average against maximum: Read the average depth for typical conditions and the maximum depth for the single deepest sounded point. FAQ: Q: What is the deepest point in the ocean? A: The Challenger Deep in the Mariana Trench of the Pacific Ocean is the deepest known point, at about 10,935 m below sea level. That is deeper than Mount Everest is tall, so Everest could sit at the bottom and still be fully submerged. Q: What is the difference between average and maximum depth? A: Average depth is the total water volume divided by surface area, representing the typical depth across the whole basin. Maximum depth is the single deepest sounded point, usually in a trench. The two can differ by thousands of metres. Q: Why is the Arctic Ocean so much shallower? A: The Arctic Ocean sits largely over continental shelf and has an average depth of only about 1,205 m, far less than the Pacific's 4,280 m. Broad shallow shelves around its margins pull the average down sharply. Q: Which sea is the deepest? A: The Philippine Sea is the deepest marginal sea, reaching about 10,540 m in the Philippine Trench. Several Pacific and Southern Ocean seas exceed 6,000 m, while shelf seas like the Baltic and Yellow Sea stay under 500 m. Q: Are the depth figures exact? A: No. Deep-ocean soundings are refined as survey technology improves, and the exact figure for points like the Challenger Deep varies by a few metres between sources. The values here are widely cited approximations for reference. #### OpenID Connect Claims Reference URL: https://geratools.com/openid-connect-claims Searchable OpenID Connect claim reference covering ID token protocol claims and the profile, email, phone and address scopes, with each claim's data type, releasing scope and example value. How to use: 1. Search claims: Type a claim name or word such as sub, email, name or address to filter the list. 2. Filter by location: Choose whether to see claims from the ID Token, the UserInfo endpoint, or both. 3. Read type and scope: Each claim shows its JSON type, the scope that releases it and an example value. FAQ: Q: What is an OpenID Connect claim? A: A claim is a single piece of information asserted about the authenticated user or the token itself, such as sub (the user identifier), email or name. Claims are delivered as JSON members inside the ID token and from the UserInfo endpoint. Q: Which claim should I use as the user's unique key? A: Always use sub (subject). It is locally unique to the issuer and never reassigned. Do not key off email or preferred_username — those can change or be reused, which leads to account-takeover bugs. Q: How do scopes relate to claims? A: Scopes group claims for consent. Requesting the profile scope releases name, given_name, picture and similar; email releases email and email_verified; phone releases phone_number and its verified flag; and address releases the structured address object. The openid scope is mandatory and yields sub. Q: What does email_verified mean? A: It is a boolean asserting that the provider verified the user controls that email address at some point. Treat a missing or false value as unverified, and never grant trust based on the email alone without checking this flag. Q: Should I read claims from the ID token or UserInfo? A: The ID token carries authentication claims (iss, sub, aud, exp, nonce) and may include profile claims. The UserInfo endpoint returns the same profile claims fresh on request. Use the ID token for the session, and call UserInfo when you need current profile data not present in the token. #### OpenSSL Commands Cheatsheet URL: https://geratools.com/openssl-commands-cheatsheet OpenSSL CLI cheatsheet covering req, x509, s_client, genrsa/genpkey, rsa, pkcs12, dgst and enc subcommands — each with a ready-to-run example for generating keys, CSRs, certificates and testing TLS endpoints. How to use: 1. Search the commands: Type a subcommand or keyword such as "csr", "s_client" or "fingerprint" to filter the openssl cheatsheet. 2. Copy the example: Use the copy button on any entry to grab the full command, then fill in your own file names and domains. 3. Run and verify: Run the command locally; many entries pair a generate step with a verify step so you can confirm the output. FAQ: Q: How do I generate a private key and CSR with openssl? A: Generate a key with openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:2048 -out key.pem, then create a CSR with openssl req -new -key key.pem -out req.csr and answer the prompts (or pass -subj to fill them inline). Send the CSR to your certificate authority; keep key.pem secret. Q: How do I inspect a certificate with openssl? A: Use openssl x509 -in cert.pem -noout -text to print the full human-readable certificate including subject, issuer, validity dates and SAN entries. Add -fingerprint -sha256 for the fingerprint, or -dates to see only notBefore and notAfter. Q: How do I test a TLS server from the command line? A: openssl s_client -connect example.com:443 -servername example.com opens a TLS connection and prints the certificate chain, negotiated protocol and cipher. The -servername (SNI) flag is important on shared hosts. Pipe in echo or add -quiet to avoid hanging on input. Q: What is the difference between genrsa and genpkey? A: genrsa is the older, RSA-specific key generator. genpkey is the modern, algorithm-agnostic command that can produce RSA, EC (elliptic curve), Ed25519 and other keys with consistent options. Prefer genpkey for new work; genrsa still appears widely in older guides. Q: How do I convert a certificate to PKCS#12? A: Bundle a certificate and its private key into a .p12/.pfx file (used by Windows, Java and many servers) with openssl pkcs12 -export -in cert.pem -inkey key.pem -out bundle.p12. You will be asked to set an export password. Use openssl pkcs12 -in bundle.p12 to read it back. #### Pallet Size Reference URL: https://geratools.com/pallet-size-reference Reference table of standard pallet types — EUR/EPAL, ISO, US GMA and others — with footprint in mm and inches, material, static and dynamic load ratings, plus a unit toggle. How to use: 1. Find your pallet standard: Locate the EUR, ISO or US GMA pallet that matches your region and supply chain. 2. Read the load ratings: Check static (stacked at rest) and dynamic (in motion on a forklift) load limits against your cargo weight. 3. Toggle mm or inches: Switch units to match European millimetre specs or US inch specs on your shipping paperwork. FAQ: Q: What is a EUR pallet? A: A EUR or EPAL pallet measures 1200 × 800 mm and is the dominant pallet across Europe. Genuine EPAL pallets carry a branded stamp and are part of an exchange pool, so they can be swapped one-for-one rather than discarded after each shipment. Q: What is a GMA pallet? A: The GMA (Grocery Manufacturers Association) pallet is the US standard at 48 × 40 inches (1219 × 1016 mm). It is the most common pallet in North America and is sized to fit two-wide in a standard 40ft container and on most US truck trailers. Q: What is the difference between static and dynamic load? A: Dynamic load is the maximum weight a pallet can safely carry while being moved on a forklift or pallet jack. Static load is the larger weight it can bear when stationary, such as in a stacked rack. Always size cargo against the lower dynamic rating for transit. Q: Which pallet fits a shipping container best? A: EUR pallets (1200 × 800 mm) load 11 per tier in a 20ft and ~25 in a 40ft container. US GMA pallets (1219 × 1016 mm) fit 10 per tier in a 20ft. Picking the pallet that tiles the container floor reduces wasted cube and shipping cost. Q: Is this reference processed online? A: No. All pallet data and the unit conversion run in your browser. Nothing is uploaded. #### ISO Paper Sizes Reference URL: https://geratools.com/paper-sizes-iso Full ISO 216 A-series and B-series paper size table with width and height in millimetres, centimetres, and inches. Switch series and units instantly, from A0 down to A10 and B0 to B10. How to use: 1. Choose A or B series: Pick the A series for everyday office and print sizes or the B series for posters, books, and envelopes. 2. Select your units: Switch between millimetres, centimetres, and inches depending on what your software or printer expects. 3. Read the dimensions: Find your paper size in the table and read its width, height, and combined dimensions. FAQ: Q: What are the dimensions of A4 paper? A: A4 measures 210 by 297 millimetres, which is 21.0 by 29.7 centimetres or about 8.27 by 11.69 inches. It is the standard office and letter-equivalent size across most of the world outside North America. Q: Why is the aspect ratio of ISO paper one to the square root of two? A: The ratio of 1 to 1.414 is special because halving the long side keeps the same proportions. That means cutting or folding any A size in half produces two sheets of the next smaller A size with identical shape, which makes scaling between sizes lossless. Q: How big is A0 paper? A: A0 measures 841 by 1189 millimetres and has an area of almost exactly one square metre. Every smaller A size is defined by repeatedly halving the long dimension, so A1 is half of A0, A2 is half of A1, and so on. Q: What is the difference between the A and B series? A: Both share the 1 to root-two ratio, but B sizes sit between consecutive A sizes. B0 is one metre wide and is larger than A0, so the B series is used for posters, books, passports, and envelopes that need to hold an A size with margin. Q: Why do the dimensions not always halve to a whole number? A: ISO 216 defines each size by halving the previous one and then rounding down to the nearest whole millimetre. That rounding is why A5 is 148 by 210 rather than exactly 148.5, and the table reproduces the official rounded values. #### PCIe Generation Reference URL: https://geratools.com/pcie-generation-reference Reference table for PCI Express generations 1.0 to 7.0 — transfer rate in GT/s, line encoding, per-lane bandwidth, and total throughput across x1/x4/x8/x16 widths, with a built-in bandwidth calculator. How to use: 1. Filter generations: Type a generation like 4.0 or 5.0, or an encoding like PAM4, to narrow the reference table. 2. Pick gen and width: Use the calculator to select a PCIe generation and lane width (x1, x4, x8, x16). 3. Read the bandwidth: The result shows per-direction and bidirectional bandwidth in GB/s for your chosen link. FAQ: Q: How much bandwidth does PCIe 4.0 x4 provide? A: PCIe 4.0 delivers about 1.97 GB/s per lane after encoding, so an x4 link provides roughly 7.88 GB/s in each direction. That is the typical bandwidth available to a Gen4 NVMe SSD. Q: What is the difference between GT/s and GB/s? A: GT/s (gigatransfers per second) is the raw signalling rate per lane. GB/s is usable data after subtracting line-encoding overhead. PCIe 3.0 runs at 8 GT/s but yields about 0.985 GB/s per lane due to 128b/130b encoding. Q: Why does each PCIe generation double in speed? A: Generations 1 through 5 roughly double the per-lane transfer rate each time by increasing the signalling frequency. Generations 6 and 7 instead use PAM4 four-level signalling, which carries two bits per symbol, doubling throughput without doubling the clock. Q: Are PCIe generations backward compatible? A: Yes. PCIe is forward and backward compatible. A newer card works in an older slot and vice versa, but the link negotiates down to the slower of the two generations and the narrower lane width. Q: What changed with PCIe 6.0 encoding? A: PCIe 6.0 moved from NRZ to PAM4 signalling and adopted FLIT-based framing with forward error correction (FEC). This keeps the bit error rate manageable at the higher symbol density while doubling the effective data rate. #### pH Scale Reference Table URL: https://geratools.com/ph-scale-reference Reference table of approximate pH values for 28 everyday acids and bases, with a built-in pH ↔ pOH ↔ hydrogen-ion concentration calculator and a substance filter. How to use: 1. Enter a pH value: Type any pH from 0 to 14 to see whether it is acidic, neutral or basic and its derived pOH and ion concentrations. 2. Read the substance table: Scan the list of common substances sorted from most acidic to most basic to compare everyday materials. 3. Filter by name: Type a substance name such as coffee or bleach to jump straight to its approximate pH value. FAQ: Q: What does the pH scale measure? A: pH measures the acidity or alkalinity of a water-based solution on a scale of 0 to 14. It is defined as the negative base-10 logarithm of the hydrogen-ion concentration, pH = -log10[H+]. Lower values are more acidic, higher values more basic. Q: Why is pH 7 neutral? A: At 25 degrees Celsius pure water self-ionises so that hydrogen and hydroxide ions are equal at 1e-7 mol/L each, giving pH 7. The neutral point shifts slightly with temperature, so very hot water can have a neutral pH below 7. Q: How much stronger is one pH unit? A: The scale is logarithmic, so each whole unit represents a tenfold change in hydrogen-ion concentration. A solution at pH 3 has ten times more hydrogen ions than pH 4 and one hundred times more than pH 5. Q: How is pOH related to pH? A: In water at 25 degrees Celsius pH and pOH always add up to 14, because the product of the hydrogen-ion and hydroxide-ion concentrations is fixed at 1e-14. So pOH = 14 minus pH. Q: Are the listed pH values exact? A: No. They are typical approximate values. Real pH varies with temperature, concentration, dissolved gases and the specific sample, so treat the table as a guide rather than a precise measurement. #### IPA Phonetic Symbol Reference URL: https://geratools.com/phonetic-transcription-reference Searchable reference of International Phonetic Alphabet symbols used to transcribe English — vowels, diphthongs, consonants, and stress marks — each with a sound type, an example word, and its Unicode code point. Click any symbol to copy it. How to use: 1. Search a sound: Type a symbol, a sound category such as vowel or fricative, or an example word to filter the chart. 2. Read the row: Each row gives the IPA symbol, its phonetic description, an English example word, and the Unicode code point. 3. Copy the symbol: Click any symbol button to copy the exact IPA character to your clipboard for use in documents or code. FAQ: Q: What is the IPA? A: The International Phonetic Alphabet is a standardised set of symbols, one per distinct speech sound, maintained by the International Phonetic Association. It lets linguists, dictionaries, and language learners write pronunciation unambiguously across any language. Q: Why does each symbol have a Unicode code point? A: Many IPA symbols are not on a normal keyboard, so they are encoded as specific Unicode characters. Knowing the code point lets you insert the exact glyph in HTML, JSON, or a programming string without copy-paste errors. Q: Which accent does this chart describe? A: The vowel set here follows Received Pronunciation, the reference accent used in many British dictionaries. Consonant symbols are largely shared across English accents, though General American differs on some vowels. Q: What is the schwa? A: The schwa, written as the symbol at code point U+0259, is the neutral mid-central vowel heard in unstressed syllables such as the first sound of about. It is the most common vowel sound in English. Q: What do the small vertical marks mean? A: The raised vertical line is the primary stress mark placed before the stressed syllable, and the lowered line marks secondary stress. The colon-like length mark shows that a vowel is held longer. #### Physical Constants Reference URL: https://geratools.com/physical-constants-reference Look up CODATA 2018 values for 30+ fundamental physical constants including the speed of light, Planck constant, Avogadro number, gravitational constant, and Boltzmann constant, with units and exact-value flags. Runs in your browser. How to use: 1. Search the list: Type a constant name, symbol, or unit to filter the table of fundamental constants. 2. Read the value and unit: Each row shows the CODATA value, its SI unit, and whether the value is exact or measured. 3. Note exact versus measured: Constants flagged exact have no uncertainty since the 2019 SI redefinition fixed them by definition. FAQ: Q: What is CODATA? A: CODATA is the Committee on Data for Science and Technology, which periodically publishes internationally recommended values of the fundamental physical constants. The values here follow the CODATA 2018 adjustment, the basis of the 2019 SI redefinition. Q: Which constants are exact? A: Constants like the speed of light, Planck constant, elementary charge, Boltzmann constant, and Avogadro number are now exact by definition, with zero uncertainty. They were fixed to defined values when the SI was redefined in 2019, which in turn defines the base units. Q: Why does the gravitational constant have more uncertainty? A: Big G is notoriously hard to measure because gravity is extremely weak and cannot be shielded. It is known to only about four significant figures, far less precisely than electromagnetic or atomic constants, and its value is still actively refined. Q: What is the fine-structure constant? A: The fine-structure constant, about 1/137, is a dimensionless number that sets the strength of the electromagnetic interaction. Because it has no units, it is the same in every system of measurement and is considered one of the most fundamental numbers in physics. Q: Are these values reliable for calculations? A: Yes. These are the internationally accepted reference values used in physics and engineering. For the highest-precision work consult the latest CODATA release directly, since measured constants are refined as experimental techniques improve. #### Pipe Size Reference (NPS / DN) URL: https://geratools.com/pipe-size-reference Reference table mapping NPS (imperial) and DN (metric) nominal pipe sizes to their true outside diameter, plus wall thickness and inside diameter for schedules 40, 80, and 160. How to use: 1. Select a nominal size: Pick the NPS / DN size you are working with — the dropdown lists each nominal size with its true outside diameter. 2. Choose a schedule: Select schedule 40, 80, or 160 to see the corresponding wall thickness for that pipe weight. 3. Read the real dimensions: The tool shows the actual outside diameter, the wall thickness, and the resulting inside diameter in both millimetres and inches. FAQ: Q: Why does a 2 inch pipe not measure 2 inches? A: NPS is a nominal label, not a measurement. For sizes up to 12 inch the actual outside diameter is larger than the nominal number — a 2 inch NPS pipe has a 60.3 mm (2.375 in) outside diameter. From 14 inch up, NPS equals the actual OD. Q: What does the schedule number mean? A: Schedule sets the wall thickness for a given outside diameter. A higher schedule (80, 160) means a thicker wall and a smaller bore for the same OD, suited to higher pressures. Schedule 40 is the common standard weight. Q: How is inside diameter calculated? A: Inside diameter equals the outside diameter minus twice the wall thickness, because the wall surrounds the bore on both sides. A 60.3 mm OD pipe with a 3.91 mm wall has a bore of 60.3 minus 7.82, about 52.5 mm. Q: Is NPS the same as DN? A: They label the same physical pipes but in different units. DN (diameter nominal) is the rounded metric equivalent of NPS — DN50 corresponds to NPS 2. The outside diameter is identical; only the label changes. Q: Does outside diameter change with schedule? A: No. For a given nominal size the outside diameter is fixed so the same fittings and threads work across schedules. Only the wall thickness, and therefore the inside diameter, changes with the schedule. #### POSIX Regex Reference URL: https://geratools.com/posix-regex-reference Searchable POSIX regular expression reference comparing Basic and Extended syntax. See how grouping, alternation, quantifiers and bracket character classes differ between BRE and ERE, plus which flavor grep, sed and awk use. How to use: 1. Search a construct: Type a feature, syntax fragment or description such as alternation or backreference to filter the comparison tables. 2. Compare BRE and ERE columns: Each row shows the Basic and Extended form side by side so you know when to escape a metacharacter and when not to. 3. Pick the right tool flavor: Check the tool flavors section to know whether grep, sed, awk or find uses BRE or ERE by default and which flag switches it. FAQ: Q: What is the difference between BRE and ERE? A: Basic Regular Expressions (BRE) treat characters like the pipe, plus, question mark, braces and parentheses as literals unless backslash-escaped. Extended Regular Expressions (ERE) treat those same characters as metacharacters directly. BRE is the older POSIX form used by default in grep and sed. Q: Why does grep need escaped parentheses but grep -E does not? A: Plain grep uses BRE, where parentheses are literal characters and grouping requires the escaped form \( \). With grep -E it switches to ERE, where bare parentheses already mean grouping. This is the single most common source of confusion between the two flavors. Q: Can I use \d or \w in POSIX regex? A: No. Shorthand classes like \d, \w and \s are Perl-compatible (PCRE) extensions and are not part of POSIX. The portable equivalents are bracket character classes such as [[:digit:]], [[:alnum:]] and [[:space:]] used inside a bracket expression. Q: Why must a character class be written as [[:digit:]]? A: The token [:digit:] is only meaningful inside a bracket expression. The outer pair of brackets forms the bracket expression and the inner [:digit:] names the class, so a single digit is matched by [[:digit:]]. Writing [:digit:] alone matches the literal characters colon, d, i, g, i and t. Q: Do POSIX EREs support backreferences? A: Strictly, no. POSIX defines backreferences (\1 through \9) only for Basic Regular Expressions. Many ERE engines add them as a non-portable extension, but relying on a backreference in awk or grep -E is not guaranteed by the standard. #### Powers of Two Reference Table URL: https://geratools.com/powers-of-two-reference Reference table of powers of two from 2^0 up to 2^256, showing each value in decimal and hexadecimal with binary-prefix labels (KiB, MiB, GiB). Exact BigInt values you can copy for bit masks, buffer sizes, and limits. How to use: 1. Choose the range: Enter the highest exponent you want listed, from 0 up to 256. 2. Read decimal and hex: Each row shows 2 raised to that exponent in both base 10 and hexadecimal. 3. Copy a value: Use the copy button on any row to grab the exact decimal value for code. FAQ: Q: Why do powers of two matter in computing? A: Computers store data in bits, so capacities, address ranges, and limits cluster on powers of two. A byte holds 2^8 = 256 values and a 32-bit unsigned integer maxes out at 2^32 - 1, which is why these exact numbers come up constantly. Q: What are KiB, MiB, and GiB? A: They are binary prefixes: 1 KiB = 2^10 = 1024 bytes, 1 MiB = 2^20, and 1 GiB = 2^30. They differ from the decimal SI prefixes (kB = 1000 bytes), and this table marks the round powers where each applies. Q: How are the large values kept exact? A: Values are computed with BigInt, so even 2^256 is shown as its full exact integer. Ordinary floating-point numbers lose precision above 2^53, so a naive table would print wrong digits for large exponents. Q: How do I read the hexadecimal column? A: Powers of two are clean in hex: 2^4 is 0x10, 2^8 is 0x100, and each extra factor of 16 (four bits) adds a trailing zero. This makes hex handy for bit masks and memory offsets. Q: What is the largest exponent I can list? A: You can list up to 2^256. That is far beyond any common machine word size but useful for cryptographic key spaces, where 2^128 and 2^256 describe the number of possible keys. #### Prime Numbers Reference Table URL: https://geratools.com/prime-number-reference Searchable reference of all 168 prime numbers from 2 to 997, with each prime's index, plus a built-in primality checker that tests any number you enter. How to use: 1. Browse the primes: Scan the table of all 168 prime numbers from 2 to 997, each shown with its position in the sequence. 2. Check any number: Type a number into the checker to test whether it is prime, with the smallest factor shown if it is composite. 3. Search the table: Filter the prime list by typing a number to jump to nearby primes. FAQ: Q: What is a prime number? A: A prime number is a whole number greater than 1 whose only divisors are 1 and itself. The first few are 2, 3, 5, 7, 11 and 13. Numbers greater than 1 that are not prime are called composite. Q: How many primes are there below 1,000? A: There are exactly 168 prime numbers from 2 to 997. The density of primes thins out as numbers grow, a pattern described by the prime number theorem. Q: Is 1 a prime number? A: No. By definition a prime must have exactly two distinct divisors, 1 and itself. The number 1 has only one divisor, so it is neither prime nor composite. The number 2 is the smallest prime and the only even one. Q: How does the checker decide if a number is prime? A: It uses trial division: it tests divisibility by 2, then by odd numbers up to the square root of the input. If any divides evenly the number is composite and the smallest such factor is shown; otherwise it is prime. Checking up to the square root is enough because a larger factor must pair with a smaller one. Q: Is this data sent anywhere? A: No. The table and the primality check run entirely in your browser. Nothing is uploaded, logged or stored. #### Python List Methods Reference URL: https://geratools.com/python-list-methods Searchable reference for all Python list methods — append, extend, insert, remove, pop, sort, reverse — showing each method's signature, return value, and whether it mutates the list in place. How to use: 1. Search methods: Type a method name or keyword such as add, remove, or sort to filter the list methods. 2. Check the mutation flag: Each entry shows whether the method mutates the list in place (returning None) or returns a new value. 3. Read the signature: See the call signature and a short description, including common gotchas like sort returning None. FAQ: Q: Why does list.sort() return None? A: list.sort() sorts the list in place and deliberately returns None to signal that it mutated the object rather than producing a new one. This is a Python convention for in-place methods. A common bug is writing items = items.sort(), which assigns None; to get a sorted copy use sorted(items), which returns a new list and leaves the original unchanged. Q: What is the difference between append and extend? A: append(x) adds its single argument as one new element at the end, so appending a list nests it. extend(iterable) iterates its argument and adds each element individually, so extending with a list concatenates. lst.append([1,2]) gives [..., [1,2]] while lst.extend([1,2]) gives [..., 1, 2]. Q: What is the difference between remove and pop? A: remove(value) deletes the first element equal to value and returns None, raising ValueError if the value is absent. pop(index=-1) removes the element at the given index, defaulting to the last, and returns that element. Use remove when you know the value, pop when you know the position or want the removed item back. Q: How do I copy a list? A: list.copy() returns a shallow copy — a new list whose elements are the same objects. The same effect comes from list(original) or original[:]. A shallow copy is independent at the top level but shares nested mutable objects, so changing a nested list affects both copies. Use copy.deepcopy for a fully independent clone. Q: Is this the complete list of list methods? A: Yes. Python's list type has a small, fixed set of methods — append, extend, insert, remove, pop, clear, index, count, sort, reverse, and copy — all of which are listed here with their mutation behavior. Built-in functions like len, sorted, and reversed operate on lists but are not list methods; see the Built-in Functions reference for those. #### Python Logging Levels Reference URL: https://geratools.com/python-logging-levels Reference for the Python logging module severity levels — DEBUG, INFO, WARNING, ERROR, CRITICAL — with their numeric values, NOTSET semantics and a live threshold filter showing which records each setLevel emits. How to use: 1. Search the levels: Type a level name, numeric value or use case to filter the table to the matching severities. 2. Set a threshold: Pick a setLevel threshold to see which levels a logger or handler will emit versus suppress. 3. Apply the guidance: Use the per-level use cases and example calls to choose the right severity for each log line. FAQ: Q: What are the numeric values of Python logging levels? A: NOTSET is 0, DEBUG is 10, INFO is 20, WARNING is 30, ERROR is 40 and CRITICAL is 50. They are spaced by 10 so you can insert custom levels in between, such as 15 or 25. Q: What is the default logging level? A: If you never configure the root logger, its effective level is WARNING (30). That means DEBUG and INFO records are silently dropped until you call logging.basicConfig or setLevel with a lower value. Q: What does NOTSET mean? A: NOTSET (0) is a sentinel, not a real severity. A non-root logger set to NOTSET delegates to its parent's effective level. On the root logger, NOTSET is treated as WARNING. Q: How does a record get emitted? A: A record is processed when its numeric level is greater than or equal to the logger's effective level, then again checked against each handler's level. Both gates must pass for output to appear. Q: Can I add my own level? A: Yes. Call logging.addLevelName(value, "NAME") to register a label, and you can log at any integer value with log.log(value, msg). Common conventions are 15 for TRACE and 25 for a NOTICE between INFO and WARNING. #### Radio Frequency Band Reference URL: https://geratools.com/radio-frequency-band-reference A reference of the ITU radio frequency bands from ELF through EHF, with each band's frequency range, wavelength range, and typical applications. Enter any frequency to find which band it falls in and its exact wavelength. Runs in your browser. How to use: 1. Browse the bands: View the nine ITU bands from ELF to EHF, each with its frequency range, corresponding wavelength range, and common uses. 2. Look up a frequency: Enter a frequency and choose Hz, kHz, MHz, or GHz; the tool identifies the band and computes the exact wavelength. 3. Read the application: The matching band is highlighted so you can see what services typically operate in that part of the spectrum. FAQ: Q: How are radio frequency bands defined? A: The ITU divides the radio spectrum into bands by decade of frequency. Each band spans a factor of ten, for example VHF from 30 to 300 MHz and UHF from 300 MHz to 3 GHz. The bands are named by abbreviation, from ELF (extremely low frequency) up to EHF (extremely high frequency). Q: How do I convert frequency to wavelength? A: Wavelength equals the speed of light divided by frequency. The speed of light is about 299,792,458 metres per second. So a 100 MHz FM signal has a wavelength of roughly 3 metres, and a 2.4 GHz Wi-Fi signal about 12.5 centimetres. Q: What is each band used for? A: VLF and LF carry navigation and time signals; MF handles AM radio; HF covers shortwave and amateur radio; VHF runs FM radio and TV; UHF carries mobile phones, Wi-Fi, and GPS; SHF and EHF handle satellite, radar, and 5G millimetre-wave links. Q: Why do lower frequencies travel further? A: Lower-frequency, longer-wavelength signals diffract around obstacles and the curve of the Earth, and HF bands can reflect off the ionosphere for global propagation. Higher frequencies travel in straighter lines, carry more data, but are blocked more easily by terrain, buildings, and rain. Q: What is the relationship between wavelength and antenna size? A: Efficient antennas are sized in proportion to wavelength, often a quarter or half of it. Long-wavelength VLF signals need enormous antennas, while short-wavelength microwave links use small dishes and patch antennas, which is why higher bands suit compact devices. #### Redis Commands Reference URL: https://geratools.com/redis-commands-reference Searchable Redis command reference grouped by data structure — strings, hashes, lists, sets, sorted sets and generic key commands — with syntax, time complexity and the version each was introduced. How to use: 1. Search a command: Type part of a command name or description, such as "ZADD" or "expire", to filter the list. 2. Filter by structure: Choose a data structure like list, set or zset to see only its commands. 3. Read the complexity: Check the time complexity before using a command on large keys, and copy the syntax into redis-cli. FAQ: Q: What does the time complexity column mean? A: It is the Big-O cost of a single call, where N is the number of elements involved. Redis is single-threaded, so an O(N) command on a huge key blocks every other client until it finishes. Q: Why should I avoid KEYS in production? A: KEYS scans the entire keyspace in one blocking O(N) operation, freezing the server on large databases. Use SCAN, which returns a cursor and iterates incrementally without blocking, instead. Q: What is the difference between SET with EX and EXPIRE? A: SET key value EX 60 sets the value and a 60-second TTL atomically in one command. EXPIRE sets a TTL on a key that already exists. Using SET ... EX avoids a race where the key exists briefly without an expiry. Q: How are sorted sets ordered? A: A sorted set (zset) keeps members ordered by an associated floating-point score. ZRANGE returns members by index from lowest to highest score, and ZRANGEBYSCORE returns members within a score window. Q: Are these the only Redis commands? A: No. Redis has hundreds of commands including streams, pub/sub, transactions, scripting and server administration. This reference focuses on the core data-structure commands developers use most. #### Refractive Index Reference URL: https://geratools.com/refractive-index-reference Reference table of refractive indices at 589 nm for 35+ optical materials — glasses, crystals, liquids, and plastics — with a built-in critical-angle calculator for total internal reflection. Runs in your browser. How to use: 1. Search for a material: Type a name such as "glass", "diamond", or "water" to filter the index table instantly. 2. Filter by group: Use the group selector to narrow to gases, liquids, glasses, crystals, or plastics. 3. Find the critical angle: Choose two media to compute the critical angle for total internal reflection when light passes from the denser into the rarer medium. FAQ: Q: What is refractive index? A: Refractive index, n, is the ratio of the speed of light in vacuum to its speed in a material. A value of 1.5 means light travels 1.5 times slower in that medium than in vacuum. Higher n bends light more strongly at a surface, which is why diamond (n = 2.42) sparkles so much. Q: Why is the wavelength 589 nm specified? A: Refractive index depends on wavelength, an effect called dispersion. The values here are quoted at 589 nm, the bright yellow sodium D line, which is the conventional reference for optical glass. At blue wavelengths n is slightly higher, and at red slightly lower. Q: How is the critical angle calculated? A: The critical angle is θc = arcsin(n₂/n₁), valid only when light travels from a denser medium (n₁) into a rarer one (n₂), so n₁ is greater than n₂. Beyond this angle of incidence all the light reflects internally, the principle behind optical fibres and prisms. Q: How does refractive index relate to Snell's law? A: Snell's law, n₁·sin θ₁ = n₂·sin θ₂, governs how light bends at an interface. The larger the index difference, the more the ray bends. Setting θ₂ to 90 degrees gives the critical angle, the steepest incidence that can still escape into the second medium. Q: Does temperature change the refractive index? A: Yes, modestly. As a material warms it usually becomes slightly less dense and its index falls a little; liquids change more than solids. The values here are near 25°C, suitable for general work, but precision optics account for both temperature and wavelength. #### Regex Lookahead/Lookbehind Reference URL: https://geratools.com/regex-lookahead-lookbehind Reference for zero-width regex lookaround assertions — positive and negative lookahead and lookbehind — with the exact syntax per flavor and notes on variable-length lookbehind support. How to use: 1. Pick the assertion: Choose positive or negative, lookahead or lookbehind, based on whether you must match before or after a position. 2. Copy the flavor syntax: Each row gives the exact token for PCRE, JavaScript, Python and .NET so you can paste the right form. 3. Check length support: Read the variable-length lookbehind notes — some engines require fixed-width lookbehind patterns. FAQ: Q: What is a zero-width assertion? A: A zero-width assertion matches a position rather than characters, so it consumes no input. Lookaround assertions test what comes before or after the current position and then the regex engine continues from where it was, never advancing past the asserted text. Q: What is the syntax for negative lookahead? A: Negative lookahead is (?!...). It succeeds at a position only if the enclosed pattern does NOT match starting there. For example q(?!u) matches a q that is not followed by a u. The syntax is identical in PCRE, JavaScript, Python and .NET. Q: Does JavaScript support lookbehind? A: Yes. Lookbehind — (?<=...) and (?...)) and Unicode behaviour and variable-width lookbehind support vary by engine. Always confirm edge cases in your engine. Q: Does this tool process my patterns online? A: No. The reference is a static table filtered in your browser. Nothing you type is uploaded, logged or stored. #### Regex Tokens Cheatsheet URL: https://geratools.com/regex-tokens-cheatsheet A searchable regular-expression token reference covering character classes, anchors, quantifiers, groups and lookaround, with per-flavor support flags for PCRE, JavaScript, Python and .NET, plus a live tester. How to use: 1. Search a token: Type a token like \d or a concept like lookahead or quantifier to filter the reference table. 2. Filter by flavor: Pick PCRE, JavaScript, Python or .NET to see only the tokens that flavor supports. 3. Test a pattern: Enter a pattern, flags and some test text in the live tester to see the matches highlighted using your browser's regex engine. FAQ: Q: What is the difference between greedy and lazy quantifiers? A: Greedy quantifiers like * and + match as much as possible, then backtrack if needed. Adding a ? makes them lazy, so *? and +? match as little as possible. Possessive quantifiers like *+ match greedily and never backtrack, which can prevent catastrophic backtracking. Q: Do all flavors support lookbehind? A: Lookbehind ((?<=...) and (?...), lookahead, and lookbehind are supported in patterns. In the replacement you can reference numbered groups with $1, $2 or named groups with $. Q: What does the match count tell me? A: It shows how many times the pattern matched the input, which is a quick way to confirm your expression is hitting the intended spots before you trust the replaced output. Q: My pattern is not matching — what is wrong? A: Common causes are forgetting to escape special characters (. + * ? etc.), missing the global flag for multiple matches, or needing the multiline (m) flag for ^ and $ to match line boundaries. Adjust the flags or escape the literals. #### ISO Country Codes Reference URL: https://geratools.com/iso-country-codes-reference Free ISO 3166-1 country code reference — search alpha-2, alpha-3 and numeric codes for every country. Runs entirely in your browser, nothing is uploaded. How to use: 1. Type what you know: Enter a country name, a two- or three-letter code, or a numeric code in the search box. 2. Scan the table: Matching rows show the alpha-2, alpha-3 and three-digit numeric codes side by side. 3. Copy the code you need: Select the code value directly from the table for use in forms, APIs or spreadsheets. FAQ: Q: What is the difference between alpha-2 and alpha-3 codes? A: Alpha-2 codes are two letters (for example GB) and are used in domains and most web APIs. Alpha-3 codes are three letters (GBR) and are used where extra clarity is needed, such as ISO documents and some banking systems. Both come from the ISO 3166-1 standard. Q: What are the numeric country codes for? A: The three-digit numeric codes are script-independent, so they work the same in any writing system. They are common in statistical and government datasets where letter codes might be ambiguous. Q: Is the alpha-2 code the same as the country domain? A: Almost always. Country-code top-level domains (ccTLDs) like .de or .jp are based on the ISO 3166-1 alpha-2 code. The notable exception is the United Kingdom, whose code is GB but whose domain is .uk. Q: What is the alpha-2 code for the UK? A: The ISO 3166-1 alpha-2 code for the United Kingdom is GB, and the alpha-3 code is GBR, with numeric 826. The .uk domain is a historical exception that does not match the ISO code. Q: Do country codes ever change? A: Yes, occasionally. When a country is renamed or formed, ISO updates 3166-1 — for example South Sudan was added as SS/SSD in 2011. This reference reflects the current standard codes. Q: Is my search sent anywhere? A: No. The full code list ships with the page and every lookup happens in your browser, so nothing you type is uploaded. #### International Calling Codes Reference URL: https://geratools.com/calling-codes-reference Free international calling code reference — search the E.164 country dialling code for any country by name, ISO code or number. Runs entirely in your browser. How to use: 1. Enter a country or code: Type a country name, its ISO code, or a dial code such as 44 into the search box. 2. Find the calling code: The matching row shows the international dialling prefix, including the leading plus sign. 3. Dial internationally: Replace the plus with your own exit code (such as 00) or keep the plus when saving the number to a mobile. FAQ: Q: What does the plus sign in a calling code mean? A: The plus is a placeholder for your local international access (exit) code. On mobiles you can dial the plus directly; on landlines you usually replace it with a prefix like 00 or 011. Q: Why do the US, Canada and Caribbean share +1? A: They belong to the North American Numbering Plan, a single shared dialling scheme. Individual territories are distinguished by their three-digit area codes rather than separate country codes. Q: Is my search private? A: Yes. The full list of calling codes ships with the page, so every lookup happens locally and nothing is sent to a server. Q: How do I dial an international number correctly? A: Dial your exit code (or the plus on a mobile), then the country calling code, then the national number — usually dropping the leading 0 of the local number. For example, a UK number 020 7946 0000 becomes +44 20 7946 0000. Q: What is the difference between a country calling code and an area code? A: The calling code (such as +44 or +1) routes a call to the correct country. The area code is part of the national number and routes within that country. You dial the calling code first, then the area code. Q: Which country has the calling code +44? A: The United Kingdom uses +44. Other common examples are +1 for the USA and Canada, +33 for France, +49 for Germany, +91 for India and +86 for China. Q: Are calling codes the same as ISO country codes? A: No. Calling codes (E.164, e.g. +44) are for telephone dialling. ISO 3166 codes (e.g. GB, GBR) identify countries in data and software. This tool also lets you search by ISO code to find the matching calling code. #### Time Zone List Reference URL: https://geratools.com/timezone-list-reference Free time zone reference — search IANA time zone identifiers and their UTC offsets by city, region or offset. Runs entirely in your browser, nothing is uploaded. How to use: 1. Search a city or region: Type a city, a region such as Europe, or an offset like +05:30 into the search box. 2. Read the offset: Each match shows the IANA identifier and its standard (winter) UTC offset. 3. Use the identifier: Copy the IANA name (for example Asia/Tokyo) for use in code, calendars or server configuration. FAQ: Q: Why do you call these IANA time zones? A: IANA maintains the tz database, the canonical list of zone identifiers such as Europe/London used by operating systems and programming languages. Naming a zone by city avoids the ambiguity of abbreviations like CST. Q: Do the offsets include daylight saving time? A: The offsets shown are the standard (winter) offset. Many zones move forward an hour in summer for daylight saving, so the live offset can differ for part of the year. Q: Is the lookup done on a server? A: No. The zone list is bundled with the page and all searching happens in your browser. Q: What does an identifier like Asia/Kolkata mean? A: It is a Region/City pair from the tz database. The region groups by continent or ocean, and the city is a representative location whose historical and current rules define the zone. Q: Why not just use abbreviations like EST or CST? A: Abbreviations are ambiguous — CST can mean Central US, China, or Cuba time. IANA Region/City names are unique and carry the full daylight-saving history, which is why software uses them. Q: Can I search by UTC offset? A: Yes. Type an offset such as +05:30 or -08:00 to find zones at that standard offset, alongside searching by city or region. Q: Where can I use these identifiers? A: Anywhere that accepts an IANA zone — JavaScript Intl and Date, Python zoneinfo, Java, cron and server configs, and calendar apps. Copy the exact Region/City string. #### File Extensions Reference URL: https://geratools.com/file-extensions-reference A searchable file extensions reference grouped by documents, images, audio and video, archives, code and system files — each with a plain-English description. Runs entirely in your browser, nothing is uploaded. How to use: 1. Browse by category: Extensions are grouped by type — documents, images, audio and video, archives, code and system files — so you can scan the right area quickly. 2. Search for an extension: Type an extension with or without the leading dot, or part of a description, to filter the list instantly. 3. Read the description: Each row shows the extension and a short plain-English description of the file format. FAQ: Q: Is a file extension the same as a file type? A: Not exactly. The extension is the part of the name after the last dot and is just a hint to the operating system. The true file type is determined by the file's actual contents, which is why renaming an extension does not convert the file. Q: What is the difference between .jpg and .png? A: JPG uses lossy compression that is ideal for photographs and small file sizes but discards some detail. PNG uses lossless compression, supports transparency, and is better for logos, screenshots and graphics with sharp edges. Q: Is anything I search sent to a server? A: No. The full list and the search both run entirely in your browser — nothing you type is uploaded anywhere. Q: Why can't I open a file even though it has a familiar extension? A: An extension only tells the OS which program to try. If the file is corrupt, encrypted, or actually a different format with a renamed extension, the matching program may still fail to open it. Renaming an extension never converts the underlying data. Q: How do I open an unknown file extension safely? A: Look up the extension here to identify the likely format and the program that handles it. Be cautious with executable types (.exe, .bat, .sh) from untrusted sources, since opening them runs code. Q: What is the difference between .zip and .tar.gz? A: Both bundle multiple files into one archive. .zip compresses each file individually and is native on Windows and macOS. .tar.gz first tars files into one stream and then gzip-compresses the whole thing, which is common on Linux and often gives slightly better compression. #### Markdown Syntax Reference URL: https://geratools.com/markdown-syntax-reference A searchable Markdown syntax reference — headings, emphasis, lists, links, images, code blocks, tables and more — with plain-English meanings. Runs entirely in your browser. How to use: 1. Search for syntax: Type a keyword or symbol, such as bold, table, link or code. 2. Read the meaning: Each entry shows the Markdown syntax and what it produces. 3. Browse by group: Syntax is grouped into headings, emphasis, lists, links, code and other blocks. FAQ: Q: How do I make text bold or italic in Markdown? A: Wrap text in single asterisks or underscores for italic (*italic* or _italic_), double for bold (**bold**), and triple for both (***bold italic***). Strikethrough uses double tildes (~~text~~) in GitHub Flavored Markdown. Q: How do I write a table in Markdown? A: Use pipes to separate columns, for example | a | b |, then add a separator row of dashes (| --- | --- |) below the header row. Each following row is a data row. Tables are a GitHub Flavored Markdown feature. Q: Is any data sent anywhere? A: No — this is a static reference that runs entirely in your browser. Nothing is uploaded. Q: How do I add a link or an image in Markdown? A: A link is [text](url), and a link with a hover title is [text](url "title"). An image is the same with a leading exclamation mark — ![alt text](url). A bare URL in angle brackets, , becomes a clickable autolink. Q: How do I write a code block in Markdown? A: Wrap a single span in backticks for inline code (`code`). For a block, put three backticks on their own line before and after the code. Add a language after the opening fence (```js) so renderers apply syntax highlighting. Indenting four spaces also makes a code block. Q: What is GitHub Flavored Markdown? A: GitHub Flavored Markdown (GFM) is a superset of standard Markdown that adds tables, task lists ( - [ ] and - [x] ), strikethrough (~~text~~) and autolinking. This reference flags GFM-only items so you know which features may not render in stricter Markdown engines. Q: How do I create a task list checkbox? A: Use a list item with a bracketed space for unchecked ( - [ ] task ) and a bracketed x for checked ( - [x] task ). These render as interactive checkboxes on GitHub and other GFM-aware platforms. #### Unicode Blocks Reference URL: https://geratools.com/unicode-blocks-reference A developer reference of common Unicode blocks, listing each block name, its hexadecimal code-point range and the characters it contains. Searchable and fully client-side — nothing is uploaded. How to use: 1. Search a block: Type a block name, a hex range like U+2200, or content keywords such as emoji. 2. Read the range: Each row shows the start and end code points of the block in hexadecimal. 3. Identify a character: Match a character's code point to the range it falls within to learn its block. FAQ: Q: What is a Unicode block? A: A Unicode block is a contiguous range of code points reserved for a related set of characters, such as Basic Latin, Cyrillic or Emoticons. Each block has a name and a fixed hexadecimal range. Q: How do I read a code point like U+1F600? A: The U+ prefix denotes a Unicode code point written in hexadecimal. U+1F600 is the grinning-face emoji, which falls inside the Emoticons block U+1F600 to U+1F64F. Q: Is this list exhaustive? A: No. It covers the most commonly used blocks for everyday text and emoji. The full Unicode standard defines several hundred blocks. No data is sent anywhere. Q: Which block are emoji in? A: There is no single emoji block. Face emoji live in Emoticons (U+1F600–U+1F64F), many objects and symbols in Miscellaneous Symbols and Pictographs (U+1F300–U+1F5FF), travel symbols in Transport and Map Symbols (U+1F680–U+1F6FF), and newer emoji in Supplemental Symbols and Pictographs (U+1F900–U+1F9FF). Q: What is the difference between a Unicode block and a script? A: A block is a fixed contiguous range of code points, while a script (like Latin or Cyrillic) is a writing system whose characters may be spread across several blocks. The two often overlap but are not the same concept. Q: Why are Chinese, Japanese and Korean characters in one block? A: CJK Unified Ideographs (U+4E00–U+9FFF) holds the Han characters shared across Chinese, Japanese and Korean. Because the scripts share thousands of common ideographs, Unicode unified them into one block rather than duplicating each. Q: How do I find which block a character belongs to? A: Find the character's code point, then locate the block whose start and end range contains it. For example U+20AC (the euro sign) sits between U+20A0 and U+20CF, so it is in the Currency Symbols block. #### ASCII Control Codes Reference URL: https://geratools.com/ascii-control-codes-reference A searchable reference for the ASCII control codes 0–31 and DEL (127) with each one's abbreviation, name, caret notation, escape sequence and purpose. Runs entirely in your browser, nothing is uploaded. How to use: 1. Search a control code: Type a decimal value, an abbreviation like LF, a name, or an escape such as \n to filter the list. 2. Read the notation columns: Each row shows the decimal and hex value, the abbreviation, caret notation, any escape sequence, the full name and what the code does. 3. Map keystrokes to codes: Use the caret column to see the Ctrl key combination — for example ^C is ETX (3) and ^M is carriage return (13). FAQ: Q: How many ASCII control characters are there? A: There are 33: the 32 codes from 0 to 31 (the C0 control set) plus DEL at 127. They are non-printing characters that control devices and data streams rather than displaying a glyph. Q: What is the difference between CR and LF? A: Carriage return (CR, 13, \r) returns the cursor to the start of the line, while line feed (LF, 10, \n) moves down one line. Unix uses LF for newlines, classic Mac used CR, and Windows uses CR LF together. Q: What is caret notation? A: Caret notation writes a control code as a caret (^) followed by a printable letter, representing the Ctrl key combination that produces it. For example ^C is ETX (3), ^I is tab (9), and ^M is carriage return (13). Q: What is the DEL character? A: DEL is decimal 127 (0x7F). Historically it punched out all the holes on paper tape to "delete" a character. It sits outside the 0-31 C0 range but is still treated as a control character. Q: Is anything I search uploaded? A: No. The full list of control codes and the search both run entirely in your browser. Nothing you type is sent anywhere. ### ID & Number Validators #### Clipboard Contents Security Checker URL: https://geratools.com/clipboard-security-checker With your explicit permission via the Clipboard API, read the current clipboard contents and scan locally for API keys, JWTs, private keys, credit card numbers (Luhn-validated), emails, and other PII patterns — warning you before you paste something sensitive into a form, chat, or document. All scanning runs in your browser; nothing is sent anywhere. How to use: 1. Grant clipboard read permission: Click the scan button. Your browser asks permission to read the clipboard; approve it so the tool can inspect the current contents. 2. Or paste manually: If your browser blocks programmatic clipboard reads, paste the text into the box instead — the same local scan runs on it. 3. Review the findings: Read the flagged secret and PII patterns. If anything sensitive is detected, clear or redact it before pasting elsewhere. FAQ: Q: Does this tool send my clipboard anywhere? A: No. The clipboard text is read into the page and all pattern matching happens in your browser with JavaScript. Nothing is uploaded, logged, or stored, which is the whole point of a paste-safety check. Q: What does it detect? A: It flags common secret formats — AWS keys, generic API tokens, JWTs, PEM private keys, Slack/GitHub tokens — plus credit card numbers validated with the Luhn algorithm, email addresses, IBANs, and other PII patterns. Each finding shows the type and a redacted preview. Q: Why does it need clipboard permission? A: Reading the clipboard programmatically is a privileged action, so the browser prompts for consent. If you prefer not to grant it, or the browser refuses, just paste the text into the box and the identical scan runs locally. Q: Are credit card matches reliable? A: Numbers are first matched by length and digit grouping, then validated with the Luhn check digit, which removes most false positives. It still cannot confirm a card is real or active — it only flags strings that look like valid card numbers so you do not paste them by accident. Q: Can it give false positives? A: Yes. Pattern-based detection is conservative on purpose — it would rather warn you about a harmless high-entropy string than miss a real secret. Treat findings as a prompt to look, not as proof a credential is exposed. #### Damm Algorithm Checker URL: https://geratools.com/damm-check Validate any decimal number with the Damm check-digit algorithm, or generate the missing check digit. Detects all single-digit and adjacent-transposition errors. Runs entirely in your browser. How to use: 1. Choose validate or generate: Pick "Validate" to test a number that already includes a check digit, or "Generate" to compute the check digit for a payload. 2. Enter the digits: Type or paste a decimal number. Only digits 0–9 are accepted; everything runs locally. 3. Read the result: Validation shows valid or invalid; generation shows the single check digit and the full protected number. FAQ: Q: What is the Damm algorithm? A: It is a check-digit method published by H. Michael Damm in 2004 that uses a totally antisymmetric quasigroup of order 10. It produces a single decimal check digit and detects all single-digit and adjacent-transposition errors. Q: How is the Damm check digit computed? A: Start with an interim value of 0, then for each payload digit set interim = table[interim][digit] using the standard 10x10 quasigroup. The final interim value is the check digit to append. Q: How does validation work? A: Run the same table lookup over the full number including its check digit. The number is valid if and only if the final interim value is 0. Q: Why use Damm instead of Luhn or mod-11? A: Damm needs no special symbols (mod-11 can require an X) and, unlike basic Luhn, detects all adjacent transpositions as well as all single-digit errors with one decimal digit. Q: Is my number sent to a server? A: No. The entire calculation happens in your browser, so the number you enter never leaves your device. #### EAN-13 / UPC-A Barcode Validator URL: https://geratools.com/ean13-validator Validate EAN-13 (13-digit) and UPC-A (12-digit) retail barcodes with the correct mod-10 check digit, auto-detecting the type by length and showing the expected check digit on failure. Runs entirely in your browser. How to use: 1. Enter the barcode: Type or paste the digits. 13 digits are treated as EAN-13 and 12 digits as UPC-A; spaces and hyphens are ignored. 2. Read the verdict: The tool applies the matching mod-10 algorithm and shows valid or invalid along with the weighted sum. 3. Use the expected check digit: If validation fails, the correct check digit for the leading digits is shown so you can correct a typo. FAQ: Q: How is an EAN-13 check digit calculated? A: Multiply the 13 digits by alternating weights starting with 1 then 3 from the left (odd positions weight 1, even positions weight 3), sum the products, and the barcode is valid if the total is divisible by 10. Q: How does UPC-A differ from EAN-13? A: UPC-A is 12 digits and weights the odd positions by 3 and even positions by 1, which is the mirror of EAN-13. A UPC-A is identical to an EAN-13 with a leading zero, so the two encode the same product. Q: What is a GTIN? A: GTIN (Global Trade Item Number) is the umbrella term for these identifiers. GTIN-13 is an EAN-13 and GTIN-12 is a UPC-A; both use a trailing mod-10 check digit. Q: Can I compute a missing check digit? A: Yes. If the check digit is wrong, the tool shows the expected check digit derived from the leading 11 (UPC-A) or 12 (EAN-13) digits. Q: Is my barcode sent to a server? A: No. The checksum runs entirely in your browser, so the barcode never leaves your device. #### IMEI Number Validator URL: https://geratools.com/imei-validator Validate a 15-digit mobile IMEI with the Luhn check-digit algorithm, see the TAC and serial breakdown, and get the correct check digit if it fails. Runs entirely in your browser — nothing is uploaded. How to use: 1. Find your IMEI: Dial *#06# on the phone, or read it from the SIM tray or device settings. It is 15 digits long. 2. Enter the IMEI: Type or paste the 15 digits. Spaces and hyphens are ignored and everything runs locally. 3. Read the result: The tool runs the Luhn check, shows valid or invalid, and breaks out the TAC and serial portions. FAQ: Q: How is an IMEI validated? A: The 15th digit is a Luhn check digit over the first 14. Doubling every second digit from the right, subtracting 9 where the result exceeds 9, and summing all digits including the check digit must produce a total divisible by 10. Q: What is the TAC in an IMEI? A: The TAC (Type Allocation Code) is the first 8 digits and identifies the device model and manufacturer. The next 6 digits are the device serial, and the 15th is the Luhn check digit. Q: Does a valid IMEI mean the phone is not stolen? A: No. A passing Luhn check only confirms the number is well-formed. Whether a device is blacklisted or reported stolen requires a carrier or GSMA database lookup, which this tool does not perform. Q: My IMEI has 16 digits, why? A: A 16-digit value is an IMEISV, which appends a 2-digit software version. Drop the final two digits to get the 15-digit IMEI this validator expects. Q: Is my IMEI sent anywhere? A: No. The Luhn calculation runs entirely in your browser, so your IMEI never leaves your device. #### IP Address Type & Privacy Checker URL: https://geratools.com/ip-address-type-checker Classify any IPv4 or IPv6 address against the IANA special-use registries — RFC 1918 private, RFC 4193 ULA, loopback, link-local, multicast, and documentation ranges. See whether it is globally routable and what it reveals if it leaks. Runs entirely in your browser. How to use: 1. Enter an IP address: Type or paste any IPv4 dotted-quad or IPv6 address, with or without compression and brackets. 2. Read the classification: The tool matches the address against IANA special-use ranges and names its category, such as private, loopback, or globally routable. 3. Check what it reveals: See whether the address is publicly routable and what topology or geolocation information it would expose if logged or shared. FAQ: Q: How do I know if an IP is public or private? A: Private IPv4 ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 (RFC 1918); private IPv6 is fc00::/7 (RFC 4193). Anything outside the reserved ranges is a public, globally routable address. This tool checks all the reserved ranges and tells you which bucket the address falls into. Q: Why does a private IP not reveal my location? A: Private addresses such as 192.168.1.10 are reused on millions of separate networks behind NAT, so they cannot be routed to or geolocated on the public internet. A public IP, by contrast, is unique and can be mapped to an ISP and rough region. Q: What is a link-local or APIPA address? A: An address in 169.254.0.0/16 (IPv4) or fe80::/10 (IPv6) is auto-assigned when no DHCP server responds. It only works on the local network segment and is never routed, so seeing one usually signals a network configuration problem. Q: What are the documentation IP ranges? A: RFC 5737 reserves 192.0.2.0/24, 198.51.100.0/24, and 203.0.113.0/24 for IPv4, and RFC 3849 reserves 2001:db8::/32 for IPv6, exclusively for examples and documentation. They should never appear in live traffic, so spotting one means it is placeholder data. Q: Is the address I enter sent anywhere? A: No. The classification is computed purely from the address bits against the built-in IANA range tables. Nothing is looked up online, so the address you check never leaves your browser. #### IP (Ingress Protection) Rating Lookup URL: https://geratools.com/ip-rating-lookup Decode any IEC 60529 IP rating: the first digit gives solid-particle (dust) protection and the second gives water ingress protection. Type an IP code like IP67 to read both levels in plain English. How to use: 1. Enter the IP code: Type a rating such as IP54, IP67 or IPX8 into the box. The IP prefix is optional. 2. Read both digits: The first digit decodes solid-particle (dust) protection; the second decodes water protection. 3. Handle X placeholders: An X means that level was not tested, for example IPX7 specifies water protection only. FAQ: Q: What do the two digits in an IP rating mean? A: The first digit (0–6) rates protection against solid objects and dust, where 6 means fully dust-tight. The second digit (0–9K) rates protection against water, from dripping up to high-pressure jets and immersion. Q: What does the X mean in IPX7? A: X is a placeholder meaning that characteristic was not rated. IPX7 means the device was tested for water (immersion to 1 m) but its dust protection was not specified or claimed. Q: Is IP67 better than IP68? A: For water, IP68 is higher: it covers continuous immersion beyond 1 m at a depth the manufacturer specifies, whereas IP67 covers temporary immersion to 1 m for 30 minutes. Both share the maximum dust rating of 6. Q: What is the difference between IP69 and IP69K? A: They describe the same test: protection against close-range high-temperature, high-pressure water jets. IP69K is the original German DIN 40050-9 designation; recent IEC 60529 editions adopted it as level 9. Q: Does this lookup work offline? A: Yes. The full IEC 60529 digit tables are built into the page and decoding runs entirely in your browser. Nothing is uploaded or stored. #### ISBN-10 to ISBN-13 Converter URL: https://geratools.com/isbn10-to-isbn13 Convert a valid ISBN-10 book number into its ISBN-13 equivalent by prefixing 978 and recomputing the modulo-10 check digit. Validates the original ISBN-10 check digit first, handles the X check character, and offers hyphenated output. Runs in your browser. How to use: 1. Enter the ISBN-10: Type the 10-character ISBN, with or without hyphens. The final character may be X, which represents the value 10. 2. Let it validate: The tool first checks the ISBN-10 modulo-11 check digit and refuses to convert an invalid number, so you never get a meaningless result. 3. Read the ISBN-13: See the converted 13-digit ISBN with its recomputed check digit, optionally grouped with hyphens, and copy it to the clipboard. FAQ: Q: How does ISBN-10 become ISBN-13? A: You drop the ISBN-10 check digit, prefix the EAN code 978 to the remaining 9 digits, then compute a fresh ISBN-13 check digit. The first nine significant digits are otherwise unchanged. Q: Why does the new check digit differ from the old one? A: ISBN-10 uses a modulo-11 checksum with weights 10 down to 1, while ISBN-13 uses a modulo-10 checksum with alternating weights 1 and 3. Different schemes over different digits produce different check digits. Q: What does the X in an ISBN-10 mean? A: The ISBN-10 check digit can be 0 through 10, and 10 is written as the letter X because it needs a single character. The tool accepts X and treats it as the value 10 when validating. Q: Can every ISBN-10 be converted? A: Yes. Every valid ISBN-10 maps to exactly one ISBN-13 using the 978 prefix. The reverse is not true, because newer ISBN-13 numbers using the 979 prefix have no ISBN-10 equivalent. Q: Is the hyphenation accurate? A: The hyphenated grouping shown is illustrative. Correct group, registrant, and publication boundaries depend on the registration agency and vary by length, so always use the publisher's official hyphenation for print. #### ISBN-13 Validator & Check Digit URL: https://geratools.com/isbn13-validator Validate any ISBN-13 using the EAN-13 mod-10 check-digit algorithm, or enter the first 12 digits to compute the check digit. Recognises 978/979 prefixes, ignores hyphens, and runs entirely in your browser. How to use: 1. Enter the ISBN-13: Type or paste the 13-digit ISBN, with or without hyphens. To compute a check digit instead, enter the first 12 digits. 2. Read the verdict: The tool applies the EAN-13 mod-10 algorithm and shows valid or invalid plus the weighted sum. 3. Check the prefix and check digit: It also flags whether the prefix is the expected 978 or 979 and shows the correct check digit if validation fails. FAQ: Q: How is an ISBN-13 check digit calculated? A: Multiply the 13 digits by alternating weights of 1 and 3 starting with 1 on the left, sum the products, and the ISBN is valid if the total is divisible by 10. The check digit is (10 minus sum-mod-10) mod 10. Q: What is the difference between ISBN-10 and ISBN-13? A: ISBN-13 is 13 digits and uses the EAN-13 mod-10 algorithm, while ISBN-10 is 10 characters and uses a mod-11 scheme. ISBN-13 has been the standard for new books since 2007 and always starts with 978 or 979. Q: What do the 978 and 979 prefixes mean? A: They are the GS1 prefixes that turn a book identifier into a valid EAN-13 barcode. 978 is the original Bookland prefix; 979 was added once 978 numbers ran low. Q: Can I generate a missing check digit? A: Yes. Enter just the first 12 digits and the tool shows the correct check digit and the complete 13-digit ISBN. Q: Is my ISBN uploaded anywhere? A: No. The calculation runs entirely in your browser, so nothing is sent to a server. #### ISO-8859-1 / Latin-1 Encoder URL: https://geratools.com/latin1-encode Convert text encodable in ISO-8859-1 (Latin-1) to its single-byte hex representation and decode Latin-1 hex back to text. Latin-1 maps Unicode U+0000 to U+00FF directly onto bytes, covering Western European accented letters. Runs in your browser. How to use: 1. Pick a direction: Choose text to Latin-1 hex to encode, or Latin-1 hex to text to decode. 2. Enter your data: Type text to encode, or paste space-separated hex bytes such as 43 61 66 E9 to decode. 3. Copy the output: Copy the resulting hex bytes or recovered text for data files, protocols, or debugging. FAQ: Q: What is ISO-8859-1? A: ISO-8859-1, also called Latin-1, is an 8-bit encoding for Western European languages. It is the simplest legacy encoding because each byte value from 0x00 to 0xFF maps directly to the Unicode codepoint of the same number. Q: How does it relate to Unicode? A: The first 256 Unicode codepoints, U+0000 to U+00FF, were deliberately defined to match ISO-8859-1. That is why Latin-1 encoding is a direct identity map and why it appears so often in older systems and HTTP defaults. Q: Why are some characters dropped? A: Latin-1 has only 256 slots. Characters with a Unicode codepoint above U+00FF, such as the euro sign, curly quotes, or emoji, have no Latin-1 byte. The tool reports these as skipped rather than encoding them wrongly. Q: How is Latin-1 different from Windows-1252? A: They agree on 0x00 to 0x7F and 0xA0 to 0xFF. The difference is the 0x80 to 0x9F range, which Latin-1 reserves for control codes while Windows-1252 uses it for printable symbols. Mixing them up causes mojibake. Q: When would I use Latin-1 today? A: Latin-1 still appears as a default in some HTTP headers, older databases, email systems, and protocols. When decoding legacy data, knowing it is Latin-1 lets you recover accented Western European text correctly. #### Luhn Algorithm Checker URL: https://geratools.com/luhn-check Validates any number with the Luhn (mod 10) algorithm and computes the correct check digit. Works for credit cards, IMEI numbers and many national IDs, showing the weighted sum and why a number passes or fails. How to use: 1. Enter the number: Type or paste the number to check; spaces and dashes are ignored. 2. Read valid or invalid: The tool runs the Luhn mod-10 test and reports whether the number passes. 3. Inspect the check digit: See the expected check digit and the digit you would append to make a valid number. FAQ: Q: What is the Luhn algorithm? A: The Luhn algorithm, also called mod 10, is a checksum formula that validates identification numbers such as credit cards and IMEIs. It doubles every second digit from the right, sums the digits, and a valid number has a total divisible by 10. Q: How is the Luhn check digit calculated? A: Treat the payload as if a 0 check digit were appended, run the Luhn sum, then the check digit equals (10 - (sum mod 10)) mod 10. This is the single digit that makes the whole number pass. Q: Which numbers use Luhn? A: Credit and debit card numbers (the final digit), IMEI device identifiers, some social insurance numbers and many other identifiers use Luhn as a built-in typo-detection check. Q: Does a valid Luhn result mean the card is real? A: No. Luhn only confirms the digits are internally consistent, catching most typos and transpositions. It does not confirm the card was ever issued, is active, or has funds. Never treat it as authorization. Q: What errors does Luhn catch? A: Luhn detects all single-digit errors and almost all adjacent transposition errors (swapping two neighbouring digits), except the specific swap of 0 and 9, which it misses. #### Luhn Algorithm Checker URL: https://geratools.com/luhn-checker Free Luhn algorithm checker. Validate credit card and other MOD-10 numbers, see the exact check-digit calculation, detect the card brand, and generate fictitious Luhn-valid test numbers. Runs entirely in your browser. How to use: 1. Enter the number: Type or paste a card number or any MOD-10 number, with or without spaces and dashes. 2. Read the result: The tool shows pass or fail, the Luhn sum, the expected check digit, and the detected card brand. 3. Generate a test number: Pick a brand and generate a fictitious but Luhn-valid number to test your own form validation. FAQ: Q: What is the Luhn algorithm? A: The Luhn algorithm, also called the mod-10 algorithm, is a simple checksum used to catch accidental errors in identification numbers. Starting from the right, every second digit is doubled (subtracting 9 if over 9), all digits are summed, and the number is valid if the total is a multiple of 10. Q: Does a valid Luhn check mean the card is real? A: No. The Luhn check only confirms the number is internally consistent and free of common typos. It says nothing about whether the card exists, is active, or has funds. Only the card network can confirm that. Q: Why does the tool show an expected check digit? A: The check digit is the final digit, chosen so the whole number passes Luhn. If your number fails, the expected check digit tells you what that last digit should have been, which usually reveals a single mistyped or transposed digit. Q: Are the generated numbers real cards? A: No. Generated numbers are fictitious — they only satisfy the Luhn rule and a brand prefix so you can test input validation and formatting. They are not issued to anyone and cannot be charged. Q: Is my card number sent anywhere? A: No. Validation and generation happen entirely in your browser. Nothing is transmitted, which makes the tool safe to use even with a real card number you only want to syntax-check. #### OpenAPI / Swagger Spec Validator URL: https://geratools.com/openapi-validator Free OpenAPI and Swagger validator. Parses your YAML or JSON spec and checks the required structure — version, info, paths, operations, responses and parameters — reporting each issue with a JSON-pointer-style path. Client-side; the spec is never uploaded. How to use: 1. Paste your spec: Drop an OpenAPI 3.x or Swagger 2.0 document in YAML or JSON into the text area. A sample Pet Store spec is preloaded. 2. Read the result: The validator detects the version and reports whether the spec is structurally valid or lists each problem found. 3. Fix the flagged paths: Each issue includes a JSON-pointer-style location such as paths/pets/get/responses so you can jump straight to it. FAQ: Q: What does this validator check? A: It checks the structural rules of the spec — the version field, a valid info object with title and version, a paths object, that every operation has a responses object, that response keys are valid status codes or default, and that inline parameters declare name and in. It catches the most common spec mistakes. Q: Does it accept both YAML and JSON? A: Yes. JSON is parsed directly, and block-style YAML is parsed by a built-in parser covering the indentation, key-value, and list structures that appear in typical OpenAPI documents. Paste whichever format you have. Q: What is the difference between OpenAPI and Swagger? A: Swagger 2.0 is the older specification, identified by a top-level swagger field set to 2.0. OpenAPI 3.x is the successor, identified by an openapi field like 3.0.3. This tool detects and validates either, and shows you which one it found. Q: Does it resolve external $ref references? A: No. It validates the structure of the document you paste, including local references, but it does not fetch or dereference external files since everything runs in your browser. Parameters that are pure references are accepted as-is. Q: Is my API spec uploaded anywhere? A: No. Parsing and validation happen entirely in your browser in JavaScript. The spec never leaves your device, which makes it safe for private or internal API definitions. #### API Rate-Limit Header Calculator URL: https://geratools.com/rate-limiting-calculator Free API rate-limit calculator. Set requests per window, window duration, and burst allowance, then simulate a request sequence to see the exact X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, and Retry-After header values, including which requests get HTTP 429. How to use: 1. Set your policy: Enter the requests allowed per window, the window duration in seconds, and any burst allowance on top of the base limit. 2. Describe the traffic: Choose how many requests to simulate and the interval between them to mimic a client hitting your API. 3. Read the header table: The tool shows, per request, whether it returns 200 or 429 and the X-RateLimit-Remaining, X-RateLimit-Reset, and Retry-After values your server would emit. FAQ: Q: What do the X-RateLimit headers mean? A: X-RateLimit-Limit is the maximum requests allowed in the current window, X-RateLimit-Remaining is how many you have left, and X-RateLimit-Reset is when the window resets (here shown as seconds remaining). They let clients self-throttle before hitting a 429. Q: When should I send the Retry-After header? A: Send Retry-After only with a 429 Too Many Requests (or 503) response. It tells the client how many seconds to wait before retrying. This tool sets it to the number of seconds until the current fixed window resets, rounded up. Q: What is a burst allowance? A: A burst allowance is extra capacity on top of your steady-state limit, letting clients briefly exceed the base rate to absorb spikes. In this tool the effective cap shown in X-RateLimit-Limit is the base limit plus the burst, and requests beyond that cap in a window are rejected. Q: Does this use a fixed window or sliding window? A: It models a fixed-window limiter: the counter resets at the start of each window, which is simple and matches many gateways. Fixed windows can allow up to twice the limit across a window boundary; if that matters, consider a sliding-window or token-bucket algorithm. Q: Should rate limits be per IP, per user, or per API key? A: It depends on your threat model. Per-API-key limits are usual for authenticated APIs because they map to a billable identity; per-IP limits protect unauthenticated endpoints but can punish users behind shared NAT. Many APIs combine both, applying the stricter of the two. #### SPF Record Builder & Syntax Checker URL: https://geratools.com/spf-record-builder Build a syntactically valid SPF TXT record from IP ranges, include mechanisms, and an all-policy through a guided form. Validates IPv4/IPv6/CIDR, counts the 10-DNS-lookup limit, and warns near the 255-byte TXT cap. Fully offline — no DNS query is made. How to use: 1. List your sending sources: Enter the IPv4/IPv6 addresses that send your mail and the include domains of any email providers (e.g. _spf.google.com, sendgrid.net). 2. Choose mechanisms and policy: Tick mx or a if those records also send mail, then pick an all policy — start with ~all (softfail) while testing, then move to -all once confident. 3. Copy the record and check warnings: Copy the generated TXT string and publish it. Heed any warnings about the 10-lookup limit or the 255-byte cap before going live. FAQ: Q: What does the 'all' mechanism do? A: It is the catch-all that matches any sender not matched by an earlier mechanism. The qualifier sets the policy: -all rejects them (Fail), ~all accepts but marks them (SoftFail), ?all is Neutral, and +all authorises everyone — which disables SPF and should never be used. Q: Why does SPF have a 10-lookup limit? A: Each a, mx, include, exists, and ptr mechanism triggers a DNS lookup during evaluation. The SPF spec caps these at 10 to prevent denial-of-service amplification. Exceeding 10 produces a PermError and your SPF effectively fails, so the builder counts them for you. Q: Can I have more than one SPF record? A: No. A domain must publish exactly one SPF TXT record. Two SPF records cause a PermError. If you use multiple providers, combine them into a single record with several include mechanisms. Q: What is the 255-byte limit about? A: A single character string inside a TXT record cannot exceed 255 bytes. Longer records must be split into multiple quoted strings within the same TXT entry, which DNS concatenates. The builder warns as you approach the limit so you can plan for it. Q: Where do I publish the SPF record? A: As a TXT record at the domain itself (the apex host, for example example.com), not at a subdomain like _spf. The value is the full string starting with v=spf1. Subdomains that send mail need their own SPF records. #### Luhn Algorithm Checker URL: https://geratools.com/luhn-algorithm-checker Free Luhn algorithm checker — validate credit card numbers, IMEI numbers, ICCIDs and any mod-10 checksum, and compute the check digit. Runs entirely in your browser; nothing is uploaded. How to use: 1. Paste your number: Type or paste the number you want to check — spaces and dashes are ignored. 2. Read the verdict: The tool instantly shows whether the number passes the Luhn mod-10 check. 3. Get the check digit: See the Luhn check digit that would make a payload valid, useful for generating test data. FAQ: Q: What is the Luhn algorithm used for? A: The Luhn (mod-10) algorithm is a checksum used to catch typos in credit card numbers, IMEI numbers, SIM ICCIDs and many national identification numbers. It does not prove the number is real or active — only that it is internally consistent. Q: How do you calculate a Luhn check digit? A: Append a 0 to your payload, run the Luhn sum, then the check digit is (10 − (sum mod 10)) mod 10. This tool shows that digit for whatever you type, so you can build valid test numbers. Q: Does passing the Luhn check mean a card is valid? A: No. Passing only means the digits are mathematically consistent. It cannot confirm the card exists, is active, or belongs to anyone. It is purely a typo-detection check. Q: Which errors does the Luhn algorithm catch? A: It detects all single-digit errors and almost all transpositions of two adjacent digits. The one transposition it misses is swapping 09 with 90, because both produce the same doubled value. Q: What is the difference between Luhn (mod-10) and mod-97? A: Luhn is a mod-10 checksum used for card and device numbers, doubling every second digit. Mod-97 is a different, stronger scheme used for IBANs and some VAT numbers, dividing the whole number by 97. They are not interchangeable. Q: Is my number sent anywhere? A: No — the entire Luhn calculation runs in your browser. Nothing you type is uploaded, logged, or stored. #### IBAN Validator URL: https://geratools.com/iban-validator Free IBAN validator using the official mod-97 check — verify the country code, length and checksum of any International Bank Account Number. Runs entirely in your browser; nothing is uploaded. How to use: 1. Paste the IBAN: Enter the International Bank Account Number — spaces are ignored automatically. 2. Read the result: The tool runs the mod-97 checksum and shows whether the IBAN is valid. 3. Check the details: Review the detected country and the expected length for that country. FAQ: Q: How does IBAN validation work? A: The first four characters are moved to the end, letters are replaced with two-digit codes (A=10 to Z=35), and the resulting number is valid when it leaves a remainder of 1 when divided by 97. This is the ISO 13616 mod-97 check. Q: What are the two check digits in an IBAN? A: Characters 3 and 4 of every IBAN are the check digits. They are chosen so that the whole rearranged number passes the mod-97 test. They protect against typos and transposed digits but are not part of the bank or account number itself. Q: Why does the tool also check the length? A: Each country has a fixed total IBAN length — for example Germany is 22 characters and the UK is 22, while Norway is 15. A number can pass the mod-97 checksum yet still be the wrong length for its country, so the tool flags that separately. Q: Does a valid IBAN mean the account exists? A: No. The mod-97 check only confirms the IBAN is internally consistent and the length matches the country. It cannot confirm a real, open bank account or its holder. Q: How long is an IBAN? A: IBAN length varies by country, from 15 characters (Norway) up to 31 (Malta). The format is always a 2-letter country code, 2 check digits, then a country-specific account block. This tool knows the expected length for the major IBAN countries. Q: Is my IBAN sent anywhere? A: No — the mod-97 calculation runs entirely in your browser. Your IBAN is never uploaded, logged, or stored. #### Credit Card BIN Checker URL: https://geratools.com/credit-card-bin-checker Free credit card BIN checker — identify the issuing network (Visa, Mastercard, Amex and more) from the first 6-8 digits, with a Luhn check. Runs entirely in your browser; nothing is uploaded. How to use: 1. Enter the BIN: Type the first 6-8 digits of a card number — that is all the BIN check needs. 2. See the network: The tool matches the prefix against known network ranges and names the scheme. 3. Check length and Luhn: If you enter a full number, the expected length and Luhn mod-10 check are also shown. FAQ: Q: What is a BIN or IIN? A: The Bank Identification Number (BIN), also called the Issuer Identification Number (IIN), is the first 6-8 digits of a card number. Networks reserve known prefix ranges, so the BIN identifies the scheme such as Visa, Mastercard, Amex, Discover or UnionPay. Q: Can this tool reveal who owns a card? A: No. The BIN only identifies the card network from a public prefix table. It cannot reveal the cardholder, the bank account, or whether the card is active. Q: Which network does a card starting with 4 belong to? A: Visa. Visa cards always begin with 4. Mastercard starts with 51-55 or 2221-2720, American Express with 34 or 37, and Discover with 6011, 65, 644-649 or 622. Q: Do I have to enter a full card number? A: No — and you should not. The first 6-8 digits are enough to identify the network, and everything runs in your browser with nothing uploaded. #### EU VAT Number Validator URL: https://geratools.com/eu-vat-number-validator Free EU VAT number validator. Check the country prefix, length and character pattern of a VAT number for any of the 27 EU member states. Privacy-first and runs entirely in your browser — no VIES lookup, nothing is sent anywhere. How to use: 1. Enter the VAT number: Type or paste the VAT number including its 2-letter country prefix, e.g. DE123456789. 2. Read the result: The tool identifies the member state and checks the number against that country's documented length and character pattern. 3. Compare the formats: Open the reference list to see the expected VAT format for every EU country. FAQ: Q: Does this confirm the VAT number is registered? A: No. It only checks the structural format (prefix, length, character pattern). To confirm a number is registered and active, use the official EU VIES service. This tool performs no network lookup. Q: Why does Greece use the prefix EL instead of GR? A: For VAT purposes the EU uses EL as the country code for Greece, even though its ISO country code is GR. A Greek VAT number entered with GR will not be recognised — use EL followed by 9 digits. Q: What does an EU VAT number look like by country? A: It is always a 2-letter country prefix plus a body that varies by state — for example Germany is 9 digits (DE123456789), Austria is U plus 8 digits (ATU12345678), the Netherlands is 9 digits, a B, then 2 digits, and Italy is 11 digits. The tool's reference list shows all 27 patterns. Q: Why did my correctly registered VAT number fail the format check? A: The most common reasons are a missing country prefix, using GR instead of EL for Greece, or extra characters. This tool only checks structure, so a real number with the wrong format on screen will fail until the prefix and length are corrected. Q: How accurate is the format check? A: The patterns follow the official per-member-state VAT formats. A passing result means the number is well-formed; note that Greece uses the prefix EL (not GR) and some countries accept variable lengths. Q: Is my VAT number sent anywhere? A: No. This validator is privacy-first — every check runs locally in your browser and the number never leaves your device. #### ISBN Validator URL: https://geratools.com/isbn-validator Free ISBN validator for ISBN-10 and ISBN-13. Verify the check digit (mod-11 or mod-10) and convert between the two formats. Privacy-first and runs entirely in your browser — nothing is sent anywhere. How to use: 1. Enter the ISBN: Type or paste a 10- or 13-character ISBN. Hyphens and spaces are ignored, and an ISBN-10 may end in X. 2. Read the result: The tool detects whether it is an ISBN-10 or ISBN-13 and verifies the check digit. 3. Use the conversion: For a valid ISBN, the tool also shows the equivalent number in the other format. FAQ: Q: How are ISBN check digits calculated? A: ISBN-10 multiplies each digit by weights 10 down to 1 and is valid when the sum is divisible by 11 (a trailing X counts as 10). ISBN-13 uses alternating weights 1 and 3 and is valid when the sum is divisible by 10. Q: Does a valid ISBN mean the book exists? A: No. The check digit only confirms the number is internally consistent. It does not confirm that a real published title is assigned to that ISBN. Q: Why does an ISBN-10 sometimes end in X? A: ISBN-10 uses a modulo-11 check, so the check value can be 0 to 10. Because 10 needs a single character, it is written as the letter X. This only happens in the final position of an ISBN-10, never in an ISBN-13. Q: How do I convert ISBN-10 to ISBN-13? A: Drop the ISBN-10 check digit, prefix 978, then recompute the ISBN-13 check digit with the alternating 1-3 weights. The tool does this automatically and shows the equivalent number for any valid input. Q: What is the 978 or 979 prefix? A: ISBN-13 numbers begin with a GS1 prefix — 978 (the original "Bookland" range) or the newer 979. ISBN-10s map only to 978-prefixed ISBN-13s; 979 numbers have no ISBN-10 equivalent. Q: Is my input sent anywhere? A: No. Validation and conversion run entirely in your browser — privacy-first, your input never leaves the device. #### Ukraine INN Validator URL: https://geratools.com/ukraine-inn-validator Free Ukrainian tax number (RNOKPP / ІПН) validator. Decodes the embedded date of birth and gender and verifies the weighted check digit. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste the number: Enter the 10-digit RNOKPP / ІПН tax number. 2. Read the decoded fields: The tool shows the date of birth derived from the first five digits and the gender from the ninth digit. 3. Check the control digit: It confirms whether the final check digit matches the weighted formula. FAQ: Q: What does a Ukrainian tax number encode? A: The first five digits are the number of days since 31 December 1899, giving the date of birth. The ninth digit encodes gender (odd = male, even = female) and the tenth is a check digit. Q: Does the checksum prove the person exists? A: No. A valid check digit only shows the number is internally consistent. It does not confirm registration with the tax authority. Q: Is anything uploaded? A: No. All decoding and validation happen locally in your browser. Q: How long is a Ukrainian RNOKPP number? A: Exactly 10 digits. The official name is the registration number of the taxpayer's account card (РНОКПП); it is also widely called the ІПН (identification number). Q: How is the date of birth calculated from the number? A: The first five digits are a day count starting from 31 December 1899, where 00001 is 1 January 1900. The tool adds that many days to the base date to recover the full date of birth. Q: How is gender encoded in the RNOKPP? A: The ninth digit carries gender: an odd value means male and an even value means female. It is decoded directly without any lookup. Q: How is the check digit calculated? A: The first nine digits are multiplied by the fixed weights -1, 5, 7, 9, 4, 6, 10, 5, 7, summed, and the control is (sum mod 11) mod 10. That value must equal the tenth digit for the number to be valid. Q: Why does a valid number still get rejected by an institution? A: A passing checksum only proves the number is internally consistent. It does not confirm the number is registered with the State Tax Service (DPS), which an offline tool cannot check. #### Austria SVNR Validator URL: https://geratools.com/austria-svnr-validator Free Austrian SVNR (Sozialversicherungsnummer) validator. Decodes the embedded date of birth and verifies the weighted modulo-11 check digit. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste the SVNR: Enter the 10-digit Austrian social-security number. 2. Read the decoded fields: The tool shows the serial number and the date of birth from the last six digits. 3. Check the control digit: It confirms whether the fourth digit matches the weighted modulo-11 formula. FAQ: Q: How is an Austrian SVNR structured? A: It is ten digits: a three-digit serial, then a check digit, then the date of birth as DDMMYY. The check digit is computed with weights over the other nine digits modulo 11. Q: Why is a check digit of 10 never used? A: If the weighted formula produces 10, that serial is not issued and is re-allocated, so a valid SVNR never has a check digit of 10. Q: What does SVNR stand for? A: SVNR is short for Sozialversicherungsnummer, the Austrian social-security number used for health, pension and unemployment insurance. Q: Does a valid check digit mean the SVNR belongs to a real person? A: No. The check digit only confirms the number is internally consistent and the embedded date is plausible. It does not prove the number was issued or who holds it, and this tool contacts no register. Q: Is anything uploaded? A: No. All decoding and validation happen locally in your browser. Q: Is the date inside the SVNR always the real birth date? A: Usually, but not always. When all serials for a birth date are exhausted, or the birth date was unknown at registration, a number with a different date block can be assigned. Software should store date of birth separately and treat the decoded SVNR date as a plausibility check only. Q: Why should software store the SVNR as text rather than a number? A: Because the 3-digit serial can begin with zero. Storing the SVNR in a numeric field drops the leading zero, turning a valid 10-digit number into 9 digits that fail validation. Keep it as a string and validate the raw digits. #### Malaysia MyKad Validator URL: https://geratools.com/malaysia-mykad-validator Free Malaysia MyKad / NRIC structural validator. Checks every segment — date of birth, place-of-birth code, serial number and gender digit — and explains each pass or fail. Runs entirely in your browser; nothing is uploaded. How to use: 1. Enter or paste the 12-digit MyKad number: Type the number with or without dashes (both YYMMDD-PB-###G and 900101145567 are accepted). Dashes and spaces are stripped automatically. 2. Read the segment-by-segment verdict: Each of the four segments — date of birth, place-of-birth code, serial and gender digit — shows a green tick or red cross with a plain-English explanation of why it passed or failed. 3. Check the decoded fields: The decoded panel shows the inferred birth date, the state or territory mapped from the place-of-birth code, the sequential serial number and the gender encoded in the final digit. 4. Inspect the segment map: The colour-coded segment bar visually highlights which digits belong to each field so you can see at a glance where a problem is located. FAQ: Q: Does the Malaysian MyKad have a checksum digit? A: No. Unlike India Aadhaar (Verhoeff) or South Korea RRN (weighted modulus), the Malaysian NRIC format has no mathematical checksum. Validation is purely structural — date, place-of-birth code, serial range and format rules only. A structurally valid number cannot be confirmed as genuinely issued without access to the JPN database. Q: What does the format YYMMDD-PB-###G mean? A: YYMMDD is the date of birth (year, month, day — two digits each). PB is a two-digit place-of-birth code that maps to a Malaysian state or a foreign-born category. ### is a three-digit sequential serial issued within that date-and-state group. G is the gender digit: odd means male, even means female. Q: How accurate is the place-of-birth code check? A: The validator uses the full JPN-published code table. Codes 01-16 and 21-59 map to specific Malaysian states and federal territories; codes 60-82 are accepted as foreign-born or special-registration categories. A code outside all of these ranges is flagged as invalid. The tool cannot confirm a holder was born in a particular state — it only verifies the code is in the official set. Q: How does the validator handle the 2-digit birth year? A: The MyKad encodes only two year digits, so the full century must be inferred. This tool compares the two-digit value to the current year's last two digits. If the encoded value is less than or equal to the current two-digit year it assumes 21st century (2000s); otherwise it assumes 20th century (1900s). This matches the convention used by JPN at issuance but can only be correct for people born before the current year — an issue for IC numbers issued to infants born after the centennial rollover in 2000. Q: What makes a serial number invalid? A: The serial occupies digits 9-11 and represents a sequence number within each date-and-state group. The value 000 is reserved and never assigned. Any serial from 001 to 999 is valid. In practice high serial numbers (above 950) are rare but not prohibited by the format. Q: Can this tool tell if a MyKad number belongs to a real person? A: No. Without access to the JPN national registry there is no way to confirm a number was actually issued or corresponds to a living person. This tool confirms only that the number is structurally plausible — the right length, a real calendar date, a recognised place-of-birth code and a non-reserved serial. That is the maximum a public, offline validator can do for any NRIC without a checksum. #### North Macedonia EMBG Validator URL: https://geratools.com/north-macedonia-embg-validator Free online North Macedonia EMBG validator. Instantly checks the 13-digit Единствен матичен број на граѓанинот (Unique Master Citizen Number) checksum, decodes the encoded birth date, gender, and statistical region — all in your browser with no data uploaded. How to use: 1. Enter the 13-digit EMBG: Paste or type the full 13-digit number in the input field. Spaces and hyphens are stripped automatically, so formatted entries like 010199-041-001-2 also work. 2. Read the step-by-step result: The validator runs five checks in sequence: digit-only characters, length (exactly 13), a valid calendar date in positions 1-7, a recognised North Macedonia region code in positions 8-9, and the official weighted-sum checksum on digit 13. 3. Review the decoded information: On a pass, the tool surfaces the full birth date, birth year from the three-digit YYY encoding, the holders gender (odd BBB = male, even = female), and the statistical region associated with the registration. 4. Expand checksum workings: Click Show checksum workings to see the full pair-weighted arithmetic table — every digit pair, its weight, its contribution, the running sum, the mod-11 remainder, and the final 11-minus step that produces the check digit. FAQ: Q: What is the North Macedonia EMBG? A: The EMBG (Единствен матичен број на граѓанинот — Unique Master Citizen Number) is the 13-digit national identifier assigned to every citizen and permanent resident of North Macedonia. It was inherited from the Yugoslav JMBG system introduced in 1976 and encodes the holders birth date, statistical region of registration, a serial number within that group, and a checksum digit that allows instant structural verification. Q: What does each part of the EMBG encode? A: Positions 1-2 are the day of birth (01-31). Positions 3-4 are the month (01-12). Positions 5-7 are the last three digits of the birth year: values 500-999 decode to 1500-1999 (so 990 means 1990) and values 000-499 decode to 2000-2499 (so 005 means 2005). Positions 8-9 are the region code (41 = western, 42 = Skopje, 43 = eastern, 78 = born abroad). Positions 10-12 are the birth-order serial within the day-and-region group: odd means male, even means female. Position 13 is the checksum digit. Q: How is the EMBG checksum calculated? A: The algorithm pairs digit positions (1 with 7, 2 with 8, 3 with 9, 4 with 10, 5 with 11, 6 with 12) and multiplies each pair sum by a descending weight from 7 down to 2. The total is reduced modulo 11, then subtracted from 11. If the result is 11 the check digit is 0; if the result is 10 the number combination is invalid and the registry never issues it; otherwise the result itself (1-9) is the check digit stored in position 13. Q: What region codes are valid for a North Macedonia EMBG? A: North Macedonia uses four region codes in the two-digit RR field. Code 41 covers the western statistical region including Ohrid, Bitola, Gostivar, Tetovo and Debar. Code 42 covers the Skopje capital region. Code 43 covers the eastern and northeastern region including Stip, Kumanovo and Kocani. Code 78 is used for people born abroad who registered in North Macedonia. Numbers carrying other region codes are not issued by the Macedonian civil registry. Q: Can an EMBG pass every structural check and still be invalid? A: Yes. Structural validity confirms that the digits are self-consistent, the encoded date is a real calendar date, the region code is recognised, and the checksum matches. It does not confirm that the specific number was ever issued, that it belongs to the person presenting it, or that it is currently active. Only the Ministry of Interior of North Macedonia can confirm issuance status. Q: Is my data kept private? A: Completely. The validator is a static page and all computation happens inside your browser using JavaScript. No number, partial or full, is ever sent to a server or logged anywhere. #### Turkey TC Kimlik No Validator URL: https://geratools.com/turkey-tc-kimlik-validator Free Turkish T.C. Kimlik No validator. Checks the leading-digit rule and both official check-digit formulas entirely in your browser — shows the full arithmetic breakdown so you can pinpoint any typo. Nothing is uploaded. How to use: 1. Enter the number: Type or paste the 11-digit Turkish T.C. Kimlik No into the field. Spaces are stripped automatically. 2. Read the instant verdict: The tool checks the leading-digit rule and both official check-digit formulas as you type. 3. Inspect the arithmetic breakdown: Every intermediate value — the odd-position sum, even-position sum, and the modulo steps — is shown in a table so you can see exactly where a typo broke validation. 4. Copy the number: Use the Copy button to put the clean 11-digit string on your clipboard. FAQ: Q: How is a Turkish TC Kimlik No validated? A: Three rules must all hold. First, the leading digit must not be zero. Second, the tenth digit equals ((sum of the 1st, 3rd, 5th, 7th and 9th digits multiplied by 7) minus the sum of the 2nd, 4th, 6th and 8th digits), taken modulo 10. Third, the eleventh digit equals the sum of the first ten digits, taken modulo 10. Q: Does the TC Kimlik No encode a date of birth or gender? A: No. Unlike many national ID numbers — such as the Polish PESEL, South African ID, or Chinese Resident ID — the Turkish T.C. Kimlik No does not encode a birth date, sex, or region by any publicly released specification. It is a sequentially assigned number protected by two arithmetic check digits only. Q: Is my ID number uploaded anywhere? A: No. The validator is implemented entirely in client-side JavaScript that runs in your browser tab. Your number is never sent to any server, never logged, and never stored — the page works even offline after it has loaded. Q: How many digits is a TC Kimlik No? A: Exactly 11 decimal digits. A number with any other length is structurally invalid. The first nine digits are the core identity sequence, the tenth is the first check digit, and the eleventh is the second check digit. Q: Why can the first digit not be zero? A: A leading zero would reduce the effective numeric length to ten digits, creating ambiguity and making the number look like a ten-digit string. The specification therefore forbids it — every valid T.C. Kimlik No begins with the digits 1 through 9. Q: Does passing the checksum confirm the person is registered in MERNIS? A: No. A passing result only means the number is internally self-consistent and free of common transcription errors. The only authoritative confirmation that a number belongs to a real, living, registered person is a query to the Turkish Ministry of Interior MERNIS civil register, which requires proper legal authorisation. ### SEO & Web #### Twitter Card Preview URL: https://geratools.com/twitter-card-preview Free Twitter card preview tool. See how your link will look as a summary or large-image card on X (Twitter), and copy ready-made twitter meta tags. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a card type: Pick summary_large_image for a wide image card or summary for a small thumbnail card. 2. Enter your content: Fill in the title, description, URL and image for the page you are sharing. 3. Copy the tags: Paste the generated twitter meta tags into the head of your page. FAQ: Q: What is the difference between summary and summary_large_image? A: The summary card shows a small square thumbnail beside the text. summary_large_image shows a full-width image above the text, ideal for visual content. Use a roughly 1200 by 628 image for the large card. Q: Do I still need Open Graph tags? A: X reads Twitter card tags first but falls back to Open Graph tags when they are missing. Adding both gives the most reliable preview across all platforms. Q: Is my data sent anywhere? A: No. The card preview and tag generation happen entirely in your browser. Nothing you type is uploaded. Q: What image size should I use for a large image card? A: A roughly 1200 by 628 pixel image at a 1.91:1 ratio works well for summary_large_image. Smaller images may be cropped or shown as a summary card instead. Q: How long should the title and description be? A: Keep the title under about 70 characters and the description under about 200, since X truncates longer text in the feed. The preview reflects how it will appear. Q: Which meta tags does it generate? A: It outputs twitter:card, twitter:title, twitter:description, twitter:url and twitter:image tags, ready to paste into the head of your page. Q: Will the live card match this preview exactly? A: It is a close approximation of X's layout. The actual render can vary slightly by client and over time, and X re-crawls your page, so confirm with X's own validator before launch. ### Config & Code Scaffolding #### Architecture Decision Record (ADR) Builder URL: https://geratools.com/architecture-decision-record-builder Create an Architecture Decision Record in the Michael Nygard format with Title, Status, Context, Decision, Consequences, and alternatives considered. Numbered and exported as clean Markdown for your adr/ folder. How to use: 1. Set the title and status: Give the decision a short imperative title and choose its lifecycle status such as Proposed or Accepted. 2. Capture context and decision: Describe the forces at play, then state the decision in a single clear sentence with its rationale. 3. List consequences and alternatives: Record the positive and negative consequences and the options you rejected, then copy the Markdown. FAQ: Q: What is an Architecture Decision Record? A: An ADR is a short document that captures one significant architecture decision, the context that forced it, and its consequences. Recording decisions this way gives future engineers the reasoning behind the system, not just the outcome. Q: What is the Nygard ADR format? A: It is the original lightweight template by Michael Nygard with five core sections: Title, Status, Context, Decision, and Consequences. This builder follows that format and adds an optional Alternatives section for the options you rejected. Q: How should I name the file? A: Convention is a zero-padded number plus a slug, like 0007-use-event-sourcing.md, stored in a docs/adr folder. The builder shows you the suggested filename based on the record number and title. Q: When should a status be Superseded? A: Mark an ADR as Superseded when a later record reverses or replaces its decision, and reference the new ADR number. Accepted records are never edited or deleted, only superseded, so the history stays intact. Q: Is my decision data uploaded anywhere? A: No. The builder runs entirely in your browser, so your architecture decisions stay private and are never sent to a server. #### CODEOWNERS File Builder URL: https://geratools.com/codeowners-builder Map file path patterns to GitHub users and teams and generate a valid CODEOWNERS file that auto-assigns the right reviewers on every pull request, with validation for the @owner syntax, last-match-wins ordering, and a default catch-all rule. How to use: 1. Add ownership rules: For each rule enter a file path pattern such as /src/api/ and one or more owners like @alice or @org/backend-team. 2. Set a default owner: Optionally add a top-level catch-all owner with the * pattern so every unmatched file still has a reviewer. 3. Copy the CODEOWNERS file: Copy the output and save it to .github/CODEOWNERS, CODEOWNERS, or docs/CODEOWNERS in your repository. FAQ: Q: Where does the CODEOWNERS file go? A: GitHub looks for it in the repository root, in the .github directory, or in the docs directory. Most teams use .github/CODEOWNERS. Only one location is used, with .github taking priority if several exist. Q: How does matching work when patterns overlap? A: CODEOWNERS uses last-match-wins. GitHub reads the file top to bottom and the final matching line decides the owners for a file, so place broad catch-all rules first and the most specific rules last. Q: What owner formats are valid? A: Owners must be a GitHub username like @alice, a team like @org/team-name, or an email address that belongs to a repository member. Plain names without an @ or a team without the org prefix are invalid and silently ignored. Q: Do code owners become required reviewers? A: Only if you enable the require review from Code Owners branch protection rule. Without that setting CODEOWNERS still auto-requests reviews from the matching owners but does not block merging. Q: Is anything uploaded by this tool? A: No. The CODEOWNERS file is built entirely in your browser from the rules you enter, so you can safely use it for private repositories without sending data anywhere. #### DMARC Record Builder & Policy Explainer URL: https://geratools.com/dmarc-record-builder Build a valid DMARC TXT record from a guided form — policy, subdomain policy, reporting addresses, enforcement percentage, and SPF/DKIM alignment — with a plain-English explanation of every tag. Validates report emails and warns before risky enforcement. Fully offline. How to use: 1. Pick a policy: Start with p=none to monitor without affecting delivery, then move to quarantine and finally reject once your SPF and DKIM are aligned and passing. 2. Add a reporting address: Enter an rua address to receive daily aggregate reports. These show who is sending mail as your domain — the data you need before enforcing. 3. Copy the record and hostname: Publish the TXT value at _dmarc.yourdomain. Use the per-tag explanations to understand exactly what you are turning on. FAQ: Q: What is the difference between p=none, quarantine, and reject? A: p=none takes no action and only sends reports — it is the monitoring stage. p=quarantine tells receivers to treat failing mail as suspicious, usually routing it to spam. p=reject blocks failing mail outright at the SMTP layer, the strongest protection. The standard path is none then quarantine then reject. Q: Where is the DMARC record published? A: As a TXT record at the special hostname _dmarc.yourdomain (for example _dmarc.example.com), not at the domain apex. There is exactly one DMARC record per domain, and subdomains inherit it unless you set a separate sp policy. Q: What does DMARC alignment mean? A: Alignment requires that the domain authenticated by SPF or DKIM matches the visible From domain. Relaxed alignment (the default) allows subdomains to match the organisational domain; strict alignment requires an exact match. DMARC only passes when at least one of SPF or DKIM both passes and aligns. Q: Should I set the ruf (forensic) tag? A: It is optional and increasingly unsupported. Forensic reports contain per-message failure details that can include recipient data, so many providers stopped sending them for privacy reasons. Aggregate reports (rua) are the ones you actually rely on for visibility. Q: Why use the pct tag? A: pct applies your policy to only a percentage of failing mail, letting you ramp enforcement gradually — for example pct=25 with p=quarantine quarantines a quarter of failures while the rest are merely monitored. It is a safety valve while you confirm legitimate mail is aligned. #### Dockerfile Builder for React Static Site (Nginx) URL: https://geratools.com/dockerfile-builder-react-static Generate a multi-stage Dockerfile that builds a React, Vite, or Create React App project with Node and serves the static output through a minimal Nginx image, plus a matching nginx.conf with SPA routing. Runs entirely in your browser. How to use: 1. Configure the build: Choose your Node version, package manager, build script name, and the output directory your bundler produces. 2. Set SPA routing: Leave SPA history fallback on for client-side routed apps so deep links resolve to index.html. 3. Copy both files: Copy the Dockerfile and the generated nginx.conf into your project root, then run docker build. FAQ: Q: Why serve a React app with Nginx instead of Node? A: A built React app is just static HTML, CSS, and JavaScript — there is no server-side rendering to do. Nginx serves static files faster and with a far smaller memory footprint than a Node process, and the runtime image contains no Node, no npm, and no source code. Q: What does the SPA history fallback do? A: Client-side routers like React Router handle paths in the browser, but a direct request to /dashboard would otherwise return a 404 from Nginx. The fallback rewrites unmatched paths to index.html so the router can take over. Disable it for purely static multi-page sites. Q: Why copy the lockfile before the source? A: Copying package.json and the lockfile, then running the install, before copying the rest of your source lets Docker cache the dependency layer. Editing application code no longer re-runs the install, so rebuilds are much faster. Q: Which output directory should I choose? A: Vite outputs to dist, Create React App outputs to build, and a Next.js static export outputs to out. Pick the one your build script produces — the runtime stage copies that folder into the Nginx web root. Q: How small is the final image? A: Because the runtime stage is nginx:alpine plus your static assets, the image is typically only a few megabytes larger than the Nginx base — usually under 25 MB — compared with hundreds of megabytes if you shipped the whole Node toolchain. #### Dockerfile Linter URL: https://geratools.com/dockerfile-linter Free in-browser Dockerfile linter implementing hadolint rules. Paste a Dockerfile and instantly flag unpinned base images, apt-get without --no-install-recommends, ADD vs COPY misuse, running as root, missing HEALTHCHECK, shell-form CMD and more. Nothing is uploaded. How to use: 1. Paste your Dockerfile: Copy your Dockerfile and paste it into the box. The linter understands multi-line RUN commands joined with backslashes and ignores comments. 2. Review the findings: Each issue shows a rule code, a severity (error, warning or info), the affected line, and a plain-English explanation of why it matters. 3. Fix and re-check: Apply the suggested change, paste the updated Dockerfile, and confirm the warning disappears. The list re-runs as you type. FAQ: Q: Which rules does this linter check? A: It ports the most actionable hadolint rules: unpinned or latest base images (DL3006/DL3007), apt-get and apk hygiene (DL3009/DL3015/DL3019), using cd instead of WORKDIR (DL3003), ADD vs COPY (DL3020), running as root (DL3002), missing HEALTHCHECK (DL3057), shell-form CMD/ENTRYPOINT (DL3025), sudo (DL3004) and unguarded download pipes (DL4006). Q: Does my Dockerfile leave my browser? A: No. The linter is pure JavaScript that runs locally. Your Dockerfile, including any private base-image registry names or build arguments, is never uploaded or logged. Q: Why does it warn about running as root? A: By default a container process runs as root, which means a container escape grants root on the host namespace. Adding a non-root USER before the final CMD or ENTRYPOINT follows the principle of least privilege and is a baseline hardening step. Q: What is wrong with ADD for local files? A: ADD has implicit behaviour — it auto-extracts local tar archives and can fetch remote URLs without verification. COPY does exactly one predictable thing: copy files into the image. Use COPY for local files and reserve ADD for the rare case where you genuinely want tar extraction. Q: Can it replace hadolint in CI? A: It is a fast preview that catches the same common mistakes, but it does not implement every hadolint rule or its shellcheck integration. Keep hadolint in your CI pipeline for full coverage; use this tool for quick interactive checks while you edit. #### GitHub Bug Report Issue Template Builder URL: https://geratools.com/github-issue-template-bug Creates a structured GitHub issue form (bug_report.yml) with Steps to Reproduce, Expected and Actual Behavior, Environment, and Screenshots fields using the modern YAML issue-form schema, ready to drop into .github/ISSUE_TEMPLATE. How to use: 1. Set the form details: Enter the template name, the title prefix, default labels, and any assignees that should be attached to new bug reports automatically. 2. Toggle fields: Choose which sections to include — reproduction steps, expected behavior, actual behavior, environment, version, and screenshots. 3. Save the file: Copy the YAML into .github/ISSUE_TEMPLATE/bug_report.yml in your repository. GitHub renders it as a guided issue form. FAQ: Q: Where does this file go in my repo? A: Place it at .github/ISSUE_TEMPLATE/bug_report.yml. GitHub automatically detects files in that folder and offers them as choices when a user clicks New Issue. Q: What is the difference between an issue form and a markdown template? A: A YAML issue form renders structured input fields with validation, while an older markdown template is just pre-filled text. Forms produce cleaner, more consistent reports because reporters fill labelled boxes instead of editing prose. Q: How do required fields work? A: Each field can set validations.required to true. GitHub blocks submission until those fields are filled, which guarantees you always get reproduction steps and a description before a bug lands in your queue. Q: Can I auto-apply labels and assignees? A: Yes. The labels key attaches one or more labels to every issue created from the form, and the assignees key auto-assigns people. This tool adds both to the top-level form metadata. Q: What field types are used? A: The form uses textarea blocks for free-form sections like steps and behavior, an input for the version, and a dropdown is available for environment. Markdown blocks add instructions that are not submitted with the issue. #### .gitignore Builder for .NET / C# URL: https://geratools.com/gitignore-builder-dotnet Build a .gitignore for .NET and C# projects. Covers bin/, obj/, .vs/, *.user, NuGet packages, publish output and test results for Visual Studio and Rider — copy or download in your browser. How to use: 1. Pick your sections: Tick the parts of your .NET project to ignore, such as bin/obj output, Visual Studio files and publish output. 2. Review the file: The combined .gitignore is assembled instantly with labelled section headers. 3. Copy or download: Copy the text or download a ready-to-commit .gitignore file for your repository root. FAQ: Q: Why ignore the bin/ and obj/ folders? A: bin/ holds compiled assemblies and obj/ holds intermediate build files; both are regenerated by MSBuild from your source on every build. The patterns are case-insensitive so they catch Bin, BIN and Debug/Release variants too. Q: Should I ignore *.user and .vs/ files? A: Yes. The .vs/ folder and *.user files store per-developer Visual Studio state like window layout and last-opened files. They cause noisy diffs and should stay local to each machine. Q: Do I commit the packages folder for NuGet? A: Modern PackageReference projects restore NuGet packages on build, so the packages/ folder is ignored and not committed. Only legacy packages.config projects might commit it, which is no longer recommended. Q: Why ignore publish output? A: The publish/ folder and *.pubxml.user files contain deployment-specific output and credentials generated by dotnet publish or Visual Studio. They are derived artifacts and may hold secrets, so they belong in .gitignore. Q: Is anything uploaded to a server? A: No. Every template is built into the page and the file is assembled in your browser, so nothing about your project leaves your machine. #### ISO-8601 Date-Time Builder URL: https://geratools.com/iso8601-builder Free ISO-8601 date-time builder. Enter year, month, day, hour, minute, second and UTC offset to assemble a well-formed ISO-8601 timestamp, with validation for each field. Runs entirely in your browser. How to use: 1. Fill in the date and time fields: Enter year, month, day, hour, minute and second. Out-of-range values are flagged so you can correct them. 2. Choose the timezone offset: Set the UTC offset (such as +00:00 for UTC or -05:00 for US Eastern), or select Z for Zulu/UTC. 3. Copy the result: The tool assembles a valid ISO-8601 string, confirms it parses, and lets you copy it in one click. FAQ: Q: What does a valid ISO-8601 date-time look like? A: It follows the pattern YYYY-MM-DDThh:mm:ss followed by a timezone designator, for example 2026-06-06T14:30:00+01:00 or 2026-06-06T13:30:00Z. The T separates the date from the time. Q: What is the difference between Z and +00:00? A: Both mean UTC. Z (Zulu time) is shorthand for a zero UTC offset and is equivalent to writing +00:00. ISO-8601 and RFC-3339 accept either form. Q: How are months and days validated? A: The builder checks that the month is 1 to 12 and that the day is valid for the chosen month and year, including 29 February only in leap years, so it will not produce an impossible date like 2025-02-30. Q: Can I include fractional seconds? A: This builder produces whole-second precision. If you need fractional seconds you can append them manually after the seconds field, for example .500, before the offset. Q: Is my date sent to a server? A: No. The string is assembled and validated entirely in your browser. Nothing is uploaded. #### Kubernetes ConfigMap Builder URL: https://geratools.com/kubernetes-configmap-builder Build a Kubernetes ConfigMap YAML with simple key-value pairs and multi-line file entries for mounting as volumes or env vars. Handles YAML quoting and block scalars automatically. How to use: 1. Name the ConfigMap: Set the ConfigMap name and target namespace. These become the metadata fields of the manifest. 2. Add configuration data: Add simple KEY=VALUE pairs for environment variables, and file entries for whole config files you want mounted as volumes. 3. Copy the YAML: Copy the generated manifest and apply it with kubectl apply -f, then reference it from a Deployment via envFrom or a volume. FAQ: Q: What is a Kubernetes ConfigMap? A: A ConfigMap is an API object that stores non-confidential configuration as key-value pairs. Pods consume it as environment variables, command-line arguments, or files mounted from a volume, keeping configuration separate from container images. Q: When should I use a ConfigMap instead of a Secret? A: Use a ConfigMap for non-sensitive data like log levels, feature flags, hostnames, and config files. Use a Secret for passwords, tokens, and keys. ConfigMap data is stored in plaintext in etcd and is not meant to hold credentials. Q: How do file entries differ from key-value pairs? A: Key-value pairs are single-line scalars, ideal for env vars. File entries are emitted as YAML block scalars so the full multi-line content is preserved. When mounted as a volume, each file entry becomes a file named after its key. Q: What does the immutable flag do? A: Setting immutable: true prevents the ConfigMap from being changed after creation. This protects against accidental updates and lets the kubelet skip watching it, reducing API server load. To change it you must delete and recreate it. Q: How do I mount this ConfigMap into a pod? A: Reference it in a Deployment under volumes as a configMap source, then mount that volume into the container, or use envFrom with configMapRef to load all keys as environment variables. #### llms.txt File Builder URL: https://geratools.com/llms-txt-builder Creates a properly formatted llms.txt file with site description, key pages, content areas, and AI-readable context about your product, following the llms.txt standard. Add links with titles and notes, then copy. How to use: 1. Enter your site title and summary: Add your site or product name and a one-line summary that tells an AI model what you offer. 2. Add link sections: Group your most important pages under headings like Docs or Guides, each with a URL, title, and optional note. 3. Copy the llms.txt: Copy the generated file and host it at the root of your domain as /llms.txt with a text/plain content type. FAQ: Q: What is llms.txt? A: llms.txt is a proposed standard for a Markdown file at the root of a website that gives large language models a curated, machine-readable map of your most important content. It helps AI tools find and cite the right pages instead of guessing from raw HTML. Q: Where do I put the llms.txt file? A: Host it at the root of your domain so it resolves at https://yoursite.com/llms.txt, and serve it with a text/plain content type. Many sites also publish an llms-full.txt with the full text content for deeper context. Q: What is the difference between llms.txt and robots.txt? A: robots.txt tells crawlers which paths they may or may not fetch, while llms.txt curates and describes your best content for AI models to read and cite. They serve different goals and you can publish both. Q: What format does llms.txt use? A: It uses Markdown. The file starts with an H1 title, an optional blockquote summary, then H2 sections containing bullet lists of links written as Markdown link syntax with an optional note after a colon. Q: Is my site data sent anywhere? A: No. The builder assembles the llms.txt entirely in your browser from the fields you fill in. Nothing is uploaded, so you can draft the file for an unreleased site safely. #### Penetration Test Scope Document Builder URL: https://geratools.com/pen-test-scope-document-builder Builds a penetration test scope and rules-of-engagement document with in-scope targets, IP ranges, permitted test types, explicit out-of-scope systems, a testing window, emergency contacts, reporting requirements, and an authorization sign-off block. How to use: 1. Name the parties and targets: Enter the client, the testing vendor, and the in-scope targets and IP ranges that may be tested. 2. Set rules and exclusions: Select the permitted test types, list out-of-scope systems explicitly, and define the testing window and emergency contact. 3. Copy the document: Add your reporting requirements and copy the assembled scope document, including the authorization sign-off block, for both parties to sign. FAQ: Q: What is a pen test scope document? A: It is the written agreement that defines exactly what a penetration tester may and may not touch, when, and how. It protects both the client and the tester by removing ambiguity about authorization and boundaries. Q: Why list out-of-scope systems explicitly? A: Naming systems that must not be tested — third-party hosted services, production databases, anything fragile — prevents accidental outages and legal exposure. An explicit exclusion list is clearer and safer than assuming testers will infer boundaries. Q: What are rules of engagement? A: Rules of engagement are the operating constraints for the test: no real-data exfiltration, no destructive actions, identifiable testing traffic, and an immediate-stop rule if a live outage risk appears. They keep an aggressive test from causing real harm. Q: Why include an emergency contact and testing window? A: A defined window tells operations and monitoring teams when alerts are expected from testing, and the emergency contact gives the tester someone to reach instantly if something goes wrong. Together they prevent a finding from becoming an incident. Q: Is the authorization block legally important? A: Yes. Penetration testing without written authorization can constitute unauthorized access. The signed authorization block establishes that the client explicitly permitted the listed testing, which is the legal basis for the engagement. #### Python requirements.txt Builder URL: https://geratools.com/python-requirements-txt-builder Pick a project type (web API, data science, ML, CLI, scraping) and get a version-pinned requirements.txt with the core libraries, exact or compatible-release pins, and optional dev/test dependencies. How to use: 1. Choose a project type: Select web API, data science, machine learning, CLI or scraping to load the matching set of core libraries. 2. Pick a pin style: Choose exact pins (==) for fully reproducible installs or compatible-release pins (~=) to allow safe patch updates. 3. Copy or download: Copy the list or download requirements.txt, then install with pip install -r requirements.txt. FAQ: Q: What is the difference between == and ~= pins? A: An exact pin like fastapi==0.115.6 locks the version precisely for reproducible builds. A compatible-release pin like fastapi~=0.115.6 allows later patch versions (0.115.x) but not 0.116, balancing reproducibility with automatic bug fixes. Q: Should dev tools go in the same file? A: Many projects keep test and lint tools (pytest, ruff, mypy) in a separate requirements-dev.txt so production installs stay lean. This builder can include them with a comment showing where to split them out. Q: Are the pinned versions guaranteed current? A: The versions reflect recent stable releases at build time, not a live feed. Treat them as a sensible starting point, then run pip list --outdated and re-pin before relying on the file long term. Q: How do I make installs fully reproducible? A: Exact pins fix direct dependencies, but transitive dependencies can still drift. For full reproducibility, generate a lock file with pip-tools (pip-compile) or use a tool like uv or Poetry that records the entire resolved tree. Q: Why pin versions at all? A: Without pins, pip installs the newest compatible release each time, so a deploy weeks apart can pull different code and break in production. Pinning makes the same versions install everywhere, which is essential for CI and Docker images. #### sonar-project.properties Builder URL: https://geratools.com/sonarqube-properties-builder Build a sonar-project.properties file with project key, name, version, source and test directories, exclusions, server URL, source encoding, and language-specific coverage report paths for SonarQube or SonarCloud. How to use: 1. Set project identity: Enter a unique project key, a display name, and a version. The key must be unique on your SonarQube server or SonarCloud organization. 2. Point to sources and coverage: List source and test directories, add exclusion globs, and choose your language so the right coverage report property is emitted. 3. Copy into your repo: Copy the generated file into the repository root as sonar-project.properties so the scanner picks it up automatically. FAQ: Q: Where does sonar-project.properties live? A: Place it in the root of the repository you scan, next to package.json. The SonarScanner CLI reads it from the working directory automatically, so no extra flags are needed for the listed keys. Q: Do I need the organization key? A: Only for SonarCloud, where sonar.organization is required. For a self-hosted SonarQube server you leave it blank — the project key and host URL are enough. Q: How does coverage import work? A: SonarQube does not run your tests; it imports a coverage report your CI already produced. For JS/TS that is an LCOV file, for Python a coverage.xml, and for Java a JaCoCo XML report. The builder writes the matching property for your language. Q: What format do exclusions use? A: Comma-separated Ant-style globs relative to the project base. For example **/node_modules/** or **/*.spec.ts. Files matching sonar.exclusions are skipped during analysis. Q: Can I keep secrets out of this file? A: Yes. Never put the authentication token in sonar-project.properties. Pass it at scan time with the SONAR_TOKEN environment variable or the -Dsonar.login flag instead. ### Converters & Encoders #### A1 ↔ R1C1 Notation Converter URL: https://geratools.com/a1-to-r1c1-converter Convert spreadsheet cell references between A1 notation such as B3 and R1C1 notation such as R3C2. Handles single cells and ranges using the same bijective base-26 column math as Excel. How to use: 1. Choose direction: Pick A1 to R1C1 if you have a label like B3, or R1C1 to A1 if you have a reference like R3C2. 2. Enter the reference: Type a single cell or a range using a colon, such as A1:C10. Input is case-insensitive. 3. Read the converted reference: The tool shows the equivalent reference in the other notation, with the parsed row and column shown for verification. FAQ: Q: What is R1C1 notation? A: R1C1 notation identifies a cell by its row and column numbers, written as R then the row, C then the column. So R3C2 means row 3, column 2, which is the same cell as B3 in A1 notation. Q: How does A1 notation differ from R1C1? A: A1 notation labels the column with letters and the row with a number, like B3. R1C1 uses numbers for both axes. R1C1 makes relative offsets and formula patterns easier to read. Q: How are the column letters and numbers related? A: Columns use bijective base-26: A=1, B=2, up to Z=26, then AA=27. The converter applies this exact mapping so B becomes column 2 and AA becomes column 27. Q: Can it convert cell ranges? A: Yes. Enter a range with a colon such as A1:C10 and both endpoints are converted, producing R1C1:R10C3. Single-cell references work the same way without a colon. Q: Does it support relative R1C1 offsets like RC[-1]? A: This converter handles absolute references where the row and column are explicit numbers. Relative bracketed offsets such as R[1]C[-2] depend on the active cell and are outside its scope. #### Arbitrary Base Converter URL: https://geratools.com/arbitrary-base-converter Convert integers between any two numeral bases from 2 to 36 using digits 0-9 and A-Z. Exact big-integer arithmetic handles huge numbers with no rounding, plus a decimal cross-check. Runs entirely in your browser. How to use: 1. Enter your number: Type the integer you want to convert in its current notation. You can use digits 0-9 and letters A-Z, and an optional leading minus sign. 2. Pick the source and target bases: Choose the base your number is written in under "From base", then choose the base you want the result in under "To base". Both range from 2 to 36. 3. Read the converted value: The result appears immediately in the target base, along with the plain decimal value so you can sanity-check the conversion. FAQ: Q: What is a numeral base? A: A base (or radix) is the number of distinct digits a positional number system uses. Base 10 (decimal) uses 0-9; base 2 (binary) uses 0 and 1; base 16 (hexadecimal) uses 0-9 then A-F. Q: Why does the converter stop at base 36? A: Base 36 is the largest base expressible with the standard ten digits 0-9 plus the 26 letters A-Z, giving 36 distinct single-character digits. Higher bases would need additional symbols with no universal convention. Q: How are letters used as digits? A: After the digits 0-9, letters take over: A is 10, B is 11, and so on up to Z which is 35. Input is case-insensitive, so 'ff' and 'FF' both mean 255 in hexadecimal. Q: Will very large numbers lose precision? A: No. The converter uses exact big-integer arithmetic rather than floating-point, so a 200-digit input converts to any base with no rounding error. Q: Can it convert negative numbers or fractions? A: It handles negative integers via a leading minus sign. It does not convert fractional values; for fixed-point or floating-point bit layouts, use the dedicated fixed-point or IEEE-754 tools. #### ASCII / Unicode Code to Character URL: https://geratools.com/ascii-code-to-char Convert one or many decimal or hexadecimal code points into the characters they represent. Decodes plain ASCII and full Unicode including emoji, with input separated by spaces, commas, or newlines, all in your browser. How to use: 1. Choose the base: Select Decimal or Hexadecimal to match how your code points are written (0x-prefixed tokens are always read as hex). 2. Enter the codes: Type or paste code points separated by spaces, commas, or newlines. 3. Copy the text: Read the decoded string and copy it with one click. FAQ: Q: What separators can I use between codes? A: Spaces, commas, and newlines all work, and you can mix them. For example "72, 105 33" and "72 105 33" both decode to Hi!. Q: How do I enter hexadecimal codes? A: Either switch the base selector to Hexadecimal, or prefix individual tokens with 0x. In hex mode, 48 is read as 0x48 (the letter H); in decimal mode, 48 is the digit 0. Q: Can it decode emoji and other non-ASCII characters? A: Yes. It uses String.fromCodePoint, so any valid Unicode code point works. For example 0x1F600 decodes to 😀 and 233 decodes to é. Q: Why are some numbers rejected? A: Code points must be in the range 0 to 0x10FFFF, and the surrogate range 0xD800 to 0xDFFF is rejected because those values are not standalone characters in Unicode. Out-of-range or malformed tokens are reported as errors. Q: Is this the same as ASCII for small numbers? A: Yes. For code points 0 to 127 the result is exactly the ASCII character, so 65 always gives A. Larger values use the broader Unicode mapping. #### Audio Sample Rate Converter URL: https://geratools.com/audio-sample-rate-converter Decode an MP3, WAV, or OGG and resample it to 8000–96000 Hz using an OfflineAudioContext at the target rate, then download a 16-bit PCM WAV. Fully client-side — your audio file never leaves the browser. How to use: 1. Pick a target rate: Choose the sample rate you need — 44100 Hz for CD, 48000 Hz for video, or a lower rate for smaller files. 2. Load your audio: Select an MP3, WAV, OGG, or M4A. It is decoded and resampled with the Web Audio API in your browser. 3. Download the WAV: The resampled audio is encoded as a 16-bit PCM WAV that you can download and use anywhere. FAQ: Q: How does the resampling work? A: The file is decoded to PCM, then re-rendered through an OfflineAudioContext created at the target sample rate. The browser's built-in resampler handles the interpolation, and the result is encoded to a standard WAV. Q: Why is the output always a WAV? A: WAV is uncompressed PCM that every browser can write reliably, so there is no quality loss from re-encoding to a lossy format. You can convert the WAV to MP3 or AAC afterward in your editor if you need a smaller file. Q: Will downsampling lose quality? A: Lowering the sample rate reduces the highest frequency the file can represent (the Nyquist limit is half the rate). The resampler low-pass filters to prevent aliasing, but very low rates like 8000 Hz will sound noticeably duller. Q: Is my file uploaded? A: No. Decoding, resampling, and WAV encoding all happen in your browser. Nothing is sent to a server, so the converter works offline and keeps your audio private. Q: Does it change the duration or pitch? A: No. Resampling changes only how many samples per second represent the audio; the playback duration and pitch stay the same. #### Base122 Encoder/Decoder URL: https://geratools.com/base122-encode Free Base122 encoder and decoder that packs binary data into minimal UTF-8 bytes using 7-bit chunks. Denser than Base64 for embedding in HTML or JavaScript. 100% client-side, nothing is uploaded. How to use: 1. Pick encode or decode: Choose whether you are turning text into Base122 or reading a Base122 string back into the original text. 2. Paste your input: Type or paste UTF-8 text to encode, or a Base122 string to decode, into the text box. 3. Copy the result: The result updates live below. Use the copy button to grab it for your HTML or JavaScript source. FAQ: Q: How is Base122 denser than Base64? A: Base64 maps every 6 input bits to one 8-bit ASCII character, a 33% size increase. Base122 reads 7 bits at a time and emits a single UTF-8 byte for almost all of them, so the encoded payload is typically only about 14% larger than the raw bytes. Q: Why does Base122 escape certain values? A: Six byte values are unsafe inside HTML and JavaScript string literals: null, newline, carriage return, double quote, ampersand and backslash. Base122 detects those six 7-bit values and emits a compact two-byte escape sequence so the output stays a valid, embeddable string. Q: Is Base122 a standard? A: No. Base122 is an experimental encoding designed by Kevin Albertson to shrink binary embedded in web pages. It is not an IETF standard, so use it where you control both the encoder and decoder rather than for interchange with arbitrary tools. Q: Can I decode any Base122 string here? A: Yes, as long as it was produced by a compatible Base122 implementation. This tool follows the original 7-bit chunking and two-byte escape scheme, so round-trips through this page are exact. Q: Is my data sent to a server? A: No. All bit packing, escaping and decoding happen locally in your browser with the built-in TextEncoder and TextDecoder. Nothing leaves your device. #### Base91 Encoder/Decoder URL: https://geratools.com/base91-encoder Encode and decode text or binary data with basE91, the printable-ASCII scheme that is more compact than Base64. Runs entirely in your browser using the canonical Joachim Henke 91-character alphabet. Free and instant. How to use: 1. Choose a mode: Select Encode to turn plain text into basE91, or Decode to recover the original text from a basE91 string. 2. Paste your data: Type or paste the text in the input box. Encoding works on the UTF-8 bytes of whatever you enter. 3. Copy the result: The converted output appears instantly below; click Copy to put it on your clipboard. FAQ: Q: How is Base91 different from Base64? A: Base64 maps 3 bytes to 4 characters, a 33% size increase. basE91 squeezes about 13 bits into 2 characters, so the overhead drops to roughly 23%. It uses 91 printable ASCII characters instead of 64. Q: Which characters does the alphabet use? A: It uses 91 printable ASCII characters and deliberately excludes the dash, backslash and apostrophe-style quoting hazards, making the output safe to embed in source code and many text formats. Q: Is Base91 a standard like Base64? A: It is a de-facto standard defined by Joachim Henke's reference implementation rather than an IETF RFC. This tool follows that canonical bit-packing algorithm so output is interoperable with other basE91 libraries. Q: Can I encode binary files? A: This in-browser tool operates on text input encoded as UTF-8 bytes. The underlying algorithm handles arbitrary bytes, but the input box is text, so use it for strings and UTF-8 payloads. Q: Why does my decoded output look garbled? A: Decoding produces raw bytes. If those bytes are not valid UTF-8 text — for example, they came from a non-text binary — the tool cannot render them as readable characters and reports an error. #### Baudot / ITA-2 Encoder URL: https://geratools.com/baudot-encoder Free Baudot ITA-2 encoder and decoder. Convert text to the 5-bit Baudot-Murray (ITA-2) code used by teleprinters and TTY, with automatic LTRS and FIGS shift handling, and decode 5-bit groups back to text. Runs entirely in your browser. How to use: 1. Choose encode or decode: Encode turns text into 5-bit ITA-2 groups; Decode turns space-separated 5-bit groups back into text. 2. Enter your message: When encoding, type letters, digits, and supported punctuation. When decoding, paste 5-bit groups separated by spaces, such as 11010 00001. 3. Read the result: The encoder inserts LTRS and FIGS shift codes automatically and lists any characters that have no ITA-2 equivalent. Click Copy to reuse the output. FAQ: Q: What is Baudot code? A: Baudot code is an early 5-bit character encoding for teleprinters, devised by Emile Baudot and later refined by Donald Murray. The standardised form, ITA-2, became the dominant teleprinter and Telex code for much of the 20th century. Q: How does 5-bit code fit letters, digits, and punctuation? A: Five bits give only 32 combinations, which is too few for everything. ITA-2 solves this with two shift states. Two special codes, LTRS and FIGS, switch between a letters set and a figures set, so most code values have two meanings depending on the active shift. Q: What are the LTRS and FIGS codes? A: LTRS (binary 11111) switches into the letters set and FIGS (binary 11011) switches into the figures set. This encoder tracks the current shift and only emits a shift code when the next character requires the other set, just like a real teleprinter. Q: Why are space and carriage return special? A: Space, carriage return, and line feed have the same code in both the letters and figures sets, so no shift is needed to send them. The encoder treats them as shared control codes and leaves the current shift state unchanged. Q: Which characters cannot be encoded? A: Lower-case is folded to upper-case, and any character with no ITA-2 representation — many symbols and all accented letters — is skipped. The tool lists exactly which characters it dropped so nothing disappears silently. #### BCD (Binary-Coded Decimal) Converter URL: https://geratools.com/bcd-converter Convert a decimal number to Binary-Coded Decimal (BCD) where each digit becomes a 4-bit nibble, and decode 8-4-2-1 BCD back to decimal. Includes packed and unpacked views. How to use: 1. Pick a direction: Choose decimal-to-BCD to encode digits, or BCD-to-decimal to decode a 4-bit-per-digit string. 2. Enter your value: Type a whole decimal number, or a binary string whose length is a multiple of four when decoding. 3. Read the nibbles: Each decimal digit is shown as its own 4-bit group so you can verify the 8-4-2-1 weighting at a glance. FAQ: Q: What is Binary-Coded Decimal? A: BCD represents each decimal digit (0 through 9) with its own fixed 4-bit binary group, called a nibble. Unlike pure binary, the digits are kept separate, so 25 becomes 0010 0101 rather than 11001. Q: What is the difference between packed and unpacked BCD? A: Packed BCD stores two decimal digits in one byte (one nibble each). Unpacked BCD uses a full byte per digit, with the high nibble unused or set to a fill value. This tool shows the packed nibble groups. Q: Why are nibble values above 1001 invalid in BCD? A: Each BCD nibble can only encode the digits 0 through 9, so binary values 1010 (10) through 1111 (15) are not valid BCD codes. The decoder flags any nibble in that range as an error. Q: Where is BCD used? A: BCD appears in digital clocks, calculators, financial systems, and instrumentation where exact decimal representation matters and where converting to a seven-segment display is simpler with digit-aligned bits. Q: Does BCD waste space compared to binary? A: Yes. BCD uses four bits per digit but a single nibble can represent values up to 15, so codes 10 to 15 go unused. Pure binary is more compact, but BCD avoids decimal rounding and simplifies digit display. Q: How does BCD addition work? A: Add the nibbles with a binary adder, then apply the add-6 correction: whenever a nibble result exceeds 9 or produces a half-carry, add 0110 to skip the six invalid codes and propagate the correct decimal carry. x86 exposes this as the DAA instruction. Q: What does a C, D, or F nibble at the end of packed BCD mean? A: It is a sign nibble, not data corruption. Mainframe packed-decimal conventions use 1100 (C) for positive, 1101 (D) for negative, and 1111 (F) for unsigned values, stored as the final nibble of the field. #### Bencode Encoder/Decoder URL: https://geratools.com/bencode-encode Encode JSON into BitTorrent's bencode wire format and decode bencoded data back to JSON. Supports byte strings, integers, lists, and lexicographically-keyed dictionaries per the BEP-3 spec. Runs in your browser. How to use: 1. Pick a mode: Choose Encode to turn JSON into bencode, or Decode to turn bencoded text back into JSON. 2. Enter your data: For encoding, paste JSON such as an object or array. For decoding, paste a bencoded string like d3:foo3:bare. 3. Read the result: The converted value appears instantly. Dictionary keys are sorted lexicographically on encode to produce a canonical, valid result. FAQ: Q: What is bencode? A: Bencode is the simple binary-safe serialization format used by BitTorrent for .torrent files and tracker responses. It encodes four types: byte strings, integers, lists, and dictionaries, each with an unambiguous prefix so the data is self-delimiting. Q: How are the four bencode types written? A: A byte string is its length, a colon, then the bytes (4:spam). An integer is i, the number, then e (i42e). A list is l, its items, then e. A dictionary is d, alternating key/value pairs, then e, with keys as strings sorted in raw byte order. Q: Why are dictionary keys sorted? A: The spec requires dictionary keys to appear in sorted order so that any given data structure has exactly one canonical encoding. This is essential for computing a stable info-hash from a torrent file. This tool sorts keys lexicographically on encode. Q: Does bencode support floats or booleans? A: No. Bencode has no native float or boolean type — only strings, integers, lists, and dictionaries. JSON booleans and floats cannot be represented, so this tool reports an error if you try to encode them. Q: Is my data uploaded anywhere? A: No. All encoding and decoding runs locally in your browser using JavaScript, so torrent metadata and any private data stay on your device. #### Big5 Encoder/Decoder URL: https://geratools.com/big5-encode Encode Traditional Chinese text to Big5 byte pairs shown as hex, or decode Big5 hex bytes back to text. Implements the single-byte ASCII range plus the two-byte lead and trail ranges, runs locally in your browser, and flags characters outside the Big5 repertoire. How to use: 1. Pick a direction: Choose whether to encode Traditional Chinese text into Big5 hex bytes, or decode Big5 hex bytes back into text. 2. Enter your input: For encoding, paste Traditional Chinese text. For decoding, enter the bytes as space- or comma-separated hex values. 3. Copy the result: The output updates instantly; click copy to put it on your clipboard. Characters Big5 cannot store are flagged. FAQ: Q: What is Big5? A: Big5 is the dominant legacy encoding for Traditional Chinese, used in Taiwan, Hong Kong, and Macau before UTF-8 became standard. It stores the thousands of Traditional Chinese characters as two-byte sequences while keeping ASCII single-byte. Q: How many bytes per character? A: ASCII characters take one byte (0x00 to 0x7F). Each Chinese character takes two bytes: a lead byte from 0x81 to 0xFE and a trail byte from 0x40 to 0x7E or 0xA1 to 0xFE, leaving a gap in the trail range. Q: Why might a character be unmapped? A: Big5 covers Traditional Chinese and ASCII, not Simplified-only characters, many rare ideographs, emoji, or other scripts. Those have no Big5 bytes and are flagged with ?? when encoding so nothing is silently lost. Q: Is Big5 the same as GBK? A: No. GBK / GB2312 encodes Simplified Chinese with a different byte layout, and Big5 encodes Traditional Chinese. The same logical character generally has different bytes in each, so the encoding name must travel with the data. Q: Does the conversion happen locally? A: Yes. The Big5 table is built in your browser from the native decoder and used locally for both encoding and decoding. No text is sent to any server. #### Caverphone Encoder URL: https://geratools.com/caverphone-encode Free Caverphone 2.0 encoder (David Hood, 2004). Produce a 10-character phonetic code tuned for New Zealand and Australian name matching. Runs entirely in your browser. How to use: 1. Enter a name: Type a surname or word into the input field. 2. Read the 10-character code: Caverphone 2.0 always returns exactly ten characters, right-padded with the digit 1. 3. Compare names: Enter spelling variants and check whether their codes match to confirm a phonetic link. FAQ: Q: What is Caverphone designed for? A: Caverphone was created for the Caversham project at the University of Otago to match often-misspelled New Zealand surnames from the late 1800s and early 1900s. It handles NZ, Australian and English pronunciations well. Q: Why is the code always 10 characters? A: Caverphone 2.0 fixes the output length at ten characters, right-padding short codes with the digit 1. This makes codes easy to store in fixed-width fields and compare directly. Q: How is it different from Soundex? A: Caverphone applies a long, ordered list of substitution rules rather than a single letter table, so it captures more pronunciation nuance and is better tuned to the names it was built for. Q: Is this Caverphone 1.0 or 2.0? A: This is Caverphone 2.0, the revised 2004 specification, which is more accurate and the version most libraries implement today. Q: Does it work outside New Zealand? A: It works on any English-style name but is most accurate for the NZ/Australian/English names it was designed for. For German names use Cologne Phonetics; for general English use Metaphone. #### TLS Certificate Decoder (PEM) URL: https://geratools.com/certificate-decoder Decodes a PEM X.509 certificate with a JavaScript ASN.1 parser to show subject and issuer DN, Subject Alternative Names, validity period, signature algorithm, key type and size, and the CA flag. Inspect TLS certificates offline with no OpenSSL and nothing sent to a server. How to use: 1. Paste the certificate: Copy the full PEM block including the BEGIN and END CERTIFICATE lines and paste it into the box. 2. Decode: The tool base64-decodes the body to DER and walks the ASN.1 structure entirely in your browser. 3. Review the fields: Read the subject, issuer, validity window, signature algorithm, key size, CA flag and the full list of Subject Alternative Names. FAQ: Q: Is my certificate uploaded anywhere? A: No. All parsing happens in your browser using a JavaScript ASN.1 decoder. The PEM text never leaves your machine, so it is safe to inspect internal or production certificates. Q: What is the difference between the subject CN and the SANs? A: Modern browsers ignore the subject Common Name for hostname matching and use only the Subject Alternative Names. A certificate must list every hostname it should serve in the SAN extension, so the SAN list is what actually matters for validation. Q: Why does it say the certificate is expired? A: The tool compares the notAfter date in the validity field against your computer's current clock. If notAfter is in the past the certificate is expired and browsers will reject it. Check that your system clock is correct if the result looks wrong. Q: Can it decode a private key or a CSR? A: No. This tool only decodes X.509 certificates that begin with BEGIN CERTIFICATE. Private keys and certificate signing requests use different ASN.1 structures and are not parsed here. Q: Does it verify the certificate chain or signature? A: No. It decodes and displays the certificate fields but does not cryptographically verify the signature or build a trust chain to a root CA. Use it for inspection, not for trust decisions. #### Character Frequency Map URL: https://geratools.com/char-count-encode Counts each unique character in your text and outputs a frequency table sorted from most to least common. Iterates by Unicode code point and offers whitespace-ignoring and case-folding options. Runs in your browser. How to use: 1. Paste your text: Enter any string, code snippet, or document into the input box. 2. Choose counting options: Optionally ignore whitespace and fold case so uppercase and lowercase versions of a letter are merged. 3. Read or copy the table: The descending frequency table appears instantly and can be copied as tab-separated count and character pairs. FAQ: Q: How are characters counted? A: The tool iterates over the text by Unicode code point rather than by UTF-16 unit, so accented letters and most emoji are counted as a single character instead of being split apart. Q: How are whitespace characters shown? A: Invisible characters are labelled in the table as (space), (tab), (newline), or (carriage return) so you can see their counts. You can also hide them entirely with the ignore-whitespace option. Q: What is character frequency analysis used for? A: It is the classic first step in breaking simple substitution ciphers, where the most common ciphertext letter likely maps to E in English. It is also handy for spotting unexpected characters or padding in data. Q: How are ties in the count broken? A: Characters that occur the same number of times are ordered by their Unicode code point. This keeps the table deterministic so the same input always produces the same ordering. #### TCF Consent String Encoder (IAB v2.x) URL: https://geratools.com/consent-string-encoder Accepts purpose-consent and legitimate-interest selections, a vendor consent range, and policy fields, and encodes them into a valid base64url TCF core consent string following the IAB TC String specification. Used by CMP developers and ad-tech QA engineers to generate test consent payloads without a running CMP. How to use: 1. Set the policy fields: Choose the CMP ID, vendor list version, consent-screen and policy version. These populate the fixed header section of the TC string. 2. Select purposes and vendors: Tick the purposes the user consented to, the purposes under legitimate interest, and enter the vendor IDs that have consent. 3. Copy the encoded string: The tool builds the bit field and outputs a base64url TC core string ready to drop into a __tcfapi test or a query parameter. FAQ: Q: What is a TCF consent string? A: It is a compact, base64url-encoded record of a user's consent choices under the IAB Europe Transparency and Consent Framework. Ad-tech vendors read it to decide whether they may process personal data for purposes like ad personalisation and measurement. Q: Does this produce a fully spec-complete string with all segments? A: It encodes the TC core string segment, which carries the version, timestamps, CMP fields, purpose consents, purpose legitimate interests, and a vendor consent bit field. It is intended for generating test payloads, not for replacing a certified production CMP that may append publisher and out-of-band segments. Q: Why are timestamps in the string? A: The spec encodes Created and LastUpdated as deciseconds (tenths of a second) since the Unix epoch, each in 36 bits. They let downstream vendors know how fresh the consent record is. This tool stamps both with the current time. Q: What are the 24 purposes? A: TCF v2 defines a standard list of processing purposes, for example purpose 1 (store and access information on a device) and purpose 3 (create a personalised ads profile). A user can consent to each independently, and some can also rely on legitimate interest. Q: Is anything sent to a server? A: No. The entire bit-packing and base64url encoding runs in your browser. Your selected purposes and vendor IDs never leave the page, which makes it safe for QA use. #### Data URI to File Converter URL: https://geratools.com/data-uri-to-file Free in-browser data URI decoder. Paste a data: URI, see its MIME type and size, preview images inline, and download the decoded binary file with the correct extension. Handles base64 and percent-encoded payloads. Everything runs locally — nothing is uploaded. How to use: 1. Paste the data URI: Paste the full string starting with data: — including the MIME type and the base64 (or percent-encoded) payload. 2. Check the detected details: The tool shows the MIME type, encoding, decoded size and a suggested file extension. Images are previewed inline. 3. Download the file: Optionally set a filename, then click Download to save the decoded bytes as a real file with the correct extension. FAQ: Q: What is a data URI? A: A data URI embeds a file directly inside a string using the form data:[mime];base64,[payload]. They are common in CSS, HTML and JSON to inline small images, fonts or icons. This tool reverses the embedding, recovering the original file. Q: Does it handle non-base64 data URIs? A: Yes. If the header does not include the ;base64 flag, the payload is treated as percent-encoded text — the tool URL-decodes it and encodes the result as UTF-8 bytes for download. Most binary assets use base64, which is decoded with the browser's atob. Q: Is my data uploaded anywhere? A: No. Decoding happens entirely in your browser, and the download is produced from an in-memory Blob object URL. The data URI you paste — which may contain private images or documents — never leaves your machine. Q: How is the file extension chosen? A: The extension comes from the MIME type using a built-in map (for example image/png becomes .png, application/pdf becomes .pdf). For an unrecognised type the tool falls back to the MIME subtype or to .bin for application/octet-stream. Q: Why does the download show an image preview first? A: When the MIME type starts with image/, the original data URI can be rendered directly in an img tag, so you can confirm you decoded the right asset before saving it. Non-image types skip the preview and go straight to the download button. #### Decimal Char Code Converter URL: https://geratools.com/decimal-text Outputs the decimal Unicode code point of each character in your text, and rebuilds text from space-separated decimal code points. Handles emoji and astral characters as single values. Runs entirely in your browser. How to use: 1. Pick a direction: Choose Text to decimal to list code points, or Decimal to text to rebuild a string. 2. Enter the input: Type text to convert, or paste space-separated decimal code points to decode. 3. Copy the output: The result updates as you type and can be copied with one click. FAQ: Q: Are these byte values or code points? A: They are Unicode code points, not bytes. Each character maps to one decimal number — its position in the Unicode table. For ASCII this matches the byte value, but for higher characters it is the scalar value, not a UTF-8 byte. Q: How are emoji handled? A: An emoji is a single code point above U+FFFF, so it produces one large decimal number such as 128640 for the rocket. The tool reads the string by code point, so it never splits an emoji into surrogate halves. Q: How do I decode a list of numbers? A: Paste the decimal code points separated by spaces. The tool parses each as a number and converts it back to its character with the standard code-point lookup, rebuilding the original string. Q: What range of values is valid? A: Valid Unicode code points run from 0 to 1114111 (U+10FFFF), excluding the surrogate range 55296 to 57343. The decoder rejects values outside this range or non-numeric tokens rather than producing invalid characters. Q: Is this the same as ASCII codes? A: For characters 0 to 127 it is identical to ASCII. Beyond that it extends to the full Unicode range, so it also covers accented letters, symbols, and emoji that plain ASCII cannot represent. #### DMS to Decimal Lat/Lng Converter URL: https://geratools.com/dms-to-lat-lng Convert DMS (degrees, minutes, seconds) coordinates with N/S/E/W hemisphere letters into signed decimal latitude and longitude. Enter each component and get the precise decimal degrees used by mapping APIs, GPS and databases. How to use: 1. Enter the DMS components: Type the degrees, minutes and seconds for latitude and longitude into their fields, then pick the N/S and E/W hemisphere for each. 2. Read the decimal result: The tool combines degrees plus minutes over 60 plus seconds over 3600, then applies the hemisphere sign to give signed decimal degrees. 3. Copy the decimal pair: Copy the comma-separated decimal latitude and longitude to paste into a mapping API, spreadsheet or database. FAQ: Q: What is the formula for DMS to decimal degrees? A: Decimal = degrees + minutes / 60 + seconds / 3600. The result is then made negative if the hemisphere is south (S) or west (W). Q: How do the hemisphere letters affect the sign? A: North (N) and east (E) give positive decimal values. South (S) and west (W) give negative values. The minus sign in decimal coordinates encodes exactly this. Q: Can minutes or seconds be 60 or more? A: No. Minutes and seconds must each be in the range 0 to under 60, just like a clock. Sixty minutes equal one degree and sixty seconds equal one minute, so any value of 60 or more should be carried into the next unit. Q: How precise is the decimal output? A: Decimal degrees are exact arithmetic from the inputs. About six decimal places gives roughly 0.1 metre resolution at the equator, which is more than enough for any consumer mapping use. #### EBCDIC ↔ ASCII Converter URL: https://geratools.com/ebcdic-converter Free EBCDIC to ASCII converter using IBM Code Page 037. Encode ASCII text to EBCDIC byte values in hex, decimal, or binary, and decode EBCDIC bytes back to readable text. Handles the non-contiguous EBCDIC letter layout. Runs entirely in your browser. How to use: 1. Pick a direction: Choose ASCII to EBCDIC to encode text into mainframe byte values, or EBCDIC to ASCII to decode byte values back into text. 2. Choose a byte format: Select hexadecimal, decimal, or binary to match how your byte values are written, for example C7 in hex or 199 in decimal. 3. Enter and read: Type your text or byte values; the conversion updates live. Any character outside Code Page 037 is listed so nothing is lost silently. FAQ: Q: What is EBCDIC? A: EBCDIC (Extended Binary Coded Decimal Interchange Code) is an 8-bit character encoding created by IBM for its mainframe and midrange systems. It is still used on z/OS and IBM i platforms, which is why converting between EBCDIC and ASCII remains a common task in data migration. Q: Which EBCDIC code page does this use? A: It uses Code Page 037, the US and Canada EBCDIC variant. EBCDIC has dozens of national code pages that differ mainly in the placement of currency symbols and a few punctuation marks, so results for those characters can vary by code page. Q: Why are EBCDIC letters not in a simple sequence? A: In ASCII the letters A to Z occupy consecutive codes, but in EBCDIC they are split into blocks with gaps. The letters A to I, J to R, and S to Z each sit in separate ranges. This is a legacy of the punched-card column layout EBCDIC was designed around and is a classic source of sorting bugs. Q: What happens to characters not in the code page? A: When encoding, any character with no Code Page 037 equivalent is skipped and listed below the output. When decoding, a byte that has no printable CP037 character is shown as a replacement marker so you can see exactly where it occurred. Q: Does the conversion happen on a server? A: No. The full Code Page 037 table is built into the tool and all conversion runs locally in your browser. No text or byte data is uploaded. #### EBCDIC Encoder/Decoder URL: https://geratools.com/ebcdic-encode Convert ASCII text to IBM EBCDIC and back using code page 037, the standard US/Canada English mainframe encoding. Each character maps to a single hex byte, with a reverse decoder for inbound mainframe data. Runs entirely in your browser. How to use: 1. Choose a direction: Select ASCII to EBCDIC to encode, or EBCDIC to ASCII to decode mainframe hex bytes. 2. Enter your data: Type text to encode, or paste space-separated EBCDIC hex bytes such as C8 85 93 93 96 to decode. 3. Copy the result: Copy the hex bytes or recovered text for use with mainframe systems or data files. FAQ: Q: What is EBCDIC? A: EBCDIC, the Extended Binary Coded Decimal Interchange Code, is the 8-bit character encoding used by IBM mainframes and midrange systems such as z/OS and the AS/400. It predates and differs entirely from ASCII. Q: Which EBCDIC code page does this use? A: It uses code page 037 (CP037), the common US and Canada English EBCDIC variant. Other code pages exist for other languages, so always confirm which one your mainframe partner uses before exchanging data. Q: Why are the letters not in a continuous run? A: In EBCDIC the alphabet is split across non-contiguous ranges, with gaps between groups of letters. This means you cannot do simple arithmetic on byte values to step through the alphabet the way you can in ASCII. Q: What happens to non-ASCII characters? A: This tool maps the ASCII range, codepoints 0 to 127, to their CP037 bytes. Characters above that range are reported as skipped, since their mapping depends on the specific national code page in use. Q: When would I actually need this? A: Whenever you integrate with a legacy IBM mainframe: reading fixed-width data files, building screen-scraping or file-transfer bridges, or debugging why text from a host system looks like garbage when read as ASCII. #### ECEF to Lat/Lng Converter URL: https://geratools.com/ecef-to-lat-lng Convert ECEF Cartesian coordinates (X, Y, Z in metres) to WGS-84 geodetic latitude, longitude and ellipsoidal altitude. Uses Bowring's closed-form method with the exact WGS-84 ellipsoid constants. How to use: 1. Enter X, Y and Z: Type the ECEF Cartesian coordinates in metres. The origin is Earth's center of mass. 2. Read the geodetic result: The tool returns WGS-84 latitude, longitude and ellipsoidal altitude. 3. Copy the result: Use the copy button to grab the lat, lng, altitude triple. FAQ: Q: What are ECEF coordinates? A: Earth-Centered, Earth-Fixed coordinates describe a point with three Cartesian values X, Y and Z, measured in metres from Earth's center of mass. The axes rotate with the planet, so a fixed point on the ground has constant ECEF values. Q: Which ellipsoid does this use? A: It uses the WGS-84 ellipsoid, the global reference for GPS, with a semi-major axis of 6378137 metres and a flattening of 1/298.257223563. The same model underlies most consumer positioning. Q: What is ellipsoidal altitude? A: Ellipsoidal altitude is the height above the WGS-84 ellipsoid, not above mean sea level. To get height above sea level you must apply a geoid model, which differs from the ellipsoid by tens of metres in places. Q: Why use Bowring's method? A: Bowring's closed-form formula converts ECEF to geodetic latitude in a single non-iterative step with sub-millimetre accuracy at typical altitudes, avoiding the slow iteration that a naive approach would need. Q: What if all three values are zero? A: X = Y = Z = 0 is Earth's center, where latitude and longitude are undefined. The tool rejects that input rather than returning a meaningless answer. #### Excel Column ↔ Number Converter URL: https://geratools.com/excel-column-number-converter Convert Excel-style column letters such as A, AB, or ZZZ to their 1-based integer index and back. Uses true bijective base-26 arithmetic, the same scheme Excel and Google Sheets use. How to use: 1. Choose what you have: Switch between letters-to-number when you have a column label, or number-to-letters when you have an index. 2. Type the value: Enter a column label like AB, or a positive integer like 28. Letters are case-insensitive. 3. Read the converted value: The converter instantly returns the matching number or label, with the full base-26 breakdown shown below. FAQ: Q: How does Excel number its columns? A: Excel uses bijective base-26: A=1, B=2, up to Z=26, then AA=27, AB=28, and so on. There is no zero digit, which is why it is called bijective rather than ordinary base-26. Q: What is the formula for letters to a number? A: For each letter from left to right, multiply the running total by 26 and add the letter's position (A=1 … Z=26). So AB is 1×26 + 2 = 28. Q: How do you convert a number back to letters? A: Repeatedly subtract 1, take the remainder modulo 26 as the next letter from the right, then integer-divide by 26. This adjustment handles the missing zero digit correctly. Q: What is the maximum Excel column? A: Modern Excel worksheets stop at column XFD, which is index 16384. This converter accepts larger values too, since the same bijective base-26 math extends without limit. Q: Are lowercase letters accepted? A: Yes. Column labels are case-insensitive, so ab and AB both convert to 28. The output label is always shown in uppercase to match spreadsheet conventions. #### Excel Serial Date Converter URL: https://geratools.com/excel-serial-date-converter Convert an Excel serial date number to a calendar date and back, in both the 1900 and 1904 date systems. Correctly reproduces the famous 1900 leap-year bug, including the phantom 29 February 1900 at serial 60. How to use: 1. Pick the date system: Choose the 1900 system used by Windows Excel by default, or the 1904 system used by older Mac workbooks. 2. Enter the value and direction: Convert a serial number to a date, or a date to its serial number. Fractional serials carry a time of day. 3. Read the calendar date and weekday: The result shows the date, the weekday, and a note if the value lands on the phantom 1900 leap day. FAQ: Q: What is an Excel serial date? A: Excel stores dates as numbers counting days from an epoch. In the 1900 system serial 1 is 1 January 1900, and the integer part is the day while any fraction is the time of day, so 0.5 means noon. Q: What is the 1900 leap-year bug? A: Excel incorrectly treats 1900 as a leap year and includes a 29 February 1900 that never existed at serial 60. The tool reproduces this so its numbers match Excel exactly, and flags serial 60 as the phantom day. Q: How do the 1900 and 1904 systems differ? A: The 1904 system, used by some legacy Mac workbooks, counts from 1 January 1904 and has no leap-year bug. The same calendar date has a different serial number in each system, so pick the one your file uses. Q: How is the time of day represented? A: The fractional part of a serial number is the fraction of a day elapsed since midnight. So 44197.75 is 18:00 on the date for serial 44197, because 0.75 of a day is 18 hours. Q: What range of dates is supported? A: Serial numbers are not negative in Excel, so the tool requires a value of at least 1 for serials and rejects dates before the chosen epoch when converting the other way. #### Fixed-Point Converter URL: https://geratools.com/fixed-point-converter Free Qm.n fixed-point converter. Turn any decimal into its scaled integer, two's-complement binary and hex form for a chosen integer/fractional bit split, with overflow detection and quantization error. Runs in your browser. How to use: 1. Enter a real number: Type the decimal value you want to encode, for example 3.14159. 2. Choose the bit split: Set the number of integer bits (m) and fractional bits (n) for your Qm.n format. 3. Read the encoding: The tool shows the scaled integer, binary, hex, the value actually represented after rounding, and the quantization error. FAQ: Q: What does Qm.n mean? A: Qm.n is a signed fixed-point format with m integer bits and n fractional bits, plus one sign bit, giving m+n+1 total bits. The stored integer equals the real value multiplied by 2 to the power n. Q: How is the binary value computed? A: The tool multiplies your number by 2^n, rounds to the nearest integer, then encodes that as a two's-complement integer of m+n+1 bits. This is the exact pattern stored in a register. Q: What is the resolution of a fixed-point format? A: The smallest representable step is 2 to the power minus n. More fractional bits (larger n) give finer resolution but a smaller integer range for the same total width. Q: Why does my value show a quantization error? A: Fixed-point can only represent multiples of its resolution. If your number falls between two steps it is rounded, and the difference is the quantization error the tool reports. Q: Is this calculation done online? A: No. Everything is computed locally in your browser using JavaScript. Nothing is uploaded, so the tool is private and works offline once loaded. #### GB2312 / GBK Encoder/Decoder URL: https://geratools.com/gb2312-encode Encode Simplified Chinese text to GBK / GB2312 byte sequences shown as hex, or decode GBK hex bytes back to text. Handles single-byte ASCII plus two-byte Chinese characters using the GBK superset, runs locally in your browser, and flags anything outside the repertoire. How to use: 1. Pick a direction: Choose whether to encode Simplified Chinese text into GBK / GB2312 hex bytes, or decode GBK hex bytes back into text. 2. Enter your input: For encoding, paste Simplified Chinese text. For decoding, enter the bytes as space- or comma-separated hex values. 3. Copy the result: The output updates instantly; click copy to put it on your clipboard. Characters GBK cannot store are flagged. FAQ: Q: What is the difference between GB2312 and GBK? A: GB2312 is the original 1980 standard covering common Simplified Chinese characters. GBK is a backward-compatible superset that adds thousands more characters. Any GB2312 byte sequence is valid GBK, so this tool uses the wider GBK table for both directions. Q: How many bytes per character? A: ASCII characters take one byte (0x00 to 0x7F). Each Chinese character takes two bytes: a lead byte from 0x81 to 0xFE and a trail byte from 0x40 to 0xFE, excluding 0x7F. The two-byte form is how GBK packs the large character set. Q: Why might a character be unmapped? A: GBK covers Simplified Chinese and ASCII. Traditional-only characters not shared with the set, emoji, and non-Chinese scripts have no GBK bytes and are flagged with ?? on encoding so you can see what was dropped. Q: Is GBK the same as Big5? A: No. Big5 encodes Traditional Chinese with a different layout; GBK encodes Simplified Chinese. The same character usually has different bytes in each, so always store the encoding name alongside the bytes. Q: Does the conversion run locally? A: Yes. The GBK table is built in your browser from the native decoder and applied locally for both encoding and decoding. No text is uploaded to a server. #### GPX to FIT Converter (Garmin) URL: https://geratools.com/gpx-to-fit Free GPX to FIT converter. Reads GPX track points (latitude, longitude, elevation, time) and encodes a valid Garmin .fit activity file with correct semicircle coordinates, FIT timestamps and CRC. Importable to Garmin devices and Connect. GPS data never leaves your browser. How to use: 1. Upload your GPX file: Select a GPX file containing one or more track segments. It is parsed locally in your browser. 2. Let it encode the FIT: The tool reads each track point's latitude, longitude, elevation and time, then writes a valid FIT binary with the correct headers and CRC. 3. Download the .fit: Download the generated .fit file and import it into your Garmin device or Garmin Connect. FAQ: Q: How does GPX differ from FIT? A: GPX is a plain-text XML format for sharing tracks and waypoints. FIT (Flexible and Interoperable Data Transfer) is Garmin's compact binary format used by their devices and Connect platform. Converting lets a track recorded elsewhere be imported as a Garmin activity. Q: How are coordinates encoded in FIT? A: FIT stores latitude and longitude as 32-bit signed semicircles, where one degree equals 2^31 / 180 semicircles. The converter multiplies each decimal degree by that factor and rounds to an integer, which is exactly how Garmin devices store position. Q: What fields are written? A: A file_id message marks it as an activity, then one record message per track point carries timestamp, position_lat, position_long and altitude. This is the minimum a device or Garmin Connect needs to recognise and display the track. Q: Does the file include a valid checksum? A: Yes. FIT requires a 2-byte CRC over the header and the data records, computed with Garmin's specified CRC-16 table algorithm. The tool appends the correct CRC so the file passes validation on import. Q: Is my GPS data uploaded? A: No. The GPX is parsed and the FIT is generated entirely in your browser using the File API. Your location history never leaves your device. #### GPX to KML Converter URL: https://geratools.com/gpx-to-kml Free GPX to KML converter that runs 100% in your browser. Parses GPX waypoints, tracks and routes and emits KML Placemarks and LineStrings for Google Earth and Maps. Your location data never leaves your device — no upload, no server. How to use: 1. Paste or load GPX: Paste your GPX XML into the box, or open a .gpx file from your device. Nothing is uploaded. 2. Convert: The tool parses waypoints, track segments and routes with the browser's DOMParser and builds matching KML. 3. Copy or download: Copy the KML or download a .kml file to open in Google Earth, Google My Maps or any KML viewer. FAQ: Q: What is the difference between GPX and KML? A: GPX is the GPS Exchange Format used by Garmin, Strava and most GPS devices. KML (Keyhole Markup Language) is Google's format for Google Earth and Maps. Both store points and lines but use different XML tags, so a conversion remaps the elements. Q: Does this keep my track timestamps and elevation? A: Track point coordinates and elevation are preserved as KML uses lon,lat,ele tuples in LineString coordinates. KML LineStrings do not carry per-point timestamps, so time data on individual track points is not represented in the output geometry. Q: Are waypoints and routes converted too? A: Yes. GPX waypoints (wpt) become KML point Placemarks with their name and description, and both tracks (trk) and routes (rte) become Placemarks containing a LineString of the ordered coordinates. Q: Is my GPS data uploaded anywhere? A: No. The entire conversion happens in your browser using DOMParser and string templating. Your route and location data never leaves your device and nothing is logged or transmitted. Q: Why is my output empty? A: An empty result usually means the input was not valid GPX or contained no wpt, trkpt or rtept elements. Check that you pasted the full XML including the gpx root element and at least one point. Some apps export a .gpx that is actually TCX or FIT internally — confirm it is real GPX XML. Q: How do I keep timestamps for animated playback in Google Earth? A: Standard KML LineStrings carry no per-vertex time, so plain conversion drops timestamps. For time-animated playback you need KML with a gx:Track element (a Google extension that pairs 'when' times with coordinates), which some dedicated converters produce. This tool outputs static LineStrings suited to drawing the route on the terrain. Q: Why does my converted track show a long straight line across the map? A: Two track segments were merged with a gap between them — usually because recording was paused and resumed some distance away. KML connects consecutive LineString vertices, so the recording gap is drawn as a straight connector. Split the track into separate files if you want the segments shown independently. #### .htaccess to Nginx Rewrite Converter URL: https://geratools.com/htaccess-converter Parses RewriteRule and RewriteCond lines and emits equivalent Nginx location, rewrite, and return blocks. Handles common flag combinations like R=301, L, QSA, NC, F, and G. Runs entirely in-browser. How to use: 1. Paste your rules: Drop the RewriteRule and RewriteCond lines from your .htaccess file into the text area. A sample loads by default. 2. Read the Nginx output: The converter emits matching location, rewrite, and return blocks, mapping flags like R=301 and L to their Nginx equivalents. 3. Review the notes: Check the conversion notes for any approximations, then adapt the output to your server block before deploying. FAQ: Q: Which Apache flags are supported? A: The converter handles the common subset: R and R=301/302 for redirects, L for last, QSA for query-string append, NC for case-insensitive, F for forbidden (403), and G for gone (410). Less common flags are ignored. Q: How is a RewriteCond handled? A: A RewriteCond that tests HTTP_HOST, REQUEST_URI, QUERY_STRING, or HTTPS becomes an Nginx if guard around the rule. File-existence checks against REQUEST_FILENAME map to try_files instead, which the notes explain. Q: Why does Nginx not chain conditions like Apache? A: Apache applies all preceding RewriteCond lines to one RewriteRule. Nginx if blocks do not chain, so multiple conditions are emitted separately and flagged in the notes so you can combine them manually. Q: Is the output production-ready? A: Treat it as a strong first draft. Apache per-directory context and Nginx location context differ, so always test the generated rules against real URLs and confirm redirect status codes before going live. Q: Does my .htaccess get uploaded? A: No. Parsing and conversion happen entirely in your browser with JavaScript. Your rules, including any internal paths or hostnames, never leave your device. #### ISO 3166 Country Code Converter URL: https://geratools.com/iso-country-code-converter Free ISO 3166-1 country code converter. Enter a country name, alpha-2 code (DE), alpha-3 code (DEU), or numeric code (276) and instantly get all three official representations plus the English short name. Runs entirely in your browser. How to use: 1. Enter a country or code: Type a country name, a two-letter alpha-2 code, a three-letter alpha-3 code, or a numeric code into the input box. 2. Read all three codes: The converter resolves your input and shows the matching alpha-2, alpha-3, and numeric codes alongside the official English short name. 3. Copy what you need: Use the copy button next to any field to place that code on your clipboard for use in your code, spreadsheet, or document. FAQ: Q: What is the difference between ISO 3166-1 alpha-2 and alpha-3 codes? A: Alpha-2 is a two-letter code such as DE for Germany, used in domain names and most APIs. Alpha-3 is a three-letter code such as DEU, which is more mnemonic and used in passports and many international standards. Both identify the same country. Q: What is the ISO 3166-1 numeric code for? A: The numeric code is a three-digit identifier such as 276 for Germany. It is independent of any script or language, so it is useful where Latin letters cannot be used and it tends to remain stable even when a country's alphabetic codes are reassigned. Q: Can I look up a country by its name? A: Yes. Type a full or partial English short name and the converter matches it to the official ISO entry, then shows the alpha-2, alpha-3, and numeric codes. An exact name match is preferred, otherwise the first partial match is shown. Q: Why are some numeric codes shown with leading zeros? A: ISO 3166-1 numeric codes are always three digits, so smaller values are zero-padded — for example Afghanistan is 004 and Solomon Islands is 090. The converter accepts your input with or without leading zeros and always displays the canonical padded form. Q: Is this list of countries up to date? A: The converter uses the currently assigned ISO 3166-1 codes, including recent changes such as Türkiye and North Macedonia. ISO occasionally adds or retires entries, so for legally critical use always cross-check against the official ISO Online Browsing Platform. #### KML to GPX Converter URL: https://geratools.com/kml-to-gpx Free KML to GPX converter that runs entirely in your browser. Extracts Placemarks, Points, LineStrings and Polygons from KML and emits standards-compliant GPX 1.1. Handles MultiGeometry and nested folders — your location data never leaves your device. How to use: 1. Paste or load KML: Paste your KML XML into the box or open a .kml file from your device. Nothing is uploaded. 2. Convert: The tool reads every Placemark with DOMParser and maps Points to waypoints and LineStrings to GPX tracks. 3. Copy or download: Copy the GPX or download a .gpx file to import into Garmin Connect, Strava, Komoot or any GPS device. FAQ: Q: What does the converter do with KML Points? A: Each Point inside a Placemark becomes a GPX waypoint (wpt) with the latitude and longitude split out of the KML coordinate tuple, plus the Placemark name and description if present. Q: How are lines and polygons handled? A: A LineString becomes a GPX track (trk) with one track segment of trkpt points. A Polygon's outer boundary is also exported as a track so the shape is preserved, since GPX has no native polygon type. Q: Does it understand the lon,lat ordering difference? A: Yes. KML stores coordinates as lon,lat,ele while GPX uses separate lat and lon attributes. The converter swaps the order so your points land in the right place rather than mirrored across the globe. Q: Will nested folders and MultiGeometry work? A: Yes. The parser walks all Placemarks regardless of how deeply they are nested in Folders, and it iterates every geometry inside a MultiGeometry so multi-part features are not dropped. Q: Is my KML uploaded anywhere? A: No. The conversion runs locally in your browser with DOMParser and string building. Your location data is never sent to a server, logged or stored. #### Lat/Lng to DMS Converter URL: https://geratools.com/lat-lng-to-dms Convert decimal latitude and longitude into DMS (degrees, minutes, seconds) notation with N/S/E/W hemisphere letters. Enter signed decimal coordinates and get the exact sexagesimal form used on maps, GPS units and nautical charts. How to use: 1. Enter decimal coordinates: Type the latitude and longitude in signed decimal degrees, for example 51.507351 and -0.127758. Negative latitude is south, negative longitude is west. 2. Read the DMS result: The tool splits each value into whole degrees, whole minutes and decimal seconds, then attaches the correct N/S or E/W hemisphere letter. 3. Copy the formatted output: Copy the combined DMS string to paste into a chart, label or GPS device that expects sexagesimal coordinates. FAQ: Q: How is a decimal coordinate split into degrees, minutes and seconds? A: The whole-number part is the degrees. Multiply the fractional part by 60 to get minutes; the whole part of that is the minutes. Multiply the remaining fraction by 60 again to get the seconds. Q: What range are valid latitude and longitude values? A: Latitude must be between -90 and +90 degrees and longitude between -180 and +180 degrees. Values outside these ranges are not valid geographic coordinates. Q: How do the sign and the hemisphere letter relate? A: A positive latitude is north (N) and a negative latitude is south (S). A positive longitude is east (E) and a negative longitude is west (W). The DMS form uses the letter instead of a minus sign. Q: Why does my converted value have 60 seconds rounded? A: Rounding seconds to whole numbers can occasionally produce 60. This tool keeps a few decimal places of seconds to avoid that and to preserve precision; round only at display time if needed. #### Lat/Lng to MGRS Converter URL: https://geratools.com/lat-lng-to-mgrs Convert WGS-84 decimal latitude and longitude to an MGRS (Military Grid Reference System) string. Get the grid zone designator, the 100 km square ID and the numeric easting/northing at 1 metre precision, as used in military and emergency navigation. How to use: 1. Enter decimal coordinates: Type the WGS-84 latitude and longitude in signed decimal degrees, for example 51.4778 and -0.0014. 2. Read the MGRS string: The tool projects the point to UTM, derives the grid zone designator and 100 km square letters, then truncates the easting and northing to the chosen precision. 3. Copy the grid reference: Copy the full MGRS string to paste into a map, radio report or navigation device. FAQ: Q: What does an MGRS string look like? A: An example is 30U XC 99319 10158. The 30U is the grid zone designator, XC is the 100 km square identifier, and the two five-digit numbers are the easting and northing within that square at 1 metre precision. Q: How are the 100 km square letters chosen? A: The column letter cycles through three alphabets of eight letters keyed to the zone number, and the row letter cycles through a 20-letter sequence keyed to whether the zone is odd or even. Together they uniquely identify a 100 km square within the zone. Q: What precision levels does MGRS support? A: MGRS supports 10 km, 1 km, 100 m, 10 m and 1 m precision by using 1 to 5 digits for each of easting and northing. This tool outputs 1 metre precision with five digits each. Q: Why does MGRS leave out the I and O letters? A: The letters I and O are skipped throughout MGRS because they are easily confused with the digits 1 and 0 when read or transmitted by voice. #### Lat/Lng to Plus Code Converter URL: https://geratools.com/lat-lng-to-pluscode Encode a latitude and longitude into a Plus Code (Open Location Code) of 10, 11 or 12 characters. Uses Google's base-20 pair grid and grid-refinement algorithm for an address-free global location code. How to use: 1. Enter coordinates: Type a latitude between -90 and 90 and a longitude between -180 and 180. 2. Pick a code length: Choose 10 for the standard ~14 m code, or 11 or 12 for finer resolution. 3. Copy the Plus Code: The encoded full Plus Code with its + separator appears immediately. FAQ: Q: What is a Plus Code? A: A Plus Code, formally an Open Location Code, is a short code that represents any location on Earth without needing a street address. It is built by Google and shown in Google Maps as a code like 8FVC9G8F+6X. Q: How long should my code be? A: A 10 character code (8 digits, a +, then 2 more) locates an area about 14 by 14 metres. Adding an eleventh character shrinks that to roughly 3.5 metres and a twelfth to under a metre. Q: What does the + separator mean? A: The plus sign always follows the eighth character. It has no numeric meaning; it simply marks the boundary between the global block and the local part so codes are easy to read and to shorten. Q: Why are letters like A, E and I missing? A: Open Location Code uses a 20 symbol alphabet (23456789CFGHJMPQRVWX) chosen to avoid vowels and characters that form words or look alike, which keeps codes unambiguous across languages. Q: Is this the same as a geohash? A: Both encode coordinates into a short string, but Plus Codes use a base-20 pair grid with a fixed separator and a grid-refinement stage, whereas geohash interleaves bits in base-32. They are not interchangeable. #### LEB128 Encoder/Decoder URL: https://geratools.com/leb128-encoder Encode and decode integers using LEB128, the variable-length integer format used by WebAssembly and DWARF. Supports both unsigned LEB128 and signed SLEB128, with BigInt precision and hex byte output. Runs in your browser. How to use: 1. Choose mode and signedness: Pick encode or decode, then choose unsigned LEB128 or signed SLEB128 to match your data. 2. Enter the value or bytes: To encode, type an integer. To decode, paste the bytes as hex or decimal separated by spaces or commas. 3. Read the result: Encoding returns space-separated hex bytes; decoding returns the integer. Use the copy button to grab the output. FAQ: Q: What is LEB128? A: LEB128 (Little Endian Base 128) is a variable-length encoding for integers. Each byte holds 7 bits of the number plus one continuation flag, so small values take fewer bytes. WebAssembly binaries and the DWARF debug format both use it heavily. Q: What is the difference between unsigned and signed LEB128? A: Unsigned LEB128 encodes non-negative integers by emitting 7-bit groups until the value is exhausted. Signed LEB128, or SLEB128, uses an arithmetic right shift and stops based on the sign bit of the final group, so it can round-trip negative numbers correctly. Q: How is the continuation bit used? A: The high bit (0x80) of each byte is the continuation flag. It is set on every byte except the last, telling the decoder that more 7-bit groups follow. The decoder keeps reading until it sees a byte with that bit cleared. Q: Why are the low bits emitted first? A: LEB128 is little-endian: the least significant 7 bits are written in the first byte and higher groups follow. When decoding, each group is shifted left by an increasing multiple of 7 before being combined. Q: Does it handle very large integers? A: Yes. Both encoding and decoding use JavaScript BigInt, so 64-bit and larger values are exact. The signed decoder also sign-extends correctly so negatives reconstruct without overflow. #### Line Ending Converter (CRLF / LF) URL: https://geratools.com/line-ending-crlf Convert line endings between Windows CRLF, Unix and modern Mac LF, and classic Mac CR. Detects the current style, reports a mixed-endings warning, and rewrites the whole file consistently. Runs in your browser. How to use: 1. Paste your text: Drop in the file or text whose line endings you want to inspect or convert. 2. Read the detected style: The tool reports how many CRLF, LF, and CR breaks it found and warns if the file mixes styles. 3. Choose the target and copy: Pick LF, CRLF, or CR as the target, then copy the rewritten text with every line ending made consistent. FAQ: Q: What is the difference between CRLF, LF, and CR? A: LF is a single line feed (U+000A) used by Unix, Linux, and modern macOS. CRLF is a carriage return followed by a line feed (U+000D U+000A) used by Windows and many network protocols. CR alone (U+000D) was used by classic Mac OS through version 9. Q: Why do mixed line endings cause problems? A: A file with both CRLF and LF confuses version control, shows phantom changes in diffs, and can break shell scripts where a stray carriage return becomes part of a variable. Normalising to one style throughout fixes these silent bugs. Q: How does conversion work safely? A: The tool first reduces every CRLF and lone CR to a single LF, giving a clean baseline. It then expands that LF to the target ending, so converting never doubles up carriage returns or leaves orphaned characters regardless of the input mix. Q: Which ending should I use? A: Use LF for source code, web files, and anything in Git or Unix tooling, which is the modern default. Use CRLF only when a Windows-specific tool, Notepad, or certain protocols require it. CR alone is obsolete and almost never needed today. #### Mac Absolute Time Converter URL: https://geratools.com/mac-absolute-time-converter Convert an Apple Core Foundation CFAbsoluteTime value to a UTC date and back. CFAbsoluteTime counts seconds since 2001-01-01, the Cocoa reference date, and the tool also reports the equivalent Unix timestamp. How to use: 1. Choose the direction: Pick CFAbsoluteTime to date if you have a seconds value, or date to CFAbsoluteTime if you have a UTC date and time. 2. Enter the value: Type a CFAbsoluteTime in seconds, which may be fractional, or an ISO-8601 UTC date such as 2022-01-01T00:00:00Z. 3. Read the result: The tool returns the UTC date with the matching Unix timestamp, or the CFAbsoluteTime value in seconds. FAQ: Q: What is CFAbsoluteTime? A: CFAbsoluteTime is an Apple Core Foundation type measuring seconds since the reference date of midnight on 1 January 2001 in UTC. It underlies NSDate and Date in Cocoa and appears in many macOS and iOS data formats. Q: How does it relate to Unix time? A: The Apple reference date is 978,307,200 seconds after the Unix epoch of 1 January 1970. The tool adds that offset to convert CFAbsoluteTime to a Unix timestamp and a normal date. Q: Why do I sometimes see negative values? A: A CFAbsoluteTime before the 2001 reference date is negative, since it counts backwards from the origin. The tool handles negative values and dates before 2001 correctly. Q: Where will I encounter CFAbsoluteTime? A: It shows up in macOS and iOS plists, Safari and WebKit history and cache files, Spotlight metadata, and other Apple artifacts, which is why forensic and debugging work often needs to decode it. Q: Are fractional seconds supported? A: Yes. CFAbsoluteTime is a floating-point value, so fractional seconds are allowed on input and preserved when converting from a date that carries sub-second precision. #### Maidenhead Locator to Lat/Lng URL: https://geratools.com/maidenhead-to-lat-lng Convert a Maidenhead Locator (QTH grid square) such as IO91WM into the center latitude and longitude. Supports 2, 4, 6 and 8 character grids using the amateur-radio division scheme. How to use: 1. Enter the locator: Type a Maidenhead grid such as IO91, IO91WM or IO91WM12. Case does not matter. 2. Read the coordinates: The tool returns the latitude and longitude of the center of that grid square. 3. Copy the result: Use the copy button to grab the lat, lng pair for a map or logging tool. FAQ: Q: What is a Maidenhead locator? A: The Maidenhead Locator System encodes a position on Earth as a short alphanumeric grid square, widely used by amateur radio operators. A code like IO91WM identifies a small rectangle, and longer codes pinpoint a smaller area. Q: How precise is a 4, 6 or 8 character grid? A: A 2 character field spans 20 deg longitude by 10 deg latitude. A 4 character square is 2 deg by 1 deg, a 6 character subsquare is about 5 by 2.5 arc-minutes, and an 8 character grid narrows that another tenfold. Q: Why does the tool return the center of the square? A: A locator describes an area, not a single point. Returning the geometric center of the cell gives the most representative single coordinate for that grid. Q: Is case sensitivity a problem? A: No. The field and subsquare letters are conventionally upper and lower case respectively, but this converter uppercases the input so IO91wm and IO91WM give the same answer. Q: Which character lengths are supported? A: Two, four, six and eight character locators are accepted. Odd lengths are rejected because the format always alternates a latitude and longitude character in pairs. #### MGRS to Lat/Lng Converter URL: https://geratools.com/mgrs-to-lat-lng Convert a Military Grid Reference System (MGRS) string back to WGS-84 decimal latitude and longitude. Paste a grid reference such as 30U XC 99319 10158 and get precise geographic coordinates via the decoded UTM position and inverse projection. How to use: 1. Paste the MGRS string: Enter a full MGRS reference such as 30U XC 99319 10158. Spaces are optional and letters can be upper or lower case. 2. Read the geographic result: The tool decodes the grid zone, 100 km square and numeric digits to a UTM position, then runs the inverse projection to recover latitude and longitude. 3. Copy the decimal pair: Copy the comma-separated latitude and longitude to paste into a map, API or report. FAQ: Q: What format should the MGRS string be in? A: Use the grid zone designator, the two-letter 100 km square, then equal-length easting and northing digits, for example 30U XC 99319 10158. Spaces are optional; this tool accepts the string with or without them. Q: How is precision recovered from the digits? A: The easting and northing digit groups must be the same length. Five digits each means 1 metre precision; fewer digits mean coarser precision, and the value is scaled to the centre of the implied cell. Q: Why are the I and O letters never present? A: MGRS skips I and O throughout because they look like the digits 1 and 0. A valid MGRS string will never contain them, and this tool rejects them. Q: What datum does the result use? A: The output is WGS-84 decimal latitude and longitude, the datum used by GPS and most modern maps, computed on the WGS-84 ellipsoid. #### NYSIIS Encoder URL: https://geratools.com/nysiis-encode Free NYSIIS encoder (Taft, 1970). Generate the phonetic key used in criminal-justice name matching, reported ~2.7% more accurate than Soundex. Runs in your browser. How to use: 1. Enter a name: Type a surname or word into the input field. 2. Read the key: The NYSIIS key appears in two forms — the classic 6-character key and the full untruncated key. 3. Compare names: Enter spelling variants and confirm they share the same key to detect a phonetic match. FAQ: Q: What does NYSIIS stand for? A: NYSIIS is the New York State Identification and Intelligence System phonetic algorithm, published by Robert Taft in 1970 for matching names in criminal-justice records. Q: How accurate is NYSIIS versus Soundex? A: Studies report NYSIIS is roughly 2.7% more accurate than Soundex for name matching, because it transcodes letter groups and retains more structure rather than using a flat code table. Q: Why are there two keys shown? A: The classic NYSIIS key is truncated to six characters for indexing, but the full untruncated key is also useful for stricter comparison. The tool shows both. Q: How are leading clusters handled? A: Leading MAC becomes MCC, KN becomes N, K becomes C, PH/PF becomes FF and SCH becomes SSS. These transformations normalise common name prefixes before coding. Q: Does NYSIIS keep the first letter? A: Yes. The first letter of the transformed name becomes the first character of the key, then the remaining letters are transcoded and de-duplicated. #### Ordinal Date Converter URL: https://geratools.com/ordinal-date-converter Free ordinal date converter. Turn any Gregorian calendar date into ISO 8601 ordinal format (year plus day-of-year, 1-366) and back again, with correct leap-year handling. Runs entirely in your browser. How to use: 1. Pick a direction: Choose whether you are converting a calendar date to an ordinal date or an ordinal date back to a calendar date. 2. Enter your value: Type a calendar date (year, month, day) or an ordinal date (year and day-of-year from 1 to 366). 3. Read the result: The converted value updates instantly, including the ISO 8601 ordinal string in YYYY-DDD form. FAQ: Q: What is an ISO 8601 ordinal date? A: An ordinal date identifies a day by its year and its position in that year. It is written as YYYY-DDD, where DDD is the day-of-year from 001 to 365 (or 366 in a leap year). For example, 2026-060 is the 60th day of 2026. Q: How is the day-of-year calculated? A: The day-of-year is the count of days from January 1 (day 1) up to and including the target date. The tool sums the lengths of all earlier months in that year plus the day-of-month, adding one extra day in February during leap years. Q: How are leap years handled? A: A year is a leap year if it is divisible by 4, except century years which must be divisible by 400. So 2000 and 2024 are leap years, but 1900 and 2100 are not. Leap years have 366 days, making day 366 (December 31) valid. Q: Is this the same as a Julian day number? A: No. An ordinal date resets to 1 each year, so it only ranges 1-366. A Julian Day Number is a continuous count of days since 4713 BC and is a different system, though both are sometimes loosely called the day number. Q: Does it work for any year? A: Yes. The Gregorian leap-year rule is applied for every year you enter, so conversions are correct for past and future dates. The tool does not adjust for the historical Julian-to-Gregorian switch. #### Plus Code to Lat/Lng Converter URL: https://geratools.com/pluscode-to-lat-lng Decode a full Plus Code (Open Location Code) such as 8FVC9G8F+6X into its center latitude and longitude plus the cell bounds. Implements Google's base-20 pair and grid-refinement decoding. How to use: 1. Paste the Plus Code: Enter a full code such as 8FVC9G8F+6X. The + must follow the eighth character. 2. Read the coordinates: The tool shows the cell center latitude and longitude plus the cell bounds. 3. Copy the result: Use the copy button to grab the center lat, lng pair. FAQ: Q: What input does this tool accept? A: It accepts a full Open Location Code, where the part before the + separator is the global block. Shortened codes that omit the leading characters require a reference location and are not supported here. Q: Why does it return a center and a bounding box? A: A Plus Code names a rectangular cell, not a single point. The center is the best single coordinate, and the bounds tell you how large that cell is, which depends on the code length. Q: How precise is the decoded point? A: A 10 character code resolves to about a 14 metre cell, an 11 character code to roughly 3.5 metres, and a 12 character code to under a metre. The true point lies somewhere within the reported bounds. Q: What if the + is in the wrong place? A: The separator must always follow exactly eight characters and sit at an even position. If it is missing or misplaced the code is invalid, and the tool reports the error rather than guessing. Q: Which characters are valid in a Plus Code? A: Only the 20 symbol alphabet 23456789CFGHJMPQRVWX is allowed, plus the single + separator and trailing 0 padding. Vowels and ambiguous characters are intentionally excluded. #### Google Polyline Decoder URL: https://geratools.com/polyline-decoder Decode a Google Maps encoded polyline string into a list of latitude and longitude points. Implements the official base-64, signed-delta decoding at precision 5 or 6 with full error checking. How to use: 1. Paste the polyline: Paste the encoded polyline string from a routing or maps API. 2. Match the precision: Select precision 5 for Google Maps or 6 for OSRM and similar sources. 3. Copy the points: The decoded lat, lng list appears, one point per line, ready to copy. FAQ: Q: What does the decoder produce? A: It produces the ordered list of latitude and longitude points that were encoded, one per line. Each line is a single coordinate of the original path. Q: Why must I choose the right precision? A: The encoder scaled each coordinate by ten to the precision. Decoding with the wrong precision multiplies or divides every value by a power of ten, putting the points in the wrong place. Match the source exactly. Q: What precision do common APIs use? A: The Google Directions and Maps APIs use precision 5. OSRM version 5 and several other routing engines use precision 6. If unsure, try 5 first and check that the coordinates look plausible. Q: What happens with an invalid string? A: Each character must fall in the base-64 range used by the format. If the string ends mid-value or contains a character outside that range, the tool reports the error instead of producing garbage points. Q: Can I re-encode the points? A: Yes. Paste the decoded points into the Google Polyline Encoder at the same precision to reproduce the original string, allowing for the rounding inherent in the format. #### Google Polyline Encoder / Decoder URL: https://geratools.com/polyline-encoder-decoder Free Google Maps Encoded Polyline tool — convert a list of latitude/longitude points into a compact polyline string and decode any polyline back into coordinates. Implements the official algorithm with selectable precision, all in your browser. How to use: 1. Choose a direction: Pick Encode to turn coordinates into a polyline, or Decode to turn a polyline back into coordinates. 2. Enter your data: For encoding, paste lat,lon pairs one per line. For decoding, paste the encoded polyline string. 3. Copy the result: The converted output appears instantly. Use the Copy button to grab it for the Maps or Directions API. FAQ: Q: What is an encoded polyline? A: It is Google's compact text format for a series of coordinates, used by the Directions, Roads, and Static Maps APIs. Each point is stored as a delta from the previous one, then base64-encoded, which makes long routes far shorter than raw lat/lon lists. Q: What does precision 5 versus 6 mean? A: Precision is the number of decimal places preserved. Most Google APIs use precision 5 (about 1 metre), but some newer endpoints and OSRM use precision 6 (about 0.1 metre). Decoding with the wrong precision shifts every point by a factor of ten. Q: Why are decoded numbers slightly different from my input? A: The format rounds each coordinate to the chosen precision before encoding, so a round trip is accurate to roughly a metre at precision 5. That is well within GPS error for mapping use. Q: Can I decode a route from the Directions API? A: Yes. Paste the overview_polyline points string into the decoder at precision 5 and you will get the ordered list of waypoints back as lat/lon pairs. Q: Is my route data uploaded? A: No. Encoding and decoding run entirely in your browser, so your coordinates and routes are never transmitted. #### Postman Collection to OpenAPI Converter URL: https://geratools.com/postman-to-openapi Map Postman request items (method, URL, path variables, query params, headers, and JSON body) to OpenAPI 3.0 path items and operations, then download a ready-to-use openapi.yaml. Runs in-browser so API credentials in the collection stay local. How to use: 1. Provide your collection: Paste your Postman Collection v2.1 JSON into the box or load the exported .json file. It is processed locally. 2. Convert automatically: The tool walks the collection's folder and request tree and builds an OpenAPI 3.0 document with paths, parameters, and request bodies. 3. Export the spec: Review the generated YAML, then download openapi.yaml or copy it to paste into Swagger UI, Redoc, or your codegen pipeline. FAQ: Q: Which Postman export format is supported? A: Postman Collection format v2.1, the default when you export a collection from Postman. The file must contain an info object and an item array; folders are walked recursively so nested requests are included. Q: How are path variables converted? A: Postman path segments written as :id or {{id}} become OpenAPI path parameters {id}, each declared with in: path and required: true. Query parameters become optional query parameters and request headers become header parameters. Q: Does it infer a request body schema? A: Yes. For POST, PUT, and PATCH requests with a raw JSON body, the tool parses the example and infers a JSON Schema (object properties, array items, and primitive types) under requestBody with application/json content. Q: Are my API keys exposed? A: No. The entire conversion runs in your browser, including reading any file you load. Tokens, keys, and secrets stored in the collection never leave your device and are not written into the output. Q: Is the output valid OpenAPI 3.0? A: It produces a well-formed OpenAPI 3.0.3 skeleton with info, paths, parameters, request bodies, and a default 200 response. You may want to refine response schemas and descriptions, but it imports cleanly into Swagger UI and Redoc. #### Q-Encoding (RFC 2047) Encoder URL: https://geratools.com/qp-encode Encode non-ASCII email header values such as subjects and display names using RFC 2047 Q-encoding, producing =?UTF-8?Q?...?= encoded-words. Also decodes Q encoded-words back to readable text. Runs in your browser. How to use: 1. Pick a mode: Choose Encode to turn a header value into an RFC 2047 encoded-word, or Decode to read one back. 2. Enter the text: Type the header value such as an email subject with accents or emoji, or paste an existing encoded-word. 3. Copy the result: The encoded-word in the form =?UTF-8?Q?...?= is ready to drop straight into a Subject or From header. FAQ: Q: What is RFC 2047 Q-encoding? A: RFC 2047 lets non-ASCII text appear in email headers by wrapping it in an encoded-word: =?charset?Q?text?=. The Q variant is a header-specific form of quoted-printable where each non-ASCII byte becomes an equals sign followed by two hex digits, and spaces become underscores. Q: How does Q-encoding differ from quoted-printable? A: Q-encoding is based on quoted-printable but adds header-specific rules: a space is encoded as an underscore, and the characters question mark, underscore, and equals sign are always escaped because they have structural meaning inside an encoded-word. Q: When should I use Q-encoding versus B-encoding? A: Q-encoding stays mostly readable when the text is largely ASCII with a few accented characters, so it is efficient for European-language subjects. B-encoding (Base64) is more compact when most of the text is non-ASCII, such as Chinese or Arabic. Q: What is the maximum length of an encoded-word? A: RFC 2047 limits a single encoded-word to 75 characters including the charset, delimiters, and encoding marker. Longer values must be split into multiple encoded-words separated by whitespace; this tool flags when output exceeds that limit. Q: Is anything sent to a server? A: No. Encoding and decoding happen entirely in your browser with JavaScript, so email content and recipient names never leave your device. #### QR Code Decoder URL: https://geratools.com/qr-code-decoder Free QR code decoder that reads a dropped or chosen QR image entirely in your browser using the Canvas API. Decodes URL, Wi-Fi, vCard, and plain text payloads. No image is sent anywhere — privacy-first scanning. How to use: 1. Drop or choose an image: Drag a QR code image onto the box, or click to pick a PNG, JPG, or WebP file from your device. 2. Let it decode locally: The tool draws the image to a canvas, locates the finder patterns, samples the module grid, and reads the encoded data. 3. Read or copy the result: The decoded text appears with its detected type (URL, Wi-Fi, vCard, or plain text). Copy it with one click. FAQ: Q: How does QR decoding work? A: The decoder converts the image to grayscale, applies an automatic threshold (Otsu's method) to separate dark and light, finds the three corner finder patterns by their 1:1:3:1:1 ratio, samples each module of the grid, removes the data mask, and reads the bitstream into characters. Q: Is my QR image uploaded anywhere? A: No. The image is processed entirely in your browser using the HTML Canvas API. Nothing is sent to a server or third-party API, so it is safe for codes that contain Wi-Fi passwords or personal contact details. Q: What payload types are recognised? A: It decodes the raw text of any QR code and labels common formats — URLs, WIFI: network strings, BEGIN:VCARD contacts, mailto and tel links, and geo locations — so you know what kind of data the code holds. Q: Why does decoding sometimes fail? A: This decoder works best on clear, high-contrast, roughly straight-on images. Heavy blur, glare, extreme rotation, low resolution, or significant physical damage can prevent a clean read, in which case it reports an error rather than guessing. Q: Should I trust a decoded URL? A: Treat decoded links with caution. A QR code can hide a malicious URL behind an innocent-looking square. Always read the full address before opening it, especially for codes from posters, emails, or unknown sources. #### Sexagesimal (Base-60) Converter URL: https://geratools.com/sexagesimal-converter Free sexagesimal converter. Convert any integer to and from base-60 (sexagesimal) notation, the system the Babylonians used and the reason we count time and angles in 60s. Shows each base-60 digit (0–59) in standard comma-separated form. Runs entirely in your browser. How to use: 1. Choose a direction: Select whether to convert a decimal integer into sexagesimal or a sexagesimal value back into decimal. 2. Enter your value: Type a whole number, or enter base-60 digits as comma-separated groups where each group is between 0 and 59. 3. Read and copy: The converted value appears immediately with the power-of-60 breakdown explained, and you can copy it with one click. FAQ: Q: What is sexagesimal? A: Sexagesimal is a positional numeral system with base 60. Each position represents a power of 60, and each digit can range from 0 to 59. It was developed by the ancient Sumerians and Babylonians and is one of the oldest known place-value systems. Q: Why do we still use base 60 today? A: Sexagesimal survives in how we measure time — 60 seconds in a minute, 60 minutes in an hour — and in angles, where a degree has 60 arcminutes and an arcminute has 60 arcseconds. We inherited these divisions directly from Babylonian astronomy. Q: How are sexagesimal numbers written? A: Because base 60 needs 60 distinct digits, scholars write each digit as an ordinary decimal number and separate the positions with commas. So 1,1,1 means one 3600 plus one 60 plus one, which is 3661 in decimal. Q: Why must each group be less than 60? A: Each position in a base-60 number is a single digit that can only hold values 0 through 59, just as each decimal position holds 0 through 9. A group of 60 or more would overflow into the next position, so the converter rejects it as invalid. Q: What is a good example to understand it? A: The number of seconds in an hour, 3600, is exactly 1,0,0 in sexagesimal — one unit of 3600 and nothing else. Add one minute and one second and you get 3661, which is 1,1,1. This mirrors how a clock reads hours, minutes and seconds. #### Shift-JIS Encoder/Decoder URL: https://geratools.com/shift-jis-encode Encode Japanese text to Shift-JIS (CP932) byte sequences shown as hex, or decode Shift-JIS hex bytes back to text. Handles single-byte ASCII and half-width katakana plus two-byte kanji, runs locally in your browser, and flags characters outside the repertoire. How to use: 1. Pick a direction: Choose whether to encode Japanese text into Shift-JIS hex bytes, or decode Shift-JIS hex bytes back into text. 2. Enter your input: For encoding, paste Japanese text. For decoding, enter the bytes as space- or comma-separated hex values. 3. Copy the result: The output updates instantly; click copy to put it on your clipboard. Characters that Shift-JIS cannot store are flagged. FAQ: Q: What is Shift-JIS? A: Shift-JIS is a widely used Japanese character encoding. The Windows variant, CP932, is what most files and systems mean by Shift-JIS. It mixes single-byte and two-byte characters in one stream, which is why it needs lead and trail byte ranges. Q: How many bytes does a character take? A: ASCII and half-width katakana are one byte. Kanji, hiragana, full-width katakana, and full-width symbols are two bytes: a lead byte in 0x81 to 0x9F or 0xE0 to 0xFC, followed by a trail byte in 0x40 to 0xFC excluding 0x7F. Q: Why might a character be unmapped? A: Shift-JIS covers the JIS X 0208 repertoire plus extensions, not all of Unicode. Characters such as many emoji, rare kanji outside the set, or non-Japanese scripts have no Shift-JIS bytes and are marked with ?? when encoding. Q: Is this the same as EUC-JP or ISO-2022-JP? A: No. Those are other Japanese encodings of the same characters but with different byte layouts. The same kanji has different bytes in Shift-JIS, EUC-JP, and ISO-2022-JP, so always keep the encoding name with the bytes. Q: Does my text leave the browser? A: No. The encoding table is built in your browser from the native decoder and applied locally in both directions. Nothing is uploaded to a server. #### Soundex Encoder URL: https://geratools.com/soundex-encode Free Soundex encoder using the classic US Census / NARA algorithm. Turn any name into its 4-character phonetic code for fuzzy matching and indexing. Runs in your browser. How to use: 1. Enter a name: Type a surname, given name, or word into the input field. 2. Read the code: The 4-character Soundex code appears instantly — a letter followed by three digits. 3. Compare names: Enter similar-sounding names and check whether they share a code to confirm a phonetic match. FAQ: Q: What is a Soundex code? A: It is a 4-character code (one letter plus three digits) that represents how a name sounds rather than how it is spelled. Names that sound alike usually get the same code, which makes it useful for fuzzy matching. Q: Which Soundex variant does this use? A: It implements American Soundex as defined by the US Census Bureau and the National Archives (NARA), including the H/W transparency rule and vowel separator handling. Q: Why do Robert and Rupert give the same code? A: Both encode to R163. Soundex keeps the first letter and codes B/P/F/V as 1 and R/T as 6, so the differing vowels and the B-vs-P distinction are deliberately ignored. Q: Is Soundex case sensitive? A: No. The encoder uppercases the input and strips non-letters first, so "O'Brien" and "obrien" produce the same result. Q: What are the limits of Soundex? A: It was designed for English surnames and is fairly coarse. Metaphone or NYSIIS are usually more accurate, and none of them handle non-English names well. #### Tab ↔ Space Converter URL: https://geratools.com/tab-space-convert Convert between tab characters and configurable-width space indentation. Expands tabs using true tab-stop rules and re-tabs leading indentation, so source-code alignment stays intact. Runs entirely in your browser. How to use: 1. Choose a direction: Pick whether to expand tabs into spaces or compress leading spaces back into tabs. 2. Set the tab width: Enter how many columns one tab advances, typically 2, 4, or 8 to match your editor settings. 3. Paste and convert: Paste your code or text and read the converted result, then copy it back to your editor. FAQ: Q: Why does tab expansion sometimes add fewer spaces than the width? A: A tab advances to the next tab stop, not a fixed number of spaces. If the cursor is already partway into a tab column, only the spaces needed to reach the next multiple of the width are added. This matches how editors and terminals render tabs. Q: Does spaces-to-tabs change spaces inside a line? A: No. Only the leading indentation of each line is re-tabbed. Alignment spaces inside a line, such as those lining up the right-hand side of an assignment, are preserved so your code formatting is not corrupted. Q: Which should I use, tabs or spaces? A: It depends on your project's style guide. Python's PEP 8 and many JavaScript styles prefer spaces; Go and the Linux kernel use tabs. The safest rule is to match whatever the existing file already uses. Q: Will this break a mix of tabs and spaces? A: The spaces-to-tabs direction first normalises any tabs already in the indent to spaces using your chosen width, then re-tabs cleanly. This produces consistent indentation even from messy mixed input. Q: Is anything uploaded? A: No. The conversion is plain string processing that runs locally in your browser. Your code never leaves the page. #### Timezone Offset Converter URL: https://geratools.com/timezone-offset-converter Free timezone offset converter. Enter a date and time at one UTC offset and instantly see the equivalent local time at any other offset, with the shared UTC instant shown for reference. Runs entirely in your browser. How to use: 1. Enter the source time: Type the date and time you have, then choose the UTC offset it belongs to. 2. Choose the target offset: Select the UTC offset you want to convert the time into. 3. Read the converted time: The equivalent local date-time appears instantly, along with the shared UTC instant for reference. FAQ: Q: How does converting between offsets work? A: Every wall-clock time corresponds to one absolute instant in UTC. The tool subtracts the source offset to get UTC, then adds the target offset to get the destination time. Conversion is just arithmetic on minutes. Q: Why does the date sometimes change? A: When the offset difference pushes a time past midnight, the calendar date rolls forward or backward. For example, 11 PM at UTC+9 is 2 PM the same day at UTC+0, but 6 AM the next day at UTC+12 may land on a different date. Q: Does this handle daylight saving time? A: No. This tool works with fixed numeric UTC offsets, not named zones. If a region is observing DST, pick the offset it is currently using (for example UTC-4 instead of UTC-5 for US Eastern in summer). Q: What offsets are supported? A: Any offset from UTC-12:00 to UTC+14:00, including half-hour and 45-minute offsets such as +05:30 (India) and +05:45 (Nepal). You select offsets directly so there is no ambiguity from named zones. Q: Is my data sent anywhere? A: No. All conversion happens in your browser using local date arithmetic. Nothing is uploaded, stored, or logged. #### TLS Cipher Suite Decoder URL: https://geratools.com/tls-cipher-suite-decoder Decode any TLS cipher suite by IANA name (TLS_AES_128_GCM_SHA256) or hex code (0x1301), break out the key exchange, bulk cipher and MAC, and rate it against current BSI and NIST guidance. RC4, MD5, 3DES, export-grade and anonymous suites are flagged as weak or insecure. How to use: 1. Enter the suite: Paste an IANA cipher suite name beginning with TLS_, or its two-byte hex code such as 0x1301. 2. Read the breakdown: The tool splits the suite into key exchange, authentication, bulk cipher, and MAC components. 3. Check the rating: A secure, weak, or insecure rating is shown with the specific reasons, so you know whether to keep or drop the suite. FAQ: Q: How is the security rating decided? A: The tool inspects each component of the suite. NULL ciphers, RC4, MD5, export-grade and anonymous key exchange are marked insecure. 3DES and CBC modes on TLS 1.2 are marked weak. Modern AEAD ciphers such as AES-GCM and ChaCha20-Poly1305 with ephemeral key exchange are marked secure. Q: What is forward secrecy and why does it matter? A: Forward secrecy means a compromise of the server's long-term private key cannot decrypt past recorded sessions. It comes from ephemeral key exchange (ECDHE or DHE). Static RSA or DH suites lack it, which is why they are flagged even when the cipher itself is strong. Q: Why are TLS 1.3 suites shown without an explicit key exchange? A: In TLS 1.3 the cipher suite only names the AEAD cipher and hash. Key exchange and authentication are negotiated separately through other extensions, always using ephemeral key exchange, so every TLS 1.3 suite has forward secrecy by design. Q: What is the difference between AEAD and CBC ciphers? A: AEAD ciphers such as AES-GCM and ChaCha20-Poly1305 combine encryption and integrity in one operation and resist padding-oracle attacks. CBC mode in TLS 1.2 separates encryption from a MAC and has a history of padding-oracle issues, so AEAD is preferred. Q: Is anything sent to a server? A: No. The decoding and rating run entirely in your browser against a bundled subset of the IANA registry. Nothing you enter is transmitted. #### Homoglyph Steganography Encoder URL: https://geratools.com/unicode-stego-homoglyph Hide a secret message in ordinary-looking text by swapping Latin letters for visually identical Cyrillic homoglyphs to carry binary data. Decode any homoglyph-laced text back to the hidden message. How to use: 1. Enter cover text and secret: Provide cover text containing swappable letters (a, c, e, o, p, x, y and their capitals) plus the secret message to embed. 2. Encode: The tool converts the secret to bits and walks the cover; at each swappable letter a 1-bit swaps in a Cyrillic homoglyph and a 0-bit leaves the Latin letter, so the text looks unchanged. 3. Decode later: Paste the homoglyph-laced text into decode mode; the tool reads each swappable position as a bit and reconstructs the hidden message. FAQ: Q: What is a homoglyph? A: A homoglyph is a character that looks identical or nearly identical to another but has a different Unicode code point. Latin 'a' (U+0061) and Cyrillic 'а' (U+0430) are a classic pair — indistinguishable on screen, distinct to a computer. Q: How does the message get hidden? A: The secret is turned into bits. Walking through the cover text, each letter that has a Cyrillic lookalike carries one bit: a 1 substitutes the Cyrillic homoglyph, a 0 keeps the Latin original. The reader sees the same words either way. Q: How much can I hide? A: One bit per swappable letter, and one secret character needs 8 bits. So you need cover text with at least 8 swappable letters (a, c, e, o, p, x, y and capitals A, C, E, O, P, X, Y) for every character of the secret. Q: Is the hidden data secure? A: No. This is concealment, not encryption. Anyone who compares the code points or knows the scheme can recover the bits, so encrypt the secret first if you need real confidentiality. Q: Why might decoding give the wrong result? A: If the text passed through a system that normalised confusable characters or auto-corrected the Cyrillic letters back to Latin, the bits are lost. Some search and spell-check tools do this, so verify your channel preserves the exact code points. #### Current Unix Timestamp URL: https://geratools.com/unix-now See the current Unix timestamp live in seconds, milliseconds, microseconds, and nanoseconds, with the matching UTC ISO time. Each value updates many times per second and is one click to copy. How to use: 1. Open the tool: The current Unix timestamp starts ticking automatically as soon as the page loads. 2. Pick the precision you need: Read the timestamp in seconds, milliseconds, microseconds, or nanoseconds from the live rows. 3. Copy a value: Click Copy next to any row to put that timestamp on your clipboard. FAQ: Q: What is a Unix timestamp? A: It is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, known as the Unix epoch. It is a timezone-independent way to represent a moment in time as a single number. Q: How are milliseconds, microseconds, and nanoseconds derived? A: Browsers expose time at millisecond precision. Seconds are the millisecond value divided by 1000 and floored, while microseconds and nanoseconds are the millisecond value scaled up by 1,000 and 1,000,000. Q: Are the microsecond and nanosecond digits real precision? A: No. Because the browser clock only resolves to milliseconds, the extra digits are zero-filled. They are convenient when a system expects those units but should not be read as sub-millisecond accuracy. Q: Is the timestamp in my local timezone? A: No. Unix time is always counted from the UTC epoch, so it is the same instant everywhere. The ISO line at the bottom shows that instant formatted in UTC for reference. Q: How often does it update? A: The display refreshes roughly twenty times a second, so the milliseconds and finer values tick visibly while the page is open. #### Unix Timestamp (Microseconds) Converter URL: https://geratools.com/unix-timestamp-microseconds Free Unix timestamp converter for microseconds since the epoch. Convert a 16-digit microsecond timestamp to an ISO-8601 date-time with sub-second precision, and convert a date-time back to epoch microseconds. Runs entirely in your browser. How to use: 1. Enter a microsecond timestamp: Paste a value in microseconds since 1970-01-01 (e.g. 1700000000000000) to decode it. 2. Or enter a date-time: Type an ISO-8601 date-time in the reverse field to compute its epoch microseconds. 3. Read the result: The tool shows the date-time with full sub-second precision and the raw microsecond value for copying. FAQ: Q: What is a microsecond Unix timestamp? A: It is the number of microseconds (millionths of a second) since 1970-01-01T00:00:00Z. A present-day value is about 16 digits long and is common in databases like PostgreSQL and in high-resolution logging. Q: How does this handle large numbers safely? A: Microsecond timestamps can exceed JavaScript's safe integer limit, so this tool uses BigInt to split the value into whole milliseconds plus a microsecond remainder, keeping precision exact. Q: How is it different from milliseconds? A: A microsecond value is 1000 times larger than the same instant in milliseconds (about 16 digits versus 13). Divide by 1000 to get milliseconds, or by 1,000,000 to get seconds. Q: Will I lose the sub-millisecond digits? A: No. The tool preserves the microsecond remainder and appends it to the ISO-8601 fractional seconds, so the last three digits are not discarded. Q: Is my data sent anywhere? A: No. Everything is computed locally in your browser using BigInt and the Date API. Nothing is uploaded. #### UPC-E to UPC-A Expander URL: https://geratools.com/upc-e-to-upc-a Expand a zero-suppressed UPC-E barcode into its full 12-digit UPC-A equivalent using the official GS1 reconstruction rules, then recompute and verify the modulo-10 check digit. Accepts 6, 7, or 8-digit UPC-E input. Runs entirely in your browser. How to use: 1. Enter the UPC-E code: Type the 6-digit body, the 7-digit form with a leading 0, or the full 8-digit UPC-E including its check digit. 2. Let the tool reconstruct: The expander reads the final body digit to decide where the suppressed zeros belong and rebuilds the 11-digit UPC-A data section. 3. Read and verify: See the full 12-digit UPC-A with its recomputed modulo-10 check digit, and if you supplied a check digit the tool verifies it matches. FAQ: Q: What is UPC-E? A: UPC-E is a compact 8-digit barcode that encodes a UPC-A whose 12-digit number contains runs of zeros. Suppressing those zeros lets the code fit on small packages like cans and cosmetics. Q: How does the expansion decide where zeros go? A: The last digit of the 6-digit body acts as a key. Values 0 to 2 expand one way, 3 expands another, 4 another, and 5 to 9 a fifth way, each reinserting a specific pattern of zeros into the manufacturer and product fields. Q: Why is the check digit recomputed? A: The UPC-A check digit is a modulo-10 checksum over the first 11 digits, with odd positions weighted by 3. Because expansion changes the digit string, the tool recalculates it so the resulting UPC-A is valid. Q: Can I enter the full 8-digit UPC-E? A: Yes. If you include the leading number-system 0 and the trailing check digit, the tool extracts the 6-digit body, expands it, and confirms whether the check digit you supplied matches the one it computes. Q: Does this work for number system 1? A: UPC-E expansion is defined only for number system 0 (and the rarely used 1, which shares the table). This tool assumes number system 0, which covers virtually all retail UPC-E barcodes you will encounter. #### UUencode Encoder/Decoder URL: https://geratools.com/uuencode-encoder Encode text into the classic UNIX uuencode format with begin/end framing, or decode a uuencoded block back to plain text. Implements the real 3-byte-to-4-character algorithm with per-line length bytes. Free, browser-based, instant. How to use: 1. Pick encode or decode: Choose Encode to wrap plain text in a uuencode block, or Decode to extract the original bytes from a block. 2. Set a filename (encoding): When encoding, enter the filename you want written into the begin header line; it defaults to message.txt. 3. Run and copy: Paste your text or uuencode block, read the result below, and click Copy to save it. FAQ: Q: What is uuencode? A: uuencode is a UNIX utility from the 1980s that turns binary files into printable ASCII so they can pass through email and Usenet. The encoded data is framed by a begin line with permissions and filename, and an end line. Q: How does the line format work? A: Each data line starts with a length character giving how many bytes that line encodes, followed by groups of four characters. Every group of four characters represents three original bytes using 6-bit values offset by 0x20. Q: What is the back-tick at the end? A: A length of zero is written as the back-tick character (0x60) rather than a space, signalling the final data line. This is the modern convention that avoids trailing-space stripping problems. Q: Is uuencode the same as Base64? A: Both map 3 bytes to 4 characters, but uuencode uses values offset by 0x20 across a contiguous ASCII range and adds per-line length bytes plus begin/end framing. Base64 uses a fixed 64-character alphabet and padding. Q: Can it decode files made by the real uuencode command? A: Yes. The decoder ignores the begin and end lines, reads the leading length byte on each line, and stops at the zero-length terminator, matching standard uudecode behaviour for text payloads. #### vCard to LDIF Converter URL: https://geratools.com/vcf-to-ldif Free vCard to LDIF converter. Turn .vcf contacts into LDIF entries with cn, sn, mail, telephoneNumber and inetOrgPerson object classes, ready for ldapadd into OpenLDAP or Active Directory. Runs entirely in your browser. How to use: 1. Provide your vCards: Paste vCard text or load a .vcf file exported from your phone, Google Contacts, Outlook or any address book. 2. Set the base DN: Enter the directory branch where the entries should live, for example ou=people,dc=example,dc=com. The cn becomes the RDN of each entry. 3. Copy or download the LDIF: Copy the generated LDIF or download a .ldif file, then import it with ldapadd or your directory's import tool. FAQ: Q: What is LDIF? A: LDIF (LDAP Data Interchange Format) is the standard plain-text format for representing directory entries and changes. Tools like ldapadd and Active Directory's ldifde read LDIF to create users and objects in bulk, making it the usual way to import many contacts at once. Q: Which vCard fields are mapped? A: FN becomes cn, N becomes sn and givenName, EMAIL becomes mail, TEL becomes telephoneNumber or mobile depending on the TYPE, ORG becomes o and ou, TITLE becomes title, ADR becomes street, l, st and postalCode, URL becomes labeledURI, and NOTE becomes description. Q: What object classes are used? A: Each entry is created with top, person, organizationalPerson and inetOrgPerson, which is the standard schema for representing people in OpenLDAP and most directories. inetOrgPerson provides mail, mobile, title and the other common contact attributes. Q: Why are some values shown with a double colon? A: LDIF requires base64 encoding for any value containing non-ASCII characters, a leading space or certain special characters. Those lines use the attr:: base64 form, which ldapadd decodes automatically, so accented names and addresses import correctly. Q: Is my contact data uploaded? A: No. Parsing and conversion happen entirely in your browser with JavaScript. Your contacts never leave your device, so it is safe to convert a full personal or corporate address book. #### Whitespace Steganography Encoder URL: https://geratools.com/whitespace-stego Hide a secret message inside invisible trailing whitespace, encoding each byte as a pattern of spaces (bit 0) and tabs (bit 1). Decode any whitespace-tagged text back to the hidden message. How to use: 1. Enter cover text and a secret: Type the visible cover text and the secret message you want to hide inside it. 2. Encode: The tool converts your secret to bits, maps each bit to a space (0) or tab (1), and appends that invisible whitespace block to the cover text. 3. Decode later: Paste any whitespace-tagged text into decode mode to read the spaces and tabs back into the original hidden message. FAQ: Q: How does whitespace steganography work? A: Each character of the secret message is turned into 8 bits. A bit value of 0 is written as a space and a bit value of 1 as a tab. These whitespace characters are appended to the cover text where they are invisible in most editors. Q: Why use spaces and tabs instead of zero-width characters? A: Spaces and tabs are ordinary ASCII whitespace that survives copy-paste through plain-text channels, code comments and many chat apps where exotic Unicode might be stripped. They are invisible at the end of a line. Q: Is the hidden data encrypted? A: No. Steganography hides the existence of a message, it does not encrypt it. Anyone who knows the space/tab scheme can decode it, so combine it with real encryption if you need secrecy rather than just concealment. Q: Will the whitespace survive everywhere? A: Often, but not always. Many editors, linters and chat platforms trim trailing whitespace automatically, which would destroy the hidden payload. Test your channel before relying on it. Q: What characters can I hide? A: This encoder uses 8 bits per character, covering standard ASCII. For full Unicode, encode your secret as UTF-8 first; the tool handles each code unit up to 8 bits and warns if a character is out of range. #### Windows FILETIME Converter URL: https://geratools.com/windows-filetime-converter Convert a Windows FILETIME value to a UTC date and back. FILETIME counts 100-nanosecond intervals since 1601-01-01, and the tool accepts decimal or hex input using exact BigInt arithmetic and shows the matching Unix timestamp. How to use: 1. Choose the direction: Pick FILETIME to date if you have a 64-bit value, or date to FILETIME if you have a UTC date and time. 2. Enter the value: Paste a FILETIME as a decimal integer or a 0x-prefixed hex string, or type an ISO-8601 UTC date. 3. Read the result: The tool returns the UTC date with the Unix timestamp, or the FILETIME value with its hex form. FAQ: Q: What is a Windows FILETIME? A: FILETIME is a 64-bit value that counts the number of 100-nanosecond intervals since midnight on 1 January 1601 in UTC. Windows uses it for file timestamps and many system APIs. Q: How does FILETIME relate to Unix time? A: The Unix epoch of 1 January 1970 is 116,444,736,000,000,000 intervals after the FILETIME epoch. The tool subtracts that constant to convert to a normal date and a Unix timestamp. Q: Can I enter the value in hexadecimal? A: Yes. Prefix the value with 0x to enter it as hexadecimal, which is how FILETIME often appears in registry dumps, memory, and forensic tools. Plain decimal input is also accepted. Q: Why use BigInt arithmetic? A: A FILETIME spans the full unsigned 64-bit range, which is larger than a JavaScript number can hold exactly. BigInt keeps every digit precise so the conversion is not silently rounded. Q: What date range does it cover? A: Values must fit in an unsigned 64-bit integer. The epoch is 1601-01-01, and the maximum value reaches the year 30828, far beyond any practical timestamp you will encounter. #### WOFF2 to TTF Converter URL: https://geratools.com/woff2-to-ttf Free WOFF2 to TTF converter. Parses the WOFF2 header, decompresses the Brotli table stream with the browser's native DecompressionStream, reconstructs the SFNT, and downloads the result. Runs fully in your browser — the font is never uploaded. How to use: 1. Choose a WOFF2 file: Pick or drop a .woff2 web font. The bytes are read locally — nothing is uploaded. 2. Convert: The tool decompresses the Brotli-packed table directory, rebuilds the SFNT table structure, and assembles a TrueType/OpenType binary. 3. Download the TTF: Save the reconstructed font and install it, or open it in a font editor for desktop use. FAQ: Q: Why convert WOFF2 back to TTF? A: WOFF2 is a web-only wrapper around a TrueType or OpenType font, compressed with Brotli. Desktop apps, font editors, and operating-system installers expect a raw TTF or OTF, so you often need to unwrap a web font for local use. Q: Is the font uploaded to a server? A: No. The file is read with FileReader and decompressed with the browser's built-in DecompressionStream. The conversion happens entirely on your device and nothing is transmitted. Q: Why might conversion fail in my browser? A: WOFF2 tables are Brotli-compressed. Most modern browsers expose Brotli through the native DecompressionStream API, but a few older builds do not. If your browser lacks native Brotli support the tool will tell you, and you can retry in an up-to-date Chrome, Edge, or Firefox. Q: Does the output keep all glyphs and OpenType features? A: Yes — decompression is lossless. Every glyph, kerning pair, and OpenType layout table the WOFF2 contained is restored bit-for-bit into the SFNT output, except that WOFF2's optional glyf transform is reversed during reconstruction. Q: Will the converted file be a .ttf or .otf? A: It matches the original. If the WOFF2 wrapped a TrueType outline font the output is a TTF; if it wrapped a CFF (PostScript) font the signature is OTTO and you should save it as .otf. #### XXEncode / XXDecode URL: https://geratools.com/xxencode Free xxencode and xxdecode tool. Encodes binary data with the punctuation-free XX alphabet (digits, letters, plus and minus) that survives strict mail gateways, using the same begin header and length-prefixed lines as uuencode. Client-side. How to use: 1. Choose encode or decode: Pick encode to turn text into an xxencoded block, or decode to convert an xxencoded block back to text. 2. Set the file name when encoding: The name and octal mode 644 are written into the begin header just like uuencode, so xxdecode can recreate the file. 3. Copy your result: The encoded block or decoded text appears below with a copy button. FAQ: Q: How is xxencode different from uuencode? A: They share the same structure (begin header, lines of up to 45 bytes packed 3-into-4, end trailer) but use different alphabets. UUEncode maps 6-bit values onto a range that includes many punctuation marks, while xxencode uses only plus, minus, digits and letters. Q: Why prefer the XX alphabet? A: Some early mail and EBCDIC gateways rewrote or stripped punctuation characters, which silently corrupted uuencoded blocks. The XX alphabet avoids all punctuation except plus and minus, so the encoded data passed through those gateways intact. Q: What is the line-length character? A: Each data line begins with one alphabet character whose value is the number of original bytes that line represents, from 1 to 45. The decoder reads it to know how many bytes to emit, which is how trailing padding is discarded correctly. Q: Can xxencode handle binary, not just text? A: Yes, the algorithm encodes raw bytes. This tool treats your input as UTF-8 text for convenience, but the same 3-byte-to-4-character packing works on any byte stream. Q: Is anything uploaded? A: No. Encoding and decoding run entirely in your browser. No data is sent to a server. #### yEnc Encoder/Decoder URL: https://geratools.com/yenc-encode Free yEnc encoder and decoder implementing the offset-42 byte shift, critical-character escaping and CRC32 integrity check used for Usenet binaries. Encode text to a =ybegin/=yend block or decode one and verify its CRC, client-side. How to use: 1. Choose encode or decode: Pick encode to turn text into a yEnc block, or decode to read a yEnc article body back into the original bytes. 2. Provide the data: When encoding, enter the file name for the =ybegin line and the text. When decoding, paste the block from =ybegin to =yend. 3. Check the CRC on decode: The decoder recomputes the CRC32 of the recovered bytes and shows whether it matches the value in the =yend trailer. FAQ: Q: Why is yEnc more efficient than uuencode? A: UUEncode always expands data by about 35% because it re-encodes every byte. yEnc instead adds 42 to each byte and leaves it as a single character, escaping only the handful of bytes that would break a Usenet article. Most bytes stay one byte, so overhead is typically only 1 to 2%. Q: What does the byte shift do? A: Each source byte is mapped to (byte + 42) mod 256. This moves common values away from the control characters that newsreaders interpret. Decoding simply subtracts 42 (mod 256) from each character to recover the original byte. Q: Which characters are escaped? A: After the shift, null, line feed, carriage return and the equals sign are escaped because they would terminate or corrupt a line. An escaped byte is written as an equals sign followed by the byte plus 64 (mod 256). A leading dot is also escaped to survive SMTP dot-stuffing. Q: What is the crc32 in the =yend line? A: It is a CRC32 checksum of the original unencoded bytes. After decoding, a reader recomputes the CRC32 and compares it to the trailer value. A mismatch means the article was truncated or corrupted in transit. This tool performs that check for you. Q: Is my data uploaded? A: No. The byte shift, escaping and CRC32 all run locally in your browser. Nothing leaves your device. #### Z85 Encoder/Decoder URL: https://geratools.com/z85-encode Encode and decode Z85, the ZeroMQ RFC 32 flavour of Base85 whose 85-character alphabet is chosen to drop safely into source-code string literals. Packs four bytes into five characters, auto-pads text input, and round-trips entirely in your browser. How to use: 1. Choose encode or decode: Pick Encode to turn text into a Z85 string, or Decode to turn a Z85 string back into the original bytes. 2. Enter your data: Paste the text to encode or the Z85 string to decode. Text input is auto-padded to a four-byte boundary. 3. Read and copy the result: The result appears instantly. Decodes that are not valid UTF-8 fall back to a hex view. FAQ: Q: How does Z85 differ from Adobe Ascii85? A: Both pack four bytes into five characters, but they use different alphabets. Z85 (ZeroMQ RFC 32) deliberately avoids characters like backslash, single quote, and double quote so the output can be embedded directly inside source-code string literals without escaping. Ascii85 makes no such guarantee and uses a different symbol set. Q: Why must Z85 input be a multiple of four or five? A: Z85 has no padding scheme, so by specification the byte length must be a multiple of four and the encoded length a multiple of five. This tool auto-pads text input with zero bytes when encoding, but a Z85 string you decode must already have a length that is a multiple of five. Q: What is Z85 commonly used for? A: It was introduced by ZeroMQ to encode the 32-byte CurveZMQ public and private keys into compact 40-character strings that are convenient to copy into configuration files and source code. Any fixed-length binary key fits this use well. Q: Why was my text padded with zero bytes? A: Z85 cannot encode a byte count that is not a multiple of four, and unlike some encodings it has no padding marker. To let you encode arbitrary text anyway, the tool appends the minimum number of zero bytes to reach a four-byte boundary and tells you how many it added. Q: Is anything sent to a server? A: No. Encoding and decoding happen entirely in your browser, so keys and other sensitive binary stay on your device. #### Case Converter URL: https://geratools.com/case-converter Free case converter that turns any text into camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Title Case and Sentence case at once. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your text: Type or paste the words, identifier or phrase you want to convert. 2. Read every case at once: camelCase, PascalCase, snake_case, kebab-case, Title Case and more appear instantly. 3. Copy the one you need: Click Copy next to any result to put it on your clipboard. FAQ: Q: Which cases are supported? A: camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Title Case, Sentence case, lower case and UPPER CASE — all generated at once from the same input. Q: Can it convert existing camelCase or snake_case input? A: Yes. The converter splits on spaces, punctuation, underscores, hyphens and camelCase boundaries, so you can paste an identifier in any style and reformat it. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser with JavaScript — nothing is sent to a server and nothing is stored. Q: What is the difference between camelCase and PascalCase? A: Both join words with no separator and capitalise each word, but camelCase keeps the first word lowercase (e.g. userName) while PascalCase capitalises it too (e.g. UserName). camelCase is common for variables and functions; PascalCase for classes, types and React components. Q: When should I use snake_case versus kebab-case? A: snake_case (words joined by underscores) is the convention for Python, Ruby and database column names. kebab-case (words joined by hyphens) is used for URLs, CSS class names and HTML attributes. CONSTANT_CASE is reserved for fixed values like environment variables. Q: How does Title Case differ from Sentence case? A: Title Case capitalises the first letter of every word (Convert Your Text Now). Sentence case capitalises only the first letter of the whole string (Convert your text now). This tool produces both at once so you can pick the right one for a heading versus body copy. Q: Will it fix an all-caps phrase typed by accident? A: Yes. Paste a sentence that is stuck in CAPS LOCK and the Sentence case, lower case and Title Case outputs all give you a corrected version instantly, ready to copy back. #### Unix Timestamp Converter URL: https://geratools.com/unix-timestamp-converter Free Unix timestamp converter. Turn epoch seconds or milliseconds into human-readable UTC, local, and ISO 8601 dates with a relative ("3 hours ago") label, and convert any date back to a timestamp. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your timestamp: Enter a Unix epoch value and choose whether it is in seconds or milliseconds. 2. Read the decoded dates: The converter shows the UTC time, your local time, the ISO 8601 string, and a relative label such as "in 2 days". 3. Convert a date back: Use the date picker to convert any calendar date and time back into epoch seconds and milliseconds. FAQ: Q: Is my timestamp sent anywhere? A: No. The conversion happens entirely in your browser using the built-in JavaScript Date object. Nothing is uploaded to any server. Q: What is the difference between seconds and milliseconds? A: Unix time is most often counted in seconds since 1 January 1970 UTC, but JavaScript and many APIs use milliseconds (1000× larger). Use the dropdown to tell the converter which unit your number is in. Q: Why does my local time differ from UTC? A: UTC is the global reference time with no offset, while local time is shifted by your time zone and daylight saving. The tool shows both so you can compare them directly. Q: What is a Unix timestamp? A: It is the number of seconds (or milliseconds) that have elapsed since the Unix epoch, midnight UTC on 1 January 1970, ignoring leap seconds. It is the standard way computers store an instant in time independent of time zone. Q: How do I tell if a number is in seconds or milliseconds? A: A present-day timestamp in seconds is about 10 digits (around 1.7 billion), while the same instant in milliseconds is about 13 digits. Pick the matching mode, or as a rule of thumb a 13-digit value is almost always milliseconds. Q: What is the year 2038 problem? A: Systems that store Unix time in a signed 32-bit integer overflow on 19 January 2038, when the value exceeds 2,147,483,647 seconds. Modern systems use 64-bit timestamps, which push the limit hundreds of billions of years into the future. Q: Does the timestamp 0 mean anything special? A: Yes — Unix timestamp 0 is exactly the epoch: 00:00:00 UTC on 1 January 1970. Negative values represent dates before 1970. Q: Why do I see 1 January 1970 when I expected a recent date? A: That usually means a milliseconds value was read as seconds (or a value of 0 or null was passed). A small number of seconds since the epoch lands in early 1970, so check that you selected the right unit. #### Snake Case to Camel Case Converter URL: https://geratools.com/snake-to-camel-case Free snake_case to camelCase converter for developers. Paste underscore-separated identifiers and get camelCase output instantly, even from messy mixed input. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your snake_case text: Type or paste underscore-separated identifiers such as 'my_variable_name' into the input box. 2. Read the camelCase output: The camelCase result updates instantly as you type. 3. Copy the result: Click Copy to put the camelCase string on your clipboard. FAQ: Q: What is snake_case? A: Snake_case writes compound words in lowercase separated by underscores, like 'my_variable_name'. It is the conventional naming style in Python, Ruby, Rust, and SQL/database column names. Q: How does it convert to camelCase? A: The input is split on every run of non-alphanumeric characters into lowercase word tokens. The first word is left lowercase and the first letter of each following word is capitalised, then the words are joined with no separators. Q: What is the difference between camelCase and PascalCase? A: camelCase keeps the first word lowercase (myVariableName), while PascalCase capitalises the first word too (MyVariableName). This tool produces camelCase. Q: Does it handle spaces, dashes, or double underscores? A: Yes. Any run of non-alphanumeric characters — underscores, spaces, hyphens, or several together — is treated as a single word boundary, so messy input like 'order__total amount' still converts cleanly. Q: How are numbers treated? A: Digits are kept and count as part of a word. 'http_2_client' becomes 'http2Client', because the splitter only breaks on non-alphanumeric characters. Q: Is my text uploaded anywhere? A: No — the conversion happens entirely in your browser and nothing is sent over the network. #### Batch Timestamp Converter URL: https://geratools.com/batch-timestamp-converter Paste many Unix epoch timestamps or dates and convert them all in one pass. Auto-detects seconds vs milliseconds, shows ISO 8601, UTC, your time zone, the offset and a relative label, and exports to CSV or JSON. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your timestamps: Drop one value per line into the input box. Each line can be epoch seconds, epoch milliseconds, an ISO 8601 string, or any date your browser can parse. 2. Choose how numbers are read: Leave it on Auto-detect to let the tool tell seconds from milliseconds by digit count, or force Seconds or Milliseconds when your data is mixed or ambiguous. 3. Pick an output time zone: Select UTC, your own zone, or any IANA zone such as Asia/Tokyo. Every row is re-rendered in that zone with the correct daylight-saving offset. 4. Copy or export the results: Click any cell to copy a single value, or use Copy/Download CSV and JSON to take the whole converted table into a spreadsheet or script. FAQ: Q: How does it tell epoch seconds from milliseconds? A: In Auto-detect mode it looks at the magnitude of each number. A value of about a trillion (10^12) or more is treated as milliseconds, because that many seconds would be a date tens of thousands of years in the future. Smaller integers are treated as seconds. If your data is unusual you can override this with the Seconds or Milliseconds setting, which is applied to every numeric line. Q: Can I mix timestamps and human dates in the same list? A: Yes. Each line is parsed independently. Plain integers are read as epoch values, decimals like 1700000000.5 are read as fractional seconds, and anything else is handed to the browser date parser, so ISO 8601 strings, "2026-12-25 18:30:00" and "Jan 1 2030" all work side by side. Q: Is the conversion timezone-aware and does it handle daylight saving? A: It is. The output column is rendered through the Intl time-zone database built into your browser, so each row uses the correct UTC offset for its own instant — a July timestamp and a January timestamp in the same zone will show different offsets if that zone observes daylight saving. Q: What does the relative column mean? A: It shows how far each instant is from the current time, such as "3 hours ago" or "in 2 days". The clock updates every second, so a row that says "in 1 minute" will roll over to "1 minute ago" as real time passes. Q: What formats can I export? A: You can copy or download a CSV with columns for the original input, epoch seconds, epoch milliseconds, ISO 8601 UTC, UTC wall-clock, your chosen zone, the offset and the relative label. The same data is available as a JSON array of objects for piping into scripts. Q: Is my data sent anywhere? A: No. All parsing, time-zone math and exporting happen locally in your browser using standard web APIs. Your list is auto-saved in this browser so it survives a refresh, but it never leaves your device. #### Number Base Converter URL: https://geratools.com/number-base-converter Free online number base converter with live cross-fill. Convert between binary, octal, decimal, hexadecimal and any arbitrary base from 2 to 36, with BigInt precision, bit stats and a saved history. Runs entirely in your browser. How to use: 1. Type a number into any base field: Enter a value in the binary, octal, decimal, hex or any custom base row — every other base fills in instantly as you type. 2. Add or remove bases: Click a named base chip to show or hide its row, or type any radix from 2 to 36 in the custom box and add it. 3. Copy or save the result: Use the Copy button on any row to grab a clean value, or star the current number to keep it in your history for later. FAQ: Q: How do I convert binary to decimal? A: Type your binary digits into the Base 2 row and the Base 10 row updates instantly. For example 11111111 in binary becomes 255 in decimal. The converter also shows the same value in octal, hex and any other base you have enabled. Q: What is the largest number this base converter supports? A: There is no practical limit. The tool uses JavaScript BigInt internally, so it converts arbitrarily large integers exactly — you can paste a 200-digit number and every base stays precise, with no rounding or overflow. Q: Which bases can I convert between? A: Any whole-number base from 2 to 36. That covers binary (2), octal (8), decimal (10), duodecimal (12), hexadecimal (16), Base32 and Base36. Digits 0-9 are used first, then letters A-Z represent values 10 through 35. Q: Does it handle the 0x, 0b and 0o prefixes? A: Yes. If you paste a literal like 0xFF into the hex row, 0b1010 into the binary row or 0o17 into the octal row, the matching prefix is stripped automatically so the value parses correctly. Q: Why are letters used in higher bases? A: Once a base goes above 10 it needs symbols for values larger than 9. The standard convention extends the digits with letters: A is 10, B is 11, and so on up to Z which is 35 in base 36. That is why a hex value like FF means 255. Q: Is my data private? A: Completely. Every conversion happens locally in your browser using built-in math — no number you enter is ever sent to a server, and your saved history lives only in your own browser storage. #### Markdown to PDF Converter URL: https://geratools.com/markdown-to-pdf Free Markdown to PDF converter. Paste or write Markdown, see a live preview, then export a clean, typeset PDF with custom page size, margins, fonts and accent colour. 100% client-side — nothing is uploaded. How to use: 1. Paste or write your Markdown: Type into the editor on the left, or paste an existing Markdown document. The preview on the right updates as you type. 2. Set the title and page options: Add a document title and optional author line, then choose A4 or US Letter, margin width, font scale and an accent colour. 3. Export the PDF: Click Export PDF. The styled document downloads instantly with headings, lists, tables, code blocks and page numbers laid out by jsPDF. FAQ: Q: Does this Markdown to PDF converter upload my document? A: No. Both the live preview and the PDF are generated entirely in your browser using JavaScript. Your text never leaves your device, there is no server call, and the tool works offline once the page has loaded — ideal for confidential notes, contracts or drafts. Q: Which Markdown features are supported in the PDF? A: Headings (h1–h6), bold, italic, inline code, links, bulleted and numbered lists (including nested ones), block quotes, fenced code blocks, horizontal rules and GitHub-flavoured tables. The PDF renderer lays each of these out with proper spacing, an accent colour and automatic page breaks. Q: Can I change the page size, margins and fonts? A: Yes. You can switch between A4 and US Letter, drag the margin and font-scale sliders, and pick any accent colour for headings, links, table headers and quote bars. The settings and your text are auto-saved in this browser so they persist between visits. Q: Why does my PDF look slightly different from the preview? A: The on-screen preview uses your browser fonts and full CSS, while the PDF is drawn with jsPDF using the standard Helvetica and Courier fonts that ship inside every PDF. Layout, structure and colours match closely, but exact letter shapes can differ. The PDF is fully selectable, searchable text rather than an image. Q: Does it handle long documents across multiple pages? A: Yes. The exporter measures available vertical space and automatically starts a new page when content would overflow, keeping code blocks, table rows and paragraphs intact. Optional page numbers and a running header with your title appear on every page. Q: Can I convert Markdown to PDF for free without installing anything? A: Completely free and nothing to install. It runs as a web page, so there is no Pandoc, no command line and no sign-up. Open the page, paste your Markdown and download the PDF — on desktop or mobile. #### REM to PX Converter URL: https://geratools.com/rem-to-px-converter Free rem to px converter. Enter any rem value (or a whole list) and your root font size to see the exact pixel equivalent. Includes batch conversion, Tailwind/Material spacing scale preview, and CSS snippet generation. Runs 100% in your browser — nothing uploaded. How to use: 1. Enter a rem value: Type the size in rem you want to convert — for example 1.5. 2. Set the root font size: Enter your root font-size in pixels. The browser default is 16. Use 10 if your stylesheet sets html to 62.5%. 3. Read the pixel result: The equivalent px value and formula appear instantly below the inputs. 4. Switch to Batch for multiple values: Click the Batch tab and paste a space- or comma-separated list of rem values to convert them all at once. 5. Use Scale Preview for design tokens: Click Scale Preview to see the full Tailwind spacing scale, Material 4dp grid, or Tailwind typography scale resolved to px at your chosen root size. FAQ: Q: How do I convert rem to px? A: Multiply the rem value by the root font-size in pixels. With the default 16px root: 1.5rem × 16 = 24px. The formula is simply px = rem × root-font-size. Q: What is the default root font size in browsers? A: All major browsers default the root (html) font-size to 16px, meaning 1rem = 16px unless your stylesheet overrides it. The most common override is html { font-size: 62.5%; } which makes 1rem = 10px. Q: What is the 62.5% rem trick? A: Setting html { font-size: 62.5%; } maps 1rem to 10px (because 62.5% of 16 = 10). This makes rem values read like px divided by 10 — 1.6rem = 16px, 2.4rem = 24px. Set the root font size to 10 in this converter to match that setup. Q: What is the difference between rem and em? A: rem (root em) is always relative to the html element font-size, so it is consistent everywhere on the page. em is relative to the current element font-size, which compounds when elements nest — a 1.2em inside another 1.2em element equals 1.44× the root size. rem avoids that compounding and is generally easier to reason about. Q: Why should I use rem instead of px for font sizes? A: Using rem for typography respects the user browser font-size preference. When someone increases their default text size in browser settings, rem-based layouts scale with it, making the page more accessible. Fixed px values ignore that preference and can make text unreadably small for users who rely on larger defaults. Q: How does this converter handle the Tailwind spacing scale? A: The Scale Preview tab lists every Tailwind spacing token (0 through 96) with its rem value and the resolved px value at your chosen root size. At 16px root, space-4 (1rem) = 16px; at 10px root it = 10px. You can also copy the whole scale as CSS custom properties. ### Network & DevOps #### Common nginx Location Block Patterns URL: https://geratools.com/common-nginx-location-patterns Reference for nginx location block modifiers — exact (=), preferential prefix (^~), case-sensitive (~) and case-insensitive (~*) regex, and plain prefix — with the exact matching priority order nginx applies. How to use: 1. Enter a request path: Type the URI you want to test, such as /images/logo.png or /api/v1/users. 2. Pick your location blocks: Toggle the example location blocks on, or rely on the built-in set, to see which ones could match the path. 3. Read the winning block: The tool applies nginx's real priority rules — exact, then preferential prefix, then regex, then longest prefix — and highlights the block nginx would actually use. FAQ: Q: What is nginx's location matching priority order? A: First an exact (=) match wins immediately. Otherwise nginx finds the longest matching plain prefix; if that prefix used ^~ it is selected and regexes are skipped. Otherwise regex locations (~ and ~*) are tried in file order and the first match wins. If no regex matches, the longest plain prefix found earlier is used. Q: What does the ^~ modifier do? A: ^~ marks a prefix location as preferential. If it is the longest matching prefix, nginx selects it and does not evaluate any regular-expression locations at all. It is the standard way to serve a directory like /static/ without regex blocks intercepting the request. Q: Are regex locations tried in priority order or file order? A: File order. Among regular-expression locations (~ for case-sensitive, ~* for case-insensitive), nginx tries them top to bottom in the configuration and uses the first one that matches. Length does not matter for regexes, so ordering in the file is significant. Q: How does the longest-prefix rule work? A: For plain prefix locations nginx remembers the longest one whose prefix matches the start of the URI. So with /docs/ and /docs/api/ both matching /docs/api/page, the longer /docs/api/ wins. This is independent of where the blocks appear in the file. Q: Does a trailing slash in a location matter? A: Yes for prefix matching length. location /images and location /images/ are different prefixes; /imagesfoo matches the former but not the latter. Choose the trailing slash deliberately when you want to scope a match to a directory rather than a name prefix. #### DNS Zone File Parser URL: https://geratools.com/dns-record-parser Free BIND zone file parser. Tokenizes RFC 1035 master-file syntax (SOA, NS, MX, A, AAAA, CNAME, TXT) into a structured table with owner-name inheritance and TTL normalization. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your zone file: Drop a BIND master file (or an export from your DNS provider) into the text area. The bundled sample shows the expected format. 2. Read the parsed table: Each resource record is split into owner name, TTL, class, type, and RDATA, with relative names resolved against $ORIGIN. 3. Check TTLs and errors: TTL suffixes like 1h30m are normalized to seconds, and any line with an unknown type or missing RDATA is flagged. FAQ: Q: What zone file syntax does this support? A: It follows the RFC 1035 master file format used by BIND. It handles $ORIGIN and $TTL directives, owner-name inheritance, the @ origin shorthand, semicolon comments, and multi-line records wrapped in parentheses such as SOA. Q: How are relative names resolved? A: A name without a trailing dot is treated as relative and the current $ORIGIN is appended. A name ending in a dot is fully qualified and left unchanged. The @ symbol expands to the current origin. Q: How does TTL inheritance work? A: If a record omits its TTL, the value from the most recent $TTL directive is used. The tool also converts TTL suffixes (s, m, h, d, w) into seconds so 1h30m becomes 5400. Q: Why is a record flagged as an error? A: A record is flagged when its type is not a recognised DNS record type, or when a record that requires RDATA has none. Misplaced tokens usually mean a missing owner name or a stray comment character. Q: Is my zone file uploaded anywhere? A: No. Parsing happens entirely in your browser using JavaScript. The zone file never leaves your device, which makes it safe for internal or sensitive DNS exports. #### DNS Response Codes (RCODE) URL: https://geratools.com/dns-response-codes Reference for DNS RCODE values 0–23 including standard codes like NXDOMAIN and SERVFAIL plus extended EDNS and TSIG errors, each with its RFC and a plain-English diagnostic explanation. Bundled offline. How to use: 1. Search by code or name: Type a number like 3, a mnemonic like NXDOMAIN, or a keyword such as servfail or refused. 2. Read the meaning: Each result shows the mnemonic, full name, originating RFC and what the code means when you see it. 3. Diagnose the resolver: Use the explanation to tell apart a missing name (NXDOMAIN), a broken server (SERVFAIL) and a policy block (REFUSED). FAQ: Q: What does SERVFAIL (RCODE 2) actually mean? A: SERVFAIL means the name server could not process the query because of an internal problem. Common causes are an unreachable upstream, a misconfigured zone, or a DNSSEC validation failure on the resolver. Q: How is NXDOMAIN different from a NoError empty answer? A: NXDOMAIN (RCODE 3) asserts the queried name does not exist at all. A NoError response with zero answer records means the name exists but has no record of the requested type — for example an A query against a name that only has MX records. Q: Why are RCODEs above 15 called extended? A: The DNS header field for RCODE is only 4 bits, so it can hold 0–15. Codes 16 and up are carried in the EDNS0 OPT record or in TSIG/TKEY data, which is why they only appear when those extensions are in use. Q: What causes a BADTIME (RCODE 18) error? A: BADTIME is a TSIG failure meaning the request timestamp fell outside the allowed fudge window. It almost always indicates clock skew between the client and the server, so syncing both to NTP usually fixes it. Q: Is REFUSED a failure of my query or the server's policy? A: REFUSED (RCODE 5) is a policy decision: the server understood the query but declined to answer. Typical reasons are recursion being disabled for your IP or a zone transfer being denied to an unauthorised client. #### IPv4/IPv6 CIDR Range Calculator URL: https://geratools.com/ipv4-ipv6-cidr-calculator Compute the full details of any IPv4 or IPv6 CIDR block in your browser: network address, broadcast address, subnet mask, first and last usable host, wildcard mask and total host count. Built for firewall and network security engineers. How to use: 1. Enter a CIDR block: Type an IPv4 or IPv6 address with a prefix length, for example 192.168.1.0/24 or 2001:db8::/48. 2. Read the computed range: The tool derives the network address, mask, host range and total address count from the prefix. 3. Use the values in your rules: Copy the network and broadcast addresses into firewall allow/block lists or routing tables. FAQ: Q: What does the prefix length mean? A: The prefix length (the number after the slash) is how many leading bits of the address identify the network. A /24 fixes the first 24 bits, leaving 8 bits — 256 addresses — for hosts. Q: Why are usable hosts two fewer than the total for IPv4? A: In a normal IPv4 subnet the first address is the network identifier and the last is the broadcast address, so neither is assignable to a host. A /24 has 256 total but 254 usable addresses. Q: Does IPv6 have a broadcast address? A: No. IPv6 has no broadcast address; it uses multicast instead. This tool therefore shows the first and last address of an IPv6 range without reserving a broadcast, and does not subtract usable hosts. Q: How are /31 and /32 handled? A: A /32 is a single host with no broadcast. A /31 is a two-address point-to-point link (RFC 3021) where both addresses are usable. The tool reports these special cases instead of subtracting two. Q: Is my input sent to a server? A: No. All bit arithmetic is performed locally in JavaScript using BigInt, so the addresses you enter never leave your browser. #### Kubernetes Status Conditions URL: https://geratools.com/kubernetes-status-conditions Reference for common Kubernetes resource status conditions — PodScheduled, Ready, Available, Progressing, MemoryPressure, Bound and more — explaining the True/False/Unknown semantics and how to fix each. How to use: 1. Pick a resource: Filter to Pod, Node, Deployment, PVC or Job to see only that resource's conditions. 2. Search a condition: Type a condition type such as "Progressing" or a symptom keyword to find it. 3. Apply the fix: Read the meaning, the True versus False semantics and the suggested remediation. FAQ: Q: What does a False Ready condition on a pod mean? A: Ready=False means the pod is not serving traffic and is excluded from its Service endpoints. It usually follows ContainersReady=False, so check the container's readiness probe and logs. The pod may still be starting or crash-looping. Q: Why is my deployment showing ProgressDeadlineExceeded? A: The Progressing condition turns False with reason ProgressDeadlineExceeded when the new pods cannot become ready within progressDeadlineSeconds. Inspect the new ReplicaSet's pods and events for image pull errors, failing probes or resource limits. Q: What causes a node MemoryPressure or DiskPressure condition? A: MemoryPressure=True means available node memory dropped below the kubelet eviction threshold; DiskPressure=True means disk did. Both trigger pod eviction and image garbage collection. Free resources, set pod limits, or add capacity to clear them. Q: My PVC is stuck — what does Bound versus Pending mean? A: A PersistentVolumeClaim with no Bound condition stays Pending when no PersistentVolume matches its size and access modes, or when no dynamic provisioner is available. Check the StorageClass and that the requested capacity and accessModes are satisfiable. Q: What does an Unknown condition status indicate? A: Unknown means the controller cannot determine the condition, most often because the reporting component stopped responding. A Node Ready=Unknown typically means the kubelet stopped sending heartbeats — investigate node networking and kubelet health. #### MAC Address Lookup URL: https://geratools.com/mac-address-lookup Free MAC address lookup that decodes the OUI vendor prefix and the IEEE control bits of any EUI-48 MAC address, showing unicast vs multicast and universally vs locally administered. Analysed entirely in your browser with no lookup request — nothing is sent anywhere. How to use: 1. Enter a MAC address: Type or paste a MAC address in any common format — colon, dash, dot or plain 12 hex digits. 2. Read the analysis: The tool normalises the address, extracts the 3-octet OUI, and reports the vendor (when known), the cast type and the administration type. 3. Check the control bits: See whether the address is unicast or multicast and whether it is universally administered (a real vendor OUI) or locally administered (often a randomised, privacy MAC). FAQ: Q: Is the MAC address sent anywhere for the lookup? A: No. The address is analysed entirely in your browser and no network request is made, so the MAC is never transmitted. Vendor names come from a small built-in list, not a live query. Q: How are unicast, multicast, universal and local decided? A: They come directly from the first octet's two lowest bits, as defined by IEEE 802. Bit 0 is the I/G bit (0 = unicast, 1 = multicast) and bit 1 is the U/L bit (0 = universally administered, 1 = locally administered). This is fully deterministic. Q: Why does my phone's Wi-Fi MAC show an unknown vendor? A: Modern phones use randomised, locally-administered MAC addresses for Wi-Fi privacy. These have the U/L bit set and intentionally do not map to a real manufacturer, so the vendor will show as not in the local list. Q: What is an OUI? A: An OUI (Organisationally Unique Identifier) is the first 3 octets (24 bits) of a MAC address. The IEEE assigns each OUI block to a manufacturer, so it identifies who made the network chip. The remaining 3 octets are the device-specific serial assigned by that manufacturer. Q: What MAC address formats are accepted? A: Any common format works — colon-separated (3C:5A:B4:00:11:22), dash-separated, Cisco dotted (3c5a.b400.1122) or plain 12 hex digits. The tool strips all separators and reads the 12 hex characters, so spacing and case do not matter. Q: Does this tool find the vendor for every MAC address? A: No. It uses a small curated list of common OUIs rather than the full IEEE registry, because a complete lookup would require a network request and this tool is deliberately offline. Common vendors like Apple, Google, Cisco, VMware and Raspberry Pi are covered; anything else is reported as not in the local list. Q: Can I tell a real device from a randomised address? A: Yes — check the U/L (universal/local) bit. A universally administered address is a genuine factory OUI tied to a manufacturer. A locally administered address has the U/L bit set and is typically a randomised privacy MAC or a virtual NIC, with no real vendor. ### More Developer Tools #### Merge PDF URL: https://geratools.com/merge-pdf Free in-browser PDF merger. Combine multiple PDF files into a single document, drag pages to reorder, and download instantly. 100% client-side — your files never leave your device. How to use: 1. Add your PDF files: Drop your PDF files onto the box or click to choose them. Add as many as you like — each file shows its page count and size. 2. Put them in the right order: Drag any file up or down in the list to reorder it, or use the up and down arrows. The final document follows this exact order. 3. Merge and download: Name your output file, click Merge, and download the single combined PDF. Everything runs in your browser — nothing is uploaded. FAQ: Q: Are my PDF files uploaded to a server? A: No. This tool merges your PDFs entirely inside your browser using the pdf-lib library. The files are read from your device, combined in memory, and the result is generated locally — nothing is ever sent over the network. That makes it safe for contracts, payslips, medical records and other private documents. Q: How many PDFs can I merge at once? A: There is no fixed limit — you can add dozens of files. The practical ceiling is your device's memory, because the entire merge happens locally. Merging a handful of normal documents (a few hundred pages total) is instant; very large scanned PDFs use more RAM, so combine those in smaller batches if your browser slows down. Q: Can I change the order of the pages? A: Yes. Each file appears as a row you can drag up or down to reorder, and there are arrow buttons for precise moves. The merged PDF keeps the files in exactly the order shown in the list, so you control which document comes first, second, and so on. Q: Will merging reduce the quality of my PDFs? A: No. Pages are copied losslessly from each source file into the new document, so text stays selectable, images keep their original resolution, and vector graphics remain sharp. Merging only joins the pages together — it does not re-compress or downscale anything. Q: Can it merge password-protected PDFs? A: It can read and merge PDFs that only have permission restrictions (such as no-print flags), but it cannot open files locked with an open password. If a file is password-protected to open, remove the password in your PDF reader first, then merge the unlocked copy here. Q: Does it work offline and on mobile? A: Yes. Because all the work is done in your browser, the merger keeps working even with no internet connection once the page has loaded, and it runs on phones and tablets as well as desktops. The drag-to-reorder list and arrow buttons both work with touch. #### Accent Fold (Search Normaliser) URL: https://geratools.com/accent-fold Fold accented and diacritical characters to their plain ASCII bases so search queries match regardless of accents. Combines NFD stripping with ligature expansion. Runs entirely in your browser. How to use: 1. Paste text to fold: Enter the word, name, or query you want to normalise for search matching. 2. Choose case folding: Optionally lowercase the result so matching ignores both case and accents. 3. Use the folded output: Copy the ASCII-folded text to use as a search key or to compare against an index built the same way. FAQ: Q: What is accent folding? A: Accent folding maps accented characters to their unaccented ASCII equivalents so that café and cafe are treated as the same term. Search engines apply it on both the index and the query so users find results regardless of how they type accents. Q: How is it different from just stripping diacritics? A: Stripping diacritics removes separable combining marks. Accent folding goes further by also expanding ligatures and special letters that have no combining mark, such as ß to ss, æ to ae, and ø to o, giving fully ASCII output. Q: Why fold the query and the index the same way? A: Matching only works if both sides are normalised identically. If you fold the stored term to cafe but search for café unfolded, the comparison fails. Apply the exact same folding pipeline when building the index and when handling each query. Q: Should I also lowercase? A: For most case-insensitive search you should fold case as well, so Café, CAFÉ, and cafe all collapse to cafe. The optional lowercase toggle here lets you produce a single canonical key for comparison. #### Android APK Inspector URL: https://geratools.com/android-apk-inspector Inspect an Android APK in your browser: read the package name, version name and code, min and target SDK, and every declared permission. Decodes AndroidManifest.xml from the binary AXML format locally — the APK is never uploaded. How to use: 1. Select an APK: Choose an .apk file. It is read locally in your browser — nothing is uploaded. 2. Let it decode the manifest: The tool unzips the APK, locates AndroidManifest.xml and decodes its binary AXML format. 3. Review the results: See the package name, version, SDK levels and the full list of declared permissions. FAQ: Q: Why does an APK manifest need decoding? A: Inside an APK the AndroidManifest.xml is not plain text. It is compiled into Android's binary XML (AXML) format, which packs tags, attributes and a string pool into a chunk-based binary layout. The tool decodes that format to recover readable values. Q: How does a browser read inside an APK? A: An APK is a ZIP archive. The tool reads the ZIP central directory to find the AndroidManifest.xml entry, then inflates it using the browser's built-in DecompressionStream before decoding the binary XML. Q: Is the APK uploaded? A: No. The file is read with the FileReader API and processed entirely in your browser. This matters because APKs can contain proprietary or unreleased code; nothing is sent to a server. Q: Why might some values show as unknown? A: A few manifests reference attribute values through resource IDs that live in the compiled resources rather than the manifest itself. Those appear as numeric references; the core fields like package, version and permissions decode directly. #### BPM Detector URL: https://geratools.com/audio-bpm-detector Decode an MP3 or WAV with the Web Audio API and estimate its tempo using an energy-onset envelope plus autocorrelation over the 60–200 BPM range, with octave correction. Runs entirely in-browser; the audio file stays local. How to use: 1. Load a track: Choose an MP3, WAV, OGG, or M4A. It is decoded with the Web Audio API entirely in your browser. 2. Let it analyse: The tool builds an onset-strength envelope and autocorrelates it to find the most likely tempo period. 3. Read the BPM: The estimated tempo is shown along with the strongest candidates so you can sanity-check half-time or double-time results. FAQ: Q: How does BPM detection work here? A: The audio is split into short frames; the loudness (RMS energy) of each frame forms an envelope. The positive change in that envelope marks beat onsets, and autocorrelating those onsets reveals the repeating period that corresponds to the tempo. Q: Why does it sometimes show half or double the tempo I expect? A: Autocorrelation strongly responds to the beat period and its multiples, so a 120 BPM track can correlate at 60 or 240 too. The tool applies octave correction to fold the result into a typical musical range, but the raw candidates are listed so you can choose. Q: How accurate is it? A: For steady, percussive music it is usually within a couple of BPM. Tempo varies and rubato passages, sparse percussion, or heavy reverb reduce accuracy, so treat the number as a well-informed estimate. Q: Does the file get uploaded? A: No. Decoding and analysis happen in your browser via AudioContext, so nothing is sent to a server and the tool works offline. Q: What tempo range does it cover? A: It searches lags corresponding to roughly 60–200 BPM, then applies octave correction toward a 70–180 BPM range, which covers the vast majority of popular and dance music. #### Audio Waveform Viewer URL: https://geratools.com/audio-waveform-viewer Decode a WAV, MP3, or OGG with the Web Audio API and render a peak-style Canvas waveform with zoom, peak-level (dBFS) readout, and clipping highlighting. Works offline; your audio file never leaves the browser. How to use: 1. Load an audio file: Pick a WAV, MP3, OGG, or M4A file. It is decoded with the Web Audio API entirely in your browser. 2. Inspect the waveform: The Canvas draws a peak waveform; clipped samples are shown in red so you can spot distortion at a glance. 3. Zoom in: Increase the zoom slider to stretch the waveform horizontally and inspect transients, gaps, or fades in detail. FAQ: Q: How is the waveform drawn? A: Each horizontal pixel represents a bucket of samples. The tool finds the minimum and maximum sample in that bucket and draws a vertical line between them — the standard peak-waveform rendering used by audio editors. Q: What does the red colour mean? A: Red marks pixel columns that contain clipped samples — audio that has reached or exceeded full scale (±1.0). Clipping causes audible distortion, so red regions are worth re-checking against your source. Q: What is the peak dBFS value? A: It is the loudest sample in the whole file expressed in decibels relative to full scale, computed as 20·log10(peak). A value near 0 dBFS means the audio is close to clipping; very negative values mean it is quiet. Q: Is my file uploaded? A: No. The file is read into an ArrayBuffer and decoded locally with AudioContext. Nothing is sent to any server, so the viewer works offline and keeps your audio private. Q: Why is the waveform mono even for stereo files? A: For display, the channels are averaged into a single mono waveform so the whole file fits one view. Peak level and clipping statistics still consider every channel separately. #### BiDi / RTL Text Inspector URL: https://geratools.com/bidi-text-inspector Free BiDi text inspector. Scans text or filenames for invisible Unicode bidirectional control characters such as RLO, LRE, LRI and PDF that enable the "Trojan Source" filename and source-code spoofing attacks. Runs entirely in your browser. How to use: 1. Paste the text or filename: Drop in a filename, code snippet, commit message or any string you want to check. 2. Read the report: Every invisible bidirectional control character is listed with its name, code point and position, and shown inline as a labelled marker. 3. Clean it up: Use the "strip controls" output to get a copy of the text with all BiDi control characters removed. FAQ: Q: What are BiDi control characters? A: They are invisible Unicode characters that change how surrounding text is laid out — left-to-right or right-to-left. Examples include RLO (U+202E), LRE (U+202A), LRI (U+2066) and PDF (U+202C). They are legitimate for mixing Arabic or Hebrew with Latin text but can be abused to hide or reorder content. Q: What is the Trojan Source attack? A: Trojan Source (CVE-2021-42574) uses BiDi overrides to make source code or a filename render in a different order than it is stored, so a reviewer sees safe-looking code while the compiler runs something else. This tool surfaces those hidden characters. Q: How does a filename spoof work? A: An RLO character before, say, gpj.exe makes it display as exe.jpg, so a victim thinks they are opening an image when it is really an executable. The inspector reveals the override so the real extension is visible. Q: Is anything uploaded? A: No. The scan runs in JavaScript in your browser against a fixed list of bidirectional control code points. Your text never leaves the page. Q: Will normal text ever be flagged? A: Only if it genuinely contains bidirectional control characters. Plain Latin text, and even ordinary Arabic or Hebrew without explicit overrides, produces no flags. #### Blender Keyboard Shortcuts URL: https://geratools.com/blender-shortcuts Searchable Blender shortcut reference for the 3D Viewport, UV, Node and Graph editors across Object, Edit, Sculpt and Pose modes, using Blender's default keymap. How to use: 1. Search for a tool: Type an action such as extrude, bevel, or unwrap. The table filters across the action, editor and keys instantly. 2. Pick an editor: Filter by 3D Viewport, UV Editor, Node Editor, Graph Editor or Global to see shortcuts for the area you are working in. 3. Narrow by mode: For the 3D Viewport, choose Object, Edit, Sculpt or Pose to show only shortcuts that apply in that mode plus universal ones. FAQ: Q: How do I move, rotate and scale in Blender? A: Press G to grab (move), R to rotate, and S to scale the selection. After pressing one, type X, Y, or Z to lock the operation to that axis, then move the mouse or type a number, and click or press Enter to confirm. Q: What is the shortcut for extrude and loop cut? A: In Edit mode, E extrudes the selected region, Ctrl R adds a loop cut (scroll to add more cuts, then click to slide), and Ctrl B bevels the selected edges. I insets faces and K starts the knife tool. Q: How do I switch between Object and Edit mode? A: Press Tab to toggle between Object and Edit mode on the active object. Ctrl Tab opens a pie menu to jump to any mode such as Sculpt, Weight Paint, or Pose, depending on the object type. Q: Do these match the Industry Compatible keymap? A: No. This reference uses Blender's default keymap. The Industry Compatible keymap remaps many actions to match other 3D software, for example select with left click and different transform keys, so a few entries will differ if you switch keymaps in Preferences. Q: My Numpad shortcuts do not work, what should I do? A: Several view shortcuts use the numeric keypad. On a keyboard without one, enable Emulate Numpad in Preferences under Input, which maps the top number-row keys to the Numpad functions. #### BMP / ICO File Inspector URL: https://geratools.com/bmp-ico-inspector Free BMP and ICO inspector that decodes the BITMAPFILEHEADER and BITMAPINFOHEADER of a .bmp, or the icon directory of a multi-resolution .ico, showing width, height, bit depth, compression and per-image entries. Runs locally with DataView, no upload. How to use: 1. Load a BMP or ICO file: Drop a .bmp or .ico file onto the box or click to browse. The header bytes are decoded with DataView and the file never leaves your device. 2. Read the header fields: For a BMP the inspector shows file size, pixel-data offset, width, height, bit depth, compression and color count. For an ICO it lists every image in the directory. 3. Compare ICO resolutions: A multi-resolution .ico contains several images; the table shows each one's width, height, bit depth and byte size so you can verify a favicon includes 16, 32 and 48 pixel variants. FAQ: Q: What is the difference between BITMAPFILEHEADER and BITMAPINFOHEADER? A: BITMAPFILEHEADER is the first 14 bytes of a BMP — the BM signature, total file size and the offset where pixel data begins. BITMAPINFOHEADER (usually the next 40 bytes) describes the image itself: width, height, color planes, bit depth, compression and resolution. Q: Why is the BMP height sometimes negative? A: A positive height means the rows are stored bottom-up (the standard for BMP). A negative height means top-down row order. The inspector reports the sign and shows the absolute pixel height. Q: How does an ICO store multiple sizes? A: An .ico begins with a 6-byte header (reserved, type=1, image count) followed by one 16-byte directory entry per image. Each entry gives the width, height, color count, bit depth and the byte offset and size of that image, so a single file holds many resolutions. Q: What do the BMP compression codes mean? A: 0 is BI_RGB (uncompressed), 1 is BI_RLE8, 2 is BI_RLE4, 3 is BI_BITFIELDS (custom channel masks, common for 16 and 32-bit), 4 is BI_JPEG and 5 is BI_PNG. The inspector labels the code it reads from the header. Q: Is my image uploaded anywhere? A: No. All parsing happens in your browser with FileReader and DataView. No bytes are transmitted, so the inspector works offline and keeps your files private. #### Browser Fingerprint Preview URL: https://geratools.com/browser-fingerprint-preview Collect the common browser fingerprinting signals your current browser exposes — user-agent, screen and colour depth, timezone, language, a canvas hash, WebGL renderer, hardware concurrency, device memory and more — using only browser APIs. Everything is displayed locally and nothing is transmitted; it is a self-inspection tool for privacy-conscious users. How to use: 1. Open the tool: The preview reads your browser's exposed signals automatically on load. No input is required. 2. Review each signal: Scroll the table of signals — user-agent, screen, timezone, canvas hash, WebGL renderer and more — to see what trackers can read. 3. Compare across browsers: Open the same page in a hardened browser or private window to see how much the signals change and how unique you appear. FAQ: Q: What is browser fingerprinting? A: Fingerprinting combines many small, individually-common browser attributes — fonts, screen size, canvas rendering quirks, timezone — into a signature that is often unique enough to track a device across sites without cookies. The more distinctive your combination, the easier you are to follow. Q: Is any of this data sent to a server? A: No. Every signal is read with browser APIs and rendered locally on this page. Nothing is uploaded, logged, or stored, so you can inspect your own fingerprint safely. Q: What is a canvas hash? A: The tool draws text and shapes to an off-screen canvas and hashes the resulting pixels. Tiny differences in GPU, drivers, anti-aliasing, and font rendering make this hash vary between devices, which is why it is a strong fingerprinting signal. Q: Why does my WebGL renderer reveal my GPU? A: The WebGL debug info extension exposes the unmasked GPU vendor and renderer string (for example Apple M2 or NVIDIA GeForce). That string is highly identifying, which is why privacy browsers spoof or block it. Q: How do I reduce my fingerprint? A: Use a browser with anti-fingerprinting protection (Tor Browser, Brave, or Firefox resistFingerprinting), keep it at default window sizes, disable unnecessary extensions, and avoid rare fonts and settings. The goal is to look like the crowd, not to hide everything. #### Adler-32 Checksum Calculator URL: https://geratools.com/checksum-adler32 Free Adler-32 checksum calculator (RFC 1950, used by zlib and PNG) for text or raw hex bytes, showing the combined value plus the A and B sums in hex and decimal. Runs entirely in your browser; nothing is uploaded. How to use: 1. Choose an input mode: Select Text to checksum a UTF-8 string, or Hex bytes to checksum raw byte values like 31 32 33. 2. Enter your data: Type or paste your text or hex bytes. The Adler-32 updates live as you type. 3. Copy the result: The 32-bit checksum appears in hexadecimal and decimal, with the A and B sums shown — click Copy hex to copy it. FAQ: Q: How is Adler-32 calculated? A: Adler-32 keeps two running sums modulo 65521 (the largest prime below 2^16). Sum A starts at 1 and adds each byte; sum B adds the current A after every byte. The checksum is (B << 16) | A, giving a 32-bit value. Q: How can I check the result is correct? A: The standard check string is the ASCII text "123456789", which produces 0x091E01DE. A single empty input produces 0x00000001, since A starts at 1 and B stays 0. Matching values confirm the implementation. Q: Is Adler-32 better than CRC-32? A: Adler-32 is faster to compute than CRC-32 because it only does additions, but it is weaker for very short messages and detects fewer error patterns. It is used in zlib and PNG where speed matters and data is rarely tiny. Q: Is Adler-32 a cryptographic checksum? A: No. Adler-32 detects accidental corruption only and is trivial to forge. Never use it for security, passwords, or integrity against deliberate tampering — use SHA-256 or BLAKE3 instead. Q: Why does Adler-32 use modulo 65521? A: 65521 is the largest prime below 2^16, so each sum still fits in 16 bits while the prime modulus distributes values more uniformly than a power-of-two would. The two 16-bit sums then pack into one 32-bit checksum. Q: What makes Adler-32 a rolling checksum? A: Both sums are simple additions, so the checksum of a sliding window can be updated in constant time by subtracting the outgoing byte and adding the incoming one. rsync exploits this Adler-style rolling property to test block matches at every byte offset cheaply. #### DOCX Metadata Viewer URL: https://geratools.com/docx-metadata-viewer Free DOCX metadata viewer. Unzips a .docx in your browser and reads docProps/core.xml for creator, last modified by, created and modified dates, revision count, title and word stats. Useful for document forensics — nothing is uploaded. How to use: 1. Select a .docx file: Choose a Word .docx document. It is unzipped and read locally — the file never leaves your browser. 2. Let it read the core properties: The tool extracts docProps/core.xml and docProps/app.xml from the ZIP package and parses the standard metadata fields. 3. Review the metadata: See the creator, last editor, creation and modification timestamps, revision number and word counts in a clean table. FAQ: Q: How can a browser read DOCX metadata without Word? A: A .docx file is really a ZIP archive of XML parts. The tool reads the ZIP's central directory, inflates the docProps/core.xml and docProps/app.xml entries with the browser's built-in decompression, and parses the standard Dublin Core and Office metadata fields. No server is involved. Q: What is the revision count? A: The revision number is incremented by Word each time the document is saved. A high revision count suggests heavy editing; a count of 1 means the file was saved only once since creation, which can be a useful forensic signal. Q: Why are some fields blank? A: Word only writes a property if it was set. Anonymous templates, files cleaned of metadata, or documents created by other tools may leave creator, company or title empty. Blank simply means the field was not stored. Q: Can this detect who really wrote a document? A: It shows the creator and last-modified-by names recorded in the file, which come from the Word account or login of the author. These can be edited or spoofed, so treat them as evidence, not proof of authorship. Q: Does it work on old .doc files? A: No. The classic binary .doc format is not a ZIP and uses a completely different OLE structure. This tool only reads the modern Office Open XML .docx format. Convert .doc to .docx first. #### Drill & Tap Size Chart URL: https://geratools.com/drill-tap-size-chart Look up the recommended tap-drill bit size for metric and imperial threaded holes. Covers M-series and UNC/UNF taps with the 75% thread engagement formula shown alongside each standard drill. How to use: 1. Select the thread system: Choose metric for M-series taps or Unified for imperial UNC and UNF taps. 2. Filter to your tap: Type the tap designation such as M6 or 1/4-20 to find the matching row. 3. Drill then tap: Drill the hole with the recommended bit, then run the matching tap to cut the threads. FAQ: Q: How is tap drill size calculated? A: For metric threads the tap drill diameter equals the major diameter minus the pitch, which gives roughly 75 percent thread engagement. For Unified inch threads it equals the major diameter minus one divided by the threads per inch. The tool shows both the standard recommended bit and this calculated value. Q: Why 75 percent thread engagement and not 100 percent? A: A full 100 percent thread adds only about 5 percent more strength but dramatically increases tapping torque and tap breakage risk. The 75 percent target gives nearly all the holding strength while letting the tap cut cleanly, so it is the standard industry recommendation. Q: What is the drill size for an M6 tap? A: A standard M6 by 1.0 mm coarse tap uses a 5.0 mm drill. That follows the rule of major diameter minus pitch, which is 6 minus 1, equalling 5 mm. Fine-pitch M6 threads would need a slightly larger drill. Q: What happens if the drill is too small or too large? A: Too small a hole leaves too much material, raising tapping torque and often snapping the tap inside the hole. Too large a hole produces shallow, weak threads that strip under load. Use the recommended size for reliable, strong threads. Q: Do these sizes work for blind and through holes? A: The drill diameters are the same for both. For blind holes drill deeper than the thread depth to leave room for chips and the tap point, and prefer a bottoming tap to thread close to the bottom of the hole. #### Driving Side by Country URL: https://geratools.com/driving-side-by-country Reference table showing whether each country drives on the left-hand or right-hand side of the road, with the steering-wheel side and notes on notable exceptions. Essential for travelers renting cars abroad. How to use: 1. Search a country: Type a country name to see which side of the road it drives on. 2. Filter by side: Use the selector to list only left-hand-traffic or right-hand-traffic countries. 3. Read the details: Each entry shows the driving side and the corresponding steering-wheel position, plus notes on exceptions. FAQ: Q: Which countries drive on the left? A: About 75 countries and territories use left-hand traffic, covering roughly a third of the world's population. They include the United Kingdom, Ireland, Japan, Australia, New Zealand, India, South Africa, and most of the former British Empire, plus a few others like Indonesia and Thailand. Q: What is the relationship between driving side and steering wheel? A: They are opposite. Countries that drive on the left use right-hand-drive (RHD) cars, with the steering wheel on the right so the driver sits nearer the road centre. Countries that drive on the right use left-hand-drive (LHD) cars. This keeps the driver positioned to see oncoming traffic. Q: Why do some countries drive on the left? A: Left-hand traffic largely traces to historical conventions — mounted travelers kept left to keep their sword arm toward oncoming strangers — preserved through British colonial influence. Most of the world standardized on the right, partly through French and later American influence on road and vehicle design. Q: Are there countries that switched sides? A: Yes. Sweden famously switched from left to right in 1967 (Dagen H), and Samoa switched from right to left in 2009 to align with nearby Australia and New Zealand for cheaper used-car imports. Such changes are rare and carefully planned. Q: Does this affect renting a car abroad? A: Significantly. If you usually drive on the right and rent in a left-hand-traffic country, you will sit on the opposite side, shift with the other hand, and must retrain at junctions and roundabouts. Always check the driving side before booking and allow extra caution. #### EBML / Matroska Inspector URL: https://geratools.com/ebml-inspector Free EBML inspector that parses the Matroska or WebM container of an MKV or WebM file in your browser — decoding the EBML header, Segment, Info and Tracks elements to show codec IDs, track types, duration and language. Runs locally with DataView, no upload. How to use: 1. Load an MKV or WebM file: Drop an .mkv or .webm file onto the box or click to browse. Only the opening container bytes are read with DataView; the file stays on your device. 2. Read the container summary: The inspector decodes the EBML header (doc type and version) plus the Segment Info element, showing the muxing application, title, duration and timestamp scale. 3. Inspect each track: The Tracks element is walked to list every audio, video and subtitle track with its codec ID, track type and language tag. FAQ: Q: What is EBML? A: EBML (Extensible Binary Meta Language) is a binary, tree-structured format — like a binary XML. Matroska (MKV) and WebM are both EBML documents. Every element has a variable-length ID, a variable-length size, and either child elements or a typed value. Q: How are MKV and WebM related? A: WebM is a restricted subset of Matroska. Both use the same EBML container; WebM limits codecs to VP8/VP9/AV1 video and Vorbis/Opus audio and sets the EBML DocType to webm instead of matroska. The inspector reports the DocType so you can tell them apart. Q: How is duration stored? A: Duration lives in the Segment Info element as a floating-point value measured in TimestampScale units (default 1,000,000 nanoseconds = 1 ms). The inspector multiplies duration by the scale and converts to seconds for you. Q: What are the common codec IDs? A: Video codecs appear as strings like V_VP9, V_VP8, V_AV1 or V_MPEG4/ISO/AVC (H.264). Audio codecs appear as A_OPUS, A_VORBIS or A_AAC. Subtitle tracks use S_TEXT/UTF8 or S_TEXT/ASS. The inspector shows the raw CodecID for each track. Q: Is the video uploaded anywhere? A: No. Parsing runs entirely in your browser with FileReader and DataView, reading only the header region of the file. Nothing is transmitted, so the tool works offline and your media stays private. #### Email Header Analyzer URL: https://geratools.com/email-header-analyzer Paste raw email headers and instantly see SPF, DKIM, and DMARC verdicts, the From/Return-Path/Message-ID identity fields, and the full chain of Received server hops with per-hop delays. Runs entirely in your browser — no header content is uploaded. How to use: 1. Get the raw headers: In Gmail open the message, click the three-dot menu and choose 'Show original'. In Outlook use 'View' then 'View message source'. Copy the full header block. 2. Paste them in: Paste everything from the top of the message down to the first blank line. The analyzer unfolds multi-line headers automatically. 3. Read the verdicts and hops: Check the SPF/DKIM/DMARC panel for pass or fail, then scan the delivery hops to see every server the message passed through and how long each leg took. FAQ: Q: Where does the SPF/DKIM/DMARC result come from? A: From the Authentication-Results header (and Received-SPF) that the receiving mail server adds. This tool reads the verdict the server already recorded — it does not re-run DNS lookups or re-verify the DKIM cryptographic signature itself. Q: Is my email content sent anywhere? A: No. Parsing happens entirely in your browser with JavaScript. Nothing you paste — headers or otherwise — is transmitted to any server. Q: Why are the Received hops shown oldest first? A: Mail servers prepend each Received header, so the raw list runs newest-to-oldest. The analyzer reverses them so you read the journey in the order it actually happened, from the sender's first server to your inbox. Q: What does a DMARC 'pass' actually require? A: DMARC passes when the message has an aligned, passing SPF or DKIM result — meaning the authenticated domain matches the visible From domain. A DMARC fail with SPF/DKIM passing usually signals an alignment problem, often from a mailing list or forwarder. Q: What do large gaps between hops mean? A: A long delay between two Received timestamps means the message sat in a queue at that server, commonly due to greylisting, rate limiting, or a backlog. Occasional gaps are normal; a consistently slow hop is worth investigating. #### Emoji Search URL: https://geratools.com/emoji-search Filterable emoji reference with Unicode code point, :shortcode: and one-click copy. Search by name, keyword or category to find the right emoji for Slack, GitHub, Discord or plain text. How to use: 1. Type a search term: Enter a name, keyword or shortcode such as fire, happy or :heart: to filter the list. 2. Narrow by category: Use the category dropdown to limit results to Smileys, Symbols, Food and so on. 3. Copy the emoji: Click Copy to put the glyph on your clipboard, or read the shortcode for chat apps. FAQ: Q: What is an emoji shortcode? A: A shortcode is a colon-wrapped text alias such as :fire: or :heart: that chat apps like Slack, Discord and GitHub auto-replace with the matching emoji. It is handy when you cannot type the glyph directly. Q: How do I find an emoji's Unicode code point? A: Each result shows its primary code point in U+ notation, for example the fire emoji is U+1F525. Code points uniquely identify the character across all platforms even if the picture differs. Q: Why do emojis look different on different devices? A: Unicode defines the meaning and code point of an emoji, but each vendor (Apple, Google, Microsoft, Twitter) draws its own artwork. The same code point can therefore look quite different across phones and apps. Q: Can I search by feeling instead of exact name? A: Yes. Every emoji is tagged with keywords, so searching happy, love or done returns the relevant faces and symbols even when those words are not in the official name. Q: Does copying an emoji send data anywhere? A: No. The emoji set is bundled with the page and filtered locally. Copy uses your browser's clipboard API and never contacts a server. #### Endianness Swapper URL: https://geratools.com/endianness-swapper Free endianness swapper. Paste a hex value and reverse its byte order to convert between big-endian and little-endian, choosing 16, 32 or 64-bit width, with the unsigned integer value of each form. Runs in your browser. How to use: 1. Paste a hex value: Enter the hex bytes, with or without a 0x prefix; spaces and underscores are ignored. 2. Pick a width: Choose the natural size or fix it at 16, 32 or 64 bits so the value is zero-padded to whole bytes. 3. Read the swapped result: The tool reverses the byte order and shows both forms plus their unsigned integer values, with a copy button. FAQ: Q: What is endianness? A: Endianness is the order in which the bytes of a multi-byte value are stored. Big-endian puts the most significant byte first; little-endian puts the least significant byte first. The bit order inside each byte never changes. Q: Which systems use which endianness? A: Network protocols (TCP/IP) use big-endian, called network byte order. Most desktop CPUs (x86, x86-64) and ARM in its default mode are little-endian. This mismatch is why byte swapping is often needed. Q: Does swapping change the bits within a byte? A: No. Swapping reverses the order of whole bytes only. Each byte's two hex digits stay together; only their position in the sequence is reversed. Q: Why pad to a fixed width? A: A value like 0x1234 is two bytes, but if it lives in a 32-bit field you must include the leading zero bytes before swapping, otherwise the result is wrong. Choosing a width zero-pads correctly first. Q: Is my data sent anywhere? A: No. The byte reversal is computed locally in your browser, so nothing is transmitted and the tool works offline once loaded. #### EPUB Metadata Viewer URL: https://geratools.com/epub-metadata-viewer Free EPUB metadata viewer. Drop an .epub file to read its title, author, publisher, language, ISBN/identifier, and cover image — parsed entirely in your browser from the EPUB's ZIP and OPF package. No file is uploaded. How to use: 1. Drop the EPUB: Drag an .epub file onto the box, or click to choose one from your device. 2. Let it parse the package: The tool unpacks the EPUB's ZIP, finds the OPF package document, and reads its Dublin Core metadata and cover reference. 3. Review the details: Title, author, publisher, language, identifier, and cover image are displayed instantly. FAQ: Q: What metadata does an EPUB contain? A: EPUBs store Dublin Core metadata in their OPF package file — typically title, creator (author), publisher, language, date, and an identifier such as an ISBN or UUID. A cover image is referenced from the manifest. This tool reads all of those. Q: How is an EPUB structured? A: An EPUB is a ZIP archive. META-INF/container.xml points to the OPF package document, which lists the book's metadata, its manifest of files, and the reading order. The tool follows that chain to find what it needs. Q: Is my ebook uploaded anywhere? A: No. The file is read with the browser's File API and unzipped locally using the native decompression API. Nothing is sent to a server, so your book and its DRM-free content stay private. Q: Why might the cover not appear? A: Some EPUBs reference the cover unusually or omit it. The tool checks both the standard cover-image manifest property and the legacy meta cover pointer; if neither resolves to an image in the archive, no cover is shown while the text metadata still appears. Q: Does it work on DRM-protected books? A: It reads the package structure of standard EPUBs. Books wrapped in vendor DRM encrypt their contents, so metadata and cover may be unreadable. The tool is intended for your own DRM-free EPUB files. #### Excel Formula Parser & Explainer URL: https://geratools.com/excel-formula-parser Free Excel formula parser and explainer. Paste any Excel or Google Sheets formula to see a parse tree of every function, operator and reference, plus a plain-English explanation. Ideal for auditing inherited spreadsheets — runs in your browser. How to use: 1. Paste the formula: Copy a formula from a cell, including or excluding the leading equals sign, and paste it into the box. 2. Read the explanation: The tool describes in plain English what the formula computes, naming each function and operator from the outside in. 3. Inspect the parse tree: Expand the parse tree to see how functions, operators and references nest, which makes deeply nested formulas easy to audit. FAQ: Q: What does this tool do? A: It tokenizes and parses an Excel formula into an abstract syntax tree, then renders that tree and a readable explanation. It shows the structure and meaning of a formula but does not evaluate it against real cell values, since it has no workbook. Q: Which operators and precedence does it support? A: It supports the full Excel operator set: ^ for power, * and / for multiply and divide, + and - for add and subtract, & for text concatenation, the comparison operators = <> < <= > >=, unary minus, and the trailing % percent operator, all with Excel's standard precedence and right-associative ^. Q: Can it parse nested functions and ranges? A: Yes. It handles arbitrarily nested function calls like IF(SUM(A1:A10)>100, ...), cell and range references with absolute markers such as $A$1 and A1:B2, sheet-qualified references like Sheet1!A1, and defined names. Q: Does it work with Google Sheets formulas? A: Mostly, yes. Google Sheets shares Excel's formula grammar for functions, operators and references, so common formulas parse identically. A few Google-only functions will parse structurally even though their descriptions are not in the built-in glossary. Q: Is my formula sent anywhere? A: No. The formula is tokenized and parsed entirely in your browser. Nothing is uploaded, so you can safely paste formulas from confidential models. #### File Extension Lookup URL: https://geratools.com/file-extension-lookup Look up any file extension to see its format name, MIME content-type, category, and the applications that typically open it. Search a curated database of common file extensions entirely in your browser. How to use: 1. Type an extension: Enter a file extension like png, docx, or svg — with or without the leading dot. 2. Filter or browse: Optionally narrow by category such as image, document, or archive, or just scroll the matches. 3. Read the details: Each result shows the format name, MIME content-type, category, and apps that commonly open the file. FAQ: Q: Do I need to include the dot? A: No. You can type png or .png — the lookup strips a leading dot automatically. Search is case-insensitive, so PNG and png both work. Q: What is a MIME type? A: A MIME (or media) type is a standardized label like image/png that tells software and servers what kind of data a file holds. Web servers send it in the Content-Type header so browsers know how to handle the response. Q: Why might one extension have several meanings? A: Some extensions are reused by unrelated formats. For example .dat is generic and used by many programs. When that happens the entry notes the most common interpretation and that the format may vary. Q: Can the extension be trusted to identify a file? A: Not always. Extensions are just hints and can be renamed. For certainty, inspect the file's magic-number signature or its actual MIME type rather than relying on the extension alone. Q: Does this run offline? A: Yes. The extension database ships with the page and all searching happens in your browser, so no data is sent anywhere and it works without a connection. #### Fiscal Year by Country URL: https://geratools.com/fiscal-year-by-country Look up the government (state budget) fiscal year start and end dates for countries worldwide. See which nations use a calendar year, an April-to-March year, or a July-to-June budget cycle. How to use: 1. Search a country: Type a country name or month into the search box to filter the table. 2. Read the dates: The start and end columns show the day and month the fiscal year runs. 3. Check the note: The note column flags differences between the government year and the personal tax year. FAQ: Q: What is a fiscal year? A: A fiscal year is the 12-month period a government or company uses for budgeting and accounting. It does not have to match the calendar year; many governments run April to March or July to June. Q: Why does the UK government year differ from the tax year? A: The UK central government financial year runs 1 April to 31 March, but the personal income tax year for individuals runs 6 April to 5 April. This split is a historical artefact of the old Lady Day calendar adjustments. Q: Which countries use the calendar year? A: Most of Europe, China, Russia, Brazil, and much of the Middle East align the fiscal year with the calendar year, 1 January to 31 December. This table flags those rows in the note column. Q: Why do Iran and Nepal have unusual start dates? A: They base the fiscal year on non-Gregorian calendars. Iran starts on 1 Farvardin (around 21 March) in the Solar Hijri calendar, and Nepal runs mid-July to mid-July under the Bikram Sambat calendar. Q: Does the US fiscal year match the tax year? A: No. The US federal government fiscal year runs 1 October to 30 September, while the individual income tax year is the calendar year. FY2026, for example, covers October 2025 through September 2026. #### FLAC Metadata Viewer URL: https://geratools.com/flac-metadata-viewer Parse FLAC audio files in your browser to read STREAMINFO (sample rate, bit depth, channels, duration, MD5) and VORBIS_COMMENT tags like title, artist and album. No upload — the file never leaves your device. How to use: 1. Select a FLAC file: Choose a .flac file from your device. Parsing happens locally in your browser. 2. Read the STREAMINFO: The viewer shows sample rate, bit depth, channels, total samples and the exact duration. 3. Review the tags: All Vorbis comment tags (title, artist, album, etc.) and metadata blocks are listed below. FAQ: Q: What is STREAMINFO in a FLAC file? A: STREAMINFO is the mandatory first metadata block of every FLAC stream. It holds the audio fundamentals: sample rate, bit depth, channel count, total sample count and an MD5 signature of the decoded audio. Q: What are Vorbis comments? A: Vorbis comments are FLAC's tagging system, stored in the VORBIS_COMMENT metadata block. They are simple KEY=VALUE pairs such as ARTIST, TITLE, ALBUM and DATE, plus a vendor string identifying the encoder. Q: Is my audio file uploaded anywhere? A: No. The FLAC file is read and parsed entirely in your browser using the FileReader API. Nothing is sent to a server, so even private recordings stay on your device. Q: Why does the duration not match my player exactly? A: Duration is computed as total samples divided by sample rate, which is the exact figure stored in STREAMINFO. Some players round to whole seconds, so small differences in the fractional part are normal. #### Fletcher-16 Checksum Calculator URL: https://geratools.com/fletcher16-text Calculate the Fletcher-16 modular-sum checksum of any text over its UTF-8 bytes. Returns the 4-digit hex value, decimal form, and the two component sums, all computed locally in your browser using the classic two-sums-mod-255 algorithm. How to use: 1. Enter your text: Type or paste the text to checksum. It is encoded as UTF-8 before the Fletcher-16 is computed. 2. Read the checksum: The 4-digit hex value updates instantly, alongside the decimal form and the two component sums sum1 and sum2. 3. Copy the result: Click copy to put the hex checksum on your clipboard for embedding in a packet or comparing against an expected value. FAQ: Q: What is Fletcher-16 used for? A: Fletcher-16 is a lightweight checksum used in protocols and embedded systems where a full CRC is too costly. It catches most single-bit and burst errors with just two byte-sized running sums, making it cheap on small microcontrollers. Q: How is the checksum formed? A: Two 8-bit sums are kept, both modulo 255. sum1 accumulates each byte; sum2 accumulates sum1 after every byte. The 16-bit checksum is (sum2 shifted left 8) OR sum1, which this tool also shows broken into its parts. Q: Why modulo 255 and not 256? A: Using 255 (not a power of two) means a string of zero bytes still changes the position-dependent sum2, and it avoids the blind spots a mod-256 sum has. The trade-off is that the value 255 and 0 are treated as congruent in the reduction. Q: Is Fletcher-16 secure? A: No. It only detects accidental errors and is easy to forge. For any security or anti-tampering need use a cryptographic hash such as SHA-256 or an HMAC. Q: What is a good test value? A: The classic test input abcde produces the Fletcher-16 0xC8F0. The strings abcdef and abcdefgh give 0x2057 and 0x0627 respectively, useful for verifying an implementation. #### Font Metadata Viewer URL: https://geratools.com/font-metadata-viewer Free font metadata viewer. Drop a TTF, OTF, or WOFF file to read its OpenType name table: family name, subfamily, full name, version string, copyright, manufacturer, designer, and licence URL. Parsed entirely in your browser — no upload. How to use: 1. Select a font file: Choose or drag a .ttf, .otf, or .woff file. The bytes are read locally with FileReader and parsed in your browser. 2. Read the name table: The tool decodes the OpenType name table and lists family, version, copyright, manufacturer, designer, and licence entries. 3. Check the licence: Use the licence-description and licence-URL fields to confirm how a downloaded or purchased font may be used. FAQ: Q: What is the OpenType name table? A: The name table (tag 'name') is a required OpenType table that stores human-readable strings about the font: family and style names, version, copyright, trademark, manufacturer, designer, and licensing information, each tagged by a name ID. Q: Is my font file uploaded anywhere? A: No. The font's binary is read in your browser and the name table is parsed with JavaScript on your device. Nothing is sent to any server. Q: Why are some fields empty? A: Font vendors are not required to fill every name ID. Free and amateur fonts often omit the licence URL, designer, or trademark fields. Empty simply means that record is absent in the file. Q: Which formats can it read? A: TrueType (.ttf) and OpenType (.otf) parse directly. WOFF (.woff) is supported because its header points to the same SFNT tables; WOFF2 uses Brotli-compressed tables that this lightweight parser cannot expand, so convert WOFF2 to TTF first. Q: Does the version string tell me which release I have? A: Usually yes — name ID 5 holds a version string like 'Version 2.001'. Combined with the unique ID (name ID 3) it identifies the exact build, which is useful when matching a font to its source or licence. #### Local Font Previewer URL: https://geratools.com/font-preview Free local font previewer. Drop a TTF, OTF, WOFF, or WOFF2 file and instantly see a pangram, full alphabet, numerals, and your own custom text rendered in that font. Uses the CSS Font Loading API — the file never leaves your browser. How to use: 1. Choose a font file: Click the picker or drag a .ttf, .otf, .woff, or .woff2 file onto the drop zone. Nothing is uploaded — the file is read in your browser. 2. Type your sample text: Enter any words you want to see set in the font, or use the built-in pangram and alphabet samples. 3. Adjust the size: Use the size slider to preview the font at body, heading, and display sizes before you install or buy it. FAQ: Q: Is my font file uploaded to a server? A: No. The font is loaded with the browser's CSS Font Loading API (FontFace) directly from the file you choose. It is registered only in the current page and is never sent anywhere. Q: Which font formats are supported? A: TrueType (.ttf), OpenType (.otf), WOFF (.woff), and WOFF2 (.woff2) all work because the browser's native font engine decodes them. Older formats like .eot or .pfb are not supported. Q: Why can I preview a font I have not installed yet? A: The CSS Font Loading API lets a page register a temporary font face from raw bytes without installing it system-wide. The font is available only to this page and disappears when you close the tab. Q: Can I preview multiple fonts at once? A: This tool previews one font at a time so the sample text is unambiguous. Pick a new file to swap fonts instantly; the previous temporary face is removed automatically. Q: Does the preview match how the font looks when installed? A: Yes for shape and metrics — the same font engine renders both. System-level hinting and OS smoothing can differ slightly, but glyph outlines, kerning, and OpenType features render identically. #### G-Code Arc (I/J/K) Calculator URL: https://geratools.com/g-code-arc-calculator Takes an arc start point, end point, and radius and computes the incremental I and J center offsets needed for G02 and G03 CNC arc moves in the XY plane. Shows both possible arc solutions with sweep angle, marks the shorter one, and outputs a ready-to-paste G-code line. Runs in your browser. How to use: 1. Enter start and end points: Type the X and Y coordinates of the arc start and the arc end in your part's work coordinate system. 2. Enter the arc radius: Add the desired arc radius. It must be at least half the straight distance between the two points. 3. Copy the G-code line: The tool shows both arc solutions with their I and J offsets and direction. Copy the line for the arc you want. FAQ: Q: What are I and J in G-code arcs? A: I and J are the incremental offsets from the arc start point to the arc center along the X and Y axes. Most controllers use incremental I and J by default in the XY plane, so I equals center X minus start X and J equals center Y minus start Y. This tool outputs them in that incremental form. Q: Why are there two possible arcs? A: A start point, end point, and radius do not define a unique arc, because the center can sit on either side of the chord connecting the points. That gives two centers and two arcs, one shorter and one longer. The tool shows both and marks the shorter solution. Q: What is the difference between G02 and G03? A: G02 cuts a clockwise arc and G03 cuts a counter-clockwise arc, both viewed looking down the Z axis in the XY plane. The tool reports the correct direction for the minor arc to each center; to take the major arc the long way around, you reverse the G02 or G03 code. Q: Why does it say my radius is too small? A: An arc must reach both endpoints, so its radius cannot be smaller than half the straight-line distance between them. If you see that warning, increase the radius to at least the half-chord value the tool reports, or move the endpoints closer together. Q: Does this work for the YZ or XZ plane? A: This calculator targets the default XY plane used with G17, which covers the large majority of arc programming. For YZ work with G19 or XZ work with G18 the same geometry applies but the offset letters change to J and K or I and K respectively. #### GCP Region & Zone Codes URL: https://geratools.com/gcp-region-codes Searchable Google Cloud Platform region and zone reference with region code, physical location, continent, zone naming, multi-region membership and carbon-free energy status. How to use: 1. Search for a region: Type a region code, city or multi-region into the search box to filter the table instantly. 2. Filter by continent: Use the continent dropdown to narrow the list to North America, Europe, Asia and other geographies. 3. Read the zone codes: Each region lists its zones as the region code plus a letter suffix, ready to paste into gcloud commands. FAQ: Q: What is the difference between a GCP region and a zone? A: A region is a specific geographic location, such as europe-west1 in Belgium. A zone is an isolated deployment area inside a region, named as the region code plus a letter, like europe-west1-b. Spreading resources across zones protects against single-zone failures. Q: What are GCP multi-regions? A: Multi-regions such as us, eu and asia are large geographic areas that span several regions on the same continent. Storage services like Cloud Storage and BigQuery can use a multi-region to replicate data across regions for higher availability and lower cross-region latency. Q: Why are some regions marked low CO2? A: Google publishes a carbon-free energy percentage for each region. Regions flagged low CO2 here run on a high share of carbon-free energy, which lets you reduce the carbon footprint of your workloads by choosing them. These figures change over time. Q: How do I list available zones with gcloud? A: Run gcloud compute zones list to see every zone your project can use, or gcloud compute regions list for regions. This reference is a quick offline lookup; the live CLI is authoritative for quotas and availability. Q: Does this tool fetch data from Google? A: No. All region data is bundled into the page and searched locally in your browser. Nothing is sent to Google or any server. #### GPX Elevation & Distance Stats URL: https://geratools.com/gpx-elevation-stats Calculate total distance with the Haversine formula plus cumulative elevation gain and loss, min/max altitude, average grade, moving time and pace from GPX track points. Includes an elevation chart. Runs fully in your browser. How to use: 1. Load the GPX: Paste the GPX contents or choose a .gpx file from your device. 2. Compute stats: Click Calculate to get distance, elevation gain and loss, altitude range, grade and pace. 3. Read the chart: Review the elevation profile drawn beneath the numbers to spot the climbs and descents. FAQ: Q: How is total distance calculated? A: Distance is the sum of great-circle (Haversine) distances between each pair of consecutive track points using an Earth radius of 6,371 km, which is accurate over the short hops in a GPS log. Q: How are ascent and descent measured? A: The tool walks the elevation series and adds every positive step to the gain total and every negative step to the loss total. A small smoothing threshold ignores tiny jitters so GPS noise does not inflate the climb. Q: What does average grade mean here? A: Average grade is total elevation gain divided by total horizontal distance, expressed as a percent — a rough measure of how steep the route is overall. Q: How is pace computed? A: If the points carry timestamps, moving time is the elapsed time between the first and last point, and pace is that time divided by distance, shown in minutes per kilometre. Q: Is my GPX uploaded? A: No. Parsing and every calculation run locally in your browser — your GPS track is never sent to a server. #### GPX Activity Heatmap URL: https://geratools.com/gpx-heatmap Render a density heat map from multiple GPX files entirely in your browser. Track points are Web-Mercator projected, binned into a density grid, blurred, and painted as a warm-to-cool heat map showing your most-travelled routes. No tracks are uploaded; your activity data stays private. How to use: 1. Select your GPX files: Choose one or many .gpx files exported from your watch, phone, or activity app. They are read locally and never uploaded. 2. Watch the heatmap render: All track points are projected and combined into a single density map drawn on a canvas in your browser. 3. Read the hotspots: Warmer colours (yellow to red) mark the routes you travel most; cool blues mark routes used once or twice. FAQ: Q: Which GPX elements are read? A: The tool reads latitude/longitude from track points (trkpt), route points (rtept), and waypoints (wpt). Points outside valid latitude/longitude ranges are ignored, and invalid XML is skipped safely. Q: How is the heat map computed? A: Each coordinate is projected with the Web Mercator formula so the map keeps the right shape, then snapped into a pixel grid that counts overlapping points. A Gaussian-style blur spreads the density, and intensity is log-scaled and mapped to a blue-to-red colour ramp. Q: Why Web Mercator instead of plain latitude/longitude? A: Plotting raw latitude and longitude stretches areas away from the equator. Web Mercator linearises latitude the same way web map tiles do, so your tracks keep correct proportions and angles at any location. Q: Do I need an internet connection or Strava account? A: No. There are no map tiles, no API keys, and no account needed. The heat map is drawn purely from your own GPX point density, so it works completely offline. Q: Is my location data uploaded? A: Never. Every file is read with the browser's local FileReader and processed on a canvas in your tab. Your routes and home location stay entirely on your device. Q: Why is one corner of my heatmap far brighter than everywhere else? A: That is almost certainly your home. Because every activity starts and ends there, the start/end point accumulates far more overlap than any route. If you plan to share the image, crop or blur that cluster — it is the same signal that let researchers locate military bases from Strava's aggregate heatmap in 2018. Q: My heatmap shows one dot and lots of empty space — what happened? A: A GPS spike: a single erroneous point in the wrong country or out at sea stretches the projection to include it, shrinking all your real tracks to a dot. Find and remove the bad point in that GPX file, or exclude the file, and the map will re-scale correctly. #### GPX Merger URL: https://geratools.com/gpx-merger Merge tracks and waypoints from several GPX files into a single valid GPX document. Each source file becomes its own track segment so timestamps and ordering are preserved. Everything runs in your browser with no upload. How to use: 1. Add your GPX files: Choose two or more .gpx files from your device, or paste their contents one after another. 2. Merge: Click Merge to concatenate every track and waypoint into a single GPX 1.1 document. 3. Copy the result: Copy the merged GPX and save it as a single .gpx file for your device or app. FAQ: Q: How are the files combined? A: Each source GPX becomes its own track segment inside one merged track, kept in the order you add the files, and all waypoints are copied across. This preserves point order and timestamps. Q: Are timestamps and elevation kept? A: Yes. Each track point is copied with its lat, lon, ele and time exactly as it appears in the source, so elevation and time data survive the merge intact. Q: Is anything uploaded? A: No. Files are read and merged entirely in your browser using the built-in XML parser — your GPS data never leaves your machine. Q: What if a file is not valid GPX? A: The tool reports which input failed to parse and skips it, so one bad file does not block merging the rest. Q: Why keep separate segments instead of one continuous line? A: Keeping each source as its own segment avoids drawing a false straight line between the end of one day and the start of the next, which is what you usually want when stitching multi-day logs. #### GPX Route Reverser URL: https://geratools.com/gpx-route-reverser Flip the order of every track point and waypoint in a GPX file so you can navigate a route backwards. Optionally re-spaces timestamps so the reversed track has increasing times. Pure browser JavaScript, no upload. How to use: 1. Load the GPX: Paste the GPX contents or choose a .gpx file from your device. 2. Reverse: Click Reverse to flip the order of all track points so the end becomes the new start. 3. Copy the result: Copy the reversed GPX and load it into your device to navigate the route in the opposite direction. FAQ: Q: What exactly gets reversed? A: The order of every track point across all segments is flipped, and waypoints are reversed too, so the final point of the original route becomes the first point of the reversed one. Q: What happens to timestamps? A: By default the original times are kept on each point, which leaves them out of order. Enable the re-time option to rewrite timestamps so they increase from a fresh start time, matching the new direction. Q: Is elevation preserved? A: Yes. Each point keeps its ele value, so a reversed climb correctly becomes a descent and vice versa in any tool that reads the file. Q: Does this work for out-and-back routes? A: Yes — that is the main use case. Reverse the outbound leg to get a ready-made return route without re-recording it. Q: Is my route uploaded? A: No. The file is parsed and reversed entirely in your browser using the built-in XML parser, so your GPS data never leaves your machine. #### GPX Splitter URL: https://geratools.com/gpx-splitter Divide one large GPX track into several smaller GPX files — split every N points, on time gaps above a threshold, or at calendar-day boundaries. All logic runs in your browser with no upload. How to use: 1. Load the GPX: Paste the GPX contents or choose a .gpx file from your device. 2. Pick a split rule: Choose to split every N track points, on time gaps over a chosen number of minutes, or by calendar day. 3. Get the pieces: Click Split to produce one valid GPX document per part, each with its own point count. FAQ: Q: What split modes are available? A: Three: every N points (fixed-size chunks), by time gap (start a new part whenever the gap between two points exceeds your threshold), and by date (a new part per calendar day in the timestamps). Q: Does time-gap or date splitting need timestamps? A: Yes. Those two modes read the time element on each track point. If your file has no timestamps, use the every-N-points mode instead. Q: Are the output files valid GPX? A: Yes. Each part is wrapped in a complete GPX 1.1 document with a single track and segment, so every piece opens in any GPX-aware app on its own. Q: Is my track uploaded? A: No. The file is parsed and split entirely in your browser using the built-in XML parser — your GPS data never leaves your device. Q: What happens to elevation and time on each point? A: Each track point is copied verbatim, including its ele and time children, so no elevation or timing information is lost in the split. #### GPX Track Simplifier URL: https://geratools.com/gpx-track-simplifier Apply the Ramer-Douglas-Peucker algorithm to a GPX track with a configurable epsilon (in metres) to cut point count while preserving route shape. Shows before and after point counts and a downloadable simplified GPX. Fully in-browser. How to use: 1. Paste your GPX: Paste the contents of a .gpx file containing one or more track segments. 2. Set the tolerance: Choose an epsilon in metres — larger values remove more points and flatten more detail. 3. Download the result: Review the new point count, then copy or download the simplified GPX. FAQ: Q: What does the epsilon value mean? A: Epsilon is the maximum distance, in metres, that any removed point may sit from the simplified line. A point is kept only if dropping it would move the route by more than epsilon, so a larger epsilon removes more points. Q: How is distance measured on the globe? A: The tool projects latitude and longitude onto a local equirectangular plane scaled by metres-per-degree at the track's latitude, then measures perpendicular distance there. This keeps the perpendicular distance test accurate for typical track extents. Q: Does it keep elevation and timestamps? A: Yes. Each surviving point retains its original elevation and time tags exactly as they appeared, so the simplified track stays compatible with tools that read ele and time. Q: Are the first and last points always kept? A: Yes. Ramer-Douglas-Peucker is anchored on the endpoints of each segment, so the start and finish of every track segment are never removed regardless of epsilon. Q: Is my GPX uploaded? A: No. Parsing, simplification, and re-serialisation all happen in your browser using the DOMParser API. The file never leaves your device. #### GPX Viewer URL: https://geratools.com/gpx-viewer Load a GPX file and see the route plotted as a scalable track map with an elevation profile, total distance, point count and bounding box. Parsing runs entirely in your browser, so your GPS data never leaves your machine. How to use: 1. Paste or load your GPX: Paste the contents of a .gpx file into the input box, or choose a file from your device. 2. Render the track: Click Render to plot every track point as a scaled path with the start and end marked. 3. Read the stats: Review total distance, point count, elevation range and the elevation profile beneath the map. FAQ: Q: Does this upload my GPS track? A: No. The GPX is parsed in your browser using the built-in XML parser and drawn locally — none of your coordinates are sent to a server. Q: Why is the map a line drawing rather than satellite tiles? A: To stay fully offline and key-free, the track is rendered as a scaled SVG path inside its bounding box rather than over external map tiles. The shape, scale and elevation are accurate. Q: What GPX elements does it read? A: It reads track points (trkpt) across all track segments, plus standalone waypoints (wpt). Latitude, longitude and elevation (ele) attributes are all parsed. Q: How is the distance calculated? A: Distance is the sum of great-circle (Haversine) distances between consecutive track points, which is accurate for the short hops typical of GPS logs. Q: Does it handle multiple tracks or segments? A: Yes. All segments of all tracks are read in order and concatenated into one continuous path for display and distance totals. #### HAR File Viewer URL: https://geratools.com/har-viewer Free in-browser HAR file viewer. Load an HTTP Archive .har export from your browser DevTools and inspect every request, status, size, timing breakdown (DNS, connect, wait, receive) and headers. Nothing is uploaded. How to use: 1. Export a HAR file: In Chrome or Firefox DevTools, open the Network tab and choose "Save all as HAR with content". 2. Load the .har file: Paste the HAR JSON or pick the .har file with the file chooser. Everything is parsed locally. 3. Inspect the requests: Review the table of requests, sort by time or size, and expand any entry to see headers and timing phases. FAQ: Q: Is my HAR file uploaded anywhere? A: No. The file is read with the browser's FileReader and parsed in JavaScript on your machine. HAR files often contain cookies, auth tokens and request bodies, so keeping them local matters. Q: What is a HAR file? A: HAR (HTTP Archive) is a JSON format that browsers and proxies use to record a full session of HTTP requests and responses, including timing. DevTools can export one for debugging. Q: What do the timing phases mean? A: Each entry has a timings object: blocked (queueing), dns (name lookup), connect (TCP), ssl (handshake), send (uploading the request), wait (server think time / TTFB), and receive (downloading the response). Q: Why are some timing values -1? A: The HAR spec uses -1 to mean a phase was not applicable or not measured. For example a reused keep-alive connection has dns and connect set to -1 because no new connection was opened. Q: Can it show response bodies? A: It shows whatever the HAR includes. If you exported without content the bodies are empty; with content they are stored under each entry's response.content.text and previewed here. #### HTML Form Validation Attributes URL: https://geratools.com/html-form-validation-attributes Reference for HTML5 form validation attributes — required, pattern, min, max, minlength, step — plus the Constraint Validation API methods and ValidityState flags, with a live pattern tester. How to use: 1. Browse the validation attributes: Review each attribute, the input types it applies to and the ValidityState flag it sets when violated. 2. Test a pattern live: Enter a regular expression and a value to see whether the pattern attribute would accept it. 3. Read the Constraint Validation API: Use checkValidity, reportValidity and setCustomValidity to drive validation from JavaScript. FAQ: Q: How does the pattern attribute work? A: pattern holds a JavaScript regular expression that the entire value must match — it is implicitly anchored, so the regex must match the whole string. It applies to text, search, url, tel, email and password inputs and sets the patternMismatch flag when it fails. Q: What is the Constraint Validation API? A: It is the DOM interface for native validation. Each control exposes a validity object (ValidityState), checkValidity() and reportValidity() to trigger checks, and setCustomValidity(message) to inject your own error. An empty custom message marks the field valid again. Q: What is the difference between checkValidity and reportValidity? A: checkValidity() returns a boolean and fires an invalid event but shows no UI. reportValidity() does the same and additionally displays the browser's validation bubble on the first invalid control, focusing it. Q: Why does required behave differently per input type? A: For text-like inputs required means non-empty. For checkboxes it means the box must be checked. For radio groups it means one option in the name group must be selected. For file inputs it means at least one file must be chosen. Q: Is the pattern tester run locally? A: Yes. The regex is compiled and tested in your browser with the same anchoring HTML uses. Nothing is sent to a server. #### iframe sandbox Attribute Tokens URL: https://geratools.com/html-sandbox-tokens Reference for the HTML iframe sandbox attribute tokens including allow-scripts, allow-forms, allow-same-origin, allow-popups and allow-top-navigation, with what each re-enables and the secure default block list. How to use: 1. Pick the capabilities to re-allow: Toggle the sandbox tokens for the features your embedded content genuinely needs, such as allow-scripts or allow-forms. 2. Read the security warnings: Watch for the warning when you combine allow-scripts with allow-same-origin, which lets framed content remove its own sandbox. 3. Copy the iframe attribute: The tool assembles a correctly spaced sandbox attribute you can paste straight into your iframe tag. FAQ: Q: What does an empty sandbox attribute do? A: An empty sandbox (sandbox="") applies the maximum set of restrictions: scripts disabled, forms disabled, the frame forced into a unique opaque origin, popups blocked, top-level navigation blocked, plugins blocked, and more. Each token you add relaxes exactly one restriction. Q: Why is allow-scripts plus allow-same-origin dangerous? A: When both are present, the framed document runs scripts and shares the embedder's origin, so it can reach into the parent's DOM and even script-remove its own sandbox attribute. That combination effectively defeats the sandbox, so only use it for content you fully trust. Q: Does sandbox replace the need for a Content Security Policy? A: No. sandbox restricts the framed document's capabilities, while CSP controls what resources a page may load and where. They are complementary layers. A hardened embed typically uses both a tight sandbox and a restrictive CSP. Q: What is allow-top-navigation for? A: By default a sandboxed frame cannot navigate the top-level browsing context, which stops framed ads or content from redirecting the whole page. allow-top-navigation re-enables that; allow-top-navigation-by-user-activation only permits it in response to a real user gesture, which is safer. Q: Are sandbox tokens space-separated or comma-separated? A: Space-separated, like class names. The attribute looks like sandbox="allow-scripts allow-forms". Commas are not valid and will be treated as part of the token text, silently disabling the affected tokens. #### HTTP 2xx Success Codes URL: https://geratools.com/http-2xx-codes Focused, searchable reference for HTTP 200–299 success status codes covering body rules, key headers, idempotency notes and when each applies in REST and WebDAV APIs. How to use: 1. Search a code: Type a number like 201 or a phrase like "no content" into the search box. 2. Read the semantics: Each card explains the meaning, expected body, and idempotency for the method. 3. Apply it: Pick the most specific 2xx code for your response instead of always returning 200. FAQ: Q: What is the difference between 200 and 201? A: 200 OK is a generic success where the body holds the result. 201 Created specifically means a new resource was created and should carry a Location header pointing to it, typically after POST or PUT. Q: When should I use 204 No Content? A: Use 204 when the request succeeded but there is nothing to return, such as a successful DELETE or an update with no echoed body. A 204 response must not include a message body. Q: What is 206 Partial Content for? A: 206 is returned when the server fulfils a Range request and sends only part of the resource. It powers resumable downloads and media seeking, and includes a Content-Range header. Q: Are 2xx responses cacheable? A: Many are cacheable by default for safe methods like GET, but caching ultimately depends on Cache-Control, ETag, and the request method. Always set explicit cache headers for predictability. Q: What is 202 Accepted? A: 202 means the request was accepted for asynchronous processing but is not complete. The body usually points to a status resource the client can poll for the eventual outcome. #### HTTP 4xx Client Error Codes URL: https://geratools.com/http-4xx-codes Searchable reference for HTTP 400–499 client error codes covering meaning, common root causes, required headers and REST API best practices for 400, 401, 403, 404, 409, 422 and 429. How to use: 1. Search an error: Type a code like 403 or a phrase like "rate limit" to filter the list. 2. Read the cause: Each card lists the meaning plus the most common reasons the error is returned. 3. Return the right one: Map your API failures to the most specific 4xx code and include the required headers. FAQ: Q: What is the difference between 401 and 403? A: 401 Unauthorized means authentication is missing or failed, so the client should re-authenticate and must receive a WWW-Authenticate header. 403 Forbidden means the identity is known but lacks permission, so re-authenticating will not help. Q: When should I use 422 instead of 400? A: Use 400 when the request is syntactically malformed, such as broken JSON. Use 422 Unprocessable Content when the syntax is valid but the data fails business or validation rules, like a missing required field value. Q: What headers must a 429 include? A: A 429 Too Many Requests response should include a Retry-After header telling the client how long to wait before retrying. Many APIs also add rate-limit headers describing the remaining quota and reset time. Q: Is 404 the right code for an unauthorized resource? A: Sometimes. To avoid revealing that a resource exists to users who cannot access it, APIs may return 404 instead of 403. This is a deliberate information-hiding choice rather than a true not-found. Q: What does 409 Conflict mean? A: 409 indicates the request conflicts with the current state of the resource, such as an edit conflict, a version mismatch, or violating a uniqueness constraint. The body should explain how to resolve the conflict. #### HTTP Authentication Schemes URL: https://geratools.com/http-authentication-schemes Searchable reference for HTTP authentication scheme names used in the Authorization and WWW-Authenticate headers, including Basic, Bearer, Digest, Negotiate, NTLM and SCRAM, with syntax, RFC and security guidance. Bundled offline. How to use: 1. Search a scheme: Type a scheme name like Bearer or Digest, or a keyword such as kerberos or token. 2. Read the syntax: Each entry shows the header form, the defining RFC, what the scheme does and its security caveats. 3. Pick the right one: Use the security notes to choose — for example Bearer over TLS for APIs, or Negotiate for Windows single sign-on. FAQ: Q: What is the difference between Basic and Bearer authentication? A: Basic sends a base64-encoded username and password on every request, so it must run over TLS. Bearer sends an opaque or JWT token issued by an authorization server; anyone holding the token can use it until it expires, so short lifetimes and TLS are essential. Q: Is Basic authentication encrypted? A: No. Basic only base64-encodes the credentials, which is trivially reversible. It provides no confidentiality on its own and must always be carried over HTTPS, where TLS supplies the encryption. Q: How does Digest authentication avoid sending the password? A: Digest is a challenge-response scheme: the server sends a nonce, and the client returns a hash of the username, password, nonce and request details. The password itself never crosses the wire, though weak hash choices like MD5 and the lack of body integrity mean TLS is still preferred. Q: Why is NTLM discouraged in favour of Kerberos? A: NTLM is vulnerable to relay and pass-the-hash attacks and authenticates per-connection rather than per-request. The Negotiate scheme prefers Kerberos, which provides mutual authentication and ticket-based security, and Microsoft now actively deprecates NTLM. Q: Where do I put the scheme name in the request? A: The client sends it in the Authorization header, for example Authorization: Bearer eyJ.... The server advertises which schemes it accepts via the WWW-Authenticate header in a 401 response, or Proxy-Authenticate for a 407. #### Hue Rotation Calculator URL: https://geratools.com/hue-rotate-calculator Free hue rotation calculator — shift a color's hue by any number of degrees around the HSL color wheel and get the rotated hex, RGB, and HSL values with a side-by-side preview. How to use: 1. Enter a base color: Type a hex color such as 2. Set the rotation: Enter a degree offset from -360 to 360. Try 180 for the complementary color. 3. Read the rotated color: The tool converts to HSL, adds your offset to the hue, wraps it to 0–360, and converts back to hex and RGB. FAQ: Q: How does hue rotation work? A: The color is converted from RGB to HSL, the hue (an angle from 0 to 360 degrees) has the offset added to it, the result is wrapped back into the 0–360 range, and the color is converted back to RGB. Saturation and lightness are left unchanged. Q: What does a 180-degree rotation produce? A: Rotating the hue by 180 degrees gives the complementary color — the one directly opposite on the color wheel. Pairs like red and cyan, or blue and orange, are complementary. Q: Why is the result for a grey or black color unchanged? A: Greys, white, and black have zero saturation, so they have no meaningful hue to rotate. Shifting the hue of an achromatic color leaves it looking identical. Q: Does the CSS hue-rotate filter use the same math? A: The CSS filter hue-rotate() uses a luminance-preserving color matrix that differs slightly from a pure HSL hue shift, so results can vary. This tool performs the clean HSL rotation, which is what most palette and design work expects. Q: Is my color sent anywhere? A: No. The conversion and rotation run entirely in your browser. Nothing is uploaded. #### ID3 Tag Viewer & Editor URL: https://geratools.com/id3-tag-viewer Free ID3 tag viewer and editor that reads ID3v1 and ID3v2 frames from MP3 files in your browser, shows title, artist, album, year, genre and track, and writes a new tagged MP3 you can download. No upload. How to use: 1. Load an MP3 file: Drop an MP3 onto the box or click to browse. The file is read locally with FileReader and never leaves your device. 2. Review and edit the tags: The viewer decodes the ID3v2 header and common text frames (TIT2, TPE1, TALB, etc.) and fills an editable form for title, artist, album, year, genre and track. 3. Download the retagged MP3: Edit any field and click Download. A fresh ID3v2.3 tag is written ahead of the audio frames and the new MP3 is offered as a Blob download. FAQ: Q: What is the difference between ID3v1 and ID3v2? A: ID3v1 is a fixed 128-byte block at the very end of the file with short, length-limited fields. ID3v2 sits at the start of the file, uses named frames like TIT2 (title) and TPE1 (artist), supports Unicode and has no practical length limit. This tool reads both and writes ID3v2.3. Q: Does editing change the audio quality? A: No. Tag editing only rewrites the metadata block at the front of the file; the MPEG audio frames are copied byte-for-byte. There is no re-encoding, so the sound is identical to the original. Q: Why does my year or genre show oddly? A: Year is read from the TYER (v2.3) or TDRC (v2.4) frame and genre from TCON, which may contain a numeric code in parentheses like (17) for Rock. The editor shows the raw decoded text so you can correct it directly. Q: Can it read embedded album artwork? A: It detects the presence of an APIC (attached picture) frame and reports its size and MIME type. Full artwork rendering and replacement are intentionally out of scope to keep the tool dependency-free and fast. Q: Is my file uploaded anywhere? A: No. All parsing and tag writing happen entirely in your browser using FileReader and Blob. Nothing is sent to a server, so the tool works offline once loaded. #### IEEE-754 Float32 Inspector URL: https://geratools.com/ieee-754-float32-inspector Inspect any 32-bit IEEE-754 float: see the exact stored value, the binary bit layout, the sign bit, the 8-bit biased exponent, and the 23-bit mantissa, plus its category (normal, subnormal, infinity, NaN). Runs entirely in your browser. How to use: 1. Enter a decimal number: Type the value you want to inspect, such as 0.15625 or -42.5. It is first rounded to the nearest representable 32-bit float. 2. Read the bit layout: The colored bit string shows the sign, the 8 exponent bits and the 23 mantissa bits separated for clarity. 3. Review the decoded fields: The table breaks out the stored value, category, sign, raw and unbiased exponent, mantissa and the full 32-bit hex pattern. FAQ: Q: What is the IEEE-754 single-precision format? A: It is the 32-bit floating-point standard (binary32) used by most languages for the float type. It splits 32 bits into 1 sign bit, 8 exponent bits and 23 mantissa (fraction) bits. Q: What is the exponent bias? A: The 8-bit exponent is stored with a bias of 127, meaning the true exponent equals the stored value minus 127. This lets the field represent both positive and negative exponents without a separate sign. Q: What is the implicit leading bit? A: For normal numbers the mantissa has an implied leading 1 that is not stored, giving 24 bits of precision from only 23 stored bits. Subnormal numbers instead use an implied leading 0. Q: What are subnormals, infinity and NaN? A: When the exponent field is all zeros the value is zero or subnormal; when it is all ones the value is infinity (zero mantissa) or NaN (nonzero mantissa). These special cases let the format represent gradual underflow and undefined results. Q: Why does my entered value change slightly? A: A 32-bit float cannot represent every decimal exactly, so the tool first rounds to the nearest representable value (round-to-nearest-even). The stored value line shows what is actually held in the bits. #### IEEE-754 Float64 Inspector URL: https://geratools.com/ieee-754-float64-inspector Free IEEE-754 double-precision (binary64) inspector. Enter any decimal and see its exact sign bit, 11-bit biased exponent, 52-bit mantissa, hex pattern and classification. Runs entirely in your browser. How to use: 1. Enter a number: Type any decimal value, scientific notation like 1e308, or special values such as Infinity and NaN. 2. Read the bit fields: The tool extracts the exact 64 bits the CPU stores and breaks them into the sign bit, biased exponent and 52-bit mantissa. 3. Inspect the layout: Review the hex pattern and the colour-coded full bit string to see precisely how the value is encoded. FAQ: Q: How is a double-precision float laid out? A: A 64-bit IEEE-754 double uses 1 sign bit, 11 exponent bits and 52 mantissa bits. The exponent is biased by 1023, and normalized numbers carry an implicit leading 1 in the mantissa. Q: What is the exponent bias? A: The 11-bit exponent field stores a biased value: the true exponent equals the stored value minus 1023. This lets the field represent exponents from -1022 to +1023 without a separate sign bit. Q: Why does 0.1 not have a clean bit pattern? A: 0.1 has no exact binary fraction, so it is rounded to the nearest representable double. The inspector shows the actual stored bits, which is why 0.1 + 0.2 famously does not equal exactly 0.3. Q: What are subnormal numbers? A: When the exponent field is all zeros but the mantissa is non-zero, the number is subnormal (denormalized). These represent values smaller than the smallest normalized double, with reduced precision. Q: Is my input sent anywhere? A: No. The bit extraction uses a DataView in your browser and nothing is transmitted. The tool is fully client-side and privacy-first. #### IntelliJ IDEA Keyboard Shortcuts URL: https://geratools.com/intellij-keyboard-shortcuts A searchable IntelliJ IDEA keymap reference for the macOS and Windows/Linux default keymaps, covering search, navigation, editing, refactoring and run/debug shortcuts with descriptions. How to use: 1. Choose a keymap: Select the macOS or Windows/Linux default keymap so the shortcut column matches your setup. 2. Search an action: Type an action like rename or run, or a key combination, to filter the table. 3. Filter by group: Choose a group such as Navigation, Editing, Refactor or Run/Debug to narrow the list. FAQ: Q: What is Search Everywhere and how do I open it? A: Search Everywhere finds classes, files, symbols, actions and settings from one box. Open it by pressing Shift twice in quick succession. It is the fastest way to reach anything in the IDE without remembering a specific shortcut. Q: How do I show context actions and quick fixes? A: Press Alt+Enter (Option+Return on macOS) on a highlighted symbol or error. IntelliJ offers intentions, quick fixes and refactorings relevant to the code under the caret, such as importing a class or generating missing methods. Q: Does IntelliJ have a single refactor shortcut? A: Yes. Refactor This (Ctrl+Alt+Shift+T on Windows/Linux, Ctrl+T on macOS) opens a menu of every refactoring available at the caret, including rename, extract method, extract variable and inline, so you do not have to memorise each one. Q: Do JetBrains IDEs share this keymap? A: Largely yes. PyCharm, WebStorm, GoLand, Rider and the other JetBrains IDEs use the same default keymap as IntelliJ IDEA, so most of these shortcuts carry across. A few language-specific actions differ between products. Q: Is anything I search uploaded? A: No. The shortcut list and the search run entirely in your browser. Nothing you type is sent to any server. #### Invisible Character Stripper URL: https://geratools.com/invisible-char-strip Strip invisible Unicode characters such as zero-width spaces (U+200B), soft hyphens (U+00AD), byte-order marks (U+FEFF) and directional marks from text. Reports each one removed. Runs entirely in your browser. How to use: 1. Paste your text: Enter or paste the text you suspect contains hidden or zero-width characters into the input box. 2. Read the cleaned output: The tool removes every invisible character and shows the cleaned text ready to copy. 3. Check what was removed: The findings list reports each invisible character by position, code point, and name. FAQ: Q: What counts as an invisible character? A: These are code points that produce no visible glyph but still occupy a position in the string, such as the zero-width space (U+200B), zero-width joiner (U+200D), soft hyphen (U+00AD), byte-order mark (U+FEFF), and bidirectional formatting marks. Q: Why do invisible characters cause problems? A: They silently break string comparison, search, and JSON parsing, and they can hide watermarks or tracking fingerprints in copied text. Two strings that look identical may not be equal because one contains a hidden zero-width character. Q: What happens to no-break spaces? A: The no-break space (U+00A0) is converted to an ordinary space rather than deleted, because it usually represents intended spacing. Every other invisible character in the list is removed entirely. Q: Does it remove ordinary spaces, tabs, or line breaks? A: No. Visible whitespace such as regular spaces, tabs, and newlines is preserved. Only zero-width and formatting characters that carry no visible glyph are stripped. Q: Is my text sent to a server? A: No. The stripping runs entirely in your browser, so nothing you paste is uploaded, logged, or stored anywhere. #### IP Protocol Numbers URL: https://geratools.com/ip-protocol-numbers IANA IP protocol number reference for the IPv4 Protocol field and IPv6 Next Header value, covering TCP, UDP, ICMP, OSPF, GRE, ESP, AH, SCTP and more with the defining RFC. Bundled offline. How to use: 1. Enter a number or name: Type a protocol number like 6, or a keyword such as tcp, esp, gre or ospf. 2. Read the match: Each result shows the assigned number, the IANA keyword, the full protocol name and its reference RFC. 3. Use it in filters: Apply the number where the IP header is matched — for example proto 47 for GRE in a firewall or capture filter. FAQ: Q: Is an IP protocol number the same as a port number? A: No. The protocol number is an 8-bit field in the IP header that names the next-layer protocol, such as 6 for TCP or 17 for UDP. Port numbers belong to TCP and UDP themselves and identify the application endpoint. Q: Where does the protocol number live in IPv6? A: IPv6 has no Protocol field. The same values appear in the Next Header field of the IPv6 base header (and of each extension header), forming a chain that ends at the upper-layer protocol. Q: What protocol numbers do IPsec tunnels use? A: IPsec uses protocol 50 for the Encapsulating Security Payload (ESP) and protocol 51 for the Authentication Header (AH). Firewalls must permit these numbers directly, not just UDP/TCP ports, unless NAT-Traversal wraps ESP in UDP 4500. Q: Why is OSPF assigned its own protocol number? A: OSPF runs directly over IP as protocol 89 rather than over TCP or UDP, so it carries no port. Routers identify and filter OSPF traffic by this protocol number. Q: What is protocol number 41 used for? A: Protocol 41 is IPv6 encapsulation — it carries an IPv6 packet inside an IPv4 packet, the basis of 6in4 tunnels used to reach IPv6 over an IPv4-only path. #### ISO 3166-2 Country Subdivision Lookup URL: https://geratools.com/iso3166-2-subdivision-lookup Search ISO 3166-2 codes for administrative subdivisions — states, provinces, regions, and territories — within any country. Filter by country, subdivision name, or code to find the exact standardized identifier. How to use: 1. Pick a country: Select a country to see all of its ISO 3166-2 subdivisions, or leave it on all countries. 2. Search by name or code: Type a subdivision name, an ISO code like US-CA, or a category such as province to filter results. 3. Copy the code: Each result shows the full hyphenated ISO 3166-2 code, the subdivision name, and its category. FAQ: Q: What is an ISO 3166-2 code? A: ISO 3166-2 is the international standard for codes that identify principal administrative subdivisions of countries — states, provinces, regions, cantons, and similar. Each code starts with the ISO 3166-1 alpha-2 country code, a hyphen, then one to three letters or digits, for example US-CA for California. Q: How does ISO 3166-2 relate to ISO 3166-1? A: ISO 3166-1 gives each country a two-letter code (US, GB, FR). ISO 3166-2 builds on it by appending a subdivision suffix after a hyphen. So GB is the United Kingdom and GB-SCT is Scotland. The country prefix is always the alpha-2 code. Q: Why do some codes use numbers and others use letters? A: Each country chooses its own subdivision suffix scheme. Many use letter abbreviations (US-NY), while others use numeric codes derived from local administrative numbering (FR-75 for Paris, IT-RM for Rome). Both are valid within the standard. Q: What does the category field mean? A: ISO 3166-2 labels each subdivision with its local administrative type — state, province, region, canton, emirate, district, and so on. The category reflects the country's own constitutional terminology rather than a single global word. Q: Can subdivision codes change? A: Yes. ISO publishes newsletters and updates when countries reorganize their administrative divisions, rename regions, or change codes. Always check against the current ISO Online Browsing Platform for authoritative, up-to-date values. #### ISO 3166 Alpha-2 Country Code Lookup URL: https://geratools.com/iso3166-alpha2-lookup Look up the ISO 3166-1 alpha-2 two-letter country code for any nation, the same codes used in country domains, locale tags, and APIs. Search by code or country name and see the matching alpha-3 and numeric codes too. How to use: 1. Enter a code or country: Type a 2-letter code such as GB, or a country name such as United Kingdom. 2. Read the result: The tool lists each matching country with its alpha-2 code plus the related alpha-3 and numeric codes. 3. Use the code: Copy the 2-letter code into a domain, locale tag, or API field that expects ISO 3166-1 alpha-2. FAQ: Q: What is an ISO 3166-1 alpha-2 code? A: It is the two-letter country code defined by the ISO 3166 standard, such as GB for the United Kingdom or US for the United States. It is the most widely used country code, appearing in country domains, language tags, and countless APIs. Q: Is the alpha-2 code the same as the country internet domain? A: Almost always, yes. Country-code top-level domains are based on ISO 3166-1 alpha-2 codes, so .fr is France and .de is Germany. The notable exception is the United Kingdom, whose code is GB but whose domain is .uk for historical reasons. Q: Why does the United Kingdom use GB and not UK? A: ISO 3166 assigns GB to the United Kingdom of Great Britain and Northern Ireland. UK is exceptionally reserved by ISO but is not the official code, although the .uk domain uses it. For data interchange, use GB. Q: How is alpha-2 different from alpha-3 and numeric codes? A: All three identify the same country. Alpha-2 is two letters (GB), alpha-3 is three letters (GBR) and is more readable, and the numeric code (826) is language-independent. Use whichever your system requires. Q: Does the search send my input anywhere? A: No. The full country table is built into the tool and the search runs entirely in your browser, so nothing you type is transmitted. #### ISO 3166 Alpha-3 Country Code Lookup URL: https://geratools.com/iso3166-alpha3-lookup Resolve the ISO 3166-1 alpha-3 three-letter country code for any nation, the codes printed in passports and used across banking, sport, and data systems. Search by code or name and see the related alpha-2 and numeric codes. How to use: 1. Enter a code or country: Type a 3-letter code such as GBR, or a country name such as United Kingdom. 2. Read the result: The tool lists each matching country with its alpha-3 code plus the related alpha-2 and numeric codes. 3. Use the code: Copy the 3-letter code into a passport, banking, or database field that expects ISO 3166-1 alpha-3. FAQ: Q: What is an ISO 3166-1 alpha-3 code? A: It is the three-letter country code from the ISO 3166 standard, such as GBR for the United Kingdom or USA for the United States. The extra letter makes it more readable and mnemonic than the two-letter code, which is why passports and many databases use it. Q: Where are alpha-3 codes used? A: They appear in machine-readable passports, international banking, the Olympics and other sport, and large datasets where readability matters. The World Bank and many statistical agencies key country data on alpha-3 codes. Q: How is alpha-3 different from alpha-2? A: Both identify the same country, but alpha-3 uses three letters (GBR) and alpha-2 uses two (GB). Alpha-3 is more self-explanatory, while alpha-2 is shorter and underpins country internet domains. They are not interchangeable in a field that specifies one or the other. Q: Are alpha-3 codes always derived from the country name? A: Often but not always. Many are intuitive abbreviations like FRA for France or DEU for Germany, where the code reflects the local name Deutschland. Others, such as CHE for Switzerland from the Latin Confoederatio Helvetica, are less obvious, so a lookup is useful. Q: Does this tool need an internet connection? A: No. The full country table is built into the tool and the search runs in your browser, so it works offline and transmits nothing. #### ISO 3166-3 Formerly Used Country Codes URL: https://geratools.com/iso3166-formerly-used-codes Searchable reference of ISO 3166-3 codes for countries that no longer exist. Look up the 4-letter codes for the USSR, Czechoslovakia, Yugoslavia, Zaire, Burma and more, with successor states and withdrawal year. How to use: 1. Search the table: Type a former country name or any of its codes to filter the list instantly. 2. Read the alpha-4 code: The bold 4-letter code is the ISO 3166-3 identifier you use for the dissolved country. 3. Check the successor: The successor column shows what the territory became, so you can map old records to current codes. FAQ: Q: What is ISO 3166-3? A: ISO 3166-3 is the part of the ISO 3166 standard that assigns codes to countries that have been deleted from ISO 3166-1, usually because they merged, split, or changed name. It preserves historical data without reusing a code that now belongs to a different country. Q: Why are the codes four letters instead of two? A: Each ISO 3166-3 code combines the country's former alpha-2 code with the successor's alpha-2 code, for example SUHH for the USSR. A four-letter code avoids clashing with the two-letter codes still in active use. Q: What do the suffixes HH and AA mean? A: HH is used when a country split into several states with no single successor, such as CSHH for Czechoslovakia. AA marks a pure name change where the territory and successor are effectively the same. Q: Can ISO 3166-1 alpha-2 codes be reused after a country disappears? A: Yes, but only after a long quarantine period. ISO 3166-3 exists precisely so that data tagged with the original code is not confused with the new owner of a reassigned code. Q: Is this list exhaustive? A: This covers the main and most frequently referenced ISO 3166-3 entries. The full official register is maintained by the ISO 3166 Maintenance Agency and may include additional minor entries. #### Leading Zeros Counter (CLZ) URL: https://geratools.com/leading-zeros-counter Count the leading zero bits in an integer for a chosen register width — the CLZ operation found on every modern CPU. Enter a value in hex, decimal, or binary, pick 8 to 128 bits, and see the leading zero count and highest set-bit position. Runs in your browser. How to use: 1. Enter the value and base: Choose hex, decimal, or binary and type your integer, for example 0x00010000. 2. Pick the register width: Select 8, 16, 32, 64, or 128 bits to match the register you care about, since leading zeros only make sense for a fixed width. 3. Read the CLZ result: The tool shows the count of leading zeros, the number of significant bits, the zero-padded binary form, and the position of the highest set bit. FAQ: Q: What does CLZ count? A: CLZ, or Count Leading Zeros, returns the number of consecutive zero bits starting from the most significant bit down to the first 1 bit. In a 32-bit register the value 1 has 31 leading zeros. Q: Why does width matter? A: Leading zeros are only meaningful relative to a fixed register size. The same value has more leading zeros in a 64-bit register than in a 32-bit one, so the tool asks you to pick the width explicitly. Q: What is CLZ used for? A: It computes the integer base-2 logarithm (floor of log2 equals width minus CLZ minus one), normalises floating-point mantissas, rounds up to the next power of two, and speeds up priority encoders and big-integer routines. Q: What does CLZ return for zero? A: By convention here a value of zero has all bits zero, so its leading-zero count equals the full register width. Note that some hardware leaves CLZ of zero undefined, so check your platform. Q: What if my number is too big for the width? A: If the value needs more bits than the selected width, it cannot be represented and the tool reports that it does not fit. Increase the width or reduce the value. #### M3U8 / HLS Playlist Parser URL: https://geratools.com/m3u8-parser Parse HLS master and media M3U8 playlists per RFC 8216 — variant streams with bandwidth, resolution and codecs, segment lists with EXTINF durations, EXT-X-KEY encryption, discontinuities and ENDLIST. Runs in-browser; nothing is uploaded. How to use: 1. Provide the playlist: Load a .m3u8 file or paste its contents. The parser detects whether it is a master or media playlist automatically. 2. Read the structure: Master playlists list each variant stream with bandwidth, resolution, and codecs; media playlists list segments with durations. 3. Check the details: Encryption keys, discontinuities, target duration, and whether the playlist is VOD or live are all surfaced. FAQ: Q: What is the difference between a master and a media playlist? A: A master playlist (with EXT-X-STREAM-INF tags) lists the available quality variants and points to a media playlist for each. A media playlist lists the actual .ts or fMP4 segments with their durations. The parser detects which kind you provided. Q: How are segment durations read? A: Each segment is preceded by an #EXTINF:, tag. The parser reads that floating-point duration and sums them to report the total playlist length, matching how players compute it. Q: Does it show encryption information? A: Yes. #EXT-X-KEY tags are parsed for their METHOD (such as AES-128 or SAMPLE-AES) and key URI, so you can see whether and how segments are encrypted. Q: How can I tell live from VOD? A: A media playlist ending with #EXT-X-ENDLIST is video-on-demand (the full segment list is known). Without ENDLIST it is a live playlist that the player would keep refreshing. The parser labels each case. Q: Is anything uploaded? A: No. The file is read as text in your browser and parsed with plain string logic. Nothing is sent to a server, so it works offline and your playlist stays private. #### Magic Number / File Type Detector URL: https://geratools.com/magic-number-detector Free magic-number file type detector. Reads the first bytes of any file in your browser and matches them against dozens of signatures (PNG, JPEG, PDF, ZIP, ELF, MP4 and more), warning when the extension lies. No upload. How to use: 1. Choose a file: Select any file. Only its first 512 bytes are read in your browser; the file is never uploaded. 2. Read the detected type: The tool matches the leading bytes against a signature library and reports the real format and MIME type. 3. Check the extension warning: If the file's extension disagrees with the detected type, a warning flags it as possibly mislabeled or disguised. FAQ: Q: What is a magic number? A: A magic number is a short, fixed byte sequence at the start of a file that identifies its format, such as 89 50 4E 47 for PNG or 25 50 44 46 (%PDF) for PDF. It is far more reliable than the filename extension. Q: Why does it sometimes show several matches? A: Some signatures are shared. A ZIP magic number, for example, also begins DOCX, XLSX, JAR, APK and EPUB files because those are ZIP containers. The tool lists every format that shares the matched bytes. Q: What does the extension-mismatch warning mean? A: If a file named photo.png actually starts with PDF bytes, the content does not match the extension. That can indicate a renamed file, a download error, or a deliberately disguised file, so the tool warns you. Q: Does it read my whole file? A: No. Only the first 512 bytes are read, which is enough for every signature, and that happens in your browser via FileReader. Your file's contents never leave your device. Q: Why did my file not match anything? A: Plain text, CSV, HTML and many source files have no fixed magic number, so they will not match. Uncommon or proprietary formats may also be missing from the signature library. #### MessagePack Viewer URL: https://geratools.com/messagepack-viewer Free MessagePack decoder and viewer. Paste hex or base64, or upload a binary file, and see the decoded JSON with int, float, str, bin, array, map and ext types annotated. 100% client-side, no upload. How to use: 1. Choose the format: Select Hex or Base64 to match your MessagePack encoding, or upload a binary .msgpack file directly. 2. Paste the bytes: Paste the data into the box. On hex input, spaces, commas and a leading 0x are ignored. 3. Decode: Press Decode to JSON to see the structured result with binary blobs and extension types clearly annotated. FAQ: Q: What is MessagePack? A: MessagePack (msgpack) is a compact binary serialization format that is roughly a drop-in faster, smaller alternative to JSON. It is common in Redis tooling, RPC systems, game networking and high-throughput APIs. Q: How are binary and extension types shown? A: Raw binary (bin) values are rendered as bin:0x followed by their hex bytes, and extension types appear as ext(type=n):0x… so you can see both the extension code and its payload without losing data. Q: Does it handle all MessagePack types? A: Yes. It decodes fixint, fixstr, fixmap and fixarray short forms plus str/bin/array/map 8/16/32, the full uint and int range, float 32/64, nil, booleans, and fixext and ext blocks. Q: Is my data uploaded to a server? A: No. The decoder is pure JavaScript that runs in your browser using the built-in DataView and TextDecoder, so nothing you paste or upload ever leaves your device. Q: Why are some big integers slightly off? A: JavaScript numbers are 64-bit floats, so integers beyond 2 to the 53 lose precision. The decoder reads 64-bit ints correctly but converts them to numbers for JSON display, which can round very large values. #### MIC Stock Exchange Code Lookup URL: https://geratools.com/mic-stock-exchange-lookup Look up ISO 10383 MIC codes for global stock exchanges and trading venues. Search by exchange name, city, country, or 4-letter code, and see the operating MIC versus segment MIC distinction. How to use: 1. Search the directory: Type an exchange name, city, country, or 4-letter MIC to filter the list of major trading venues. 2. Read the match: Each result shows the MIC, the exchange name, its city and country, and whether it is an operating or segment MIC. 3. Use the code: Copy the 4-letter MIC for trade reporting, market data feeds, FIX messages, or regulatory filings. FAQ: Q: What is a MIC code? A: A Market Identifier Code is a 4-character ISO 10383 code that uniquely identifies a securities trading exchange or venue worldwide. It is maintained by SWIFT as the registration authority and used in trade reporting, market data, and FIX protocol messages. Q: What is the difference between an operating MIC and a segment MIC? A: An operating MIC identifies the entity that runs one or more markets, while a segment MIC identifies a specific market or order book within it. For example XNYS is the New York Stock Exchange operating MIC, and it has segment MICs for its different platforms. Q: Why do MIC codes often start with X? A: By convention many exchange MICs begin with X followed by a city or country abbreviation, such as XLON for London and XTKS for Tokyo. The X is not mandatory, but it is the historical pattern for primary exchanges. Q: Are dark pools and ATSs assigned MICs? A: Yes. ISO 10383 covers all regulated trading venues, including alternative trading systems, dark pools, and multilateral trading facilities, not just lit stock exchanges. Each gets its own MIC for transparent trade reporting. Q: How current is this MIC list? A: MIC codes change as venues open, merge, or close, and the official list is updated monthly by SWIFT. Treat this as a reference for major venues and confirm against the official ISO 10383 registry before regulatory use. #### MP3 / Audio Silence Detector URL: https://geratools.com/mp3-silence-remover Decode an MP3, WAV, or OGG with the Web Audio API and scan PCM samples for sub-threshold runs, reporting the exact timestamps and total duration of every silent gap. Runs 100% in your browser — no upload. How to use: 1. Choose an audio file: Pick an MP3, WAV, OGG, or M4A file. It is decoded locally with the Web Audio API and never leaves your browser. 2. Set the threshold: Adjust the dBFS threshold and minimum silence length so only genuine gaps (not quiet passages) are flagged. 3. Read the timestamps: Each silent segment is listed with its start, end, and duration so you can trim or split the audio in your editor. FAQ: Q: What does the dBFS threshold mean? A: dBFS (decibels relative to full scale) measures level where 0 dB is the loudest possible sample. A threshold of -50 dBFS treats anything quieter than that as silence; lower (more negative) values are stricter and flag fewer gaps. Q: Does this tool remove the silence? A: It detects and timestamps silent segments rather than re-encoding the file. Use the reported start and end times to trim or split the audio in an editor such as Audacity or ffmpeg. Q: Which file formats work? A: Any format the browser's AudioContext.decodeAudioData can handle — typically MP3, WAV, OGG, FLAC, and M4A/AAC. Support varies slightly by browser. Q: Is my audio uploaded anywhere? A: No. The file is read into an ArrayBuffer and decoded entirely in your browser. Nothing is sent to a server, so it works offline and keeps your audio private. Q: Why does increasing the minimum length show fewer segments? A: Short dips below the threshold (between words, for example) are usually not real pauses. The minimum length filter discards any silent run shorter than the value you set, leaving only meaningful gaps. #### Notion Keyboard Shortcuts URL: https://geratools.com/notion-shortcuts Searchable Notion keyboard shortcut reference covering block editing, page actions, markdown triggers and the slash command menu, with keys shown for both macOS and Windows. How to use: 1. Search for an action: Type what you want to do, such as bold, search, or heading. The table filters to matching shortcuts as you type. 2. Pick your platform: Switch between macOS and Windows/Linux so the Mod key renders as Cmd or Ctrl and Alt renders as Option or Alt correctly. 3. Filter by category: Narrow to Editing, Navigation, Markdown, Slash and blocks, or Page actions to scan a focused group of shortcuts. FAQ: Q: How do I open the slash command menu in Notion? A: Type a forward slash (/) at the start of an empty line or anywhere in a block. A menu appears with every block type and command. Keep typing to filter it, for example /todo or /table, then press Enter. Q: What is the difference between Cmd and Ctrl shortcuts? A: On macOS the modifier key is Cmd; on Windows and Linux it is Ctrl. The shortcuts are otherwise identical. Use the platform selector so every shortcut shows the correct key for your machine. Q: How do I turn an existing block into another type? A: Select the block by pressing Esc, then type a slash command, or hover the block and use the six-dot handle then Turn into. Markdown triggers like # or - only convert empty blocks as you type at the start. Q: Do markdown shortcuts work everywhere in Notion? A: Markdown triggers such as # for a heading or - for a bullet work at the start of an empty block. Inline markdown like wrapping text in asterisks for bold also works while typing. They do not retroactively convert text you have already styled. Q: Are these shortcuts the same on the Notion mobile app? A: Mobile relies mostly on the slash menu and the formatting toolbar rather than keyboard chords, so many desktop shortcuts do not apply. This reference targets the Notion desktop app and web client where a physical keyboard is available. #### OAuth 2.0 Error Codes URL: https://geratools.com/oauth-error-codes Searchable reference for OAuth 2.0 and OpenID Connect error codes across authorization, token, resource-server and device-flow endpoints, with the meaning and RFC source of each. How to use: 1. Search an error: Type a code like invalid_grant or a keyword like "device" to filter the list. 2. Note the endpoint: Each card shows which endpoint emits the error so you know where to look. 3. Fix the request: Read the description and spec source to correct the client request or flow. FAQ: Q: What does invalid_grant mean in OAuth? A: invalid_grant is returned by the token endpoint when the authorization code or refresh token is expired, revoked, already used, or does not match the client or redirect URI. It usually means the client must restart the authorization flow. Q: How is invalid_client different from invalid_grant? A: invalid_client means client authentication itself failed — unknown client, wrong secret, or unsupported auth method — and often returns HTTP 401. invalid_grant means the client authenticated fine but the grant it presented is no longer valid. Q: What are interaction_required and login_required? A: These OpenID Connect errors occur when a client requests prompt=none for a silent flow but the user must actually interact — login_required means they are not authenticated, and interaction_required means some interaction such as consent is needed. Q: What do authorization_pending and slow_down mean? A: These belong to the OAuth device flow. authorization_pending means the user has not finished approving yet, so keep polling. slow_down means you are polling too fast and should add 5 seconds to your interval. Q: What HTTP status accompanies insufficient_scope? A: A resource server returns 403 Forbidden with insufficient_scope when a valid token lacks the scope required for the resource. The WWW-Authenticate header should name the missing scope so the client can request it. #### OGG / Vorbis Metadata Viewer URL: https://geratools.com/ogg-metadata-viewer Parse the OGG container page structure and the Vorbis comment header with DataView to read TITLE, ARTIST, ALBUM, DATE, and the encoder vendor string from .ogg files. Fully client-side — no audio is uploaded. How to use: 1. Select an OGG file: Choose a .ogg or .oga Vorbis audio file. Only the first part of the file is read, entirely in your browser. 2. Parse the tags: The tool walks the OGG pages, finds the Vorbis comment header, and decodes each KEY=VALUE comment. 3. Review the metadata: The encoder vendor and every tag — title, artist, album, date, and any custom fields — are displayed in a table. FAQ: Q: What are Vorbis comments? A: Vorbis comments are the metadata tags stored in OGG audio, written as KEY=VALUE pairs such as TITLE=Song or ARTIST=Band. Unlike ID3 in MP3, the field names are free-form UTF-8 text, so files may contain custom tags too. Q: How does the parser find the tags? A: It walks the OGG container's pages — each begins with the OggS capture pattern and a segment table — concatenates the payloads, then locates the Vorbis comment header (byte 0x03 followed by 'vorbis') and reads the length-prefixed comment strings. Q: Why might no tags appear? A: The file may be untagged, may use a non-Vorbis codec inside OGG (such as Opus, which uses a similar but different OpusTags header), or may be truncated. The vendor string still shows if the comment header was found. Q: Is my audio uploaded? A: No. Only the first 256 KB of header bytes are read with DataView, and parsing happens entirely in your browser. Nothing is sent to a server. Q: Does it handle Unicode tags? A: Yes. Vorbis comments are UTF-8 by specification, and the tool decodes them with TextDecoder, so accented characters and non-Latin scripts display correctly. #### OpenTelemetry Semantic Conventions URL: https://geratools.com/opentelemetry-semantic-conventions Searchable OpenTelemetry semantic convention attribute reference with namespace, type and stability status. Look up the canonical OTel attribute key for traces, metrics and logs. How to use: 1. Search for an attribute: Type a key or keyword such as http.request.method, db.system, or exception to filter the convention list. 2. Filter by namespace: Use the namespace dropdown to focus on HTTP, Database, RPC, Messaging, Network, or Resource attributes. 3. Apply the canonical key: Read the type and stability status, then set the exact attribute key on your spans, metrics, or logs. FAQ: Q: What are OpenTelemetry semantic conventions? A: They are a standardized set of attribute names and values for telemetry data so that traces, metrics and logs from different systems are consistent and queryable. For example, every HTTP server span uses http.request.method rather than a custom per-vendor key. Q: Why did http.method change to http.request.method? A: The HTTP conventions were stabilized in a way that namespaced request and response attributes. Older instrumentation used http.method and http.status_code; the stable versions are http.request.method and http.response.status_code. Bridge both during migration. Q: What does the stability column mean? A: Attributes are marked Stable, Experimental or Deprecated. Stable attributes will not change name or meaning. Experimental ones may still change, and deprecated ones are superseded by a newer key and should not be used in new code. Q: How do I record an exception on a span? A: Add an event named exception with the attributes exception.type, exception.message and exception.stacktrace. Most SDKs provide a recordException helper that populates these keys automatically from a caught error object. Q: Are these conventions the same for traces and metrics? A: Many attribute keys are shared across signals so you can correlate them, but some conventions are signal-specific. The general resource and span attributes apply broadly, while metric names follow their own naming guidelines layered on the same namespaces. #### PDF Form Field Inspector URL: https://geratools.com/pdf-form-inspector Free PDF form field inspector. Reads the raw PDF bytes in your browser, finds AcroForm text fields, checkboxes, radio groups, choice lists and signatures, and lists each name, type and current value. Useful for form auditing — no PDF is uploaded. How to use: 1. Choose a PDF: Select a PDF that contains an interactive form. The file is read directly in your browser and never uploaded. 2. Read the field table: Each AcroForm field is listed with its name, type (text, checkbox, radio, choice, signature) and current value. 3. Audit before submitting: Check that required fields hold the values you expect and that no hidden field carries stale data. FAQ: Q: What field types can it detect? A: It detects the four AcroForm field types defined in the PDF specification — text (Tx), button (Btn), choice (Ch), and signature (Sig) — and further splits buttons into checkboxes, radio groups, and push buttons using the field flags. Q: How does it read the field values? A: Each form field is a PDF dictionary with an /FT type entry. The tool scans the PDF objects for these dictionaries and pulls the field name (/T), value (/V), flags (/Ff), and tooltip (/TU), decoding PDF literal and hexadecimal strings including UTF-16 text. Q: Why might no fields appear even though the PDF has a form? A: Some PDFs store their objects inside compressed object streams or are encrypted. This lightweight parser does not decompress object streams or decrypt protected files, so it shows a note when an AcroForm is declared but its fields cannot be read directly. Q: Does it modify or fill the PDF? A: No. It is read-only. It inspects and reports the current field names, types, and values so you can audit a form before submitting it, but it does not change anything in the file. Q: Is my PDF uploaded anywhere? A: No. The file is read locally with the browser FileReader API and parsed in JavaScript. The PDF never leaves your device, which is why it is safe for confidential forms. #### PDF Metadata Remover URL: https://geratools.com/pdf-metadata-remover Clear the Title, Author, Subject, Keywords, Creator, Producer, and date fields from a PDF, plus remove the XMP metadata stream, then re-save it. Runs entirely in your browser — documents never reach a server. How to use: 1. Select a PDF: Choose any PDF file. It is loaded and edited locally in your browser with no upload. 2. Review what was found: The tool lists every metadata field that was present, including the XMP packet if one existed. 3. Download the clean file: All Info fields and the XMP stream are cleared, dates are neutralised, and you download the sanitised PDF. FAQ: Q: Which metadata fields are removed? A: Every standard Info dictionary field — Title, Author, Subject, Keywords, Creator, Producer, CreationDate, and ModDate — is cleared, and the XMP metadata stream referenced from the document catalog is deleted. The dates are reset to the Unix epoch so no real authoring time leaks. Q: Does this change the visible content of my PDF? A: No. Only the document's hidden property fields and XMP packet are touched. Pages, text, images, and layout are preserved exactly. Q: Is my PDF uploaded anywhere? A: No. The file is parsed and re-saved in your browser using the pdf-lib library. The document never leaves your device, so confidential files are safe. Q: Why also remove the XMP stream? A: Modern PDFs store metadata twice — once in the legacy Info dictionary and once in an XMP packet. Clearing only the Info fields would leave author and creator data behind in XMP, so both are removed. Q: Will the cleaned file open everywhere? A: Yes. The PDF is re-saved as a standard document with object streams, so it opens in any compliant reader. Only the metadata is gone. #### Periodic Table Element Lookup URL: https://geratools.com/periodic-table-lookup Look up any of the 118 chemical elements by name, symbol, or atomic number. See atomic mass, group, period, category, and full electron configuration with noble-gas core shorthand. Runs in your browser. How to use: 1. Type your search: Enter an element name, its one or two-letter symbol, or its atomic number in the search box. 2. Scan the filtered list: The table narrows live as you type, matching on name, symbol, or atomic number. 3. Read the element data: Each row shows atomic number, symbol, name, standard atomic mass, group, period, and electron configuration. FAQ: Q: How many elements does this cover? A: All 118 confirmed elements, from hydrogen (atomic number 1) through oganesson (118). This includes the synthetic superheavy elements in period 7 that have only been produced in particle accelerators. Q: Where do the atomic masses come from? A: Atomic weights follow the IUPAC 2021 standard atomic weights. For radioactive elements with no stable isotope, the value shown is the mass number of the most stable known isotope rather than a weighted average. Q: What does the electron configuration shorthand mean? A: Configurations use noble-gas core notation. For example, iron is written as [Ar] 3d6 4s2, meaning the argon core plus six 3d and two 4s electrons. This is the standard compact way chemists write configurations. Q: Why is the group blank for some elements? A: Lanthanides and actinides (the f-block) sit outside the numbered groups 1 to 18 in the standard 18-column table, so their group is shown as a dash. Their period is still listed. Q: Can I search by symbol case-insensitively? A: Yes. Searching is case-insensitive, so fe, Fe, and FE all find iron. Two-letter symbols like Na, Cl, and Mg work the same way as single-letter ones. #### PGP / OpenPGP Key Inspector URL: https://geratools.com/pgp-key-inspector Free in-browser OpenPGP key inspector. Paste an armored PGP public or private key and read its User IDs, key ID, full fingerprint, public-key algorithm, creation date and subkeys. Parses RFC 4880 packets locally — nothing is uploaded. How to use: 1. Paste the armored key: Copy the full block including the BEGIN PGP PUBLIC KEY BLOCK and END lines and paste it into the box. 2. Read the key details: The tool de-armors the Base64, parses the OpenPGP packets and shows the primary key's fingerprint, key ID, algorithm and creation date. 3. Review User IDs and subkeys: Check the listed User IDs (name and email) and any encryption or signing subkeys bound to the primary key. FAQ: Q: What is a PGP fingerprint? A: The fingerprint is a hash over the public key packet that uniquely identifies it. For version-4 keys it is the SHA-1 of the key material with a fixed prefix; the last 8 bytes form the short key ID you usually see. Q: Is my key uploaded anywhere? A: No. The armor is decoded and the packets are parsed entirely in your browser. Public keys are meant to be shared, but even a private key block is processed locally and never transmitted. Q: Which algorithms are recognised? A: It maps the public-key algorithm byte to RSA, DSA, ElGamal, ECDH, ECDSA and EdDSA (Ed25519). Unknown algorithm IDs are shown as a numeric code so you can look them up against RFC 4880 / RFC 6637. Q: What are subkeys? A: An OpenPGP key is usually a primary key (used for certification and signing) plus one or more subkeys (often a dedicated encryption subkey). The inspector lists each subkey with its own fingerprint and algorithm. Q: Why is the fingerprint shown for v4 keys only? A: This tool computes fingerprints for version-4 keys, which use a SHA-1 construction this browser can hash with Web Crypto. Legacy v3 keys (rare today) used an MD5 scheme that is not implemented here, so only their basic fields are shown. #### macOS / iOS Plist Viewer URL: https://geratools.com/plist-viewer View Apple property list files in your browser — both XML plists and binary bplist00 files. Renders a readable tree of keys, dictionaries, arrays, dates and data. Parsed locally with no upload, ideal for inspecting app preferences. How to use: 1. Select a plist file: Choose a .plist file. Both XML and binary formats are detected automatically. 2. Let it parse: The tool reads the file locally and decodes its structure into keys and values. 3. Explore the tree: Dictionaries, arrays, dates and data blocks are shown as an indented, readable tree. FAQ: Q: What is the difference between XML and binary plists? A: Both store the same data, but XML plists are human-readable text starting with a tag, while binary plists begin with the magic bytes bplist00 and pack everything compactly. macOS and iOS often store preferences and caches as binary for speed. Q: How is a binary plist decoded? A: A binary plist ends with a 32-byte trailer that records the object count, offset table location and the top object index. The tool reads that trailer, then follows the offset table to decode each typed object — strings, integers, reals, dates, data, arrays and dictionaries. Q: Is my file uploaded? A: No. Parsing happens entirely in your browser using the FileReader API and built-in decoders. App data, which can be sensitive, never leaves your device. Q: How are dates and data blocks shown? A: Dates are decoded from Apple's reference epoch of 1 January 2001 and displayed in ISO-8601, while data blobs are shown as a byte-count placeholder so the tree stays readable rather than dumping raw binary. #### Plug & Socket Type by Country URL: https://geratools.com/plug-socket-type-by-country Look up the standard electrical plug and socket types (Type A through N) used in any country, with the mains voltage and frequency. Find out which travel adapter you need before you go abroad. How to use: 1. Search a country: Type a country name to see which plug and socket types it uses. 2. Filter by plug type: Use the plug-type selector to list all countries that use a given type, A through N. 3. Check before you travel: Each entry shows the plug type letters plus the country's voltage and frequency so you can pick the right adapter. FAQ: Q: How are plug types classified? A: The U.S. International Trade Administration system labels plug and socket designs with letters from Type A through Type N. Type A and B are the flat North American pins, Type C the two-round-pin Europlug, Type G the UK three-rectangular-pin, Type I the Australian angled pins, and so on. Many countries accept more than one type. Q: Do I need an adapter or a converter? A: An adapter only changes the plug shape so it fits the socket — it does not change the voltage. If your device is rated for the destination voltage (most phone and laptop chargers say 100-240V), an adapter is enough. If your device is single-voltage, you also need a voltage converter, or it may be damaged. Q: Why do some countries list multiple plug types? A: Many countries adopted more than one standard over time or accept compatible plugs. For example, much of Europe uses both Type C and Type F sockets, which are physically compatible, and countries like Brazil and Italy mix several types within the same grid. Q: Is Type C the same as Type F? A: They are closely related and largely compatible. Type C is the two-round-pin Europlug used across continental Europe. Type F (Schuko) adds earthing clips and is used in Germany and many neighbours. A Type C plug fits a Type F socket, but a Type F plug will not fit a narrow Type C-only socket. Q: Does plug type tell me the voltage? A: Not by itself, but they correlate. This tool lists the voltage and frequency alongside the plug type so you can check both at once. North American Type A/B regions typically run 120V/60Hz, while Type C/F/G regions usually run 220-240V/50Hz. #### IETF RFC Quick Index URL: https://geratools.com/rfc-index-search Curated, searchable index of important IETF RFCs covering HTTP, DNS, TLS, OAuth, SMTP, and core internet protocols. Find the RFC number, title and status, with a direct link to the official document. How to use: 1. Search by topic or number: Type a technology like TLS, a keyword like cookie, or an RFC number to filter the index. 2. Read the entry: Each result shows the RFC number, title, year, status and a one-line summary of what it standardises. 3. Open the source: Use the link to jump straight to the canonical document on the RFC Editor site for the exact normative text. FAQ: Q: What is an RFC? A: An RFC (Request for Comments) is a numbered document published by the IETF and the RFC Editor that defines internet protocols, procedures and concepts. Despite the name, many RFCs are formal standards that the whole internet relies on, such as the ones for HTTP, TCP and TLS. Q: Do RFC numbers get reused or updated? A: No — each RFC number is permanent and its text is never changed once published. When a protocol is revised, a new RFC is issued that obsoletes the old one. For example HTTP/1.1 moved from RFC 2616 to the RFC 7230 series and then to RFC 9110 through 9112. Q: What do statuses like Standards Track and Informational mean? A: Standards Track RFCs (Proposed Standard, Internet Standard) define protocols meant for interoperable implementation. Informational and Experimental RFCs document ideas or non-normative material. Best Current Practice (BCP) RFCs capture operational and process recommendations. Q: How do I cite the current HTTP specification? A: As of the latest revision, cite RFC 9110 for HTTP semantics, RFC 9111 for caching, and RFC 9112 for HTTP/1.1 message syntax. These obsolete the older RFC 7230 to 7235 set, which in turn obsoleted RFC 2616. Q: Where is the authoritative text for an RFC? A: The canonical source is the RFC Editor at rfc-editor.org, which hosts every RFC in plain text and HTML along with its metadata, errata and obsoletes/updates relationships. This index links there so you always reach the normative version. #### Rust Error Handling Patterns URL: https://geratools.com/rust-error-handling-patterns Reference for Rust error-handling idioms — the ? operator, unwrap and expect, map_err, ok_or, custom Error types, thiserror and anyhow — each with a code example and a note on when to reach for it. How to use: 1. Search the patterns: Type an idiom like map_err or a keyword like library to filter the patterns. Each card shows a code snippet and when to use it. 2. Choose library vs application errors: Compare thiserror for libraries with anyhow for applications to pick the right crate for your context. 3. Avoid panics in production: Read the tradeoff notes to replace unwrap and expect with the ? operator or explicit handling on paths that must not crash. FAQ: Q: What does the ? operator actually do? A: On a Result, ? returns the Ok value or returns early with the Err, converting the error via the From trait into the function's error type. On an Option it returns the Some value or returns None early. The function must itself return a compatible Result or Option. Q: When is unwrap acceptable? A: unwrap is fine in tests, prototypes, and examples, or when you have just proven the value cannot be None or Err. In production code prefer expect with a message explaining the invariant, or propagate the error with ? so a failure does not abort the program. Q: What is the difference between thiserror and anyhow? A: thiserror is for libraries: it derives a structured, typed error enum so callers can match on specific variants. anyhow is for applications: it provides a single boxed error type with context for quick propagation when callers only need to report, not match. Q: How do I add context to an error? A: With anyhow use the .context or .with_context method on a Result to attach a human-readable message that wraps the underlying error. With thiserror, encode context as fields and variants on your error enum and use #[from] for automatic conversions. Q: What does map_err do? A: map_err transforms the Err variant of a Result while leaving Ok untouched. It is the standard way to convert one error type into another before using ?, for example mapping an io::Error into your own domain error. #### SAML 2.0 Status Codes URL: https://geratools.com/saml-status-codes Reference for SAML 2.0 status code URIs covering the Success, Requester, Responder and VersionMismatch top-level codes plus second-level codes like AuthnFailed, NoPassive and RequestDenied. How to use: 1. Search status codes: Type a code name or word such as Responder, AuthnFailed or NoPassive to filter the list. 2. Filter by level: Choose top-level or second-level codes to narrow the reference. 3. Copy the URI: Click Copy URI to grab the full urn:oasis status code value for your logs or config. FAQ: Q: What is a SAML status code? A: It is a URI in the element of a SAML response that reports the outcome of the request. A single top-level StatusCode states success or who is at fault, and an optional nested second-level StatusCode adds the specific reason. Q: What is the difference between Requester and Responder? A: Requester means the failure is the requesting party's fault — usually the service provider sent something malformed or disallowed. Responder means the identity provider itself failed, for example a backend error, independent of the request's correctness. Q: Does a Success status mean the user is authenticated? A: Not by itself. A top-level Success means the protocol exchange completed. You must still inspect the assertion — its AuthnStatement, Conditions (NotBefore/NotOnOrAfter) and AudienceRestriction — to confirm a valid, in-date authentication for your SP. Q: What does NoPassive mean? A: It is returned when the SP requested IsPassive=true (no visible user interaction) but the IdP cannot authenticate the user silently — for instance there is no active session. The SP should retry without IsPassive to allow an interactive login. Q: Where do the status code URIs come from? A: They are defined by the OASIS SAML 2.0 Core specification under the urn:oasis:names:tc:SAML:2.0:status: namespace. Comparing the full URI rather than a short label avoids ambiguity, which is why this tool lets you copy the exact value. #### SI Prefix Table URL: https://geratools.com/si-prefix-table Complete table of the 24 SI metric prefixes with name, symbol, power of ten, and full decimal factor. Covers quetta down to quecto, including the 2022 additions ronna, ronto, quetta, and quecto. Runs in your browser. How to use: 1. Browse or filter: View the full prefix table or type a name, symbol, or power of ten to filter it. 2. Match the prefix: Find the row for the prefix you need and read its symbol, power of ten, and decimal factor. 3. Apply it to a unit: Combine the prefix symbol with a unit symbol, for example k with m to make km (kilometre). FAQ: Q: How many SI prefixes are there? A: There are 24 prefixes covering 20 orders of magnitude in each direction, from quetta (ten to the thirty) down to quecto (ten to the minus thirty). They let you express extremely large and extremely small quantities compactly. Q: What are the newest SI prefixes? A: Ronna, quetta, ronto, and quecto were adopted by the CGPM in November 2022. They were added partly to handle the scale of modern data storage, where global data volumes are now measured in zettabytes and yottabytes. Q: Why is the micro prefix symbol the Greek letter mu? A: Micro is symbolised by the Greek lowercase mu because m was already taken by milli. When mu is unavailable, ASCII contexts sometimes substitute u, but the correct SI symbol is the mu character. Q: Are prefix symbols case-sensitive? A: Yes, strictly. Capital M means mega (a million) while lowercase m means milli (a thousandth). Mixing case changes the value by a factor of a billion, so case matters enormously in scientific and engineering writing. Q: Can prefixes be combined or stacked? A: No. SI rules forbid compound prefixes, so you cannot write millimicro to mean nano. You pick the single prefix nearest the magnitude you need and use it once per unit. #### Sublime Text Keyboard Shortcuts URL: https://geratools.com/sublime-text-shortcuts A complete Sublime Text 3 and 4 keyboard shortcut reference for macOS and Windows/Linux, covering Goto Anything, multiple selections, editing, search and layout with descriptions and a live filter. How to use: 1. Pick your OS: Select macOS or Windows/Linux so the shortcut column shows the matching key combinations. 2. Search an action: Type an action like goto or multiple cursors, or part of a key combination, to filter the list. 3. Filter by group: Choose a group such as Editing, Selection, Search or Layout to focus on related shortcuts. FAQ: Q: What is Goto Anything in Sublime Text? A: Goto Anything (Cmd+P or Ctrl+P) is a fuzzy finder for files in the current project. Type part of a filename to jump to it, add @ to go to a symbol, # to search within the file, or : followed by a line number to jump to that line. Q: How do I select multiple occurrences of a word? A: Press Cmd+D (Ctrl+D on Windows/Linux) to select the word under the cursor and add the next occurrence to the selection. Repeat to keep adding, or press Ctrl+Cmd+G (Alt+F3) to select every occurrence at once. Q: How do I make a column (block) selection? A: Hold the column-select modifier and drag, or use Ctrl+Shift+Up and Ctrl+Shift+Down on macOS to add cursors above and below. This places one cursor on each line so you can edit a vertical block at once. Q: Do these shortcuts apply to Sublime Text 4? A: Yes. Sublime Text 4 keeps the same default key bindings as Sublime Text 3, so this reference applies to both. The Windows column also applies to Linux builds of the editor. Q: Is anything I search uploaded? A: No. The shortcut list and the search run entirely in your browser. Nothing you type leaves your device. #### TAR / TAR.GZ Inspector URL: https://geratools.com/tar-inspector Free TAR and TAR.GZ inspector. Drop a .tar or .tar.gz file to list every entry with its size, file mode, owner, type, and modified time — parsed from the USTAR headers. Gzip is decompressed natively in-browser. Extract individual files locally. No upload. How to use: 1. Choose a tar archive: Pick or drop a .tar or .tar.gz / .tgz file. It is read locally with FileReader — nothing is uploaded. 2. Browse the entry list: The tool walks the 512-byte USTAR headers and lists each entry's path, size, Unix mode, owner, type, and modified time. 3. Extract a single file: Click Extract on any regular-file entry to download just its bytes, without unpacking the whole tarball. FAQ: Q: How does it read a tar without unpacking it? A: A tar archive is a sequence of 512-byte header blocks, each followed by the file's data padded to a 512-byte boundary. The tool reads each header to list the entry, so it can show the full contents without writing any file to disk. Q: Does it handle gzipped tarballs (.tar.gz / .tgz)? A: Yes. When the file starts with the gzip magic bytes 0x1f 0x8b it is decompressed first using the browser's native gzip DecompressionStream, then the resulting tar stream is parsed. Everything happens locally. Q: Is my archive uploaded? A: No. The .tar or .tar.gz is read with FileReader, decompressed in your browser if needed, and parsed with JavaScript. Nothing is transmitted to any server. Q: What do the mode and owner columns mean? A: The mode is the Unix permission bits in octal (for example 0755), stored in the header. Owner shows the uid/gid or the user/group names recorded in the USTAR header, which matter when the archive is restored on a Unix system. Q: What file types appear besides regular files? A: Tar marks each entry with a type flag: regular file, directory, symbolic link, hard link, character or block device, FIFO, or a long-name/PAX extension. Only regular files can be extracted to download. #### Inline Text Diff Viewer URL: https://geratools.com/text-diff-inline See exactly what changed between two pieces of text. A character-level diff highlights additions in green and deletions in red inline, using a longest-common-subsequence algorithm for minimal edits. Runs in your browser. How to use: 1. Paste the original text: Put the first, baseline version of your text into the original box. 2. Paste the changed text: Put the edited version into the changed box. The diff updates as you type. 3. Read the highlighted result: Added characters are highlighted green, removed characters are struck through in red, and a counter shows totals. FAQ: Q: What algorithm does the diff use? A: It computes the longest common subsequence (LCS) of the two strings with a dynamic-programming table, then walks that table to produce the smallest sequence of insertions and deletions. This is the same core idea behind classic diff tools. Q: Is the diff per character or per word? A: Per character. This makes it precise for short strings, code identifiers, and config values where a single transposed letter matters. For very long documents a word or line diff would be faster, but character diff shows the exact edit. Q: What do the colours mean? A: Green highlight marks characters present in the changed text but not the original (added). Red strike-through marks characters present in the original but not the changed text (removed). Unhighlighted characters are unchanged. Q: Does whitespace count? A: Yes. Spaces, tabs, and newlines are treated as ordinary characters, so an added or removed space shows up in the diff. This is intentional, since whitespace changes are a common and easy-to-miss source of bugs. Q: Is there a length limit? A: The LCS table grows with the product of the two string lengths, so very large inputs (tens of thousands of characters each) can become slow. For everyday strings, sentences, and code snippets it is effectively instant. #### Stock Ticker Suffix by Exchange URL: https://geratools.com/ticker-suffix-by-exchange Look up the Yahoo Finance ticker suffix and ISO 10383 MIC for any global stock exchange. Map exchange names to the .L, .TO, .HK and other suffixes needed by financial data APIs. How to use: 1. Search for an exchange: Type an exchange name, country, MIC code, or suffix into the search box. 2. Read the suffix: The Yahoo suffix column shows the extension to append to the bare symbol. 3. Build the full symbol: Concatenate the local ticker and the suffix, for example BP plus .L gives BP.L. FAQ: Q: What is a ticker suffix? A: A ticker suffix is a short extension such as .L or .TO that financial data providers append to a stock symbol to identify which exchange it trades on. The same company can have different suffixes on different APIs. Q: Why do US stocks have no suffix? A: Yahoo Finance treats US exchanges (NYSE, NASDAQ, AMEX) as the default, so symbols like AAPL and IBM carry no suffix. Suffixes are only needed to disambiguate non-US listings. Q: What is a MIC code? A: MIC stands for Market Identifier Code, defined by ISO 10383. It is a four-letter code such as XLON for the London Stock Exchange, used in trade reporting and many professional data feeds. Q: Does Bloomberg use the same suffixes as Yahoo? A: No. Bloomberg uses its own exchange codes such as LN for London or US for the United States, written as BP LN Equity. Yahoo uses dotted suffixes like BP.L. Always match the suffix to the specific provider. Q: Why does my Yahoo Finance API call return no data? A: The most common cause is a missing or wrong suffix. Confirm the exchange where the security is listed, then append the matching suffix from this table to the local symbol before querying. #### UN/LOCODE Port & Location Code Lookup URL: https://geratools.com/un-locode-lookup Search UN/LOCODE 5-character location codes for major ports, airports, and terminals worldwide. Look up codes like USNYC or NLRTM by code, city, or country, and see each location's function, in your browser. How to use: 1. Search a location: Type a UN/LOCODE like NLRTM, a city like Rotterdam, or a country to filter the list. 2. Confirm an exact code: Enter a full 5-character code and the tool validates its format and shows the matching location. 3. Read the function column: Each row labels whether the location serves as a port, airport, rail, or road terminal. FAQ: Q: What is a UN/LOCODE? A: UN/LOCODE is the United Nations Code for Trade and Transport Locations, a five-character code identifying ports, airports, and terminals worldwide. It combines a two-letter ISO 3166 country code with a three-character location code, so USNYC means New York in the United States and NLRTM means Rotterdam in the Netherlands. Q: How is a UN/LOCODE structured? A: The first two characters are the ISO 3166 country code and the last three identify the place, usually derived from its name. The location part uses the letters A to Z and, in rare cases, the digits 2 to 9, but never 0 or 1 to avoid confusion with the letters O and I. Q: Who maintains the list and how often does it change? A: UN/LOCODE is maintained by UNECE, the United Nations Economic Commission for Europe, and is republished about twice a year. New locations are added and obsolete ones retired, so production systems should sync against the latest official register rather than a fixed snapshot. Q: Why does this tool show only some locations? A: The full register contains more than 100,000 entries, which is too large to embed in a browser tool. This lookup curates the most-used ports and airports for quick reference; a well-formed code that is not listed may still be valid in the complete UNECE dataset. Q: What does the function column mean? A: Each UN/LOCODE carries function flags describing what the location does, such as a seaport, airport, rail terminal, or road terminal. The function column summarises those roles so you can tell at a glance whether a code refers to a port, an airport, or a multimodal hub. #### Unicode Block Browser URL: https://geratools.com/unicode-block-browser Interactive Unicode block explorer. Pick a named block to see every code point with rendered glyph, U+ notation, decimal value and HTML numeric entity, or jump to any single character by hex. How to use: 1. Look up a code point: Type a hex value such as 1F600 or U+20AC to inspect a single character and its block. 2. Pick a block: Choose a named Unicode block from the dropdown to display its code points as a glyph grid. 3. Inspect a glyph: Hover any cell to see its U+ notation and HTML entity, or read the U+ label beneath it. FAQ: Q: What is a Unicode block? A: A Unicode block is a contiguous, named range of code points reserved for a related set of characters, such as Basic Latin, Cyrillic or Emoticons. Blocks group characters by script or purpose and never overlap. Q: What does U+ notation mean? A: U+ is the standard prefix for a Unicode code point written in hexadecimal, padded to at least four digits. For example U+0041 is the letter A and U+20AC is the euro sign. Q: Why do some characters show as empty boxes? A: A glyph only renders if a font on your device covers that code point. Missing coverage shows the browser fallback box. The U+ value and entity are still correct even when no glyph appears. Q: How do I get the HTML entity for a character? A: Search for the code point and read the HTML entity row. It uses the numeric form &#decimal; which works in any HTML document regardless of named-entity support. Q: Does the browser handle characters above U+FFFF? A: Yes. Code points such as emoji live in the supplementary planes above U+FFFF and are rendered with String.fromCodePoint, which correctly produces the surrogate pair under the hood. #### Unicode General Categories URL: https://geratools.com/unicode-categories Searchable Unicode general category reference with two-letter code, full name and example characters. Look up Lu, Ll, Nd, Po and every other category, plus the regex property that matches it. How to use: 1. Search a code or name: Type a category code like Lu, a name like uppercase, or a group letter like L to filter the list. 2. Read the meaning: Each row shows the two-letter code, full name, parent group and example characters that fall into it. 3. Copy the regex property: Grab the matching Unicode property escape (such as \p{Lu}) to use it in a regular expression. FAQ: Q: What is a Unicode general category? A: Every Unicode code point is assigned exactly one general category — a two-letter code such as Lu (uppercase letter) or Nd (decimal digit). The first letter names the broad group (L letters, N numbers, P punctuation, and so on) and the second narrows it down. Q: How do I match a category in a regular expression? A: In engines that support Unicode property escapes, use \p{Code}. For example \p{Lu} matches any uppercase letter and \p{Nd} matches any decimal digit. You can also match a whole group with \p{L} for all letters. Q: What is the difference between Nd, Nl and No? A: Nd is decimal digits that combine into base-ten numbers (0–9 and their script variants). Nl is letter-like numbers such as Roman numerals. No is other numeric characters like fractions and superscripts that are not decimal digits. Q: Why do some categories like Cs and Co matter? A: Cs marks surrogate code points used by UTF-16 and Co marks private-use characters with no standard meaning. Knowing them helps you filter out code points that should not appear in normal text or that carry app-specific meaning. Q: How many general categories are there? A: There are 30 general categories grouped into seven major classes: Letter, Mark, Number, Punctuation, Symbol, Separator and Other. Every assigned and unassigned code point maps to one of them. #### Unicode Character Inspector URL: https://geratools.com/unicode-inspector Free Unicode character inspector. Paste any text and see each character broken down into its code point (U+XXXX), UTF-8 and UTF-16 encoding, Unicode block, general category and HTML/JS escapes. Runs entirely in your browser. How to use: 1. Paste your text: Type or paste any string, including emoji, accented letters or scripts like Arabic or Cyrillic. 2. Read the breakdown: Each row shows the character, its U+XXXX code point, decimal value, Unicode block, general category and escapes. 3. Copy what you need: Copy the per-character table or an individual escape sequence for use in code. FAQ: Q: Is my text uploaded? A: No. The inspector iterates over your string with the browser's own iterator and code point APIs. Nothing leaves your device. Q: Why does one emoji show as several code points? A: Many emoji are sequences: a base symbol plus skin-tone or variation selectors, or several characters joined by a zero-width joiner (U+200D). The inspector lists each code point so you can see the full sequence. Q: What is the difference between a code point and a UTF-16 code unit? A: A code point is the abstract Unicode value (up to U+10FFFF). UTF-16 stores values above U+FFFF as two 16-bit surrogate units, which is why JavaScript string length can exceed the number of visible characters. Q: What does the general category mean? A: Unicode assigns each code point a two-letter category such as Lu (uppercase letter), Nd (decimal digit), Zs (space) or Cf (format control). It tells you the broad role of the character. Q: How is the Unicode block determined? A: Each code point falls in a named range — Basic Latin, Cyrillic, Arabic, Emoji and so on. The tool maps the numeric value to its block using the standard Unicode block boundaries. #### Unicode NFKD Decomposer URL: https://geratools.com/unicode-nfkd Normalise text to Unicode NFKD (Compatibility Decomposition), the most aggressive form, folding ligatures and full-width forms while splitting precomposed characters into base plus combining marks. Browser-local. How to use: 1. Paste your text: Enter text that may contain ligatures, full-width characters, or precomposed accented letters. 2. Read the NFKD output: The tool folds compatibility variants and fully decomposes characters into base letters plus combining marks. 3. Compare code points: Examine the before and after code point lists to see the complete decomposition. FAQ: Q: What does NFKD normalisation do? A: NFKD stands for Normalization Form KD, or Compatibility Decomposition. It is the most aggressive form: it folds compatibility variants such as ligatures and full-width letters and also splits precomposed characters into a base plus combining marks, with no recomposition. Q: How is NFKD different from NFD? A: NFD only performs canonical decomposition and keeps the original characters. NFKD additionally folds compatibility variants, so the ligature fi becomes f and i and the full-width A becomes a normal A, then everything is fully decomposed. Q: Why would I choose NFKD over NFKC? A: NFKD leaves combining marks separate instead of recomposing them, which is convenient when you want to inspect or strip individual diacritics. NFKC gives the same folding but recombines marks into precomposed characters. Q: Is NFKD lossy? A: Yes, it can be. Compatibility folding discards styling like superscripts and ligature glyphs, and that cannot be undone. Use NFKD for matching, search, and analysis rather than to preserve formatted text. Q: Does my text leave the browser? A: No. The tool uses the native String.prototype.normalize function, so NFKD decomposition runs entirely in your browser and nothing is uploaded. #### Unicode Normalization Forms URL: https://geratools.com/unicode-normalization-forms Reference for Unicode normalization forms with canonical vs compatibility equivalence and programming guidance. Paste text and see live NFC, NFD, NFKC and NFKD output with length and code-point changes. How to use: 1. Paste your text: Enter or paste any string, including accented letters, ligatures or full-width characters. 2. Compare the four forms: See the NFC, NFD, NFKC and NFKD output side by side with the resulting code-point count for each. 3. Pick the right form: Use the guidance to choose NFC for storage and display, or a compatibility form for search and matching. FAQ: Q: What is the difference between NFC and NFD? A: Both preserve the exact same characters (canonical equivalence). NFD decomposes each accented letter into a base letter plus separate combining marks, while NFC composes them back into single precomposed characters where one exists. NFC is usually shorter and is the recommended form for storage and the web. Q: When should I use NFKC or NFKD? A: Use the compatibility forms (the ones with K) when you want visually or functionally similar characters to compare as equal — for example turning the ligature fi into f and i, or full-width digits into normal ones. They are ideal for search, identifiers and deduplication, but they lose formatting distinctions, so do not use them to store user-visible text. Q: Does normalization change which characters are present? A: Canonical forms (NFC, NFD) never change the meaning — they only re-arrange composition. Compatibility forms (NFKC, NFKD) can change characters, replacing ligatures, super/subscripts and width variants with plain equivalents, which is a lossy transformation. Q: Why do two identical-looking strings compare as unequal? A: They may use different normalization. The letter é can be one precomposed code point or an e followed by a combining accent. Byte-for-byte they differ, so equality and sorting fail. Normalising both strings to the same form (usually NFC) before comparing fixes it. Q: Which form should usernames and identifiers use? A: Apply NFKC to fold compatibility variants so visually identical names cannot impersonate each other, then compare. Many systems normalise identifiers to NFKC and reject mixed-script or confusable sequences on top of that. #### Unicode Script Codes URL: https://geratools.com/unicode-script-codes Searchable ISO 15924 four-letter script code reference with the numeric code, the Unicode Script property alias and example glyphs for each writing system. How to use: 1. Search by code or name: Type a four-letter code like Latn, a script name like Cyrillic, or paste a sample glyph to filter. 2. Read the alias: Each row shows the ISO 15924 code, numeric code and the Unicode Script property alias used in \p{Script=...}. 3. Use it in regex or BCP 47: Apply the code as a Unicode property value or as the script subtag in a language tag such as zh-Hant. FAQ: Q: What is an ISO 15924 script code? A: ISO 15924 assigns each writing system a four-letter code with an initial capital, like Latn for Latin or Cyrl for Cyrillic, plus a three-digit numeric code. These codes label scripts independently of language and are used in BCP 47 language tags and Unicode data. Q: How do script codes relate to Unicode property aliases? A: Unicode's Script property uses long names (Latin, Cyrillic) and short aliases that match the ISO 15924 codes (Latn, Cyrl). In a regex you can write \p{Script=Latin} or \p{Script=Latn}; both select the same set of code points. Q: What is the script subtag in a language tag? A: In BCP 47, the optional script subtag is the ISO 15924 code placed after the language, as in zh-Hant (Traditional Han) or sr-Cyrl (Serbian in Cyrillic). Include it only when it adds information the language subtag does not already imply. Q: Are Hans and Hant separate scripts? A: They are ISO 15924 variants of Han (Hani): Hans is Simplified and Hant is Traditional. Hani is the umbrella code. Use Hans or Hant in language tags to distinguish the two written forms of Chinese. Q: Does this tool store the glyphs I paste? A: No. Filtering runs entirely in your browser. Anything you type or paste stays on your device — nothing is uploaded, logged or stored. #### Video Thumbnail Extractor URL: https://geratools.com/video-thumbnail-extractor Load a video into an HTML5 video element, seek to fixed timestamps or even intervals, and capture each frame to a downloadable PNG via Canvas. Supports batch extraction. Local-only — your video is never uploaded. How to use: 1. Choose how to extract: Pick even intervals (a frame every N seconds) or a custom list of exact timestamps in seconds. 2. Load your video: Select an MP4, WebM, or MOV. It plays in a hidden video element entirely inside your browser. 3. Download frames: Each captured frame appears as a PNG thumbnail with a download link beside its timestamp. FAQ: Q: How are the frames captured? A: The video is loaded into a hidden HTML5 video element. For each timestamp the tool sets currentTime, waits for the seeked event, then draws the current frame onto a Canvas and exports it as a PNG data URL. Q: What video formats are supported? A: Any format your browser can play natively — usually MP4 (H.264), WebM, and often MOV. If the browser cannot decode the codec, the frames cannot be captured. Q: Is my video uploaded? A: No. The file is loaded via a local object URL and processed in the browser. Nothing is sent to a server, so it works offline and your video stays private. Q: At what resolution are the thumbnails saved? A: Frames are captured at the video's native resolution (videoWidth × videoHeight) and saved as full-quality PNGs; the on-page previews are just scaled down for display. Q: Is there a limit on how many frames I can extract? A: For performance the tool caps extraction at 200 frames per run. For very long videos, increase the interval or extract specific sections at a time. #### Voltage & Frequency by Country URL: https://geratools.com/voltage-frequency-by-country Reference table of mains electricity voltage (100V, 120V, 220V, 230V, 240V) and frequency (50 Hz or 60 Hz) for countries worldwide. Confirm whether your devices need a voltage converter before you travel. How to use: 1. Search a country: Type a country name to see its mains voltage and frequency. 2. Filter by voltage band: Use the selector to list only 100-127V or 220-240V countries. 3. Decide on a converter: Compare the destination voltage with your device's rating to know whether a simple adapter is enough or you need a voltage converter. FAQ: Q: What are the two main voltage standards? A: The world splits roughly into a 100-127V band (North America, Japan, parts of South America) and a 220-240V band (most of Europe, Africa, Asia, and Oceania). Plugging a 120V-only device into a 230V socket can destroy it, while a 230V device on 120V often simply underperforms or fails to start. Q: What is the difference between 50 Hz and 60 Hz? A: Frequency is how many times per second the alternating current reverses direction. Most of the world uses 50 Hz; the Americas and a few other countries use 60 Hz. Modern electronics with switching power supplies handle either, but clocks, motors, and some older appliances can run slow or fast on the wrong frequency. Q: Do I need a voltage converter? A: Only if your device is single-voltage and the destination differs. Check the label: if it reads 100-240V, it is dual-voltage and needs only a plug adapter. If it reads a single value like 120V, you need a step-up or step-down converter rated above the device's wattage to use it abroad safely. Q: Is the voltage exactly the listed value? A: No — these are nominal values. Real grid voltage varies within a tolerance, typically plus or minus 10 percent. A 230V grid may deliver anywhere from about 207V to 253V. Devices are designed to tolerate this range, so the nominal figure is what you use for compatibility checks. Q: Why does the UK list 230V when older sources say 240V? A: The UK historically ran at 240V and continental Europe at 220V. Both were harmonized to a nominal 230V with a wider tolerance band, so equipment is interchangeable. In practice UK sockets still often measure close to 240V, which is within the 230V tolerance. #### WAV Header Inspector URL: https://geratools.com/wav-header-inspector Free WAV header inspector that decodes the RIFF/WAVE header of a .wav file in your browser — showing audio format, sample rate, channel count, bit depth, byte rate, block align and exact duration. Runs locally with DataView, no upload. How to use: 1. Load a WAV file: Drop a .wav file onto the box or click to browse. Only the header bytes are read with DataView; the file stays on your device. 2. Read the decoded fields: The inspector parses the RIFF container and the fmt chunk and lists audio format, channels, sample rate, byte rate, block align and bit depth. 3. Check the computed duration: Duration is derived from the data chunk size divided by the byte rate, giving the exact playback length in seconds. FAQ: Q: What is the RIFF/WAVE format? A: WAV is a RIFF (Resource Interchange File Format) container. It begins with the ASCII tag RIFF, a 4-byte file size, then WAVE, followed by sub-chunks. The fmt chunk holds the audio parameters and the data chunk holds the raw samples. Q: How is the duration calculated? A: Duration in seconds equals the data chunk size in bytes divided by the byte rate, where byte rate is sampleRate × channels × (bitDepth / 8). For example a 44100 Hz, 16-bit stereo file has a byte rate of 176400 bytes per second. Q: What does the audio format number mean? A: The format code in the fmt chunk identifies the encoding: 1 is uncompressed PCM, 3 is IEEE float, 6 is A-law, 7 is mu-law, and 65534 is WAVE_FORMAT_EXTENSIBLE. The inspector labels the common codes for you. Q: Why might the fmt chunk not be right after WAVE? A: The WAV spec allows other chunks (like LIST or fact) before fmt or data. The inspector walks the chunk list by reading each chunk ID and size, so it finds fmt and data wherever they appear. Q: Is the audio uploaded to a server? A: No. The header is parsed entirely in your browser with the FileReader and DataView APIs. No bytes are sent anywhere, so the tool works offline and keeps your audio private. #### WebRTC ICE Candidate Types URL: https://geratools.com/webrtc-ice-candidates Reference for WebRTC ICE candidate types — host, server-reflexive, peer-reflexive and relayed — with the SDP candidate-attribute format, NAT traversal notes and a live candidate-line parser. How to use: 1. Read the candidate types: Review what host, server-reflexive, peer-reflexive and relayed candidates each represent and how they are discovered. 2. Paste a candidate line: Enter a candidate attribute string from your SDP or an RTCIceCandidate and the parser breaks out its type, address, transport and priority. 3. Plan NAT traversal: Use the traversal notes to predict which candidate ICE will select and when a TURN relay is required. FAQ: Q: What is an ICE candidate? A: An ICE candidate is one possible network address — IP, port and transport — at which a WebRTC peer might be reachable. ICE gathers several candidates per peer, pairs them and runs connectivity checks to find the best working path. Q: What is the difference between srflx and relay? A: A server-reflexive (srflx) candidate is the public address a STUN server observes for you, allowing a direct peer-to-peer path through a cone NAT. A relay candidate is an address on a TURN server that forwards media when no direct path works, at the cost of extra latency. Q: What does typ host mean in a candidate line? A: It marks a host candidate — a local interface address such as a LAN IP or, in modern browsers, an mDNS .local hostname that masks the real IP. Host candidates have the highest priority and are tried first. Q: When is a peer-reflexive candidate created? A: A prflx candidate is not signalled in advance. It is discovered during connectivity checks when a NAT maps a new port for an incoming STUN probe, revealing an address neither STUN nor TURN had reported. Q: Does this tool send my candidate anywhere? A: No. The candidate line is parsed entirely in your browser with JavaScript. Nothing is uploaded, logged or stored. #### Zero-Width Character Steganography URL: https://geratools.com/zero-width-stego Embed a secret message into invisible zero-width Unicode characters, encoding each bit as a zero-width space or zero-width joiner. Decode any zero-width-tagged text back to the hidden message. How to use: 1. Provide cover and secret: Enter the visible cover text and the secret message you want to embed inside it. 2. Encode: The tool turns the secret into bits, maps each bit to a zero-width space or zero-width joiner, and injects the invisible payload into the cover text. 3. Decode later: Paste the combined text into decode mode; the tool extracts the zero-width characters and rebuilds the hidden message. FAQ: Q: How does zero-width steganography work? A: Each character of the secret is converted to 8 bits. A bit value of 0 is stored as a zero-width space (U+200B) and a bit value of 1 as a zero-width joiner (U+200D). These characters take no visible space, so the cover text looks unchanged. Q: Why is the hidden text invisible? A: Zero-width characters are real Unicode code points designed for typographic control, but they render with no width. Embedded among normal letters they are imperceptible to a reader while still surviving copy and paste. Q: Is this encryption? A: No. It is concealment, not encryption. Anyone who knows the zero-width scheme can decode the payload, so encrypt the secret first if you need genuine confidentiality. Q: Where does the payload sit in the cover text? A: This tool appends the zero-width sequence after the first character of the cover text so it is carried inside the string. Decoding scans the whole string for zero-width characters regardless of position. Q: Will the hidden message survive everywhere? A: Often on platforms that preserve Unicode, such as chat apps, documents and many web forms. Some systems strip or normalise zero-width characters, which would erase the payload, so test your channel first. #### ZIP File Inspector URL: https://geratools.com/zip-inspector Free ZIP inspector. Drop a .zip file to list every entry with its uncompressed size, compressed size, compression ratio, method, CRC-32, and last-modified date — read from the central directory. Extract individual files locally. No upload; runs in your browser. How to use: 1. Choose a ZIP file: Pick or drop a .zip archive. It is read locally with FileReader — nothing is uploaded. 2. Browse the entry list: The tool reads the ZIP central directory and lists each file's name, sizes, ratio, method, and date. 3. Extract a single file: Click Extract on any entry to decompress just that file and download it, without unpacking the whole archive. FAQ: Q: How can it read a ZIP without extracting everything? A: A ZIP file ends with a central directory that indexes every entry: its name, compressed and uncompressed size, method, CRC, and date. The tool reads only that index, so listing is instant even for large archives. Q: Is my archive uploaded anywhere? A: No. The .zip is read with FileReader and parsed in your browser. Even single-file extraction is done locally with the browser's built-in DecompressionStream. Nothing is transmitted. Q: Which entries can it extract? A: Stored (uncompressed) and standard Deflate entries — by far the most common — extract directly using the browser's native Deflate support. Rare methods like BZIP2 or LZMA inside a ZIP cannot be expanded here. Q: What does the compression ratio mean? A: It is how much smaller the stored data is than the original: 1 minus compressed size over uncompressed size, as a percentage. Already-compressed files like JPEGs or MP4s show near 0 percent; text and code compress well. Q: Why does a folder show as a zero-byte entry? A: ZIP stores directories as separate entries whose names end in a slash and have zero length. They mark folder structure; the actual files are listed as their own full-path entries. #### Time Ago Calculator URL: https://geratools.com/time-ago-calculator Calculate how long ago a date was, or how far in the future it is, with a plain-language result plus an exact days, hours, minutes and seconds breakdown. Compare against now or any other date — all in your browser. How to use: 1. Pick the date: Choose the date and time you want to measure from using the date-time picker. 2. Choose what to compare against: Keep "Compare against now" ticked, or untick it to compare against a second date. 3. Read the result: See a plain-language "X ago" or "in X" plus an exact breakdown in days, hours, minutes and seconds. FAQ: Q: Can it count time into the future too? A: Yes. If the date is later than the comparison point, the result reads "in X" instead of "X ago", so it works as a countdown as well. Q: Can I compare two specific dates? A: Yes. Untick "Compare against now" and a second date picker appears so you can measure the gap between any two dates. Q: Is my data kept private? A: Yes. The calculation runs entirely in your browser with no network requests, so your dates are never uploaded. Q: How does it choose the plain-language unit? A: It picks the largest natural unit for the gap — seconds, minutes, hours, days, weeks, months or years — so a 90-minute gap reads "1 hour ago" rather than "90 minutes ago". Q: What is the difference between the phrase and the breakdown? A: The phrase is a single rounded unit for readability, while the breakdown is the exact remainder in days, hours, minutes and seconds. Use the breakdown when you need precision. Q: Does it use my local time zone? A: Yes. The date picker and the current-time comparison use your device's local time zone, so results match the clock you see. Q: How are months and years estimated? A: For the plain-language phrase, months and years use average lengths (about 4.35 weeks per month, 12 months per year). The day/hour/minute/second breakdown is exact. #### HAR File Viewer URL: https://geratools.com/har-file-viewer Free HAR file viewer — open a .har network capture from your browser DevTools and see every request's method, status, type, size and timing in a sortable table. HAR files can contain cookies and headers, so this tool parses everything in your browser and never uploads it. How to use: 1. Export a HAR file: In your browser's DevTools Network tab, right-click a request and choose Save all as HAR, or use the export button. 2. Open it here: Pick the .har file with the file selector. It is read locally and parsed in your browser. 3. Inspect and filter: Browse every request in a table and filter by URL to find the calls you care about. FAQ: Q: Is my HAR file uploaded anywhere? A: No. HAR files often contain cookies, auth headers and request bodies, so this viewer reads the file with the local FileReader API and parses it in your browser — nothing is sent over the network. Q: What does each column show? A: For every request you see the HTTP method, response status, content type (MIME), response size, total time in milliseconds, and the full URL. Status codes 400 and above are highlighted as errors. Q: Why is a request size shown as a dash? A: Some HAR exports record a content size of -1 when the body was not captured (for example cached or blocked responses). Those are shown as a dash and excluded from the total bytes count. Q: How do I create a HAR file? A: Open DevTools (F12) in Chrome, Edge or Firefox, go to the Network tab, reproduce the activity, then right-click any request and choose Save all as HAR with content (or use the download/export icon). Q: Can I filter the requests? A: Yes. Type into the Filter by URL box and the table shows only requests whose URL contains your text — for example api, .js, or a domain name. The request count and total size update to match the filter. Q: What is a HAR file used for? A: HAR (HTTP Archive) files are commonly shared with support teams to diagnose slow pages, failed API calls, and oversized assets. This viewer lets you inspect one yourself before sharing, since they can leak session cookies and tokens. #### Rotate PDF Pages URL: https://geratools.com/rotate-pdf Free online tool to rotate PDF pages 90, 180 or 270 degrees. Rotate every page, only the odd or even pages, or nudge individual pages from live thumbnails, then download. 100% in your browser — nothing is uploaded. How to use: 1. Open your PDF: Drop a PDF onto the tool or click to pick one. Pages render as live thumbnails so you can see exactly which way each is facing. 2. Choose a rotation: Pick 90 clockwise, 180 (flip), or 90 counter-clockwise, then apply it to every page, only the odd pages, or only the even pages. 3. Fine-tune individual pages: Click any thumbnail to nudge just that page 90 degrees clockwise. The preview rotates instantly so you can confirm before exporting. 4. Download the rotated PDF: Press Download to save a new PDF with your rotations baked in. Text stays selectable and quality is untouched. FAQ: Q: How do I rotate every page in a PDF at once? A: Load your file, choose the rotation you want (90 clockwise, 180, or 90 counter-clockwise) from the dropdown, and press "Apply to all pages". Every page is marked for rotation and you can download immediately. Q: Can I rotate only some pages and leave the rest alone? A: Yes. Click an individual thumbnail to rotate just that page, or use the "Odd pages only" and "Even pages only" buttons — perfect for double-sided scans where alternate pages came in upside down. Q: Does rotating reduce the quality of my PDF? A: No. The tool only changes each page's rotation flag in the PDF — it never re-renders, re-compresses, or rasterises the content. Text stays selectable and images keep their original resolution. Q: Is my PDF uploaded to a server? A: Never. The whole tool runs inside your browser using WebAssembly. Your file is read locally, rotated locally, and downloaded locally — nothing is sent anywhere, so it is safe for confidential documents. Q: What is the difference between 90 clockwise and 90 counter-clockwise? A: Clockwise (90 degrees) turns the top of the page to the right; counter-clockwise (270 degrees) turns the top of the page to the left. Use 180 to flip a page that scanned upside down. Watch the thumbnail preview to pick the right one. Q: My PDF already has some rotated pages — will this break them? A: No. The tool reads each page's existing rotation and adds your chosen turn on top of it, so a page that was already rotated keeps a correct final orientation rather than being reset. #### PDF Text Extractor URL: https://geratools.com/pdf-text-extractor Free in-browser PDF text extractor. Open any PDF, extract every page of text with layout preserved, then copy it or download a clean .txt file. Page ranges, page markers and hyphen re-joining supported. Nothing is uploaded — it all runs in your browser. How to use: 1. Open your PDF: Click the file picker and choose any PDF on your device. It is read locally — never uploaded. 2. Choose what to extract: Leave the page box empty for the whole document, or type a range like 1-3,5,8- to pull only the pages you want. 3. Copy or download the text: Review the extracted text, then click Copy all text to put it on your clipboard or Download .txt to save a plain-text file. FAQ: Q: How do I extract text from a PDF without uploading it? A: This tool parses the PDF entirely inside your browser using a local PDF engine. The file never leaves your device, so there is no upload, no server and no account — it works the same whether you are online or offline once the page has loaded. Q: Why is some text missing or the page comes out empty? A: A PDF only contains selectable text if it was generated from a real document. Scanned pages and photographed receipts are stored as images, so there is no text layer to pull out. The tool flags those pages as empty; turning them into text needs OCR (optical character recognition), which this extractor does not perform. Q: What does the Preserve layout option do? A: With it on, the extractor reads each glyph's position on the page, groups runs into lines by their vertical position and sorts them left-to-right and top-to-bottom. That keeps paragraphs, headings and columns roughly in reading order. Turn it off for a simpler run-on stream that follows the raw order stored in the file. Q: Can I extract text from only specific pages? A: Yes. Type a page expression such as 2, 5-9 or 10- in the Pages box. Single pages, ranges and open-ended ranges all work, and they combine with commas. Leave the box empty to extract the entire document. Q: What is the Re-join hyphens option for? A: When text wraps at the right edge of a line, PDFs often split a word with a hyphen, for example exam-ple. Enabling Re-join hyphens stitches those fragments back into a single word so the copied text reads cleanly and searches correctly. Q: Is there a size or page limit? A: There is no hard limit — the only constraint is your device's memory, because the whole PDF is processed locally. Very large documents (hundreds of pages) take a few seconds and you will see a progress bar. Using a page range keeps big files fast. #### Add Page Numbers to a PDF URL: https://geratools.com/pdf-page-numbers Free tool to add page numbers to a PDF in your browser. Choose the corner, format (1, 1/10, Page 1 of 10, roman numerals), font, size, colour, margins, start number and page range. Nothing is uploaded — it all runs locally. How to use: 1. Add your PDF: Drop a PDF onto the box or click to choose one. The tool reads the page count locally — the file never leaves your device. 2. Pick position and format: Choose a corner (such as bottom centre) and a number format like "Page {n} of {total}" or roman numerals. 3. Tune the look and range: Set the font, size, colour and margins, choose a start number, and optionally skip the cover page or limit numbering to a page range. 4. Download the numbered PDF: Click Add page numbers and download the result. Page numbers are drawn directly into the document. FAQ: Q: Does my PDF get uploaded anywhere? A: No. The file is read and rewritten entirely in your browser using pdf-lib. No page, no number and no metadata is ever sent to a server, which makes this safe for confidential contracts, court bundles and financial reports. Q: What number formats can I use? A: You can type any template using three tokens: {n} for the current page number, {total} for the count of numbered pages, and {roman} for lowercase roman numerals. Presets include "1, 2, 3", "1 / 10", "Page 1", "Page 1 of 10", "- 1 -" and "i, ii, iii". Add a fixed prefix if you want something like "Exhibit 1". Q: Can I start numbering at a page other than the first? A: Yes. Use the From page and To page fields to limit numbering to a range, and tick "Skip first page" to leave a cover unnumbered. You can also set the starting number, so a section can begin at 1 even if it is the fifth physical page. Q: Will it work on landscape or rotated pages? A: Yes. The tool reads each page's rotation and draws the number upright in the corner you chose, so pages rotated 90, 180 or 270 degrees still read correctly rather than appearing sideways. Q: Can I match my document's typeface and colour? A: You can choose Helvetica, Times or Courier, toggle bold, set any point size from 4 to 96, and pick any colour with the colour picker. The side and top/bottom margins are adjustable in PDF points so the number sits exactly where you want. Q: Is this suitable for legal Bates numbering? A: It handles the common case of sequential page numbering with a prefix and a chosen start value, which covers many Bates-style workflows. For strict legal production with zero-padded numbers and confidentiality stamps, treat it as a fast first pass and confirm against your firm's requirements. #### HTML Live Editor URL: https://geratools.com/html-live-editor A free CodePen-style HTML live editor. Edit HTML, CSS and JavaScript in three panes and watch a sandboxed preview update instantly. Autosaves your work, captures console output, exports a single .html file — all in your browser. How to use: 1. Write your markup: Type or paste HTML into the HTML pane — just the body content, no boilerplate needed. 2. Style and script it: Switch to the CSS and JS tabs to add styles and behaviour. With auto-run on, the preview refreshes as you type. 3. Save or export: Press Save snapshot to keep a named version in your browser, or Export .html to download a complete standalone page. FAQ: Q: Is this HTML editor really free and private? A: Yes. It runs entirely in your browser with no account and no upload. Your HTML, CSS and JavaScript never leave your device — they are rendered locally inside a sandboxed iframe and autosaved only to your own browser storage. Q: How does the live preview work? A: Your three panes are combined into a single document and loaded into a sandboxed iframe via the srcdoc attribute. The sandbox allows scripts and forms but isolates the preview from the page around it, so a broken script can never crash the editor. Q: Does my JavaScript actually run? A: Yes. The JS pane executes inside the preview frame exactly as it would on a real page. console.log output and any runtime errors are forwarded to the in-app console panel, which you open with the Console button. Q: Can I save my work and come back later? A: The current pen autosaves continuously to localStorage, so reopening the page restores exactly what you were editing. You can also press Save snapshot to keep up to 30 named versions and reload any of them with one click. Q: Can I import an existing HTML file? A: Yes. Use the Import button to load a .html file. The editor splits it into the three panes automatically — inline style blocks go to CSS, inline scripts go to JS, and the body markup goes to HTML. External script tags with a src attribute are dropped for safety. Q: How do I get my finished page out of the editor? A: Press Export .html to download a single self-contained file with your CSS and JS inlined into a valid HTML document. Open it in any browser or drop it straight onto a static host — no build step required. #### Data Anonymizer URL: https://geratools.com/data-anonymizer Free in-browser data anonymizer. Paste CSV or JSON, auto-detect PII columns, replace emails, names, phone numbers, credit cards and more with realistic fake values, then export. Nothing is ever uploaded. How to use: 1. Choose CSV or JSON and paste your data: Pick the CSV or JSON tab and paste a header row plus rows, or an object / array of objects. 2. Analyse and auto-detect PII: Press Analyse — the tool scans every column header and value sample and suggests a masking strategy for each field. 3. Adjust the masking plan: Override any field — keep it, redact it, hash it, or swap it for a realistic fake name, email, phone, card and more. 4. Export the anonymised result: Download the masked CSV or JSON, or copy it to your clipboard. The original data never leaves your browser. FAQ: Q: How does the data anonymizer detect personal data? A: It inspects each column header (matching names like email, phone, ssn, card, first_name) and also pattern-matches a sample of the values against email, phone, credit-card, IBAN, SSN, IP and date formats. Each field gets a suggested strategy that you can override. Q: Are the fake values realistic and consistent? A: Yes. Emails look like real emails, cards are Luhn-valid 16-digit numbers, phones and SSNs follow real formats. Each original value is hashed to seed its fake, so the same input always maps to the same output — your joins, counts and duplicates stay intact. Q: Is my data uploaded anywhere? A: No. The entire tool runs in your browser using JavaScript. Your file is parsed, masked and exported locally — there is no server, no network request and no logging of your data. Q: What masking strategies are available? A: Keep as-is, full redaction, a stable hash token, fake full / first / last names, fake email, phone, credit card, IBAN, SSN, street address, city, company, username, IP address, and date shifting by a few days. Q: Can I use the output as test or demo data? A: That is the main use. Because formats are preserved and values are internally consistent, anonymised CSV or JSON works as safe seed data for staging environments, demos, screenshots, bug reports and analytics without exposing real customers. Q: Does hashing let me re-identify people later? A: The hash token is one-way and stable but not reversible, so you cannot recover the original value from it. It is useful when you need to preserve which rows share the same value (for grouping) without revealing what that value was. #### PDF N-up: Multiple Pages Per Sheet URL: https://geratools.com/pdf-n-up Free PDF N-up tool. Print 2, 4, 6, 8, 9 or 16 pages per sheet to save paper — choose layout, sheet size, margins and cut borders, then download. Runs entirely in your browser; nothing is uploaded. How to use: 1. Load your PDF: Choose the PDF you want to print compactly. It is read in your browser and never uploaded. 2. Pick how many pages per sheet: Select a layout such as 2-up, 4-up or 9-up, then set the target sheet size and orientation. 3. Tune margins, gutter and cut borders: Adjust the outer margin and the gutter between cells, and toggle the thin border that marks where to cut. 4. Build and download: Click Build N-up PDF to download a new PDF with your pages arranged on each sheet, ready to print. FAQ: Q: What does N-up printing mean? A: N-up printing places several source pages onto a single physical sheet — 2-up means two pages per sheet, 4-up means four, and so on. It is used to save paper, create handouts and proof multi-page documents at a glance. Q: How many pages can I fit on one sheet? A: This tool supports 2-up, 4-up, 6-up, 8-up, 9-up and 16-up, in both row-first and column-first grids. Each source page is scaled to fit its cell while keeping its aspect ratio, so nothing is stretched or cropped. Q: Is my PDF uploaded anywhere? A: No. The entire imposition happens locally using the pdf-lib library running in your browser. Your file never leaves your device, which makes it safe for contracts, statements and other sensitive documents. Q: Can I choose which pages to include? A: Yes. Leave the page-range box empty to use every page, or enter a range like 1,3-5,8 to select specific pages and reorder which ones land on each sheet. Q: Why are there thin lines around each page? A: Those are optional cut-line borders that show exactly where each placed page sits on the sheet, which is handy when you plan to guillotine or fold the printout. Untick the border option if you would rather print without them. Q: What sheet sizes and orientations are supported? A: You can target A4, A3, US Letter or US Legal in portrait, landscape or an automatic orientation that matches the grid — or choose "Match source page size" to tile pages at their native dimensions. Margins and the gutter between cells are set in millimetres. #### ZIP Archive Explorer URL: https://geratools.com/zip-archive-explorer Free online ZIP explorer. Open a .zip archive, see its full folder tree with file sizes and compression ratios, preview text and images inline, and extract individual files. 100% in your browser — nothing is uploaded. How to use: 1. Open a .zip file: Drag a .zip archive onto the drop zone or click Choose .zip file. The archive is parsed locally in your browser. 2. Browse the contents: Expand folders in the tree to see every file with its uncompressed size, or type in the filter box to jump straight to a path. 3. Preview a file: Click any file. Text files and images render inline in the preview pane; binary files show their size and type. 4. Extract what you need: Click the download arrow next to any file to save just that one file — no need to unzip the whole archive. FAQ: Q: Is my ZIP file uploaded to a server? A: No. The archive is read entirely inside your browser using JavaScript. The bytes never leave your device — there is no upload, no server, and no network request involved in opening or extracting files. Q: What file types can be previewed inline? A: Common text formats (txt, md, json, js, ts, css, html, xml, yaml, csv, code files and more) render as readable text, and images (png, jpg, gif, webp, svg, bmp, ico, avif) display as pictures. Everything else is treated as binary and can still be extracted. Q: Can I extract a single file without unzipping everything? A: Yes — that is the main advantage of this tool. Click the download arrow next to any file and only that file is decompressed and saved, which is much faster than extracting a large archive just to grab one item. Q: How large a ZIP can it handle? A: It can open archives up to roughly a few hundred megabytes, limited mainly by your available browser memory. The whole archive is held in memory, so very large multi-gigabyte files may be slow or fail on low-memory devices. Q: Why is a text file shown as too large to preview? A: Inline text preview is capped at about 512 KB to keep the page responsive. Files above that limit are not rendered in the preview pane, but you can still extract them with the download button and open them in a proper editor. Q: Does it support password-protected or encrypted ZIP files? A: No. Encrypted ZIP archives cannot be read because the underlying browser library does not decrypt them. Use a desktop tool for password-protected archives; this explorer works only with standard, unencrypted ZIP files. #### PDF Booklet Imposition Tool URL: https://geratools.com/pdf-booklet-imposition Free PDF booklet maker. Reorders your pages into 2-up saddle-stitch (signature) order so you can print double-sided, fold and staple into a real booklet. Runs entirely in your browser — nothing is uploaded. How to use: 1. Upload your PDF: Choose the source PDF. It is read in your browser only — nothing is uploaded to any server. 2. Pick the spread size and binding edge: Use Auto to place two source pages side by side, or pick a fixed sheet such as A4 or US Letter. Choose left binding for English, right for Arabic or Hebrew. 3. Set signatures and duplex flip: Keep one booklet for short documents, or split into 8/16/32-page signatures for thick ones. Match the duplex flip edge to your printer (usually long edge). 4. Build and print: Click Build booklet PDF, print it double-sided, then fold down the middle and staple the spine. FAQ: Q: What is booklet imposition? A: Imposition is the rearrangement of page order so a folded, stapled sheet reads in sequence. For a saddle-stitch booklet the first sheet carries the last and first pages on its front and the second and second-to-last pages on its back. This tool computes that order for you and places two pages on each landscape sheet. Q: Why must the page count be a multiple of four? A: Each physical sheet, folded once, produces four printed sides (two on the front, two on the back). A saddle-stitch booklet is built from whole sheets, so the total must be divisible by four. The tool pads the end of each signature with blank pages automatically to reach the next multiple of four. Q: What is a signature and when should I split into several? A: A signature is a bundle of sheets folded together. A thin booklet can be a single signature, but a thick one folded as one bundle bulges badly and will not staple flat. Splitting into 8, 16 or 32-page signatures keeps each fold thin; you then stack the signatures in order and staple or bind them. Q: Which duplex flip edge should I choose? A: Most desktop printers flip on the long edge when printing double-sided, which is the default here. If your back pages come out upside down or in the wrong left/right order, switch to short edge. The tool reorders the back spread to match whichever you select. Q: Does this work for right-to-left languages? A: Yes. Set the binding edge to Right and the spine moves to the right-hand side, so the booklet opens and reads correctly for Arabic, Hebrew, Farsi and Urdu documents. Q: Is my PDF uploaded anywhere? A: No. The entire process runs in your browser using the pdf-lib library. Your file never leaves your device, which makes the tool safe for confidential or contractual documents. #### Line Height Calculator URL: https://geratools.com/line-height-calculator Free CSS line-height calculator: convert unitless, px, em, rem, and % in any direction, inspect leading and half-leading, check readability against WCAG guidance, and get a Bringhurst measure advisory — all client-side, nothing uploaded. How to use: 1. Enter your font size: Type the element font size in px. If you use rem, also set the root font size (default 16px). 2. Enter the line-height and pick a unit: Type the line-height value and choose its unit (unitless, px, em, rem or %). The tool converts it to every other unit instantly. 3. Choose a text context: Select body text, heading, or caption to get readability feedback calibrated to that context. 4. Check the readability verdict: The colour-coded badge tells you whether the ratio is too tight, comfortable, or too loose for the selected context. 5. Use the measure advisory: Enter the approximate characters-per-line for your layout and the tool recommends an ideal ratio using the Bringhurst formula. FAQ: Q: What is the formula for CSS line-height in pixels? A: A unitless line-height multiplies the element font size: line box (px) = unitless ratio x font size (px). For 16px text with line-height 1.5 the line box is 16 x 1.5 = 24px. The same logic applies to em values, which also resolve relative to the current font size. Rem values resolve relative to the root font size instead. Q: Why should I use a unitless line-height? A: CSS inherits line-height to child elements. A unitless ratio is inherited as a ratio, so each child recomputes the line box against its own font size. A px or % value is inherited as a fixed number, which can crowd larger nested text unexpectedly. The W3C and WCAG both recommend unitless line-height for this reason. Q: What line-height does WCAG recommend? A: WCAG 2.1 Success Criterion 1.4.12 (Text Spacing) requires that users can apply a line-height of at least 1.5 times the font size without loss of content or functionality. WCAG 1.4.8 (Visual Presentation) further recommends line spacing of at least 1.5 within paragraphs for Level AAA conformance. Q: What is leading and half-leading? A: Leading (from the metal-type era when lead strips were inserted between lines) is the extra vertical space added above the cap-height of the type. In CSS, the browser splits the leading equally above and below each line box, a concept called half-leading. This calculator approximates cap-height as 72% of the font size for Latin typefaces. Q: What is the Bringhurst measure advisory? A: Robert Bringhurst's classic rule in The Elements of Typographic Style states that wider columns need more leading because the eye has further to travel back to the start of the next line. The advisory here uses a base ratio of 1.45 and adds 0.003 per character above 65 chars/line, clamped between 1.1 and 2.0. Q: What is the difference between line-height 1.5 and 150%? A: They produce the same computed value for the current element (both equal 1.5 x font-size), but they inherit differently. A percentage is resolved to a px value on the element and that px value is inherited by children. A unitless 1.5 is inherited as 1.5 and each child recomputes against its own font size. Prefer unitless. ## Text & Writing Tools > Text tools for writers, students and social media — case converters, font and Unicode generators, counters, cleaners, ciphers and encoders. All processing happens in your browser; your text is never uploaded. ### Case & Formatting #### aLtErNaTe CaSe Converter URL: https://geratools.com/alternate-case Convert text to alternating case, flipping between uppercase and lowercase on every letter to create the mocking SpongeBob effect. Choose whether to start lowercase or uppercase; spaces and punctuation pass through unchanged. How to use: 1. Choose the first letter: Pick whether the alternation starts on a lowercase or an uppercase letter. 2. Paste your text: Type or paste the text you want to mock-case into the input box. 3. Copy the result: Press Copy to put the alternating-case text on your clipboard, ready to paste into a chat or post. FAQ: Q: What is alternating case? A: Alternating case flips between lowercase and uppercase on each successive letter, producing text like tHiS. It became popular as the mocking SpongeBob meme, used online to convey sarcasm or to mock a quoted statement. Q: Do spaces and punctuation affect the pattern? A: No. Only letters are toggled and counted. Spaces, digits, and punctuation pass through unchanged and do not advance the upper or lower toggle, so the alternation stays consistent across words. Q: Can I start with an uppercase letter? A: Yes. The First letter option lets you choose whether the very first letter is lowercase (aLtErNaTe) or uppercase (AlTeRnAtE). The rest of the text alternates from there. Q: What is it used for? A: It is mostly used humorously online to indicate a mocking or sarcastic tone, especially when quoting someone. It has no formal writing use and should be avoided in professional or accessible content. Q: Is my text sent to a server? A: No. The conversion runs entirely in your browser. Nothing you type is uploaded or stored. #### Case Study Headline Generator URL: https://geratools.com/random-case-study-headline-generator Generate case study headline formats following the problem-solution-result pattern for B2B, B2C, and enterprise success stories. Fill in your customer, metric, and timeframe to produce results-focused titles that earn clicks. How to use: 1. Pick the segment: Choose B2B, B2C, or enterprise to match the customer story you are writing. 2. Add your specifics: Enter the customer name, the metric, the result, and the timeframe so the headline reads concretely. 3. Generate and copy: Click Generate to assemble a results-focused headline, then copy it and reroll until one fits. FAQ: Q: What makes a strong case study headline? A: The strongest case study headlines lead with a concrete, quantified result and name the customer or segment. A number such as a percentage lift or a dollar figure gives instant credibility and answers the reader's main question, which is whether the outcome could apply to them. Q: Should I put the metric in the headline? A: Yes, whenever you have a clean number. A specific metric like a 3x increase or a 40 percent cost reduction is far more persuasive than a vague claim of improvement. If the number is messy or confidential, lead with the transformation instead. Q: Are these headlines ready to publish? A: They are templates with prompts for your real data. You must insert accurate figures you can substantiate and confirm the customer has approved being named. Never publish a number you cannot back up with the customer's data. Q: How long should a case study headline be? A: Aim for a single line, roughly six to twelve words, that fits in a list view and a search result. A short headline carrying one strong result outperforms a long sentence that buries the outcome. Save the detail for the subheading. Q: Does this tool send my data anywhere? A: No. All headline patterns and assembly logic are bundled into the page, so each headline is built in your browser. Nothing you enter is uploaded. #### SRT Subtitle Cleaner URL: https://geratools.com/srt-cleaner Free SRT cleaner. Strips italic, bold and font tags, removes SDH brackets like [music], speaker labels and ad or credit lines such as 'Subtitles by …', then renumbers cues. Pure JavaScript, no upload. How to use: 1. Load or paste your SRT file: Drop in an .srt file or paste the text directly into the input box. 2. Choose what to remove: Toggle the rules for HTML tags, SDH annotations, speaker labels and ad or credit lines to suit the file. 3. Copy or download the cleaned file: Cues that become empty are dropped, the rest are renumbered, and you can copy or download the cleaned .srt. FAQ: Q: What is SDH and why remove it? A: SDH stands for Subtitles for the Deaf and Hard of hearing. It adds non-dialogue cues such as [dramatic music] or (door creaks) and speaker labels. Removing them leaves only spoken dialogue, which some viewers and downstream tools prefer. Q: Which HTML and style tags are stripped? A: The cleaner removes paired and self-closing tags like , , and , as well as ASS-style override blocks in curly braces. Only the visible text remains, so a line like Hello becomes Hello. Q: How does ad and credit removal work? A: Lines matching common patterns are dropped, including 'Subtitles by …', 'Synced by …', release-group names, and any line containing a web address. This clears the injected promo cues that many downloaded subtitles carry at the start or end. Q: What happens to a cue that becomes empty? A: If cleaning removes everything from a cue — for example a cue that was only an [MUSIC] annotation — that cue is dropped entirely. The remaining cues are then renumbered from 1 so the file stays valid. Q: Is my subtitle file uploaded anywhere? A: No. Every rule runs in your browser using JavaScript. Nothing is sent to a server, so your subtitle files stay private on your own device. #### Subtitle FPS Converter URL: https://geratools.com/subtitle-fps-converter Free subtitle FPS converter. Rescales every cue timestamp by the source-to-target frame-rate ratio to resync SRT or VTT subtitles after a video was converted between frame rates. Runs entirely in your browser. How to use: 1. Load or paste your subtitles: Drop in an SRT or VTT file, or paste the text. The format is detected automatically. 2. Set the source and target frame rates: Enter the fps the subtitle was made for and the fps your video actually runs at, picking from common values such as 23.976, 24 and 25. 3. Copy or download the reframed file: Every timestamp is rescaled by the fps ratio. Preview the result and download a resynced subtitle file. FAQ: Q: Why do subtitles drift after a frame-rate conversion? A: When a film is converted from, say, 25 fps to 23.976 fps, its real-time duration changes, but subtitle timestamps made for the original speed are not. The result is a small error that grows steadily: captions start almost right, then slip further out of sync as the video plays. Q: How is the scale factor calculated? A: The factor is source fps divided by target fps. A subtitle authored for 23.976 fps played over a 25 fps video must be sped up by 23.976 ÷ 25 ≈ 0.959, so every timestamp is multiplied by that ratio. Reversing the source and target reverses the correction. Q: Which frame rates are common? A: 23.976 and 24 fps are typical for film and streaming, 25 fps is PAL television, and 29.97, 30, 50, 59.94 and 60 fps appear in NTSC and high-frame-rate video. The classic mismatch is the 23.976-versus-25 PAL/NTSC pair. Q: When should I use offset instead of FPS conversion? A: Use a constant offset when the whole file is late or early by a fixed amount and never drifts. Use FPS conversion when captions are roughly right at the start but slip progressively, which is the signature of a frame-rate mismatch rather than a simple delay. Q: Are my subtitle files uploaded? A: No. Parsing, rescaling and reformatting all happen in your browser using JavaScript. Nothing is sent to a server, so your subtitle files stay private. #### Subtitle Time Shifter / Resync URL: https://geratools.com/subtitle-time-shifter Free subtitle resync tool. Apply a constant millisecond offset or a two-point linear sync to SRT, VTT or ASS files to fix captions that are ahead, behind, or drifting. Runs entirely in your browser. How to use: 1. Load or paste your subtitles: Drop in an SRT, VTT or ASS file, or paste the text. The format is auto-detected so timestamps are rewritten in the right style. 2. Choose offset or linear mode: Use a constant offset for a uniform delay, or two-point linear sync when the drift grows over time. 3. Copy or download the resynced file: Preview the shifted output and download a corrected subtitle file in the same format you started with. FAQ: Q: When should I use a constant offset versus linear sync? A: Use a constant offset when every caption is off by the same amount — for example the whole file is half a second late. Use two-point linear sync when the captions start almost right but drift further out as the video plays, which usually means a frame-rate mismatch. Q: How does two-point linear sync work? A: You give two anchor points: a time where you know what the caption should say versus when it currently appears, near the start and near the end. The tool fits a straight line through both points and applies that scale and offset to every timestamp, correcting both the initial delay and the gradual drift at once. Q: Which formats are supported? A: SubRip (.srt), WebVTT (.vtt) and Advanced SubStation Alpha (.ass). The tool detects the format and rewrites timestamps using the correct separator and precision — milliseconds for SRT and VTT, centiseconds for ASS. Q: Can the offset be negative? A: Yes. A negative offset pulls captions earlier, which is what you want when subtitles lag behind the audio. A positive offset pushes them later. Any caption that would land before zero is clamped to the start of the file. Q: Are my files uploaded? A: No. Detection, parsing and timestamp rewriting all happen in your browser with JavaScript. Nothing is sent to a server, so your subtitle files stay completely private. #### Capitalize Each Word URL: https://geratools.com/capitalize-each-word Free tool to capitalize the first letter of every word in your text. Unlike title case, minor words are capitalized too. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your text: Type or paste the text you want to capitalize. 2. Read the capitalized result: Every word now starts with a capital letter, with the rest lowercase. 3. Copy the result: Click Copy result to send the capitalized text to your clipboard. FAQ: Q: How is this different from title case? A: This capitalizes the first letter of every word, including minor words. Title case keeps small words like a, the and of lowercase. Q: Does it handle hyphens and apostrophes? A: Yes. Each part of a hyphenated word is capitalized, and the tool keeps apostrophes intact within words. Q: Does it lowercase the rest of each word? A: Yes. It forces the first letter of every word to uppercase and the remaining letters to lowercase, so 'hELLo WORLD' becomes 'Hello World' with consistent capitalization. Q: Will it handle accented letters? A: Yes. The tool recognises accented Latin characters (such as é, ñ and ü), so words like 'café' or 'jalapeño' are capitalized correctly. Q: Is my text private? A: Yes — all processing happens in your browser and nothing is uploaded. #### Text Column Formatter URL: https://geratools.com/text-column-formatter Free text column formatter — turn delimited rows into neatly aligned monospace columns with configurable delimiter, alignment, and gap. Runs entirely in your browser, nothing is uploaded. How to use: 1. Set the delimiter: Tell the tool how your fields are separated — a pipe, comma, semicolon, or tab. 2. Paste your rows: Enter one row per line; each field is trimmed automatically. 3. Copy the aligned output: Choose left or right alignment and a column gap, then copy the monospace result. FAQ: Q: How do I use a tab as the delimiter? A: Type the two characters backslash-t in the delimiter box. The tool treats that as a real tab character when splitting your rows. Q: Why does the output need a monospace font? A: Column alignment is done by padding fields with spaces, which only lines up visually when every character has the same width. The output box uses a monospace font for that reason. Q: Is my data uploaded anywhere? A: No. The formatting runs locally in your browser and your text never leaves your device. Q: What is the difference between left and right alignment? A: Left alignment pads spaces after each value so text starts flush left; right alignment pads before each value so numbers line up by their last digit, which is best for figures and currency. Q: How is each column's width decided? A: The tool scans every row and sets each column's width to the longest value in that column, then pads shorter values to match. Trailing whitespace on the last column is trimmed. Q: What if some rows have more fields than others? A: It uses the maximum field count found across all rows. Rows with fewer fields are treated as having empty trailing cells, so the columns still line up. Q: Does it work for code comments or README tables? A: Yes. It is ideal for tidying ASCII tables in README files, aligning trailing code comments, or cleaning up terminal output before pasting it elsewhere. #### CSV Column Extractor URL: https://geratools.com/csv-column-extractor Free CSV column extractor — pick the columns you need from a CSV and get them back as tab-separated values. Handles quoted fields and embedded commas. Runs entirely in your browser, nothing is uploaded. How to use: 1. Paste your CSV: Drop in the CSV text and set the delimiter if it is not a comma. 2. Choose columns: Tick the columns you want; header names are used as labels when the first row is a header. 3. Copy the result: The selected columns are returned tab-separated, ready to paste into a spreadsheet. FAQ: Q: Does it handle commas inside quoted fields? A: Yes. The parser follows the RFC 4180 rules, so quoted fields can contain commas, line breaks, and escaped double quotes without breaking the column boundaries. Q: What if I do not tick any columns? A: When no columns are selected, the tool returns every column, so you can use it simply to convert a CSV into clean tab-separated values. Q: Can I use a delimiter other than a comma? A: Yes. You can switch the delimiter to a semicolon or tab to parse files exported with those separators, common in regions where the comma is a decimal mark. Q: Why is the output tab-separated? A: Tab-separated values paste cleanly into spreadsheets like Excel and Google Sheets, each value landing in its own cell without the quoting complications of re-emitting CSV. Q: Is my CSV uploaded anywhere? A: No. Parsing and extraction happen entirely in your browser; your data never leaves your device. #### Subtitle Converter (SRT, VTT, SBV) URL: https://geratools.com/subtitle-converter Free subtitle converter for SRT, WebVTT and YouTube SBV. Convert formats, shift timing, rescale framerate, strip tags and fix overlaps, then copy or download. 100% client-side — your files never leave your device. How to use: 1. Paste or load your subtitle file: Drop in an SRT, VTT or SBV file, or paste the text directly. The tool auto-detects the format. 2. Pick the output format: Choose SubRip (.srt), WebVTT (.vtt) or YouTube (.sbv) as your target format. 3. Shift the timing if needed: Type a positive or negative offset in seconds, or use the quick nudge buttons, to bring captions back into sync. 4. Copy or download the result: Copy the converted text to your clipboard or download it as a ready-to-use subtitle file. FAQ: Q: Which subtitle formats does this converter support? A: It reads and writes three of the most common caption formats: SubRip (.srt), WebVTT (.vtt, used by HTML5 video and most web players) and SBV (.sbv, the format YouTube exports). You can convert freely in any direction between them — SRT to VTT, VTT to SRT, SRT to SBV, and so on. Q: How do I fix subtitles that are out of sync? A: Use the time-shift control. If captions appear too early, enter a positive offset in seconds to push them later; if they lag behind the audio, enter a negative offset to pull them earlier. The quick nudge buttons let you fine-tune in 0.1-second and 1-second steps while watching the preview table update live. Q: What does the framerate / speed scale option do? A: Subtitles authored against a 25 fps source will drift when played over a 23.976 or 24 fps version of the same video (and vice versa). The framerate scale multiplies every timestamp by the correct ratio so the captions stay aligned for the whole runtime instead of slipping further out as the video plays. Q: Are my subtitle files uploaded anywhere? A: No. Every step — parsing, time-shifting, format conversion and download — happens entirely inside your browser using JavaScript. Nothing is sent to a server, so even confidential or unreleased transcripts stay completely private on your own device. Q: What is the difference between SRT and WebVTT? A: They are nearly identical: both list numbered cues with a start and end time and the caption text. The key differences are that WebVTT files begin with a WEBVTT header, use a dot before the milliseconds (00:00:01.000) instead of a comma (00:00:01,000), and support extra styling and positioning cues. This tool handles the header and punctuation differences automatically. Q: Can it clean up messy subtitles? A: Yes. Tick Strip formatting tags to remove italic, bold and colour markup along with ASS-style override blocks, leaving plain text. Tick Fix overlapping cues to automatically trim any caption whose end time runs past the start of the next one, which prevents two lines showing at once. ### Fancy Fonts & Social #### Bold Italic Unicode Text URL: https://geratools.com/bold-italic-unicode Free bold italic Unicode text generator. Convert words into Mathematical Bold Italic block letters for striking bios, headings and posts that keep their style in plain text. How to use: 1. Enter your text: Type the words you want converted into the input box. 2. See the bold italic output: Each letter is replaced live with its Mathematical Bold Italic counterpart, and digits become bold for a matching weight. 3. Copy the result: Press Copy and paste the styled text into any app that supports Unicode characters. FAQ: Q: Why do the numbers look bold but not slanted? A: The Bold Italic block defines no digits, so the tool borrows the Mathematical Bold numerals instead. They share the heavy weight even though they are upright, keeping the overall look consistent. Q: Does this work in social media bios? A: Yes. Because each character is a real Unicode code point, the bold-italic styling stays intact when pasted into Instagram, X, TikTok or Discord profiles that normally strip formatting. Q: Are any letters missing or substituted? A: No. Unlike the plain italic and script blocks, the Mathematical Bold Italic block is complete for A-Z and a-z, so every Latin letter has a direct, contiguous mapping. Q: Why does it show as squares on some devices? A: Display depends on the installed font, not on the tool. Older operating systems may lack the glyphs and show a fallback box, while modern phones and browsers render them correctly. #### Bold Serif Unicode Text URL: https://geratools.com/bold-serif-unicode Convert plain text into bold serif Unicode characters from the Mathematical Bold block (U+1D400+). Real characters — not CSS bold — so the styling survives copy-paste into bios, posts, and usernames. Free, keyless, instant. How to use: 1. Type your text: Enter the letters and digits you want to embolden. Uppercase, lowercase, and 0–9 are all supported. 2. See the bold version: Each character maps to its Unicode Mathematical Bold serif glyph, rendered instantly in the preview. 3. Copy and paste: Click Copy and drop the bold text into a profile bio, tweet, heading, or anywhere plain styling is not allowed. FAQ: Q: Is this CSS bold or real characters? A: These are real Unicode characters from the Mathematical Bold block, not formatting. Because they are distinct code points, the bold look is preserved when copied into apps that only accept plain text. Q: Which characters can it convert? A: Uppercase A–Z map from U+1D400, lowercase a–z from U+1D41A, and digits 0–9 from U+1D7CE. Spaces and punctuation are left unchanged because the block does not define bold forms for them. Q: Where is this useful? A: Anywhere you cannot apply real formatting — Instagram and Twitter bios, LinkedIn headlines, Discord names, and YouTube titles — but want certain words to stand out in bold. Q: Will it look right on every device? A: Most modern fonts include the Mathematical Bold glyphs, so it renders on the web, mobile, and chat apps. A few older fonts lack them and show boxes instead. Q: Should I use it for body text? A: No. Screen readers may announce these as math symbols, and search engines treat them differently from normal letters, so reserve them for short accents rather than full sentences. #### Mirror / Reverse Text URL: https://geratools.com/mirror-text Free mirror and reverse text tool. Flip the order of any string character by character (Unicode-safe), or render it as a true mirror image using horizontally flipped Unicode lookalike glyphs. Runs entirely in your browser. How to use: 1. Choose a mode: Pick Reverse to flip only the character order, or Mirror to also swap each letter for a horizontally flipped Unicode glyph. 2. Type or paste your text: Enter any text in the input box. The result updates live as you type, with full Unicode support for emoji and accents. 3. Copy the result: Click Copy to put the reversed or mirrored string on your clipboard, ready to paste into chats, bios, or art. FAQ: Q: What is the difference between reverse and mirror mode? A: Reverse mode only flips the order of characters, so "Gera" becomes "areG". Mirror mode also replaces each character with a horizontally flipped Unicode lookalike where one exists, so the text reads like a true reflection in a mirror. Q: Does it handle emoji and accented letters correctly? A: Yes. The tool splits the string by Unicode code points rather than UTF-16 units, so multi-byte characters such as emoji and accented letters are reversed as whole symbols instead of being broken apart. Q: Why do some characters look unchanged in mirror mode? A: Not every glyph has a horizontally flipped Unicode counterpart. Symmetric letters like A, H, I, M, O and T already look the same mirrored, and characters without a known flipped form are left as-is so the output stays readable. Q: Is my text sent to a server? A: No. All reversing and mirroring happens locally in your browser with JavaScript. Nothing you type is uploaded, logged, or stored, so it is safe for private notes. Q: Can I use mirrored text in social media bios? A: Yes. The output is plain Unicode text, so you can paste it anywhere that accepts Unicode — Instagram, X, Discord, and most chat apps. Some platforms may normalise unusual glyphs, so preview before posting. #### Monospace Unicode Text URL: https://geratools.com/monospace-unicode Free monospace Unicode text generator. Convert words and numbers into Mathematical Monospace block characters for code-style bios, posts and headings in plain-text fields. How to use: 1. Enter your text: Type the words and numbers you want converted into the input box. 2. See the monospace output: Every letter and digit is replaced live with its Mathematical Monospace equivalent. 3. Copy and paste: Press Copy and paste the typewriter-style text into any Unicode-friendly app. FAQ: Q: Will the characters line up in columns? A: Each monospace code point is metrically equal-width within fonts that support the block, so they read like a typewriter even where the surrounding app uses a proportional font. Q: Are digits included? A: Yes. The Mathematical Monospace block defines all 52 Latin letters and the digits 0-9, so letters and numbers all convert with a consistent fixed-width look. Q: Can I use this for code snippets in chat? A: It gives a code-like appearance, but it is styled display text, not real code. Anyone copying it gets the styled characters, not plain ASCII, so use proper code blocks when the code must run. Q: Why do some apps show empty boxes? A: That happens when the device font lacks these glyphs. Most modern systems render them, but older or restricted environments may substitute a fallback box. #### Cursive/Script Unicode Text URL: https://geratools.com/script-unicode Free cursive script Unicode text generator. Convert words into Mathematical Script block letters for handwritten-style bios, names and posts that keep their look in plain text. How to use: 1. Type your text: Enter the words you want styled into the input box. 2. See the cursive output: Each letter is replaced live with its Mathematical Script form, filling the math-block gaps from Letterlike Symbols. 3. Copy and paste: Press Copy and paste the handwritten-style text into any Unicode-friendly app. FAQ: Q: Why are some script letters slightly different in style? A: Eleven letters such as B, E, F, H, I, L, M, R, e, g and o were already in the Letterlike Symbols block, so their Mathematical Script code points are unassigned. The tool substitutes the existing symbols, which may look a touch different in some fonts. Q: Do numbers convert to script? A: No. The Mathematical Script block defines no styled digits, so the tool leaves 0-9 as ordinary characters to keep the output valid. Q: Is this the same as a handwriting font? A: It produces a calligraphic look, but each glyph is a distinct Unicode character rather than a font. That is why the style survives copy-paste into bios and chat fields that strip formatting. Q: Why do some characters appear as boxes? A: Some script glyphs require a fairly complete font. On modern devices most render fine, but older or limited systems may show a fallback box for the rarer letters. #### Vietnamese Precomposed vs Decomposed Unicode Normalizer URL: https://geratools.com/vietnamese-transliteration-check Detect whether Vietnamese text is encoded as NFC precomposed or NFD decomposed Unicode, then convert between them to fix floating-accent display bugs and inconsistent search. Shows code-point counts for each form. Runs in your browser. How to use: 1. Paste the text: Paste Vietnamese text you suspect is encoded oddly, for example with accents that float over letters. 2. Check the detected form: The tool reports whether the input is NFC, NFD, mixed, or plain ASCII, and counts code points each way. 3. Convert and copy: Copy the NFC version for normal storage and display, or the NFD version if a system specifically requires decomposed text. FAQ: Q: What is the difference between NFC and NFD? A: NFC stores each accented Vietnamese letter as a single precomposed code point, while NFD stores a base letter followed by separate combining accent marks. Both display the same when rendered correctly, but they are different byte sequences that compare and search differently. Q: Why does my Vietnamese text show floating accents? A: That usually means the text is in NFD decomposed form and the font or renderer is not stacking the combining marks properly. Converting to NFC merges each letter and accent into one code point, which almost always fixes the display. Q: Why do the code-point counts differ between forms? A: In NFD each accented letter expands into two or three code points, so the total is higher than NFC even though the visible text is identical. Comparing the counts is a quick way to tell which form you have. Q: Which form should I store data in? A: NFC is the safest default for databases, filenames, and web pages, because most software and search engines expect precomposed text. Use NFD only when a specific system, such as some macOS file APIs, requires decomposed form. Q: Is my text sent to a server? A: No. Detection and conversion use your browser's built-in Unicode normalization locally. Nothing you paste is uploaded, so it is safe for private content. #### Zalgo Text Generator URL: https://geratools.com/zalgo-text Free Zalgo text generator — stack random Unicode combining marks above, below and through your text for a glitchy, creepy corrupted effect. Adjustable intensity, all in your browser. How to use: 1. Enter your text: Type or paste the words you want to corrupt with Zalgo marks. 2. Set the intensity: Choose how many combining marks to stack above, below and through each character. 3. Copy the cursed text: Click Copy to grab the glitched result for social posts, usernames or messages. FAQ: Q: What is Zalgo text? A: Zalgo text is normal text overloaded with Unicode combining diacritical marks. These marks stack vertically on each character, creating a corrupted, glitchy, creepy appearance often associated with the He Comes meme. Q: How does the glitch effect work? A: Each base character is followed by randomly chosen combining marks from the Unicode ranges for marks above, below and overlay. Because these are zero-width, they pile onto the preceding character instead of taking their own space. Q: Will Zalgo text work everywhere? A: Most modern apps render the stacked marks, but some platforms clamp or strip excessive diacritics for safety, so very high intensity may display shorter or be filtered. Lower intensity is more portable. Q: Can I control how messed up it looks? A: Yes. The intensity slider sets the maximum number of marks added per character and the up, mid and down toggles control where the marks appear, from a light corruption to full chaos. Q: Is my text sent to a server? A: No. The generator runs entirely in your browser using JavaScript, so nothing you type is uploaded. #### Fancy Unicode Text Generator URL: https://geratools.com/fancy-unicode-text Free fancy text generator that converts plain text into bold, italic, script, fraktur, double-struck, monospace and circled Unicode styles. Copy-paste ready and runs entirely in your browser. How to use: 1. Type your text: Enter or paste the text you want to restyle into the input box. 2. Browse the styles: Each Unicode style — bold, italic, script and more — is shown live below. 3. Copy a style: Click Copy next to the style you like and paste it anywhere. FAQ: Q: Are these real fonts? A: No — they are Unicode characters that look like styled letters (such as the mathematical alphanumeric symbols). Because they are real characters, they paste into bios, posts and usernames where custom fonts are not allowed. Q: Why do some letters not change in certain styles? A: Some Unicode style ranges only cover letters and not digits, so numbers may stay plain in italic, script or fraktur styles. Bold, double-struck, monospace, sans and full-width include digits. Q: Is anything uploaded? A: No — the conversion runs entirely in your browser and nothing is sent to a server. Q: Will fancy text work on Instagram, TikTok and Discord? A: Usually yes, because the output is standard Unicode rather than a custom font. Most platforms that accept Unicode in bios and posts will display it. A few apps that strip non-standard characters, or screen readers, may show plain letters instead. Q: Is fancy Unicode text accessible to screen readers? A: Often not well. Styled mathematical letters may be read out character by character or skipped, so avoid using it for important or body content and keep it to decorative accents like a username or headline. Q: Can I convert it back to plain text? A: Each styled character maps from a normal letter, so deleting and retyping in a plain field restores normal text. The generator itself only converts in one direction — plain in, styled out. #### Leetspeak Converter URL: https://geratools.com/leetspeak-converter Free leetspeak (1337) converter that turns text into leet and decodes it back. Choose basic or advanced symbol-heavy substitutions. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a direction: Pick "Text → Leet" to encode or "Leet → Text" to decode. 2. Pick a level: When encoding, choose basic substitutions or advanced symbol-heavy leet. 3. Copy the result: The output updates instantly — press Copy to grab it. FAQ: Q: What is the difference between basic and advanced leet? A: Basic uses common number swaps like a to 4, e to 3 and o to 0. Advanced adds symbol-heavy swaps such as s to dollar sign and i to an exclamation mark for a denser look. Q: Why does decoding not always match the original? A: Leetspeak has no single standard and many letters map to the same symbol, so decoding is a best-effort guess that picks the most common source letter. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser and nothing is sent or stored. Q: What is leetspeak? A: Leetspeak (written 1337 or l33t) is an internet-culture writing style that replaces letters with visually similar numbers and symbols, for example writing "elite" as "31!73". It started in early bulletin-board and gaming communities. Q: What letters does basic leet replace? A: Basic mode swaps six letters: a to 4, e to 3, i to 1, o to 0, t to 7 and s to 5. Every other character is left unchanged, so the text stays easy to read. Q: What extra swaps does advanced leet add? A: Advanced mode adds b to 8, g to 9, l to 1, z to 2 and uses symbols i to ! and s to $ for a denser look, on top of a to 4, e to 3, o to 0 and t to 7. Q: Is leetspeak secure or a form of encryption? A: No. It is a stylistic substitution, not encryption — anyone can read it back. Do not use it to hide passwords or sensitive data. #### Unicode Character Inspector URL: https://geratools.com/unicode-character-inspector Free Unicode character inspector — break any text into its characters and see the code point, hex value, decimal, and category for each. Runs entirely in your browser, nothing is uploaded. How to use: 1. Paste your text: Enter any text — emoji, accented letters, and symbols are all supported. 2. Read the table: Each character is listed with its U+ code point, decimal value, and Unicode category. 3. Check the counts: The summary shows code points versus UTF-16 units, which differ for emoji and other astral characters. FAQ: Q: Why are code points and UTF-16 units different? A: Characters above U+FFFF, such as most emoji, are stored as two UTF-16 units (a surrogate pair) but count as one Unicode code point. The summary shows both so you can see where strings will behave unexpectedly. Q: How are invisible characters shown? A: Spaces, tabs, line feeds, and carriage returns get a visible label, and control characters are shown with a placeholder glyph, so you can spot hidden characters that cause bugs. Q: Is my text uploaded anywhere? A: No. The inspection runs entirely in your browser and your text never leaves your device. Q: What is a Unicode code point? A: A code point is the numeric identity of a character in the Unicode standard, written as U+ followed by hexadecimal — for example the letter A is U+0041 and 😀 is U+1F600. The inspector iterates your text by code point, so it correctly counts emoji and other characters above U+FFFF as one. Q: Why does the emoji count as one code point but two characters? A: JavaScript stores strings in UTF-16, where any character above U+FFFF (most emoji) needs two 16-bit units called a surrogate pair. Iterating by code point counts it once, but the raw string length counts it twice — which is exactly the mismatch the summary highlights. Q: How do I find a hidden or invisible character? A: Paste the text and look down the table for characters you did not expect — a non-breaking space (U+00A0), a zero-width space (U+200B), or a control character shown as a placeholder glyph. Each appears as its own row with a code point so you can locate and remove it. Q: How are character categories determined? A: The tool uses Unicode property escapes — \\p{L} for letters, \\p{N} for numbers, \\p{P} for punctuation, \\p{S} for symbols, \\p{M} for marks and \\p{Z} for separators — plus special handling for spaces, tabs and control characters. Q: What is the difference between a code point and a grapheme? A: A code point is one Unicode scalar value, while a grapheme is what a reader perceives as a single character — which may be several code points (for example a base letter plus a combining accent, or an emoji with a skin-tone modifier). This tool lists individual code points. #### Small Caps Generator URL: https://geratools.com/small-caps-generator Free small caps generator. Turn lowercase text into genuine Unicode small capitals for bios, headers and posts, with title-case, letter-spaced and bracketed variants plus a reverse decoder. Runs entirely in your browser. How to use: 1. Type or paste your text: Enter any lowercase or mixed-case text in the input box and the small caps version appears instantly below. 2. Pick a case and a style variant: Choose all small caps, title case with big first letters, or preserve your typed case, then pick a plain, letter-spaced or bracketed variant. 3. Copy and paste anywhere: Use the per-variant copy buttons to grab the exact look you want, then paste it into a bio, username, caption or document. FAQ: Q: What are Unicode small caps? A: Small caps are real Unicode characters that look like miniature capital letters, such as the small capital A at code point U+1D00. Because they are ordinary text characters and not a font, the result keeps its appearance when you copy and paste it into apps that do not let you change fonts, like social media bios and usernames. Q: Will small caps work everywhere I paste them? A: They work in most modern apps and browsers because the glyphs are standard Unicode. A few older systems or very limited fonts may show a fallback box for some letters, and screen readers may read them inconsistently, so use them for decoration rather than essential information. Q: Why does the letter x stay lowercase? A: Unicode never defined a dedicated small-capital X. To keep the text reversible and avoid an odd-looking substitute, the tool leaves x as a normal lowercase x. Every other letter from a to z has a true small-capital glyph. Q: Can I turn small caps back into normal text? A: Yes. Switch to the small caps to text mode and paste your small caps in. The decoder maps each small-capital glyph back to its plain lowercase letter, and any spaces, digits or punctuation pass through untouched. Q: Do small caps help my SEO or accessibility? A: No. Search engines and assistive technology treat these as decorative symbols, so avoid them in headings, links and body copy that needs to be read or indexed. They are best reserved for short stylistic touches. Q: Is my text private? A: Completely. Every conversion happens locally in your browser using built-in character maps. Nothing you type is uploaded, logged or stored anywhere. #### Unicode Character Explorer URL: https://geratools.com/unicode-character-explorer Free Unicode character explorer. Paste any text to break it down code point by code point — Unicode name and category, hex and decimal value, HTML entity, UTF-8 bytes and JavaScript escapes. Spots hidden and invisible characters. Runs entirely in your browser. How to use: 1. Paste your text: Drop any text into the box — plain ASCII, accented letters, emoji, currency symbols or non-Latin scripts all work. 2. Read each character: Every code point gets its own card or table row showing the glyph, Unicode hex value, category, block, decimal, HTML entity and UTF-8 bytes. 3. Reveal hidden characters: Keep the invisible-characters option on to surface zero-width joiners, non-breaking spaces and control codes that you cannot otherwise see. 4. Copy what you need: Use the per-character copy button for a single code point, or the bulk copy rows to grab the whole string as code points, HTML entities, UTF-8 hex or JavaScript escapes. FAQ: Q: What is a Unicode code point? A: A code point is the unique number Unicode assigns to a single character, written as U+ followed by a hexadecimal value — for example U+0041 is the letter A and U+1F600 is a grinning face emoji. It is the character's identity, independent of how it is stored in bytes. This tool shows the code point for every character you paste, along with its decimal equivalent. Q: How is a code point different from a byte? A: A code point is the abstract number of a character, while bytes are how that number is actually stored. In UTF-8, one code point becomes one to four bytes — ASCII letters use a single byte, most accented and European characters use two, most other scripts use three, and emoji and rarer characters use four. The explorer lists the exact UTF-8 bytes for each character so you can see the difference. Q: Why does an emoji count as more than one character sometimes? A: Many emoji are built from several code points joined together. A flag, a skin-tone variant or a family emoji is really a sequence of code points connected by zero-width joiners and modifiers. This tool iterates by code point, so it shows each piece of the sequence separately — which is exactly why a single visible emoji can take up several rows. Q: Can it find invisible or hidden characters? A: Yes. Zero-width spaces, zero-width joiners, non-breaking spaces, byte-order marks and control codes are all invisible on screen but still present in your text. With the invisible-characters option enabled, each one gets its own row with a placeholder glyph and its code point, so you can spot stray characters pasted from documents or used to disguise text. Q: What does the category mean? A: Every Unicode character has a general category such as uppercase letter, decimal digit, currency symbol, dash punctuation or non-spacing mark. The explorer derives this category using the browser's built-in Unicode property support, so the labels match the official Unicode database. Categories help you tell a real hyphen from an en dash, or a digit from a look-alike letter. Q: Is my text uploaded anywhere? A: No. All of the analysis — code points, categories, UTF-8 encoding and HTML entities — happens in your browser using built-in JavaScript and Unicode features. Nothing you paste is sent to a server, logged or stored, so it is safe for private or sensitive text. ### Counters & Analysis #### Word & Character Counter URL: https://geratools.com/word-character-counter Free word and character counter. Paste or type any text and get live counts for words, characters (with and without spaces), sentences, paragraphs, and estimated reading time at 200 words per minute. Runs entirely in your browser — your text is never uploaded. How to use: 1. Paste or type your text: Click the text area and start typing, or paste any text — an article, essay, email, or social media post. 2. Read the live counts: The six stat tiles update instantly as you type — words, characters with spaces, characters without spaces, sentences, paragraphs, and reading time. 3. Clear and start again: Click the Clear button to reset the text area and all counts to zero. FAQ: Q: How is reading time estimated? A: Reading time is based on a 200 words-per-minute average reading speed — a widely used benchmark for adult silent reading. The result is rounded up to the nearest second. Q: How are sentences counted? A: Sentences are counted by splitting on full stops, exclamation marks, and question marks, then filtering out empty fragments. It is a heuristic that works well for standard prose; abbreviations with dots may slightly inflate the count. Q: Is my text sent anywhere? A: No. All counting happens locally in your browser using JavaScript. Your text never leaves your device and is not stored, logged, or transmitted anywhere. Q: How are words counted? A: The text is trimmed and split on any run of whitespace (spaces, tabs, newlines), then the resulting tokens are counted. Hyphenated words like "well-known" count as one word; an em dash with spaces around it does not join words. Q: What is the difference between characters with and without spaces? A: "Characters with spaces" is the raw length of your text including every space, tab and line break. "Characters without spaces" removes all whitespace first, which is the figure most platforms mean when they quote a strict character limit. Q: How long is a 500-word essay to read out loud? A: At the 200 words-per-minute benchmark this tool uses, 500 words is about 2 minutes 30 seconds of silent reading. Spoken aloud is slower — roughly 130–150 wpm — so the same text takes closer to 3.5 minutes as a speech. Q: Does it count emoji and non-Latin characters correctly? A: Characters are counted by JavaScript string length, so most accented and non-Latin letters count as one. Some emoji and rare symbols are stored as two code units and may count as two characters — the same way many social platforms count them. #### Arabic Character Counter URL: https://geratools.com/arabic-character-counter Count Arabic text characters and UTF-8 bytes, with an option to strip tashkeel (harakat) and tatweel (kashida) before counting so diacritics and stretching don't inflate your totals. Runs in your browser. How to use: 1. Paste your Arabic text: Paste or type any Arabic text into the box; counts update live as you edit. 2. Choose whether to strip diacritics: Toggle "Exclude tashkeel" to remove harakat and tatweel before counting, so vowel marks don't inflate the character total. 3. Read the counts: The tool shows characters with and without spaces, UTF-8 bytes, and how many diacritic marks were stripped. FAQ: Q: What is tashkeel and why exclude it? A: Tashkeel (harakat) are the small vowel and pronunciation marks placed above or below Arabic letters, such as fatha, damma, kasra, shadda, and sukun. They are separate Unicode combining characters, so vocalised text has more characters than the same text unvocalised. Excluding them counts the base letters only. Q: Which characters count as diacritics here? A: The Arabic combining marks in the range U+064B to U+0652 (fathatan, dammatan, kasratan, fatha, damma, kasra, shadda, sukun), the superscript alef U+0670, and the Quranic annotation marks U+06D6 to U+06ED are treated as tashkeel. The tatweel (kashida, U+0640) stretching character is removed too. Q: Does it count bytes as well as characters? A: Yes. It reports the UTF-8 byte length, which matters for SMS, database column limits, and APIs. Most Arabic letters take two bytes in UTF-8, so the byte count is usually about double the character count. Q: Are spaces counted? A: Both ways. The tool shows total characters including spaces and a separate count excluding all whitespace, so you can match whichever limit you are checking against. Q: Does it modify my text? A: No. Stripping is applied only to compute the diacritic-free counts; the text in the box is never changed. Everything runs locally in your browser and nothing is uploaded. Q: Is لا (lam-alef) one character or two? A: Two. Lam-alef is rendered as one glyph but encoded as two Unicode code points (lam U+0644 + alef U+0627), so it counts as two characters. Only the legacy presentation form U+FEFB encodes it as a single code point, and modern text input does not produce that form. Q: Why do two identical-looking Arabic texts give different counts? A: Usually Unicode normalization or invisible characters. NFD-decomposed text carries hamza as a separate combining mark while NFC text uses precomposed letters like أ, and copied text often contains invisible directional marks (RLM U+200F, LRM U+200E, ALM U+061C) that count as characters. #### Arabic Syllable Structure Analyzer URL: https://geratools.com/arabic-syllable-structure-analyzer Break vocalised Arabic text into syllables and classify each as CV, CVV, CVC, CVVC or CVCC — light, heavy or superheavy — using consonant, short-vowel, long-vowel and sukun parsing for linguistics work. Runs in your browser. How to use: 1. Paste vocalised Arabic: Enter Arabic text with harakat (short-vowel marks) so the analyzer can find every vowel. 2. Read the syllable patterns: Each word is split into syllables labelled C, V and VV, such as CV or CVC. 3. Review the weight breakdown: The pattern counts show how many light, heavy, and superheavy syllables occur. FAQ: Q: What syllable types does Arabic have? A: Arabic syllables always begin with one consonant and a vowel. The core types are CV and CVV (open) and CVC, CVVC and CVCC (closed). CV is light, CVC and CVV are heavy, and CVVC or CVCC are superheavy and usually appear word-finally. Q: Why must the text be vocalised? A: Syllable structure depends on the short vowels, which Arabic normally leaves unwritten. Without harakat the analyzer cannot tell where vowels fall, so add fatha, damma, kasra and sukun for accurate results. Unvocalised letters are shown but cannot be fully syllabified. Q: How are long vowels detected? A: A long vowel is a short vowel immediately followed by its matching madd letter: fatha plus alef, damma plus waw, or kasra plus ya. The analyzer collapses that pair into a single VV nucleus, so a CVV or CVVC syllable is recognised. Q: How is shadda handled? A: Shadda marks a doubled consonant. Phonologically the geminate closes one syllable and opens the next, so the analyzer treats it as a coda on the first syllable plus an onset on the second, which is why a word with shadda gains a closed syllable. Q: Is this a full prosodic parser? A: No. It is a phonological approximation intended for teaching and quick analysis. Edge cases like hamzat al-wasl, definite-article assimilation, and pausal forms may not be modelled exactly, but the core CV parsing is correct for vocalised words. #### Chinese Paragraph Counter URL: https://geratools.com/chinese-simplified-paragraph-counter Count paragraphs and Chinese characters in Simplified Chinese text and estimate printed pages using the standard 500-character-per-page book convention. Runs entirely in your browser with no upload. How to use: 1. Paste your Chinese text: Paste or type Simplified Chinese text into the box, separating paragraphs with a blank line. 2. Read the paragraph and character counts: The tool counts paragraphs as blocks split by blank lines and counts CJK ideographs as the character total publishers use. 3. Check the page estimate: An estimated page count appears using the standard 500-characters-per-page convention for Chinese books. FAQ: Q: How are paragraphs counted? A: A paragraph is any block of text separated from the next by a blank line. A single line break inside a block is treated as a soft wrap, not a new paragraph, which matches how Chinese manuscripts and ebooks mark structure. Q: What counts as a character for the page estimate? A: Only CJK ideographs (Chinese characters) are counted toward the per-page figure, because that is the 字数 number Chinese publishers use. Latin letters, digits, spaces, and punctuation are excluded from the page math. Q: Why 500 characters per page? A: 500 characters per page is the long-standing convention for typeset Chinese books and is widely used to estimate length for manuscripts and contracts. Actual layout varies with font size and trim size, so treat the result as an estimate. Q: Does the tool send my text anywhere? A: No. All counting happens locally in your browser using JavaScript. Your text is never uploaded, stored, or sent to a server, so it is safe for confidential drafts. Q: Does it handle Traditional Chinese too? A: Yes. The character matcher covers the full CJK Unified Ideographs range, so Traditional characters are counted the same way as Simplified ones. The page estimate works identically for both scripts. #### Chinese Stroke Counter URL: https://geratools.com/chinese-stroke-counter Free Chinese stroke counter. Sums the standard stroke counts of every CJK character in a passage and shows a per-character breakdown, useful for calligraphy, handwriting practice and Chinese education. Runs in your browser. How to use: 1. Paste your Chinese text: Enter or paste any Chinese passage into the input box. Non-Chinese characters such as spaces and punctuation are ignored automatically. 2. Read the total: The tool sums the standard stroke count of every recognised character and shows the grand total along with the average strokes per character. 3. Inspect the breakdown: Each character is displayed with its individual stroke count as a subscript, and any character not in the table is marked with a question mark and excluded from the total. FAQ: Q: How are stroke counts determined? A: Each character has a canonical number of strokes defined by its standard writing form, the same count used in dictionaries and stroke-order charts. This tool stores those counts in a built-in table covering common Simplified Chinese characters and adds them up for your passage. Q: Why is a character marked with a question mark? A: A question mark means the character is not in the built-in stroke table. Rather than guess, the tool excludes it from the total and flags it so your count stays honest. The summary tells you exactly how many characters were skipped. Q: Are punctuation and Latin letters counted? A: No. Only CJK ideographs are counted. Spaces, punctuation, digits and Latin letters are ignored entirely, so the total reflects the brushwork in the Chinese characters alone. Q: Does the same character always have the same stroke count? A: Within a single standard, yes. However Simplified and Traditional forms of a character can differ in strokes, for example 国 has 8 strokes while the Traditional 國 has 11. This table uses the Simplified standard counts. Q: Is my text uploaded anywhere? A: No. The stroke table is embedded in the page and all counting runs locally in your browser. Nothing you type is sent to a server, so the tool works offline once loaded and is safe for private text. #### Danish LIX Readability Score URL: https://geratools.com/danish-readability-lix Applies the Swedish-origin LIX formula to Danish, widely used in Scandinavian education, computing word, sentence, and long-word counts live in your browser. How to use: 1. Paste your Danish text: Drop a paragraph or article into the input box. The LIX score recalculates as you type. 2. Read the LIX value: A single number appears with a plain-language label, from easy children's books to very difficult academic prose. 3. Simplify and re-check: Shorten sentences and replace long words, then watch the LIX value drop toward an easier band in real time. FAQ: Q: Is LIX the same in Danish and Swedish? A: Yes. The formula is identical because LIX was deliberately built to be language-independent. Danish schools use the same long-word and sentence-length inputs, so a Danish LIX of 40 means the same difficulty band as a Swedish one. Q: What counts as a long word? A: A long word has more than six letters, that is seven characters or more. Danish compound nouns are frequently long, so factual Danish prose tends to score a few points higher than equivalent English. Q: What LIX score should I aim for? A: Under 35 is easy and suits general readers. 35 to 45 is typical newspaper level. Above 55 is technical or legal. For public information in Danish, many style guides target under 40. Q: How are sentences counted? A: Sentence count comes from terminal punctuation such as periods, exclamation marks, question marks, and colons. Trailing text with no terminator still counts as one sentence. Q: Is my text uploaded anywhere? A: No. All counting and scoring runs locally in your browser. Nothing is sent to a server, stored, or logged, so private drafts stay private. #### English Syllable Counter URL: https://geratools.com/english-syllable-counter Count syllables in English words and text. The tool counts vowel clusters and adjusts for silent trailing e, consonant-plus-le endings and silent ed, showing total syllables, words and an average per word. How to use: 1. Paste your text: Type or paste any English word, line or paragraph into the text box. 2. Read the totals: The tool instantly shows the number of words, the approximate total syllables and the average syllables per word. 3. Check each word: Use the per-word breakdown to see how many syllables were counted for every word and spot any irregular cases. FAQ: Q: How does the syllable counter work? A: It uses a vowel-cluster heuristic. Each group of consecutive vowels (a, e, i, o, u and sometimes y) usually marks one syllable, so the tool counts those groups and then applies corrections for common English spelling patterns like silent letters. Q: Why might the count be wrong sometimes? A: English spelling is highly irregular, so no rule-based counter is perfect. Words with unusual pronunciation, foreign origin or silent letters can be off by one. The tool handles common cases — silent trailing e, consonant-plus-le endings and silent ed — but treats edge cases approximately. Q: How are silent letters handled? A: A silent trailing e (as in make or cake) is subtracted, but a consonant followed by le (as in table or little) keeps its syllable. A silent ed (as in walked) is removed, while a voiced ed after t or d (as in wanted) is kept, matching normal English pronunciation. Q: Is this useful for poetry like haiku? A: Yes. Counting syllables is essential for haiku (5-7-5), limericks and other metered forms. Use the per-word and total counts to check each line, but read the lines aloud too, since the heuristic is approximate for unusual words. Q: Does my text get uploaded anywhere? A: No. All counting happens locally in your browser using JavaScript. Your text is never sent to a server, stored or logged, so it is safe to paste private or unpublished writing. Q: How is the average syllables-per-word figure used in readability scores? A: Classic formulas like Flesch Reading Ease are built on it: 206.835 − 1.015 × (words per sentence) − 84.6 × (syllables per word). Plain English prose averages roughly 1.4–1.5 syllables per word; higher sustained averages indicate formal, latinate vocabulary that lowers the readability score. #### German Wiener Sachtextformel URL: https://geratools.com/german-readability-wiener Computes the Wiener Sachtextformel (WSTF first formula) from your German text, using the share of 3+ syllable words, average sentence length, share of long words and share of one-syllable words. Returns a school-grade readability level from 4 to 15. How to use: 1. Paste German text: Enter a representative German passage. Counting and scoring happen entirely in your browser. 2. Read the WSTF score: The tool returns the Wiener Sachtextformel value, which maps to a German school grade level. 3. Interpret the grade: Lower scores mean easier text; aim for 4 to 8 for general audiences and below 6 for broad public communication. FAQ: Q: What is the Wiener Sachtextformel? A: It is the standard readability formula for German non-fiction, developed by Richard Bamberger and Erich Vanecek. The result is a number that corresponds roughly to the German school grade needed to understand the text. Q: Which inputs does the formula use? A: The first formula uses four variables: MS, the percentage of words with three or more syllables; SL, the average sentence length in words; IW, the percentage of words longer than six letters; and ES, the percentage of one-syllable words. Q: What is the exact formula? A: WSTF = 0.1935·MS + 0.1672·SL + 0.1297·IW − 0.0327·ES − 0.875. MS, IW and ES are percentages of total words and SL is the mean number of words per sentence. Q: How do I read the result? A: The score approximates a German school grade. A value around 4 is easy primary-school text, 8 to 10 suits general adult readers, and 13 to 15 is difficult academic or technical German. Q: Why does German need its own formula? A: English formulas like Flesch are calibrated to English syllable and word-length patterns. German's long compound words inflate those metrics, so the Wiener Sachtextformel was calibrated specifically on German texts. #### Hebrew Biblical Vowel Pattern Analyzer URL: https://geratools.com/hebrew-biblical-vowel-analyzer Analyze the nikud vowel points in pointed Biblical Hebrew, naming each mark (qamatz, patah, tsere, segol, hiriq and more) with transliteration and vowel quality, plus a consonant and vowel count. Runs entirely in your browser. How to use: 1. Paste pointed Hebrew: Paste Biblical Hebrew text that already carries nikud vowel points. Unpointed text has no vowels to analyze. 2. Read the named marks: Each distinct vowel point is listed with its name, transliteration, and vowel quality. 3. Check the counts: The summary shows how many consonants and vowel points the text contains for quick verification. FAQ: Q: What are nikud? A: Nikud (niqqud) are the small dots and dashes added above, below, and inside Hebrew consonants to mark vowels. The Masoretes devised the system around the 7th to 10th centuries CE to preserve the traditional pronunciation of the Hebrew Bible, which is otherwise written with consonants only. Q: Which vowel marks does it recognize? A: It recognizes the full Tiberian set: sheva, the three hataf reduced vowels, hiriq, tsere, segol, patah, qamatz, holam, qubuts, qamatz qatan, and the dagesh or mappiq point. Each is reported by name with a transliteration and a short description of its quality. Q: How do I tell qamatz from qamatz qatan? A: They share the same long-a sign (a small T-shape under the letter), but qamatz qatan is pronounced as a short o in closed unstressed syllables. Unicode has a separate code point for qamatz qatan, so when a text uses it the tool reports it distinctly; otherwise an ordinary qamatz is shown with both readings noted. Q: Is the dagesh a vowel? A: No. The dagesh is a dot inside a letter marking gemination (doubling) or a plosive pronunciation, and the identical-looking mappiq marks a pronounced final he. The tool lists it because it is a nikud code point, but it is not counted among the vowel points in the summary. Q: Does my text leave the browser? A: No. The analysis reads Unicode combining marks locally in JavaScript. Nothing you paste is uploaded, logged, or stored, so private or unpublished texts stay on your device. #### Hebrew Word Frequency Counter URL: https://geratools.com/hebrew-word-frequency Tallies word frequencies in Hebrew text, optionally stripping niqqud vowel points and normalising final-letter forms, and can group words by an approximate shoresh (three-letter root). Ranks by count. Runs in your browser. How to use: 1. Paste Hebrew text: Enter or paste your Hebrew passage. The tool splits it on whitespace and punctuation, including Hebrew maqaf and geresh. 2. Choose normalisation: Toggle niqqud stripping and final-letter normalisation so vowel-pointed and final-form spellings of the same word are merged. 3. Read the ranked list: Words appear from most to least frequent, with optional shoresh grouping that clusters inflected and prefixed forms. FAQ: Q: How are Hebrew words counted? A: The text is split on spaces, line breaks, and punctuation such as the maqaf, geresh, and gershayim, then identical surface forms are tallied. With normalisation enabled, niqqud is removed and final letters are folded so the same word counts together regardless of pointing. Q: What is niqqud and why strip it? A: Niqqud are the small vowel and pronunciation points added beneath and beside Hebrew letters. Modern text is usually unpointed, so a pointed and an unpointed spelling of the same word should count as one. Stripping niqqud merges them. Q: What does final-letter normalisation do? A: Five Hebrew letters take a different sofit (final) shape at the end of a word: kaf, mem, nun, pe, and tsadi. Normalisation converts these final forms to their standard forms so a letter is counted the same wherever it appears. Q: How reliable is the shoresh grouping? A: True shoresh extraction needs a morphological analyser. This tool approximates it by stripping common prefixes (the definite article and the bet, kaf, lamed, mem, shin, vav, he clitics) and suffixes, then reducing toward three root letters. It clusters related words but is not a full analyser. Q: Does the text leave my browser? A: No. Tokenising, niqqud stripping, normalisation, and counting all run locally in your browser. Nothing is uploaded. #### Hindi Word Counter URL: https://geratools.com/hindi-word-counter Free Hindi word counter that splits Devanagari text on whitespace and the danda punctuation, ignoring conjuncts and stray symbols. Counts words, sentences, characters and lines locally in your browser. How to use: 1. Paste your Hindi text: Type or paste any Devanagari passage into the text box. 2. Watch the counts update: Words, sentences, characters and lines recalculate live as you type. 3. Use the figures: Copy the word count into essays, articles or assignment limits. FAQ: Q: How does it decide where one Hindi word ends and the next begins? A: It splits on whitespace and on the Devanagari danda (।) and double danda (॥), which mark clause and sentence ends. A token is only counted as a word if it contains at least one letter or digit, so stray punctuation is ignored. Q: Does a conjunct like क्या count as one word? A: Yes. Virama conjuncts are written without an internal space, so they stay inside a single token and are counted as one word — never split across the joining code points. Q: Are the danda marks counted as words? A: No. The danda and double danda are sentence separators, so a token like है। counts as a single word and also signals one sentence boundary. Q: Can I mix Hindi and English in the same text? A: Yes. Any token containing a letter or digit in any script counts as a word, so mixed Hindi-English passages are counted correctly. Q: Is my text sent to a server? A: No. All counting runs locally in your browser, so the text you paste never leaves your device. #### Italian Gulpease Readability Index URL: https://geratools.com/italian-readability-gulpease Compute the Gulpease Index, the readability formula built specifically for Italian using letters per word and sentences per word. Scores text 0 to 100 and maps it to school-education reading levels. Runs in your browser. How to use: 1. Paste the Italian text: Drop the passage you want to grade into the text box. The tool counts letters, words, and sentences automatically. 2. Read the Gulpease score: The index appears on a 0 to 100 scale, where higher numbers mean easier text. 3. Check the education level: The verdict tells you which school-education level can comfortably read the text, so you can simplify if needed. FAQ: Q: What is the Gulpease Index? A: Gulpease is a readability formula created for the Italian language by the GULP linguistics group. Unlike English formulas that count syllables, it uses letter count per word and sentence count per word, which suits Italian's longer words better. Q: What is the exact formula? A: The score is 89 plus the quantity 300 times the number of sentences minus 10 times the number of letters, all divided by the number of words. The result is clamped to the 0 to 100 range. Q: What score should I aim for? A: Aim for 80 or above for the general public and official communications. Scores from 60 to 80 suit readers with a middle-school education, and below 40 the text is hard for most people. Q: How do I make a text easier? A: Two levers raise the score: write shorter sentences, which increases the sentence count, and choose shorter words, which lowers the letter count. Both push the index upward. Q: Does it count punctuation as letters? A: No. Only alphabetic characters are counted as letters. Spaces, digits, and punctuation are excluded from the letter total, matching how the Gulpease formula is meant to be applied. #### Japanese Kanji Stroke Count Reference URL: https://geratools.com/japanese-kanji-stroke-order-reference Displays the stroke count for every kanji character in pasted text using a built-in client-side lookup table of common JLPT N5 to N1 kanji, with totals and unknown-character handling. How to use: 1. Paste your text: Type or paste any Japanese text into the box. Kana and punctuation are ignored automatically. 2. Read the per-kanji counts: Each kanji is listed with its stroke count from the built-in table; unknown kanji are flagged. 3. Check the total: The tool sums the strokes of all recognised kanji so you can gauge the writing effort. FAQ: Q: What is a kanji stroke count? A: The stroke count is the number of distinct pen movements needed to write a character in standard handwriting. It is fixed by convention for each kanji and is used to order characters in dictionaries and to teach correct writing. Q: Which kanji does this tool cover? A: It includes a curated table of common JLPT N5 through N1 kanji — the characters most learners encounter first. Any kanji not in the table is listed as unknown rather than guessed, so the counts you see are reliable. Q: How are stroke counts decided? A: Stroke counts follow the standard taught in Japanese schools and recorded in references like Kanjidic. A single continuous movement — even one that changes direction, like the corner of 口 — counts as one stroke. Q: Does it count kana or punctuation? A: No. Hiragana, katakana, Latin letters, numbers, and punctuation are skipped. Only CJK kanji characters are looked up and counted, so a sentence's total reflects kanji-writing effort only. Q: Is my text uploaded? A: No. The lookup table is bundled with the page and runs entirely in your browser. Nothing you paste is sent to a server. #### Japanese Mora Counter URL: https://geratools.com/japanese-mora-counter Count Japanese morae (haku) the way haiku and tanka are measured: each full kana is one mora, small ゃゅょ combine with the preceding kana, and ん, っ, and long-vowel ー each add a mora. Verify 5-7-5 structure entirely in your browser. How to use: 1. Paste kana text: Enter your haiku line or phrase in hiragana or katakana. 2. Let it count morae: Each line is counted by classical mora rules, with small kana merged and ん っ ー counted. 3. Check the structure: Per-line mora counts let you confirm a 5-7-5 haiku or 5-7-5-7-7 tanka. FAQ: Q: What is a mora? A: A mora, called haku or on in Japanese, is the rhythmic unit that poetry counts. It is not the same as a syllable: しゃ is one mora and one syllable, but とう is two morae because the long vowel adds a beat. Haiku are counted in morae, not syllables. Q: How are small kana counted? A: Small ゃ, ゅ, ょ (and their katakana forms) combine with the preceding full kana to form one mora, so きょ is a single mora. This is the yōon rule that keeps きょう at two morae rather than three. Q: Do ん, っ, and ー count? A: Yes. The moraic nasal ん, the geminate っ (sokuon), and the long-vowel mark ー each count as one full mora on their own. This is why しんぶん is four morae and コーヒー is four morae. Q: Why does my haiku count differ from the English syllables? A: English syllable counts often understate Japanese morae because long vowels and final ん add beats that English ignores. Counting morae is the authentic way to measure a Japanese 5-7-5, which is why translated haiku rarely keep the exact pattern. Q: Is my text uploaded? A: No. Mora counting runs locally in your browser. Nothing you enter is sent to a server. #### Japanese Paragraph Counter URL: https://geratools.com/japanese-paragraph-counter Count paragraphs and characters in Japanese text and estimate genko yoshi manuscript pages at the standard 400-character-per-page (400字詰原稿用紙) convention. Runs locally in your browser with no upload. How to use: 1. Paste your Japanese text: Paste or type Japanese text into the box, separating paragraphs with a blank line. 2. Read paragraph and character counts: The tool counts paragraphs as blocks split by blank lines and counts each non-whitespace character as one manuscript square. 3. Check the manuscript-page estimate: A genko yoshi page count appears using the standard 400-characters-per-page Japanese convention. FAQ: Q: What is a genko yoshi page? A: Genko yoshi (原稿用紙) is the squared Japanese manuscript paper used for handwriting and publishing. The standard sheet has 20 columns and 20 rows, giving 400 squares per page, which is why 400 characters equals one manuscript page. Q: How are paragraphs counted? A: A paragraph is a block of text separated from the next by a blank line. A single line break within a block counts as a soft wrap, not a new paragraph, matching how Japanese prose is typically structured. Q: What counts as a character? A: For manuscript pages, every non-whitespace character occupies one square: kana, kanji, and full-width punctuation each count as one. Whitespace is not counted, in line with how genko yoshi pages are filled. Q: Why 400 characters per page? A: The 400字詰原稿用紙 (400-character manuscript sheet) is the publishing and contest standard in Japan. Editors and competitions quote length in manuscript pages, so 400 characters per page is the reliable planning figure. Q: Is my text uploaded anywhere? A: No. All counting runs in your browser with JavaScript. Nothing is sent to a server or stored, so the tool is safe for unpublished drafts and confidential work. #### Japanese Sentence Counter URL: https://geratools.com/japanese-sentence-counter Count sentences in Japanese text. Splits on the ideographic full stop 。 (U+3002 maru), the full-width ！ and ？, their ASCII forms, and ellipses, while ignoring the enumeration comma 、 that separates clauses. Runs in your browser. How to use: 1. Paste your Japanese text: Type or paste any Japanese text into the box; counts update live as you edit. 2. Read the sentence count: The tool reports how many sentences the text contains, splitting on Japanese sentence-ending punctuation. 3. Review the extra stats: It also shows the character count (with and without spaces) and the average characters per sentence. FAQ: Q: What marks end a Japanese sentence? A: The main terminator is the ideographic full stop 。 (U+3002), called maru. Questions use the full-width ？ (U+FF1F) and exclamations the full-width ！ (U+FF01). The tool also accepts ASCII !?. and ellipses for mixed-script text. Q: Why does it count characters instead of words? A: Japanese is written without spaces between words, so word boundaries are ambiguous without a morphological analyser. Character count is the reliable, unambiguous unit, so the tool reports characters and characters-per-sentence. Q: Is the enumeration comma 、 treated as a sentence break? A: No. The Japanese enumeration comma 、 (U+3001, ten) separates list items and clauses within a sentence, not whole sentences. The tool ignores it when counting. Q: How are doubled ellipses like …… handled? A: Runs of terminating marks are collapsed, so a doubled ellipsis …… or a sequence like ！？ ends a single sentence rather than creating empty ones. Q: Does the tool upload my text? A: No. All counting runs locally in your browser, so nothing you paste is sent to a server. It is safe for confidential or unpublished Japanese text. #### Russian Flesch Readability Adaptation URL: https://geratools.com/russian-readability-flesch Scores Russian text readability using the Oborneva adaptation of the Flesch Reading Ease formula, with Russian-tuned constants (1.3 and 60.1). Counts words, sentences, and exact syllables from Cyrillic vowels, then maps the score to a difficulty band. How to use: 1. Paste Russian text: Enter or paste Cyrillic Russian text into the box. The score recalculates as you type. 2. Read the score: A number from 0 to 100 appears with a difficulty label; higher scores mean easier reading. 3. Inspect the breakdown: Review words per sentence and syllables per word to see what is driving the score up or down. FAQ: Q: What is the Oborneva adaptation? A: Maria Oborneva re-derived the Flesch Reading Ease constants for Russian in 2006 using large parallel corpora. The Russian formula is 206.835 minus 1.3 times words-per-sentence minus 60.1 times syllables-per-word, replacing the English 1.015 and 84.6 constants. Q: How are syllables counted in Russian? A: In Russian the number of syllables in a word equals the number of vowels, since every syllable has exactly one vowel nucleus. The tool counts the vowels а е ё и о у ы э ю я, which gives an exact syllable count without estimation. Q: What do the score bands mean? A: Roughly: 80 and above is very easy, 60 to 80 easy, 40 to 60 medium, 20 to 40 difficult, and below 20 very difficult. Higher is easier, the same direction as the original English Flesch scale. Q: Why does my score differ from an English Flesch tool? A: Because the constants differ. Russian words carry more syllables on average, so applying the English 84.6 syllable penalty would unfairly depress every Russian score. Oborneva's 60.1 corrects for this, giving comparable difficulty bands. Q: Is my text sent anywhere? A: No. The whole calculation runs in your browser in JavaScript. Your text is never uploaded or stored, so it is safe for unpublished or sensitive documents. #### Syllable Counter URL: https://geratools.com/count-syllables Free syllable counter that estimates the number of syllables in your words and text using a phonetic heuristic. Runs in your browser — nothing is uploaded. How to use: 1. Enter your text: Type or paste the words you want to analyze. 2. Read the totals: See the total syllable count and the number of words. 3. Check the per-word breakdown: Each word shows its individual syllable estimate next to it. FAQ: Q: How accurate is the syllable count? A: It uses a vowel-group heuristic with common adjustments. English spelling is irregular, so counts are a close approximation rather than a dictionary-perfect figure. Q: Is it useful for poetry like haiku? A: Yes, it gives a quick estimate for haiku, songs and meter, though you may want to verify tricky words by ear. Q: How does the tool decide where syllables fall? A: It counts vowel groups (runs of a, e, i, o, u, y) as syllable nuclei, then applies adjustments — for example trimming a silent trailing "e" and certain "es"/"ed" endings — and guarantees at least one syllable per word. Q: Why might it miscount some words? A: English spelling is irregular, so heuristics miss exceptions like silent vowels, diphthongs and unusual endings. Treat the count as a close estimate and verify tricky words by ear. Q: Does my text leave my device? A: No. The counting runs entirely in your browser with no uploads. #### Social Media Character Counter URL: https://geratools.com/character-counter-social Count characters in your post and see how many are left for X, Bluesky, Threads, Instagram, LinkedIn and more. Runs entirely in your browser — nothing is uploaded. How to use: 1. Type your post: Enter or paste the text you plan to publish. 2. Watch the live count: The total character count updates as you type, with emoji counted as single characters. 3. Check each platform: See remaining characters for each network, flagged red when you go over the limit. FAQ: Q: How are emoji counted? A: Characters are counted by Unicode code point, so most emoji count as a single visible character — close to how social platforms display length. Q: Which platforms are included? A: X / Twitter (free and Premium), Bluesky, Threads, Mastodon, Instagram, Facebook, LinkedIn posts and headlines, YouTube, TikTok and single-segment SMS. Q: What is the character limit for X / Twitter? A: A free X / Twitter post is limited to 280 characters; X Premium allows up to 25,000. This counter shows both, along with how many characters you have left. Q: How long can an Instagram caption be? A: Instagram captions can be up to 2,200 characters. The same limit applies to TikTok captions, while a LinkedIn post allows 3,000 and a single SMS segment is 160. Q: Is my draft uploaded? A: No — your text never leaves your browser; all counting is done locally. #### Word Frequency Counter URL: https://geratools.com/word-frequency-counter Free word frequency counter. Paste any text to see a ranked table of how often each word or phrase appears, with a stopword toggle, n-gram phrase mode and one-click CSV export. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your text: Drop an article, essay, transcript, set of reviews or any block of text into the box. It is analysed instantly as you type. 2. Choose words or phrases: Switch between single words and multi-word phrases (n-grams), and pick a phrase length from 2 to 5 words. 3. Filter the noise: Toggle stopword removal to drop common words like the, and, of, then read the ranked table sorted by frequency. 4. Export the results: Click Export CSV to download the full ranked table, or Copy table to paste it straight into a spreadsheet. FAQ: Q: What is a word frequency counter? A: A word frequency counter is a tool that reads a block of text and counts how many times each distinct word appears, then ranks the words from most to least common. It turns raw text into a frequency table so you can instantly see which terms dominate a document, which is useful for editing, SEO keyword research, linguistics and readability analysis. Q: What are stopwords and when should I remove them? A: Stopwords are extremely common function words such as the, and, of, to and is that appear in almost every sentence but carry little topical meaning. Turn the stopword toggle on when you want to surface the words that actually describe your subject; leave it off when you are studying writing style, grammar or the structure of the text itself. Q: What are phrases or n-grams? A: An n-gram is a run of n consecutive words. Switching to phrase mode counts two-word (bigram), three-word (trigram) or longer sequences instead of single words, which reveals repeated expressions, common collocations and key phrases that single-word counts miss entirely. Q: How is the percentage column calculated? A: Each term's percentage is its count divided by the total number of counted terms after your filters are applied, multiplied by one hundred. In phrase mode the total is the number of overlapping windows rather than the raw word count, so percentages always reflect the same population shown in the table. Q: Is there a limit on how much text I can analyse? A: There is no fixed character limit. Because everything runs locally in your browser the practical ceiling is your device's memory, so book-length documents of hundreds of thousands of words analyse fine on a normal laptop, usually in well under a second. Q: Is my text private? A: Completely. The text never leaves your device — all tokenising, counting, ranking and CSV generation happen in your browser with no network requests. Your draft is saved only in this browser's local storage so it survives a refresh, and you can clear it at any time. ### Clean & Transform #### Arabic Root Pattern Extractor URL: https://geratools.com/arabic-root-extractor Free Arabic root extractor. Paste Arabic words and the tool strips prefixes, suffixes, and template letters to recover their likely three-letter (triliteral) root using morphological pattern matching. Runs entirely in your browser. How to use: 1. Paste Arabic words: Enter one or more Arabic words separated by spaces or punctuation. Diacritics are stripped automatically before analysis. 2. Read the candidate roots: For each word the tool shows the likely three-letter root after removing prefixes, suffixes, and template letters. 3. Check the confidence flag: Words that resolve cleanly to three consonants are marked triliteral; weak or irregular words are marked uncertain. FAQ: Q: How does the extractor find a root? A: Arabic words are built from a root — usually three consonants (a جذر) — slotted into a template or pattern (وزن) modelled on the dummy root ف-ع-ل. The tool reverses this: it strips diacritics, removes common prefixes (the article ال, prepositions و ف ب ك ل, the future س) and suffixes (plural and pronoun endings like ون ين ات ة ه ها هم), then deletes the template's added letters and takes the first three remaining consonants as the candidate root. Q: Why is it called a heuristic and not exact? A: It uses pattern rules rather than a full dictionary, so sound (regular) triliteral roots resolve reliably, but weak roots (containing و, ي, or ء), hamzated, or geminate roots can lose or double a letter and may be flagged uncertain. Treat the output as a strong best guess, useful for study and lookup, not a guaranteed lemmatisation. Q: Does it handle the definite article and conjunctions? A: Yes. Leading clitics such as the definite article ال, the conjunctions و and ف, and the prepositions ب, ك, and ل are removed when doing so still leaves at least three letters, so والكتاب is reduced toward the root ك-ت-ب rather than being treated as a longer stem. Q: What is the confidence flag for? A: After stripping affixes and template letters, if exactly three consonants remain the word is labelled triliteral with high confidence. If more or fewer remain — common with weak or quadriliteral roots — it is labelled uncertain so you know to double-check that entry. Q: Is my text sent anywhere? A: No. All stripping and pattern matching run locally in your browser with JavaScript. Nothing is uploaded, stored, or logged, so you can analyse private word lists or study material safely. #### EPUB to Plain Text Extractor URL: https://geratools.com/epub-to-text Free EPUB to plain text extractor. Drop an .epub file and pull out all readable text in reading order, stripped of HTML, with a word count — ready for search, analysis, or notes. Runs entirely in your browser; no file is uploaded. How to use: 1. Drop the EPUB: Drag an .epub file onto the box, or click to choose one from your device. 2. Let it extract: The tool unzips the EPUB, reads the spine to get reading order, and strips HTML from each chapter into plain text. 3. Copy or download: Copy the combined text or download it as a .txt file, complete with a word count. FAQ: Q: How does EPUB to text extraction work? A: An EPUB is a ZIP of XHTML documents. The tool unzips it, reads the OPF spine to find the correct chapter order, removes HTML tags and scripts from each document, decodes entities, and joins the text together in reading order. Q: Will the chapters be in the right order? A: Yes. EPUBs define their reading order in the OPF spine, and the tool follows that order rather than the arbitrary order files happen to sit in the archive, so the extracted text reads top to bottom as the book intends. Q: Is formatting preserved? A: No — this produces plain text. Paragraph and heading breaks become newlines, but bold, italics, fonts, and images are dropped. That is ideal for search, word counts, and feeding text into other tools. Q: Is my ebook uploaded anywhere? A: No. The file is read and unzipped entirely in your browser using the native File and decompression APIs. Nothing is sent to a server, so your book stays private. Q: Why might extraction return little or no text? A: DRM-protected EPUBs encrypt their content and cannot be read as plain text. Image-only EPUBs (scanned comics, for instance) also contain no extractable text. The tool works on standard, DRM-free, text-based EPUBs. #### German Alphabetical Sort URL: https://geratools.com/german-collation-sort Sort German word and name lists correctly using DIN 5007-1 (umlaut treated as its base vowel) or DIN 5007-2 (umlaut expanded to ae, oe, ue), with ß handled as ss in both rules — for dictionaries, phone books and indexes. How to use: 1. Choose a DIN rule: Pick DIN 5007-1 for dictionary order or DIN 5007-2 for phone-book and name-list order. 2. Paste your list: Enter one word or name per line in any order. 3. Read the sorted list: The words are reordered by the chosen rule and can be copied with one click. FAQ: Q: What is the difference between DIN 5007-1 and DIN 5007-2? A: DIN 5007-1 is the dictionary rule: umlauts sort exactly like their base vowel, so ä = a, ö = o and ü = u. DIN 5007-2 is the phone-book rule: umlauts expand to two letters, so ä = ae, ö = oe and ü = ue, which separates names like Müller and Mueller. Q: How is ß sorted? A: In both DIN rules the sharp-s ß is treated as ss for ordering. So Straße and Strasse sort to the same position, just before words continuing with a different letter. Q: Which rule should I use for a list of surnames? A: Use DIN 5007-2 for phone books, member directories and any alphabetical name index. It is the rule German telephone directories follow, and it keeps the umlaut and digraph spellings of a name close together. Q: Why does Müller sort near Mueller in the phone-book rule? A: Under DIN 5007-2, Müller is treated as Mueller for comparison, so the two spellings collate to adjacent positions. Under DIN 5007-1, Müller is treated as Muller and sorts among the plain-u names instead. Q: Does sorting happen on my device? A: Yes. The list is sorted entirely in your browser using the selected DIN rule, so nothing you paste leaves your machine. #### Reverse Alphabet Cipher URL: https://geratools.com/reverse-alphabet Substitutes each letter with the letter at the mirror position in a reversed alphabet, so A becomes Z, B becomes Y, and so on. This is the Atbash cipher constructed explicitly, and it is its own inverse. Runs in your browser. How to use: 1. Enter your text: Type or paste any text into the input box; letters are mirrored and other characters are left as-is. 2. Read the result instantly: Each letter is replaced by the letter the same distance from the opposite end of the alphabet. 3. Reverse it for free: Run the output back through the tool to recover the original, since the cipher is its own inverse. FAQ: Q: Is the reverse alphabet cipher the same as Atbash? A: Yes. Atbash, originally an ancient Hebrew cipher, maps each letter to the one at the mirror position in the alphabet: A to Z, B to Y, and so on. This tool builds that mapping explicitly for the Latin alphabet, so the two are identical for English text. Q: Why is it its own inverse? A: Mirroring twice returns to the start. If A maps to Z, then applying the same rule to Z maps it back to A. So encoding and decoding are the exact same operation and you do not need a separate decode mode. Q: Does it handle case and punctuation? A: Yes. Uppercase stays uppercase and lowercase stays lowercase after mirroring, and any non-letter such as a space, digit, or symbol passes through unchanged. Q: What is the formula for each letter? A: For a zero-based letter index i from 0 to 25, the mirrored index is 25 minus i. Equivalently, the new character code is 90 minus (code minus 65) for uppercase, or 122 minus (code minus 97) for lowercase. Q: Is this secure? A: No. It is a fixed monoalphabetic substitution with no key, so anyone who recognises the pattern can reverse it instantly. It is useful for puzzles, light obfuscation, and teaching the idea of substitution. #### Reverse Words Transformer URL: https://geratools.com/reverse-words Reverses the order of words in your text while keeping each word and its punctuation intact. Splits on whitespace and rejoins with single spaces, line by line, so the original characters are never altered. Runs in your browser. How to use: 1. Enter your text: Type or paste the sentence, line, or paragraph whose word order you want to reverse. 2. See the reversed order: The tool reverses the words on each line as you type, keeping every word spelled normally. 3. Copy the result: Click copy to use the reordered text wherever you need it. FAQ: Q: Does this reverse the letters too? A: No. This tool reverses only the order of whole words; each word keeps its normal spelling and any attached punctuation. To reverse the letters inside each word, use the Each Word Reversed tool instead. Q: How does it treat multiple lines? A: Each line is reversed independently, so line breaks stay where they are. The last word of a line becomes the first word of that same line, and the paragraph structure is preserved. Q: What happens to punctuation attached to words? A: Punctuation stuck to a word travels with it. A trailing period on the last word stays attached to that word, so it moves to the front when the order flips. This is expected behaviour for word-order reversal. Q: How is whitespace handled? A: Words are split on any run of whitespace and rejoined with single spaces. Extra spaces, tabs, and multiple gaps are collapsed to one space, which keeps the reversed line clean and readable. Q: Is the original text changed in any way? A: Only the word order and spacing change. The characters within each word, including capitalisation and punctuation, are passed through exactly as you typed them. #### Russian Alphabetical Sort URL: https://geratools.com/russian-collation-sort Sort a list of Russian words into correct Cyrillic dictionary order, with ё placed between е and ж exactly as Russian collation requires. Paste a word list and copy the sorted output, processed entirely in your browser. How to use: 1. Paste your words: Enter one Russian word per line in the text box. 2. Choose direction: Leave it ascending for А to Я, or tick descending to reverse the order. 3. Copy the result: The list is sorted using Russian collation with ё ordered between е and ж, ready to copy. FAQ: Q: Where does ё sort in the Russian alphabet? A: In standard Russian dictionary order ё is collated immediately after е and before ж. It is treated as its own letter, not merged with е and not pushed to the end, which is exactly how this tool orders it. Q: Why not just use the browser default sort? A: A naive code-point sort places ё (U+0451) far away from е (U+0435), producing wrong dictionary order. This tool uses an explicit Russian alphabet ranking so the result matches how a Russian dictionary or phone book would order the words. Q: Is the sort case sensitive? A: No. Words are compared case-insensitively so Москва and москва rank together by letter. The original capitalisation of each word is preserved in the output. Q: How are non-letter characters handled? A: Digits, punctuation and spaces sort after all Cyrillic letters, so plain words come first. Comparison runs letter by letter and falls back to length when one word is a prefix of another. Q: Can I sort large lists? A: Yes. The sort runs locally in your browser and handles long word lists quickly. Nothing is uploaded, so it is safe for private or sensitive content. #### Extract Emails from Text URL: https://geratools.com/extract-emails-from-text Free extract emails from text tool — find every email address in pasted text, remove duplicates, lowercase, sort and export as a list or comma-separated. Runs entirely in your browser, nothing is uploaded. How to use: 1. Paste your text: Drop in any text, log, document or page content that contains email addresses. 2. Choose the output options: Toggle de-duplication, lowercasing, alphabetical sorting and comma-vs-newline separation. 3. Copy the address list: The matched addresses appear with a count — click Copy. FAQ: Q: What counts as a valid email here? A: It uses a pragmatic pattern — a local part of letters, digits and the common symbols (._%+-), an @, a dot-separated domain, and a two-or-more-letter top-level domain. This matches the vast majority of real addresses. Q: How accurate is the matching? A: The pattern favours precision over catching every exotic-but-legal address, so it rarely produces false positives. Unusual quoted or internationalised addresses may not be matched. Q: Is my text uploaded anywhere? A: No — all extraction happens locally in your browser and nothing is sent to a server. Q: Can it remove duplicate email addresses? A: Yes. Turn on de-duplication and each address appears once, even if it was repeated several times in the source text. Combine it with lowercasing so HELLO@x.com and hello@x.com count as the same address. Q: Does it work on a CSV, log file or email header dump? A: Yes. The tool ignores surrounding structure and simply scans for anything matching an email pattern, so you can paste raw logs, CSV rows, mailbox exports or web-page text and it pulls the addresses out. Q: Can I get the output as a comma-separated list? A: Yes. Switch the separator to comma to get a single line of addresses ready to paste into an email "To" field or a spreadsheet cell, or keep newline for one address per line. Q: Will it catch addresses with plus signs or dots, like name+tag@gmail.com? A: Yes. The pattern allows the common local-part symbols dot, underscore, percent, plus and hyphen, so tagged and dotted addresses such as name+tag@gmail.com are matched. ### Ciphers & Encoders #### ADFGVX Cipher URL: https://geratools.com/adfgvx-cipher Free ADFGVX cipher encoder and decoder. Substitutes each letter and digit through a 6×6 Polybius square keyed with ADFGVX coordinates, then applies a keyword-based columnar transposition — the exact two-stage process used by the German army in 1918. Runs entirely in your browser. How to use: 1. Enter the two keys: Provide a 36-character substitution key (the 6×6 square, normally A-Z plus 0-9) and a transposition keyword. The same two keys must be shared with the recipient. 2. Type your message: Type the plaintext to encrypt, or paste ADFGVX ciphertext to decrypt. Only the letters A, D, F, G, V and X are meaningful in the ciphertext. 3. Read the result: Encryption produces a stream of ADFGVX letters; decryption recovers the plaintext. The tool shows both stages so you can verify the substitution and the transposition. FAQ: Q: Why are only the letters ADFGVX used? A: These six letters were chosen because their Morse code patterns are very different from one another, which minimised transmission errors over noisy 1918 radio links. Each pair of these letters indexes one cell of the 6×6 Polybius square. Q: What is the size of the substitution square? A: It is a 6×6 grid holding 36 characters — the 26 letters A-Z plus the 10 digits 0-9. The earlier ADFGX cipher used a 5×5 grid (25 letters, I/J merged); ADFGVX added a sixth row and column so digits could be sent in the clear. Q: How does the columnar transposition step work? A: The ADFGVX pairs are written in rows under the transposition keyword. The columns are then read off in the alphabetical order of the keyword letters, scrambling adjacent pairs across the whole message. This fractionating effect is what made the cipher hard to break. Q: Is ADFGVX secure today? A: No. French cryptanalyst Georges Painvin broke it during the war, and modern computers crack it instantly. Treat it as a historical and educational cipher only, never for protecting real secrets. Q: What characters can I encrypt? A: By default only A-Z and 0-9 after the input is upper-cased and stripped of spaces and punctuation, because those are the only symbols the 6×6 square can represent. Anything outside the key is ignored during encryption. #### Affine Cipher Encrypt & Decrypt URL: https://geratools.com/affine-cipher Free Affine cipher tool that encrypts and decrypts text using the formula E(x) = (ax + b) mod 26. Picks coprime keys, computes the modular inverse, and runs entirely in your browser. How to use: 1. Choose encrypt or decrypt: Pick whether to scramble plaintext or recover the original message. 2. Set keys a and b: Choose a multiplicative key a that is coprime with 26 and an additive key b from 0 to 25. 3. Read the result: Output updates instantly. Use the same keys to decrypt back to plaintext. FAQ: Q: How does the Affine cipher work? A: Each letter is converted to a number 0-25, then encrypted with E(x) = (ax + b) mod 26. Decryption applies x = a^-1 (y - b) mod 26, where a^-1 is the modular inverse of a. Q: Why must key a be coprime with 26? A: If a shares a factor with 26 it has no modular inverse, so different letters can map to the same ciphertext and decryption becomes impossible. Valid values are 1, 3, 5, 7, 9, 11, 15, 17, 19, 21, 23 and 25. Q: What happens to spaces and punctuation? A: Only letters A-Z are transformed. Spaces, digits and punctuation pass through unchanged, and letter case is preserved. Q: Is the Affine cipher secure? A: No. With only 312 possible key combinations and vulnerability to frequency analysis, it offers no real security. Treat it as a learning exercise or puzzle, not encryption. Q: Is the Caesar cipher a special case of the Affine cipher? A: Yes. Setting a = 1 reduces E(x) = (x + b) mod 26 to a plain Caesar shift, so the Affine cipher is a strict generalisation of it. #### Arabic Morse Code Encoder URL: https://geratools.com/arabic-morse Free Arabic Morse code tool — convert Arabic letters to and from the ITU-standardised Arab Morse dot-dash sequences in your browser. Nothing is uploaded. How to use: 1. Choose encode or decode: Pick whether to turn Arabic letters into Morse or Morse back into Arabic. 2. Enter your text: For encoding, type Arabic words. For decoding, separate letters by spaces and words by three spaces or a slash. 3. Read and copy the result: The output updates instantly. Click Copy to grab it. FAQ: Q: What is Arabic Morse code? A: It is the ITU-standardised set of dot-dash sequences assigned to the 28 letters of the Arabic alphabet for telegraphy and radio. Each Arabic letter has its own code, distinct from the Latin set. Q: How are letters and words separated? A: Letters within a word are separated by a single space and words are separated by three spaces. When decoding you can also use a forward slash to mark word boundaries. Q: Does it handle hamza and letter variants? A: Yes. The bare hamza has its own code, and presentation variants such as alef with hamza, alef madda, taa marbuta and alef maqsura are mapped to the code of their base letter. Q: Is Arabic Morse case sensitive? A: Arabic script has no upper and lower case, so the question does not apply. Each letter maps to exactly one Morse sequence regardless of its position in the word. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser using a built-in lookup table, so nothing is sent to a server. #### ASCII Shift Cipher Encoder & Decoder URL: https://geratools.com/ascii-shift-cipher Free ASCII byte-shift cipher tool — adds a constant N modulo 256 to every byte of your text, covering all 256 values not just the 26 letters. Encrypt and decrypt with hex output in your browser, no upload. How to use: 1. Choose encrypt or decrypt: Encrypting adds the shift to every byte; decrypting subtracts it. Both wrap around modulo 256. 2. Set the shift N: Enter any whole number from 0 to 255. Values outside that range are taken modulo 256. 3. Enter text or hex and copy: Feed in UTF-8 text or paste hex bytes. The result is shown as hex, and as text when the bytes form valid UTF-8. FAQ: Q: How is this different from a Caesar cipher? A: A Caesar cipher shifts only the 26 letters and wraps within the alphabet. This cipher shifts the raw byte value of every character across all 256 possibilities, so a letter can become punctuation, a control byte or part of a multi-byte character. Q: Why is the output shown as hex? A: After shifting, the bytes often no longer form printable or valid UTF-8 text. Hex shows every byte unambiguously, so you can copy and later decrypt it exactly. When the shifted bytes do form valid UTF-8, the text version is shown too. Q: What does mod 256 mean here? A: Each byte holds a value from 0 to 255. Adding the shift can exceed 255, so the value wraps around: 250 plus 10 becomes 4, for example. Decrypting subtracts the same way, so the original byte is always recovered. Q: Can I decrypt something I pasted as hex? A: Yes. Switch the input format to hex and paste the bytes (spaces optional). The tool converts them back to bytes, subtracts the shift and shows the recovered text or hex. Q: Is an ASCII shift secure? A: No. With only 256 possible shifts, an attacker can try them all instantly, and shifting every byte by the same amount leaves frequency patterns intact. Use it for obfuscation, encoding puzzles and learning, not real protection. #### Beaufort Cipher Encoder & Decoder URL: https://geratools.com/beaufort-cipher Free Beaufort cipher tool — a reciprocal polyalphabetic cipher computing C = (K − P) mod 26 with a keyword. Encrypt and decrypt with the same operation. Runs entirely in your browser. How to use: 1. Enter a keyword: Type a keyword made of letters. It repeats across the message to drive the cipher. 2. Enter your text: Paste plaintext to encrypt, or ciphertext to decrypt — the Beaufort cipher uses the same operation for both. 3. Copy the result: The output updates instantly. Click Copy to grab the encrypted or decrypted message. FAQ: Q: How does the Beaufort cipher work? A: For each letter it computes C = (K − P) mod 26, where K is the current keyword letter and P is the text letter, both as 0–25. Subtracting the plaintext from the key letter is what makes Beaufort different from Vigenère. Q: Why can I decrypt with the same key? A: The formula is reciprocal. Because subtraction is symmetric here, applying C = (K − P) mod 26 to the ciphertext with the same keyword recovers the plaintext. There is no separate decrypt mode needed. Q: How is it different from the Vigenère cipher? A: Vigenère adds the key letter (C = P + K) and needs the inverse subtraction to decrypt. Beaufort subtracts the plaintext from the key (C = K − P), which is its own inverse, so encryption and decryption are identical operations. Q: What happens to spaces and punctuation? A: Non-letter characters such as spaces, digits and punctuation pass through unchanged and do not advance the keyword. Only letters consume a keyword position, and case is preserved. Q: Is the Beaufort cipher secure? A: No. As a classical polyalphabetic cipher it is vulnerable to Kasiski examination and frequency analysis once the key length is found. Use it for puzzles, learning and historical interest, not for protecting real secrets. #### Variant Beaufort Cipher URL: https://geratools.com/beaufort-variant Encrypts text with the variant Beaufort cipher, computing each letter as plaintext minus key modulo 26 — the inverse direction of standard Beaufort. Encryption and decryption use opposite operations. Runs in your browser. How to use: 1. Pick a direction: Choose encrypt to turn plaintext into ciphertext, or decrypt to recover plaintext using the same key. 2. Enter your keyword: Type a keyword made of letters; it repeats across the message and only advances on alphabetic characters. 3. Read the output: Each letter is computed as plaintext minus key modulo 26 when encrypting, and key plus ciphertext when decrypting. FAQ: Q: How does variant Beaufort differ from standard Beaufort? A: Standard Beaufort computes ciphertext as key minus plaintext, modulo 26. The variant Beaufort reverses the operands and computes plaintext minus key, modulo 26. This makes the variant equivalent to a Vigenère decryption step, so encryption and decryption are not the same operation as they are in standard Beaufort. Q: How do I decrypt a variant Beaufort message? A: Add the key back. Encryption is C = (P minus K) mod 26, so decryption is P = (C plus K) mod 26. Use the same keyword you used to encrypt and select the decrypt mode. Q: Does it preserve case and punctuation? A: Yes. Uppercase and lowercase letters keep their case after enciphering, and any non-letter character such as a space, digit, or punctuation mark passes through unchanged without consuming a key character. Q: What if my key contains non-letters? A: Non-letter characters in the key are ignored. Only the alphabetic characters of the keyword form the repeating key stream, so spaces or symbols inside the key are skipped. Q: Is this cipher secure? A: No. Like all classical polyalphabetic ciphers it is vulnerable to Kasiski examination and frequency analysis once the key length is found. Treat it as a puzzle or teaching tool, not real-world encryption. #### Book Cipher URL: https://geratools.com/book-cipher Free book cipher encoder and decoder. Replaces each word of your message with a line-and-word reference into a pasted reference text (the shared book), and decodes references back to words. A classic key-text cipher needing only an agreed passage. Runs entirely in your browser. How to use: 1. Paste the reference text: Paste the agreed passage or page of text. Both sender and receiver must use the exact same reference text for the references to line up. 2. Enter your message or codes: Type the message to encode, or paste line.word references to decode. Words are matched case-insensitively against the reference. 3. Read the result: Encoding outputs a reference for each word it can find; decoding turns each reference back into the word at that position in the reference text. FAQ: Q: How does a book cipher work? A: Both parties agree on a shared text — a book, article or page. Each word of the secret message is replaced by a reference pointing to a copy of that same word inside the shared text, such as its line number and position on the line. Anyone without the exact text cannot resolve the references. Q: What does a reference like 3.5 mean? A: In this tool a reference is written as line.word — so 3.5 means the 5th word on line 3 of the reference text. Decoding looks up that exact position and returns the word found there. Q: What if a word is not in the reference text? A: A word can only be encoded if it appears somewhere in the reference text. If a word is missing, the tool marks it so you know to choose a richer passage or reword the message. A larger reference text covers more vocabulary. Q: Why is the book cipher considered strong? A: Its strength comes from the secrecy and size of the key text rather than a fixed algorithm. Without the precise reference text an interceptor sees only numbers with no pattern. Historically it resisted analysis well, though reusing a famous public book weakens it. Q: What is the Ottendorf cipher? A: The Ottendorf cipher is a three-number variant of the book cipher using page, line and word (or letter). This tool uses a two-number line.word scheme, which is simpler and works directly on a pasted passage rather than a whole numbered book. #### Chaocipher Simulator URL: https://geratools.com/chao-cipher Free Chaocipher simulator — runs John F. Byrne's 1918 two-wheel permuting cipher with configurable left and right alphabets. Encrypt and decrypt in your browser, no upload, verified against the published test vector. How to use: 1. Choose encrypt or decrypt: Encrypting turns plaintext into ciphertext; decrypting reverses it using the same two starting wheels. 2. Set the left and right wheels: Enter the two 26-letter alphabets. Any letters you omit are filled in automatically to complete each wheel. 3. Enter text and copy: Only letters A–Z are enciphered. The output updates live; click Copy to grab it. FAQ: Q: What are the left and right wheels? A: The Chaocipher uses two alphabets imagined as wheels. The left wheel holds the cipher alphabet and the right wheel holds the plain alphabet. Their starting arrangements together form the secret key. Q: Why does the same letter encrypt differently each time? A: After every letter both wheels are permuted, so the substitution alphabet changes for the next character. This dynamic re-keying is what made the Chaocipher remarkably strong for a hand cipher. Q: How does one letter get enciphered? A: To encrypt, the plaintext letter is located on the right wheel and the letter at that same position on the left wheel becomes the ciphertext. To decrypt, the ciphertext letter is found on the left wheel and read off the right wheel. Q: What permutation happens after each letter? A: Each wheel is rotated so the matched letter sits at a fixed point, then one letter is extracted from a set position and reinserted lower down the wheel. The left and right wheels use slightly different extraction points, scrambling both alphabets. Q: Does the simulator match the real algorithm? A: Yes. It reproduces the steps Byrne's son published in 2010 and produces the canonical ciphertext OAHQHCNYNXTSZJRRHJBYHQKSOUJY for the famous WELLDONEISBETTERTHANWELLSAID example, then decrypts it back exactly. #### Dancing Men Cipher (Sherlock Holmes) URL: https://geratools.com/dancing-men-cipher Free Dancing Men cipher tool — encode and decode text using a consistent stick-figure substitution inspired by the Sherlock Holmes story, with flag-bearing figures marking word ends. Runs in your browser. How to use: 1. Choose encode or decode: Pick whether to turn letters into stick-figure glyphs or glyphs back into letters. 2. Enter your text: For encoding, type words. For decoding, paste the figure glyphs produced by this tool. 3. Read the result: The output updates instantly. Each letter maps to one figure, and the last figure of a word carries a flag. FAQ: Q: What is the Dancing Men cipher? A: It is a substitution cipher from the Sherlock Holmes story The Adventure of the Dancing Men, where each letter of the alphabet is drawn as a little stick figure in a different pose, and a flag held by a figure marks the end of a word. Q: Are these the exact original drawings? A: No. The original cipher is hand-drawn art with no Unicode equivalent. This tool uses a consistent one-to-one glyph mapping as a practical stand-in so you can encode and decode reliably online. Q: How are word breaks shown? A: In the story, the figure for the last letter of each word holds a small flag. Here a flag marker is appended to the final figure of every word so word boundaries survive encoding and decoding. Q: How did Holmes break it? A: Holmes used frequency analysis: the most common figure was likely E, and short repeated patterns hinted at common words. Because it is a simple substitution cipher, this attack works in general. Q: Is my text uploaded anywhere? A: No. Both encoding and decoding run entirely in your browser and nothing is sent to any server. #### Morse Code Encoder/Decoder URL: https://geratools.com/morse-code Free Morse code translator that converts letters, digits and punctuation to International (ITU) Morse dots and dashes and decodes them back, entirely in your browser. How to use: 1. Choose encode or decode: Pick whether to turn text into Morse or Morse back into text. 2. Enter your message: For encoding, type plain text. For decoding, type Morse using dots, dashes, spaces between letters and slashes between words. 3. Read and copy the result: The output updates instantly. Click Copy to grab it. FAQ: Q: What is International Morse code? A: International (ITU) Morse code represents each letter, digit and some punctuation as a sequence of dots and dashes. It is the standard variant used worldwide, replacing the older American Morse. Q: How are letters and words separated? A: A single space separates the Morse codes of two letters, and a forward slash (with spaces) separates words. This tool follows that convention so encoded output can be decoded back exactly. Q: Is Morse code case sensitive? A: No. Morse code has no concept of case, so A and a produce the same sequence. Decoded text is returned in uppercase. Q: What characters are supported? A: The 26 letters A–Z, digits 0–9, and common punctuation such as period, comma, question mark, slash and at-sign. Unsupported characters are skipped when encoding. Q: Is my text uploaded anywhere? A: No. The translation runs entirely in your browser using a built-in lookup table and nothing is sent to a server. #### Phonetic Alphabet Word Generator URL: https://geratools.com/phonetic-alphabet-word-generator Free phonetic alphabet word generator that spells out any word or letter set with NATO, a themed alternative, or your own custom code words. Great for reading codes aloud clearly over the phone or radio and for building branded spelling alphabets. Runs entirely in your browser. How to use: 1. Enter your text: Type the word, name, or code you need to spell out clearly. 2. Choose an alphabet: Pick the standard NATO alphabet or a themed set, or supply your own word for each letter. 3. Read the spelling: Each letter is expanded to its code word so you can read it aloud unambiguously. FAQ: Q: What is the NATO phonetic alphabet? A: It is the international radiotelephony spelling alphabet: Alfa, Bravo, Charlie, and so on. It assigns a distinct, hard-to-confuse word to each letter so spoken communication survives noise and accents. Q: Why use a custom phonetic alphabet? A: A themed alphabet — cities, fruits, or your brand vocabulary — can be more memorable or on-brand for an event. The generator lets you override any letter with your own word while keeping the read-aloud format. Q: How are digits and symbols handled? A: Digits are spoken as their number words and unrecognized characters are read literally or skipped. Only letters map to phonetic code words. Q: Is it case sensitive? A: No. Letters are matched case-insensitively, so spelling out a name works the same whether you type it upper or lower case. The original character is shown alongside its code word. Q: Does my text leave the browser? A: No. The spelling is generated entirely in your browser with JavaScript, so whatever you type stays on your device. #### Pigpen Cipher URL: https://geratools.com/pigpen-cipher Free pigpen (Masonic) cipher encoder and decoder. Maps each letter to the geometric shape of its cell in the two tic-tac-toe grids and two X grids, rendered as Unicode box symbols, and decodes the symbols back to letters. A historic monoalphabetic cipher. Runs in your browser. How to use: 1. Choose encode or decode: Encode turns letters into pigpen symbols; decode turns the symbols back into letters. Each letter maps to exactly one symbol. 2. Enter your text: Type a message to encode, or paste pigpen symbols to decode. Spaces and punctuation pass through unchanged. 3. Read and copy the result: The output shows the encoded symbols or the decoded plaintext. Use the copy button to put it on your clipboard. FAQ: Q: What is the pigpen cipher? A: The pigpen cipher, also called the Masonic or Freemason cipher, is a geometric substitution cipher that replaces each letter with a fragment of a grid. It was used by Freemasons in the 18th century to keep records private and appears in many puzzles and games. Q: How are the symbols assigned? A: Letters are placed into two tic-tac-toe grids and two large X (saltire) grids. Each letter takes the shape of the lines surrounding its cell. In the common scheme the second tic-tac-toe grid and the second X grid add a dot inside the same shapes, doubling the available symbols to cover all 26 letters. Q: Is the pigpen cipher secure? A: No. It is a simple monoalphabetic substitution, so it preserves letter frequencies and is broken with basic frequency analysis just like a Caesar cipher. Its value today is decorative, educational and recreational, not for real secrecy. Q: Why does the tool use box-drawing characters? A: True pigpen glyphs are line drawings, so this tool approximates each cell's shape with Unicode box-drawing characters and an added dot where the scheme requires one. This keeps the output as plain copyable text while still showing the distinct corner, edge and X shapes. Q: What happens to spaces and numbers? A: Spaces, digits and punctuation are not part of the pigpen alphabet, so they pass through unchanged in both directions. Only the 26 letters A-Z are substituted with symbols. #### Playfair Cipher Encrypt & Decrypt URL: https://geratools.com/playfair-cipher Free Playfair cipher tool that encrypts and decrypts letter pairs on a 5×5 keyword square. Implements the real same-row, same-column and rectangle rules with I/J merging, in your browser. How to use: 1. Choose encrypt or decrypt: Pick whether to encrypt plaintext pairs or recover them. 2. Enter a keyword: The keyword fills the start of the 5×5 square; the rest of the alphabet (I/J merged) follows. 3. Read the result: The square and output update instantly. Decrypt with the same keyword to restore the text. FAQ: Q: How does the Playfair cipher work? A: A 5×5 square is built from a keyword plus the rest of the alphabet, with I and J sharing a cell. The message is split into letter pairs and each pair is replaced according to its position in the square. Q: What are the three substitution rules? A: If both letters share a row, each is replaced by the letter to its right. If they share a column, each is replaced by the letter below. Otherwise they form a rectangle and each letter is replaced by the one in its own row but the other letter's column. Q: Why are X letters inserted? A: Playfair works on pairs, so a repeated letter in a pair (like the two letters in EGG) and any leftover single letter at the end are padded with X to keep every pair valid. Q: Why are I and J combined? A: A 5×5 grid holds only 25 cells but the alphabet has 26 letters, so I and J are merged into one cell. During decryption an I may therefore need to be read as a J from context. Q: Is the Playfair cipher secure? A: No. Although it resists simple single-letter frequency analysis better than a Caesar cipher, it was broken long ago and offers no protection against modern cryptanalysis. #### 3D Polybius Cube Cipher URL: https://geratools.com/polybius-3d-cube Encode text as XYZ coordinate triplets in a 3×3×3 Polybius cube holding 26 letters plus a period. Each character becomes three digits from 1 to 3, and decoding reverses it. A fun extension of the classic Polybius square. Runs in your browser. How to use: 1. Choose encode or decode: Select encode to turn text into coordinate triplets, or decode to turn triplets back into text. 2. Enter your text or triplets: For encoding, type letters A to Z and the period. For decoding, type space-separated three-digit triplets like 111 211. 3. Copy the result: The output box shows the converted text or coordinates, ready to copy. FAQ: Q: Why a 3×3×3 cube instead of the usual square? A: A classic 5×5 Polybius square holds 25 cells and must merge two letters such as I and J. A 3×3×3 cube has 27 cells, enough for all 26 letters plus one extra symbol (a period here) with no merging needed, while keeping each axis a single digit from 1 to 3. Q: How is a character turned into coordinates? A: Each character maps to an index from 0 to 26. That index is split into a layer (Z), a row (Y), and a column (X), each from 1 to 3, by treating it as a base-3 number. The output triplet is written X then Y then Z. Q: Is this a secure cipher? A: No. Like all classical substitution ciphers it is a fixed mapping with no key, so it is trivially broken by frequency analysis. It is a teaching and puzzle tool, useful for learning about coordinate encodings, not for protecting real secrets. Q: What happens to spaces and unsupported characters? A: When encoding, any character not in the 27-cell set (including spaces) is simply skipped, so the output is a clean stream of triplets. When decoding, a triplet that maps to no cell, or a malformed group, shows as a question mark. Q: How do I separate triplets when decoding? A: You can separate them with spaces, commas, or newlines, for example 111 211 321. The tool also accepts a continuous run of digits whose length is a multiple of three and splits it into triplets automatically. #### Polybius Square Cipher Encoder URL: https://geratools.com/polybius-square Free Polybius square tool that encodes letters into row/column number pairs on a 5×5 grid (A=11, Z=55) and decodes them back. I and J share a cell, and it all runs in your browser. How to use: 1. Choose encode or decode: Pick whether to turn letters into coordinate pairs or numbers back into letters. 2. Enter your text: For encoding, type words. For decoding, type number pairs from 11 to 55 separated by spaces. 3. Read the result: Output updates instantly. Click Copy to grab the coordinates or recovered text. FAQ: Q: How does the Polybius square work? A: Letters are placed in a 5×5 grid filled A to Z with I and J sharing one cell. Each letter is replaced by its row and column number, so A=11 and Z=55. Q: Why do I and J share a cell? A: A 5×5 grid has 25 cells but the alphabet has 26 letters, so I and J are combined into a single cell. When decoding, a result of I may stand for J depending on context. Q: How do I format text to decode? A: Enter two-digit pairs using digits 1 to 5, such as 22 15 42 11, with spaces between pairs. The tool also accepts runs of digit pairs joined together within a token. Q: What happens to spaces, digits and punctuation? A: When encoding, characters that are not letters are passed through unchanged. When decoding, tokens that are not valid coordinate pairs are left as they are. Q: Is the Polybius square secure? A: No. On its own it is a simple substitution that preserves letter frequencies and is trivial to break. Its real value is as a building block inside stronger ciphers like Bifid and ADFGVX. #### Porta Cipher URL: https://geratools.com/porta-cipher Encrypt and decrypt with the Porta cipher, a polyalphabetic scheme from 1563 using reciprocal alphabets keyed by a repeating keyword. Because each alphabet is its own inverse, the same key both encrypts and decrypts. Runs in your browser. How to use: 1. Enter a keyword: Type a keyword made of letters. It repeats across your message and selects which reciprocal alphabet each character uses. 2. Type your message: Enter the text to encrypt, or paste ciphertext to decrypt. Porta is reciprocal, so the same operation does both. 3. Copy the result: The result box shows the transformed text. Run it through again with the same keyword to recover the original. FAQ: Q: Why is the Porta cipher reciprocal? A: Each of its 13 alphabets swaps letters in pairs, so applying the same substitution twice returns the original letter. That means encryption and decryption are the identical operation: feed the ciphertext back in with the same keyword and you get the plaintext. Q: How does the keyword choose an alphabet? A: Key letters are grouped in pairs: A or B selects the first tableau row, C or D the second, and so on up to Y or Z for the thirteenth. The keyword repeats over the message, so each plaintext letter is enciphered with the alphabet for the matching key letter. Q: How is it different from the Vigenere cipher? A: Both are polyalphabetic and keyword-driven, but Vigenere uses 26 shifting alphabets and is not reciprocal, so encryption and decryption differ. Porta uses 13 reciprocal alphabets, always maps the first half of the alphabet to the second half and back, and is its own inverse. Q: Is the Porta cipher secure today? A: No. Dating from 1563, it is a historical polyalphabetic cipher broken easily with modern techniques such as Kasiski examination and frequency analysis once the key length is found. Use it for learning and puzzles, never for real protection. Q: What happens to spaces, digits, and punctuation? A: Only letters are enciphered. Spaces, digits, and punctuation pass through unchanged and do not consume a key letter, so the keyword stays aligned with the letters of your message. Letter case is preserved in the output. #### Pig Latin Generator URL: https://geratools.com/random-pig-latin-generator Translates English text into Pig Latin using the standard rules: move the leading consonant cluster to the end and add ay, or add way to vowel-initial words. Preserves case and punctuation. How to use: 1. Type English text: Enter any sentence or phrase into the input box. Each word is transformed individually while spaces and punctuation are kept in place. 2. Read the Pig Latin: The translated text appears instantly below, with capitalization matched to the original word so sentences still read naturally. 3. Copy the result: Copy the Pig Latin output to share in messages, games, or puzzles. FAQ: Q: What is Pig Latin? A: Pig Latin is a playful word game, not a real language, where English words are altered by a simple rule. Consonant-initial words have their starting consonants moved to the end, followed by ay, and vowel-initial words just get way or yay added. Pig becomes Igpay and Latin becomes Atinlay. Q: How are words that start with a vowel handled? A: Words beginning with a vowel (a, e, i, o, u) keep their letters in order and simply have way appended. So egg becomes eggway and apple becomes appleway. This tool uses the common way convention. Q: What about consonant clusters like 'str'? A: The entire leading consonant cluster moves to the end together. Street becomes eetstray and glove becomes oveglay. The cluster qu is treated as a unit, so quick becomes ickquay rather than uickqay. Q: Does it keep my capital letters and punctuation? A: Yes. Capitalization is matched to the original word, so a capitalized word stays capitalized and an all-caps word stays all-caps. Spaces, commas, and full stops are left exactly where they were. Q: Why does Pig Latin sound the way it does? A: Moving the opening sound to the end and tacking on ay obscures the start of each word, which is what makes spoken Pig Latin hard to follow at speed. It is a classic schoolyard cipher used for fun and light secrecy. #### Rosicrucian / Templar Cipher URL: https://geratools.com/rosicrucian-cipher Free Rosicrucian cipher tool — encode text using the Rose Cross pigpen variant where a 3x3 grid holds three letters per cell, told apart by a dot on the left, centre, or right. Runs in your browser. How to use: 1. Type your message: Enter the text you want to encode. Letters are read case-insensitively. 2. Read the cell and dot: Each letter shows which of the nine grid cells it lives in and whether its dot sits left, centre, or right. 3. Use or copy the notation: Copy the cell-and-dot notation to share, or draw the grid lines and dots by hand for a true pigpen look. FAQ: Q: How is the Rosicrucian cipher different from plain pigpen? A: Plain pigpen uses a grid plus an X to give each letter its own shape. The Rosicrucian variant packs three letters into each of nine cells and tells them apart by placing a dot on the left, centre, or right of the cell. Q: How many cells and dots are there? A: There is a 3x3 grid of nine cells, and each cell can hold three letters distinguished by dot position. Nine cells times three positions gives 27 slots, enough for the 26-letter alphabet with one spare. Q: How do I read a symbol? A: First identify which corner or centre cell the lines describe, then note the dot's position. Cell 1 with a left dot is A, the same cell with a centre dot is B, and with a right dot is C. Q: Is the Rosicrucian cipher secure? A: No. It is a simple monoalphabetic substitution with a fixed grid, so anyone who knows the layout can decode it instantly. It was used for privacy and symbolism, not strong secrecy. Q: Is my text uploaded anywhere? A: No. Encoding happens entirely in your browser and nothing is sent to any server. #### ROT-N Cipher (Custom Rotation) URL: https://geratools.com/rot-n Free ROT-N Caesar cipher — pick any shift from 1 to 25 to encode or decode text. N=3 is the classic Caesar cipher and N=13 is ROT13. Letters wrap A to Z; non-letters stay. Runs in your browser. How to use: 1. Choose encode or decode: Encoding shifts letters forward by N; decoding shifts them back by N to recover the original. 2. Pick the rotation N: Enter any shift from 1 to 25. Use 3 for the classic Caesar cipher or 13 for ROT13. 3. Enter your text and copy: The output updates instantly. Click Copy to grab the encoded or decoded message. FAQ: Q: What is the ROT-N cipher? A: ROT-N is the general Caesar cipher. Each letter is shifted N positions along the alphabet, wrapping from Z back to A. Choosing N lets you set how far the alphabet rotates, with ROT13 and the Caesar cipher being special cases. Q: How do I decode a message? A: Switch to decode mode and enter the same N that was used to encode. Decoding by N is the same as encoding by 26 minus N, so the tool simply shifts in the opposite direction to reverse the cipher. Q: Which N gives ROT13 or the Caesar cipher? A: N=13 is exactly ROT13, which is self-inverse. N=3 is the cipher attributed to Julius Caesar. Any value from 1 to 25 produces a valid rotation; 26 (or 0) would leave the text unchanged. Q: Does it change numbers or punctuation? A: No. Only the 26 ASCII letters are rotated, and their case is preserved. Digits, spaces and punctuation pass through unchanged. For a cipher that also shifts symbols, use ROT47. Q: Is the ROT-N cipher secure? A: No. With only 25 possible shifts an attacker can try them all in seconds, and letter frequency reveals the key quickly. Treat it as a puzzle or teaching cipher, not real encryption. #### ROT47 Encoder & Decoder URL: https://geratools.com/rot47 Free ROT47 tool — rotate every printable ASCII character (letters, digits and punctuation) by 47 places. Self-inverse like ROT13 but covers the full symbol range. Runs in your browser. How to use: 1. Type or paste your text: Enter the message to obscure, including any digits and symbols, or paste ROT47 text to reveal it. 2. Read the result: Every printable ASCII character is rotated 47 places instantly as you type. 3. Reverse it: ROT47 is self-inverse, so paste the output back to recover the original, then Copy. FAQ: Q: How is ROT47 different from ROT13? A: ROT13 only rotates the 26 letters. ROT47 rotates all 94 visible ASCII characters from code 33 (exclamation mark) to 126 (tilde), so digits and punctuation are scrambled too, producing a more thoroughly obscured result. Q: Why a rotation of 47? A: There are 94 printable characters in the chosen range. Half of 94 is 47, which makes the cipher self-inverse: rotating by 47 twice equals a full 94-step cycle, landing back on the original character. Q: What characters are left unchanged? A: The space character (code 32) and any control characters or non-ASCII text outside the 33 to 126 range pass through untouched. Everything visible and punctuation-like is rotated. Q: Is ROT47 secure encryption? A: No. Like ROT13 it has no key and can be reversed instantly by anyone, so it is only useful for hiding text from casual reading, puzzles and CTF challenges. Q: Is my text uploaded? A: No. All rotation happens locally in your browser and nothing is sent to a server. #### Russian / Cyrillic Morse Encoder URL: https://geratools.com/russian-morse Free Russian Morse code tool — convert Cyrillic letters to and from standard Russian Morse dot-dash sequences in your browser. Nothing is uploaded. How to use: 1. Choose encode or decode: Pick whether to turn Cyrillic letters into Morse or Morse back into Cyrillic. 2. Enter your text: For encoding, type Russian words. For decoding, separate letters by spaces and words by three spaces or a slash. 3. Read and copy the result: The output updates instantly. Click Copy to grab it. FAQ: Q: What is Russian Morse code? A: It is the set of dot-dash sequences used to send Cyrillic letters by telegraph and radio. Each of the 33 Russian letters maps to a code, many of which differ from the Latin Morse set. Q: How is the letter Ё handled? A: By convention Ё is transmitted using the same code as Е, a single dot. This tool maps Ё to Е automatically when encoding. Q: Are digits and punctuation supported? A: Yes. Digits 0 to 9 and the period, comma and question mark use the standard international Morse codes, which are the same in Russian Morse. Q: How are words separated? A: Letters within a word are separated by a single space and words by three spaces. When decoding you can also use a forward slash to mark word boundaries. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser with a built-in lookup table, so nothing is sent to a server. #### Braille Dot Bitmap Renderer URL: https://geratools.com/text-to-braille-bmp Render words as a bitmap built from Unicode Braille dot characters (U+2800–U+28FF). Each letter is drawn on a pixel grid and packed into Braille cells for compact, copy-paste dot art. Free, keyless, runs in your browser. How to use: 1. Type your text: Enter letters or digits. Lowercase is uppercased and characters not in the built-in font are skipped. 2. View the dot bitmap: Each character is drawn on a 5×5 pixel grid, and groups of 2×4 pixels are packed into single Unicode Braille characters. 3. Copy the dots: Click Copy to grab the Braille text, then paste it anywhere that supports Unicode — chat, bios, or code comments. FAQ: Q: Is the output an image or text? A: It is text. Each cell is a single Unicode Braille character from the range U+2800 to U+28FF, so you can copy and paste it like any other text — no image file is produced. Q: How are pixels turned into Braille? A: A Braille cell holds a 2-wide by 4-tall pattern of dots. The renderer slices the pixel grid into 2×4 blocks and sets the matching dot bits, then adds the result to the base code point U+2800. Q: Why do some characters disappear? A: Only A–Z and 0–9 are in the built-in 5×5 font. Lowercase is uppercased; punctuation and other symbols are skipped so the grid stays clean. Q: Will it display correctly everywhere? A: Most modern fonts include Braille glyphs, so it renders on the web, Discord, and many editors. A few older fonts lack them and will show boxes instead of dots. Q: Is this readable by a Braille display? A: Not meaningfully. The dots form a visual bitmap of the letters, not Braille spellings, so a refreshable Braille display would output the raw dot patterns, not the words. #### VIC Cipher (Soviet Spy) Simulator URL: https://geratools.com/vic-cipher Free VIC cipher simulator — runs the Soviet spy cipher's three signature stages: chain-addition key generation, a straddling checkerboard, and two keyed columnar transpositions. Encrypt and decrypt in your browser, round-trip verified. How to use: 1. Choose encrypt or decrypt: Encrypting turns text into grouped digits; decrypting turns the digit groups back into text using the same key. 2. Set the keyword and seed: The keyword mixes the checkerboard and the numeric seed drives the chain-addition key generator that orders the transpositions. 3. Enter text and copy: Output appears in five-digit groups. Type your message or paste the groups; Copy grabs the result. FAQ: Q: What was the VIC cipher? A: It was a hand cipher carried by Soviet intelligence agents in the 1950s and famously discovered in a hollow nickel coin. It was considered one of the strongest pencil-and-paper ciphers ever fielded because it layered substitution and transposition with a clever key generator. Q: What are the three stages this simulator runs? A: Chain addition expands a short numeric seed into a long key stream, a straddling checkerboard turns letters into a compact digit stream, and two keyed columnar transpositions then scramble those digits. Decryption reverses all three steps. Q: What is chain addition? A: It is a lagged-Fibonacci generator working modulo 10: each new digit is the sum of two earlier digits, dropping any carry. A short seed thus grows into a long pseudo-random digit stream that keys the rest of the cipher. Q: Does this reproduce the full historical procedure? A: It implements the three cryptographic components faithfully and reversibly, but it derives the keys directly from your keyword and seed rather than from the historical date, agent number and message-key bookkeeping, which only served to produce the same kind of keys. Q: Is the VIC cipher breakable? A: By hand it was effectively unbreakable for its era, and even the NSA could not read VIC traffic until a defector revealed the system. Against modern computers it is a classical cipher and should be treated as educational, not secure. #### Extended Vigenère (Full ASCII) URL: https://geratools.com/vigenere-extended Applies the Vigenère cipher over the full 95 printable ASCII characters (codes 32 to 126) rather than only the 26 letters, so spaces, digits, and punctuation are all enciphered. Runs entirely in your browser. How to use: 1. Choose encode or decode: Pick whether you want to encrypt plaintext or decrypt ciphertext that was produced with the same key. 2. Enter your key: Type a keyword or phrase made of printable ASCII characters; it repeats cyclically across the whole message. 3. Read the result: Every printable character shifts by its key character's position in the 95-character alphabet, modulo 95, and the output appears instantly. FAQ: Q: How is this different from a classic Vigenère cipher? A: Classic Vigenère uses a 26-letter alphabet and ignores spaces and punctuation. This extended version uses all 95 printable ASCII characters (codes 32 to 126), so spaces, digits, and symbols are enciphered too and the keystream advances on every character. Q: What characters can I use in the key? A: Any printable ASCII character from space (code 32) up to tilde (code 126). Each key character contributes a shift equal to its offset from code 32. Characters outside this range are not valid key material. Q: What happens to characters outside printable ASCII? A: Characters with codes below 32 or above 126 — such as newlines, tabs, or non-Latin letters — are passed through unchanged so the layout of multi-line text is preserved. Q: Is decoding just the reverse shift? A: Yes. Encoding adds the key offset modulo 95 and decoding subtracts it modulo 95. Using the exact same key for decode recovers the original text precisely. Q: Is this secure for real secrets? A: No. Vigenère, even over full ASCII, is a classical cipher that falls to frequency and Kasiski analysis. Use it for puzzles and learning, not for protecting sensitive data; use modern authenticated encryption for that. #### Wabun Code (Japanese Morse) Encoder URL: https://geratools.com/wabun-morse Free Wabun code encoder — convert Japanese katakana into the ITU Wabun Morse dot-dash sequences used for Japanese radiotelegraphy, with full handling of dakuten and small kana. Runs in your browser. How to use: 1. Type katakana: Enter Japanese text in katakana. The encoder maps each kana to its Wabun Morse sequence. 2. Read the dot-dash output: Each kana becomes a sequence of dots and dashes, separated by spaces between kana. 3. Copy the code: Copy the Wabun sequence to use in practice, study, or transmission notes. FAQ: Q: What is Wabun code? A: Wabun code is the system for sending Japanese by Morse. Instead of mapping the Latin alphabet, it assigns a unique dot-dash sequence to each katakana syllable, so a whole kana is one Morse character. Q: How are voiced sounds like GA or PA handled? A: Voiced (dakuten) and semi-voiced (handakuten) sounds are sent as the base kana followed by a separate dakuten or handakuten Morse mark. So GA is the code for KA followed by the dakuten mark. Q: Does Wabun share symbols with international Morse? A: It uses the same dots and dashes, but the meanings differ. A sequence that is a letter in international Morse usually represents a different kana in Wabun, so the two must not be mixed without a mode switch. Q: What about small kana and the long vowel mark? A: Standard Wabun does not have separate codes for small kana, so small forms are usually sent as their full-size kana. The long vowel mark and common punctuation have their own dedicated sequences. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser and nothing is sent to any server. #### XOR Cipher URL: https://geratools.com/xor-cipher Free XOR cipher tool. Applies a bitwise XOR between your text's UTF-8 bytes and a repeating key string, outputting hex; decrypt by XORing the hex back with the same key. Symmetric, self-inverse, and identical in both directions. Runs entirely in your browser. How to use: 1. Choose encrypt or decrypt: Encrypt takes plain text and outputs hex. Decrypt takes hex and recovers the text. Both use the same key because XOR is its own inverse. 2. Enter your key and text: Type a key string of one or more characters, then enter the text to encrypt or the hex to decrypt. The key repeats to cover the whole message. 3. Read the result: Encryption shows space-separated hex bytes; decryption returns the original UTF-8 text. Copy the result with the button. FAQ: Q: How does an XOR cipher work? A: Each byte of the message is combined with a byte of the key using the bitwise exclusive-OR operation. Because XOR flips bits, applying the same key twice returns the original value, so the same operation both encrypts and decrypts. Q: Why is the output shown in hexadecimal? A: XOR can produce byte values that are control characters or invalid text, which would not survive copy-paste. Encoding the ciphertext as hex makes every result safely printable and copyable; the decrypt step reads the hex back into bytes before XORing. Q: What is a repeating-key XOR? A: If the key is shorter than the message, it is repeated cyclically so every message byte has a key byte to XOR with. This is the same idea as a Vigenere cipher but at the bit level, and it is only secure if the key is as long as the message and never reused. Q: Is the XOR cipher secure? A: A repeating short key is weak — it can be broken with frequency analysis and the Kasiski or index-of-coincidence methods. Only a truly random key as long as the message and used once (a one-time pad) gives the XOR cipher provable secrecy. Q: Does XOR handle Unicode and emoji? A: Yes. This tool encodes both the text and the key as UTF-8 bytes before XORing, so multi-byte characters such as accents and emoji are processed correctly and round-trip back to the original on decryption. #### ROT13 Converter URL: https://geratools.com/rot13-converter Free ROT13 converter that encodes and decodes text by rotating each letter 13 places. ROT13 is its own inverse. Runs entirely in your browser; nothing is uploaded. How to use: 1. Paste your text: Type or paste the text you want to ROT13 into the input box. 2. Read the output: The ROT13 result appears instantly below as you type. 3. Copy the result: Click Copy to put the converted text on your clipboard. FAQ: Q: Do I need separate encode and decode modes? A: No. ROT13 is its own inverse, so applying it twice returns the original text. The same single operation both scrambles and unscrambles. Q: What happens to numbers and punctuation? A: Only letters A–Z are rotated 13 places. Digits, spaces and punctuation are left exactly as they are. Q: Is anything sent to a server? A: No. ROT13 runs entirely in your browser with JavaScript, so the text you enter never leaves your device. Q: Is ROT13 secure? A: No. ROT13 provides no security at all — anyone can decode it instantly. It is used to lightly obscure text, like spoilers, puzzle answers, or offensive jokes, so people only see it if they choose to decode it. Q: What is ROT13 commonly used for? A: Hiding spoilers and punchlines in forums and Usenet, obfuscating email addresses against simple scrapers, and puzzle/CTF challenges. It is a convention for "hide this unless you want to read it", not encryption. Q: Is ROT13 the same as a Caesar cipher? A: Yes — ROT13 is a Caesar cipher with a fixed shift of 13. The special property is that because 13 is half of 26, encoding and decoding are the same operation. Q: Does it keep uppercase and lowercase? A: Yes. Case is preserved: uppercase letters rotate within A–Z and lowercase within a–z, so the capitalisation of your text is unchanged. #### Caesar Cipher URL: https://geratools.com/caesar-cipher Free Caesar cipher tool to encrypt and decrypt text with any shift from 0 to 25. Runs entirely in your browser; nothing is uploaded. How to use: 1. Choose encrypt or decrypt: Select whether you are encrypting plain text or decrypting a ciphered message. 2. Set the shift: Enter the shift amount from 0 to 25 used to move each letter through the alphabet. 3. Copy the result: The output updates instantly; click Copy to grab it. FAQ: Q: What is the difference between a Caesar cipher and ROT13? A: ROT13 is simply a Caesar cipher with a fixed shift of 13. This tool lets you pick any shift from 0 to 25, so a shift of 13 reproduces ROT13 exactly. Q: How do I decrypt a Caesar cipher message? A: Switch to Decrypt and enter the same shift that was used to encrypt. The tool rotates each letter back by that amount to recover the original text. Q: What does a shift of 3 do? A: A shift of 3 — the cipher Julius Caesar himself reportedly used — turns A into D, B into E, and so on. The word HELLO becomes KHOOR. Q: Does the Caesar cipher change numbers, spaces or punctuation? A: No. Only letters A–Z and a–z are shifted. Digits, spaces, punctuation and symbols pass through unchanged, which preserves the layout of your text. Q: How do I break a Caesar cipher without the key? A: Because there are only 25 possible non-zero shifts, you can brute-force it by trying each shift until readable text appears, or use letter-frequency analysis to find the most likely shift. Q: Is the Caesar cipher secure? A: No. With only 25 keys it is trivially broken and offers no real protection. It is useful for puzzles, teaching and lightweight obfuscation, not for protecting sensitive data. Q: Why does the result wrap from Z back to A? A: The alphabet is treated as a 26-letter ring, so shifting past Z wraps to A (modulo 26). This keeps every output a valid letter. Q: Is my message uploaded anywhere? A: No. The cipher runs entirely in your browser with JavaScript, so your message never leaves your device. #### Binary to Text Converter URL: https://geratools.com/binary-to-text Free binary to text converter that decodes 8-bit binary bytes back into readable UTF-8 text, accepting spaced bytes or a continuous bit stream. Runs entirely in your browser; nothing is uploaded. How to use: 1. Paste your binary: Enter binary as space-separated bytes or one continuous stream of bits. 2. Read the decoded text: The bytes are decoded as UTF-8 and the text appears instantly below. 3. Copy the result: Click Copy to put the decoded text on your clipboard. FAQ: Q: How do I convert binary to text? A: Paste the binary and the tool groups it into 8-bit bytes, converts each byte to its character value, and decodes the result as UTF-8. For example 01000111 is the letter G. Q: Does my binary need spaces between bytes? A: Not necessarily. You can paste space-separated bytes, or one continuous bit stream whose length is a multiple of 8 — both are split into bytes automatically. Q: What if my continuous bit stream is not a multiple of 8? A: It cannot be split cleanly into bytes, so the tool reports that the length must be a multiple of 8. Add or remove bits, or use spaces to mark byte boundaries. Q: What if the binary is not valid text? A: The tool checks each group is binary, that each byte is within 0–255, and that the bytes form valid UTF-8. If any check fails it shows a clear error instead of garbled output. Q: Can it decode characters beyond plain ASCII? A: Yes. Multi-byte UTF-8 sequences decode correctly as long as the bytes are in the right order, so accented and non-Latin characters can round-trip. Q: What is the difference between this and binary to ASCII? A: For values 0–127 the result is the same. This tool goes further by decoding the bytes as UTF-8, so it also handles characters above the basic ASCII range. Q: Is my data uploaded anywhere? A: No. Decoding runs entirely in your browser, so the binary you paste never leaves your device. #### Binary to Emoji Converter URL: https://geratools.com/binary-to-emoji Free binary-to-emoji converter that encodes text as 8-bit binary using a chosen emoji pair, and decodes emoji binary back to text. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a direction: Pick "Text → Emoji binary" to encode or "Emoji binary → Text" to decode. 2. Pick an emoji pair: Select which two emoji represent 0 and 1. 3. Copy the result: The output updates instantly — press Copy to grab it. FAQ: Q: How is text turned into emoji? A: Each character is converted to its binary code point, padded to 8 bits, then every 0 becomes one emoji and every 1 becomes the other from your chosen pair. Spaces between bytes are preserved. Q: Which emoji pairs can I use? A: You can pick from red/blue circles, black/white circles, red/green squares, or thumbs down/up. The first emoji always represents 0 and the second represents 1. Q: How do I decode an emoji binary message? A: Switch to "Emoji binary → Text" and select the same emoji pair that was used to encode it, then paste the emoji string. The tool maps each emoji back to 0 or 1 and reads the bytes. Q: Why does decoding give the wrong text? A: Almost always because the emoji pair does not match the one used to encode. The 0 and 1 emoji must be identical to the original, or the bits flip and you get garbage. Q: Does it work with letters beyond English? A: It uses each character code point, so basic Latin letters and ASCII work cleanly. Characters above code 255 produce longer-than-8-bit codes that may not round-trip reliably in fixed 8-bit decoding. Q: Is this real encryption? A: No. It is a playful encoding for fun messages, not security. Anyone who knows the emoji pair can decode it. Q: Is anything uploaded? A: No. The conversion happens entirely in your browser and nothing is sent or stored. #### Phonetic Spelling Generator URL: https://geratools.com/phonetic-spelling-generator Free phonetic spelling generator that turns names, codes and references into NATO (Alpha Bravo Charlie) or police (Adam Boy Charles) phonetics, with text-to-speech. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose an alphabet: Pick the NATO/ICAO alphabet or the police (Adam Boy Charles) alphabet. 2. Type what to spell: Enter a name, code or reference and the phonetic spelling appears instantly. 3. Copy or speak it: Press Copy to grab the text, or Speak to hear it read aloud. FAQ: Q: What is the difference between the NATO and police alphabets? A: The NATO/ICAO alphabet uses words like Alpha, Bravo and Charlie and is standard for aviation and the military. The police alphabet uses Adam, Boy, Charles and is common in US law-enforcement radio. Q: Can it read the spelling out loud? A: Yes. Press Speak to use your browser's built-in text-to-speech to read the phonetic spelling aloud — useful for practising or dictating over the phone. Q: How are numbers handled? A: Numbers are spelled out in full alongside the letters, so a reference like A7 becomes "Alpha Seven", keeping the whole string unambiguous. Q: Why use a phonetic alphabet at all? A: Many letters sound alike on a noisy line — B, P, D, T, V, and so on. Replacing each letter with a distinct word (Bravo, Papa, Delta) removes that ambiguity, which matters for names, postcodes and confirmation codes. Q: Does case matter? A: A capital letter is shown with a capitalised phonetic word so you can convey case if needed, for example "Alpha" for A and lowercase styling for a. Q: When should I use the police alphabet instead of NATO? A: Use the police (Adam Boy Charles) alphabet if your audience expects US law-enforcement conventions; otherwise the NATO alphabet is the international default understood across aviation, the military and most call centres. Q: Is my text uploaded? A: No. The generator and speech run entirely in your browser and nothing is sent or stored. #### Atbash Cipher Encoder & Decoder URL: https://geratools.com/atbash-cipher Free Atbash cipher tool — encrypt and decrypt text by mirroring the alphabet, entirely in your browser. Nothing is uploaded. How to use: 1. Enter your text: Type or paste the message you want to convert. 2. Read the mirrored output: Each letter is swapped for its mirror — A↔Z, B↔Y — and the result appears instantly. 3. Copy the result: Click Copy to put the converted text on your clipboard. FAQ: Q: How does the Atbash cipher work? A: It mirrors the alphabet: A maps to Z, B to Y, C to X, and so on. Because the mapping is symmetric, the same operation both encrypts and decrypts. Q: Do I need a separate decrypt mode? A: No. Atbash is its own inverse, so running enciphered text back through the tool returns the original message. Q: Where did the Atbash cipher come from? A: Atbash originated as a Hebrew substitution cipher and is one of the oldest known ciphers. Its name comes from the first, last, second and second-to-last letters of the Hebrew alphabet (aleph-tav-bet-shin). Q: Is the Atbash cipher secure? A: No. It has no key and a fixed mapping, so it offers no real security and can be broken instantly by anyone who recognises it. Use it for puzzles, learning and word games, not for protecting data. Q: Is anything uploaded? A: No — the conversion runs entirely in your browser and nothing is sent to a server. #### Substitution Cipher Encoder & Decoder URL: https://geratools.com/substitution-cipher Free monoalphabetic substitution cipher — encrypt and decrypt text with a keyword-seeded cipher alphabet, entirely in your browser. Case is preserved and nothing is uploaded. How to use: 1. Choose encrypt or decrypt: Pick whether to encipher plain text or recover the original message. 2. Enter a keyword: Type a keyword to seed the cipher alphabet — its unique letters come first, then the rest of the alphabet in order. 3. Read the result: Type your text and the substituted output updates instantly. Click Copy to grab it. FAQ: Q: How is the cipher alphabet built from the keyword? A: The unique letters of the keyword (in order of first appearance) are placed at the start of the cipher alphabet, then the remaining unused letters follow in normal alphabetical order. Each plain letter maps to the cipher letter in the matching position. Q: What happens to repeated letters in the keyword? A: Only the first occurrence of each letter is used. For the keyword PEPPER the unique letters are P, E, R, so the alphabet starts PER and then continues with A, B, C and the rest. Q: Does it keep capitalisation? A: Yes. Upper and lower case are preserved, and digits, spaces, and punctuation pass through unchanged. Q: How do I decrypt a message I enciphered? A: Switch to decrypt and enter the same keyword. The tool inverts the mapping, so the original keyword always recovers the plain text exactly. Q: Is a keyword substitution cipher secure? A: No. Monoalphabetic ciphers are easily broken by frequency analysis because each letter always maps to the same replacement. Use it for puzzles, teaching, and fun — not for protecting real secrets. Q: Is anything uploaded? A: No — the cipher runs entirely in your browser and nothing is sent to a server. #### A1Z26 Cipher Encoder & Decoder URL: https://geratools.com/a1z26-cipher Free A1Z26 cipher tool — convert letters to numbers and back (A=1, Z=26) entirely in your browser. Nothing is uploaded. How to use: 1. Choose encode or decode: Pick whether to turn letters into numbers or numbers back into letters. 2. Enter your text: For encoding, type words. For decoding, type numbers like 7-5-18-1 with words separated by spaces. 3. Read the result: The output updates instantly. Click Copy to grab it. FAQ: Q: How does the A1Z26 cipher work? A: Each letter is replaced by its position in the alphabet: A=1, B=2, through to Z=26. Letters within a word are joined by hyphens and words are separated by spaces. Q: How do I format text to decode? A: Put hyphens between the numbers of a single word and spaces between words — for example, 7-5-18-1 decodes to "gera". Numbers outside 1–26 are passed through unchanged. Q: Is the A1Z26 cipher case sensitive? A: No. Both uppercase and lowercase letters map to the same position, so A and a both become 1. Decoded output is returned in lowercase. Q: What happens to spaces, digits and punctuation? A: Spaces separate words and are preserved. Any character that is not a letter (digits, punctuation) is passed through unchanged when encoding, and any number outside 1–26 is left as-is when decoding. Q: Is the A1Z26 cipher secure? A: No. It is a simple substitution scheme with no key, so anyone who recognises the pattern can decode it instantly. Treat it as a puzzle or a learning exercise, not real encryption. Q: Where is the A1Z26 cipher used? A: It is common in puzzle hunts, escape rooms, geocaching, CTF challenges and classroom cryptography exercises, where numbers like 8-5-12-12-15 stand in for words. Q: Is my text uploaded? A: No — the conversion runs entirely in your browser and nothing is sent to a server. #### Caesar Cipher Tool URL: https://geratools.com/caesar-cipher-tool Free Caesar cipher tool. Encrypt or decrypt text with an adjustable shift, see a live preview, and brute-force all 25 shifts ranked by English likelihood. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose encrypt or decrypt: Pick Encrypt to turn plain text into cipher text, or Decrypt to reverse it. 2. Set the shift: Drag the shift slider from 0 to 25, or tap a preset such as 3 or 13 (ROT13). 3. Type your text and copy the result: The output updates live as you type. Copy the result, or use the brute-force table to crack an unknown shift. FAQ: Q: What is a Caesar cipher? A: A Caesar cipher is one of the oldest known encryption methods, named after Julius Caesar who reportedly used it for private messages. It shifts every letter of the alphabet a fixed number of positions, wrapping from Z back to A. With a shift of three, A becomes D, B becomes E, and Z becomes C. Because the same shift is applied to every letter, it is a simple substitution cipher and very easy to break by hand. Q: How do I decrypt a Caesar cipher if I know the shift? A: Set the mode to Decrypt, dial the slider to the same shift that was used to encrypt, and paste the cipher text. The tool shifts each letter back by that amount, wrapping around the alphabet, and shows the original message instantly. Q: How do I crack a Caesar cipher when I do not know the shift? A: Use the brute-force panel. There are only 25 possible non-trivial shifts, so the tool tries them all and ranks each candidate by how closely its letter frequencies match natural English. The most likely plaintext appears at the top, usually revealing the answer at a glance. You can copy any candidate row directly. Q: What is ROT13 and how is it related? A: ROT13 is simply a Caesar cipher with a shift of 13. Because 13 is exactly half of 26, applying it twice returns the original text, which makes ROT13 its own inverse. Select the preset labelled 13 to use it. It is commonly used online to hide spoilers and punchlines rather than for real security. Q: Does the tool keep punctuation, numbers and capital letters? A: Yes. Only the 26 letters A to Z are shifted. Spaces, digits, punctuation and symbols pass straight through unchanged, and the original upper or lower case of each letter is preserved so the structure of your message stays readable. Q: Is the Caesar cipher secure, and is my text private? A: The Caesar cipher offers no real security because there are only 25 keys and it can be cracked in seconds, as this tool demonstrates. Treat it as a learning aid or a bit of fun, not protection for sensitive data. Your privacy here is fully protected though, because every calculation happens in your browser and no text is ever sent to a server. #### NATO Phonetic Alphabet Translator URL: https://geratools.com/nato-phonetic-translator Free NATO phonetic alphabet translator. Convert text to Alfa Bravo Charlie (and back), copy each style variant, read it aloud, and use the full reference table. Runs entirely in your browser — nothing is uploaded. How to use: 1. Pick a direction: Choose Text to NATO phonetic to spell something out, or NATO phonetic to Text to decode a phonetic message back into plain characters. 2. Type your text: Enter a name, code, postcode or any string. Each letter and digit is spelled out instantly; spaces separate words and unknown characters pass through unchanged. 3. Choose a style and copy: Switch between Standard, Lowercase, Dash-joined, one-per-line and Callsign styles, then copy the whole output or any single variant with its own copy button. FAQ: Q: What is the NATO phonetic alphabet? A: It is a spelling alphabet where each letter is assigned a clear, distinct word — Alfa for A, Bravo for B, Charlie for C, and so on. Formally the ICAO/NATO International Radiotelephony Spelling Alphabet, it lets people pass letters and numbers accurately over radio or phone where similar-sounding letters like M and N, or B and D, are easily confused. Q: Why is it spelled Alfa and Juliett, not Alpha and Juliet? A: ICAO deliberately spells Alfa and Juliett that way so speakers whose first language is not English still pronounce them correctly. Alpha could be read with a silent ph, and a single t in Juliet could go silent for French speakers. This translator outputs the official Alfa and Juliett spellings but also accepts Alpha, Juliet and Xray when you decode. Q: Can it decode phonetic words back into text? A: Yes. Switch the direction to NATO phonetic to Text, paste words like Golf Echo Romeo Alfa, and it reconstructs the original characters. Decoding is case-insensitive and tolerant of dashes, slashes and the one-per-line list format the encoder can produce. Q: How are numbers handled? A: Digits use the standard ICAO radio words. Most match plain English, but a few are pronounced differently on air to cut through noise — 3 is said TREE, 4 is FOW-er, 5 is FIFE and 9 is NIN-er. The reference table on the page shows every digit and its spoken form. Q: What are the different output styles for? A: Standard gives the familiar Alfa Bravo Charlie with spaces. Lowercase suits casual chat. Dash-joined writes Alfa-Bravo-Charlie for compact callsigns. One-per-line produces a vertical A = Alfa study list. Callsign shouts everything in capitals the way it is read on a radio net. Each has its own copy button. Q: Is anything I type sent to a server? A: No. The whole translator, the reference tables and the read-aloud feature all run locally in your browser using built-in web APIs. Nothing you enter is uploaded, logged or stored anywhere. #### Braille Translator URL: https://geratools.com/braille-translator Free braille translator. Convert text to Grade-1 Unicode braille and decode braille back to text, with capitals, numbers, a dot-grid preview and the full braille alphabet chart. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose a direction: Pick "Text to Braille" to encode, or "Braille to Text" to decode. The Swap button flips the current input and output in one click. 2. Type or paste your input: Enter ordinary text to convert, or paste Unicode braille cells to decode. The output updates live as you type, two ways. 3. Copy the variant you need: Use the per-variant copy buttons to grab the braille cells or the ASCII dot-grid preview. Press Tap dots to hear each cell as clicks. 4. Read the chart: Scroll to the alphabet and number charts to see every cell, its dot numbers and the capital and number indicators. FAQ: Q: Which braille grade does this translator use? A: It uses Grade 1, also called uncontracted braille, where every letter maps to exactly one cell. Capital letters are marked with the capital sign and runs of digits with the number sign. Grade 1 is the simplest, most universal form and the right starting point for learners. Q: How are capital letters shown in braille? A: A capital is written by placing the capital sign (dot 6) immediately before the letter cell. So an uppercase A becomes the capital sign followed by the cell for a, while a lowercase a is just the single a cell. The decoder reads that indicator and restores the capital automatically. Q: How are numbers handled? A: A run of digits begins with the number sign (dots 3-4-5-6). After it, the cells normally used for the letters a through j stand for the digits 1 to 9 and 0. Number mode ends at the next space, so 2026 and the year written as words never get confused. Q: Is the conversion fully reversible? A: Yes for letters, digits, spaces and the supported punctuation. Encode some text, copy the braille, decode it back, and you get the original string character for character. The tool even shows a live reversible or not-reversible status so you always know. Q: What about contracted Grade-2 braille? A: This tool is Grade 1 only, so it does not apply the word and letter contractions of Grade 2 braille (for example single cells that stand for whole words like and or the). Every character maps to its own cell, which keeps the output unambiguous and easy to decode. Q: What is the ASCII dot-grid preview for? A: Each braille cell is six dots arranged in two columns of three. The dot-grid preview draws those raised dots as a star-and-dot grid so you can see the physical pattern, sketch it on paper, or paste it into a plain-text document where the braille font is not available. Q: Is my text sent anywhere? A: No. The entire translation, the charts and the click playback run in your browser using plain JavaScript and the Web Audio API. Nothing is uploaded, logged or stored, so it is safe for private notes. ### Generators #### Acronym Generator URL: https://geratools.com/acronym-generator Generate memorable acronyms from a phrase by expanding each initial letter into themed words, or build a backronym from a target word. Runs fully in your browser using built-in word banks, ideal for naming programs, committees, and projects. How to use: 1. Pick a mode: Choose "Acronym from phrase" to abbreviate a phrase you already have, or "Backronym from word" to expand each letter of a target word. 2. Enter your text and theme: Type your phrase or word, then pick a word-bank theme such as business, tech, or motivational to flavour the expansion. 3. Generate and reroll: Read the result, then click Generate again to draw a fresh set of word choices until you find one you like. FAQ: Q: What is the difference between an acronym and a backronym? A: An acronym takes the first letters of an existing phrase to form a short name, such as NASA from National Aeronautics and Space Administration. A backronym starts from an existing word and invents a phrase whose initials spell it, like turning HOPE into Helping Other People Everywhere. Q: How does it choose the words? A: For each required letter the tool picks at random from a themed word bank of words starting with that letter. Picking again reshuffles those choices, so you can reroll until a phrase reads well. Q: What if no word starts with a needed letter? A: A few letters such as x or z have very few common starting words. When the bank has no match the tool inserts a clearly marked placeholder so you can supply your own word for that position. Q: Is anything sent to a server? A: No. All word banks and the generation logic are bundled into the page, so generation happens instantly in your browser and nothing you type is uploaded. Q: Can I use the result commercially? A: Yes. The output is just ordinary English words you can use freely for project names, programs, or product branding. Always check trademark availability before committing to a public name. #### Acrostic Name Poem Generator URL: https://geratools.com/acrostic-name-poem-generator Builds an acrostic poem from any name: each line begins with the next letter of the name and uses a positive descriptive phrase starting with that letter. A personalisable novelty generator for gifts, cards, classrooms, and social posts. Runs in your browser. How to use: 1. Type a name: Enter any first name, full name, or word. Letters become the first letter of each line; spaces are skipped. 2. Generate the poem: Click Generate. For each letter the tool picks a positive descriptive phrase that starts with that same letter. 3. Personalise and share: Regenerate for different phrasings, then copy the finished acrostic to drop into a card, gift tag, or social post. FAQ: Q: What is an acrostic poem? A: An acrostic is a poem in which the first letter of each line, read top to bottom, spells out a word or name. This generator builds one for any name you type, choosing a flattering phrase for each letter. Q: What if a letter is rare, like X or Z? A: The generator includes phrases for every letter of the alphabet, including tricky ones like X, Y, and Z, so even unusual names produce a complete acrostic without gaps. Q: Are uppercase and lowercase handled? A: Yes. The tool reads each letter case-insensitively to choose its phrase, but it capitalises the leading letter in the output so the acrostic reads cleanly down the left edge. Q: Can I use it for surnames or two-word names? A: Yes. Type the full name and the generator skips spaces, producing one line per letter. For a longer poem, enter first and last name together. Q: Is my name sent anywhere? A: No. The phrase library lives in the page and the poem is assembled in your browser. The name you type never leaves your device and nothing is stored. #### Anagram Generator URL: https://geratools.com/anagram-generator Free anagram generator that rearranges the letters of any word or phrase into real words using a built-in dictionary. Great for word games, puzzles, and creative names — runs entirely in your browser. How to use: 1. Enter your letters: Type a word, name, or set of letters into the input box. Letters are matched case-insensitively and spaces are ignored. 2. Choose a minimum length: Set the smallest word length you want returned so short, trivial words can be filtered out. 3. Read the matches: The tool lists every dictionary word that can be spelled from your letters, sorted longest first. Click Copy to grab the list. FAQ: Q: What counts as an anagram here? A: This tool finds every dictionary word whose letters are a subset of the letters you enter, where each letter is used no more than the number of times it appears in your input. That covers both full-length anagrams and shorter sub-words. Q: Where does the word list come from? A: A compact English word list is bundled directly into the page, so matching happens instantly and offline. It is not exhaustive, so very rare or proper-noun words may be missing. Q: Are spaces and punctuation used? A: No. Only letters A to Z are counted; spaces, digits, and punctuation are stripped before matching. Case does not matter, so "Listen" and "listen" produce the same results. Q: Does it find multi-word anagrams? A: No: it returns single dictionary words only. Rearranging a phrase into a multi-word anagram is a much larger search problem, so this tool focuses on fast, reliable single-word matches. Q: Is my input uploaded anywhere? A: No. The dictionary and the matching logic both run in your browser, so the letters you type never leave your device. #### ASCII Banner Generator URL: https://geratools.com/ascii-art-banner Generate large 7-row ASCII banner text from any word in your browser. A built-in hash-character font renders A–Z and 0–9 into copy-paste banners for terminals, login messages, and READMEs. Free and keyless. How to use: 1. Enter your banner text: Type a word or short phrase. Lowercase is converted to uppercase, and only A–Z, 0–9 and spaces are rendered. 2. Preview the banner: Each character is drawn as a 7-row tall block of hash characters, concatenated side by side into a tall single-line banner. 3. Copy it: Click Copy and paste the banner into a terminal MOTD, README code block, or any monospace surface. FAQ: Q: How tall are the letters? A: Every glyph is 7 rows tall and 5 columns wide, drawn with the hash character. The fixed height keeps all letters aligned across a single line. Q: Which characters can it render? A: Uppercase A–Z, digits 0–9, and spaces. Lowercase letters are uppercased automatically; any other symbol is skipped so it does not break alignment. Q: Why does my banner look misaligned? A: It must be displayed in a monospace font. Proportional fonts give each character a different width, which shears the banner. Use a terminal or a fenced code block. Q: What is a MOTD banner? A: A message-of-the-day banner is the ASCII art shown when you log into a server over SSH. This tool is a quick way to generate one without installing figlet or toilet. Q: How is this different from the FIGlet tool? A: The FIGlet-style tool uses a lighter line-drawing font; this banner tool uses a solid 7-row hash-filled font for a bolder, blockier look. Pick whichever suits the surface. #### Cat Lorem Generator URL: https://geratools.com/cat-lorem-generator Free cat lorem ipsum generator. Produce meow-filled placeholder text using feline vocabulary, cat facts and purr patterns. Generate paragraphs, sentences or words for pet-app mockups and cat-lover projects, instantly and in your browser. How to use: 1. Choose an amount and unit: Enter how much text you want and pick paragraphs, sentences or words. Paragraphs suit content blocks; words suit headings and labels. 2. Generate the meows: Press Generate to assemble fresh cat-flavoured filler sprinkled with real cat facts. Press again for a different mix from the same vocabulary. 3. Copy into your design: Click Copy and paste the meow-filled text into your pet-app prototype, cat-lover website or themed mockup as placeholder copy. FAQ: Q: What is cat lorem ipsum? A: It is a themed alternative to Latin Lorem Ipsum that fills layouts with feline vocabulary — meow, purr, whiskers, zoomies and the like, plus genuine cat facts. It plays the same placeholder role as ordinary filler text but suits pet apps, cat blogs and themed projects. Q: How is the text generated? A: Each sentence opens with a cat sound such as Meow or Purr, followed by a random run of feline words and roughly half the time a real cat fact like a group of cats is called a clowder. Sentences group into paragraphs. Everything is freshly assembled filler. Q: Are the cat facts real? A: Yes. The sprinkled facts are genuine, widely-cited tidbits about cats — for example that cats cannot taste sweetness and that they walk on their toes. They are woven into the filler for fun and flavour, not as a formal reference. Q: Will it produce the same text every time? A: For a given amount and unit the output is stable on each render because it uses a seeded random source. Press Generate to advance the seed and produce a fresh batch of meow-filled text. Q: Does any text leave my device? A: No. The generator runs entirely in your browser with no network calls. Your settings and the generated text stay local, so it works offline and your themed mockups remain private. #### Cookie Policy Generator URL: https://geratools.com/cookie-policy-generator Generates a full cookie policy — covering strictly necessary, analytics, marketing, and third-party cookie categories — from a short questionnaire about your site's actual cookies. Renders locally as copy-paste HTML or Markdown. Built for small businesses and indie developers who need a baseline-compliant policy without a lawyer. How to use: 1. Enter your site details: Provide your website name, the URL, and a contact email so the policy is correctly addressed and reachable for cookie questions. 2. Select which cookie categories you use: Tick the categories your site actually sets — strictly necessary, preferences, analytics, marketing — and name the key third-party services like Google Analytics or Meta Pixel. 3. Copy the policy: Copy the generated policy as HTML or Markdown and paste it into a /cookie-policy page on your site, then link to it from your cookie banner. FAQ: Q: Do I legally need a cookie policy? A: If your site uses non-essential cookies and you have visitors in the UK or EU, the UK PECR and EU ePrivacy rules require you to tell users what cookies you set and obtain consent for non-essential ones. A clear cookie policy plus a consent banner is the standard way to meet that obligation. Q: Is a generated policy enough on its own? A: The policy explains your cookies, but you still need a working consent mechanism: a banner that blocks non-essential cookies until the user agrees, and a way to withdraw consent. The policy and the banner work together. Q: What counts as a strictly necessary cookie? A: Cookies essential to deliver a service the user explicitly requested — session management, load balancing, security tokens, and shopping-cart state. These do not require consent, but you should still list them for transparency. Q: How often should I update it? A: Review it whenever you add or remove a tracking tool, change analytics providers, or alter retention. Many teams re-check quarterly. List concrete cookie names and durations so the policy stays auditable. Q: Does my information leave the browser? A: No. The policy is assembled entirely client-side from your answers. Nothing is uploaded or stored — you copy the finished HTML or Markdown yourself. #### Corporate Lorem Generator URL: https://geratools.com/corporate-lorem-generator Free corporate lorem ipsum generator. Produce buzzword-laden business placeholder text full of synergy, leverage and deliverables. Generate paragraphs, sentences or words for dashboard mockups and presentation slides, instantly in your browser. How to use: 1. Choose an amount and unit: Enter how much text you want and select paragraphs, sentences or words. Paragraphs suit slide notes; words suit chart labels and headings. 2. Generate the buzzwords: Press Generate to assemble fresh management-speak filler. Press again for a different blend of the same corporate vocabulary. 3. Copy into your mockup: Click Copy and paste the text into your presentation, dashboard prototype or pitch deck wherever you need realistic-looking business filler. FAQ: Q: What is corporate lorem ipsum? A: It is a themed alternative to Latin Lorem Ipsum that fills layouts with business jargon — synergy, leverage, deliverables, bandwidth and the like. It plays the same role as ordinary placeholder text but makes enterprise dashboard and slide mockups look convincingly on-brand. Q: How is the text put together? A: Sentences follow a we-need-to-verb-our-adjective-noun template, drawing the verb, adjective and noun from curated buzzword lists and sometimes opening with a connector like Going forward or Net-net. Sentences group into paragraphs, so the result reads like real management-speak without meaning anything. Q: Can I get a single buzzword phrase? A: Yes. Set the unit to words and choose a small count to get a short string of business vocabulary suitable for a KPI label, a chart title, or a slide heading rather than a full paragraph. Q: Will it produce the same text each time? A: For a given amount and unit the output is stable on each render because it uses a seeded random source. Press Generate to advance the seed and produce a fresh arrangement of the same vocabulary. Q: Does any text leave my device? A: No. The generator runs entirely in your browser with no network calls. Your settings and the generated copy stay local, so it works offline and your draft mockups remain private. #### Random Decision Generator URL: https://geratools.com/decision-generator Enter your options and let a random decision generator pick one for you with an animated reveal. Equal-weight, unbiased selection for restaurants, tasks, movies, or any tough choice. How to use: 1. List your options: Type each choice on its own line, or separate them with commas. Blank lines are ignored automatically. 2. Press Decide for me: Click the button and watch the animated reveal cycle through your options before landing on the winner. 3. Use or re-roll: Read the highlighted result; if you want a fresh draw, just press the button again for a new random pick. FAQ: Q: Is every option equally likely? A: Yes. Each valid option has the same probability of one divided by the number of options. The tool shows that percentage so you can confirm the odds before drawing. Q: How does the random selection work? A: It uses the browser's Math.random function to pick an index uniformly across your list. The animated cycling is purely cosmetic; the final landing index is itself a fresh uniform draw. Q: Can I use commas instead of new lines? A: Yes. The parser splits on both newlines and commas, then trims whitespace and drops empty entries, so either format (or a mix) works fine. Q: Is there a limit on how many options I can add? A: There is no hard limit. Practically, keeping the list to a few dozen options keeps the reveal readable and the odds meaningful for each choice. Q: Does it remember my choices? A: No. Nothing is saved or sent anywhere. Each decision is independent and the list lives only in the page until you reload. #### Email Subject Line Generator URL: https://geratools.com/email-subject-line-generator Generate email subject line variations using curiosity, urgency, personalization, and benefit formulas for newsletters, promotional, and transactional emails. Shows character count against the mobile cutoff and flags common spam-trigger words. How to use: 1. Enter your topic or offer: Type what the email is about, and optionally the recipient first name to personalize the lines or leave it blank to keep a merge token. 2. Choose the email type: Select newsletter, promotional, or transactional. Transactional reshapes the lines to be plain and specific, as those emails need. 3. Generate and check: Generate four angles of subject lines, check each one's character count and any flagged spam words, then copy the strongest. FAQ: Q: How long should an email subject line be? A: Aim for about 41 characters or fewer. That is roughly where many mobile email clients stop showing the subject and truncate it, and over half of email is opened on mobile. The tool shows each line's length and highlights those at 41 characters or under in green. Q: What words trigger spam filters? A: Aggressive sales language such as free, guarantee, act now, risk-free, 100%, and rows of dollar signs raise a message's spam score, especially in combination. The tool flags these words inline so you can rephrase. Modern filters weigh many signals, but avoiding obvious triggers still helps deliverability. Q: What are the four subject-line angles? A: Curiosity opens a loop the reader wants closed. Urgency uses a deadline to prompt action. Personalization uses the recipient's name or context. Benefit states the clear value of opening. Different lists respond to different angles, so test across them rather than always using one. Q: Should I personalize every subject line? A: Personalization can lift open rates, but only when it feels relevant rather than gimmicky. Using a first name works best when the rest of the email is genuinely tailored. If you only have a name and nothing else personal, a strong benefit or curiosity line often performs just as well. Q: Does the tool send my campaign data anywhere? A: No. Subject lines are generated in your browser from your inputs. Your topic, recipient name, and email type are never uploaded, so you can draft campaign ideas privately. #### Emoji Combo Generator URL: https://geratools.com/emoji-combo-generator Free emoji combo generator. Pick a mood like love, celebration, happy or cool and get random emoji combinations of any length, ready to copy into posts and messages. Runs entirely in your browser. How to use: 1. Choose a mood: Select a mood group such as love, celebration, happy, sad, cool, nature or food — or pick Surprise me for a random group. 2. Set the length: Use the slider to choose how many emojis each combo should contain, from 1 up to 8. 3. Generate and copy: Press Generate combos to get five fresh combinations, then copy any one you like with a single tap. FAQ: Q: How are the combinations built? A: Each mood maps to a curated group of compatible emojis. The generator randomly picks emojis from the selected group to fill a combo of your chosen length, so every press produces fresh, on-theme results. Q: Can I control how many emojis appear? A: Yes. A slider lets you pick from 1 to 8 emojis per combo. Shorter combos suit captions and message reactions, while longer ones make playful banners or post dividers. Q: Will the emojis display the same on every device? A: Emoji artwork is rendered by your device's operating system, so the exact look varies between iPhone, Android, Windows and Mac. The underlying characters are identical, so the meaning carries across, even if the style differs. Q: What does the Surprise me mood do? A: It picks a random mood group for each combo, mixing things up when you don't have a specific theme in mind. The emojis within a single combo still come from one coherent group. Q: Is anything uploaded? A: No. The emoji groups ship with the page and all randomness happens locally, so nothing you generate is sent anywhere and the tool works offline. #### Fake Data & Test PII Generator URL: https://geratools.com/fake-data-pii-generator Produces random fake identities — name, date of birth, UK National Insurance number, address, IBAN, phone, and email — for test databases, demo screenshots, and QA fixtures. Optionally seed the generator for reproducible records. All generation is local; no data is sent anywhere. How to use: 1. Choose how many records you need: Set the record count and optionally a seed. A fixed seed reproduces the exact same records every time, which is handy for stable test fixtures. 2. Generate: Click Generate to create fictional identities locally in your browser. Each record includes a name, DOB, NI number, address, IBAN, phone, and email. 3. Copy as JSON or CSV: Copy the output as JSON or CSV and paste it straight into your test database, seed script, or demo screenshot. FAQ: Q: Is any of this data real? A: No. Every value is randomly assembled from generic name and street word-lists and synthetic number formats. The data is structurally valid (correct formats and check digits) but does not correspond to any real person, account, or address. Q: Are the IBANs and NI numbers valid? A: They follow the correct format and pass the relevant check — the IBAN passes the ISO 13616 MOD-97 checksum, and the National Insurance number avoids the disallowed prefixes and suffixes. They are format-valid placeholders, not issued to anyone. Q: What is the seed for? A: Seeding makes generation deterministic: the same seed and count always produce the same records. This lets test suites assert against stable fixtures and lets teammates reproduce the exact dataset you used. Q: Can I use this for production data? A: No. It is intended for testing, QA, demos, and documentation. Because the data is fictional it is safe to commit to repositories and share in screenshots without leaking real PII. Q: Does anything leave my browser? A: No. Generation runs entirely client-side with a small pseudo-random generator. There are no network requests, so the fake records are never transmitted or logged anywhere. #### Hashtag Generator URL: https://geratools.com/hashtag-generator Free hashtag generator. Enter a topic or keywords and get up to 30 relevant hashtag suggestions built from real community, content and call-to-action patterns. Copy them all in one click. Runs entirely in your browser. How to use: 1. Enter your topic: Type one or more keywords that describe your post, separating distinct topics with a space or comma. 2. Review the suggestions: The tool generates base tags plus combinations with common community, content and call-to-action modifiers. 3. Copy and refine: Copy all hashtags in one click, then trim the list to the most relevant tags before posting. FAQ: Q: How are the hashtags generated? A: The tool cleans your words into valid hashtag form (letters and digits only), then combines them with common real-world modifiers such as community, tips, daily, oftheday and trends, plus a camelCased multi-word tag. Q: Are these real, popular hashtags? A: They follow the patterns of widely used hashtags, but the tool does not check live popularity. Treat them as a starting point and verify that a tag actually exists and has relevant posts before relying on it. Q: How many hashtags should I use? A: It depends on the platform. Instagram allows up to 30 but many creators find 5 to 15 focused tags perform best; X and LinkedIn favour just 1 to 3. Pick the most relevant from the list rather than using everything. Q: Why are spaces and punctuation removed? A: Hashtags cannot contain spaces or most punctuation. The tool strips those characters and lowercases each word so every suggestion is a valid, postable tag, while still offering a camelCase variant for readability. Q: Does it send my topic anywhere? A: No. All processing is pure string transformation in your browser, so your topic and the generated tags never leave your device. #### Hipster Lorem Generator URL: https://geratools.com/hipster-lorem-generator Free hipster lorem ipsum generator. Produce ironic, artisan-flavoured placeholder text built from craft, foodie and indie vocabulary. Generate paragraphs, sentences or words for design mockups and prototypes, instantly and in your browser. How to use: 1. Choose an amount and unit: Enter how much text you want and pick paragraphs, sentences or words. Use a few paragraphs for a content block or a handful of words for a heading. 2. Generate the text: Press Generate to build fresh hipster-flavoured filler. Press it again for a different mix from the same vocabulary. 3. Copy into your design: Click Copy to place the text on your clipboard, then paste it into your mockup, prototype, or CMS draft as placeholder copy. FAQ: Q: What is hipster lorem ipsum? A: It is a playful alternative to classic Latin Lorem Ipsum that swaps in ironic hipster vocabulary — words like artisan, kombucha, fixie and small-batch. It fills the same role as standard placeholder text but adds personality to mockups for cafes, lifestyle brands and indie projects. Q: How is the text generated? A: Words are drawn at random from a curated hipster word list and assembled into sentences of varied length, with occasional commas for rhythm. Sentences are grouped into paragraphs. Nothing is copied from real articles — every passage is freshly assembled filler. Q: Can I generate just a few words for a headline? A: Yes. Switch the unit to words and set a small count to get a short phrase suitable for a heading, button label or tagline placeholder rather than a full paragraph. Q: Is the output the same every time? A: A given amount and unit produces a stable result on each render thanks to a seeded random source. Press Generate to advance the seed and get a brand-new arrangement of the same vocabulary. Q: Does this send anything to a server? A: No. The generator runs entirely in your browser. Your settings and the text it produces never leave your device, so it works offline and keeps your mockups private. #### Initialism / Acronym Generator URL: https://geratools.com/initialism Builds an initialism or acronym by taking the first letter of each word in a phrase. Optionally uppercase the result, skip small words like of and the, and add periods between letters. Runs in your browser. How to use: 1. Enter a phrase: Type or paste the full phrase or organisation name you want to abbreviate into the input box. 2. Choose your style: Pick whether to uppercase the letters, skip small connecting words, and place periods between letters. 3. Copy the acronym: The generated initialism appears instantly below and can be copied with one click. FAQ: Q: What is the difference between an acronym and an initialism? A: An initialism is read letter by letter, like FBI. An acronym is pronounced as a word, like NASA. Both are built the same way, by taking the first letter of each word, so this tool generates either kind. Q: Why skip small words? A: Real-world acronyms often drop short connecting words. North Atlantic Treaty Organization becomes NATO, not NATTO, because of and the style omits low-content words. Turn the option on to mimic that convention. Q: What happens with punctuation or numbers? A: Leading punctuation on a word is ignored, and the first letter or digit found is used. A word like 3D contributes a 3, so codes and model names are handled sensibly. Q: Does the order of words matter? A: Yes. Letters are taken in the same order the words appear, so the acronym preserves the phrase's sequence. Rearranging the input changes the result accordingly. #### Name Mashup Generator URL: https://geratools.com/name-mashup-generator Blend two names or words into unique portmanteau mashups using several real blending algorithms — prefix-suffix joins, syllable splits, and overlap merges. Fun for couple names, band names, and fusion product naming. Runs in your browser. How to use: 1. Enter two names: Type the first and second name or word you want to blend together. 2. Generate mashups: Click Generate to produce a set of portmanteau blends using several different combining methods. 3. Copy a favourite: Pick the blend you like best and copy it to use as a couple name, band name, or product name. FAQ: Q: How are the mashups created? A: The tool applies several real portmanteau methods: joining the front of one word to the back of the other, splitting on the first vowel boundary, and merging on a shared overlapping letter. Each method produces a different candidate. Q: What is a portmanteau? A: A portmanteau is a single word made by blending the sounds and meanings of two others, such as brunch from breakfast and lunch, or smog from smoke and fog. This tool generates portmanteaus from any two inputs you provide. Q: Why do some blends look better than others? A: Different methods suit different word pairs. A shared letter between the two words produces a clean overlap merge, while a vowel-boundary split tends to read more smoothly. Generate the full set and pick the one that flows best. Q: Can I blend more than two words? A: The tool focuses on two inputs because portmanteaus are classically a blend of two words, which keeps the results readable. To combine three, blend two first, then feed the result back in as one of the inputs. Q: Is the order of the names important? A: Yes. Some methods take the front of the first word and the back of the second, so swapping the order changes the result. Try both orders and compare — one direction usually sounds noticeably better. #### Raffle Draw Generator URL: https://geratools.com/raffle-draw-generator Paste your participants and draw winners sequentially without replacement for a fair raffle. Perfect for social media giveaways, event prize draws, and classroom rewards, with first, second, and third place order. How to use: 1. Add participants: Enter each entrant on its own line or separate them with commas. Duplicate identical entries are merged automatically. 2. Set the number of winners: Choose how many winners to draw, up to the number of unique participants. 3. Draw winners: Press Draw winners to select them sequentially without replacement and see them listed in draw order. FAQ: Q: Can the same person win twice? A: No. Each winner is removed from the pool before the next draw, so the selection is without replacement. The tool also merges identical entries so a name listed twice cannot be drawn twice. Q: Is the draw fair? A: Yes. Every remaining participant has an equal chance on each draw, since a winner is chosen with a uniform random index from the current pool before being removed. Q: What does draw order mean? A: Winners are listed in the order they were selected, which lets you assign first, second, and third prizes. The first name drawn is winner one, the next is winner two, and so on. Q: What if I ask for more winners than participants? A: That is not possible, so the tool shows an error with the number of unique participants available and asks you to reduce the winner count. Q: Are the entries saved anywhere? A: No. The draw runs entirely in your browser and nothing is uploaded or stored. Reloading the page clears your participant list and results. #### Bucket List Item Generator URL: https://geratools.com/random-bucket-list-item-generator Generate bucket list experience ideas across adventure, culture, food, learning, and achievement categories. Pick a category or mix them, choose how many ideas, and get a duplicate-free list, all in your browser. How to use: 1. Choose a category: Pick a theme such as adventure, food, or learning, or leave it on any to draw a mix across all five categories. 2. Set how many ideas: Enter a number from one to ten to control how many distinct ideas the tool returns in each batch. 3. Generate and save: Press generate to get a duplicate-free list, reroll for new ideas, and copy the list when you find ones worth keeping. FAQ: Q: How does it avoid repeating the same idea? A: Within a single batch the tool uses a partial Fisher-Yates shuffle to pick distinct items, so you never see the same idea twice in one list. Rerolling starts a fresh draw that may overlap with earlier batches. Q: What categories are included? A: Five categories are covered — adventure, culture, food, learning, and achievement. Choosing any blends all of them into a single pool so a batch can span several themes at once. Q: Can I get more than ten ideas at once? A: A single batch is capped at ten to keep the list focused and readable. You can press reroll repeatedly to gather more, or copy each batch out before generating the next. Q: Is anything sent to a server? A: No. All the idea lists and the shuffle logic are bundled into the page, so generation happens instantly in your browser with no network requests and nothing is uploaded. Q: Are these ideas realistic for anyone? A: They are written to be concrete but broadly attainable, leaning on experiences rather than expensive purchases. Treat them as a spark and adapt the scale to your own budget, fitness, and time. #### Fantasy Codex Entry Generator URL: https://geratools.com/random-codex-entry-generator Generates short codex and lore entry stubs for fantasy world-building, covering creatures, locations, historical events, and factions. Each entry has a title, type, and a coherent two to three sentence body for game writers and world-builders. How to use: 1. Choose an entry type: Pick creature, location, event, or faction, or leave it on random to draw from all four categories. 2. Generate the entry: Click generate to produce a titled codex stub with a short, coherent lore body you can drop into your world. 3. Copy and refine: Click copy to grab the title and body, then edit names and details to fit your setting before adding it to your wiki. FAQ: Q: What types of entries can it create? A: Four types: creatures with a habitat and an eerie trait, locations with a defining feature, historical events with a cause and a lingering consequence, and factions with a goal and a distinguishing custom. Q: Are the entries internally consistent? A: Yes. Each type uses a dedicated template so the title, category, and body always agree. A creature entry describes a beast, a faction entry describes an organisation, and so on, ready to paste into a world wiki. Q: Can I use these in a published game or novel? A: Yes, treat them as raw material. They are short, evocative stubs meant to be edited and expanded. Swap in your own proper nouns so the lore fits the rest of your setting. Q: How long is each entry? A: Each entry is a title plus a two to three sentence body, the right length for an encyclopedia stub. Generate several and stitch them together for a richer codex section. Q: Is anything sent to a server? A: No. All vocabulary and templates ship with the page and every entry is assembled in your browser. Nothing about your generated lore is uploaded or stored. #### Collective Noun Generator URL: https://geratools.com/random-collective-noun-generator Free collective noun generator that serves the real terms for animal groups — a murder of crows, a parliament of owls, a pod of dolphins — plus a playful invented mode. Great for trivia apps, word games, and educational tools. Runs entirely in your browser. How to use: 1. Choose a mode: Pick real, documented collective nouns or the playful invented mode. 2. Generate: Press the button to draw a random animal and its collective noun. 3. Browse the list: Scroll the full reference table of animals and their group names. FAQ: Q: What is a collective noun? A: A collective noun names a group as a single unit — a flock of birds, a herd of cattle. For animals these are sometimes called terms of venery and many date back to medieval hunting tradition. Q: Are these real terms? A: The real mode uses documented English collective nouns such as a murder of crows, a parliament of owls, and a pod of dolphins. Some have folkloric origins, but all appear in standard references. Q: What does invented mode do? A: Invented mode pairs an animal with a randomly chosen evocative group word, producing fresh coinages like a whisper of foxes. They are not standard but are fun for naming and creative prompts. Q: Why do some animals have several terms? A: English often records more than one collective noun for the same animal — crows can be a murder or a horde, for instance. The generator may show any documented variant. Q: Does anything leave my browser? A: No. Generation runs entirely in your browser with JavaScript, so nothing is sent to a server. #### Compliment Generator URL: https://geratools.com/random-compliment-generator Generates specific, thoughtful compliments across personal, professional, and creative domains by pairing a meaningful opener with a concrete quality. More substantial than generic praise, useful for wellness, social, and team-appreciation contexts. How to use: 1. Choose a domain: Pick personal, professional, or creative depending on who you want to compliment, or leave it on Any. 2. Generate compliments: Click Generate for one compliment, or raise the count to produce a short list to choose from. 3. Make it yours: Copy the compliment that fits best and add a specific detail about the person so it reads as personal rather than generic. FAQ: Q: Why are these compliments longer than 'great job'? A: Specific compliments land harder than generic ones because they show you actually noticed something. Each result names a concrete quality such as breaking a messy problem into clear steps, which feels more sincere than a single adjective like smart or nice. Q: What's the difference between the domains? A: Personal focuses on character and how someone treats others, professional on work skills and reliability, and creative on craft and originality. Pick the domain that matches the relationship, or choose Any to mix them. Q: How do I make a generated compliment feel personal? A: Use it as a frame and add one specific detail. If the compliment is about following through, name the exact promise they kept. That single concrete reference turns a template into something that clearly belongs to them. Q: Can I generate several at once? A: Yes. Raise the count up to ten to produce a short, de-duplicated list, then keep the one or two that fit the person best. Generating a batch is the fastest way to find phrasing that feels right. Q: Is anything stored or sent anywhere? A: No. The openers, qualities, and closers live in the page and compliments are assembled in your browser. Nothing is uploaded and nothing about your session is saved. #### Dystopian Law Generator URL: https://geratools.com/random-dystopia-law-generator Generates fictional dystopian law and regulation text for world-building in speculative fiction. Creates plausible-sounding authoritarian statutes with chilling penalty clauses, ready for writers and game designers building oppressive regimes. How to use: 1. Choose how many laws you want: Enter a number from 1 to 12 to generate a single statute or a short legal code. 2. Generate the laws: Click Generate; each law gets an article number, a mandate or prohibition, and a penalty clause, and the list is sorted by article number. 3. Use them in your world: Drop a law onto a propaganda poster, a courtroom scene, or a regime's charter, and let the penalty clauses do the work of establishing dread. FAQ: Q: What makes the laws feel plausible? A: Each statute follows the dry, bureaucratic register of real legislation — a defined subject, a mandate or prohibition, and a penalty for non-compliance. The horror comes from how reasonable the wording sounds while describing something monstrous. Q: How is each law structured? A: Every law has a numbered article, a body that states who must do or not do what, and a penalty clause that spells out the consequence. The list is sorted by article number so a batch reads like a coherent legal code. Q: Are these laws meant to be taken seriously? A: They are fiction for storytelling and world-building. The point is to characterise an oppressive regime quickly and chillingly, not to propose real policy. Use them as set dressing, plot pressure, or the rules a protagonist must break. Q: How do I build a believable regime from these? A: Generate a short code and look for a through-line: laws about surveillance, about memory, or about assembly each imply a different fear the regime is built around. Pick a theme and keep the laws that reinforce it for a coherent dystopia. Q: Is anything I generate stored or sent away? A: No. The subject, mandate, and penalty tables all live in the page and run in your browser. Nothing is uploaded and nothing about your session is saved. #### Random Emoji Generator URL: https://geratools.com/random-emoji-generator Generate one or many random emoji from the full Unicode emoji set, with category filters for smileys, animals, food, activities, travel, objects, and symbols. Copy the result in one click for games, social posts, and creative prompts. How to use: 1. Pick a category: Choose a category such as animals or food, or leave it on All categories to draw from the whole emoji set. 2. Set how many: Enter how many emoji you want, from one up to fifty, then click Generate to draw a fresh random set. 3. Copy the result: Click Copy to put the space-separated emoji on your clipboard, ready to paste into a chat, post, or document. FAQ: Q: Where do the emoji come from? A: The tool uses a curated set of standard Unicode emoji grouped into the official-style categories such as smileys and emotion, animals and nature, and food and drink. It draws from those bundled lists with no external service. Q: Why does an emoji sometimes look different on my device? A: Emoji are rendered by your operating system and font, so the same Unicode character appears slightly different on Apple, Android, Windows, and other platforms. The character itself is identical; only the artwork changes. Q: Can the same emoji appear more than once? A: Yes. Each slot is drawn independently, so when you request several emoji a repeat is possible, just like rolling the same number twice on dice. Press Generate again for a different mix. Q: Will every emoji display on every device? A: Most will, but very new emoji can show as a box on older systems that have not updated their font. The tool sticks to widely supported characters to keep that rare. Q: Is this private? A: Completely. The emoji lists and the random selection run entirely in your browser, so nothing you generate or copy is ever sent to a server. #### Random Epitaph Generator URL: https://geratools.com/random-epitaph-generator Generates fictional epitaph inscriptions for invented characters in serious, poetic, and humorous tones, with an optional name and dates. Built for horror fiction, Halloween props, tabletop games, and graveyard world-building. How to use: 1. Choose a tone: Pick serious, poetic, or humorous, or leave it on random to draw from all three styles of inscription. 2. Decide on a name and dates: Toggle the name option to add a fictional name and a plausible pair of birth and death years above the text. 3. Generate and copy: Click generate to produce a centred inscription, then copy it to use on a prop, in a story, or in a game. FAQ: Q: What tones are available? A: Three tones: serious solemn dedications, poetic verse-style inscriptions split across short lines, and humorous comic epitaphs. Random mode mixes all three so you can compare styles quickly. Q: Are the names and dates real? A: No. The names are randomly drawn from period-flavoured first and last name lists, and the dates are randomly generated within plausible ranges. They describe no real person, living or dead. Q: What can I use these for? A: They suit Halloween props, haunted-house decor, tabletop RPG graveyards, horror and fantasy fiction, and any scene that needs a believable gravestone. Treat the humorous ones as light entertainment. Q: Why are the poetic epitaphs split into lines? A: Verse epitaphs traditionally break into short rhyming lines, so the tool splits poetic results onto separate lines to match how they would actually be carved on a headstone. Q: Is anything sent to a server? A: No. All the inscription text and name lists ship with the page and every epitaph is assembled in your browser. Nothing about your choices is uploaded or stored. #### Euphemism Generator URL: https://geratools.com/random-euphemism-generator Generate euphemistic phrases for sensitive topics like death, job loss, and money trouble. A free browser tool for copywriters, language teachers demonstrating indirect speech, and humour writing, with curated phrase banks. How to use: 1. Choose a topic: Pick the sensitive subject you want to soften, such as death, losing a job, or being short of money. 2. Generate a phrase: Click Generate to draw a random euphemism from the curated bank for that topic. 3. Reroll and copy: Press Reroll for a different option, then copy the phrase you like best into your writing. FAQ: Q: What is a euphemism? A: A euphemism is a mild or indirect word or phrase substituted for one considered too blunt, harsh, or taboo. For example, saying someone passed away instead of died softens the impact of the statement. Q: Are euphemisms always a good idea? A: Not always. Euphemisms can show tact and kindness, but they can also obscure meaning or sound evasive. In contexts like medical, legal, or safety communication, plain language is usually clearer and more honest. Q: Where do the phrases come from? A: Each topic has a hand-curated bank of common, well-understood euphemisms drawn from everyday English usage. The tool simply picks one at random so you can browse alternatives quickly. Q: Is anything I select sent to a server? A: No. All phrase banks and the selection logic are bundled into the page, so generation happens instantly in your browser and nothing is uploaded. Q: Can I use these in professional writing? A: Yes, where tact is appropriate, such as condolence messages or HR communications. Always weigh whether softening the message helps the reader or simply hides important information. #### Fortune Cookie Generator URL: https://geratools.com/random-fortune-cookie-generator Generates fortune-cookie messages combining gentle wisdom or action advice with six lucky numbers and a lucky word, just like the slip inside a real cookie. Great for apps, games, and any product needing a daily wisdom snippet. How to use: 1. Crack the cookie: Click the button to crack open a virtual fortune cookie and reveal your fortune. 2. Read your fortune and numbers: Read the message, then note your six lucky numbers and the lucky word, generated just like a real cookie slip. 3. Save or share: Copy the full fortune, numbers, and word to share with a friend or paste into your own app. FAQ: Q: Where do the lucky numbers come from? A: The tool generates six distinct numbers between 1 and 69, the same range many lottery slips use, and sorts them low to high. Each crack of the cookie draws a fresh set in your browser using its random number generator. Q: Are these real fortunes or predictions? A: They are entertainment only. The messages are gentle, vague aphorisms in the style of fortune cookies, designed to feel meaningful while applying to almost anyone. Treat them as a fun nudge, not a forecast of actual events. Q: Why is there a lucky word? A: Many modern fortune cookies print a Learn this word line alongside the fortune and numbers. The tool mirrors that format by drawing a pleasant single word, so the output matches the slip you would actually find in a cookie. Q: Will I get the same fortune twice in a row? A: It avoids it. When you crack another cookie, the generator re-rolls if it lands on the fortune you just saw, so consecutive cookies feel different. The numbers and word are regenerated every time regardless. Q: Is anything stored or sent anywhere? A: No. The fortune and word lists live in the page and everything is assembled in your browser. Nothing is uploaded and nothing about your session is saved. #### Headline Pun Generator URL: https://geratools.com/random-headline-pun-generator Generates pun-based news-headline formats on any topic you type, slotting your subject into wordplay-driven headline templates. Built for humor writers, satirists, and social-media creators who want quick, shareable wordplay hooks. How to use: 1. Enter a topic: Type the subject you want the headlines about, such as coffee, crypto, or gardening. Leave it blank to default to weather. 2. Generate headlines: Click Generate to slot your topic into pun-shaped headline templates. Set the count to produce several distinct headlines at once. 3. Pick and polish: Copy the headlines you like and tweak the wording to fit your exact story or post for the best comedic timing. FAQ: Q: How does the pun get made? A: The wordplay lives in the headline templates themselves, which contain phrases like make waves or boiling point. Your topic fills the subject slot, so the joke stays intact whatever subject you choose. The templates are shuffled so a batch shows different puns. Q: Will the same topic always give the same headline? A: No. The tool shuffles its template list each time, so generating again with the same topic produces a fresh set. With a count above one you get several distinct headlines drawn from different templates. Q: Are these real news headlines? A: No. Every headline is a fictional, comedic construction made from templates plus your topic. They are intended as satire and content prompts, not as factual reporting, so do not present them as genuine news. Q: What makes a good topic to enter? A: A short, concrete noun works best, such as coffee, football, or startups. Single words or short phrases slot cleanly into the headline grammar; very long phrases can read awkwardly, so trim them before generating. Q: Is anything stored or sent anywhere? A: No. The templates live in the page and your topic is combined with them in your browser. Nothing you type is uploaded and nothing about your session is saved. #### Random Historical Event Generator URL: https://geratools.com/random-historical-event-generator Generate a random historical event with its year, location, era, and a short description, drawn from a curated database spanning 5,000 years from ancient Egypt to the modern web. Filter by era for trivia and learning. How to use: 1. Choose an era: Leave it on any era, or focus on Ancient, Medieval, Early Modern, or Modern history. 2. Generate an event: Press the button to draw one real historical event at random from the database. 3. Read and continue: Read the year, place, and description, then generate another to keep exploring history. FAQ: Q: Are these real historical events? A: Yes. Every entry is a documented event from the historical record, from the unification of Egypt to the public release of the World Wide Web. None are invented, so they are safe to cite as starting points for further reading. Q: Why do some years have a 'c.' in front of them? A: The abbreviation c. stands for circa, meaning approximately. It marks dates for ancient events that are not known precisely, such as the building of the Great Pyramid, where historians work from estimates rather than exact records. Q: How are the eras defined? A: The tool uses common conventional boundaries: Ancient up to about AD 500, Medieval from 500 to 1450, Early Modern from 1450 to 1800, and Modern from 1800 to the present. These are broad teaching conventions, not strict universal definitions. Q: Can I use this for a quiz or classroom? A: Absolutely. Filter to one era to match a lesson, generate an event, and ask students to place it on a timeline or explain its significance. The short descriptions give just enough context to seed a discussion. Q: Does this require the internet? A: No. The event database is bundled into the page and the random selection runs in your browser, so it works offline once the page has loaded and sends nothing about your activity anywhere. #### Fake Horoscope Generator URL: https://geratools.com/random-horoscope-generator Generates horoscope-style predictions for any zodiac sign or all twelve at once, using appropriately vague astrological language built from a focus area, a prediction, and an advice line. Clearly fictional entertainment for apps and social content. How to use: 1. Choose a sign: Pick one of the twelve zodiac signs, or tick the box to generate a reading for all twelve at once. 2. Generate the reading: Click Generate to build a horoscope from a focus area, a vague prediction, and a line of advice. 3. Share it: Copy a single reading or the full set of twelve to paste into a newsletter, app, or social post. FAQ: Q: Are these real horoscopes? A: No. They are clearly fictional entertainment. The readings are assembled from generic, deliberately vague fragments and carry no astrological meaning. Use them as novelty content, not as guidance for real decisions. Q: How is each reading built? A: Each horoscope combines three parts: a focus area such as love or career, a vague prediction such as a conversation opening a door, and a line of practical-sounding advice. The pieces are picked at random in your browser, so every reading differs. Q: Can I make horoscopes for everyone at once? A: Yes. Tick the Generate all 12 signs box and the tool produces a separate reading for each sign in one click, which is handy for a daily-horoscope column, newsletter, or social roundup. Q: Why do they sound like they could apply to anyone? A: That is intentional and mirrors the so-called Barnum effect that real horoscopes rely on: statements general enough to feel personal to almost everyone. It is part of the fun and a reminder to read them as entertainment. Q: Is anything stored or sent anywhere? A: No. The fragment lists live in the page and readings are assembled in your browser. Nothing is uploaded and nothing about your session is saved. #### Random Icebreaker Generator URL: https://geratools.com/random-icebreaker-generator Free random icebreaker generator with inclusive, work-safe questions for team meetings, remote standups, and community events. Pick a setting and get a fresh, divisive-free prompt every click — runs entirely in your browser. How to use: 1. Choose a setting: Pick a team meeting, remote team, community event, or mixed group. 2. Generate: Click to draw a random icebreaker suited to that setting. 3. Use or copy it: Read it aloud to the group or copy it into your agenda or chat. FAQ: Q: Are the questions safe for work? A: Yes. Every prompt is chosen to be light, inclusive, and free of divisive or personal topics, so it is comfortable to ask in professional and public settings. Q: Do questions change with the setting? A: Yes. Each setting has its own bank — for example, remote-team prompts lean into home-workspace and break habits, while event prompts suit people who may not know each other yet. Q: Will it repeat the same question right away? A: Each click picks at random and avoids repeating the immediately previous prompt where possible, so a run feels varied. Q: Does it send anything to a server? A: No. The prompt bank is bundled with the page and selection runs in your browser using a secure random generator, so it works offline once loaded. Q: How many should I ask in one meeting? A: One well-chosen icebreaker is usually enough to warm up a group. For larger or longer sessions, ask one, let everyone answer briefly, then move on. #### Random Language Generator URL: https://geratools.com/random-language-generator Pick a random natural human language and see its language family, writing script, approximate speaker count, and a notable linguistic feature. Filter by family for linguistics study, trivia, and language-learning inspiration. How to use: 1. Choose a family: Leave it on any family or narrow to one such as Indo-European or Austronesian. 2. Generate a language: Press pick a random language to draw one at random from the dataset. 3. Read the profile: See the family, script, speaker count, and a notable feature, then pick another to keep exploring. FAQ: Q: What does the speaker count include? A: It is an approximate total of both native (first-language) and second-language speakers, rounded for readability. That is why English shows around 1.5 billion: most of those speak it as a second language rather than a mother tongue. Q: What is a language family? A: A language family is a group of languages descended from a common ancestor, like Indo-European which includes English, Hindi, and Russian. The tool groups its languages this way so you can explore how seemingly different tongues are historically related. Q: Why is Basque listed as an isolate? A: A language isolate has no demonstrated relationship to any other living language. Basque, spoken in the Pyrenees, is the classic European example, which is why it sits under other and isolates rather than in a named family. Q: Is the notable feature the only interesting thing about each language? A: No, it is just one memorable hook to spark curiosity, such as a language using clicks or having fifteen grammatical cases. Each language has far more depth, so treat the feature as a starting point for further reading. Q: Does this tool need an internet connection? A: No. The language dataset is bundled into the page and the random pick runs in your browser, so it works offline once loaded and uploads nothing about your choices. #### Leet Speak Generator URL: https://geratools.com/random-leet-speak-generator Converts normal text into leet speak by swapping letters for look-alike numbers and symbols. Choose light, medium, or full intensity to control how heavily your text is 1337-ified. How to use: 1. Enter your text: Type any word or sentence into the input box. Letters that have a leet equivalent are substituted; everything else stays the same. 2. Choose intensity: Pick light for vowels only, medium for the most common substitutions, or full for heavy multi-character symbol swaps. 3. Copy the leet text: The converted 1337 text appears instantly. Copy it for usernames, gamer tags, or chat. FAQ: Q: What is leet speak? A: Leet speak, written as 1337 or l33t, is an internet writing style that replaces letters with numbers and symbols that resemble them. It originated in early hacker, gamer, and bulletin-board culture as a way to write stylishly and sometimes to dodge keyword filters. Q: What do the intensity levels change? A: Light only swaps vowels (a to 4, e to 3, i to 1, o to 0), staying very readable. Medium adds common consonants like s to 5 and t to 7. Full applies heavy multi-character substitutions such as n to backslash-pipe-backslash, producing dense, hard-to-read text. Q: Is leet speak still used today? A: Yes, mostly playfully. It survives in gamer tags, usernames, memes, and nostalgic references to early internet culture. It is no longer an effective way to evade modern content filters, which normalize text before scanning. Q: Can I convert leet text back to normal? A: This tool only converts in one direction, from normal text to leet. Reversing full-intensity leet is ambiguous because some substitutions overlap, so reliable round-tripping is not always possible, especially at higher intensities. Q: Does it change spaces and punctuation? A: No. Only letters that have a defined leet substitution are changed. Spaces, punctuation, and any character without a mapping are passed through unchanged so the structure of your text stays intact. #### Fictional Legend Generator URL: https://geratools.com/random-legend-generator Creates short fictional legend and myth summaries with a full origin structure: a central figure, a deed against an antagonist, an outcome, and a closing moral lesson. Built to enrich fantasy world lore and tabletop campaigns. How to use: 1. Generate a legend: Click generate to produce a titled legend with a figure, a deed, an outcome, and a moral lesson. 2. Read the structure: Each legend follows the classic origin-myth shape, so you can lift the framework even if you change the details. 3. Copy and adapt: Click copy to grab the title and body, then rename the figures and antagonist to fit your setting. FAQ: Q: What structure do the legends follow? A: Each legend names a central figure, sets a mythic time, pits the figure against an antagonist, describes the costly deed they undertake, gives the outcome, and ends with a moral. It mirrors how real folklore is built. Q: Are the legends complete stories? A: They are concise summaries, the kind of paragraph that might open a chapter of folklore. They give you a complete arc to expand into a full tale or a campaign hook. Q: Can I use these in a game or novel? A: Yes. Treat them as seeds. Swap in your own names, places, and gods so the legend fits the surrounding lore, then expand the deed and outcome into scenes. Q: Why does each legend end with a moral? A: Real myths and legends almost always carry a lesson, so the generator closes every tale with a maxim. It anchors the story's meaning and gives storytellers a theme to build around. Q: Is anything sent to a server? A: No. All the vocabulary and templates ship with the page and every legend is assembled in your browser. Nothing about your generated text is uploaded or stored. #### Meal Plan Generator URL: https://geratools.com/random-meal-plan-generator Generate a weekly meal plan with breakfast, lunch, dinner, and snacks. Filter by diet (vegetarian, vegan, keto, high-protein) and a daily calorie target that is split across meals. Ideal for nutrition app demos and prototypes. How to use: 1. Choose a dietary preference: Select balanced, vegetarian, vegan, keto, or high-protein. Each pulls meal ideas from a matching food bank. 2. Set a daily calorie target: Enter target calories per day. The tool splits them across breakfast, lunch, dinner, and a snack and rounds each to the nearest ten. 3. Regenerate and copy: Click Regenerate for new meal picks, then copy the full week as plain text for your demo or seed data. FAQ: Q: Are the calorie numbers nutritionally precise? A: No. Calories are an even split of your daily target across meals using fixed proportions, not measured values for each dish. Treat the figures as illustrative placeholders for demos, not a real dietary plan. Q: How is the daily target divided between meals? A: The generator uses a fixed split of roughly 25 percent breakfast, 35 percent lunch, 30 percent dinner, and 10 percent snack, then rounds each meal to the nearest ten calories so the displayed numbers stay tidy. Q: Do the diet filters change the food choices? A: Yes. Each diet has its own bank of breakfasts, lunches, dinners, and snacks, so a vegan plan never suggests meat and a keto plan favours low-carb, higher-fat dishes. Q: Why do reruns sometimes match? A: The tool is seeded for reproducibility, so the same seed and settings produce the same plan. Regenerate advances the seed to give you fresh meal combinations. Q: Can I use this for a real diet? A: It is meant for app demos and prototypes, not personalised nutrition. Consult a registered dietitian for an actual plan, especially if you have medical or dietary conditions. #### Mission Statement Generator URL: https://geratools.com/random-mission-statement-generator Generate company mission statement drafts for for-profit, nonprofit, startup, and enterprise organizations. Follows the standard verb-plus-audience-plus-impact structure to turn your purpose into a clear, paste-ready statement. How to use: 1. Pick your org type: Choose for-profit, nonprofit, startup, or enterprise so the tone and verbs fit your organization. 2. Add your purpose: Enter who you serve and the impact you want to create, then generate a structured statement. 3. Refine and adopt: Generate a few variations, copy the one that fits best, and edit it to sound like your real organization. FAQ: Q: What is the difference between a mission and a vision statement? A: A mission statement describes what you do now and for whom, while a vision statement describes the future world you are working toward. Mission is about present purpose and activity, and vision is about long-term aspiration. Most organizations write both. Q: How long should a mission statement be? A: One or two sentences is ideal. The strongest mission statements fit in a single memorable line that anyone in the organization can recall and repeat. If it takes a paragraph to explain your mission, it is probably a description, not a mission. Q: Is the generated statement final? A: No. The tool produces a structured draft from your inputs and word banks. Treat it as a starting point, then edit the wording until it sounds authentic to your organization and reflects what you genuinely do. Q: What should a good mission statement include? A: A clear action verb, a defined audience or beneficiary, and the impact or change you create. Avoid jargon and buzzwords that could apply to any company. Specificity about who you serve and what changes for them is what makes a mission statement meaningful. Q: Does this tool send my inputs anywhere? A: No. The word banks and assembly logic are bundled into the page, so each statement is generated in your browser. Nothing you enter is uploaded. #### Random Monster Generator URL: https://geratools.com/random-monster-generator Generates unique monster summaries with a name, creature type, challenge rating, AC, HP, a special ability, habitat, and a lore snippet. Great for home-brew encounters and quick dungeon master prep. How to use: 1. Generate a monster: Tap the button to roll a name, type, challenge rating, defensive stats, ability, habitat, and lore. 2. Read the stat summary: Review the CR, AC, and HP alongside the special ability to gauge how the creature plays in combat. 3. Reroll or copy: Regenerate for a new creature, then copy the summary into your bestiary or encounter notes. FAQ: Q: Are the stats ready to drop into combat? A: They give you a usable skeleton, AC, HP, and CR that scale together for plausibility, plus one signature ability. You will still add attacks and ability scores, but the summary is enough to improvise an encounter. Q: How do the AC and HP relate to the challenge rating? A: The generator scales hit points and armour class loosely with the rolled challenge rating, so a higher-CR creature is tougher. Always tune the numbers to your party's level before running it. Q: How varied are the monsters? A: Names, types, ratings, abilities, habitats, and lore are each chosen independently, giving thousands of combinations. The randomised AC and HP add further variety even on repeats. Q: Can I use these in published work? A: Yes. The creatures are original building blocks you can rename, restat, and expand for personal or commercial campaigns and adventures. Q: Is anything sent to a server? A: No. All the components are bundled with the page and combined in your browser. Nothing about your monsters is uploaded or stored. #### NGO & Nonprofit Name Generator URL: https://geratools.com/random-ngo-name-generator Generates nonprofit and NGO names using cause-related vocabulary, geographic identifiers, and mission-statement naming patterns. Covers environment, health, education, and human rights. How to use: 1. Choose a cause: Pick environment, health, education, or human rights so the vocabulary matches your sector. 2. Pick a naming style: Choose cause-plus-org-word, geographic, mission-statement, or mixed to draw from all three nonprofit patterns. 3. Generate and copy: Set a batch size, click generate, and copy any name into your brief, pitch deck, or document. FAQ: Q: What naming styles does it use? A: Three real nonprofit patterns: cause plus an org word like Clean Water Alliance, geographic like Global Forest Trust, and mission statements like Hope for Children. Mixed mode blends all three by sector. Q: Are these real charities? A: No. Names are randomly assembled from curated lists for inspiration, demos, and fiction. Any match with an existing nonprofit is coincidental, so verify before adopting one. Q: Why does choosing a cause matter? A: Each cause has its own vocabulary — clean water and wildlife for environment, literacy and scholars for education. Selecting a cause keeps the generated names relevant and credible to your sector. Q: Can I register a generated name as a charity? A: Treat it as a starting point. Before registering you must check the charity register in your country, a trademark database, and domain availability, since many cause words are heavily used. Q: Is my data sent anywhere? A: No. All vocabulary is bundled with the page and names are assembled in your browser. Nothing about your choices is uploaded or stored. #### Gaussian Random Number Generator URL: https://geratools.com/random-number-generator-gaussian Generate random numbers from a normal (Gaussian) distribution with a configurable mean and standard deviation using the Box-Muller transform. Includes sample statistics for simulations and testing. How to use: 1. Set the parameters: Enter the desired mean and a positive standard deviation that describe the normal distribution you want to sample from. 2. Choose a sample size: Type how many numbers to generate, from 1 up to 1000, then press Generate. 3. Review the output: Read the generated samples plus the sample mean, sample standard deviation, and min/max to verify the distribution. FAQ: Q: How are the numbers generated? A: The tool uses the Box-Muller transform, which converts two independent uniform random values into a standard normal value, then scales and shifts it by your standard deviation and mean. Q: Why does the sample mean not exactly equal my chosen mean? A: Random samples fluctuate around the true mean. With small sample sizes the sample mean and standard deviation can differ noticeably; they converge toward your inputs as the sample size grows. Q: What values are allowed? A: The mean can be any real number, the standard deviation must be greater than zero, and the count must be a whole number between 1 and 1000. Invalid inputs are rejected with a message. Q: What is a normal distribution used for? A: The normal or Gaussian distribution models many natural quantities such as measurement error, heights, and test scores. These samples are useful for Monte Carlo simulations, statistics teaching, and seeding test data. Q: Are the numbers cryptographically secure? A: No. They come from the browser's Math.random generator, which is fine for simulations and testing but should not be used for cryptography or anything security-sensitive. #### Onomatopoeia Generator URL: https://geratools.com/random-onomatopoeia-generator Generate lists of onomatopoeia by category, covering animal sounds, machine sounds, impact sounds, weather, and human noises. A free browser tool for creative writing, comics, and language education. How to use: 1. Pick a category: Choose the kind of sound you need, such as animal, machine, impact, weather, or human. 2. Set how many words: Enter how many distinct words you want, up to the number available in that category. 3. Generate and copy: Click Generate to shuffle a unique list, reroll for a new draw, and copy the words you want. FAQ: Q: What is onomatopoeia? A: Onomatopoeia is the formation of a word from the sound associated with what it names, such as buzz, splash, or clang. Reading the word aloud roughly imitates the real sound it describes. Q: How are the words grouped? A: Words are organised into categories by the kind of sound they imitate: animal sounds like meow and moo, mechanical sounds like beep and whir, impacts like bang and thud, weather like patter, and human noises like achoo. Q: Will I get duplicates? A: No. The tool shuffles the category list and takes the number you requested without repeating, so each generated set contains distinct words up to the size of that category. Q: Can the same word appear in two categories? A: Yes. A few words like buzz fit more than one category, for example both an insect and an electrical device, so they appear in each relevant list. Q: Does this use the internet? A: No. Every word list is bundled into the page and shuffled in your browser, so it works offline and uploads nothing. #### Portmanteau Word Generator URL: https://geratools.com/random-portmanteau-generator Free portmanteau generator that blends two words into new coinages (like brunch or smog) using several real blending strategies — head plus tail, overlap fusion, and syllable swap. Great for product naming, brand ideas, and creative writing. Runs entirely in your browser. How to use: 1. Enter two words: Type a first and second word you want to blend together. 2. Generate blends: The tool combines them with several strategies, producing multiple candidate portmanteaus. 3. Pick and copy: Choose the blend you like best and copy it for use as a name or coinage. FAQ: Q: What is a portmanteau? A: A portmanteau is a word made by blending the sounds and meanings of two others, such as breakfast plus lunch giving brunch, or smoke plus fog giving smog. The term itself was popularized by Lewis Carroll. Q: How does the generator blend words? A: It applies several strategies: taking the head of the first word and the tail of the second, fusing them at a shared overlapping letter, and swapping at the vowel boundary. Each strategy yields a different candidate. Q: Why do I get several results? A: Different blend points produce different-sounding words, and which one reads best is subjective. Showing multiple candidates lets you pick the most pronounceable or brandable option. Q: Are the blends real words? A: No — they are newly coined blends, which is the point. Always check a candidate for unintended meanings or existing trademarks before using it as a brand name. Q: Does anything get uploaded? A: No. All blending runs entirely in your browser with JavaScript, so the words you enter never leave your device. #### Potion Generator URL: https://geratools.com/random-potion-generator Creates fantasy potion names, colors, smells, effects, and quirky side effects for tabletop RPG settings. Useful for dungeon masters stocking shops, building loot tables, and rewarding encounters with flavour. How to use: 1. Brew a potion: Tap the button to mix a name, colour, smell, effect, and side effect into one mysterious potion. 2. Read the description: Review how it looks, smells, what it does, and the quirky catch so you can describe it to players. 3. Reroll or copy: Regenerate for a different brew, then copy the description into your shop list or loot table. FAQ: Q: Why do potions have a side effect? A: A small, often harmless side effect adds flavour and risk, making players hesitate before drinking an unidentified potion. It turns a simple buff into a memorable moment at the table. Q: Are the effects usable in D&D? A: Yes. Effects use familiar conventions like healing dice, darkvision, and saving throws, so they slot into 5e and most fantasy systems. Adjust the numbers to fit the power level of your party. Q: How many potions can it make? A: Names, colours, smells, effects, and side effects are each chosen independently, producing thousands of combinations, so you can stock an entire apothecary without obvious repeats. Q: Can players identify the potion first? A: That is up to you. The colour and smell make great clues for an Arcana or Medicine check, letting players guess the effect before they risk a sip. Q: Is anything sent to a server? A: No. All potion components are bundled with the page and combined in your browser. Nothing about your brews is uploaded or stored. #### Fantasy Prophecy Generator URL: https://geratools.com/random-prophecy-generator Generates vague, poetic prophecy texts in five lines of archaic language and symbolic imagery, following the conventions of chosen-one prophecies in fantasy literature and tabletop RPGs. Built for game masters and authors. How to use: 1. Generate a prophecy: Click the button to produce a five-line prophecy with an omen, a condition, the chosen one, a trial, and a warning. 2. Read it aloud: The lines are written in archaic, symbolic verse meant to be spoken by an oracle or carved on an ancient stone. 3. Copy and weave it in: Click copy to grab all five lines, then adjust the imagery to foreshadow events in your own story. FAQ: Q: What structure does each prophecy follow? A: Five lines, each with a role: an opening omen, a worsening condition, the arrival of the chosen one, the trial they must endure, and a closing warning. Together they read as a single coherent foretelling. Q: Why are the prophecies so vague? A: Real fantasy prophecies stay deliberately ambiguous so they can be reinterpreted as a plot unfolds. The generator uses symbolic imagery and open phrasing so you can bend the meaning to fit your story's twists. Q: Can I use these for a tabletop campaign? A: Yes. They make excellent campaign hooks. Drop one on the players early, then decide later which interpretation comes true. The built-in warning line is perfect for setting up a twist. Q: Are the prophecies different every time? A: Each of the five lines is drawn independently from its own pool, so the combinations vary widely. Generate several and pick the one whose imagery best matches the threat looming over your world. Q: Is anything sent to a server? A: No. All the verse fragments ship with the page and every prophecy is assembled in your browser. Nothing about your generated text is uploaded or stored. #### D&D Quest Generator URL: https://geratools.com/random-quest-generator Generates D&D quest hooks with an inciting incident, location, antagonist, stakes, and reward type. Instantly usable adventure seeds for dungeon masters at any experience level who need a session on short notice. How to use: 1. Generate a quest: Tap the button to assemble a hook, location, antagonist, stakes, and reward into a complete adventure seed. 2. Read the five parts: Review each element to understand who wants what, where it happens, and why it matters to the party. 3. Reroll or copy: Regenerate until a seed clicks, then copy it into your session prep notes to flesh out fully. FAQ: Q: Is this a full adventure or just a seed? A: It is a seed. The five parts give you a strong skeleton, the who, where, and why, but you still flesh out encounters, NPCs, and maps. That is by design, so it fits any setting and level. Q: How do the five parts fit together? A: The hook draws the party in, the location is where the trail leads, the antagonist drives the conflict, the stakes raise the urgency, and the reward gives the players a reason to commit. Together they form a complete plot beat. Q: How many quests can it make? A: Each part is chosen independently from its own list, producing tens of thousands of combinations, so you can prep for months without an obvious repeat. Q: Can I use it for systems other than D&D? A: Yes. The seeds are system-agnostic fantasy plots. They work for Pathfinder, Old-School Renaissance games, and most fantasy RPGs with light tweaking. Q: Is anything stored or sent anywhere? A: No. All quest components are bundled with the page and combined in your browser. Nothing about your quests is uploaded or saved. #### Security Question Generator URL: https://geratools.com/random-security-question-generator Generate security challenge question and answer pairs in the format used by legacy authentication systems. Useful for testing account recovery flows, seeding QA fixtures, and building security Q&A demos. How to use: 1. Pick how many pairs: Choose how many question-and-answer pairs you need for your test or demo. 2. Generate: Click Generate to produce randomly selected questions each with a plausible sample answer. 3. Copy and reuse: Copy the JSON or plain-text block straight into your test fixtures or recovery-flow mockups. FAQ: Q: Should I use these questions for real accounts? A: No. Knowledge-based authentication is widely considered weak because answers are often public or guessable. These pairs are for testing and demos only, not production security. Q: Are the answers real? A: No. The answers are randomly chosen sample values so the pairs are self-consistent for testing. They never describe a real person. Q: Why do auth systems still use security questions? A: They are cheap to implement and require no extra hardware, so legacy and recovery flows still use them. Modern systems prefer email or SMS one-time codes and passkeys instead. Q: Can I get the output as JSON? A: Yes. The tool shows both a human-readable list and a JSON array you can paste directly into test fixtures or seed scripts. #### Simile Generator URL: https://geratools.com/random-simile-generator Generate vivid similes using as X as Y and subject-verb-like-a patterns that pair qualities with unexpected comparators. A free browser tool for creative writing, poetry, and rhetoric education. How to use: 1. Pick a pattern: Choose the as quality as comparator form or the subject verb like a form depending on the rhythm you want. 2. Generate: Click Generate to combine a descriptive quality or action with an unexpected comparator into a complete simile. 3. Reroll and copy: Reroll until a comparison surprises you, then copy it and adapt the wording to your sentence. FAQ: Q: What is a simile? A: A simile is a figure of speech that compares two different things using like or as, such as as cold as a banker's smile. The explicit comparison word is what distinguishes a simile from a metaphor. Q: How is a simile different from a metaphor? A: A simile keeps the two things separate and links them with like or as, while a metaphor states that one thing is the other. As brave as a lion is a simile; he is a lion in battle is a metaphor. Q: What are the two patterns? A: The first pattern is as quality as comparator, for example as quiet as a held breath. The second is subject verb like a comparator, for example she moved like a leaf caught in a current. Q: Will the comparisons always make literal sense? A: Not always, and that is intentional. Fresh similes often pair things that are not obviously related, which is what makes them memorable. Keep the ones that create a striking image and reroll the rest. Q: Is anything uploaded? A: No. The quality and comparator lists are bundled into the page and combined locally, so generation is instant and private. #### Spaceship Class Name Generator URL: https://geratools.com/random-spaceship-class-generator Generates spaceship class designations (destroyer, frigate, dreadnought, hauler, scout) with fictional technical names. Useful for sci-fi world-building and military fiction. How to use: 1. Choose a ship role: Pick military, civilian, or any to set the hull types and class words — warships versus haulers and scouts. 2. Generate a class: Click to produce a class designation in the X-class Type form, plus a hull number and the ship's role. 3. Copy the result: Use copy to grab the designation and hull number together, then paste into your ship roster or fleet document. FAQ: Q: What format are the names in? A: Each result follows the real naval convention of a class name plus a hull type, such as Valiant-class Destroyer or Horizon-class Hauler. A pennant-style hull number like NV-4821 is included for flavour. Q: What is the difference between military and civilian? A: Military mode uses warship hulls like destroyer, frigate, and dreadnought with martial class words. Civilian mode uses hulls like hauler, freighter, and scout with explorer-style class words. Any mixes both, favouring military. Q: Why is there a hull number? A: Real and fictional navies assign each vessel a hull or pennant number, so the generator adds a prefix and a random number to make the ship feel like part of a registered fleet. Q: Can I use these in a game or novel? A: Yes. Class words and hull types are generic naval and sci-fi terms not tied to any franchise, so they are safe for original work. A quick search avoids overlap with famous ship classes. Q: Is my data sent anywhere? A: No. All word and hull lists are bundled with the page and every ship is generated in your browser. Nothing is uploaded or stored. #### Magic Spell Generator URL: https://geratools.com/random-spell-generator Generates fantasy spell names, schools of magic, levels, effects, casting times, ranges, and components for tabletop RPGs. Perfect for D&D dungeon masters, home-brewers, and fantasy writers needing fresh magic. How to use: 1. Generate a spell: Tap the button to assemble a name, school, level, effect, and casting details into a full spell. 2. Read the spell block: Review the level and school, casting time, range, components, and mechanical effect like a real stat block. 3. Reroll or copy: Regenerate until you find a fit, then copy the spell block into your campaign notes or character sheet. FAQ: Q: Are the effects balanced for D&D 5e? A: The effects use familiar 5e conventions like damage dice, saving throws, and AC bonuses, so they read like real spells. Always sanity-check the level versus the effect for your table before using one in play. Q: What do the schools of magic mean? A: Each spell is tagged with one of the eight classic schools, such as Evocation for raw energy or Illusion for deception. The school helps you decide which classes might learn it and how it fits your world. Q: How varied are the results? A: Names, levels, schools, effects, components, casting times, and ranges are each chosen independently, giving thousands of combinations so repeats are rare. Q: Can I use these in my published adventure? A: Yes. The generated spells are original building blocks you can rename, rebalance, and expand freely for personal or commercial campaigns. Q: Is anything stored or sent anywhere? A: No. All spell components are bundled with the page and combined locally in your browser. Nothing is uploaded or saved between visits. #### Stoic Philosophy Quote Generator URL: https://geratools.com/random-stoic-quote-generator Free Stoic quote generator. Get random, sourced quotes from the great Stoic philosophers — Marcus Aurelius, Epictetus and Seneca — filterable by author and copyable in one click. Perfect for journaling, meditation and reflection. Runs in your browser. How to use: 1. Choose a philosopher: Leave it open to any Stoic, or focus on Marcus Aurelius, Epictetus or Seneca to hear from one voice. 2. Generate a quote: Press New quote to draw a random, sourced quote; it won't repeat the one you just read. 3. Copy with attribution: Copy quote grabs the text along with the author and the primary work it comes from. FAQ: Q: Who are the Stoics quoted here? A: The three central figures of Roman Stoicism — Marcus Aurelius (a Roman emperor), Epictetus (a former slave turned teacher), and Seneca (a statesman and writer). Their works are still the most-read sources of Stoic thought. Q: Are the source works shown? A: Yes. Each quote is attributed to its author and primary work, such as Marcus Aurelius's Meditations, Epictetus's Discourses, or Seneca's Letters to Lucilius, so you can trace it back. Q: What is Stoicism, briefly? A: Stoicism is an ancient Greek and Roman philosophy that teaches focusing on what is within your control, accepting what is not, and cultivating virtue and reason as the path to a tranquil, meaningful life. Q: Is this useful for journaling or meditation? A: Very. Many people use a single Stoic quote as a daily prompt — reading it in the morning and reflecting on how it applies, or writing a short journal response in the evening. Q: Does the tool need an internet connection? A: No. The full quote list ships with the page and selection happens locally, so it works offline and sends nothing to any server. #### Supernatural Ability Generator URL: https://geratools.com/random-supernatural-power-generator Generates supernatural ability descriptions for witches, psychics, demigods, and paranormal characters. Each ability comes with a trigger condition and a built-in limitation so the power stays balanced, dramatic, and story-ready rather than overpowered. How to use: 1. Choose how many to generate: Enter a number from 1 to 10 depending on whether you want a single power or a shortlist to choose from. 2. Generate the abilities: Click Generate and each result pairs an ability with a trigger condition and a cost so it is balanced rather than limitless. 3. Assign it to a character: Pick the ability that fits your character, then lean into its trigger and limitation as sources of tension in your story. FAQ: Q: Why does every ability include a trigger and a limitation? A: An unlimited power is dull because nothing is ever at stake. The trigger condition controls when the ability works and the limitation sets its cost, so the power creates drama. The most interesting scenes usually happen at the edges of those rules. Q: Are these abilities meant for fiction or for games? A: Both. Urban fantasy and paranormal writers can hand an ability to a character, and tabletop or LARP designers can use the trigger and limitation as the basis for a real game mechanic. Just translate the cost into your system's terms. Q: How do I make a power feel unique to a character? A: Tie the trigger and limitation to who the character is. A power that only works when you are afraid means something very different on a coward than on a daredevil. The same ability becomes distinct once it reflects personality and backstory. Q: Can I combine parts from different results? A: Yes. Generate a batch, then mix an ability you like with a trigger and limitation from other rolls until the combination feels right. The three parts are independent, so any mix is valid. Q: Is anything I generate stored or uploaded? A: No. The ability, trigger, and limitation tables all live in the page and the descriptions are assembled in your browser. Nothing is sent anywhere and nothing about your session is saved. #### Fantasy Tavern Menu Generator URL: https://geratools.com/random-tavern-menu-generator Free fantasy tavern menu generator. Creates thematic food and drink items with evocative names, gold-piece prices and short descriptions for any RPG inn. Add instant flavor to your D&D or tabletop session, all in your browser. How to use: 1. Set the menu size: Choose how many food dishes and how many drinks you want the tavern to serve. The generator mixes adjectives, ingredients and dish styles for each line. 2. Generate the menu: Click Generate to roll a fresh set of named items. Each item shows a name, a one-line description and a price in copper, silver or gold pieces. 3. Copy or re-roll: Copy the full menu as plain text to drop into your notes or VTT, or re-roll until the inn feels right for your scene. FAQ: Q: How are the prices decided? A: Each item is priced using a small fantasy economy where common fare costs a few copper, hearty meals run into silver, and rare delicacies or strong spirits reach gold. Prices are shown in the standard cp, sp and gp coin notation. Q: Can I control how many items appear? A: Yes. You set the number of dishes and the number of drinks independently, from a single item up to a dozen each, so you can make a humble roadside inn or a sprawling city tavern. Q: Are the names ever repeated in one menu? A: The generator draws fresh combinations on each roll, so duplicates within a single menu are rare. If you see two similar lines, simply re-generate and the wordlists will recombine differently. Q: Is this tied to any specific game system? A: No. The output is system-neutral flavor text. The coin notation matches common fantasy conventions used by D&D and Pathfinder, but the names and descriptions work in any tabletop or fiction setting. Q: Does it send my menus anywhere? A: No. Everything is generated locally in your browser from built-in wordlists. Nothing is uploaded, so you can use it offline and your menus stay private. #### Team Challenge Generator URL: https://geratools.com/random-team-challenge-generator Free team challenge generator with virtual, in-person, and hybrid team-building ideas. Each challenge comes with an estimated duration and required materials, so HR and team leads can plan in seconds — all in your browser. How to use: 1. Pick a format: Choose virtual, in-person, or hybrid to match how your team will meet. 2. Generate a challenge: Click to draw a random activity suited to that format. 3. Plan it: Use the listed duration and materials to schedule and prep, then copy the details. FAQ: Q: Do the challenges include time and materials? A: Yes. Every challenge shows an estimated duration and the materials or tools you need, so you can judge fit and prepare before the session. Q: What is the difference between the three formats? A: Virtual challenges work over a video call, in-person ones need a shared physical space, and hybrid ones are designed so remote and in-room people play together fairly. Q: Will I keep getting the same idea? A: Each click picks at random and avoids repeating the previous challenge where possible, so you can browse several before deciding. Q: Is this only for big companies? A: No. The challenges scale to small teams and large groups alike; durations are estimates you can adjust for your headcount. Q: Does it use the internet to fetch ideas? A: No. The challenge bank is bundled with the page and selection runs locally in your browser, so it works offline once loaded. #### Treasure Hoard Generator URL: https://geratools.com/random-treasure-generator Free RPG treasure hoard generator. Rolls coins, gems, art objects and magic-item hints scaled by challenge rating, following D&D-style loot distribution tables. Build balanced rewards for any encounter in your browser. How to use: 1. Pick a challenge tier: Choose the challenge-rating band of the encounter (CR 0–4, 5–10, 11–16 or 17+). The tier sets how much coin and how valuable the gems, art and magic become. 2. Roll the hoard: Click Generate to roll coins for each metal, then roll for gems, art objects and a chance of magic-item hints, using tiered value tables. 3. Copy the result: Copy the formatted hoard as plain text into your encounter notes, or re-roll until the reward fits the moment. FAQ: Q: Which tables does this follow? A: It mirrors the structure of D&D 5e treasure-hoard tables: coins scale by tier across copper, silver, gold and platinum; gems and art objects come from value bands (10 gp up to 7,500 gp); and higher tiers add a growing chance of magic-item hints. Q: How do challenge ratings affect the loot? A: Higher tiers multiply coin amounts and shift gems and art into more valuable bands. A CR 0–4 hoard might hold a handful of silver and a 10 gp gem, while a CR 17+ hoard can hold thousands of platinum and a 5,000 gp art object. Q: Does it give actual magic items? A: It gives magic-item hints by rarity rather than naming specific items, so you stay free to choose the exact item that suits your campaign. The chance and rarity of a hint increase with the challenge tier. Q: Can I re-roll if I do not like the result? A: Yes. Every click rolls a fresh hoard. Treasure is random by design, so re-roll as many times as you like until the gold, gems and magic feel right for your encounter. Q: Is anything sent to a server? A: No. All rolls happen locally in your browser using built-in tables and a random number generator. Nothing is uploaded, so the tool works offline and your loot stays private. #### Random Trivia Question Generator URL: https://geratools.com/random-trivia-question-generator Free random trivia question generator covering history, science, pop culture, geography, and sports, each with a reveal-on-demand answer. Perfect for quiz nights, classroom warm-ups, and apps — runs entirely in your browser. How to use: 1. Pick a category: Choose a topic such as history or science, or leave it on Any. 2. Generate a question: Click to draw a random trivia question from that category. 3. Reveal the answer: Click Reveal answer when ready, or copy the question and answer together. FAQ: Q: Are answers hidden until I want them? A: Yes. Each question shows on its own first, and the answer stays hidden behind a Reveal button so you can use it as a quiz prompt before checking. Q: What categories are covered? A: History, science, pop culture, geography, and sports. Choosing Any picks a random category for each question, giving you a varied mixed round. Q: Are the answers accurate? A: Answers reflect well-established facts. A few questions note genuine debate — for example the world's longest river — so you can mention the nuance during a quiz. Q: Can I use these for a quiz night or app? A: Yes. The questions are general-knowledge style and suit pub quizzes, classroom warm-ups, and casual apps. Copy the question and answer to drop into your own materials. Q: Does it fetch questions from the internet? A: No. The question bank is bundled with the page and selection runs locally in your browser, so it works offline once loaded. #### Random Word Generator URL: https://geratools.com/random-word-generator Generate random English words filtered by part of speech (noun, verb, adjective, adverb) and difficulty level from easy to advanced. Useful for word games, writing prompts, vocabulary practice, and brainstorming. How to use: 1. Set your filters: Choose a part of speech and a difficulty level, or leave either on any for a wider draw. 2. Choose how many words: Use the slider to draw between one and ten distinct words in a single pass. 3. Generate and copy: Press generate to draw words tagged by type and difficulty, then reroll or copy the list. FAQ: Q: What do the difficulty levels mean? A: Difficulty is a rough guide to how common a word is. Easy words are everyday vocabulary like apple and run, medium words are less frequent like lantern and cultivate, and hard words are advanced or literary like ineffable and acquiesce. Q: Can I get only one part of speech? A: Yes. Use the part-of-speech dropdown to limit the draw to nouns, verbs, adjectives, or adverbs, which is handy for grammar exercises or fitting words into a specific slot in a sentence or game. Q: Will I ever get the same word twice in one draw? A: No. Within a single generation the tool samples without replacement, so every word in the list is distinct. Across separate draws words can repeat because each pass starts from the full filtered pool again. Q: What happens if no words match my filters? A: If a combination has no matching words the tool shows a short message asking you to widen the filters, rather than returning an empty result. Loosening either the part of speech or the difficulty will fix it. Q: Does this need an internet connection? A: No. The word lists are bundled into the page and the random selection runs in your browser, so the tool works offline once loaded and uploads nothing about the words you generate. #### Agile Retrospective Question Generator URL: https://geratools.com/retrospective-question-generator Free agile retrospective question generator with went-well, improve, and action prompts plus full retro formats — Starfish, 4Ls, and Mad/Sad/Glad. Built for scrum masters and team leads who want fresh prompts every sprint, all in your browser. How to use: 1. Choose a mode: Pick question focus for targeted prompts, or retro format for a full framework. 2. Configure it: Select a focus and how many questions, or choose Starfish, 4Ls, or Mad/Sad/Glad. 3. Generate: Click Generate to draw fresh prompts, then copy them into your retro board. FAQ: Q: What is the difference between focus mode and format mode? A: Focus mode draws a random set of prompts about one theme — what went well, what to improve, or actions. Format mode returns the complete prompt set for a named retrospective framework so you can run the whole exercise. Q: Which retro formats are included? A: Starfish (Keep, More, Less, Start, Stop), 4Ls (Liked, Learned, Lacked, Longed for), and Mad/Sad/Glad. Each returns the canonical prompts for that framework. Q: Will I get repeated questions? A: In focus mode each generated set is shuffled and has no internal duplicates. Generate again for a fresh random selection so retros do not feel stale week after week. Q: Is this only for software teams? A: No. The prompts are framework-based and work for any team that runs retrospectives — product, design, marketing, or operations. Q: Does it store our retro answers? A: No. The tool only generates prompts locally in your browser. Your team's discussion and answers stay wherever you record them. #### RPG Character Backstory Generator URL: https://geratools.com/rpg-backstory-generator Free RPG backstory generator. Rolls birthplace, formative event, motivation, flaw and bond for fantasy races and archetypes, then weaves them into a short origin paragraph for your tabletop character, all in your browser. How to use: 1. Choose race and archetype: Pick a fantasy race and a character archetype, or leave them on random. These shape the birthplace and the tone of the backstory elements. 2. Generate the backstory: Click Generate to roll a birthplace, formative event, driving motivation, flaw and bond, then read the woven origin paragraph below. 3. Copy or re-roll: Copy the result into your character sheet or notes, or re-roll individual ideas until the story clicks. FAQ: Q: Which races and archetypes are covered? A: Common fantasy races such as human, elf, dwarf, halfling, orc, tiefling and dragonborn, and archetypes like fighter, rogue, wizard, cleric, ranger, bard and warlock. You can also leave either field on random to be surprised. Q: What does the backstory include? A: Each roll produces five building blocks: a birthplace, a formative event from the character's past, a driving motivation, a personal flaw and a meaningful bond. They are then combined into a short narrative paragraph you can edit freely. Q: Is the paragraph ready to use as written? A: It is a strong starting point rather than a finished biography. The elements are deliberately open-ended so you can rename people, add detail and tie the bond to your campaign before play. Q: Can I keep re-rolling for ideas? A: Yes. Every click rerolls all five elements and rewrites the paragraph, so you can generate dozens of options quickly and stop when one resonates with the character you have in mind. Q: Does it send my characters anywhere? A: No. Everything is generated locally in your browser from built-in idea lists. Nothing is transmitted, so it works offline and your characters stay private. #### RPG Personality Traits Generator URL: https://geratools.com/rpg-personality-traits-generator Free RPG personality generator. Rolls D&D-style personality traits, ideals, bonds and flaws for character creation, with the ideal keyed to your chosen alignment. Flesh out any tabletop character in your browser. How to use: 1. Pick an alignment: Choose your character's alignment, or leave it random. The alignment determines which thematic ideal is offered, matching D&D's trait, ideal, bond and flaw structure. 2. Generate the set: Click Generate to roll two personality traits, one ideal, one bond and one flaw. These are the four standard fields used on a D&D character sheet. 3. Copy the result: Copy the formatted block into your character sheet, or re-roll until the combination fits the character you are building. FAQ: Q: How does alignment change the ideal? A: Each alignment maps to a thematic ideal. Lawful characters lean toward order and tradition, chaotic toward freedom and change, good toward kindness and protection, and evil toward power or self-interest, mirroring D&D's alignment-keyed ideals. Q: Why are there two personality traits? A: D&D character sheets reserve space for two personality traits alongside a single ideal, bond and flaw. Rolling two traits matches that layout and gives the character a little more texture to roleplay. Q: Are these tied to a specific background? A: The lists are general fantasy archetypes rather than a single official background, so they work for any character. You can re-roll until a set fits the background and class you have chosen. Q: Can I re-roll just to get fresh ideas? A: Yes. Every click rolls a complete new set of traits, ideal, bond and flaw. It is a fast way to brainstorm personalities for player characters or NPCs you need on the spot. Q: Is anything sent to a server? A: No. All rolls happen locally in your browser from built-in lists. Nothing is uploaded, so the tool works offline and your characters remain private. #### Tech Lorem Generator URL: https://geratools.com/tech-lorem-generator Free tech lorem ipsum generator. Produce placeholder text peppered with developer jargon, framework names and engineering terms. Generate paragraphs, sentences or words for coding-tool and SaaS mockups, instantly and entirely in your browser. How to use: 1. Choose an amount and unit: Enter how much text you need and pick paragraphs, sentences or words. Paragraphs suit docs mockups; words suit nav items and labels. 2. Generate the jargon: Press Generate to assemble fresh developer-flavoured filler full of framework names and engineering verbs. Press again for a new mix. 3. Copy into your prototype: Click Copy and paste the text into your SaaS landing page, developer-tool UI, or documentation mockup as realistic technical placeholder copy. FAQ: Q: What is tech lorem ipsum? A: It is a themed placeholder text that swaps Latin for developer vocabulary — words like microservice, idempotent, deploy, Kubernetes and GraphQL. It fills the same role as standard Lorem Ipsum but makes coding-tool and SaaS mockups look authentically technical. Q: How is the text generated? A: Sentences are built from a small grammar that combines engineering verbs, adjectives, nouns and real technology names drawn from curated lists. The structure stays readable while the word choices are random, so the output reads like plausible engineering prose without conveying real meaning. Q: Can I generate short labels instead of paragraphs? A: Yes. Set the unit to words and choose a small count to get a short run of technical terms suitable for navigation items, buttons, tab labels or feature headings rather than full paragraphs. Q: Is the result reproducible? A: For a given amount and unit the output is stable on each render because a seeded random source drives the selection. Press Generate to advance the seed and produce a fresh arrangement of the same vocabulary. Q: Does any data leave my browser? A: No. Everything runs locally with no network requests. Your settings and the generated text stay on your device, so the tool works offline and your prototype copy stays private. #### Random Tier List Generator URL: https://geratools.com/tier-list-generator Paste a list of items and have them randomly assigned to S, A, B, C, D, and F tiers using a fair shuffle. A fun, neutral starting point for ranking debates, draft orders, and tier-list videos. Runs in your browser. How to use: 1. Enter your items: Type or paste one item per line into the items box — characters, foods, songs, anything you want to rank. 2. Generate the list: Click Generate to shuffle every item and distribute them evenly across the S through F tiers. 3. Re-roll or copy: Generate again for a fresh random arrangement, or copy the formatted result to share or paste into a video. FAQ: Q: How are items assigned to tiers? A: Items are first shuffled with a Fisher-Yates shuffle so the order is uniformly random. They are then dealt out evenly across the six tiers so each tier gets a roughly equal share, with any remainder pushed to the higher tiers. Q: Is the randomization actually fair? A: Yes. The Fisher-Yates algorithm gives every possible ordering an equal probability, so no item is biased toward any tier. Each click is an independent fresh shuffle. Q: Can I control how many items go in each tier? A: Not in random mode — that is the point of the tool. It spreads items as evenly as possible across all six tiers so the result is a neutral, unbiased starting layout you can then debate and adjust. Q: What do the tiers S to F mean? A: It is the classic gaming and internet ranking scale: S is the best or top tier, followed by A, B, C, D, and F as the worst. S sits above A because it originally stood for Special or Superior. Q: How many items can I rank? A: There is no hard limit beyond your browser's memory. The tool handles lists of dozens or hundreds of items, distributing them evenly across the six tiers each time you generate. #### Literary Fiction Writing Prompt Generator URL: https://geratools.com/writing-prompt-generator-literary Generate literary fiction prompts that centre character interiority, moral ambiguity, and quiet turning points. Covers domestic realism, family drama, grief, and existential themes for writers of serious short stories and novels. How to use: 1. Draw a prompt: Read the opening prompt, then click Generate to assemble a fresh character, situation, internal tension, and turning point. 2. Reroll for resonance: Press Generate until a scenario resonates emotionally rather than plot-wise. Literary prompts are meant to suggest a feeling, not a sequence of events. 3. Copy and interrogate: Copy the prompt into your notebook and ask what the character wants, what they fear, and what they refuse to admit. FAQ: Q: How is a literary prompt different from a genre prompt? A: Genre prompts lead with external events such as crimes or quests. Literary prompts lead with interiority and relationship, so this tool emphasises a character's inner tension and a quiet, often internal, turning point rather than a chase or a deadline. Q: Why are the situations so understated? A: Literary fiction often finds its drama in ordinary moments, such as a funeral afternoon or a silent dinner. The understated settings are deliberate, giving you space to make the emotional stakes do the work. Q: Can I combine elements from different draws? A: Absolutely. Mixing a character from one prompt with a tension from another is a good way to find an unexpected pairing. The tool is a spark, not a rule, so reshape any draw freely. Q: Is my data collected? A: No data is collected because there is nothing to submit. The character, situation, and tension banks are bundled into the page and run entirely in your browser. Q: What should I do after I have a prompt? A: Resist resolving the tension too quickly. The most rewarding literary stories sit inside the discomfort, so explore the character's contradictions and let the turning point be small and earned. #### Gamertag Generator URL: https://geratools.com/gamertag-generator Free gamertag generator that creates punchy gaming usernames from adjective and noun combos, with optional numbers and leetspeak. Tap any tag to copy. Runs entirely in your browser. How to use: 1. Pick your options: Toggle Add numbers and Leetspeak to control the style of the tags. 2. Generate tags: Click Generate gamertags to get eight fresh handles at once. 3. Copy your favourite: Tap any tag to copy it straight to your clipboard. FAQ: Q: What is leetspeak? A: Leetspeak swaps letters for similar-looking numbers, such as a to 4, e to 3, i to 1, and o to 0. Toggle it on for a more stylised look — for example ShadowWolf becomes Sh4d0wW0lf. Q: How does the generator create each tag? A: It picks one random adjective and one random noun and joins them. If Add numbers is on it appends a random number from 0 to 999. If Leetspeak is on it substitutes letters for look-alike digits. Q: Does it check if the tag is available? A: No. Tags are generated locally and are not checked against any gaming platform, so confirm availability when you register on Xbox, PSN, Steam or Discord. Q: How random are the gamertags? A: The random choices use the browser's crypto.getRandomValues with rejection sampling, so each adjective, noun and number is unbiased — not the predictable Math.random. Q: How many tags do I get at once? A: Each click generates eight fresh handles, so you can scan a batch and pick a favourite instead of rolling one at a time. Q: How do I copy a tag? A: Tap or click any generated tag and it is copied straight to your clipboard, with a brief confirmation. Q: Is anything sent to a server? A: No. Tags are built in your browser and never leave your device. #### Random Paragraph Generator URL: https://geratools.com/random-paragraph-generator Free random paragraph generator that creates random English sentences and paragraphs for mockups, writing prompts and testing. Runs entirely in your browser — nothing is uploaded. How to use: 1. Set the amount: Choose how many paragraphs or sentences you want and, for paragraphs, how many sentences each should contain. 2. Generate: The text updates instantly. Click Regenerate for a fresh random variation. 3. Copy: Click Copy to drop the generated text into your document, design or test. FAQ: Q: How is the text generated? A: Words are drawn from a common English word bank and assembled into sentences and paragraphs using a deterministic random number generator, so each Regenerate gives a fresh variation. Q: How much text can I generate? A: You can generate up to 100 paragraphs or sentences at a time, with up to 20 sentences per paragraph. Q: How is this different from Lorem Ipsum? A: Lorem Ipsum is pseudo-Latin placeholder text. This generator uses real common English words, so the output reads like plausible English — better when you want filler that still feels like a natural language for prototypes and content reviews. Q: Does each sentence start with a capital and end with a full stop? A: Yes. Each sentence is capitalised at the start and ends with a period, and longer sentences get a comma sprinkled in the middle, so the text looks naturally punctuated. Q: Can I control paragraph length? A: Yes. For paragraph mode you set how many sentences each paragraph contains (1 to 20), and how many paragraphs to produce (up to 100). In sentence mode you simply set how many standalone sentences you want. Q: Is the output the same every time? A: No. Each click of Regenerate draws new random words, so you get a fresh variation. There is no fixed seed. Q: Is anything sent to a server? A: No — the generator runs entirely in your browser. Nothing you produce is uploaded or stored. #### Email Signature Generator URL: https://geratools.com/email-signature-generator Free email signature generator. Fill in your details, pick a template, add a photo, social icons and a call-to-action button, then copy the HTML signature into Gmail, Outlook or Apple Mail. Runs entirely in your browser — nothing is uploaded. How to use: 1. Fill in your contact details: Add your name, job title, company, phone, email and website. Everything updates in the live preview as you type. 2. Choose a template and style: Pick from stacked, vertical, minimal or card layouts, then set your accent colour, font, size and photo shape. 3. Add a photo, social links and a button: Upload a headshot or logo, add LinkedIn or X links, and optionally a call-to-action button such as Book a call. 4. Copy or download the signature: Click Copy signature and paste it into Gmail, Outlook or Apple Mail, or download a standalone HTML file. FAQ: Q: How do I add this signature to Gmail? A: Click Copy signature, then in Gmail go to Settings, the gear icon, then See all settings, General, scroll to Signature, create a new signature and paste with Cmd or Ctrl plus V. Gmail keeps the formatting, photo and links intact. Q: How do I add it to Outlook? A: In desktop Outlook go to File, Options, Mail, Signatures, create a new entry and paste. In Outlook on the web go to Settings, Mail, Compose and reply, then paste into the signature box. Both keep the rich HTML formatting. Q: Will the photo and icons show up in every email client? A: The social icons are embedded as data URIs, so they render without any external request and survive image-blocking in most clients. Your uploaded photo is also embedded inline, which means it travels with the signature and does not depend on a hosted image URL. Q: Is my data private? A: Completely. Every field, your photo and the generated HTML stay in your browser. Nothing is uploaded to a server, and your draft auto-saves to local storage on your own device so it is still there when you return. Q: Why is the signature built from HTML tables? A: Email clients strip modern CSS layout such as flexbox and grid, so robust signatures use nested tables with inline styles. This generator outputs table-based, inline-styled markup so the layout holds up in Gmail, Outlook, Apple Mail and most mobile clients. Q: Can I include a legal disclaimer or confidentiality notice? A: Yes. There is a dedicated disclaimer field that renders as small grey text below your details, ideal for confidentiality notices, regulatory wording or an unsubscribe note for one-to-one business mail. ### Document & Business Builders #### Facebook / Meta Ad Copy Builder URL: https://geratools.com/ad-copy-builder-facebook Builds complete Facebook ad copy with three primary-text angles, a headline, a link description, and a CTA button, all formatted to Meta's field limits so you can launch and A/B test in minutes. How to use: 1. Describe your product and audience: Enter what you're selling and who it's for so the copy speaks to the right person. 2. Add your benefit and offer: State the main benefit, which becomes the headline, and any offer to weave into the hook. 3. Copy the variants: Pick a CTA button, then copy any of the three primary-text angles plus the headline and link description. FAQ: Q: What are Meta's ad copy character limits? A: Meta recommends primary text under about 125 characters before truncation, headlines under 40 characters, and link descriptions under 30 characters. This builder shows live counts for the headline and description so you stay within them. Q: Why generate three primary-text angles? A: Meta's algorithm optimizes best when you give it variations to test. The builder produces a problem-solution angle, a benefit-led angle, and a social-proof or urgency angle so you can run an A/B test from one set of inputs. Q: Which CTA button should I choose? A: Match the button to the action: Shop Now for ecommerce, Sign Up or Subscribe for lead gen, Book Now for services. The builder offers the standard Meta CTA set so your choice maps to a real button. Q: Will this copy comply with Meta's ad policies? A: The templates avoid prohibited claims, but you are responsible for policy compliance. Review Meta's advertising standards, especially for health, finance, and before-and-after claims, before launching. Q: Can I edit the generated copy? A: Yes. The output is a starting point built from your inputs. Copy it, then tweak wording, add your brand voice, and shorten anything that runs long before pasting into Ads Manager. #### Competitive Battle Card Builder URL: https://geratools.com/battle-card-builder Create a competitive battle card with a competitor's strengths and weaknesses, their top talking points paired with your counters, trap questions to ask the buyer, and land mines to avoid. Copies as Markdown. How to use: 1. Profile the competitor: Enter the competitor name and positioning, then list their genuine strengths and exploitable weaknesses. 2. Pair pitch with counters: List their top talking points and your line-matched counters so reps can respond to each one instantly. 3. Add traps and copy: Write trap questions to ask the buyer and land mines to avoid, then copy the generated Markdown battle card. FAQ: Q: What is a sales battle card? A: A battle card is a one-page reference that helps a sales rep win deals against a specific competitor. It summarizes the competitor's strengths and weaknesses, counters to their pitch, questions that expose their gaps, and traps your reps should avoid. Q: What are trap questions? A: Trap questions are questions you plant with the buyer that lead them to discover a competitor's weakness themselves, such as 'how long did your last rollout actually take?'. They are more persuasive than you criticizing the rival directly. Q: What are land mines in a battle card? A: Land mines are topics where you lose, so reps should steer away from them. Listing them — for example, not competing on raw integration count if you are behind there — keeps reps from walking into a comparison that favors the competitor. Q: Why pair their talking points with my counters? A: Reps need an instant, on-message response when a buyer repeats a competitor's pitch. Line-matching each claim to a prepared counter means there is no hesitation in the moment, and the messaging stays consistent across the whole team. Q: Is my battle card stored anywhere? A: No. The tool runs entirely in your browser and stores nothing. When the card is ready, use the copy button to put the Markdown on your clipboard and paste it into your enablement wiki or CRM. #### Birthday Wish Message Builder URL: https://geratools.com/birthday-wish-message-builder Generate a birthday message tailored to a friend, family member, colleague, boss, or client — in a sincere, funny, or formal tone — with fields for a personal detail, age or milestone, and your sign-off. How to use: 1. Enter the name and relationship: Add the recipient's name and pick whether they are a friend, family member, colleague, boss, or client. 2. Choose tone and add a detail: Select a sincere, funny, or formal tone and optionally add something specific you appreciate plus the age or milestone. 3. Copy the message: Review the generated greeting and copy it for a card, text, email, or social post. FAQ: Q: How do I make a birthday message feel personal? A: Name one specific thing about the person — a quality you admire or something they always do. 'Thank you for always being the one who checks in' lands far harder than 'hope you have a great day.' Specificity is the entire difference between a message that feels written for them and one that feels copied. Q: What tone fits a colleague or boss? A: Lean warm but professional. A sincere line acknowledging the pleasure of working together fits most workplace relationships; light humour can work if you know the person well. For a boss or client, avoid jokes about age or anything that could read as too familiar, and keep it brief and gracious. Q: Should I mention the person's age? A: Only if you know they are comfortable with it. Milestone birthdays like 30, 40, or 50 are often worth a celebratory nod for friends and family. For colleagues, bosses, and clients, it is safer to leave age out entirely — focus on well-wishes and appreciation instead. Q: Is a funny birthday message ever risky? A: Humour bonds people who know each other well, but it can misfire with looser relationships or anyone sensitive about aging. A safe rule: only joke as hard as your relationship can carry, and when in doubt with colleagues, bosses, or clients, choose the sincere or formal tone instead. Q: How long should a birthday message be? A: Short and genuine beats long and generic. Two or three sentences — a greeting, one personal touch, and a warm wish for the year ahead — is ideal for a card or text. Save longer notes for someone very close, where extra warmth is welcome rather than padding. #### Business Requirements Document (BRD) Builder URL: https://geratools.com/business-requirements-doc-builder Builds a complete business requirements document with business objectives, a stakeholder list, as-is and to-be analysis, business rules, numbered functional requirements, and a sign-off section ready to copy. How to use: 1. State objectives and stakeholders: Capture the business problem, the measurable objectives, and the people who own or are affected by the project. 2. Document current and future state: Describe the as-is process and the desired to-be state, then list the governing business rules. 3. Add requirements and export: Enter functional requirements one per line; the builder numbers them and assembles the full BRD for copy. FAQ: Q: What is a business requirements document? A: A BRD describes what a business needs from a project or system in business terms, not technical ones. It captures objectives, stakeholders, the current and target state, business rules, and the functional requirements that must be met for the project to succeed. Q: How is a BRD different from an FRS? A: A BRD states the business need and the why, written for stakeholders; a functional requirements specification details the how, written for engineers. The BRD usually comes first and the FRS is derived from it. Q: What goes in the as-is and to-be sections? A: As-is describes how things work today, including pain points and inefficiencies. To-be describes the desired future process once the project is delivered, making the gap and the value of the change explicit. Q: Why number the functional requirements? A: Numbering, such as FR-01, gives each requirement a stable identifier that can be referenced in test cases, design docs, and change requests. The builder numbers your requirements automatically as you add them. Q: Who signs off on a BRD? A: Typically the project sponsor, the business owner, and lead stakeholders. The sign-off block records names, roles, and dates so there is an auditable agreement on scope before build begins. #### Club / Organization Constitution Builder URL: https://geratools.com/club-constitution-builder Build a club constitution covering name, purpose, membership eligibility, officer roles, meeting frequency, voting and quorum, financial management, amendments, and a dissolution clause. Ready to adapt and adopt at your AGM. Not legal advice. How to use: 1. Name and define the club: Enter the club name, its purpose, and who is eligible to become a member. 2. Set the governance details: Choose how often the committee meets, the quorum for general meetings, and the financial year end. 3. Copy and adopt: Copy the generated constitution, review it with the founding members, and adopt it at your first general meeting. FAQ: Q: What is a club constitution for? A: A constitution is the governing document that sets out how a club runs — its purpose, who can join, who leads it, how decisions are made, and how money is handled. Banks, grant funders, and venues often require one before they will deal with a club. Q: What is a quorum? A: A quorum is the minimum number of members who must be present for a meeting's decisions to be valid. Setting it too high can stall the club; too low lets a tiny group bind everyone. A third of the membership is a common starting point. Q: Why include a dissolution clause? A: A dissolution clause says what happens to the club's assets if it closes. For non-profit clubs it usually directs any surplus to a similar organisation rather than to members, which keeps the club genuinely not-for-profit and is often required for grants. Q: How are amendments handled? A: The template requires a two-thirds majority at a general meeting, with the proposed change set out in the notice. This protects the constitution from being changed casually while still allowing the membership to update it when needed. Q: Is this the same as nonprofit bylaws? A: They overlap, but a constitution is the broader founding document for clubs and societies, while bylaws are the more detailed operating rules of an incorporated nonprofit. For a registered charity or company, use the nonprofit bylaws builder as well. #### Conference Session Schedule Builder URL: https://geratools.com/conference-schedule-builder Create a multi-track conference schedule grid with time slots down the side and tracks across the top, filling each cell with a session title, speaker, and room or join link. Exports a clean Markdown grid attendees can scan at a glance. How to use: 1. Define your tracks: Name each parallel track that runs at the same time, such as a main stage, a workshop room, and a community track. 2. Add time slots: Add the time slots that structure the day. Each slot becomes a row spanning every track. 3. Fill the grid and export: For each track within each slot, enter a session title, speaker, and room or link, then copy the Markdown grid. FAQ: Q: What is a track in a conference schedule? A: A track is one of several parallel session streams running at the same time. Attendees choose which track to follow in each slot. Tracks usually group by theme, audience level, or room, so a single time slot might offer a beginner talk, an advanced talk, and a hands-on workshop simultaneously. Q: How many tracks should a conference have? A: It depends on attendance. A rule of thumb is one track per roughly 100 to 150 attendees so each room stays reasonably full. Small events run fine single-track; large conferences may run five or more, but every extra track forces attendees to miss more content. Q: Should every track have a session in every slot? A: Not necessarily. You can leave a cell empty when a track has no session in that slot, or use shared slots for plenary keynotes and meals that span all tracks. The builder lets you leave any cell blank and it simply renders as empty in the grid. Q: How do I avoid scheduling conflicts? A: Spread popular or related talks across different time slots rather than putting them head to head, and avoid pitting two sessions for the same audience against each other in the same slot. Reviewing the full grid at once, as this tool shows it, makes conflicts easy to spot. Q: Can I use this for a virtual conference? A: Yes. For virtual events, put the join link or stream name in the room field of each cell. The exported grid works equally well as an in-person room map or a list of where to click for each online session. #### Email Drip Campaign Builder URL: https://geratools.com/drip-campaign-builder Builds a 5-7 email drip campaign with a trigger event, delay between emails, subject lines, body copy outlines, and a CTA for each email. Choose welcome, onboarding, nurture, or trial-conversion goals to get a tailored cadence. How to use: 1. Pick a campaign goal: Choose welcome, onboarding, lead nurture, or trial conversion. Each goal maps to a different email arc and cadence. 2. Add your product and CTA: Enter your product name, the audience, and the primary action you want subscribers to take. 3. Review the cadence: The tool lays out each email with its trigger, delay, subject line, body outline, and call to action ready to load into your ESP. FAQ: Q: How many emails should a drip campaign have? A: Most effective drips run 5-7 emails. Welcome and onboarding series tend toward the shorter end, while nurture campaigns can stretch longer. Fewer than four rarely builds enough momentum, and more than eight risks fatigue without a clear reason. Q: What delay should I use between drip emails? A: Start with a same-day or next-day first email while interest is high, then space the rest 2-4 days apart. The tool front-loads the early emails and widens the gaps later, which matches how attention naturally fades. Q: What triggers a drip campaign? A: A drip starts from a defined event — a signup, a trial start, a download, or inactivity. The tool labels each email with its trigger and the delay from the previous step so you can wire it directly into your automation platform. Q: Should every drip email have a CTA? A: Yes, one clear call to action per email. Multiple competing CTAs split attention and lower clicks. The tool assigns a single primary action per email that advances the subscriber toward the campaign goal. Q: Does this tool store my campaign? A: No. The campaign is generated in your browser from the fields you enter and is not saved or uploaded anywhere. Copy the output into your email platform to keep it. #### Google Play Store Full Listing Builder URL: https://geratools.com/google-play-store-listing-builder Generates a complete Google Play store listing — an 80-character short description and a structured full description up to 4000 characters with a pitch, feature bullets, natural keyword integration, and a What's New section — with live counts against both Play limits. How to use: 1. Enter the basics: Add the app name, an 80-character short description, and a one or two sentence opening pitch. 2. Add features and keywords: List your keywords and key features one per line so the builder can weave terms in and structure the body. 3. Copy both descriptions: Review the live character counts, then copy the short and full descriptions into the Google Play Console store listing fields. FAQ: Q: What are the Google Play description limits? A: Google Play allows up to 80 characters for the short description and up to 4000 characters for the full description. This builder shows a live count for each and warns you when you exceed either limit. Q: Does the full description affect Play Store ranking? A: Yes. Unlike iOS, Google Play indexes the full description text for search, so naturally including your key terms there helps discoverability. The builder weaves your keywords into a sentence rather than stuffing them, which Play penalizes. Q: What makes a good short description? A: The short description appears prominently above the fold and is often the deciding factor for an install, so it should state the core value in under 80 characters. Lead with the benefit, not the app category. Q: How should I structure the full description? A: A strong structure is a hook, a feature list, a why-you'll-love-it section, and a What's New note. The builder assembles exactly this layout with scannable bullet points, which converts better than a wall of text. Q: Should I keyword-stuff the description? A: No. Google Play actively penalizes repetitive keyword stuffing and it reads poorly to users. The builder mentions each key term naturally once, which is what Play's guidelines and ranking reward. #### ICS / iCal Event Builder URL: https://geratools.com/ics-builder Free ICS event builder — fill in a title, time, location, recurrence, and reminder, and download a valid RFC 5545 .ics file you can import into Google Calendar, Apple Calendar, or Outlook. Everything is generated in your browser. How to use: 1. Fill in the event: Enter the title, start and end times, location, and description. 2. Add recurrence or a reminder: Optionally set a repeat rule and a reminder offset such as 15 minutes before. 3. Download the .ics: Click Download to save the generated file, then open it in any calendar app to import the event. FAQ: Q: Which calendar apps can open the file? A: Any app that supports the iCalendar standard, including Google Calendar, Apple Calendar, Microsoft Outlook, and Thunderbird. The file follows RFC 5545, the format every major calendar imports. Q: How do all-day events work? A: When you tick All day, the builder writes DTSTART and DTEND as a date value (VALUE=DATE) instead of a date-time. Per the standard, DTEND is the day after the last day, so a one-day event ends the following date. Q: What does the reminder do? A: It adds a VALARM block with a DISPLAY action and a negative trigger such as -PT15M, which tells the calendar to alert you 15 minutes before the event starts. Q: How is recurrence stored? A: As an RRULE line, for example FREQ=WEEKLY for a weekly repeat. You can also set how many times it repeats with COUNT, which caps the series at that number of occurrences. Q: Is my event data uploaded? A: No. The .ics text is assembled entirely in your browser and the file is created locally, so nothing about your event is sent to a server. #### Informed Consent Form Builder URL: https://geratools.com/informed-consent-form-builder Build an informed consent form covering procedure description, material risks, expected benefits, alternatives, voluntary participation, confidentiality, and a signature block. For medical, surgical, dental, or research use. Not legal or medical advice. How to use: 1. Set the context: Choose whether the consent is for a medical, surgical, dental, or research procedure so the wording adapts. 2. Describe risks and benefits: Enter the specific procedure, its material risks, expected benefits, and the reasonable alternatives that were discussed. 3. Copy the document: Copy the generated consent text into your patient pack or research protocol and have a qualified professional review it. FAQ: Q: What makes consent legally informed? A: Informed consent requires that the person understands the nature of the procedure, its material risks, the expected benefits, and the reasonable alternatives, and gives consent voluntarily. This builder structures all four elements plus confidentiality and a signature block. Q: What is the difference between medical and research consent? A: Research consent emphasises that participation is voluntary and can be withdrawn at any time without affecting ordinary care. The builder switches to that wording when you select the research context. Q: Are these material risks the right ones for my procedure? A: The risks field is a placeholder. You must replace it with the specific material risks a reasonable patient would want to know for your exact procedure, as advised by the treating clinician. Q: Do I need a witness signature? A: It depends on your jurisdiction, the procedure, and whether the patient can sign for themselves. The template includes an optional witness line; keep it where local rules or your protocol require an independent witness. Q: Is this a substitute for legal review? A: No. It is a structured starting template. Consent law and disclosure standards vary by country and procedure, so have a qualified legal and clinical reviewer approve the final wording before use. #### Internship Report Builder URL: https://geratools.com/internship-report-builder Generates an internship report with organization background, objectives, activities performed, skills gained, challenges, and recommendations sections — formatted for university and college submission. How to use: 1. Enter placement details: Add your name, the organization, your role, and the internship dates so the report header is complete. 2. Describe your work: Fill in your objectives, the activities you performed, and the skills you gained during the placement. 3. Copy the report: Add the challenges you faced and your recommendations, then copy the fully structured report ready to submit. FAQ: Q: What sections does a standard internship report need? A: Most institutions expect an introduction with organization background, objectives, a description of activities performed, skills and competencies gained, challenges encountered, and recommendations or conclusions. This builder produces all six in order. Q: How long should an internship report be? A: Length varies by program, but a focused report of three to eight pages is typical. The builder gives you concise, well-structured sections you can expand with specific examples to reach your required length. Q: Should I describe specific tasks? A: Yes. Vague reports lose marks. List concrete activities — the systems you used, the deliverables you produced, the meetings you attended — so the report shows what you actually did rather than what you observed. Q: How do I write the challenges section without sounding negative? A: Frame each challenge as a problem you encountered and what you learned from it. The builder positions challenges as learning moments, which demonstrates reflection and maturity to an assessor. Q: Can I use this report for any field? A: Yes. The structure — background, objectives, activities, skills, challenges, recommendations — applies to engineering, business, healthcare, and any other internship. Fill the fields with details specific to your placement. #### Letter of Good Standing Request Builder URL: https://geratools.com/letter-of-good-standing-request-builder Create a formal letter requesting a certificate of good standing from a company registrar, state office, or professional body, stating the entity, registration number, the purpose, your timeline, and delivery instructions. How to use: 1. Enter the entity details: Provide your entity name and registration number exactly as recorded, plus the registrar or authority you are writing to. 2. State the purpose and timeline: Explain why you need the certificate — opening a bank account, a foreign filing, a tender — and any date by which you need it. 3. Add delivery instructions: Specify how you want the certificate delivered, add your contact details, then copy and send the letter. FAQ: Q: What is a certificate of good standing? A: It is an official document from a registrar confirming that an entity legally exists, is properly registered, and is up to date with its filings and fees. It is also called a certificate of existence or certificate of compliance depending on the jurisdiction. Q: When do I need one? A: Commonly when opening a corporate bank account, registering to do business in another state or country, applying for financing, entering a contract or tender, or completing a merger or acquisition. The counterparty wants proof your entity is in good legal standing. Q: Who issues it? A: The body that maintains the official register for your entity type — Companies House in the UK, a Secretary of State office in the US, or the relevant professional or regulatory body. Address your request to that registrar. Q: Will the certificate be issued automatically? A: Only if your filings and fees are current. If returns are overdue or fees are unpaid, the registrar will usually refuse until you bring the account up to date, which is why the letter asks them to flag any outstanding action. Q: Is my company information stored? A: No. The builder runs entirely in your browser. The entity name, registration number, and contact details you enter are never uploaded or saved on a server. #### Performance Review Builder (Self-Assessment) URL: https://geratools.com/performance-review-builder Self-assessment builder covering goals achieved, key accomplishments with metrics, areas for growth, and a development plan for the coming year — structured to make your impact clear to your manager. How to use: 1. List your goals and results: Enter each goal you were set and what you actually achieved against it so the review opens with outcomes. 2. Add accomplishments with metrics: List your biggest wins and quantify them — percentages, revenue, time saved — because numbers make impact undeniable. 3. Copy the self-assessment: Add growth areas and a development plan, then copy the assembled self-evaluation ready to paste into your review form. FAQ: Q: How do I make a self-assessment stand out? A: Quantify everything. A manager remembers measurable impact, so pair each accomplishment with a number — revenue, percentage, hours saved, or volume. This builder gives every accomplishment a metric field to encourage that. Q: Should I mention areas where I fell short? A: Yes, briefly and constructively. Naming a genuine growth area paired with a concrete plan shows self-awareness and is more credible than claiming everything went perfectly. The builder has a dedicated growth-areas section. Q: How do I write the development plan? A: Tie each growth area to a specific action for the coming year — a course, a stretch project, or a mentor. This turns a weakness into a forward plan, which managers reward in ratings discussions. Q: How long should a self-assessment be? A: Aim for substance over length — a focused page that a busy manager can skim is ideal. The builder keeps each section tight so the most important results are easy to find. Q: Can I reuse this for a mid-year review? A: Yes. The same structure — goals, accomplishments, growth areas, development plan — works for mid-year and annual reviews. Just scope the inputs to the period being reviewed. #### Performance Review Builder (Manager Feedback) URL: https://geratools.com/performance-review-manager-builder Manager review builder with sections for performance against goals, behavioral competencies, strengths, development areas, and next-period objectives — designed to keep feedback specific, balanced, and defensible. How to use: 1. Set the rating and context: Enter the employee's name, role, period, and an overall rating so the review opens with a clear summary judgment. 2. Document performance and behaviors: Record results against goals and rate behavioral competencies, then list specific strengths and development areas with examples. 3. Copy the review: Add next-period objectives, then copy the assembled, balanced review ready for your HR system or 1:1. FAQ: Q: How do I keep manager feedback fair and defensible? A: Tie every point to a specific, observable example rather than a personality judgment. This builder structures strengths and development areas as evidence-based bullets, which keeps the review objective and consistent across your team. Q: What is the difference between goals and competencies? A: Goals are the what — the measurable results delivered this period. Competencies are the how — collaboration, communication, ownership. A complete review covers both, so this builder separates a goals section from a behavioral-competencies section. Q: Should a review be all positive or all critical? A: Neither. A balanced review names genuine strengths and one or two real development areas. Lopsided reviews lose credibility and provide no path forward, so the builder prompts for both. Q: How specific should development areas be? A: Very. Pair each area with a concrete example and a forward action rather than a vague label. The builder encourages an example plus a next step so the employee knows exactly what to change. Q: How do I set good next-period objectives? A: Make them SMART — specific, measurable, achievable, relevant, time-bound. The builder gives each objective its own line so you can phrase them as concrete commitments rather than aspirations. #### Project Timeline / Gantt Outline Builder URL: https://geratools.com/project-timeline-builder Creates a structured project timeline with phases, tasks, owners, start and end dates, computed durations, dependencies, and milestone markers — formatted as a clean text outline you can copy into any tool. How to use: 1. Add each task: Enter a task name, owner, start date, and end date for every item in your plan. 2. Mark milestones and dependencies: Flag key deliverables as milestones and note which task each one depends on. 3. Copy the timeline: Review the computed durations and sorted schedule, then copy the outline into your doc or tracker. FAQ: Q: How is task duration calculated? A: Duration is the number of calendar days between the start and end dates, inclusive of both. The builder parses the two dates, computes the difference, and shows the result in days for every task. Q: Can I show dependencies? A: Yes. Each task has a 'depends on' field where you name the predecessor task. The outline prints the dependency next to the task so reviewers can see the critical path at a glance. Q: What is a milestone in this tool? A: A milestone is a zero-duration checkpoint marking a key deliverable, like a launch or sign-off. Tick the milestone box and the task is rendered with a marker so it stands out in the timeline. Q: Does it sort tasks by date? A: Yes. The generated outline sorts tasks by start date so the timeline reads top-to-bottom in chronological order, even if you entered them out of sequence. Q: Is this a real Gantt chart? A: It is a text-based Gantt outline — phases, tasks, dates, durations, and dependencies in copy-friendly form. It is ideal for plans, emails, and tickets where an image chart would be overkill. #### Student Recommendation Letter Builder URL: https://geratools.com/recommendation-letter-student Teacher and professor tool that turns a student's accomplishments, character traits, and a specific story into a ready-to-send formal recommendation letter for college or grad school, with correct pronouns throughout. How to use: 1. Add your details and the student: Enter your name and title, the student's name and pronoun, and how long you have taught or known them. 2. Provide academics, character, and a story: Describe the student's academic strengths with specifics, their character, and one concrete anecdote. 3. Copy and sign: Copy the assembled letter, replace any bracketed prompts, personalise the wording, and sign it. FAQ: Q: What makes an admissions recommendation stand out? A: Specific evidence and a memorable story. Admissions readers see thousands of letters calling students 'bright and hardworking', so a concrete anecdote that shows character in action is what they remember. The builder asks for exactly that to lift your letter above generic praise. Q: Should I address it to a specific person? A: Usually it goes to the admissions committee, which the builder uses by default. If a program names a specific contact, you can edit the greeting in the copied text. The opening establishes your standing to recommend the student either way. Q: How long should a student recommendation be? A: Typically one page. Long enough to cover academics, character, and one strong story, but disciplined enough that every line earns its place. The builder produces a focused letter you can trim rather than a padded one you have to cut down. Q: What if I can only recommend the student moderately? A: Be honest but kind. A lukewarm letter can hurt a student, so if you cannot write a genuinely strong recommendation it is often better to decline. When you do write one, the specifics you supply keep it credible rather than inflated. Q: Is anything I enter stored or uploaded? A: No. The builder works entirely in your browser. The student's details, your story, and your name are assembled into a letter locally and never sent anywhere — it leaves your device only when you copy it. #### Customer Service Resume Builder URL: https://geratools.com/resume-builder-customer-service Free customer service resume builder with support-specific sections for metrics (CSAT, FCR, AHT, NPS), tools (Zendesk, Salesforce, Intercom), channels handled, escalation and de-escalation, and training experience. Live preview, copy or download. How to use: 1. Lead with your support metrics: Add the numbers hiring managers screen for — CSAT, first-contact resolution, average handle time, and ticket volume — in their own section. 2. List your tools and channels: Name the helpdesk and CRM tools you use (Zendesk, Salesforce, Intercom) and the channels you cover (chat, email, phone, social). 3. Copy or download: Watch the live preview build as you type, then copy the text or download a plain-text resume. FAQ: Q: Which metrics matter most on a customer service resume? A: CSAT (satisfaction), first-contact resolution (FCR), average handle time (AHT), ticket or call volume, and NPS where you have it. These quantify your impact better than adjectives, so this builder gives them their own metrics section near the top. Q: Should I list the support tools I have used? A: Yes — helpdesk and CRM fluency is a hard requirement on most support roles. Name the platforms you have actually used (Zendesk, Salesforce Service Cloud, Intercom, Freshdesk, ServiceNow) so both recruiters and keyword filters match you. Q: How do I show escalation and de-escalation skill? A: Describe the outcome: retained an at-risk account, resolved a complaint that had been escalated twice, or reduced repeat escalations on your queue. The dedicated escalation field keeps this distinct from routine ticket handling. Q: Does training or mentoring experience help? A: Strongly. Onboarding new agents or writing macros and help-center articles signals you can scale a team, not just clear your own queue — which matters for senior and team-lead support roles. List it with the number of agents trained or articles published. Q: Is my data uploaded anywhere? A: No. The builder runs entirely in your browser. Your draft saves to local storage on your own device and the export is generated locally — nothing is sent to a server. #### RRULE / Recurring Event Builder URL: https://geratools.com/rrule-builder Visual builder for RFC 5545 RRULE strings — set frequency, interval, BYDAY, BYMONTH, BYMONTHDAY, COUNT and UNTIL, then preview the next occurrences before pasting into any ICS file or calendar API. No network calls. How to use: 1. Pick the frequency and interval: Choose DAILY, WEEKLY, MONTHLY or YEARLY and set the interval (every N units). For example, frequency WEEKLY with interval 2 means every other week. 2. Add the qualifiers: For weekly rules select the weekdays (BYDAY); for monthly and yearly rules set the day of month (BYMONTHDAY) and, for yearly, the months (BYMONTH). 3. Set the end and copy the result: Choose Never, a COUNT of occurrences, or an UNTIL date. Check the occurrence preview, then copy the RRULE string with or without the DTSTART line. FAQ: Q: What is an RRULE? A: RRULE is the recurrence rule property defined by RFC 5545 (the iCalendar standard). It is a single semicolon-separated string such as FREQ=WEEKLY;BYDAY=MO,WE;COUNT=10 that tells a calendar how to repeat an event without listing every date. Q: What is the difference between COUNT and UNTIL? A: COUNT limits the recurrence to a fixed number of occurrences, while UNTIL ends it on a specific date. RFC 5545 says a rule must not contain both; this builder lets you pick one or the other so the output stays valid. Q: How does the UNTIL value get formatted? A: UNTIL is written as a UTC date-time stamp ending in Z, set to 23:59:59 on your chosen date so the final day's occurrences are included. This matches how Google Calendar and Apple Calendar interpret the field. Q: Why does the preview only show 12 dates? A: The preview is capped at the first 12 occurrences purely to keep the UI fast and readable. The RRULE string itself is unbounded (or bounded by your COUNT/UNTIL) and will expand to all occurrences in your calendar app. Q: Does this send my data anywhere? A: No. The rule is assembled and the occurrences are computed entirely in your browser using plain JavaScript date math. Nothing is uploaded or stored on a server. #### Savings Goal Tracker Builder URL: https://geratools.com/savings-goal-tracker-builder Build a savings plan for a specific goal — house deposit, vacation, emergency fund. Computes the required monthly contribution, months to target, milestone dates at 25/50/75/100%, and an optional interest boost. Exports clean Markdown. How to use: 1. Name the goal and amount: Enter what you are saving for, the target amount, and anything you have already put aside. 2. Set contribution or deadline: Either enter how much you can save each month, or a target date — the tool computes the missing one. 3. Review milestones and export: See the months to target and dated 25/50/75/100% milestones, then copy the Markdown plan. FAQ: Q: How is the required monthly contribution calculated? A: The tool takes the amount still needed — target minus what you have already saved — and divides it by the number of months until your deadline. If you instead enter a fixed monthly amount, it divides the remaining amount by that contribution to find how many months the goal will take. Q: What are the milestones for? A: Big goals feel abstract, so the tool marks the 25%, 50%, 75%, and 100% points with the amount and the projected date you reach each. Hitting a concrete milestone is far more motivating than staring at a distant final number, and the dates let you check whether you are on pace. Q: Does it account for interest? A: Optionally. If you enter an annual savings rate, the plan notes the rough interest boost over the period so you can see that a high-yield account shortens the journey. For short goals the effect is small; for multi-year goals it can be meaningful, so it is worth including. Q: Should I use a separate account for each goal? A: Yes — a named, separate account stops goal money from blending into everyday spending and makes progress visible. Automating the monthly transfer on payday is the single highest-impact habit, because money you never see in your current account is money you do not spend. Q: Is this financial advice? A: No. The tool performs simple arithmetic on the figures you enter and formats a plan. It does not recommend products or returns. Rates and your circumstances vary, so treat the output as a planning guide and confirm details with your bank or a qualified adviser. #### Statement of Work (SOW) Builder URL: https://geratools.com/statement-of-work-builder Build a professional Statement of Work covering project background, scope, deliverables, milestones with dates, a payment schedule, assumptions, and a change-order process. Copyable and printable. How to use: 1. Describe the project and scope: Enter the project title, the parties, a background paragraph, and a clear scope statement of what is and isn't included. 2. List deliverables, milestones, and payments: Add each deliverable, each milestone with its target date, and each payment tied to a milestone or percentage. 3. Add assumptions and copy the SOW: Note any assumptions and the change-order process, then copy or print the full Statement of Work. FAQ: Q: What is a Statement of Work? A: A Statement of Work (SOW) is a document that defines exactly what a project will deliver, when, and on what terms. It typically sits under a master services agreement and covers scope, deliverables, milestones, payment, assumptions, and how changes are handled. It turns a vague engagement into a clear, agreed plan. Q: What is the difference between scope and deliverables? A: Scope describes the boundaries of the work — what is and isn't included overall. Deliverables are the specific tangible outputs the client receives, such as a design file, a deployed app, or a report. Listing both prevents scope creep and disputes about what was promised. Q: Why include an out-of-scope section? A: Stating what is explicitly NOT included is the single most effective way to prevent scope creep. It sets clear expectations and gives you a reference point when the client requests extra work, which then flows through the change-order process. Q: How should I tie payments to milestones? A: Linking each payment to an accepted deliverable or milestone protects both sides: the client pays for progress they can verify, and you get paid as you go rather than only at the end. Common patterns are a deposit, progress payments, and a final balance on acceptance. Q: Is my SOW stored anywhere? A: No. The document is assembled in your browser and your draft stays on your device only. Nothing is uploaded or shared. #### Technical Interview Rubric Builder URL: https://geratools.com/technical-interview-rubric-builder Build a structured technical interview rubric: list the skills you assess, define behavioral indicators for each 1-4 rating level, and get calibration guidance so different interviewers score consistently. Exports a ready-to-use Markdown rubric. How to use: 1. List the skills to assess: Add each competency you will evaluate, such as problem solving, code quality, and communication. 2. Define the rating levels: For each skill, write what a 1, 2, 3, and 4 look like as observable behaviors rather than vague impressions. 3. Export and calibrate: Copy the rubric and share the calibration notes so every interviewer applies the same bar. FAQ: Q: Why use a rubric for technical interviews? A: A rubric replaces gut feeling with defined criteria, which makes hiring decisions more consistent, more defensible, and less prone to bias. Interviewers score the same observable behaviors instead of relying on an overall vibe. Q: What is a behavioral indicator? A: A behavioral indicator is a concrete, observable description of what a given rating looks like — for example, 'asks clarifying questions before coding' rather than 'good communication'. Concrete indicators let two interviewers reach the same score from the same evidence. Q: Why a 4-point scale instead of 5? A: An even-numbered scale removes the safe middle option, forcing the interviewer to decide whether a candidate is above or below the bar. A 1-4 scale typically maps to strong no, lean no, lean yes, strong yes. Q: How do I calibrate across interviewers? A: Calibration means everyone shares the same definition of each rating before interviews begin, then reviews a few sample scores together to align. Periodically comparing how different interviewers scored the same candidate keeps the bar from drifting. Q: Should every skill weigh the same? A: Not necessarily. Weight skills by how much they predict success in the actual role — a backend role might weigh system design heavily and front-end polish lightly. Document the weighting so scores combine into a fair overall recommendation. #### Vendor Evaluation Matrix Builder URL: https://geratools.com/vendor-evaluation-matrix-builder Builds a weighted vendor scoring matrix with custom criteria and weights, scores up to six vendors on a 1–10 scale, and computes weighted totals plus a recommended winner for any procurement decision. How to use: 1. Define your criteria and weights: List the factors that matter — price, support, features — and assign each a weight that reflects its importance. 2. Score each vendor: Rate every vendor from 1 to 10 on each criterion based on your research or RFP responses. 3. Read the recommendation: The matrix computes a weighted total for each vendor and highlights the highest-scoring option to copy and share. FAQ: Q: How does a weighted scoring matrix work? A: Each vendor's score on a criterion is multiplied by that criterion's weight, and the products are summed into a weighted total. Higher-weighted criteria influence the result more, so the matrix reflects what actually matters to you. Q: Do the weights need to add up to 100? A: Not necessarily. The builder normalises weights internally, so you can use any positive numbers — relative size is what counts. Many teams use percentages that total 100 simply because it is easy to reason about. Q: How many vendors can I compare? A: Up to six vendors and as many criteria as you need. The recommendation always reflects the highest weighted total across the vendors you have scored. Q: What scoring scale should I use? A: A 1-to-10 scale per criterion is the default and works well for most decisions. Be consistent — define what a 10 means for each criterion before scoring so vendors are judged on the same bar. Q: Is the matrix saved anywhere? A: No. Everything runs locally in your browser, so confidential vendor names, prices, and scores never leave your device. Copy the output to save it. ### Languages & Scripts #### Number to Words Converter — Western & Indian (Lakh/Crore) System URL: https://geratools.com/number-to-words-converter Free number-to-words converter supporting both Western grouping (thousands, millions, billions) and the Indian system (lakhs, crores, arabs, kharabs). Handles whole numbers and decimals up to 999 trillion. Optional currency labels for ₹ INR, $ USD, £ GBP, ৳ BDT and ₦ NGN. Runs entirely in your browser — nothing sent to any server. How to use: 1. Type your number: Enter any whole or decimal number up to 999 trillion (or 999 kharab in Indian system). You can include a decimal point for amounts like 1234.56. 2. Choose the numbering system: Select "Western" for thousands, millions, billions grouping, or "Indian" for the lakh, crore, arab, kharab system used across South Asia. 3. Add a currency label (optional): Pick a currency (INR, USD, GBP, BDT, NGN) to append the correct unit words — e.g. "One lakh twenty-three thousand four hundred fifty-six rupees and seventy-eight paise". FAQ: Q: Does this tool send my numbers to any server? A: No. All conversion logic runs entirely in your browser using JavaScript. No data is transmitted or stored anywhere. Q: What is the Indian numbering system? A: The Indian system groups numbers differently from Western convention. After thousands, groupings go in pairs — 1,00,000 = 1 lakh, 1,00,00,000 = 1 crore, 1,00,00,00,000 = 1 arab, and 1,00,00,00,00,000 = 1 kharab. This is the standard used in India, Pakistan, Bangladesh, Nepal and Sri Lanka. Q: Can I use this for cheques and financial documents? A: Yes, the output format ("One lakh twenty-three thousand...") follows the style commonly required on cheques. Always double-check the result before using it on a legal or financial document. Q: How do I write 100000 in words in the Indian system? A: 100000 is "one lakh". In the Western system the same number reads "one hundred thousand". The tool shows whichever you select, and adds a currency suffix like "one lakh rupees" when you pick INR. Q: How are decimals like 1234.56 handled? A: The integer and fractional parts are converted separately. 1234.56 becomes "one thousand, two hundred thirty-four" plus "fifty-six" for the decimal, and with a currency selected it reads "one thousand two hundred thirty-four rupees and fifty-six paise". Q: What is the largest number this converter handles? A: It handles whole numbers up to 999 trillion in the Western system (and up to the kharab range, ~999 kharab, in the Indian system), with up to two decimal places shown as the minor currency unit. Q: Does it convert zero and negative numbers? A: Yes. Zero is written as "zero", and a leading minus sign is recognised so negative amounts are prefixed accordingly before the spelled-out value. #### Arabic Abjad Numerology Calculator URL: https://geratools.com/arabic-abjad-calculator Compute the traditional abjad (hisab al-jummal) numeric value of any Arabic word or phrase, summing each letter from أ=1 through غ=1000, with a per-letter breakdown and digital root. Runs entirely in your browser with no data uploaded. How to use: 1. Type Arabic text: Enter any Arabic word or phrase. Vowel marks and tatweel are ignored automatically. 2. Read the total: The tool sums each letter's abjad value and shows the running total plus its digital root. 3. Inspect the breakdown: Each letter is listed with its individual value so you can verify or learn the order. FAQ: Q: What is the abjad system? A: Abjad, or hisab al-jummal, is the traditional Arabic practice of assigning a number to each letter. The first nine letters are 1 to 9, the next nine are 10 to 90, and the rest run 100 to 1000. Summing the letters of a word gives its abjad value, used historically for chronograms, dates, and numerology. Q: Which abjad order does this use? A: It uses the standard Eastern (Mashriqi) order: أ=1, ب=2, ج=3, د=4, ه=5, و=6, ز=7, ح=8, ط=9, ي=10, ك=20, ل=30, م=40, ن=50, س=60, ع=70, ف=80, ص=90, ق=100, ر=200, ش=300, ت=400, ث=500, خ=600, ذ=700, ض=800, ظ=900, غ=1000. The Western (Maghribi) order differs for several letters and is not used here. Q: How are hamza and alif variants counted? A: All alif and hamza-bearing forms (ا أ إ آ ء ئ ؤ) reduce to the value 1, and ta marbuta (ة) counts as 5 like ha (ه). This matches conventional abjad practice where the carrier seat does not change the value. Q: What is the digital root shown? A: The digital root is the single digit you reach by repeatedly adding the digits of the total. For example 92 gives 9+2=11, then 1+1=2. Numerologists often reduce an abjad sum this way; it is shown for convenience alongside the full total. Q: Are vowel marks counted? A: No. Short-vowel harakat, tanwin, shadda, sukun, the dagger alif, and the tatweel elongation mark carry no abjad value and are stripped before counting, so only the consonantal skeleton contributes to the sum. #### Arabic IPA Transcription Tool URL: https://geratools.com/arabic-ipa-transcriber Convert harakat-vowelled Modern Standard Arabic to IPA in your browser, including pharyngeals (ħ ʕ), emphatic consonants (sˤ tˤ dˤ ðˤ), uvulars (q χ ʁ), gemination from shadda, and long vowels. How to use: 1. Paste vowelled Arabic: Enter Arabic text with harakat (fatḥa, kasra, ḍamma, sukūn, shadda). Unvowelled text transcribes consonants only. 2. Read the IPA: Each letter maps to its Modern Standard Arabic IPA value, with shadda producing gemination and long vowels from mater lectionis. 3. Verify the emphatics: Check that ص ط ض ظ surface as the pharyngealized /sˤ tˤ dˤ ðˤ/ and that ح ع render as the pharyngeals /ħ ʕ/. FAQ: Q: What are the pharyngeals ħ and ʕ? A: ح is the voiceless pharyngeal fricative /ħ/ and ع is the voiced pharyngeal fricative /ʕ/. Both are produced by constricting the pharynx and have no English equivalent, which is why explicit IPA symbols matter. Q: How does shadda work? A: Shadda (ّ) marks gemination — a doubled consonant. The tool repeats the IPA of the consonant it sits on, so رَبّ transcribes with /bb/. A harakat on a shadda'd letter still applies after the geminate. Q: Are emphatic consonants shown? A: Yes. ص ط ض ظ are the emphatic (pharyngealized) counterparts of س ت د/ذ and surface as /sˤ tˤ dˤ ðˤ/ with the superscript ˤ diacritic in IPA. Q: Does it transcribe long vowels? A: Long vowels appear when ا و ي act as matres lectionis after the matching short vowel, giving /aː uː iː/. Unvowelled text cannot disambiguate these, so add harakat for accurate vowel length. #### Arabic Sun/Moon Letter Checker URL: https://geratools.com/arabic-lam-assimilation-checker Classify each Arabic word by its leading letter as a sun letter, where the lam of al- assimilates and doubles (ash-shams), or a moon letter, where the lam stays pronounced (al-qamar). Runs entirely in your browser with a clear color-coded breakdown. How to use: 1. Enter Arabic text: Type or paste Arabic words. A leading al- definite article is skipped so the next letter is tested. 2. Read the labels: Each word is tagged sun or moon based on its first significant consonant, with the letter shown. 3. Apply to pronunciation: Sun-letter words double the consonant after al-; moon-letter words keep the lam audible. FAQ: Q: What are sun and moon letters? A: When the Arabic definite article ال (al-) attaches to a noun, the lam either assimilates or stays. The 14 sun letters cause the lam to assimilate so the following consonant doubles, as in ash-shams (the sun). The 14 moon letters leave the lam pronounced, as in al-qamar (the moon). The names come from these two example words. Q: Which letters are sun letters? A: The 14 sun letters are ت ث د ذ ر ز س ش ص ض ط ظ ل ن. They are mostly the coronal consonants, pronounced near where the tongue touches for lam, which is why assimilation is natural. The remaining 14 letters are moon letters. Q: How does the tool find the right letter? A: For each word it strips vowel marks and skips a leading definite article ال, then takes the first remaining consonant. That consonant determines whether the word is sun or moon, since assimilation is governed by the letter the article attaches to, not the alif-lam itself. Q: Does spelling change for sun letters? A: No. The lam is still written in both cases; only the pronunciation changes. In fully vowelled text a sun letter takes a shadda (doubling mark) and the lam loses its vowel, but the alif-lam is always spelled. This tool classifies by pronunciation, not by adding marks. Q: Is my text kept private? A: Yes. Classification happens entirely in your browser by comparing the leading letter against the sun and moon letter sets. Nothing you enter is uploaded, logged, or stored. #### Arabic RTL Direction Fixer URL: https://geratools.com/arabic-rtl-direction-fixer Fix scrambled Arabic that renders backwards in left-to-right apps by wrapping it in the correct Unicode bidi controls — RLI isolates, FSI, RLE embedding, or RLM marks. Copy the corrected snippet straight from your browser. How to use: 1. Paste the misbehaving snippet: Drop in the Arabic text that renders in the wrong order when placed inside a left-to-right interface, label, or code comment. 2. Choose a wrapping method: Pick an RTL isolate (recommended), a first-strong isolate, legacy RTL embedding, or lightweight RLM bracketing depending on where the text will live. 3. Copy the wrapped result: The output now carries the invisible control characters. A live preview in a left-to-right box shows that it reads correctly. FAQ: Q: Why does my Arabic text appear backwards? A: Software lays out text using the Unicode bidirectional algorithm. Inside a left-to-right context, an Arabic run mixed with digits, punctuation, or Latin words can be reordered incorrectly because the surrounding weak and neutral characters resolve to the wrong direction. Wrapping the run in an explicit RTL control forces the right order. Q: What is the difference between an isolate and an embedding? A: An isolate (RLI…PDI or FSI…PDI) sets the direction for its contents while hiding them from the surrounding bidi calculation, so it cannot leak into neighbouring text. The older embedding (RLE…PDF) sets direction but still participates in the outer context. Isolates are the modern recommendation. Q: When should I use plain RLM marks? A: The right-to-left mark (RLM) is an invisible zero-width character that nudges adjacent neutral characters to resolve as RTL. Bracketing a snippet with RLM on both sides is the lightest-weight fix and is handy when you only need to correct trailing punctuation, but full isolates are more robust for mixed content. Q: Will these characters show up visibly? A: No. All of the controls — RLM, RLE, PDF, RLI, FSI, PDI — are zero-width and invisible. They affect ordering only. The visible characters of your text are unchanged; the snippet just renders in the correct direction. Q: Does the tool send my text anywhere? A: No. It simply prepends and appends Unicode control characters in your browser. Nothing is uploaded, and the copy button puts the result, controls included, onto your clipboard. #### Bengali Conjunct Consonant Reference URL: https://geratools.com/bengali-conjunct-reference Shows the most common Bengali conjunct consonant clusters (যুক্তাক্ষর) formed via hasanta with their component letters, standard pronunciations, and example words. How to use: 1. Search the cluster: Type a component letter, a romanisation, or part of an example word to filter the table. 2. Read the breakdown: Each row shows the conjunct glyph, the consonants that combine to form it, and how it is pronounced. 3. Copy a conjunct: Click any conjunct glyph to copy it to your clipboard for use in documents or study notes. FAQ: Q: What is a Bengali conjunct? A: A conjunct (যুক্তাক্ষর, juktakkhor) is a ligature formed when two or more consonants meet with no vowel between them. The hasanta (virama, ্) suppresses the inherent vowel of the first consonant so the next attaches directly, often producing a fused shape. Q: How is a conjunct typed in Unicode? A: You type the first consonant, then the hasanta (U+09CD ্), then the second consonant. The font's shaping engine renders the fused ligature automatically. For example ক + ্ + ত produces ক্ত (kta). Q: Why do some conjuncts look nothing like their parts? A: Many Bengali conjuncts are fully fused ligatures rather than stacked letters. ক্ষ (kṣa) and জ্ঞ (jña) are classic examples — their visual form gives little hint of the ক+ষ and জ+ঞ that compose them, so they must be learned. Q: What is the ya-phala and ra-phala? A: When য (ya) is the second member it becomes a subscript called ya-phala (্য), and র (ra) as a second member becomes ra-phala (্র), a small hook below. These two are extremely common in Bengali spelling. Q: Is my input uploaded? A: No. The reference and its search run entirely in your browser. Nothing you type or copy leaves your device. #### Chinese Pinyin Annotator URL: https://geratools.com/chinese-pinyin-annotator Free pinyin annotator: paste Simplified Chinese and get tone-marked pinyin rendered as HTML ruby text above each character, ideal for learners, teachers and subtitles. Runs entirely in your browser. How to use: 1. Paste your Simplified Chinese text: Type or paste any Simplified Chinese passage into the input box. The annotator processes each character as you type. 2. Read the ruby output: Each recognised character shows its pinyin with tone marks rendered directly above it using HTML ruby markup, just like a learner textbook. 3. Check the coverage note: The tool reports how many characters matched its built-in dictionary so you know which words still need a manual reading. FAQ: Q: What is pinyin and what do the tone marks mean? A: Pinyin is the official romanisation of Mandarin Chinese. The diacritics show the four tones: flat (mā), rising (má), dipping (mǎ) and falling (mà). A character with no mark is read in the neutral tone. Tones change meaning, so they are essential for learners. Q: Why do some characters appear without pinyin? A: The tool uses a built-in dictionary of high-frequency characters. Rare or specialised characters that are not in the table are shown as-is without a reading. The coverage counter tells you exactly how many were matched so you can fill in the gaps manually. Q: How does it handle characters with more than one reading? A: Many Chinese characters are heteronyms with several valid pronunciations depending on context, such as 行 (xíng vs háng). This tool renders the single most common reading for each character. For ambiguous words you should verify the context-correct reading. Q: Does my text get uploaded anywhere? A: No. All annotation happens locally in your browser using JavaScript. Nothing you type is sent to a server, which makes the tool safe for private documents and works offline once the page has loaded. Q: Can I use the output in a document? A: The annotated text uses standard HTML ruby tags, which display correctly in modern browsers, e-readers and many word processors. You can copy the rendered region into rich-text editors that preserve ruby formatting. #### Chinese Date in Words URL: https://geratools.com/chinese-simplified-date-in-words Free Chinese date-in-words tool. Formats any Gregorian date as full Simplified Chinese prose using year/month/day 年月日 conventions, reading the year digit-by-digit and adding the correct 星期 weekday. Runs in your browser. How to use: 1. Pick a date: Use the date field to choose any Gregorian (solar) calendar date. 2. Read the Chinese prose: The tool spells out the date in full Simplified Chinese, with the year read digit-by-digit and the month and day as cardinal numbers ending in 月 and 日. 3. Copy the result: Click copy to place the formatted Chinese date, including the weekday, on your clipboard. FAQ: Q: Why is the year read digit-by-digit? A: Chinese reads calendar years one digit at a time, so 2026 is written 二〇二六年, not 两千零二十六年. The tool follows this convention, mapping each digit to its character including 〇 for zero. Q: How are the month and day written? A: Unlike the year, the month and day use ordinary cardinal numbers. December is 十二月 and the 25th is 二十五日. Numbers from 10 to 19 use the leading-十 shorthand, so the 15th is 十五日. Q: How is the weekday shown? A: The weekday uses 星期 followed by a number, where Monday is 星期一 through Saturday 星期六. Sunday is the special case 星期日 rather than 星期七. The tool computes the weekday from the date you choose. Q: Does this convert to the Chinese lunar calendar? A: No. This tool formats Gregorian (solar) dates into Chinese prose. Converting a solar date to the traditional lunar calendar is a separate astronomical calculation and is not performed here. Q: Does the date stay private? A: Yes. All formatting runs locally in your browser using JavaScript, with no server calls. The tool works offline once loaded and never transmits the date you select. #### Simplified to Traditional Chinese Converter URL: https://geratools.com/chinese-simplified-to-traditional Free Simplified to Traditional Chinese converter. Maps Simplified characters to their Traditional equivalents instantly using an OpenCC-derived table, with a count of how many characters changed. Runs entirely in your browser. How to use: 1. Paste Simplified Chinese text: Enter or paste any Simplified Chinese passage into the input box. Conversion happens live as you type. 2. Read the Traditional output: Each Simplified character is replaced by its Traditional equivalent, while shared characters and punctuation pass through unchanged. 3. Copy the result: Click the copy button to place the Traditional text on your clipboard, ready to paste into documents or messages. FAQ: Q: What is the difference between Simplified and Traditional Chinese? A: Simplified characters were standardised in mainland China in the 1950s to reduce stroke counts, while Traditional characters remain in use in Taiwan, Hong Kong and Macau. The two scripts share most characters, but several hundred have distinct forms, such as 国 (Simplified) versus 國 (Traditional). Q: Is this a true word-level conversion? A: No. This tool performs a character-by-character substitution using an OpenCC-derived table. It does not handle phrase-level regional vocabulary differences, for example 软件 converting to 軟件 rather than the Taiwan term 軟體. For publication-grade output, review region-specific word choices afterwards. Q: Why are some characters unchanged? A: Most Chinese characters are identical in both scripts, so only the characters that genuinely differ are substituted. Punctuation, numbers and Latin text always pass through untouched. The tool shows a count of how many characters were actually changed. Q: Does this work offline and keep my text private? A: Yes. The conversion table is embedded in the page and all processing runs in your browser with JavaScript. No text is uploaded, so the tool works offline once loaded and is safe for confidential material. Q: Can one Simplified character map to several Traditional ones? A: Occasionally. A few Simplified characters merged what were originally distinct Traditional characters, so the correct Traditional form can depend on meaning. This converter picks the most common mapping; verify ambiguous cases such as 发 (髮 hair versus 發 to send) by context. #### Traditional Chinese Pinyin Annotator URL: https://geratools.com/chinese-traditional-pinyin-annotator Annotate Traditional Chinese text with phonetic readings above each character, choosing zhuyin fuhao (bopomofo) for Taiwan learners or Hanyu Pinyin. Renders standard HTML ruby markup you can copy into a page, all in your browser. How to use: 1. Paste Traditional Chinese text: Drop your sentence or paragraph into the input box. 2. Choose zhuyin or pinyin: Pick zhuyin fuhao (bopomofo) for Taiwan-style annotation or Hanyu Pinyin with tone marks. 3. Copy the result: View the annotated preview and copy the generated HTML ruby markup for use on your own page. FAQ: Q: What is zhuyin fuhao? A: Zhuyin fuhao, commonly called bopomofo after its first four symbols, is the phonetic system taught in Taiwan. It writes each syllable with consonant and vowel symbols plus a tone mark, and is the standard way learners annotate Traditional Chinese. Q: Does it cover every character? A: It uses a built-in lookup table of common characters. Many Chinese characters have multiple readings depending on context, so rare or polyphonic characters may be left unannotated or show the most frequent reading. Always proofread important text. Q: What is HTML ruby markup? A: Ruby is the standard HTML element for placing small annotation text above base text. The tool wraps each character in a ruby element with an rt for the reading, which browsers render as the phonetic guide sitting above the character. Q: Why might a reading be wrong? A: Chinese has polyphonic characters whose pronunciation changes with the word, such as 行 (xíng vs háng). A character-by-character lookup cannot resolve this from context, so it shows the most common reading. Manual correction may be needed. Q: Is my text uploaded? A: No. Annotation is performed locally in your browser using a built-in table. Nothing you paste is sent to a server. #### Cyrillic Lookalike Converter URL: https://geratools.com/cyrillic-lookalike Free Cyrillic homoglyph converter. Replace Latin letters with visually identical Cyrillic characters to demonstrate and understand homoglyph and IDN spoofing attacks. Counts how many characters were swapped. Runs in your browser. How to use: 1. Type Latin text: Enter the Latin text or domain you want to convert in the input box. 2. See the lookalike: Each Latin letter that has a near-identical Cyrillic homoglyph is swapped, and a counter shows how many characters changed. 3. Copy and inspect: Click Copy to grab the result, then paste it into a hex or Unicode inspector to confirm the code points differ from plain Latin. FAQ: Q: What is a homoglyph? A: A homoglyph is a character from one script that looks identical, or nearly identical, to a character from another. The Cyrillic а (U+0430) and the Latin a (U+0061) render the same in most fonts but are completely different code points, which is what makes them useful for spoofing and confusing for security. Q: How is this used in attacks? A: Attackers register internationalised domain names (IDNs) or display names that swap Latin letters for Cyrillic lookalikes — for example a fake paypal.com where the a and p are Cyrillic. The text looks legitimate to a human but points somewhere else. Showing the swap here helps people recognise and defend against it. Q: Which letters get replaced? A: Only Latin letters with a genuinely convincing Cyrillic match are swapped — such as a, c, e, i, o, p, s, x, y and several capitals like A, B, E, H, K, M, O, P, T, X. Letters with no close Cyrillic equivalent are left as Latin so the output stays readable. Q: Is it safe and legal to use this? A: The tool itself is a harmless converter for education, security awareness, and detection. Using homoglyph text to impersonate brands, deceive users, or commit fraud is illegal in most jurisdictions. Use it to understand and defend against spoofing, not to carry it out. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser with JavaScript. Nothing you type is sent to a server, logged, or stored. #### English Plural Helper URL: https://geratools.com/english-plural-helper Pluralises any English noun using the real spelling rules for -s, -es, -ies, and -ves endings, plus a built-in list of irregular plurals like child to children and mouse to mice, with the rule shown. How to use: 1. Type a singular noun: Enter one English noun, such as child, knife, city, bus, or potato. 2. Read the plural: The correct plural form appears instantly, with capitalisation preserved if you capitalised the input. 3. Check the rule: The tool names the rule it applied, such as "Consonant + y to -ies" or "Irregular plural", so you can learn the pattern. FAQ: Q: How are -y endings handled? A: A noun ending in a consonant plus y changes y to -ies, so city becomes cities. A noun ending in a vowel plus y just adds s, so day becomes days and boy becomes boys. Q: When does -f become -ves? A: A specific set of nouns ending in -f or -fe change to -ves, such as knife to knives, wolf to wolves, and leaf to leaves. Many others simply add s, like roof to roofs, so the tool uses a known list rather than guessing. Q: Which words stay the same in the plural? A: Some nouns are identical in singular and plural, including sheep, deer, fish, series, and species. The tool recognises these and returns the word unchanged. Q: How complete is the irregular list? A: It covers the most common irregulars across everyday and academic English, including child/children, person/people, foot/feet, analysis/analyses, and datum/data. Rare or domain-specific irregulars may still need a dictionary check. Q: Does it know which words take -es? A: Yes. Nouns ending in a sibilant sound — s, x, z, ch, or sh — take -es, so box becomes boxes and church becomes churches. A short list of -o nouns like potato and hero also take -es. #### Finnish Currency in Words URL: https://geratools.com/finnish-currency-words Writes euro amounts as Finnish words, building the single closed-compound number form and using the partitive case euroa and senttiä for any amount other than exactly one. Runs entirely in your browser. How to use: 1. Enter the amount: Type a euro amount such as 1234,56 using a comma for the decimal. The value is parsed in your browser. 2. Read the Finnish form: The tool builds the closed-compound Finnish words for the euros and cents and joins them with "ja". 3. Copy for your document: Copy the spelled-out amount into an invoice, contract, or cheque where a words form is required. FAQ: Q: Why is the amount written as one long word? A: Finnish writes numbers below a million as a single closed compound, so 234 is kaksisataakolmekymmentäneljä with no spaces. Spaces appear only around the scale words tuhat (thousand) and miljoona (million), which is standard Finnish orthography. Q: What is the partitive case used for here? A: After any cardinal number other than exactly one, the counted noun takes the partitive case: 1 euro but 2 euroa, 1 sentti but 56 senttiä. The tool applies euroa and senttiä automatically unless the count is exactly one. Q: How are the cents formed? A: The fractional part is rounded to two decimal places as the cent count and spelled out in full Finnish words, then suffixed with senttiä (or sentti for exactly one). The euros and cents are joined with the word ja (and). Q: How do I write the leading one in hundreds and thousands? A: Finnish drops the multiplier one before the scale word, so 100 is sata not yksisata and 1000 is tuhat not yksituhatta. The tool follows this rule while still saying yksi euro for a single euro. Q: Is my amount sent to a server? A: No. The number-to-words logic is bundled into the page and runs entirely in your browser, so confidential figures never leave your device. Nothing about the amount you type is uploaded. Q: When is the multiplier yksi dropped? A: Only directly before the scale words sata (hundred), tuhat (thousand), and miljoona (million): 100 is sata, 1000 is tuhat, 1000000 is miljoona. The yksi is kept everywhere else — one euro is yksi euro, and 21 is kaksikymmentäyksi with the units yksi intact. Q: Why does 1 234 have a space but 234 does not? A: Finnish writes numbers below a thousand as a single closed compound with no internal spaces (234 = kaksisataakolmekymmentäneljä). Spaces appear only around the scale words tuhat and miljoona, so 1 234 becomes 'tuhat kaksisataakolmekymmentäneljä' — one space after tuhat, none inside the hundreds group. #### Greek Lookalike Converter URL: https://geratools.com/greek-lookalike Free Greek homoglyph converter. Replace Latin letters with visually similar Greek characters (alpha, beta, rho, chi) for stylistic text or to understand homoglyph spoofing. Counts swapped characters. Runs in your browser. How to use: 1. Type Latin text: Enter the Latin text you want to convert in the input box. 2. See the Greek version: Each Latin letter with a similar Greek counterpart is swapped, and a counter shows how many characters changed. 3. Copy the result: Click Copy to grab the Greek-styled text and paste it where Unicode is supported. FAQ: Q: How close are Greek characters to Latin letters? A: Greek letterforms are similar but generally less identical than Cyrillic. Some are very convincing — α for a, ο for o, ρ for p, χ for x — while others such as η for n or γ for y are looser, stylistic matches. That is why this is described as a lookalike rather than a perfect homoglyph swap. Q: What is a homoglyph and why does it matter? A: A homoglyph is a character that looks like one from another script but is a different code point. Greek ο (U+03BF) and Latin o (U+006F) look the same yet differ in encoding. Attackers exploit this in spoofed names and domains, so recognising mixed-script text is a useful security skill. Q: Which letters are replaced? A: Letters with a reasonable Greek equivalent are swapped — a, b, e, i, k, n, o, p, u, v, w, x, y and capitals like A, B, E, H, K, M, N, O, P, T, X, Y, Z. Letters with no decent Greek lookalike are left as Latin so the text stays readable. Q: Can I use this for fonts or branding? A: You can use it for decorative, mythology-themed, or stylistic text where the Greek look is the point. Avoid using it to impersonate real brands or domains — using confusable characters to deceive is illegal in most jurisdictions. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser with JavaScript. Nothing you type is sent to a server, logged, or stored. #### Greek Numeral System Converter URL: https://geratools.com/greek-numerals Encode integers using the Milesian Greek alphabetic numeral system, with the special letters stigma for 6, koppa for 90 and sampi for 900, plus the keraia marks used for numbers above 999. Runs in your browser. How to use: 1. Enter an integer: Type a whole number. The Milesian system covers 1 upward, with a keraia prefix used for the thousands. 2. Read the Greek numeral: The number is broken into thousands, hundreds, tens and units and each part is shown with its alphabetic letter and the keraia mark. 3. Copy the result: Use the copy button to paste the numeral into manuscripts, classics study notes, or typography work. FAQ: Q: What is the Milesian or alphabetic numeral system? A: It is the classical Greek way of writing numbers using the 24 letters of the alphabet plus three archaic letters. Alpha through theta cover 1 to 9, iota through koppa cover the tens, and rho through sampi cover the hundreds. Q: What are stigma, koppa and sampi? A: They are three letters retained only as numerals: stigma is 6, koppa is 90 and sampi is 900. The Greek alphabet alone has 24 letters, so these three fill the gaps needed to reach 27 numeral symbols for units, tens and hundreds. Q: How are thousands written? A: Thousands from 1000 to 9000 reuse the unit letters alpha to theta but with a keraia mark, a small stroke, placed before and below the letter. This tool prefixes the thousands letters with the lower keraia character. Q: Is a keraia added to ordinary numerals? A: Yes. In manuscripts a keraia, an upper stroke, often follows a numeral to mark it as a number rather than a word. This tool appends the upper keraia to the units-tens-hundreds group. Q: What is the largest supported number? A: The standard alphabetic system reaches 9999 cleanly using the keraia for thousands. Above that, scribes used the myriad letter M with multipliers, which this tool does not encode; it accepts 1 to 9999. #### Greek Romanization URL: https://geratools.com/greek-transliteration Romanize modern Greek into Latin script under ELOT 743 (the official Greek/UN standard), ISO 843 transliteration, or a phonetic transcription. Handles digraphs like ου, μπ, ντ and context rules for γγ, γκ, and αυ/ευ. How to use: 1. Enter Greek text: Type or paste the modern Greek word, name, or sentence to romanize. 2. Pick a scheme: Choose ELOT 743 (official), ISO 843, or phonetic, depending on whether you need passport-style, library-style, or sound-based output. 3. Copy the result: Read the Latin-script output and copy it for documents, URLs, or citations. FAQ: Q: What is ELOT 743? A: ELOT 743 is the official Greek standard for romanizing Greek into Latin letters, also adopted by the UN. It is used on Greek passports and road signs. It transliterates most letters directly, for example η→i, υ→y, and ου→ou. Q: How does ELOT 743 differ from ISO 843? A: ISO 843 is the international transliteration standard and uses diacritics to keep a reversible one-to-one mapping, for example ē for η and ō for ω. ELOT 743 favours plain Latin letters without diacritics, which is friendlier for everyday use and passports. Q: What does phonetic mode do? A: Phonetic mode approximates how the Greek sounds in modern pronunciation. It renders context-sensitive groups such as μπ as b, ντ as d, γκ as g, and αυ/ευ as av/ev or af/ef depending on the following sound. Q: Why do some letters depend on context? A: Greek has combinations whose sound changes with neighbours: γγ and γκ are 'ng/g', αυ is 'av' before voiced sounds but 'af' before voiceless ones, and final or initial position can matter. The tool applies these rules so the output reads correctly. Q: Is the conversion exact? A: ELOT 743 and ISO 843 are deterministic standards and the tool follows their letter tables closely. Phonetic transcription is an approximation, since real pronunciation has subtleties no single mapping captures perfectly. Q: Why does αυ sometimes become 'av' and sometimes 'af'? A: The υ in αυ is a consonant sound whose voicing follows the next letter. It becomes 'v' before a voiced sound (vowels and β, γ, δ, ζ, λ, μ, ν, ρ) and 'f' before a voiceless one (θ, κ, ξ, π, σ, τ, φ, χ, ψ) or at word end. So αυτό → afto but αύριο → avrio. Q: Which scheme should I use for a passport or airline booking? A: ELOT 743. It is the standard used on Greek passports and avoids diacritics, so it passes through Latin-only forms and travel systems cleanly. ISO 843's accented characters (ē, ō) are often stripped or rejected by booking systems, so never use it for identity or travel data. #### Hebrew Aleph-Bet Script Reference URL: https://geratools.com/hebrew-aleph-bet-reference A filterable reference of all 22 Hebrew alphabet letters with name, print glyph, final (sofit) form, gematria numeric value, and transliteration. Includes the five sofit letters and standard gematria values. Runs in your browser. How to use: 1. Browse the letter table: Scan all 22 Hebrew letters with their names, glyphs, and gematria values. 2. Filter to a letter: Type a letter name, sound, or number to narrow the table. 3. Copy a glyph: Click any row to copy that Hebrew letter to your clipboard. FAQ: Q: How many letters are in the Hebrew alphabet? A: There are 22 letters, all consonants, written from right to left. Vowels are normally added as small marks (nikud) beneath or beside the letters, but the base aleph-bet itself is the 22 consonant signs shown here. Q: What are the final (sofit) forms? A: Five letters change shape when they fall at the end of a word: kaf, mem, nun, pe, and tsadi. These final forms are called sofit and are shown in the Final column. The gematria value is the same as the regular form. Q: What is gematria? A: Gematria assigns each Hebrew letter a number: aleph to tet are 1 to 9, yod to tsadi are 10 to 90, and qof to tav are 100 to 400. Adding the values of a word's letters gives its numeric value, a technique used in Jewish textual interpretation. Q: Why do some letters list two sounds? A: Letters like bet, kaf, and pe have a hard and a soft pronunciation depending on a dot called dagesh. Bet is b or v, kaf is k or kh, and pe is p or f. Shin is sh or s depending on which side its dot sits. Q: Does anything leave my browser? A: No. The table and filtering run entirely in your browser. Nothing you type is uploaded or stored. #### Hebrew Binyanim Reference URL: https://geratools.com/hebrew-binyanim-reference Explains all seven Hebrew binyanim (Pa'al, Nif'al, Pi'el, Pu'al, Hitpa'el, Hif'il, Huf'al) with their voice, typical meaning, the root template, and an example verb built on the root k-t-v so you can compare patterns side by side. How to use: 1. Enter a three-letter root: Type the three root consonants transliterated, such as k-t-v for the writing root, to slot into each pattern. 2. Scan the seven patterns: Each binyan row shows its name, grammatical voice, typical meaning, and the third-person masculine singular past form for your root. 3. Pick the right binyan: Use the meaning column to choose which binyan expresses what you want — active, passive, reflexive, intensive, or causative. FAQ: Q: What are the binyanim? A: The binyanim (literally buildings) are the seven verb patterns or conjugation templates of Hebrew. Every verb root is conjugated through one or more binyanim, each adding a layer of meaning such as passive, causative, or reflexive on top of the basic action carried by the three-consonant root. Q: Are all seven binyanim used for every root? A: No. Most roots appear in only a few of the seven binyanim. The pattern that a given root uses, and the precise meaning it carries there, is partly lexicalized and must be learned per root rather than fully predicted from the template. Q: How do active and passive binyanim pair up? A: Three pairs relate active to passive: Pa'al's passive is Nif'al, Pi'el pairs with Pu'al, and Hif'il pairs with Huf'al. Pu'al and Huf'al are almost always passive and rarely appear in the imperative or infinitive. Hitpa'el stands apart as the reflexive/reciprocal pattern. Q: What does the vowel pattern do? A: Each binyan imposes a fixed vowel pattern and sometimes prefixes (ni-, hit-, hi-) or a doubled middle consonant (Pi'el, Pu'al, Hitpa'el). Slotting the same three root letters into different vowel-and-affix templates produces the different binyanim, which is why they share a root but differ in shape and sense. Q: Why is the example verb in the third masculine singular past? A: The third-person masculine singular of the past tense is the citation form of a Hebrew verb, the way an English verb is cited by its infinitive. Showing each binyan in that form lets you compare the seven templates on equal footing using one familiar slot. #### Hebrew RTL Direction Fixer URL: https://geratools.com/hebrew-rtl-direction-fixer Wrap Hebrew runs in mixed Hebrew-English text with the correct Unicode bidi control characters (RLI/PDI isolates, RLE/PDF embeddings, or RLM marks) so they display in the right order inside LTR HTML, code, and documents. Free and private. How to use: 1. Paste mixed-direction text: Enter text that mixes Hebrew (or Arabic) with Latin script or numbers. 2. Pick a bidi strategy: Choose isolates (recommended), legacy embeddings, or lightweight RLM marks depending on where the text will live. 3. Copy the fixed text: Copy the corrected text, or copy the escaped version to see exactly which invisible markers were inserted. FAQ: Q: Why does Hebrew display in the wrong order in English text? A: The Unicode Bidirectional Algorithm guesses direction from surrounding context. In a left-to-right paragraph, an embedded Hebrew run plus adjacent numbers or punctuation can be reordered incorrectly. Explicit bidi control characters tell the renderer exactly where the right-to-left run starts and ends. Q: What is the difference between isolates and embeddings? A: Isolates (RLI U+2067 to PDI U+2069) are the modern recommendation: they set direction without letting the run affect the ordering of text around it. Embeddings (RLE U+202B to PDF U+202C) are the older mechanism and can have side effects on neighbouring characters, so prefer isolates unless you need legacy support. Q: When should I use the RLM marks option? A: Right-to-Left Marks (U+200F) are a lightweight fix that nudges direction at a single point without wrapping a whole run. They are useful in places where you cannot insert paired controls, such as some plain-text fields, though they are less robust than isolates for longer runs. Q: The output looks identical to the input. Did it work? A: Yes. Bidi control characters are invisible by design, so the copied text looks the same but carries hidden markers. Use the escaped view to confirm the markers are present; it shows each control character as its \uXXXX code so you can verify placement. Q: Is my text processed locally? A: Yes. The marker insertion runs entirely in your browser. No text is uploaded, so your content stays private on your device. #### Hindi Currency in Words URL: https://geratools.com/hindi-currency-in-words Free tool that spells Indian rupee amounts in Hindi prose (रुपये and पैसे) using the lakh and crore scale, formatted for cheques and legal documents. Runs entirely in your browser. How to use: 1. Enter the amount: Type the rupee amount, including paise after a decimal point if needed. 2. Read the Hindi prose: The amount appears spelled out in Hindi with रुपये and पैसे below. 3. Copy for your cheque: Use the Copy button to paste the wording onto a cheque or document. FAQ: Q: How are paise handled? A: Paise are the 1/100 subunit of a rupee. The tool reads up to two decimal digits as paise and spells them after the rupee part, joined by और, for example एक हज़ार रुपये और पचहत्तर पैसे. Q: What numbering scale does it use? A: It uses the Indian system of lakhs and crores, so 1,25,000 is read as एक लाख पच्चीस हज़ार रुपये rather than the Western hundred-thousand grouping. Q: Why does the result end with मात्र? A: मात्र means 'only' and is the conventional closing word on Indian cheques and legal amounts, preventing anyone from appending extra digits to the written amount. Q: Can I include currency symbols or commas in the input? A: Yes. The tool strips the ₹ symbol, commas and spaces before parsing, so 1,250.75 and ₹1250.75 both work. Q: Is my amount uploaded? A: No. The conversion runs entirely in your browser, so the figures you enter never leave your device. #### Hindi IPA Transcription Tool URL: https://geratools.com/hindi-ipa-transcriber Convert Devanagari Hindi to IPA in your browser, marking the full aspirated/unaspirated and dental/retroflex distinctions, nasalisation, the inherent schwa with schwa deletion, and the nukta consonants. How to use: 1. Paste Devanagari: Enter Hindi text in Devanagari script. The tool reads consonants, vowel signs (matras), and modifiers directly. 2. Read the IPA: Consonants carry the inherent schwa /ə/ unless a virama or matra overrides it, and aspiration and retroflexion are marked explicitly. 3. Check the contrasts: Verify that क/ख give /k/ vs /kʰ/ and त/ट give the dental /t̪/ vs retroflex /ʈ/, the contrasts Hindi depends on. FAQ: Q: How is the inherent schwa handled? A: Every bare consonant in Devanagari carries an inherent /ə/. The tool adds /ə/ after each consonant unless a vowel sign (matra), a virama (्), or word-final schwa-deletion context overrides it. Q: What is schwa deletion? A: Hindi deletes the final inherent schwa of most words, so कमल is /kəməl/ not /kəmələ/. The tool applies a word-final schwa-deletion heuristic; medial schwa deletion is more complex and left intact. Q: How are retroflex consonants shown? A: ट ठ ड ढ ण are retroflex and surface as /ʈ ʈʰ ɖ ɖʰ ɳ/ with the retroflex hook, distinct from the dental /t̪ t̪ʰ d̪ d̪ʰ n/ of त थ द ध न. Q: Does it handle the nukta letters? A: Yes. Nukta consonants क़ ख़ ग़ ज़ फ़ ड़ ढ़ map to /q χ ɣ z f ɽ ɽʰ/, the Perso-Arabic and flap sounds used in loanwords and many native words. #### Hindi IAST Transliteration URL: https://geratools.com/hindi-transliteration-iast Free Devanagari to IAST transliterator that applies the inherent-vowel and virama rules to convert Hindi script into the International Alphabet of Sanskrit Transliteration. Runs in your browser. How to use: 1. Paste Devanagari text: Type or paste the Hindi script you want to romanise. 2. Read the IAST output: The transliteration with diacritics appears instantly below. 3. Copy the result: Use the Copy button to paste the IAST text into academic documents. FAQ: Q: What is IAST? A: IAST is the International Alphabet of Sanskrit Transliteration, a diacritic-based Roman scheme used by scholars to represent Devanagari unambiguously. It distinguishes long and short vowels and retroflex consonants, for example ā, ī and ṭ. Q: How is the inherent vowel handled? A: Each Devanagari consonant carries an inherent short 'a'. The tool adds 'a' after a consonant unless a dependent vowel sign or the virama follows it, so क is ka while क् is just k. Q: Does it handle conjuncts and the virama correctly? A: Yes. The virama (्) suppresses the inherent vowel, so a consonant cluster like स्त transliterates as 'sta' rather than 'sata', preserving the conjunct. Q: Are nukta letters like ज़ supported? A: Yes. Nukta consonants used for Hindi and Urdu loan sounds are mapped — ज़ becomes z, फ़ becomes f and क़ becomes q — with input normalised so both spellings match. Q: Is my text sent to a server? A: No. The transliteration is computed entirely in your browser and the text is never uploaded. #### Japanese Full-Width / Half-Width Converter URL: https://geratools.com/japanese-fullwidth-halfwidth-converter Converts full-width ASCII letters, digits and punctuation (Ａ-Ｚ, ０-９) to half-width and back, with correct half-width katakana conversion including recombining dakuten and handakuten marks. How to use: 1. Choose a direction: Select full-width to half-width or half-width to full-width conversion. 2. Paste the text: Enter the Japanese text containing full-width or half-width characters. 3. Copy the result: Copy the converted output, optionally including half-width katakana conversion. FAQ: Q: What are full-width and half-width characters? A: Full-width (zenkaku) characters occupy the same square cell as a kanji, while half-width (hankaku) characters take half that width. Japanese text often mixes full-width Latin letters and digits with normal half-width ASCII, which causes inconsistent data. Q: How does the ASCII conversion work? A: Full-width ASCII lives in the Unicode block U+FF01 to U+FF5E, which sits exactly 0xFEE0 above the matching plain ASCII codes U+0021 to U+007E. Converting is a fixed code-point shift in either direction, with the full-width space U+3000 mapped to and from a normal space. Q: What about half-width katakana? A: When converting to full-width you can also map half-width katakana (U+FF61 to U+FF9F) to standard full-width katakana. The tool recombines a half-width dakuten or handakuten that follows a base kana, so ｶﾞ becomes ガ and ﾊﾟ becomes パ. Q: Why normalise width before storing data? A: Search, sorting, and de-duplication treat Ａ and A as different characters, so width inconsistency causes missed matches and duplicate records. Normalising ASCII to half-width and katakana to full-width gives a single canonical form for indexing. Q: Is my text uploaded? A: No. All conversion happens in your browser using code-point arithmetic and a built-in katakana table. Nothing you paste is sent to a server. #### Japanese Furigana Annotator URL: https://geratools.com/japanese-furigana-annotator Annotate Japanese kanji with hiragana furigana using a built-in kanji-to-reading table, generating standard HTML ruby markup you can copy into a page. Built for learners and editors, it runs entirely in your browser with no upload. How to use: 1. Paste Japanese text: Drop your sentence or paragraph containing kanji into the input box. 2. Let it annotate: Each recognized kanji is wrapped with its hiragana reading above it. 3. Copy the result: View the annotated preview and copy the generated HTML ruby markup for your page. FAQ: Q: What is furigana? A: Furigana are the small hiragana printed above or beside kanji to show how to read them. They are widely used in materials for learners and children, and on the web they are rendered with the HTML ruby element. Q: Does it read every kanji correctly? A: It uses a built-in table of common kanji and frequent compound words. Many kanji have multiple readings that depend on the word and context, so rare kanji may be left unannotated and ambiguous ones may show the most common reading. Always proofread important text. Q: How are compound words handled? A: The annotator first tries to match multi-kanji words from its dictionary, such as 日本 reading にほん, before falling back to single-kanji readings. This produces correct readings for common compounds that a character-by-character lookup would get wrong. Q: What markup does it produce? A: It produces standard HTML ruby: each annotated kanji or word is wrapped in a ruby element with an rt holding the hiragana reading. Browsers render the hiragana above the base text, and you can paste the markup straight into a page. Q: Is my text uploaded? A: No. Annotation runs locally in your browser using a built-in table. Nothing you paste is sent to a server. #### Japanese Honorific / Keigo Level Checker URL: https://geratools.com/japanese-honorific-helper Scan Japanese text for keigo honorifics and label each word as sonkeigo (respectful), kenjogo (humble) or teineigo (polite). A study aid for understanding politeness registers, running entirely in your browser. How to use: 1. Paste Japanese text: Enter any sentence or passage that may contain keigo vocabulary. 2. Read the labels: Each detected honorific is tagged sonkeigo, kenjogo or teineigo with its plain equivalent. 3. Compare the registers: Use the per-category counts to gauge how respectful, humble or merely polite the text is. FAQ: Q: What are the three types of keigo? A: Sonkeigo (尊敬語) is respectful language that elevates the listener or a third party, such as 召し上がる for eat. Kenjogo (謙譲語) is humble language that lowers the speaker, such as 参る for go. Teineigo (丁寧語) is plain politeness using です, ます and the o-/go- prefixes. Q: How does the checker identify keigo words? A: It matches the text against a curated lexicon of the most common honorific verbs and forms, using longest-match-first so that polite endings like 召し上がります are recognised over their shorter dictionary form. Each match shows its category and plain equivalent. Q: Why does the same word sometimes serve eating and drinking? A: Several keigo verbs cover multiple plain verbs. 召し上がる is the respectful form of both 食べる (eat) and 飲む (drink), while いただく is the humble counterpart for receiving, eating and drinking alike. The plain column lists all equivalents. Q: Does it catch every honorific in a sentence? A: It catches the common, irregular keigo verbs and the です/ます/ございます politeness markers. Productive patterns such as お + verb-stem + になる or passive-as-respect are not exhaustively matched, so treat it as a study aid rather than a grammar checker. Q: Is my text sent to a server? A: No. Matching happens entirely in your browser against a local word list, so nothing you paste is uploaded. #### Japanese IPA Transcription Tool URL: https://geratools.com/japanese-ipa-transcriber Convert Japanese kana to IPA in your browser, including the high central vowel /ɯ/ for す, the moraic nasal ɴ, palatalized yōon, geminate っ, and long vowels — all computed locally. How to use: 1. Paste kana: Enter hiragana or katakana. The tool reads both scripts and treats them identically for phonemic output. 2. Read the IPA: Each mora is mapped to its IPA form, with yōon, geminates, long vowels, and the moraic nasal resolved in context. 3. Verify the special cases: Check that す renders as /sɯ/, ふ as /ɸɯ/, ん as /ɴ/, and small っ as gemination of the next consonant. FAQ: Q: Why is す transcribed /sɯ/ and not /su/? A: Japanese /u/ is a high back unrounded (or compressed) vowel, written /ɯ/ in IPA, not the rounded /u/ of English. The tool uses /ɯ/ throughout for the う-row to reflect standard Tokyo Japanese. Q: How is the small っ (sokuon) handled? A: The geminate marker doubles the following consonant onset. っか becomes /kka/ and っぱ becomes /ppa/. Before a fricative it lengthens that fricative instead. Q: What does ん become? A: The moraic nasal ん is given as /ɴ/ in broad transcription. Its true place of articulation assimilates to the following sound, but the tool shows the underlying uvular /ɴ/ for a stable phonemic reading. Q: Does it mark pitch accent? A: No. The tool outputs segmental IPA only. Tokyo Japanese has a high/low pitch accent, but that is lexical and not predictable from kana, so it is left unmarked. #### Japanese JLPT Level Checker URL: https://geratools.com/japanese-jlpt-level-checker Free Japanese JLPT level checker. Paste Japanese text and the tool scans its kanji against representative N5–N1 lists and reports the highest JLPT level needed to read it, with a per-level breakdown. Runs in your browser. How to use: 1. Paste Japanese text: Drop any Japanese passage into the box. The tool scans every kanji and ignores kana and punctuation. 2. Read the estimated level: It reports the highest JLPT level any kanji reaches — that is the level a reader needs for the whole passage. 3. Review the breakdown: A per-level table shows how many kanji fall into N5 through N1, plus any beyond the lists, and lists the hardest kanji driving the result. FAQ: Q: How does the level estimate work? A: The JLPT runs from N5 (easiest) to N1 (hardest). The tool looks up each kanji's lowest JLPT band and reports the highest band reached by any kanji in your text, since a reader must know the hardest character to read the whole passage. Kanji found in no list are treated as beyond N1 (advanced). Q: Does it check vocabulary and grammar too? A: No. This is a kanji-based estimate only. The JLPT also tests vocabulary, grammar, listening, and reading speed, so a passage with simple kanji could still be hard for other reasons. Use the result as a quick reading-difficulty signal, not an official placement. Q: Why does kana-only text show no level? A: Hiragana and katakana are learned at the very beginning, so text with no kanji has no kanji to grade and is reported as N5 or below. The checker focuses on kanji because they are the main driver of reading difficulty across JLPT levels. Q: How complete are the kanji lists? A: The tool uses representative core kanji for each level rather than the full ~2,000-character official lists, focusing on the kanji behind the most common vocabulary. That keeps it fast and gives a realistic estimate for everyday text; very rare or proper-noun kanji may register as advanced (beyond N1). Q: Is my text uploaded? A: No. All scanning and lookups happen locally in your browser with JavaScript. Nothing is sent to a server, stored, or logged, so you can analyse private study material or documents safely. #### Japanese Romaji Converter URL: https://geratools.com/japanese-romaji-converter Convert Japanese kana to Latin letters in the three standard romanization schemes — Hepburn, Nihon-shiki, and Kunrei-shiki — with correct yōon, sokuon doubling, and long-vowel handling. Compare schemes side by side, all in your browser. How to use: 1. Paste kana text: Enter hiragana or katakana into the input box. 2. Pick a scheme: Choose Hepburn, Nihon-shiki, or Kunrei-shiki romanization. 3. Copy the result: Read the romaji output and copy it for documents, search, or transliteration. FAQ: Q: What is the difference between the three schemes? A: Hepburn writes sounds as English speakers hear them (し = shi, ち = chi, つ = tsu). Nihon-shiki is the most systematic, mapping each kana by its grid position (し = si, ぢ = di). Kunrei-shiki is the Japanese government and ISO 3602 standard, a near-merge of Nihon-shiki that simplifies a few pairs (し = si, ぢ = zi). Q: How is the small っ handled? A: The sokuon っ doubles the following consonant in all three schemes, so きって becomes kitte. Before ch in Hepburn it produces tch (まっちゃ = matcha), which is the standard Hepburn convention. Q: How are long vowels treated? A: The katakana long mark ー repeats the preceding vowel, so コーヒー becomes koohii. Hepburn often uses a macron in print, but this tool repeats the vowel so the output stays plain ASCII and reversible. Q: Does it handle yōon like きゃ? A: Yes. Combined kana such as きゃ, しゅ, ちょ are treated as single syllables and romanized accordingly — kya, shu, cho in Hepburn or kya, syu, tyo in Kunrei-shiki. The converter matches multi-character kana before single kana. Q: Is my text uploaded? A: No. Conversion runs entirely in your browser using built-in tables. Nothing you enter is sent to a server. #### Korean IPA Transcription Tool URL: https://geratools.com/korean-ipa-transcriber Convert Korean Hangul to IPA symbols in your browser, automatically applying Korean phonological rules such as nasalization, liquidization, aspiration, and palatalization across syllable boundaries. How to use: 1. Paste Korean text: Enter Hangul syllable blocks in the input box. Romanized text is not supported because the tool reads jamo directly. 2. Read the IPA output: The tool decomposes each syllable into onset, nucleus, and coda, then applies cross-syllable assimilation before printing the IPA. 3. Check the applied rules: A notes panel lists which sandhi rules fired (nasalization, liquidization, aspiration) so you can verify the result. FAQ: Q: Does it handle nasalization? A: Yes. When a stop coda such as /k t p/ meets a following nasal onset /n m/, the coda nasalizes to /ŋ n m/. The tool detects these boundaries and rewrites both consonants before producing IPA. Q: What about liquidization (ㄴ becoming ㄹ)? A: When /n/ and /l/ are adjacent in either order, both surface as the lateral /l/. This bidirectional rule is applied across the syllable boundary so words like 신라 transcribe with /ll/. Q: Why does some final /k/ become unreleased? A: Korean obstruent codas are unreleased, marked with the IPA no-audible-release diacritic. Before a vowel-initial particle, resyllabification moves the coda into the next onset instead. Q: Does it show pitch or stress? A: No. Standard Seoul Korean is not lexically tonal, so the tool gives a broad phonemic transcription of segments only and does not mark pitch accent or intonation. #### Korean Dubeolsik Keyboard Reference URL: https://geratools.com/korean-keyboard-reference Free Dubeolsik keyboard reference — see the standard Korean 두벌식 layout mapped onto a QWERTY keyboard, with each key's base and shifted jamo labelled, and a live key-to-jamo lookup, in your browser. How to use: 1. View the layout: The full Dubeolsik keyboard is drawn over QWERTY, with consonants on the left and vowels on the right. 2. Find a jamo: Type a Latin letter to highlight which Korean jamo it produces, unshifted and shifted. 3. Learn the doubles: Hold Shift on ㅂㅈㄷㄱㅅ to get the tense consonants ㅃㅉㄸㄲㅆ and ㅒ ㅖ for O and P. FAQ: Q: What is Dubeolsik? A: Dubeolsik (두벌식) is the standard two-set Korean keyboard layout used on virtually all computers and phones in South Korea. Consonants sit on the left half of the keyboard and vowels on the right, so syllables are typed left-to-right. Q: How do I type double consonants? A: The tense consonants ㅃ ㅉ ㄸ ㄲ ㅆ are typed by holding Shift on their plain counterparts ㅂ ㅈ ㄷ ㄱ ㅅ (keys Q W E R T). Shift also produces the bright vowels ㅒ and ㅖ on O and P. Q: Why are consonants and vowels separated? A: Hangul syllables are built consonant-then-vowel(-then-consonant). Putting consonants on the left hand and vowels on the right lets both hands alternate, which makes Korean typing fast and reduces same-finger repeats. Q: Does the layout match a US QWERTY board? A: Yes. Dubeolsik overlays the same physical QWERTY keys, so a US keyboard works perfectly — you just switch input language. This reference shows exactly which jamo each QWERTY key produces. Q: Is anything uploaded? A: No. The layout map and the key lookup run entirely in your browser, so nothing is sent to any server. #### Korean Large Number Formatter URL: https://geratools.com/korean-large-number-formatter Format a large integer using the Korean myriad system, which advances every four digits: 만 (10,000), 억 (100 million), 조 (1 trillion). Shows both the digit form (1억2345만) and Sino-Korean Hangul reading. Runs in your browser. How to use: 1. Enter a whole number: Type any positive integer, with or without commas, into the input box. 2. Read the myriad grouping: The number is shown with Korean 만, 억, and 조 unit markers placed every four digits. 3. Read the Hangul: The value is spelled out in Sino-Korean numerals, dropping 일 before 십, 백, and 천 as Korean convention requires. FAQ: Q: Why do Korean units advance every four digits? A: Korean uses a myriad system shared with Chinese and Japanese, where each unit is 10,000 times the last: 만 is 10,000, 억 is 100 million, and 조 is one trillion. Western grouping every three digits does not match this. Q: What does the digit form like 1억2345만6789 mean? A: It keeps Arabic digits but inserts Korean unit markers at each myriad boundary, a compact mixed notation common in Korean finance and news for reading large figures quickly. Q: Why is 일 sometimes dropped? A: In standard Sino-Korean counting, 일 is omitted before 십, 백, and 천, so 1,000 is written 천 rather than 일천. The tool follows this so the Hangul reads naturally. Q: How large a number can it handle? A: It supports values up to the 경 (10 quadrillion) range within JavaScript's safe-integer limit. Numbers beyond that are reported rather than mis-formatted. Q: Is my input sent to a server? A: No. The conversion runs entirely in your browser with JavaScript, so the number you enter is never uploaded or stored. #### Korean Archaic/Old Hangul Reference URL: https://geratools.com/korean-old-hangul-reference Shows obsolete Korean jamo (ㆍ araea, ㅿ bansiot, ㆆ yeorinhieut, ㆁ old ieung and more) found in classical texts, with their names, Unicode code points and historical pronunciation, plus a text scanner. How to use: 1. Browse or search: Type a jamo name, its Korean name, or a sound to filter the reference table. 2. Read the entry: Each obsolete letter shows its name, Unicode code point, historical sound, and where it occurs. 3. Scan your text: Paste a classical passage into the scanner to list any obsolete jamo it contains. FAQ: Q: What is old or archaic Hangul? A: Old Hangul refers to letters that were part of the original 1443 alphabet created under King Sejong but later fell out of use as the sounds they represented merged or disappeared. They appear in classical texts such as the Hunminjeongeum and in some dialect writing. Q: What is araea (ㆍ)? A: Araea, also called the lower dot, was a vowel pronounced as a low back sound between modern a and o. It merged into ㅏ and ㅡ by the eighteenth century but survives in Jeju dialect and in stylised names like Hangeul Day. Q: Why did these letters disappear? A: Each obsolete jamo marked a distinction in pronunciation that Korean later lost. For example ㅿ stood for a voiced z that merged into ㅅ or silence, and ㆁ marked an initial ng that merged with the silent ieung ㅇ, so the separate letters became unnecessary. Q: Can I still type these characters? A: Yes. They have Unicode code points in the Hangul Compatibility Jamo block, shown in the table, so they render in fonts that support old Hangul. They are used today mainly in scholarship, dictionaries, and dialect transcription rather than everyday writing. Q: Is my text uploaded? A: No. The reference data is bundled with the page and the scanner runs entirely in your browser. Nothing you paste is sent to a server. #### Korean Particle (조사) Reference URL: https://geratools.com/korean-particle-reference Lists the major Korean postpositional particles with their grammatical role and the consonant-final versus vowel-final alternant (은/는, 이/가, 을/를, 와/과, 으로/로), and picks the correct form for any Korean noun you enter. How to use: 1. Enter a Korean noun: Type a noun in Hangul; the tool checks whether its last syllable ends in a consonant (받침) or a vowel. 2. Read the chosen particles: For each particle pair the tool shows which alternant attaches to your noun and why, based on the final-sound rule. 3. Learn the roles: Browse the full table to see each particle's grammatical function with both alternants listed side by side. FAQ: Q: What is a 받침 and why does it matter? A: A 받침 (batchim) is a final consonant at the bottom of a Korean syllable block. Many particles have two forms, and the choice between them depends entirely on whether the preceding noun ends in a batchim (consonant) or in a vowel. Picking the wrong alternant sounds clearly ungrammatical. Q: What is the difference between 은/는 and 이/가? A: 은/는 is the topic marker, framing what the sentence is about and often implying contrast, while 이/가 is the subject marker that identifies the doer, frequently with new information. The two-form split within each pair is purely phonological: 은 and 이 follow consonants, 는 and 가 follow vowels. Q: How do I choose between 을 and 를? A: 을 and 를 both mark the direct object. Use 을 after a noun ending in a consonant and 를 after a noun ending in a vowel. For example 밥을 (rice + object) but 사과를 (apple + object). The rule is the same consonant-versus-vowel test used by the other paired particles. Q: Does 으로/로 follow the same rule? A: Almost. 으로 attaches to consonant-final nouns and 로 to vowel-final nouns, but there is one exception: nouns ending in the consonant ㄹ (rieul) take 로, not 으로. So 손으로 (with the hand) but 칼로 (with a knife), because 칼 ends in ㄹ. Q: Are all Korean particles paired? A: No. Some particles such as 의 (possessive), 에 (location/time), 에서 (from/at), 도 (also), and 부터/까지 (from/until) have a single form regardless of the preceding sound. Only a handful of high-frequency particles have the consonant/vowel alternation, but those are the ones learners use constantly. #### Korean Romanization Converter URL: https://geratools.com/korean-romanization-converter Free Korean romanization tool — transliterate Hangul to Latin letters using the official Revised Romanization of Korean or the scholarly McCune-Reischauer scheme, right in your browser. Nothing is uploaded. How to use: 1. Pick a scheme: Choose Revised Romanization (the official South Korean system) or McCune-Reischauer (the scholarly standard). 2. Enter Hangul: Type or paste Korean syllable blocks such as 한국어 into the input box. 3. Read and copy: The Latin transliteration appears instantly; click Copy to grab the result. FAQ: Q: What is Revised Romanization? A: Revised Romanization of Korean (국어의 로마자 표기법) is the official system adopted by South Korea in 2000. It avoids diacritics and apostrophes, writing 부산 as Busan and 서울 as Seoul. Q: How does McCune-Reischauer differ? A: McCune-Reischauer (MR) is the older scholarly system still common in academia and North Korea. It uses breves and apostrophes, writing 부산 as Pusan and distinguishing aspirated consonants with apostrophes. Q: Does it apply sound-change rules? A: The tool romanizes each syllable's jamo with standard initial, medial, and final letter values. It does not model every cross-syllable assimilation rule, so proper nouns may need manual adjustment. Q: What happens to non-Hangul characters? A: Spaces, punctuation, numbers, and Latin letters pass through unchanged. Only composed Hangul syllable blocks in the U+AC00 to U+D7A3 range are transliterated. Q: Is my text uploaded? A: No. The conversion runs entirely in your browser using built-in jamo tables, so nothing is sent to any server. #### Malay Currency in Words URL: https://geratools.com/malay-currency-in-words Convert Malaysian ringgit amounts into full Bahasa Melayu word form, with the ringgit and sen parts spelled out and joined with dan, using the ribu and juta scale and a closing sahaja. Built for Malaysian banking and legal documents, all in your browser. How to use: 1. Enter the amount: Type the ringgit amount including any sen decimal, for example 1250.75. Commas and spaces are ignored. 2. Read the words: The ringgit and sen parts appear spelled out in Bahasa Melayu, joined with dan and closed with sahaja. 3. Copy the result: Press Copy to put the full Malay phrasing on your clipboard, ready for a cheque or contract. FAQ: Q: How does Malay group large numbers? A: Malay groups in thousands: ribu (thousand), juta (million), bilion (billion), and trilion (trillion). The tool spells each three-digit block then attaches the scale word, so 1,250 ringgit becomes seribu dua ratus lima puluh ringgit. Q: Why is 100 seratus and 1000 seribu? A: Malay uses the se- prefix (meaning one) for exactly one hundred and one thousand: seratus, not satu ratus, and seribu, not satu ribu. Larger multiples use the regular form, such as dua ratus for 200 and dua ribu for 2,000. The tool applies these rules automatically. Q: What does sahaja at the end mean? A: Sahaja means only or nothing more. It is the standard closing on Malaysian financial documents and cheques, marking the written amount as final so it cannot be altered. Q: How are sen subunits handled? A: The amount is multiplied by 100 and rounded to whole sen to avoid floating-point error, then split into ringgit and sen. So 1250.75 yields exactly 1250 ringgit and 75 sen, and the sen clause is added only when sen is greater than zero. Q: Does the tool keep my data private? A: Yes. All number spelling and rounding happen in your browser with Malay number tables. Nothing you type is uploaded, logged, or stored on any server. #### Persian RTL Direction Fixer URL: https://geratools.com/persian-rtl-direction-fixer Fix mangled bidirectional rendering of Persian text in left-to-right environments by wrapping it in Unicode direction controls (RLI/PDI, RLE/PDF, or RLM). Strips existing controls first so wrapping is idempotent. Runs entirely in your browser. How to use: 1. Paste the broken text: Drop the Persian text that renders in the wrong order into the input box. 2. Pick a wrapping method: Choose RLI isolate (recommended), RLE embedding (legacy), or an RLM prefix. 3. Copy the fixed text: Copy the wrapped output; it looks identical but carries hidden direction controls. FAQ: Q: Why does Persian text render in the wrong order? A: When right-to-left text sits in a left-to-right host such as a code comment or a CSV cell, the bidirectional algorithm can reorder punctuation, numbers, and embedded Latin incorrectly. Direction controls tell the host to display the run right-to-left. Q: Which wrapping method should I use? A: RLI…PDI (Right-to-Left Isolate) is the modern, recommended choice because it isolates the run without affecting surrounding text. RLE…PDF is an older embedding that most systems still support, and a plain RLM prefix is the lightest hint. Q: Will the fixed text look different? A: No. The added controls are invisible format characters, so the visible text is unchanged. Only the rendering direction is corrected. Q: Is wrapping safe to run twice? A: Yes. The tool strips any existing bidi control characters before re-wrapping, so applying it repeatedly will not stack duplicate controls. Q: Is my text uploaded? A: No. The wrapping happens entirely in your browser. Nothing you paste is sent to a server or stored. #### Pinyin Tone Number ↔ Accent Converter URL: https://geratools.com/pinyin-tones Free pinyin tone converter — turn numbered pinyin (ma1, zhong1) into accented Unicode forms (mā, zhōng) and back, using the correct tone-mark placement rule, in your browser. Nothing is uploaded. How to use: 1. Choose a direction: Pick numbers to accents, or accents back to numbers, depending on your input. 2. Enter pinyin: Type syllables with tone numbers like ni3 hao3, or accented pinyin like nǐ hǎo. 3. Read and copy: The converted pinyin updates instantly; click Copy to grab the result. FAQ: Q: What do the pinyin tone numbers mean? A: Mandarin has four tones plus a neutral tone. The numbers 1 to 4 mark the high, rising, dipping and falling tones, and 5 or 0 marks the neutral tone, which carries no accent. Q: Where does the tone mark go in a syllable? A: The mark follows a fixed rule: if there is an a or e it goes there; in the vowel pair ou it goes on the o; otherwise it goes on the last vowel of the syllable. Q: How is the ü handled? A: Type v or ue for ü. The tool places the tone mark over ü, giving forms such as lǜ for lü4, and the dots are kept on the neutral tone. Q: Can it convert accents back to numbers? A: Yes. The reverse direction strips each tone mark, appends the matching number 1 to 4 after the syllable, and leaves neutral-tone syllables without a number. Q: Is my text uploaded? A: No. The conversion runs entirely in your browser using a built-in vowel table, so nothing is sent to a server. #### Portuguese Number to Words URL: https://geratools.com/portuguese-number-words Spell out integers in Portuguese with correct gender agreement (um/uma, dois/duas, duzentos/duzentas), cem versus cento, the e connector rules, and European versus Brazilian forms (dezasseis vs dezesseis, mil milhões vs bilhão). Runs in your browser. How to use: 1. Enter a whole number: Type an integer into the box. The tool spells it out in Portuguese instantly, with no button to press. 2. Choose gender and variant: Pick masculine or feminine agreement for ones and hundreds, and switch on European Portuguese for the EU spellings and long-scale names. 3. Read the spelled-out number: The result shows the full por extenso form with the correct e connectors between groups. FAQ: Q: How does gender agreement work? A: The numbers one and two and all the hundreds from 200 to 900 agree in gender with the noun they count. Masculine gives um, dois, duzentos, trezentos, and feminine gives uma, duas, duzentas, trezentas. Only the units group of a large number takes the selected gender; thousands and millions are always read in the masculine, so two thousand chairs is duas mil only for the final part, while the scale words stay masculine. Q: When is it cem and when is it cento? A: Exactly one hundred is cem, as in cem livros. Any number from 101 to 199 uses cento, as in cento e um and cento e cinquenta. The tool applies this automatically based on whether the hundreds group is exactly 100. Q: What do the e connectors follow? A: Portuguese joins the parts inside a three-digit group with e (cento e vinte e três) and inserts e before the final group when that group is below 100 or is a round hundred (mil e duzentos, mil e cinquenta). When the final group is between 101 and 999 and not a round hundred, no e is used (mil duzentos e trinta). Q: What changes between European and Brazilian Portuguese? A: The teens 16, 17, and 19 are dezasseis, dezassete, and dezanove in European Portuguese versus dezesseis, dezessete, and dezenove in Brazilian. The large scales also differ: Brazilian uses the short scale (bilhão for 10^9, trilhão for 10^12), while European Portuguese uses mil milhões for 10^9 and bilião for 10^12. Q: Why does one thousand show as mil and not um mil? A: Portuguese drops the leading um before mil, so 1000 is mil, not um mil. The same applies to the European long-scale mil milhões, which is written without a leading um. The tool handles both cases. #### Russian Date in Words URL: https://geratools.com/russian-date-words Convert any date to Russian words with the day as an ordinal, the month in the genitive case, and the year as an ordinal genitive. Pick a date and copy the full spoken form, generated entirely in your browser. How to use: 1. Pick a date: Choose any date between the years 1000 and 2999 using the date picker. 2. Read the words: The tool writes the day as a neuter ordinal, the month in the genitive case, and the year as an ordinal genitive ending in года. 3. Copy the result: Press Copy to put the full Russian phrase on your clipboard for documents, letters, or contracts. FAQ: Q: Why is the day written like четвёртое and not четыре? A: The day of the month is an ordinal number agreeing with the neuter noun число, so it takes the neuter nominative ordinal form: первое, второе, четвёртое, двадцать пятое, and so on, never the plain cardinal. Q: Why is the month in the genitive case? A: Russian expresses 'of June' with the genitive: июня, not июнь. The construction is literally 'the fourth of June', so every month appears in its genitive form (января, февраля, июня, декабря). Q: Why does the year end in шестого года? A: The year is an ordinal in the genitive case because it answers 'of which year'. Only the final element becomes the ordinal genitive, so 2026 reads две тысячи двадцать шестого года, with the leading parts as cardinals. Q: What date range is supported? A: The tool handles years from 1000 to 2999, covering one-thousand and two-thousand year prefixes (тысяча and две тысячи). This spans all realistic historical and contemporary dates. Q: Can I use the output in formal documents? A: Yes. This long-hand form is the standard way dates are written out in Russian contracts, certificates and official letters, where spelling the date in words reduces ambiguity and tampering. #### Russian Romanization (Transliteration) URL: https://geratools.com/russian-transliteration Transliterates Russian Cyrillic into Latin script under four official schemes — GOST 7.79 System B, ISO 9, BGN/PCGN, and the Russian passport rules — each handling ъ, ь and й differently. Runs entirely in your browser. How to use: 1. Paste Russian text: Enter the Cyrillic words or names you want to romanize. Conversion runs in your browser. 2. Pick a scheme: Choose GOST 7.79 B, ISO 9, BGN/PCGN, or the Russian passport rules depending on the standard you need. 3. Copy the Latin output: Read the transliterated text and copy it into your document, form, or database. FAQ: Q: Which scheme should I use? A: For official Russian travel documents use the Passport scheme. ISO 9 gives a strict reversible one-letter-per-letter mapping for libraries and databases. BGN/PCGN is the readable English-oriented standard used on maps. GOST 7.79 System B is an ASCII-only reversible system for technical use. Q: How do the schemes treat ъ and ь? A: They differ a lot: ISO 9 maps ъ to a double prime and ь to a prime, GOST System B uses double and single apostrophes, BGN/PCGN renders ъ as a double quote and ь as a single quote, and the passport rules drop both signs entirely. Q: Why does й come out differently in each? A: й is a classic divergence point. ISO 9 uses j, GOST System B uses j, BGN/PCGN uses y, and the passport scheme uses i. Choosing the wrong scheme for a name on an official form is a common cause of mismatches. Q: Is the transliteration reversible? A: ISO 9 and GOST 7.79 System B are designed to be reversible, so the original Cyrillic can be reconstructed unambiguously. BGN/PCGN and the passport scheme favour readability and are not strictly reversible, since several Cyrillic letters can map to the same Latin output. Q: Is my text uploaded anywhere? A: No. All four mapping tables are bundled into the page and conversion happens in your browser. The names or text you enter never leave your device, so personal data stays private. #### Tamil Script Reference URL: https://geratools.com/tamil-script-reference Free Tamil script reference showing the full 247-letter set: 12 uyir vowels, 18 mei consonants, 216 uyirmei combinations, and the aytam, with romanization, search, and click-to-copy. Runs in your browser. How to use: 1. Browse the grid: The table shows each consonant as a row and each vowel as a column, forming the 18 × 12 uyirmei matrix. 2. Filter by syllable: Type a romanized syllable such as ka or no to highlight and narrow the grid to matching letters. 3. Click to copy: Click any glyph to copy that exact Tamil character to your clipboard. FAQ: Q: Why are there 247 Tamil letters? A: The Tamil set has 12 uyir vowels, 18 mei consonants, 216 uyirmei formed by combining each of the 18 consonants with each of the 12 vowels, and 1 aytam. That totals 247: 12 plus 18 plus 216 plus 1. Q: What is a uyirmei? A: A uyirmei is a living-body letter, a consonant joined with a vowel. The first column uses the bare consonant, which already carries the inherent vowel a, and the other columns add a dependent vowel sign to form syllables like கா and கி. Q: How is the mei column formed? A: The first labelled column shows the pure consonant, or mei, written with the pulli mark ். The pulli silences the inherent vowel, so க becomes க், the bare k sound. Q: Can I copy individual characters? A: Yes. Click any glyph in the table and it is copied to your clipboard, which is handy when a character is hard to type on your keyboard layout. Q: Does the chart load any data online? A: No. The grid is generated in your browser by combining the consonant and vowel tables, so nothing is fetched from a server. #### Telugu Number to Words URL: https://geratools.com/telugu-number-to-words Convert any whole number into Telugu words using standard cardinal names and the Indian lakh and crore scale. Handles units, tens, hundreds, thousands, lakhs, and crores correctly. Runs in your browser. How to use: 1. Type a number: Enter any whole number, with or without commas. Decimals are not supported because Telugu cardinals describe integers. 2. Read the Telugu words: The tool spells the number using standard Telugu cardinal names and the lakh and crore scale. 3. Copy if needed: Use the copy button to place the Telugu words on your clipboard for cheques, invoices, or documents. FAQ: Q: What number scale does this use? A: It uses the Indian numbering system, which Telugu speakers use. After thousand comes లక్ష (lakh, 100,000) and then కోటి (crore, 10,000,000), rather than the Western million and billion. So 1,00,000 reads as ఒక లక్ష. Q: How are tens and units written? A: Numbers 0 to 19 have their own words, and the tens (20, 30, …, 90) have dedicated stems such as ఇరవై and ముప్పై. A value like 21 is rendered as the tens word followed by the unit word, for example ఇరవై ఒకటి. Q: Does it handle hundreds, thousands, and crores? A: Yes. One hundred is వంద and higher hundreds use the multiplier with వందల. Thousand is వెయ్యి, with multiples using వేల. Lakhs use లక్షల and crores use కోట్ల, so a number like 1,23,456 is fully spelled out. Q: Can I enter very large numbers? A: Yes, up to the safe integer limit, which is about nine quadrillion. Beyond that, JavaScript cannot represent the value exactly, so the tool asks for a smaller number instead of risking a wrong result. Q: Is the conversion done privately? A: Yes. The number is converted in your browser with JavaScript and nothing is sent to a server. That makes the tool safe for financial figures and confidential amounts. #### Thai IPA Transcription Tool URL: https://geratools.com/thai-ipa-transcriber Convert Thai script to IPA in your browser, mapping consonants and vowels to phonemic symbols and computing the lexical tone from the consonant class, tone mark, vowel length, and syllable type. How to use: 1. Paste Thai text: Enter Thai script. The tool maps each consonant and vowel to IPA and reads any tone marks present. 2. Read the IPA with tone marks: Each syllable is given with an IPA tone diacritic from the five-way contour set derived by the Thai tone rules. 3. Check the tone class: A notes panel reports the consonant class (high/mid/low) used to compute the tone, since the same mark yields different tones by class. FAQ: Q: How does Thai compute tone? A: Thai tone depends on four factors: the initial consonant class (high, mid, or low), the presence and type of tone mark, the vowel length, and whether the syllable is live or dead. The tool applies the standard tone-rule table to derive one of five tones. Q: What are the five Thai tones? A: Mid (˧), low (˨˩), falling (˥˩), high (˦˥), and rising (˩˩˦). The tool marks each with the matching IPA chao tone letters so the contour is explicit, not just a name. Q: What is a live versus dead syllable? A: A live syllable ends in a long vowel or a sonorant (m n ŋ j w); a dead syllable ends in a stop (p t k) or a short vowel. Dead syllables follow different tone rules, which the tool detects from the final. Q: Does it handle silent letters? A: It does not resolve the karan (thanthakhat) silencing mark or complex cluster reordering. It is a syllable-level transcriber: give it clean syllables for the most accurate tone and segment output. #### Thai Script Reference URL: https://geratools.com/thai-script-reference A searchable reference showing all 44 Thai consonants grouped by their tone class (high, mid, low), the main vowel forms, and the four Thai tone marks with names and Latin values. How to use: 1. Browse the tables: Scroll the consonant, vowel, and tone-mark tables to see every Thai character with its name and romanized value. 2. Filter consonants by class: Use the class buttons to show only high, mid, or low consonants, which determine the tone of a syllable. 3. Search by sound or name: Type a Latin sound or character name to filter the consonant list and find the Thai letter you need. FAQ: Q: How many consonants does Thai have? A: Thai has 44 consonant letters, though two (ฃ and ฅ) are now obsolete and no longer used in modern writing. They represent 21 distinct consonant sounds, which is why several letters share the same Latin value. Q: What are the three consonant classes for? A: Every Thai consonant belongs to a high, mid, or low class. The class of the initial consonant, combined with the syllable type and any tone mark, determines which of the five Thai tones the syllable carries. Knowing the class is essential to reading tones correctly. Q: How many tones and tone marks does Thai have? A: Thai has five tones (mid, low, falling, high, rising) but only four written tone marks: ไม้เอก, ไม้โท, ไม้ตรี, and ไม้จัตวา. The mark plus the consonant class plus the syllable type together select the actual tone. Q: Why do some consonants look almost identical? A: Several Thai letters differ only by small loops or position, such as ค and ด, or ก and ถ. Each is a separate character with its own name and class, so reading carefully matters. The reference lists each letter's acrophonic name to tell them apart. Q: Are Thai vowels written as separate letters? A: No. Thai vowels are diacritic-like signs placed before, after, above, or below the consonant they modify, and some wrap around it. The vowel table here shows each form with a placeholder dash marking where the consonant sits. #### Turkish Date in Words URL: https://geratools.com/turkish-date-words Convert a calendar date to written Turkish: the cardinal day number, the capitalised Turkish month name, and the cardinal year, with an optional possessive suffix on the month for formal phrasing. Runs in your browser. How to use: 1. Choose a date: Pick a date in the date field or type the day, month, and year you want written out in Turkish. 2. Read the Turkish phrase: The tool builds the cardinal day, the capitalised month name, and the cardinal year, optionally adding the possessive suffix to the month. 3. Copy the wording: Use the copy button to put the Turkish date phrase on your clipboard for documents, letters, or learning. FAQ: Q: Are Turkish dates cardinal or ordinal? A: Standard Turkish dates use cardinal numbers for both the day and the year. The fourth of June is dört Haziran, literally four June, and the year follows as a plain cardinal: iki bin yirmi altı for 2026. Q: Why are Turkish month names capitalised? A: In Turkish, month names are proper nouns and are always written with an initial capital: Ocak, Şubat, Mart, and so on. This differs from Dutch or French, where month names are lowercase. Q: What is the possessive suffix on the month? A: In formal phrasing such as 'the fourth of June' Turkish can mark the month with the genitive or possessive suffix, giving Haziran'ın dördü. The tool offers this form with the apostrophe required before suffixes on proper nouns. Q: How is the year spelled in Turkish? A: Turkish builds large numbers left to right with no joining word: 2026 is iki bin yirmi altı (two thousand twenty six). The word bin is used for thousand, and milyon for million, written as separate words. Q: Does it use Turkish-specific letters? A: Yes. The output uses the Turkish alphabet including ı, ş, ç, ğ, and ü, so number words like altı, yedi, and dokuz and month names like Ağustos appear with correct Turkish spelling. #### Urdu Nastaliq Script Reference URL: https://geratools.com/urdu-nastaliq-reference Shows the Urdu-only characters (ٹ ڈ ڑ ں ہ ی ے) with their Unicode points, names, and transliterations. Browse the letters that distinguish Urdu from Arabic and Persian script. How to use: 1. Scan the table: Each row shows an Urdu-only letter, its name, transliteration, and Unicode code point. 2. Read the explanation: The notes column tells you why the letter exists and which sound it captures that Arabic and Persian do not. 3. Copy a letter: Click any glyph or its code point to copy it to your clipboard for use in documents or code. FAQ: Q: How is the Urdu alphabet different from Arabic? A: Urdu uses the Perso-Arabic script but adds letters for sounds found in South Asian languages. The most distinctive are the retroflex consonants ٹ ڈ ڑ, the nasal ں (nun ghunna), the two forms of he (ہ and ھ), and the special ے (bari ye). Q: What are retroflex letters in Urdu? A: Retroflex consonants — ٹ (ṭe), ڈ (ḍal), and ڑ (ṛe) — are made with the tongue curled back against the roof of the mouth. They are written like their Arabic dental counterparts but with a small superscript ط (toe) to mark them. Q: What is the difference between ہ and ھ? A: ہ (gol he, 'round he') represents the /h/ sound and can carry vowels, while ھ (do-chashmi he, 'two-eyed he') is used only to write aspirated consonants such as بھ (bh) and کھ (kh). They are distinct Unicode characters. Q: What is bari ye (ے)? A: ے is the 'big ye' used at the end of a word for the long /e/ or /ai/ vowel, distinct from the regular ی (choti ye) used initially and medially. It is one of the most recognisable Urdu-specific letters. Q: Does this tool send my data anywhere? A: No. The table is static and the copy feature runs in your browser. Nothing is uploaded to any server. #### Urdu Number to Words URL: https://geratools.com/urdu-number-to-words Free converter that spells any whole number into Urdu words using Urdu's irregular 1–99 names and the Indian lakh/crore scale. Runs entirely in your browser — nothing is uploaded. How to use: 1. Type your number: Enter any whole number using ordinary Western digits. 2. Read the Urdu words: The spelled-out Urdu form appears instantly below, right-to-left. 3. Copy the result: Use the Copy button to paste the words into documents or cheques. FAQ: Q: Why can't Urdu numbers be built from a tens and a units word? A: Urdu has a distinct, irregular name for every number from 1 to 99, so 21 is اکیس and 19 is انیس rather than a predictable compound. This tool stores all 100 names in a lookup table to stay accurate. Q: Which numbering system does it use above 99? A: It uses the South Asian Indian system: سو (hundred), ہزار (thousand), لاکھ (100,000) and کروڑ (10,000,000). This differs from the Western thousand/million grouping. Q: Can it handle very large numbers? A: Yes — it supports up to ارب (1 billion) and کھرب (100 billion) scale words, covering numbers safely up to 15 digits. Q: Does it work with negative numbers? A: Yes. A negative value is prefixed with منفی (minus) before the spelled-out words. Q: Is my number sent to a server? A: No. The conversion runs completely in your browser with no network requests, so your data never leaves your device. #### Number to Words — Indian System (Lakh / Crore) URL: https://geratools.com/number-to-words-indian-system Free number-to-words converter for the Indian numbering system. Spell any number up to 13 digits in English using lakh, crore, arab and kharab grouping — ideal for cheques and invoices in India, Pakistan, Bangladesh, Nepal and Sri Lanka. Runs entirely in your browser; nothing is sent anywhere. How to use: 1. Type the number: Enter any whole or decimal number up to 13 digits (the kharab range). Commas are ignored, so 1,23,456 works too. 2. Read the words: The tool spells the number in English using the Indian system — thousand, lakh, crore, arab and kharab groupings. 3. Check the reference: Open the Indian numbering reference to see how each scale word maps to a digit count. FAQ: Q: How does the Indian system group digits? A: After the first thousand, the Indian system groups in pairs of two digits — 1,00,000 is one lakh, 1,00,00,000 is one crore, then arab and kharab. This differs from the Western thousand/million/billion grouping. Q: Is the result accurate enough for a cheque? A: The spelling follows the standard lakh/crore phrasing used on Indian cheques and invoices, but you should always re-read the output against the figure before signing any financial or legal document. Q: What is a lakh and a crore in numbers? A: A lakh is 100,000 (written 1,00,000 in the Indian style) and a crore is 10,000,000 (written 1,00,00,000). The next scale words are arab (1 billion) and kharab (100 billion). Q: How are decimals read? A: The whole part is spelled in lakh/crore form, then the fractional part is read digit-by-digit after the word "point" — so 12.34 reads "twelve point three four". This matches cheque and invoice conventions. Q: Does the number get sent to a server? A: No. All conversion runs locally in your browser with JavaScript. Nothing you type is transmitted, logged or stored anywhere. #### Number to Words in Portuguese (Números por Extenso) URL: https://geratools.com/number-to-words-portuguese Free number-to-words converter for Portuguese (números por extenso). Spell any number up to 12 digits in correct Portuguese — handling cem vs cento, the e connector, irregular hundreds and milhão/bilhão plurals. Runs entirely in your browser; nothing is sent anywhere. How to use: 1. Digite o número: Type any whole or decimal number up to 12 digits. Spaces and thousands separators are ignored. 2. Leia o resultado: The tool spells the number in Portuguese, applying cem vs cento, the e connector and milhão/milhões plurals. 3. Confira os exemplos: Open the examples to verify forms like 100, 123, mil e duzentos and one million. FAQ: Q: How does it handle cem, cento and the e connector? A: It uses standard Portuguese rules — 100 alone is cem, 101–199 begin with cento e, and e joins hundreds, tens and the final group (cento e vinte e três, mil e duzentos). It uses Brazilian short scale (milhão, bilhão). Q: Is the result safe to use on documents? A: The spelling follows standard Portuguese por-extenso conventions, but always proofread the words against the figure before using them on a cheque, contract or official form. Q: What is the difference between cem and cento? A: cem is used for exactly 100 on its own, while cento is used inside 101-199 — so 100 is cem but 123 is cento e vinte e três. Q: Does it use Brazilian or European Portuguese scale words? A: It uses the Brazilian short scale, where milhão is a million and bilhão a thousand million. The hundreds, tens and connector rules are shared with European Portuguese. Q: How are the irregular hundreds spelled? A: Several hundreds are irregular: 500 is quinhentos, 700 is setecentos and 900 is novecentos, rather than following the cinco/sete/nove pattern. The converter applies these forms automatically. Q: Are my numbers transmitted anywhere? A: No. The conversion runs entirely in your browser with JavaScript. Nothing you type is sent, logged or stored on any server. #### Number to Words in Arabic URL: https://geratools.com/number-to-words-arabic Free converter that spells any number into Arabic words (Modern Standard Arabic). Handles thousands, millions and billions with correct ألف/مليون/مليار forms. Runs 100% in your browser — nothing is uploaded. How to use: 1. Type your number: Enter any whole number up to 12 digits using normal digits. 2. Read the Arabic words: The spelled-out Arabic form appears instantly below, right-to-left. 3. Copy what you need: Select the result text to copy it into invoices, cheques or documents. FAQ: Q: Which Arabic dialect does this use? A: It uses Modern Standard Arabic (الفصحى) cardinal numbers in the common masculine form, which is what is used in writing and formal documents across the Arab world. Q: Does it handle the special forms like مئتان and ألفان? A: Yes — it uses the dual forms مئتان (200) and ألفان (2000), the plural آلاف/ملايين/مليارات for 3-10, and the connector و between groups. Q: How large a number can I convert? A: Up to 12 digits, which covers values into the billions (مليار). Larger groups are spelled with their plural scale words. Q: How are the scale words made plural? A: Arabic uses different forms by count: ألف for one thousand, ألفان for two thousand, and the plural آلاف for 3-10 thousands. The same pattern applies to مليون/ملايين and مليار/مليارات. Q: Does it read out decimals? A: This tool spells whole numbers. For monetary amounts, convert the whole part and add the fractional currency unit (such as قرش or فلس) yourself. Q: Is my number sent anywhere? A: No — the conversion runs entirely in your browser with no network requests. #### Number to Words in Georgian URL: https://geratools.com/number-to-words-georgian Free converter that spells any number into Georgian words, correctly handling the vigesimal (base-20) system for 20-99. Runs 100% in your browser — nothing is uploaded. How to use: 1. Type your number: Enter any whole number up to 12 digits using normal digits. 2. Read the Georgian words: The spelled-out form appears instantly below, using the base-20 system. 3. Copy what you need: Select the result text to copy it into documents or cheques. FAQ: Q: Why do Georgian numbers look like multiplication? A: Georgian uses a vigesimal (base-20) system. For example 40 is ორმოცი (literally two-twenties) and 80 is ოთხმოცი (four-twenties); 30, 50, 70 and 90 are "previous-twenty plus ten". Q: How are units joined to the tens? A: Units attach with the connector და (and) and the trailing word drops its nominative ending — so 21 is ოცდაერთი and 75 is სამოცდათხუთმეტი. Q: What does vigesimal mean? A: Vigesimal means base-20. Georgian counts the 20-99 range in twenties rather than tens, so the tens words are built from multiples of twenty plus an optional ten. Q: How large a number can I convert? A: Up to 12 digits, which covers values into the billions (მილიარდი). The thousand, million and billion scale words are added automatically. Q: Is my number sent anywhere? A: No — the conversion runs entirely in your browser with no network requests. #### Number to Words in Bengali URL: https://geratools.com/number-to-words-bengali Free converter that spells any number into Bengali (Bangla) words using the Indian system — হাজার, লক্ষ and কোটি. Runs 100% in your browser — nothing is uploaded. How to use: 1. Type your number: Enter any whole number up to 15 digits using normal digits. 2. Read the Bengali words: The spelled-out Bangla form appears instantly below. 3. Copy what you need: Select the result text to copy it into cheques, invoices or documents. FAQ: Q: Does this use lakh and crore? A: Yes — it uses the Indian numbering system, grouping after the hundreds into হাজার (thousand), লক্ষ (lakh, 100,000) and কোটি (crore, 10,000,000). Q: Why is there a full 0-99 table? A: Bengali numbers from 0 to 99 are largely irregular and do not split neatly into tens and units, so each is stored individually for accuracy — for example একুশ (21) and নিরানব্বই (99). Q: How does the Indian grouping differ from Western grouping? A: After the first thousand the Indian system groups in pairs of two digits: 1,00,000 is one lakh and 1,00,00,000 is one crore. The Western system instead groups in threes as thousand, million and billion. Q: How large a number can I convert? A: Up to 15 digits, covering values through লক্ষ (lakh) and কোটি (crore) and beyond. Q: Does it spell paisa or decimal amounts? A: It converts whole numbers. For currency, spell the taka amount here and add the paisa subunit separately. Q: Is my number sent anywhere? A: No — the conversion runs entirely in your browser with no network requests. #### Number to Words in Italian URL: https://geratools.com/number-to-words-italian Convert numbers to Italian words with correct vowel elision and accents (ventuno, ventitré, trentotto). Free, private, and 100% client-side — nothing is uploaded. How to use: 1. Type a number: Enter any whole number up to 12 digits in the input box. 2. Read the Italian spelling: The number is spelled out in Italian instantly as you type. 3. Note the elisions: Tens drop their final vowel before uno and otto — 21 is ventuno and 38 is trentotto. FAQ: Q: Why is 23 written ventitré with an accent? A: In Italian, tre takes an accent (tré) when it ends a compound number, so 23 is ventitré and 43 is quarantatré. Q: Why do some tens lose a letter? A: A tens word drops its final vowel before uno (1) and otto (8): venti + uno = ventuno, trenta + otto = trentotto. Q: Are Italian numbers written as one word? A: Yes. Italian numbers below a million are written as a single concatenated word — for example trecentoquarantacinque for 345. Q: How large a number can I convert? A: Up to 12 digits, covering values into the billions (miliardi). The scale words milione and miliardo are pluralised to milioni and miliardi when needed. Q: Is anything sent to a server? A: No. The conversion runs entirely in your browser — no number you type ever leaves your device. #### Number to Words in Chinese URL: https://geratools.com/number-to-words-chinese Convert numbers to Simplified Chinese numerals with correct 万/亿 grouping and zero rules (一千二百三十四, 一万, 十万零五). Free, private, and 100% client-side — nothing is uploaded. How to use: 1. Type a number: Enter any whole number up to 12 digits in the input box. 2. Read the Chinese numerals: The number is written out in Simplified Chinese instantly as you type. 3. Note the grouping: Chinese groups digits by four with 万 (10,000) and 亿 (100 million), not by three. FAQ: Q: Why does Chinese group by four digits? A: Chinese uses 万 for 10,000 and 亿 for 100 million as its scale units, so numbers are grouped in blocks of four — 10,000 is 一万 and 100,000 is 十万. Q: How are internal zeros handled? A: A run of internal zeros collapses to a single 零, and a trailing zero is dropped — so 100,005 is 十万零五, not 十万零零零五. Q: Are these Simplified or Traditional characters? A: The output uses everyday Simplified Chinese numerals (一 二 三 …, 十 百 千 万 亿). These are the common forms, not the anti-fraud financial characters (壹 贰 叁) used on formal cheques. Q: How large a number can I convert? A: Up to 12 digits, which spans the 万 (10,000) and 亿 (100 million) scale units used in Chinese. Q: Is anything sent to a server? A: No. The conversion runs entirely in your browser — no number you type ever leaves your device. ### More Text Tools #### Abbreviation & Acronym Expander URL: https://geratools.com/abbreviation-expander Scans pasted text for capitalised acronyms that are never defined in parentheses on first use, flagging each as a potential WCAG 3.1.4 (Abbreviations) issue. Includes a bundled list of common expansions (NHS, GDPR, URL, API) for auto-suggestion. Built for technical writers and accessibility editors. How to use: 1. Paste your copy: Drop in the document you want to check. The tool scans for capitalised acronyms entirely in your browser. 2. Review the flagged acronyms: Each acronym that is never expanded on first use is listed, with a suggested expansion pulled from a built-in dictionary where one exists. 3. Define on first use: Add the full term in parentheses the first time each flagged acronym appears, then re-paste to confirm the warnings clear. FAQ: Q: What does WCAG 3.1.4 (Abbreviations) require? A: It requires a mechanism to find the expanded form or meaning of abbreviations. The simplest way to satisfy it in body text is to spell out the full term on first use with the acronym in parentheses, for example 'Application Programming Interface (API)'. Q: How does the tool detect an acronym? A: It finds tokens of two or more capital letters (optionally with digits, like H2O or PDF417) and checks whether an expansion appears in parentheses nearby on first use. If none is found, the acronym is flagged. Q: Why are common acronyms still flagged? A: Even widely known acronyms can be unfamiliar to some readers or assistive tech, so WCAG asks for a definition mechanism. The tool suggests a known expansion where it has one, but you decide which acronyms your audience truly needs defined. Q: Does it count an acronym as defined if I expand it later? A: No. WCAG 3.1.4 is about the first occurrence, so the expansion must accompany or precede the first use. An acronym expanded only halfway through the document is still flagged on its first appearance. Q: Is my text sent to a server? A: No. The acronym dictionary is bundled into the page and all scanning runs in your browser. Your text never leaves your device, so internal documentation is safe to check. #### ASCII Art Text (FIGlet-style) URL: https://geratools.com/ascii-art-figlet Turn words into FIGlet-style ASCII art block letters right in your browser. Uses a built-in multi-row font to render A–Z and 0–9 as copy-paste text art for terminals, READMEs, and chat. Free and keyless. How to use: 1. Type your text: Enter the word or short phrase you want rendered as ASCII art. Lowercase letters are automatically uppercased. 2. Read the rendered art: The tool stacks each letter's rows side by side to form multi-line block text in a monospace preview. 3. Copy and paste: Click Copy and paste the art into a terminal, README, code comment, or chat message that uses a monospace font. FAQ: Q: What characters are supported? A: The built-in font covers A–Z and 0–9 plus spaces. Lowercase input is uppercased automatically, and any punctuation or symbol not in the font is simply skipped. Q: Is this real FIGlet? A: It is FIGlet-style — the same idea of mapping each character to a fixed set of text rows that are concatenated horizontally. It uses a compact built-in font rather than loading external .flf font files. Q: Why does the art look broken when I paste it? A: ASCII art only lines up in a monospace (fixed-width) font. In a proportional font the columns drift. Paste it into a code block, terminal, or any monospaced context. Q: Does it work offline? A: Yes. The font is embedded in the page and rendering is pure JavaScript, so once the page has loaded nothing is fetched and your text never leaves the browser. Q: Can I make a multi-line banner? A: This tool renders a single line of block letters. For very tall single-line banners, try the ASCII Banner Generator, which uses a 7-row font. #### ASS / SSA to SRT Converter URL: https://geratools.com/ass-to-srt Free ASS/SSA to SRT converter. Parses Dialogue lines, removes override tags like {\an8} and {\i1}, converts centisecond timestamps to SRT milliseconds, sorts and renumbers cues. 100% client-side. How to use: 1. Load or paste your ASS / SSA file: Drop in an .ass or .ssa file, or paste the script text. The tool reads the [Events] section and its Dialogue lines. 2. Review the converted SRT: Override tags are stripped, timestamps are converted, and cues are sorted into chronological order and renumbered from 1. 3. Copy or download the result: Copy the SRT text or download a ready-to-use .srt file that any media player accepts. FAQ: Q: What is the difference between ASS, SSA and SRT? A: SSA (SubStation Alpha) and its successor ASS (Advanced SubStation Alpha) are styled subtitle formats that support fonts, positioning and animated override tags. SRT (SubRip) is a plain format with just numbered cues, timecodes and text. This tool flattens the styled formats down to plain SRT. Q: What happens to override tags like {\an8} or {\i1}? A: All curly-brace override blocks are removed because SRT cannot represent them. Tags such as {\an8} (position), {\i1} (italic on) and colour or movement tags are stripped, leaving only the visible dialogue text. Q: Why do the timestamps change format? A: ASS uses H:MM:SS.cc with centiseconds (hundredths of a second), while SRT uses HH:MM:SS,mmm with milliseconds and a comma decimal separator. The converter multiplies centiseconds by ten and reformats each timecode accordingly. Q: Are line breaks preserved? A: Yes. ASS line breaks written as \N (hard break) or \n (soft break) are converted into real newlines inside the SRT cue, so multi-line captions stay on separate lines. Q: Is my subtitle file uploaded anywhere? A: No. Parsing, tag stripping and conversion all run in JavaScript inside your browser. Nothing is sent to a server, so unreleased or confidential subtitle scripts stay private on your device. #### BibTeX to APA 7 Reference List URL: https://geratools.com/bibtex-to-apa Free in-browser BibTeX to APA 7 converter. Parses BibTeX entries and formats each as an APA 7th edition reference — author-date order, inverted author names, sentence-case titles, italic journal and DOI display. Handles articles, books and more. Nothing is uploaded. How to use: 1. Paste your BibTeX: Paste one or more BibTeX entries (@article, @book, @inproceedings, etc.) into the box. 2. Let it format each entry: The tool parses authors, year, title, journal, volume, issue, pages and DOI, then renders APA 7 references. 3. Copy the reference list: Review the alphabetised, hanging-indent reference list and copy it into your document. FAQ: Q: Which APA edition does this follow? A: It follows APA 7th edition (2020). Up to 20 authors are listed before an ellipsis-and-final-author cut, journal titles and volumes are italicised, titles use sentence case, and DOIs are shown as full https://doi.org/ links. Q: How are author names handled? A: Each author is inverted to Surname, Initials. Two authors are joined with an ampersand; three or more use commas with an ampersand before the last. The list is alphabetised by the first author's surname, as APA requires. Q: Which entry types are supported? A: Common BibTeX types are handled — @article (journal), @book, @inbook/@incollection (chapter in an edited book), @inproceedings/@conference, @phdthesis/@mastersthesis, and @misc/@online (web sources). Unknown types fall back to a generic format. Q: Does it fix capitalisation? A: APA uses sentence case for article and book titles. The tool lowercases the title except the first word and the word after a colon, while preserving text you protected with curly braces in the BibTeX (for proper nouns and acronyms). Q: Is my bibliography uploaded? A: No. Parsing and formatting happen entirely in your browser, so your unpublished reference list never leaves your device. #### BibTeX to RIS Converter URL: https://geratools.com/bibtex-to-ris Free BibTeX to RIS converter. Maps BibTeX entry types and fields to RIS tags (TY, AU, TI, JO, SP, EP, DO) and produces a downloadable .ris file for EndNote, Mendeley or Zotero. Runs in-browser; citations never leave your device. How to use: 1. Load or paste your BibTeX: Drop in a .bib file or paste BibTeX entries directly into the input box. 2. Review the generated RIS: Each entry's type and fields are mapped to RIS tags, with authors and page ranges split correctly. Check the output on the right. 3. Copy or download the .ris file: Copy the RIS text or download a .ris file ready to import into EndNote, Mendeley, Zotero or RefWorks. FAQ: Q: What is the difference between BibTeX and RIS? A: BibTeX is a LaTeX-oriented reference format using @type{key, field = {value}} blocks. RIS is a tagged format where each line starts with a two-letter code such as TY, AU or TI, used by EndNote, Mendeley, Zotero and RefWorks. This tool maps one to the other. Q: How are entry types translated? A: BibTeX types map to RIS TY codes: @article becomes JOUR, @book becomes BOOK, @inproceedings becomes CPAPER, @phdthesis and @mastersthesis become THES, @techreport becomes RPRT, and unknown or @misc types fall back to GEN. Q: How are authors and page ranges handled? A: BibTeX joins authors with ' and ', so each author is split out onto its own AU line in RIS. A page range like 891--921 is split into SP (start page) and EP (end page) tags, which is what reference managers expect. Q: Which fields are converted? A: Author, editor, title, journal, booktitle, year, volume, number, pages, publisher, address, doi, url, isbn, issn, abstract and keywords are all mapped to their RIS equivalents. Keywords are split into one KW tag each. Q: Is my citation data uploaded anywhere? A: No. Parsing and conversion happen entirely in your browser using JavaScript. Nothing is sent to a server, so your reference library stays private on your own device. #### Chappe Optical Telegraph Encoder URL: https://geratools.com/chappe-telegraph Free Chappe optical telegraph encoder — map letters to the numeric arm codes of the 1790s French semaphore network and see the regulator and indicator arm angles for each character. Runs in your browser. How to use: 1. Type your message: Enter the text to encode. Letters are read case-insensitively and mapped to Chappe alphabet positions. 2. Read the arm codes: Each letter shows its Chappe code number and the corresponding regulator and indicator arm positions. 3. Copy the codes: Copy the numeric Chappe codes to share, or use the arm angles to picture the relay tower's pose. FAQ: Q: How did the Chappe optical telegraph work? A: Claude Chappe's system used towers with a movable crossbar (the regulator) carrying two jointed arms (indicators). Operators set the arms into distinct shapes, each standing for a code, and relayed the shapes tower to tower across France. Q: How many signals could it make? A: The regulator could take a few orientations and each indicator arm seven positions, giving 196 combinations in total. Around 92 of these were used as a working alphabet keyed to a code book. Q: How are letters encoded here? A: Each letter is mapped to a position number in the Chappe alphabet, and that number is shown alongside a simplified set of arm angles. This is a teaching approximation of the historical code book. Q: Why was it replaced? A: The optical telegraph needed clear daylight, line of sight, and a chain of staffed towers. The electrical telegraph of the 1840s worked at night and over wires, so it quickly made the Chappe network obsolete. Q: Is my text uploaded anywhere? A: No. The encoding runs entirely in your browser and nothing is sent to any server. #### Coin Flipper URL: https://geratools.com/coin-flipper Flip a fair digital coin with a 50/50 heads or tails result, then track totals, percentages, and your current streak. A simple tool for quick decisions and probability demonstrations. How to use: 1. Flip the coin: Press Flip the coin to run one fair toss with an even chance of heads or tails. 2. Read the stats: Watch the running totals, heads and tails percentages, and your current streak update after every flip. 3. Reset when needed: Click Reset to clear the history and start a fresh sequence of flips at any time. FAQ: Q: Is the coin truly fair? A: Yes. Each flip compares Math.random against 0.5, giving heads and tails an identical 50 percent probability. Over many flips the percentages converge toward 50/50. Q: Why did I get five heads in a row? A: Streaks are completely normal with fair randomness. A fair coin has no memory, so each flip is independent and runs of the same result happen by chance more often than people expect. Q: What does the streak counter show? A: It shows how many times in a row the most recent result has appeared. The moment the opposite side comes up, the streak resets to one for that new side. Q: Does it remember flips after I reload? A: No. The history lives only in the current page session. Reloading or pressing Reset clears all counts and starts over. Q: Can I use this to teach probability? A: Yes. Flipping many times and watching the percentages approach 50 percent is a clear demonstration of the law of large numbers, while the streaks illustrate independence of events. #### Devanagari ↔ IAST Transliterator URL: https://geratools.com/devanagari-iast Free Devanagari to IAST transliterator — convert Sanskrit/Hindi Devanagari to the diacritic IAST Latin scheme and back, instantly in your browser. No upload. How to use: 1. Choose direction: Pick Devanagari to IAST to romanize, or IAST to Devanagari to reverse it. 2. Paste your text: Enter the Devanagari script or the IAST Latin (with diacritics) you want to convert. 3. Read and copy: The transliteration updates as you type. Click Copy to grab the output. FAQ: Q: What is IAST? A: IAST (International Alphabet of Sanskrit Transliteration) is the academic standard for romanizing Devanagari and other Indic scripts. It uses Latin letters plus diacritics — macrons for long vowels, dots below for retroflex consonants — to represent every Sanskrit sound unambiguously. Q: How does the inherent vowel work? A: In Devanagari every consonant carries an inherent short a. The tool adds that a after each consonant unless a different vowel sign or a virama (halant) follows. The virama removes the inherent vowel, giving a bare consonant cluster. Q: Why do some letters have dots or lines above them? A: Those are the IAST diacritics: a macron (ā ī ū) marks a long vowel, a dot below (ṭ ḍ ṇ ṣ) marks a retroflex, ṛ marks vocalic r, ñ and ṅ mark palatal and velar nasals, and ḥ ṃ mark visarga and anusvara. Q: Is the conversion reversible? A: Most well-formed Sanskrit and Hindi round-trips cleanly. The tool matches multi-character IAST sequences such as kh, ṣ and ai longest-first, and handles the inherent vowel and virama, so standard text converts both ways reliably. Q: Is my text uploaded? A: No. The conversion uses a local lookup table in your browser, so nothing is sent to a server. #### Random Diacritic Adder URL: https://geratools.com/diacritic-add Add decorative random accent marks to plain text for a stylised metal or glitch effect. Attaches combining diacritics to letters at an adjustable density, all in your browser. Reversible with a diacritic stripper. How to use: 1. Type your text: Enter the plain text you want to decorate with accent marks. 2. Set the intensity: Use the slider to choose how many letters get a random diacritic, from a light sprinkle to heavy stacking. 3. Copy the stylised text: The decorated text updates live. Copy it for usernames, headings, or social posts that support Unicode. FAQ: Q: How does it add the accents? A: For each eligible letter the tool rolls against your chosen density and, on a hit, appends one or more random combining marks from the Unicode U+0300 to U+036F block. Because they are combining characters, they stack directly onto the preceding base letter. Q: Is this the same as Zalgo text? A: It is a lighter, controllable version of the same idea. Full Zalgo stacks many marks above and below for a chaotic look, while this tool lets you dial the density so the result stays readable or goes wild as you prefer. Q: Can I undo the effect? A: Yes. Because the original letters are untouched and only combining marks are added, a diacritic stripper that normalises to NFD and removes combining marks will return the plain original text exactly. Q: Where will this display correctly? A: Anywhere that renders Unicode combining characters, including most modern browsers, social platforms, and chat apps. Some systems clamp or strip excessive marks, and a few legacy fields reject non-ASCII entirely. #### DOI to Citation Formatter URL: https://geratools.com/doi-to-citation Fetches publication metadata from the keyless Crossref REST API and renders a citation in APA, MLA, Chicago, IEEE, Harvard, or BibTeX. No API key needed; only lightweight metadata is fetched in your browser. How to use: 1. Paste a DOI: Paste a DOI such as 10.1038/nature12373, with or without the https://doi.org/ prefix. 2. Pick a style: Choose APA, MLA, Chicago, IEEE, Harvard, or BibTeX as the output format. 3. Fetch and copy: Click Fetch to retrieve metadata from Crossref and render the citation, then copy it. FAQ: Q: Does this need an API key? A: No. It queries the public Crossref REST API at api.crossref.org, which is keyless and free. Only the work's bibliographic metadata is fetched — no account or token is required. Q: Which styles are supported? A: APA 7th, MLA 9th, Chicago author-date, IEEE, Harvard, and BibTeX. The citation is built from the Crossref metadata (authors, title, container, volume, issue, pages, year, DOI) using the rules for each style. Q: What if the DOI is not found? A: If Crossref returns a 404 or no metadata, the tool shows a clear error. Double-check the DOI for typos — DOIs are case-insensitive but must be complete, starting with the 10. prefix. Q: Does my DOI get logged anywhere by this tool? A: The tool itself stores nothing; the lookup is a direct browser request to Crossref. Crossref's own API may rate-limit by IP, but no Gera server sees your query. Q: Why does the author list sometimes look incomplete? A: Crossref metadata occasionally omits given names or lists organisations as authors. The formatter renders whatever names Crossref provides and falls back gracefully when a name part is missing. #### Maritime Flag Signal Encoder URL: https://geratools.com/flag-signal-encode Free maritime signal-flag encoder that converts text to International Code of Signals flag names (Alfa, Bravo, Charlie) and shows each flag's standalone meaning, all in your browser. How to use: 1. Type your message: Enter the text you want to spell out using maritime signal flags. 2. Read the flag names: Each letter becomes its International Code of Signals flag name, with the flag's own meaning shown. 3. Copy the result: Click Copy to grab the list of flag names for your message. FAQ: Q: What is the International Code of Signals? A: The International Code of Signals (ICS) is a standardised system of maritime flags where each letter has a named flag and a defined meaning, so ships of any nation can communicate without sharing a language. Q: Why do single flags have meanings? A: Each alphabet flag carries a standalone message when flown alone — for example, flag A (Alfa) means a diver is down, keep clear. This tool shows that meaning alongside each flag name. Q: How are digits handled? A: ICS includes ten numeral pennants for 0–9. This encoder spells letters as flag names and labels digits as numeral pennants rather than substituting a letter flag. Q: Is it case sensitive? A: No. Signal flags have no case, so uppercase and lowercase letters map to the same flag. Spaces between words are preserved as separators. Q: Is my text uploaded anywhere? A: No. The conversion uses a built-in table and runs entirely in your browser; nothing is sent to a server. #### Fullwidth Text Converter URL: https://geratools.com/fullwidth-convert Free fullwidth text converter — turns standard ASCII letters, digits and punctuation into their Unicode fullwidth (CJK-width) equivalents for aesthetic vaporwave-style spaced-out text. Runs in your browser. How to use: 1. Enter your text: Type or paste the ASCII text you want to widen. 2. Read the fullwidth output: Letters, digits and punctuation are swapped for their wide CJK-width forms instantly. 3. Copy the result: Click Copy to grab the aesthetic spaced-out text for posts and titles. FAQ: Q: What are fullwidth characters? A: Fullwidth characters are Unicode forms in the range U+FF01 to U+FF5E that occupy a full CJK character cell, the same width as a Chinese, Japanese or Korean glyph. They make Latin text look wide and evenly spaced. Q: How does the conversion work? A: Each printable ASCII character from U+0021 to U+007E is shifted by 0xFEE0 to its fullwidth equivalent. The regular space U+0020 is mapped to the ideographic space U+3000 so spacing stays consistent. Q: Why is this called aesthetic or vaporwave text? A: The wide, evenly spaced look became popular in vaporwave art and retro Japanese computing aesthetics, so fullwidth text is often used decoratively in usernames, titles and social posts. Q: Will it display on every device? A: Fullwidth characters are part of standard Unicode and render on most modern systems, though exact spacing depends on the font. Some apps that restrict character sets may strip them. Q: Is my text uploaded? A: No. The conversion happens entirely in your browser with JavaScript, so nothing you type leaves your device. #### German Umlaut Converter URL: https://geratools.com/german-umlaut-converter Convert German umlauts to and from their ASCII digraph equivalents — ä↔ae, ö↔oe, ü↔ue and ß↔ss — for legacy systems, URLs, email addresses and alphabetical sorting, with case-aware uppercase handling. How to use: 1. Choose a direction: Pick whether to turn umlauts into ASCII digraphs or digraphs back into umlauts. 2. Paste your text: Enter the German words or whole paragraphs you want to convert. 3. Copy the result: The converted text appears instantly and can be copied with one click. FAQ: Q: How are German umlauts converted to ASCII? A: The accepted transliteration replaces ä with ae, ö with oe, ü with ue, and the sharp-s ß with ss. This is the official substitution used when umlauts cannot be displayed, for example in passport names and older computer systems. Q: Does case get handled correctly? A: Yes. The capital umlauts Ä, Ö and Ü become Ae, Oe and Ue in title case, but in an all-uppercase context they become AE, OE and UE. So Äpfel gives Aepfel while ÄPFEL gives AEPFEL. Q: Why is converting ASCII back to umlauts ambiguous? A: Many German words naturally contain ae, oe, ue or ss without any umlaut, such as Aerobic, Poet or Wasser. The tool converts every matching digraph, so you should review the output and correct any false conversions. Q: Is ß the same as ss? A: For ASCII transliteration ß is written as ss, and that is the standard fallback. They are not always interchangeable in real spelling though — ss after a short vowel and ß after a long vowel or diphthong are distinguished in modern orthography. Q: Does this tool send my text anywhere? A: No. All conversion happens locally in your browser, so the text you enter is never uploaded. #### Hindi Sandhi Junction Identifier URL: https://geratools.com/hindi-sandhi-identifier Flags word boundaries and internal positions where common Sanskrit and Hindi sandhi rules — vowel coalescence, visarga, and consonant junctions — may apply, to assist editors and learners. Runs entirely in your browser. How to use: 1. Paste Devanagari text: Enter the Hindi or Sanskrit-origin text you want to scan for sandhi junctions. 2. Review highlighted junctions: The tool marks positions where vowel, visarga, or consonant sandhi rules typically operate, with the rule name. 3. Edit with context: Sandhi is context-sensitive, so use the flags as candidates and confirm each against meaning before changing the text. FAQ: Q: What is sandhi? A: Sandhi is the set of euphonic-combination rules inherited from Sanskrit by which sounds at the junction of words or morphemes merge or change. For example अ plus आ combines to आ, and इ plus अ yields य. Hindi keeps many of these in tatsama (Sanskrit-derived) vocabulary. Q: What are the main categories of sandhi? A: The three classical categories are swar sandhi (vowel junctions), vyanjan sandhi (consonant junctions), and visarga sandhi (changes affecting the visarga ः). This tool flags candidate sites for each by examining the characters on either side of a junction. Q: Why are these only candidates? A: Whether sandhi actually applies depends on word origin and meaning, which a surface scan cannot fully determine. Tadbhava and foreign-origin words may share the same letter sequences without undergoing sandhi, so each flag should be confirmed by an editor. Q: Does it split or join words for me? A: No. The tool only highlights where sandhi rules commonly operate and names the relevant category. It does not perform sandhi-viccheda (splitting) or sandhi formation automatically, since both require lexical knowledge of the underlying words. #### Hindi Vowel Matra Reference URL: https://geratools.com/hindi-vowel-reference Shows all Hindi vowels in independent form and as matra (vowel sign) attached to the consonant क as a worked example, with transliteration and Unicode for each. How to use: 1. Read the independent column: The first column shows each vowel as it appears at the start of a syllable or word, standing on its own. 2. Compare the matra form: The next column shows the same vowel as a sign attached to a consonant, demonstrated on क (ka). 3. Copy what you need: Click any glyph or its code point to copy it for use in documents, language notes, or code. FAQ: Q: What is a matra in Hindi? A: A matra (मात्रा) is the dependent sign a vowel takes when it follows a consonant. The independent vowel आ becomes the matra ा, which attaches to a consonant — so क (ka) plus ा gives का (kā). Every vowel except the inherent 'a' has a matra. Q: Why does क have no visible matra for the 'a' sound? A: Every Devanagari consonant carries an inherent short 'a' vowel by default. So क already reads as 'ka' with no sign added. To remove that inherent vowel you add a halant (virama): क् is a bare 'k'. Q: How many vowels does Hindi have? A: Standard Hindi has 11 main vowels in modern usage (अ आ इ ई उ ऊ ए ऐ ओ औ plus ऋ in Sanskrit loanwords), giving the chart its core rows. Older charts also list अं (anusvara) and अः (visarga) as related signs. Q: Where does the i-matra (ि) appear? A: Although the short-i vowel sound comes after the consonant, its matra ि is written before the consonant on the page — कि for 'ki'. This is the one matra placed to the left, which often surprises learners. Q: Is anything uploaded? A: No. The chart is generated in your browser and the copy buttons work locally. Nothing you click is sent to a server. #### ICS RRULE Occurrence Expander URL: https://geratools.com/ics-rrule-expander Free RRULE expander for iCalendar recurrence rules. Paste an RRULE like FREQ=WEEKLY;BYDAY=MO,WE with a DTSTART and see every concrete occurrence date up to your chosen cutoff. Supports BYDAY ordinals, BYSETPOS, UNTIL and COUNT, all in your browser. How to use: 1. Enter the RRULE: Paste the recurrence rule, for example FREQ=MONTHLY;BYDAY=2TU. The leading RRULE: prefix is optional. 2. Set DTSTART and a cutoff: Provide the start date-time (DTSTART) and the date to expand up to. Use YYYYMMDDTHHMMSSZ or an ISO date like 2026-12-31. 3. Read the occurrences: The tool lists every concrete occurrence in order, with weekday names, and lets you copy the full ISO list. FAQ: Q: What is an RRULE? A: An RRULE is the recurrence rule used in iCalendar (.ics) files, defined by RFC 5545. It encodes how an event repeats, such as FREQ=WEEKLY;BYDAY=MO,WE,FR for every Monday, Wednesday and Friday. Calendar apps read it to generate the individual instances of a repeating event. Q: Which RRULE parts are supported? A: FREQ for DAILY, WEEKLY, MONTHLY and YEARLY, plus INTERVAL, COUNT, UNTIL, BYDAY including ordinals like 2MO or -1FR, BYMONTHDAY, BYMONTH, BYSETPOS and WKST. These cover the vast majority of real recurring events. Q: How do ordinal BYDAY values work? A: An ordinal prefixes a weekday to pick a specific one in the period. With FREQ=MONTHLY, BYDAY=2TU means the second Tuesday of each month and BYDAY=-1FR means the last Friday. Without an ordinal, BYDAY=TU matches every Tuesday in the period. Q: Why are times shown in UTC? A: Recurrence expansion is computed in UTC so results are deterministic regardless of your local timezone or daylight-saving changes. If your DTSTART ends with Z it is already UTC; if you supply a local wall time, treat the output as that same clock time in UTC. Q: Is anything uploaded? A: No. The rule is parsed and expanded entirely in your browser with JavaScript. Nothing is sent to a server, so private calendar rules stay on your device. #### ICS Timezone Shifter URL: https://geratools.com/ics-timezone-shifter Convert every DTSTART, DTEND, EXDATE and RDATE datetime in an .ics calendar file from a source IANA timezone to a target zone, with DST-aware offsets computed in your browser. Export the updated ICS — no upload needed. How to use: 1. Choose the source and target zones: Set the source IANA timezone the events are currently written in, and the target zone you want them shifted to. Both lists use standard IANA identifiers like Europe/London or America/New_York. 2. Load or paste your ICS: Upload an .ics file or paste its contents into the box. The tool reads it locally; nothing is sent to a server. 3. Download the shifted calendar: Review the count of shifted datetimes and the preview, then download the updated .ics or copy the output to your clipboard. FAQ: Q: Which properties does it shift? A: It re-stamps DTSTART, DTEND, EXDATE, RDATE and RECURRENCE-ID values that include a time component. All-day VALUE=DATE entries have no time and are intentionally left unchanged. Q: Are daylight-saving changes handled correctly? A: Yes. Each datetime is first resolved to its exact absolute instant using your browser's timezone database, accounting for whatever DST offset applied on that date, then re-expressed in the target zone. A summer event and a winter event can therefore shift by different amounts. Q: What happens to the TZID parameter? A: When you shift to a named zone, the TZID parameter on each property is rewritten to the target zone. When you shift to UTC, the TZID is removed and a trailing Z is added so the value is an absolute UTC time. Q: Does it convert times that already end in Z? A: Yes. A value ending in Z is treated as UTC regardless of the source-zone selection, then converted to the target zone, so mixed-format calendars are handled consistently. Q: Is my calendar uploaded anywhere? A: No. Parsing, offset calculation and rewriting all happen in your browser with the File API. Your calendar data never leaves your device. #### ICS / iCal Validator URL: https://geratools.com/ics-validator Free ICS validator — paste an iCalendar file and check it against RFC 5545. It verifies BEGIN/END nesting, required properties on VEVENT/VTODO/VTIMEZONE, and date-time formats, then lists every error and warning. Runs entirely in your browser. How to use: 1. Paste your ICS: Drop the contents of your .ics file into the input box. 2. Run the check: The validator parses the file and lists structural and property-level problems instantly. 3. Fix and re-check: Address each reported error, paste the corrected text, and confirm it reports no errors. FAQ: Q: What does the validator check? A: It verifies that BEGIN and END tags are balanced and correctly nested, that the file begins with VCALENDAR and declares VERSION and PRODID, and that each VEVENT, VTODO, and VTIMEZONE has the properties RFC 5545 requires, such as UID and DTSTAMP. Q: Does a passing file mean my event is correct? A: It means the file is structurally valid and has the mandatory properties. It cannot judge whether your dates or recurrence rules describe what you intended, only that they are well-formed. Q: What date formats are accepted? A: DATE values like 20260610, UTC date-times ending in Z like 20260610T090000Z, and local or TZID date-times. The validator flags strings that do not match any of these patterns. Q: Why does it warn about line endings or folding? A: RFC 5545 requires CRLF line breaks and folds long lines at 75 octets with a leading space. Files using bare newlines still parse in most apps, so these are reported as warnings rather than hard errors. Q: Is my calendar uploaded? A: No. The whole file is parsed in your browser, so the events, attendees, and notes inside it stay completely private. #### IPA ↔ SAMPA Converter URL: https://geratools.com/ipa-sampa-convert Free IPA to SAMPA converter — map IPA Unicode phonetic symbols to SAMPA/X-SAMPA ASCII codes and back, instantly in your browser. No upload, no account. How to use: 1. Choose direction: Pick IPA to SAMPA to turn Unicode phonetic symbols into ASCII, or SAMPA to IPA for the reverse. 2. Paste your transcription: Enter the IPA string or the SAMPA/X-SAMPA ASCII string you want to convert. 3. Read and copy: The converted transcription updates as you type. Click Copy to grab the result. FAQ: Q: What is SAMPA? A: SAMPA (Speech Assessment Methods Phonetic Alphabet) is a system that maps IPA symbols onto plain 7-bit ASCII characters. X-SAMPA extends it to cover the full IPA so phonetic transcriptions can be typed and emailed without special Unicode fonts. Q: How is X-SAMPA different from SAMPA? A: Original SAMPA was language-specific and only covered common European sounds. X-SAMPA generalises the scheme to the entire IPA chart, adding codes for clicks, ejectives and rarer vowels. This tool uses the widely adopted X-SAMPA mappings. Q: Why are some symbols left unchanged? A: If a character has no defined mapping in the table it is passed through unchanged so nothing is silently dropped. Stress marks, spaces and brackets are preserved as typed. Q: Is the conversion exact and reversible? A: Most core IPA symbols round-trip cleanly. A few IPA glyphs share an ASCII code or use diacritic combinations, so very complex transcriptions may need manual review after a round trip. Q: Is my text uploaded anywhere? A: No. The conversion runs entirely in your browser using a local lookup table, so nothing is sent to a server. #### Malay Jawi to Rumi Converter URL: https://geratools.com/malay-jawi-rumi-converter Transliterates Malay between Jawi (Arabic-based script) and Rumi (Latin-based script) using the Dewan Bahasa letter set, including the Malay-specific letters ca, nga, pa, ga, nya and va. Free and instant. How to use: 1. Choose a direction: Pick Rumi to Jawi, or Jawi to Rumi. 2. Enter your text: Type or paste Malay text in the source script. 3. Copy the result: The converted script appears instantly; click Copy to reuse it. FAQ: Q: What are Jawi and Rumi? A: Rumi is the Latin-alphabet script used for everyday Malay. Jawi is the older Arabic-based script, still used in religious, royal, and cultural contexts in Malaysia and Brunei. Q: Which Malay-specific letters are supported? A: The six augmented Jawi letters for Malay sounds are included: ca چ, nga ڠ, pa ڤ, ga ݢ, nya ڽ, and va ۏ, following the Dewan Bahasa dan Pustaka letter set. Q: Why is the result a transliteration, not perfect spelling? A: Jawi is partly vowel-defective: short vowels are often not written, and some words have conventional spellings. The tool produces a consistent phonetic transliteration, which may differ from the official spelling of some words. Q: How are digraphs handled? A: Multi-letter Rumi sequences like ng, ny, sy, kh, and gh are matched before single letters, so ng becomes ڠ rather than two separate letters. Q: Is my text uploaded? A: No. The conversion runs entirely in your browser with no network calls, so your text stays private. #### Negative Squared Letter Text URL: https://geratools.com/negative-squared-text Free negative squared letter text generator. Convert words into Unicode Enclosed Alphanumeric Supplement squared characters for bold, high-contrast bios, names and posts. How to use: 1. Type your text: Enter the words you want converted into the input box. 2. See the squared output: Each A-Z letter is replaced live with its negative squared box character, with lowercase upper-cased automatically. 3. Copy and paste: Press Copy and paste the boxed text into any Unicode-friendly app. FAQ: Q: Why is my text forced to uppercase? A: Unicode only defines negative squared characters for the uppercase letters A-Z (U+1F170 to U+1F189). There are no lowercase forms, so the tool upper-cases input before converting. Q: Can I square numbers and symbols? A: No. The negative squared set covers only the 26 capital letters. Digits, spaces and punctuation are left unchanged so the output stays readable. Q: Why do the letters look like emoji? A: These characters live in an emoji-adjacent block, so many platforms render them as colourful or filled squares. Appearance varies by device, but the underlying character is always the same. Q: Will it work in a bio or username? A: Often, yes — but some platforms restrict emoji-style characters in names. Because each glyph is a real code point, where it is allowed it survives copy-paste with its boxed look intact. #### One-Time Pad Simulator URL: https://geratools.com/one-time-pad Free one-time pad (OTP) simulator. Generates a cryptographically random key the exact length of your message using the browser crypto API, then XOR-encrypts to hex — the only cipher with proven perfect secrecy. Decrypt with the same key. Runs entirely in your browser. How to use: 1. Type your message and generate a key: Enter the plaintext, then click Generate key to create a cryptographically random key the exact length of your message's bytes. 2. Encrypt the message: The tool XORs each message byte with the matching key byte and shows the ciphertext as hex. Share the key separately and securely with the receiver. 3. Decrypt with the same key: Switch to decrypt, paste the hex ciphertext and the same key, and the original message is recovered byte for byte. FAQ: Q: Why is the one-time pad unbreakable? A: If the key is truly random, at least as long as the message, used only once and kept secret, then every possible plaintext of that length is equally likely given the ciphertext. The ciphertext reveals no information about the message — a property called perfect secrecy, proven by Claude Shannon in 1949. Q: How is the random key generated? A: This tool uses the browser's crypto.getRandomValues, a cryptographically secure random number generator, to produce one random byte for every byte of your message. The key is shown as hex so you can store and share it exactly. Q: What breaks the one-time pad in practice? A: Three mistakes destroy its security: reusing a key for more than one message, using a key shorter than the message, or using a key that is not truly random (such as a passphrase). Any of these turns it into an ordinary, breakable cipher. Q: How do I share the key safely? A: The key must reach the receiver over a channel separate from the ciphertext and must stay secret — for example handed over in person on a physical pad. Key distribution is the hard, unsolved part of the one-time pad and why it is rarely practical at scale. Q: Is this the same as the Vernam cipher? A: Yes. Gilbert Vernam patented the XOR stream cipher in 1919; when the key stream is random, single-use and as long as the message, it is the one-time pad. This simulator implements exactly that with a fresh random key per message. #### Persian Alphabet Reference URL: https://geratools.com/persian-alphabet-reference Displays all 32 Perso-Arabic letters in isolated, initial, medial, and final joining forms with transliteration. Search by name or sound and copy any form instantly in your browser. How to use: 1. Browse the table: Scroll the chart to see all 32 Persian letters listed with their names and transliteration. 2. Compare the four forms: Each row shows the isolated, initial, medial, and final shapes the letter takes depending on where it sits in a word. 3. Search and copy: Type a name or sound to filter the list, then click any glyph to copy it to your clipboard. FAQ: Q: How many letters are in the Persian alphabet? A: The Persian (Farsi) alphabet has 32 letters. It builds on the 28-letter Arabic script and adds four letters — پ (pe), چ (che), ژ (zhe), and گ (gaf) — for sounds that Arabic lacks. Q: Why does each letter have four forms? A: Persian uses a connected (cursive) script, so most letters change shape depending on their position. The isolated form stands alone, the initial form starts a word, the medial form sits in the middle, and the final form ends a connected run. Q: Which Persian letters never connect to the left? A: Seven letters — ا د ذ ر ز ژ و — are non-connecting on their left side. They have only isolated and final forms, so the next letter always starts fresh in its initial shape. Q: Is Persian written right to left? A: Yes. Persian text flows right to left, like Arabic and Urdu. Numbers within the text, however, are read left to right. Q: Is my input sent anywhere? A: No. The reference table and search run entirely in your browser. Nothing you type or copy is uploaded to a server. #### PII Detector & Redactor URL: https://geratools.com/pii-detector-redactor Scan pasted text for personal data — email addresses, UK/US phone numbers, National Insurance numbers, US SSNs, passport numbers, payment cards, and IP addresses — and replace each with a typed token like [EMAIL_1]. All regex runs locally; nothing is transmitted. Built for pre-share scrubbing and GDPR reviews. How to use: 1. Paste your text: Drop the document, log, or message you want to scrub into the input box. Scanning happens live as you type or paste. 2. Review the summary: See how many of each PII type were found — emails, phone numbers, card numbers, and more — so you can confirm the scrub caught what you expected. 3. Copy the redacted output: Each detected value is replaced by a stable typed token like [EMAIL_1]. Copy the redacted text and share it safely. FAQ: Q: What types of PII does it detect? A: It detects email addresses, IPv4 addresses, payment card numbers (Luhn-validated), UK National Insurance numbers, US Social Security numbers, 9-digit passport numbers, and UK/US phone numbers. Each distinct value gets a numbered token. Q: How are card numbers validated? A: Candidate card numbers (13–19 digits) are checked with the Luhn algorithm before being redacted, so random long numbers that fail the checksum are left alone. This cuts down on false positives from order IDs and reference numbers. Q: Why does the same email get the same token? A: Tokens are stable per value: every occurrence of a given email maps to [EMAIL_1], a different email maps to [EMAIL_2], and so on. This keeps the redacted text readable and lets you tell distinct people apart without exposing their data. Q: Will it catch every piece of personal data? A: No. Regex-based detection catches structured identifiers reliably but cannot reliably find free-text names, addresses, or context-dependent data. Always review the output by eye before sharing anything sensitive — treat the tool as a first pass, not a guarantee. Q: Is my text sent to a server? A: No. All pattern matching and redaction run entirely in your browser. Nothing is uploaded, logged, or stored, which is exactly why it is safe to use on confidential documents. #### Regional Indicator Symbol Converter URL: https://geratools.com/regional-indicator Convert plain text into Unicode Regional Indicator Symbols — the boxed-letter emoji used on Discord, Twitch and social bios. Maps A–Z to U+1F1E6–U+1F1FF and decodes them back to plain letters. How to use: 1. Type your text: Enter any text containing the letters A–Z into the input box. Case is ignored because regional indicators are caseless. 2. Read the converted output: Each Latin letter is replaced by its Regional Indicator Symbol; spaces, digits and punctuation pass through unchanged. 3. Copy or decode: Copy the boxed-letter result to paste into Discord or a bio, or switch to decode mode to turn indicators back into plain letters. FAQ: Q: What are Regional Indicator Symbols? A: They are 26 Unicode characters (U+1F1E6 to U+1F1FF) that render as boxed letters A–Z. They were designed so that two of them in sequence form a flag emoji, but on their own they display as decorative squared letters. Q: Why do two indicator letters sometimes turn into a flag? A: When two regional indicators spell a valid ISO 3166-1 country code, most platforms combine them into that country's flag. For example 🇺 + 🇸 becomes 🇺🇸. Single letters or invalid pairs stay as separate boxed letters. Q: Does case matter? A: No. There is only one Regional Indicator Symbol per letter, so both uppercase and lowercase input map to the same character. The output is always uppercase-style boxed letters. Q: Will this work on every platform? A: Rendering depends on the device font. Discord, iOS, Android and most browsers show the boxed letters or combined flags. Some older systems may show the letters as plain text or tofu boxes. Q: Can I get my original text back? A: Yes. Use decode mode and the tool maps each Regional Indicator Symbol back to its plain A–Z letter. Characters that are not indicators are left untouched. #### ROT18 Encoder/Decoder URL: https://geratools.com/rot18 Free ROT18 encoder and decoder — applies ROT13 to letters and ROT5 to digits at once, so alphanumeric text is fully rotated. Self-inverse and instant, running entirely in your browser. How to use: 1. Enter your text: Type or paste any text containing letters and digits into the input box. 2. Read the rotated output: Letters are shifted by 13 (ROT13) and digits by 5 (ROT5) simultaneously, with everything else unchanged. 3. Copy or decode: Click Copy to grab the result. To decode, paste the ciphertext back in — ROT18 is its own inverse. FAQ: Q: What is ROT18? A: ROT18 is the combination of two simple ciphers applied together: ROT13 rotates each letter by 13 positions, and ROT5 rotates each digit by 5 positions. The name comes loosely from 13 + 5. Q: Why is ROT18 self-inverse? A: Both halves are self-inverse. ROT13 rotates by half of 26 and ROT5 by half of 10, so applying each twice returns the original. That makes the whole ROT18 operation reversible with the exact same step — no separate decode mode is needed. Q: What characters does ROT18 change? A: Only A–Z, a–z and 0–9 are transformed. Letters use ROT13 (A↔N, B↔O, …) and digits use ROT5 (0↔5, 1↔6, …). Spaces, punctuation and other symbols pass through untouched. Q: How does it handle case? A: Case is preserved. Uppercase letters rotate to uppercase letters and lowercase to lowercase, so a capital G becomes a capital T and a lowercase g becomes a lowercase t. Q: Is ROT18 secure encryption? A: No. It has no key and a tiny, fixed mapping, so anyone who recognises it can reverse it instantly. Use ROT18 for puzzles, light obfuscation, or to hide spoilers, never for real secrets. #### Younger Futhark Rune Encoder URL: https://geratools.com/runic-younger-futhark Transliterates Latin letters into the 16 runes of the Viking Age long-branch Younger Futhark, the reduced runic alphabet used across Scandinavia from roughly 800 to 1100 AD. Maps overlapping sounds to shared runes. Runs in your browser. How to use: 1. Type your text: Enter Latin text and the tool transliterates each sound to its closest Younger Futhark rune. 2. Read the runes: The runic output appears using real Unicode runic characters, with several Latin letters sharing one rune by sound. 3. Copy the runes: Use the copy button to paste the runic transliteration into documents that support the Unicode Runic block. FAQ: Q: What is Younger Futhark? A: Younger Futhark is the reduced runic alphabet used across Scandinavia during the Viking Age, roughly 800 to 1100 AD. It shrank the older 24-rune Elder Futhark down to just 16 runes, so a single rune often represented several related sounds. Q: Why do different letters produce the same rune? A: Sixteen runes cannot cover every Latin sound, so the script merged distinctions. The same rune served voiced and unvoiced pairs and similar vowels: B and P share one rune, T and D share another, and the same rune covers U, O, V, W, and Y. This faithfully reflects how Younger Futhark was actually written. Q: Which variant does this tool use? A: It uses the long-branch (Danish) Younger Futhark, the most widely attested form, rendered with the standard Unicode Runic block. The short-twig (Swedish-Norwegian) variant uses different glyph shapes for some runes but the same sound system. Q: Is this a reversible cipher? A: Not perfectly. Because several Latin letters collapse onto one rune, you cannot always recover the exact original spelling from the runes alone. Transliteration back to Latin requires context, just as it did for medieval readers. Q: Will the runes display on my device? A: The runes use the Unicode Runic block (U+16A0 to U+16FF). Most modern systems include a font that covers it, but on older devices some runes may appear as empty boxes if no runic-capable font is installed. #### Speech to Text Dictation URL: https://geratools.com/speech-to-text-dictation Free speech to text dictation in your browser. Speak and watch your words appear in real time, in a dozen languages, then edit, copy or download the transcript. Uses the built-in Web Speech API — Gera never sees your audio or text. How to use: 1. Choose a language: Pick the language you will speak from the drop-down so recognition matches your accent and vocabulary. 2. Start dictating: Press Start dictation, allow microphone access, and speak clearly. Your words appear in the box as you talk. 3. Edit and export: Fix any words directly in the text box, then copy the transcript or download it as a .txt file. FAQ: Q: How does browser speech to text work? A: It uses the Web Speech API built into modern browsers. When you dictate, the browser converts your speech to text and streams the words back to the page in real time, where you can edit, copy or download them. Q: Does Gera see or store my voice? A: No. The recognition is performed by your browser and operating system. On Chrome and Safari the browser vendor processes the audio through its own speech service, exactly as your device's built-in dictation does. Gera Tools never receives, stores or transmits your audio or transcript — the text lives only in your browser tab. Q: Which languages are supported? A: The tool offers English (US and UK), Spanish, French, German, Italian, Portuguese, Hindi, Arabic, Chinese, Japanese and Russian. Available languages ultimately depend on your browser and operating system. Q: Why does dictation stop or miss words? A: Recognition works best with a good microphone, a quiet room and clear, steady speech. Background noise, a weak connection, or speaking too fast can cause dropped words. The tool automatically restarts listening if the browser pauses it mid-session. Q: Which browsers support this? A: The Web Speech API is supported in recent versions of Chrome, Edge and Safari. If your browser does not support it, the tool shows a message; try one of those browsers instead. #### Swahili Noun Class Reference URL: https://geratools.com/swahili-noun-class-reference A filterable reference of the Swahili (Kiswahili) noun-class system — M-/WA-, M-/MI-, KI-/VI-, JI-/MA-, N-/N-, U-, KU- and the locatives — with noun prefixes, subject and object concords, and examples. Runs in your browser. How to use: 1. Browse the class table: Scan the full list of Swahili noun classes with their prefixes and agreement markers. 2. Filter to what you need: Type a prefix, class number, or meaning to narrow the table to matching classes. 3. Copy a concord: Click any row to copy its subject concord for use in conjugating a verb. FAQ: Q: What is a Swahili noun class? A: Swahili sorts every noun into a class, similar to grammatical gender but with many more categories based on meaning and prefix shape. Classes usually come in singular and plural pairs, such as M-/WA- for people and KI-/VI- for things, and they control agreement across the sentence. Q: What are subject and object concords? A: A concord is the agreement marker a noun class triggers on other words. The subject concord goes at the front of the verb to agree with the subject, and the object concord is infixed to agree with the object. For class 2 these are wa- and -wa-. Q: Why are some class numbers missing? A: The reference uses the traditional Bantu numbering 1 to 18. Some proto-Bantu classes, such as 12 and 13, are not productive in standard Swahili and class 11 merges its plural into class 10, so the table lists the classes that are actually used in Kiswahili. Q: What are the locative classes 16, 17 and 18? A: Locatives express place using the suffix -ni plus distinct concords: class 16 (pa-) for a definite spot, class 17 (ku-) for general or indefinite location, and class 18 (mu-) for being inside something, as in nyumbani for in the house. Q: Does anything leave my browser? A: No. The reference table and filtering run entirely in your browser. Nothing you type is uploaded or stored. #### Swahili Tense Marker Reference URL: https://geratools.com/swahili-tense-marker-reference Shows all Swahili tense/aspect markers (present na-, past li-, future ta-, perfect me-, conditional nge-/ngali-) with example verb conjugations you build from any stem. How to use: 1. Enter a verb stem: Type a Swahili verb root such as -soma (read) or -penda (love), with or without the leading hyphen. 2. Pick a subject: Choose the subject prefix (ni- I, u- you, a- he/she, tu- we…) to set who performs the action. 3. Read the conjugations: The table builds the full verb for each tense marker — subject + tense + stem — with its English meaning. FAQ: Q: How is a Swahili verb built? A: A Swahili verb in basic tenses follows the order subject prefix + tense marker + verb stem. For example ni- (I) + -na- (present) + -soma (read) gives ninasoma, 'I am reading'. Q: What is the difference between -li- and -me-? A: -li- is the simple past ('I read', a completed event), while -me- is the perfect, marking a present-relevant result ('I have read'). Nimekula means 'I have eaten' and so 'I am full', whereas nilikula simply states the past act of eating. Q: What does the -ka- marker do? A: -ka- is the consecutive or narrative marker. It chains actions that happen one after another, usually after an initial -li- past verb, so it often translates as 'and then'. It is the backbone of storytelling in Swahili. Q: Does the subject prefix change before some tense markers? A: Yes. The third-person singular subject a- merges with the present -na- to give ana-, and the negative forms use different subject prefixes (si-, hu-, ha-). The reference shows the standard affirmative forms. Q: How do you make a present-tense verb negative? A: Negation in the present uses a special pattern: the negative subject prefix plus the stem with its final -a changed to -i, dropping -na- entirely. So ninasoma ('I read') becomes sisomi ('I do not read'). #### Tap Code Dot Visualiser URL: https://geratools.com/tap-code-dots Free tap code visualiser — converts text into the 5x5 Polybius knock cipher and renders each letter as two groups of dots, the way prisoners actually tapped it out. Runs entirely in your browser. How to use: 1. Type your message: Enter the text you want to convert. Letters are read case-insensitively and C and K share one cell. 2. Read the dot grids: Each letter shows two groups of dots — the first group is the row, the second is the column of the tap code grid. 3. Tap or copy: Use the visual dots to tap out the message, or copy the numeric row-column pairs to share digitally. FAQ: Q: What is tap code? A: Tap code is a way of encoding letters as taps using a 5x5 Polybius square. Each letter is sent as two short bursts of taps: the first counts the row and the second counts the column. Q: Why are there only 25 cells for 26 letters? A: The 5x5 grid holds 25 letters, so C and K share the same cell. When decoding, readers infer from context whether a C or K was meant. Q: How do I read the dots? A: Count the dots in the first group to find the row (1 to 5), then count the dots in the second group for the column. Row 4, column 4 is the 19th cell, which is T. Q: Where was tap code famously used? A: American prisoners of war in Vietnam used tap code to communicate between cells by knocking on walls, because it needs no equipment and is easy to learn and overhear-resistant. Q: Is my text uploaded anywhere? A: No. The entire conversion happens locally in your browser and nothing is sent to any server. #### Tap Code Encoder/Decoder URL: https://geratools.com/tap-code Free tap code (knock code) encoder and decoder. Maps each letter to two groups of taps giving its row and column on a 5×5 Polybius grid (C and K share a cell), and decodes tap groups back to text. The cipher famously used by prisoners of war. Runs entirely in your browser. How to use: 1. Choose encode or decode: Encode turns letters into tap groups; decode turns tap groups back into letters. Each letter is two numbers, the row and the column. 2. Enter your text: Type a message to encode, or paste tap groups (for example "dot patterns" or numbers) to decode. The letter K is mapped onto C. 3. Read the result: Encoding shows each letter as taps for its row and column; decoding reconstructs the plaintext from the tap pairs. FAQ: Q: What is the tap code? A: The tap code, or knock code, is a way to send letters by tapping. It arranges 25 letters in a 5×5 grid and represents each letter by tapping its row number, a short pause, then its column number. It was famously used by American prisoners of war in Vietnam to communicate between cells. Q: Why is there no letter K? A: A 5×5 grid holds only 25 cells but the alphabet has 26 letters, so one letter is dropped. In the standard tap code the letter K is omitted and senders use C in its place; when decoding, a C in a word that should contain K is read in context. Q: How are the taps grouped? A: Each letter is two numbers. The first group of taps is the row (1-5) and the second group is the column (1-5). For example the letter R is row 4, column 2, so it is tapped as four taps, pause, two taps. Q: How does this tool show the taps? A: The encoder shows each letter as two groups of dot characters separated by a small gap, with a larger gap between letters, mirroring the tap-pause-tap rhythm. The decoder accepts dot groups or plain numbers like 4 2 and converts them back to letters. Q: Is the tap code secure? A: No. It is just a Polybius-square encoding with no secret key, so anyone who knows the grid can read it. Its purpose was covert hand-to-hand signalling, not cryptographic secrecy, and it is trivial to decode once recognised. #### Telephone Keypad T9 Encoder URL: https://geratools.com/telephone-keypad Converts text into the multi-tap key presses used on a classic mobile phone keypad, where A is one press of 2, B is two presses, C is three presses, and so on across the ITU E.161 layout. Runs in your browser. How to use: 1. Type your message: Enter the text you want to convert into phone key presses; letters are mapped to the standard 2-to-9 keypad. 2. Read the press sequence: Each letter becomes a digit repeated by how many times you tap it, like 7777 for S, separated by spaces. 3. Copy the code: Use the copy button to grab the full multi-tap sequence for puzzles, retro texting, or teaching. FAQ: Q: Which keypad layout does this use? A: It uses the standard ITU-T E.161 layout found on mobile phones: 2 holds ABC, 3 holds DEF, 4 GHI, 5 JKL, 6 MNO, 7 PQRS, 8 TUV, and 9 WXYZ. Keys 7 and 9 have four letters each. Q: How are press counts shown? A: A letter is written as its digit repeated once per tap. A is 2, B is 22, C is 222, and S is 7777. This multi-tap notation is unambiguous because the repetition count identifies the exact letter. Q: What happens to spaces and digits? A: On real phones a space is the 0 key, so spaces are shown as 0. Digits 0 to 9 are passed through as themselves, and any other character such as punctuation is left unchanged. Q: How is this different from ambiguous T9? A: Ambiguous T9 writes only the digit once per letter, so 2 could mean A, B, or C and software guesses the word. This multi-tap version repeats the digit by tap count, so each letter is uniquely recoverable without a dictionary. Q: Is letter case preserved? A: No. Phone keypads have no case, so all letters are treated case-insensitively and mapped to the same key sequence whether they were typed in uppercase or lowercase. #### Text 3-Way Merge URL: https://geratools.com/text-3way-merge Free 3-way text merge tool that takes a common base plus two diverged versions and produces a merged result in your browser, auto-applying non-conflicting changes and marking real conflicts with Git-style markers. Nothing is uploaded. How to use: 1. Paste the base and two versions: Paste the common ancestor in the Base box, then the two diverged edits in the A (mine) and B (theirs) boxes. All three are compared line by line. 2. Let the tool merge: Lines changed in only one side are applied automatically. Where both sides changed the same region differently, a conflict block is produced. 3. Resolve conflicts: Each conflict shows the A and B text with Git-style markers; pick one side or edit the merged output directly, then copy the result. FAQ: Q: What is a 3-way merge? A: A 3-way merge combines two versions of a file using their common ancestor (the base) as a reference. By comparing each side against the base, the algorithm can tell whether a change came from A, from B, or from both — which a simple 2-way diff cannot. This is exactly how Git merges branches. Q: When does a conflict happen? A: A conflict occurs when the same region of the base was changed differently by both A and B. If only one side touched a region, that side's version is taken automatically. If both made the identical change, there is no conflict — the shared result is used. Q: What do the conflict markers mean? A: Conflicts are wrapped in Git-style markers: the lines after the opening marker are version A, the lines after the divider are version B, and the closing marker ends the block. Editing the output to keep one side and delete the markers resolves the conflict. Q: How are lines compared? A: The tool splits each input into lines and runs a longest-common-subsequence diff of each side against the base, then walks the two diffs together to assemble stable regions, one-sided changes and conflicts. Whitespace and blank lines are treated as ordinary content. Q: Is my text uploaded anywhere? A: No. The entire merge runs in your browser in plain JavaScript. No text is transmitted, so the tool works offline and your content stays private. #### English to IPA Transcriber URL: https://geratools.com/text-to-ipa Free English-to-IPA transcriber — look up common English words in a CMU-derived pronouncing dictionary and get broad General-American IPA. Runs in your browser. How to use: 1. Type English text: Enter the words you want transcribed into the text box. 2. Read the IPA: Each recognised word is replaced by its broad IPA transcription in real time. 3. Copy the result: Click Copy IPA to grab the full transcription for use elsewhere. FAQ: Q: Where do the transcriptions come from? A: They come from a subset of the Carnegie Mellon University Pronouncing Dictionary, converted to IPA symbols. The dictionary covers the most common English words used in everyday writing. Q: What happens to words not in the dictionary? A: Words that are not found are shown unchanged inside square brackets, for example [photosynthesis]. This makes it clear which words were transcribed and which were left alone. Q: Which accent does it use? A: The transcriptions follow General American pronunciation, which is what the CMU dictionary is based on. British (RP) speakers will notice differences such as rhotic r sounds. Q: Is the transcription narrow or broad? A: It is broad, also called phonemic, transcription. It captures the distinctive sounds of each word without marking fine phonetic detail like aspiration or vowel length. Q: Is my text uploaded anywhere? A: No. The lookup runs entirely in your browser against a built-in dictionary, so nothing is sent to a server. #### Thai Kedmanee Keyboard Reference URL: https://geratools.com/thai-keyboard-reference Displays the Thai Kedmanee keyboard layout overlaid on a QWERTY board, showing which Thai character each key produces in both the normal and shifted state. How to use: 1. Find a key: Look at the keyboard grid to see the Thai character on each physical QWERTY key, both unshifted and shifted. 2. Search for a character: Type a Thai character or its key letter to highlight where it lives on the Kedmanee layout. 3. Practice typing: Use the map to learn finger positions for common Thai consonants and vowels on the standard Thai keyboard. FAQ: Q: What is the Kedmanee layout? A: Kedmanee is the standard Thai keyboard layout, the one shipped on virtually all Thai computers and phones. It places Thai characters on the physical QWERTY keys, with two characters per key accessed normally and with Shift. Q: Why are there two characters on each key? A: Thai has far more characters than there are keys, so each key carries one character in its normal state and another when Shift is held. The unshifted layer holds the most frequent consonants and vowels; less common characters and tone marks sit on the shifted layer. Q: Is Kedmanee the same as Pattachote? A: No. Pattachote is an alternative Thai layout designed for faster typing and more even hand balance, but it never became popular. Kedmanee is by far the more widespread standard, which is why this reference uses it. Q: Where are the tone marks on the keyboard? A: The four tone marks sit mostly on the number-row and home-row keys, several on the shifted layer. Because they are combining marks, you type the base consonant and vowel first and add the tone mark afterward. Q: Does this match my phone's Thai keyboard? A: Phone keyboards rearrange keys for touch and often hide the shifted layer behind a long-press, but the character set is the same Kedmanee standard. The desktop grid shown here is the canonical reference for which character maps to which letter. #### Thai Tone Rule Explainer URL: https://geratools.com/thai-tone-rule-checker For each Thai syllable typed, determines which of the five tones applies based on initial consonant class, vowel length, final consonant (live or dead), and any tone mark. How to use: 1. Type a Thai syllable: Enter a single Thai syllable using the on-screen analysis, or paste one from another source. 2. Read the factors: The tool identifies the initial consonant class, whether the syllable is live or dead, the vowel length, and any tone mark. 3. See the resulting tone: Based on those factors the tool reports which of the five Thai tones applies and explains the rule used. FAQ: Q: What determines a Thai syllable's tone? A: Four things combine: the class of the initial consonant (high, mid, or low), whether the syllable is live or dead, the length of the vowel, and any tone mark written above it. Thai has no separate 'tone letters' — the tone is computed from these features. Q: What are the three consonant classes? A: Thai consonants fall into mid (กจดตบปอ and others), high (ขฉฐถผฝศษสห), and low (the remaining majority) classes. The class of the initial consonant is the starting point for every tone calculation. Q: What is the difference between a live and dead syllable? A: A live syllable ends in a long vowel or a sonorant final (ม น ง ย ว). A dead syllable ends in a short vowel with no final, or in a stop final (ก ด บ and their spellings). Dead syllables behave differently in the tone rules. Q: How do tone marks change the tone? A: The four tone marks (mai ek ่, mai tho ้, mai tri ๊, mai chattawa ๋) override the default tone, but their effect still depends on the consonant class. For example mai ek on a mid-class initial gives low tone, while on a low-class initial it gives falling tone. Q: Is my input uploaded? A: No. The analysis runs entirely in your browser using the standard Thai tone rules. Nothing you type is sent anywhere. #### Latin Transliterator URL: https://geratools.com/transliterate-latin Transliterate text from Cyrillic, Greek, and Armenian scripts into the Latin alphabet using standard romanisation tables. Useful for names, place names, and search. Runs entirely in your browser. How to use: 1. Choose the source script: Select the script your text is written in, such as Cyrillic, Greek, or Armenian. 2. Paste your text: Type or paste the non-Latin text you want romanised into the input box. 3. Read the Latin output: The transliterated Latin version appears instantly below, ready to copy. FAQ: Q: What is transliteration? A: Transliteration maps the letters of one script onto the closest letters of another, so the result can be read aloud roughly the same way. It is different from translation, which conveys meaning rather than sound. Q: Which scripts are supported? A: This tool covers Russian Cyrillic, modern Greek, and Eastern Armenian using widely used romanisation conventions. Each script has its own letter-by-letter mapping table applied in order from longest match to shortest. Q: Is the romanisation standardised? A: It follows common practical romanisation close to ISO and BGN/PCGN conventions, favouring readable Latin output. Official documents may require a specific standard, so always check the rules for passports or legal use. Q: Why do some letters map to two Latin letters? A: Single characters in Cyrillic or Greek often represent sounds that need a digraph in Latin, such as the Cyrillic ch, sh, and ya, or the Greek theta and chi. The table emits multiple Latin letters where one would lose the sound. #### Turkish Vowel Harmony Checker URL: https://geratools.com/turkish-vowel-harmony-checker Check a Turkish word for backness vowel harmony and flag any vowel that breaks the front or back series. Useful for testing suffix chains and spotting loanwords that violate the rule. How to use: 1. Enter a Turkish word: Type a word or suffix chain you want to test into the input field. 2. Read the verdict: The tool lists the vowels and says whether the word is harmonious or flags violations. 3. Inspect violations: Any vowel that breaks the series is listed with its position and the expected group. FAQ: Q: What is backness vowel harmony? A: Backness (büyük ünlü uyumu) means all vowels in a native Turkish word share the same backness. Front vowels (e, i, ö, ü) group together, and back vowels (a, ı, o, u) group together. The checker compares each vowel against the first. Q: How does the tool decide if a word is harmonious? A: It takes the backness of the first vowel as the baseline. Every following vowel must match that group. If any vowel differs, the word is flagged with the position and the group it should have matched. Q: Why do words like kitap fail the check? A: Loanwords often break harmony. kitap mixes the back vowel i-like a with i, and otobüs mixes back and front vowels. These are legitimate Turkish words borrowed from other languages, so a flag here is expected, not an error. Q: Does it check rounding (small) vowel harmony too? A: No. This tool checks backness harmony only, the most fundamental rule. Rounding harmony (küçük ünlü uyumu), which governs suffix vowel rounding, is a separate constraint not evaluated here. Q: What about single-vowel or vowel-less words? A: A word with one vowel is trivially harmonious, and a word with no vowels has nothing to check. The tool notes both cases instead of flagging them. #### Ubbi Dubbi Transformer URL: https://geratools.com/ubbi-dubbi Free Ubbi Dubbi translator that inserts 'ub' before each vowel sound and decodes it back, recreating the secret language from PBS's Zoom, entirely in your browser. How to use: 1. Choose encode or decode: Pick whether to add 'ub' before vowels or strip it back out. 2. Enter your text: For encoding, type normal text. For decoding, type Ubbi Dubbi text. 3. Read and copy the result: The output updates instantly. Click Copy to grab it. FAQ: Q: What is Ubbi Dubbi? A: Ubbi Dubbi is a language game popularised by the 1970s PBS children's show Zoom. You speak it by inserting the sound 'ub' before every vowel sound in a word. Q: What counts as a vowel sound? A: Each vowel letter (a, e, i, o, u) is treated as a vowel sound and gets 'ub' inserted in front of it. Consecutive vowels are each prefixed, matching the simple letter-based rule most players use. Q: How do I decode it? A: Switch to decode mode and the tool removes every 'ub' that immediately precedes a vowel, reversing the transformation to recover the original text. Q: Does it preserve capitalisation? A: Yes. When a capital vowel is prefixed, the capital is carried onto the inserted 'Ub' so 'Apple' reads naturally as 'Ubapplube'-style output without losing the original case. Q: Is my text uploaded anywhere? A: No. The transformation runs entirely in your browser and nothing is sent to a server. #### UwU Text Transformer URL: https://geratools.com/uwu-transform Convert any text into UwU speak: swap r/l for w, turn th into d, add ny before vowels, and sprinkle stutters and kaomoji faces. Deterministic, runs in your browser, free and keyless. Owo what's this? How to use: 1. Type your text: Enter the sentence or message you want to UwU-ify. 2. See the transform: The tool swaps letters, inserts ny before vowels, and adds occasional stutters and faces for cuteness. 3. Copy the result: Click Copy and paste the UwU text into chat, a caption, or a comment. FAQ: Q: What changes does it make? A: It replaces r and l with w, turns th into d, inserts a y after an n that precedes a vowel (na becomes nya), and randomly adds first-letter stutters and kaomoji faces like owo and UwU. Q: Is the output random each time? A: No. The stutters and faces are chosen with a deterministic hash of each word, so the same input always produces the same UwU output. That makes it easy to reproduce a result. Q: Does it keep capitalisation? A: Mostly. Letter swaps respect case (R becomes W, r becomes w), and the inserted ny matches the case of the original n. Faces and stutters are added around words without altering their letters. Q: Where do people use UwU text? A: It is an internet meme style popular in Discord servers, Twitch chat, social captions, and gaming communities. It is meant to be playful and cute, never serious. Q: Does my text get sent anywhere? A: No. The transform is pure JavaScript running in your browser, so your input never leaves the page and works offline once loaded. #### WebVTT to SRT Converter URL: https://geratools.com/vtt-to-srt Convert WebVTT (.vtt) captions to SubRip (.srt): strips the WEBVTT header and NOTE, STYLE and REGION blocks, removes cue settings, rewrites dot millisecond separators to commas, expands short timestamps and renumbers cues. Browser-only — subtitles stay on your device. How to use: 1. Load or paste your VTT: Upload a .vtt file or paste the WebVTT text. The converter reads it locally and skips the header and any metadata blocks. 2. Review the SRT output: The tool reports how many cues converted and previews the SubRip output with comma timestamps and sequential numbering. 3. Download or copy the .srt: Download a subtitles.srt for media players and editors that prefer SubRip, or copy the SRT text to your clipboard. FAQ: Q: What does the converter strip out? A: It removes the WEBVTT header line and any header metadata, plus NOTE, STYLE and REGION blocks, which have no SubRip equivalent. Cue positioning settings after the timestamps are also dropped because SubRip does not support them. Q: How are timestamps changed? A: WebVTT uses a dot before milliseconds and may omit the hours field (00:04.000). The converter switches the dot to a comma and expands short timestamps to the full hh:mm:ss,ms form that SubRip requires. Q: What happens to voice and class tags? A: WebVTT voice tags and class tags have no SubRip counterpart, so their wrappers are removed while the spoken text inside them is kept. Basic styling like italics passes through unchanged. Q: Does it renumber the cues? A: Yes. SubRip requires a sequential numeric index above every cue, so the converter discards any WebVTT cue identifiers and renumbers from 1 in order. Q: Is my file uploaded? A: No. The whole conversion happens in your browser. Your subtitle file is never sent to a server, so private or pre-release captions stay on your device. #### Wingdings-Style Symbol Mapper URL: https://geratools.com/wingdings-style Free Wingdings-style symbol mapper. Convert text into a decorative cipher of thematic Unicode dingbats and symbols that render on every device — no proprietary Wingdings font required. Runs entirely in your browser. How to use: 1. Type your text: Enter any word or phrase in the input box. Each letter and digit is replaced with a thematic Unicode symbol as you type. 2. Review the symbols: The output box shows the symbol version at a larger size so the dingbats are easy to read and compare. 3. Copy the result: Click Copy to grab the symbol string and paste it into a chat, puzzle, or design that supports Unicode. FAQ: Q: Is this the real Wingdings font? A: No. Wingdings is a proprietary Microsoft font, and its glyphs only appear if that exact font is installed and applied. This tool instead maps each letter to a standard Unicode dingbat or symbol with a similar theme, so the result renders and copies correctly on any device. Q: How are letters chosen for each symbol? A: Each letter maps to a fixed, thematically chosen Unicode symbol — for example H to a heart and Z to a lightning bolt. It is a one-to-one substitution cipher, so the same letter always produces the same symbol, making it reversible by anyone with the key. Q: Can the symbols be decoded back to text? A: Because the mapping is one-to-one and fixed, anyone using the same chart can decode it by hand. This tool focuses on encoding; the substitution is meant for fun, puzzles, and decoration rather than secure encryption. Q: Why do spaces and some characters stay the same? A: Only letters, digits, and a few common symbols have a mapping. Spaces, punctuation, and any unmapped character pass through unchanged so word boundaries and structure remain visible. Q: Is my text uploaded anywhere? A: No. The substitution runs locally in your browser with JavaScript. Nothing you type is sent to a server, logged, or stored. #### Palindrome Checker URL: https://geratools.com/palindrome-checker Free palindrome checker — test whether a word, phrase or sentence reads the same forwards and backwards, with options to ignore case, spaces and punctuation. Runs entirely in your browser, nothing is uploaded. How to use: 1. Type your text: Enter a word, phrase or sentence to test. 2. Set the matching rules: Choose whether to ignore case and whether to ignore spaces and punctuation. 3. Read the verdict: The result instantly shows whether the text is a palindrome. FAQ: Q: Can it handle phrases like "A man, a plan, a canal: Panama"? A: Yes — enable ignore spaces and punctuation, and it will detect classic phrase palindromes by comparing only the letters and numbers. Q: Does it work with accented and non-Latin letters? A: Yes — it uses Unicode-aware comparison so accented characters and other scripts are handled correctly. Q: What exactly is a palindrome? A: A palindrome is a sequence — a word, number or phrase — that reads identically forwards and backwards, such as "level", "racecar" or "12321". Q: What does "ignore case" do? A: It lowercases the whole string before comparing, so "Madam" counts as a palindrome even though the capital M and lowercase m differ. Q: What does "ignore spaces and punctuation" do? A: It strips everything except letters and numbers before reversing the text, so spaces, commas, colons and other marks do not break a phrase palindrome like "Was it a car or a cat I saw?". Q: Is an empty box a palindrome? A: No. With nothing left to compare the tool reports no palindrome rather than a trivial yes, so you always get a meaningful verdict. Q: Is my text sent anywhere? A: No — the check runs entirely in your browser and nothing is uploaded. #### Words to Number Converter URL: https://geratools.com/words-to-number-converter Free words-to-number converter. Type a number spelled out in English — "two hundred fifty thousand" or "one lakh fifty thousand" — and get the digits back. Supports Western and Indian scale words. Runs entirely in your browser; nothing is uploaded and your text never leaves your device. How to use: 1. Type the number in words: Enter a number spelled out in English, e.g. "one hundred twenty-three thousand". Hyphens, commas and the words "and"/"only" are ignored. 2. Read the digits: The numeric value appears instantly, both grouped with thousands separators and as a plain number. 3. Copy the result: Use the Copy button to put the digits on your clipboard. FAQ: Q: Which scale words are supported? A: Units and tens (one to ninety-nine), plus hundred, thousand, lakh/lac, million, crore, billion/arab and trillion. Western and Indian systems both work, so "one lakh fifty thousand" and "one hundred fifty thousand" both resolve. Q: Does it handle Indian lakh and crore? A: Yes. It recognises lakh (and the spelling lac) and crore, so "one crore" gives 10000000 and "five lakh" gives 500000, alongside the Western thousand, million, and billion. Q: Are hyphens, commas and the word "and" a problem? A: No. Hyphens, commas, and filler words like "and" and "only" are ignored, so "twenty-five thousand and fifty only" parses the same as "twenty five thousand fifty". Q: What happens with an unrecognised word? A: Rather than silently ignoring it, the converter reports the first word it cannot recognise, so you can correct unusual phrasing instead of trusting a wrong answer. Q: Does it show the number with separators? A: Yes. The result appears both grouped with thousands separators for readability and as a plain run of digits you can copy with one click. Q: Why convert words to numbers? A: It is useful for transcribing amounts on cheques, invoices, and contracts, double-checking spelled-out figures, and turning dictated or spoken numbers into digits accurately. Q: Is my text sent anywhere? A: No. All parsing happens locally in your browser using JavaScript. Your text is never uploaded, stored or transmitted — it stays entirely on your device. #### Anagram Solver & Checker URL: https://geratools.com/anagram-solver Free anagram tool that checks whether two words or phrases are anagrams and lists every distinct rearrangement of a set of letters. Runs entirely in your browser — nothing is uploaded. How to use: 1. Pick a mode: Choose Check to compare two words, or Rearrange to list every ordering. 2. Enter your letters or words: Type the two words to compare, or the letters you want to rearrange. 3. Read the result: See an instant yes/no answer, or scroll the full list of arrangements. FAQ: Q: How does the anagram check work? A: It compares the letters of each input ignoring spaces, punctuation and case. If both contain exactly the same letters, they are anagrams — so "listen" and "silent" match. Q: Does the rearranger find real dictionary words? A: No — it lists every distinct ordering of your letters and does not download a word list, so it includes non-words. Use it as a starting point for spotting valid words yourself. Q: Why is there an 8-letter limit on rearranging? A: The number of arrangements grows factorially, so beyond 8 letters the list becomes too large to display usefully. The checker mode has no length limit. Q: What is a famous example of an anagram? A: The words listen and silent are a classic pair — they use exactly the same six letters. Dormitory and dirty room is another well-known phrase anagram once spaces are ignored. Q: How many arrangements do n letters have? A: A set of n distinct letters has n factorial (n!) orderings — for example 4 letters give 24 and 6 letters give 720. Repeated letters reduce the number of distinct arrangements. #### Words to Pages Calculator URL: https://geratools.com/words-to-pages-calculator Estimate how many pages your word count fills, by line spacing and font size. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter your word count: Type or paste the number of words in your document. 2. Choose spacing and font: Pick single, 1.5 or double line spacing and your font size. 3. Read the page estimate: The estimated page count updates instantly below. FAQ: Q: How many words is one page? A: A common academic benchmark for 12pt Times New Roman with 1-inch margins is about 500 words per single-spaced page, 375 for 1.5 spacing and 250 for double spacing. Q: How many pages is 1000 words? A: At 12pt, roughly 2 pages single-spaced or 4 pages double-spaced. A 2000-word essay is about 4 pages single-spaced or 8 double-spaced. Q: How does font size change the page count? A: The estimate scales inversely with font size relative to the 12pt baseline. A larger font fits fewer words per page (more pages); a smaller font fits more (fewer pages). Q: Does line spacing affect the result? A: Yes. Double spacing roughly halves the words per page compared with single spacing, so a double-spaced document needs about twice as many pages for the same word count. Q: Why is the result an estimate? A: Real page counts depend on font, margins, headings, lists and images, so this gives a close approximation rather than an exact figure. Q: Is my text uploaded anywhere? A: No — you only enter a number, and every calculation runs in your browser. #### Text to PDF Converter URL: https://geratools.com/text-to-pdf Free text-to-PDF converter. Paste plain text or Markdown, choose font, size, margins and page format, then download a properly paginated PDF. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste or type your text: Drop plain text or Markdown into the editor. Toggle "Parse Markdown" on to render headings, lists, bold, italic, quotes and code. 2. Choose the layout: Pick a font, body size, line spacing, margin and page size (A4, Letter, Legal or A5), and switch to landscape if you need it. 3. Download the PDF: Click Download PDF. The tool paginates your content, adds optional page numbers, and saves the file straight to your device. FAQ: Q: Does my text get uploaded to a server? A: No. Everything happens locally in your browser using JavaScript. Your text never leaves your device, which makes this safe for confidential notes, contracts or drafts. Q: Can it convert Markdown to PDF? A: Yes. Turn on the "Parse Markdown" toggle and the tool renders headings, ordered and unordered lists, bold and italic text, inline code, fenced code blocks, blockquotes and horizontal rules into a styled PDF. Q: Which page sizes and fonts are supported? A: You can choose A4, US Letter, US Legal or A5, in portrait or landscape. Fonts include Helvetica (sans-serif), Times (serif) and Courier (monospace), each with adjustable size and line spacing. Q: Will long documents paginate correctly? A: Yes. The layout engine measures every line and starts a new page when content reaches the bottom margin, so paragraphs, list items and headings flow across as many pages as needed without being cut off. Q: Can I add page numbers and a document title? A: Yes. Tick "Page numbers" to print a centred page count in the footer of every page, and set a document title that is embedded in the PDF metadata. Q: How is justified text handled? A: Choose "Justified" alignment and the tool distributes extra space between words so each full line reaches the right margin, while the final line of a paragraph stays left-aligned for a natural finish. #### Markdown Table Editor URL: https://geratools.com/markdown-table-editor Free visual Markdown table editor. Type into a spreadsheet-style grid, set per-column alignment, sort, import Markdown/CSV/TSV, then copy or download a clean GitHub-flavoured table. 100% in your browser. How to use: 1. Edit cells in the grid: Click any header or cell and type. The Markdown output at the bottom updates live as you edit. 2. Add, move and align columns: Use the +Row and +Column buttons, the per-row and per-column arrows to reorder, and the alignment button to cycle a column between left, centre and right. 3. Import or paste existing data: Paste a Markdown table, CSV or TSV into the import box (format is auto-detected), or paste a spreadsheet selection straight into a cell to fill the grid. 4. Copy or download the result: Copy the generated GitHub-flavoured Markdown to your clipboard, or download it as a .md or .csv file. FAQ: Q: What is a GitHub-flavoured Markdown table? A: GitHub-Flavoured Markdown (GFM) renders a table from pipe-separated rows and a divider line of dashes. The header row sits on top, a second row of dashes (optionally with colons for alignment) defines the columns, and each following row is one record. This editor always outputs valid GFM that renders on GitHub, GitLab, Obsidian, Notion and most static-site generators. Q: How do I set column alignment? A: Click the alignment button above any column to cycle it through left, centre and right. The editor encodes that as colons in the divider row — a leading colon means left, colons on both sides mean centre, and a trailing colon means right — and previews the alignment live in the grid. Q: Can I import a CSV or an existing Markdown table? A: Yes. Open the import panel and paste a Markdown table, CSV or TSV — the format is detected automatically, including comma, semicolon and tab delimiters with quoted fields. You can also import a .csv, .tsv or .md file, or paste a spreadsheet selection directly into a cell to expand the grid. Q: How are pipe characters and line breaks handled? A: A literal pipe inside a cell is escaped as a backslash-pipe so it does not split the column, and a line break inside a cell is written as a
tag, which most Markdown renderers display as a new line. On import the editor reverses both, so tables round-trip safely. Q: What does "pad columns" do? A: When enabled, the editor pads every cell with spaces so the columns line up in the raw source — the pipes form neat vertical lines and the dashes match each column width. This is cosmetic; the rendered table is identical either way. Turn it off for the most compact output. Q: Is my data uploaded anywhere? A: No. Everything runs in your browser. Your table is saved only to this browser local storage so it survives a page reload, and nothing is ever sent to a server. ## Image & PDF Tools > Edit, convert and generate images and PDFs right in your browser. Resize, compress, convert formats, build PDFs, extract colors and more — your files never leave your device, so it's completely private. ### Convert & Compress #### HEIC to JPG / PNG / WebP Converter URL: https://geratools.com/heic-to-jpg Free HEIC to JPG, PNG and WebP converter. Convert iPhone HEIC/HEIF photos instantly in your browser — no upload, no signup, your files never leave your device. How to use: 1. Choose output format: Pick JPG, PNG or WebP and set the quality you want. 2. Add your HEIC files: Drag and drop your .heic or .heif photos, or click to choose them. 3. Download: Each converted image appears with a download button. Nothing is uploaded. FAQ: Q: Are my photos uploaded to a server? A: No. Conversion happens entirely in your browser using the heic2any decoder. Your photos never leave your device — there is no upload step and no account. Q: Why are my iPhone photos in HEIC format? A: Since iOS 11, Apple devices save photos as HEIC (High Efficiency Image Container) to roughly halve the file size at the same quality. Many apps, older Windows PCs, and websites cannot open HEIC, so converting to JPG or PNG makes them universally compatible. Q: Can I convert multiple HEIC files at once? A: Yes. Drop several .heic or .heif files at once and they are all converted in one batch, each with its own download button. Q: Which output format should I pick — JPG, PNG or WebP? A: Use JPG for normal photos you want to share or upload (small, universally supported). Use PNG when you need a lossless copy or transparency. Use WebP for the smallest file at the same quality, ideal for websites. Q: Does converting HEIC to JPG lose quality? A: HEIC and JPG are both lossy, so a small amount of re-compression happens. At the default 90% quality the difference is visually imperceptible. PNG output is lossless but produces a much larger file. Q: Can I convert HEIC on Windows without installing anything? A: Yes. Because everything runs in the browser, this works on Windows, Mac, Linux, Android and iOS with no software install, extension, or Microsoft Store codec needed. Q: Does the converter keep the photo's date and GPS data? A: No. The conversion re-encodes the pixels into a fresh JPG/PNG/WebP, which generally drops the original EXIF metadata including GPS. If you need to inspect or deliberately strip metadata, use the EXIF viewer tool. #### Image Compressor URL: https://geratools.com/image-compressor Free image compressor that reduces JPG, PNG and WebP file size in your browser. Set a target size, see before/after, and download — no upload, fully private. How to use: 1. Set your target: Choose a maximum file size and maximum dimensions. 2. Add images: Drag and drop your images or click to choose them. 3. Download the smaller versions: Each image shows the size saved, with a download button. FAQ: Q: Does compression upload my images? A: No. Compression runs in your browser in a Web Worker. Your images never leave your device — there is no server and no account. Q: Will I lose quality? A: The compressor targets your chosen maximum size while preserving as much quality as possible. For most photos at typical web sizes the difference is invisible; very aggressive targets on detailed images can introduce visible artefacts. Q: Which formats are supported? A: JPG, PNG and WebP. The output keeps the original format, so a JPG stays a JPG and a PNG stays a PNG. Q: How do I compress an image to a specific KB or MB size? A: Set the "Target max size" field to your limit (for example 0.2 for ~200 KB or 1 for ~1 MB). The tool re-encodes and downscales until the result is at or below that size, then shows the actual saving. Q: What does the "max width/height" setting do? A: It caps the longest side of the image in pixels (default 1920). If a photo is larger it is downscaled to fit, which is usually the biggest single saving — a 4000px phone photo rarely needs more than 1920px for web use. Q: Why is my compressed PNG not much smaller? A: PNG is lossless, so it compresses far less than JPG or WebP — especially for photographs. If you need a much smaller file and don't need transparency, convert the PNG to JPG or WebP instead. Q: Is there a file size or batch limit? A: No fixed limit beyond your device's memory. Because everything runs locally, very large images or large batches are bounded only by available RAM in your browser tab. #### Image Resizer (Local) URL: https://geratools.com/image-resizer Free local image resizer. Resize PNG, JPEG, or WebP images to exact pixel dimensions or a percentage with aspect-ratio lock and a quality slider, all on a Canvas in your browser. Nothing is uploaded to any server. How to use: 1. Load an image: Choose any image file; its original dimensions appear so you know your starting point. 2. Set the target size: Enter exact width and height in pixels, or a percentage of the original, and keep aspect ratio locked if you want. 3. Resize and download: Pick JPEG, PNG, or WebP, adjust the quality slider for lossy formats, then resize and download the result. FAQ: Q: Is my image uploaded to a server? A: No. The image is decoded and redrawn on an HTML Canvas entirely in your browser. It never leaves your device, which makes the tool safe for private photos and unreleased assets. Q: Which output format should I choose? A: Use JPEG for photographs to get small files with a quality slider, PNG when you need lossless output or transparency, and WebP for the best compression at a given quality where browser support allows. Q: Will resizing keep the aspect ratio? A: When aspect-ratio lock is on, you set the width and the height is computed automatically so the image is not stretched. Turn the lock off to set both dimensions independently. Q: Why does upscaling look blurry? A: Enlarging an image cannot add detail that was not captured, so the Canvas interpolates between existing pixels and the result softens. For best quality, resize down from a larger original rather than up from a small one. Q: What does the quality slider do? A: For JPEG and WebP it controls the lossy compression level from 0.1 to 1. Lower values shrink the file but introduce artefacts; 0.8 to 0.9 is a good balance. PNG is lossless, so the slider does not apply. #### WebP to JPG Converter URL: https://geratools.com/webp-to-jpg Free WebP to JPG converter. Turn WebP images into widely supported JPEG files instantly in your browser, with an adjustable quality slider and background colour for transparency — no upload, no signup, your files never leave your device. How to use: 1. Set quality and background: Choose the JPG quality and a background colour to fill any transparent areas. 2. Add your WebP files: Drag and drop your .webp images, or click to choose them. 3. Download: Each converted JPG appears with its new file size and a download button. FAQ: Q: Are my images uploaded anywhere? A: No. The conversion runs entirely in your browser using the HTML canvas API. Your images never leave your device. Q: What quality should I choose? A: For photos, 80 to 90 percent keeps the image looking sharp while shrinking the file. Drop below about 70 percent only when you need the smallest possible file and can accept visible artefacts around edges and text. Q: What happens to transparent areas? A: JPG has no transparency channel, so any transparent pixels in the WebP are flattened onto the background colour you pick (white by default) before encoding. Q: Will the JPG match the WebP exactly? A: JPG is lossy, so at lower quality settings you may see slight artefacts around sharp edges and text. Keep quality high for the closest match; JPG is the most universally supported format for photos. Q: Can I convert multiple WebP files at once? A: Yes. Add several .webp files and each is converted independently, showing its new JPG file size and a download button. Q: Why is the JPG sometimes larger than the WebP? A: WebP often compresses more efficiently than JPG at the same visual quality, so converting up to a high-quality JPG can increase the file size. Lower the quality slider if you need a smaller file. Q: When should I pick JPG over PNG? A: Use JPG for photographs and complex images where small file size matters and you do not need transparency. Use PNG when you must keep transparency or want lossless quality for graphics and text. #### Image Resize Tool URL: https://geratools.com/image-resize-tool Free online image resizer. Change an image to exact width and height in pixels, lock the aspect ratio, and export as PNG, JPG or WebP. Runs fully in your browser — nothing is uploaded. How to use: 1. Choose an image: Drop an image onto the box or click to pick a file. Its original size is shown. 2. Set the new size: Enter a width or height in pixels. Keep "aspect ratio" ticked to scale proportionally. 3. Pick a format and download: Choose PNG, JPG or WebP, set the quality if needed, then click Resize and download. FAQ: Q: Does resizing upload my image? A: No. The image is scaled with a canvas in your browser. It is never sent to any server, so it stays completely private. Q: Will resizing reduce quality? A: Making an image smaller is generally crisp because the browser uses high-quality smoothing. Enlarging beyond the original dimensions cannot add detail and will look softer, which is true of any resizer. Q: What formats can I export? A: PNG (lossless), JPG and WebP (with an adjustable quality slider). JPG output is flattened onto a white background because it has no transparency. Q: How do I keep the proportions correct? A: Leave "Keep aspect ratio" ticked. When you change the width the height updates automatically (and vice versa) so the image never looks stretched. Untick it to force exact width and height. Q: Can I enlarge a small image? A: You can set dimensions larger than the original, but upscaling cannot invent detail — the result will look softer. For sharp results, resize down from a larger source rather than up from a small one. Q: What''s the difference between resize and crop? A: Resizing scales the whole image to new dimensions (changing every pixel's size). Cropping cuts away part of the image to change its bounds. Use the image crop tool if you want to trim rather than scale. Q: Why is my resized JPG on a white background? A: JPG has no transparency channel, so when you export to JPG the canvas is filled white first. Choose PNG or WebP if you need to preserve transparency. #### Image to PDF URL: https://geratools.com/image-to-pdf Free image-to-PDF converter. Turn any photo or screenshot into a single-page PDF sized to the image, with adjustable DPI and quality. Built entirely in your browser — nothing is uploaded. How to use: 1. Add an image: Drop an image onto the box or click to choose a file. A preview appears. 2. Choose resolution and quality: Pick a DPI (72 screen, 150 default, 300 print) and a JPEG quality level. 3. Create and download: Click Create PDF, then download the single-page PDF sized to your image. FAQ: Q: Is my image uploaded to make the PDF? A: No. The PDF file is assembled byte-by-byte in your browser from the image you provide. It is never sent to any server. Q: How is the PDF built without a library? A: The image is drawn to a canvas and exported as JPEG bytes, then embedded as a DCTDecode image object inside a minimal, spec-valid PDF (catalog, page, content stream and image XObject). The page is sized to the image at your chosen DPI. Q: Why is the output a JPEG inside the PDF? A: JPEG (DCTDecode) is natively supported by the PDF format, keeps the file small, and works in every PDF reader. Transparent areas are flattened onto white because JPEG has no alpha channel. Q: How does DPI affect the page size? A: The page is sized in points (1/72 inch). At 72 DPI each pixel maps to one point, so the page matches the screen size. At 150 or 300 DPI the same pixels are packed into a smaller physical area, giving a sharper print at a smaller page size. Q: Which DPI should I choose? A: Use 72 for screen-only viewing, 150 for general documents, and 300 for high-quality printing. Higher DPI does not add detail your image lacks, but it sets the correct physical print dimensions. Q: Can I combine several images into one PDF? A: This tool produces a single-page PDF sized to one image. To merge multiple images, convert each and then use a PDF merge tool, or place them in one image first. #### WebP to GIF Converter URL: https://geratools.com/webp-to-gif Free WebP to GIF converter. Turn WebP images into widely compatible GIF files instantly in your browser using a built-in GIF encoder — no upload, no signup, your files never leave your device. How to use: 1. Add your WebP files: Drag and drop your .webp images, or click to choose them. 2. Let the browser convert: Each image is decoded, reduced to a 256-colour palette, and encoded as a GIF in your browser. 3. Download: Every converted GIF appears with a download button. Nothing is uploaded. FAQ: Q: Are my images uploaded to a server? A: No. The browser decodes the WebP and a built-in GIF encoder produces the GIF locally. Your images never leave your device. Q: Why does the GIF look slightly different from the WebP? A: GIF supports only 256 colours, so photos with many shades are reduced to a palette. This is a limitation of the GIF format itself, not the conversion. Q: Can I convert several WebP files at once? A: Yes. Drop multiple .webp files and each is decoded and encoded to GIF independently, with its own download button. Q: Does this convert animated WebP to animated GIF? A: The tool converts a still frame to a single-frame GIF. Animated WebP support depends on what the browser exposes when decoding, so treat it as a still-image converter. Q: What happens to transparency? A: GIF supports only on/off transparency, so semi-transparent pixels are flattened onto a white background during conversion. Q: Why would I use GIF instead of PNG or JPG? A: GIF is accepted by older apps, forums, and chat tools that reject WebP and sometimes PNG. If you need full colour and transparency, PNG is usually the better choice; GIF is best for maximum compatibility. #### Images to PDF Converter URL: https://geratools.com/images-to-pdf Free images-to-PDF converter. Drag in multiple JPG, PNG or WebP files, reorder them, choose A4/Letter/A3 page size, orientation, margins and fit mode, then export one clean PDF. Runs entirely in your browser — nothing is uploaded. How to use: 1. Add your images: Drag a batch of photos or scans onto the drop zone, or click to browse. JPG, PNG, WebP and GIF are all accepted. 2. Put them in order: Drag the thumbnails to reorder, use the up/down arrows, or hit Sort A→Z to order numbered scans automatically. 3. Choose the page layout: Pick a page size (A4, Letter, A3 and more), set orientation, margin width, fit mode and a background colour for any letterboxed space. 4. Export the PDF: Click Download PDF. Each image becomes one page and the whole document is built in your browser, then saved straight to your device. FAQ: Q: Can I combine several images into one PDF? A: Yes — that is exactly what this tool does. Add as many images as you like (up to 60 in one go), arrange them in the order you want, and every image becomes a single page in one merged PDF that downloads as a single file. Q: How do I reorder the images before exporting? A: Drag any thumbnail and drop it where you want it, or use the up/down arrows on each tile. There is also a Sort A→Z button that orders files numerically — handy for scans named page-1, page-2, and so on — plus a Reverse button. Q: What page sizes and orientations are supported? A: You can choose A4, US Letter, US Legal, A3, A5 or Tabloid, in portrait, landscape, or Auto orientation that flips per image to match each photo. There is also a Fit page to each image option that makes every page exactly the size of its image with no whitespace. Q: What is the difference between Contain, Fill and Stretch fit modes? A: Contain scales the image to fit inside the margins without cropping or distortion (letterboxing the rest). Fill scales it to cover the whole page, so edges may be cropped. Stretch forces the image to the exact page box, which can distort the aspect ratio. Contain is the safest default. Q: Are my images uploaded to a server? A: No. Every step — reading the files, decoding them, laying out the pages and generating the PDF — happens locally in your browser using JavaScript. No image or PDF ever leaves your device, which makes it safe for IDs, contracts and private scans. Q: Why is my exported PDF large, and can I shrink it? A: PDF size mirrors the combined size of your source images. To get a smaller file, compress or resize the photos before adding them — run them through an image compressor first — or use a smaller page size and tighter margins so each image is scaled down. #### Image to ASCII Art Converter URL: https://geratools.com/image-to-ascii Free image to ASCII art converter. Upload any picture, tune the width, character set, brightness and contrast, then copy the text or download it as .txt or .png. 100% in your browser — nothing is uploaded. How to use: 1. Upload your image: Drag a photo onto the drop zone or click to pick a PNG, JPG, WebP, GIF or BMP file. 2. Tune the look: Adjust the width slider for detail, pick a character set, and nudge brightness and contrast until the shapes read clearly. 3. Copy or download: Copy the ASCII to your clipboard, or save it as a plain .txt file or a rendered .png image. FAQ: Q: How does an image get turned into ASCII art? A: The tool shrinks your image down to a small grid on a hidden canvas, reads the average brightness of each cell, and replaces it with a character of matching density — dark areas get heavy characters like '@' and bright areas get light ones like '.' or a space. The result is a block of monospace text that re-creates the picture. Q: Is my image uploaded anywhere? A: No. Everything runs in your browser using the HTML canvas API. Your photo is never sent to a server, so even private or sensitive images stay entirely on your device. Q: What image formats can I convert? A: Anything your browser can decode — PNG, JPG/JPEG, WebP, GIF, BMP and usually AVIF. Transparent areas are treated as the background colour so PNG cut-outs convert cleanly. Q: Why does my ASCII art look stretched or squashed? A: Monospace characters are taller than they are wide, so the converter samples about twice as many columns as rows to compensate. If it still looks off, increase the width slider for more rows, or raise contrast so edges stand out. Q: How do I keep the original colours? A: Tick 'Keep original colours' to colour each character with the average colour of the pixels it represents. The coloured version shows in the preview and is preserved when you download the PNG. Q: What is the best width to use? A: For sharing in a chat or code comment, 60–100 characters keeps the art readable. For a detailed poster or PNG export, push the width to 150–300. Wider output captures more detail but needs a smaller font to fit on screen. ### Edit #### Image Metadata Redactor URL: https://geratools.com/image-metadata-redactor Drop a batch of JPEG, PNG, or WebP images and strip all EXIF, IPTC, XMP, and GPS metadata from every one, then download them as a single ZIP. Built for journalists, lawyers, and anyone sharing many images. Nothing is uploaded. How to use: 1. Drop your images: Drag in a folder of JPEG, PNG, or WebP files, or browse to select them. Everything stays in your browser. 2. Scrub the batch: Each image is redrawn on a canvas to discard its metadata, processed one at a time to keep memory low. 3. Download the ZIP: Bundle every cleaned image into a single ZIP archive and save it with one click. FAQ: Q: How is the metadata actually removed? A: Each image is decoded to pixels, drawn onto an HTML canvas, and re-encoded. A canvas export contains only the raw RGBA bitmap, so all EXIF, IPTC, XMP, GPS, and ICC blocks are left behind and cannot be recovered. Q: How many images can I process at once? A: Up to 100 files per batch, each under 60 MB. They are processed sequentially rather than all at once so that even a large batch runs smoothly on modest hardware. Q: Are my images uploaded? A: No. Loading, scrubbing, and zipping all happen locally with the browser File, Canvas, and JSZip libraries. The images never leave your device, which is what makes this safe for sensitive material. Q: Can I keep the original file formats? A: Yes. Choose 'Keep source' to preserve JPEG and WebP and fall back to lossless PNG for other formats, or force a specific output format for the whole batch. Q: Why use this over editing each photo by hand? A: Manually clearing metadata one image at a time is slow and error-prone. Redacting a whole folder in one drop guarantees consistent, complete removal across every file. #### Screenshot Redactor (Blur / Blackbox) URL: https://geratools.com/screenshot-redactor Load a screenshot, drag rectangles over sensitive areas, and apply irreversible pixelation or solid black boxes, then download the sanitised PNG. Redactions are baked into the pixels and processing is fully local — no upload. How to use: 1. Load a screenshot: Choose any PNG, JPEG, or WebP image. It is drawn onto a canvas in your browser with nothing uploaded. 2. Drag over sensitive areas: Pick pixelate or solid-black mode, then drag a rectangle over each region you want to hide. 3. Download the clean PNG: Each redaction is baked permanently into the pixels; download the sanitised, full-resolution image. FAQ: Q: Can the blur be reversed? A: No. Pixelation here averages each block and overwrites the original pixels in the backing canvas, so the underlying detail is genuinely destroyed. This is unlike a CSS blur effect, which only hides pixels visually and can be undone. Q: Is my screenshot uploaded? A: No. The image is loaded, edited, and exported entirely in your browser using the Canvas API. It never leaves your device, which matters when redacting passwords, tokens, or personal data. Q: What is the difference between pixelate and black box? A: A black box paints a solid opaque rectangle, hiding both the content and the fact that there was content. Pixelation keeps the rough shape and colours while making text unreadable — useful when you want context preserved. Q: Does the export keep full resolution? A: Yes. The on-screen view may be scaled down to fit, but redactions are applied to a full-resolution backing canvas, so the downloaded PNG is at the image's native size. Q: Why avoid pixelating small text? A: Very light pixelation of small fonts can sometimes be partially reconstructed. Use a larger block size, or prefer a solid black box, for high-sensitivity items like passwords and account numbers. #### Pixelate Image Online URL: https://geratools.com/image-pixelate Free online image pixelator. Upload an image and apply an adjustable blocky mosaic effect — great for pixel-art looks or censoring sensitive areas — then download the result as a PNG. Runs entirely in your browser; nothing is uploaded. How to use: 1. Upload an image: Choose an image file. It is drawn onto a canvas in your browser. 2. Set the block size: Drag the block-size slider — larger blocks give a chunkier, more abstract mosaic. 3. Download: Click Download PNG to save the pixelated image to your device. FAQ: Q: How does pixelation work here? A: The image is scaled down to a small size and then scaled back up with image smoothing turned off. Each original block of pixels becomes one solid colour, producing the classic mosaic look. A larger block size means fewer, bigger blocks. Q: Is pixelation safe for hiding sensitive information? A: Use a large block size for censoring, but be aware that light pixelation of text or faces can sometimes be partially reversed by determined attackers. For truly sensitive data, draw a solid block over it rather than relying on a mild mosaic. Q: Is my image uploaded anywhere? A: No. The whole effect is computed on a canvas in your browser. The image is never sent to a server. Q: What format is the download? A: The result is exported as a lossless PNG, which keeps the hard block edges crisp. PNG is the right choice for pixel-art style output. #### Image Crop Tool URL: https://geratools.com/image-crop-tool Free online image crop tool. Drag to select a region, fine-tune the pixel coordinates, and download the cropped image. Runs entirely in your browser — your photos are never uploaded. How to use: 1. Add an image: Drop an image onto the box or click to choose a file from your device. 2. Draw the crop area: Drag a rectangle over the image, or type exact X, Y, width and height in pixels. 3. Crop and download: Click Crop to preview the result, then download it as a PNG. FAQ: Q: Are my images uploaded to a server? A: No. The image is decoded into a canvas and cropped locally in your browser. Nothing is ever sent anywhere. Q: How accurate is the crop? A: Cropping is pixel-exact. The displayed selection is scaled for the screen, but the crop is performed on the image's true pixel dimensions, so the output matches the coordinates you set. Q: Which formats can I crop? A: Any image your browser can decode — including JPG, PNG, WebP and GIF (first frame). The cropped output is saved as a lossless PNG. Q: Can I crop to exact pixel dimensions? A: Yes. Besides dragging a rectangle, you can type the exact X and Y offset plus the width and height in pixels, so you can crop to a precise size such as 1080×1080 for a square thumbnail. Q: Does cropping lose quality? A: No re-sampling happens — the chosen rectangle of original pixels is copied out unchanged and saved as a lossless PNG, so the cropped region looks identical to the source. Q: Is there a file size limit? A: There is no fixed limit; the only constraint is your device's memory, since the whole image is decoded into a canvas. Very large photos work but use more RAM. Q: Will the original file be modified? A: No. The crop produces a brand-new PNG for download. Your original file on disk is never touched or overwritten. #### Image Editor URL: https://geratools.com/image-editor Free online image editor. Crop, rotate, flip, tune brightness/contrast/saturation, apply filters and add text overlays, then export as PNG, JPEG or WebP. 100% private — your images never leave your device. How to use: 1. Load an image: Drop a JPG, PNG, WebP or GIF onto the box, or click to choose a file from your device. 2. Transform and adjust: Rotate or flip the image, drag to crop, and use the sliders to set brightness, contrast, saturation, hue and blur, or pick a one-click filter preset. 3. Add text overlays: Add one or more text labels, then choose the font, colour, size, position and an outline so the text stays readable on any background. 4. Export: Choose PNG, JPEG or WebP, set the quality for lossy formats, and download the finished image. FAQ: Q: Are my images uploaded to a server? A: No. The editor decodes your image into a canvas and applies every edit locally in your browser. No image data is ever sent over the network, so even sensitive photos and screenshots stay completely private. Q: Which formats can I open and export? A: You can open any image your browser can decode, including JPG, PNG, WebP and GIF (first frame). You can export the result as a lossless PNG, or as JPEG or WebP with an adjustable quality slider to trade file size against detail. Q: Does cropping or adjusting lose quality? A: Every edit is applied at the image's true pixel resolution, not the scaled on-screen preview, so crops are pixel-exact and adjustments are full-quality. Quality is only reduced if you deliberately choose a lossy JPEG or WebP export at a lower quality setting. Q: What do the brightness, contrast and saturation sliders do? A: They map directly to the canvas filter values. Brightness scales overall lightness, contrast spreads or compresses the tonal range, and saturation controls colour intensity — 100% leaves each channel untouched, below 100% reduces it and above 100% boosts it. Q: Can I add more than one piece of text? A: Yes. You can add any number of independent text overlays, each with its own font, colour, size, position, bold/italic styling and optional dark outline, which is handy for memes, captions, watermarks or labelled diagrams. Q: Are my edits remembered if I reload the page? A: Your adjustment, rotation, filter and text settings are saved in your browser's local storage so they persist across reloads. The image itself is not stored, so you reload your file and your saved look is reapplied instantly. #### Image Border & Frame Maker URL: https://geratools.com/image-border-maker Free image border and frame maker. Add a solid or gradient border, rounded corners and a soft drop shadow to any photo, then download a transparent or matted PNG. Runs entirely in your browser — nothing is uploaded. How to use: 1. Upload your image: Drop a photo onto the box or click to choose a JPG, PNG or WebP file. It stays on your device. 2. Pick a border style: Choose a solid colour or a two-colour gradient, then set the thickness, gradient angle and corner radius. 3. Add a shadow and background: Toggle the drop shadow, tune its blur and opacity, and pick a matte background colour or keep it transparent. 4. Download the PNG: Set an export scale if you want a larger file, then click Download PNG to save the framed image. FAQ: Q: What image formats can I add a border to? A: Any format your browser can decode works as input, including JPG, PNG, WebP, GIF and BMP. The output is always a PNG, so transparency and crisp gradient borders are preserved. Q: Are my photos uploaded to a server? A: No. The image is read locally with the File API, drawn onto an HTML canvas in your browser, and exported as a PNG. Nothing ever leaves your device, which makes it safe for private or sensitive pictures. Q: Can I make the border transparent so it floats on any page? A: Yes. Turn on the transparent background option and the area around the shadow stays fully transparent in the exported PNG, so the framed photo drops cleanly onto a website, slide or document. Q: How are the gradient borders drawn? A: The two colours are blended along a straight line set by the angle slider, using the canvas linear-gradient API. At 0 degrees the gradient runs left to right; at 90 degrees it runs top to bottom; 135 degrees gives the classic diagonal look. Q: Why is the thickness shown as a percentage instead of pixels? A: A percentage of the shorter side keeps the frame visually consistent no matter how big the photo is. A 6 percent border looks the same on a small thumbnail and a large print, whereas a fixed pixel border would look heavy on small images and thin on large ones. Q: Can I export a higher-resolution version for printing? A: Yes. The export scale slider multiplies the canvas resolution up to 3x, so you can produce a sharper PNG for printing or retina displays without re-uploading the original. #### Image Redactor URL: https://geratools.com/image-redactor Free online image redactor. Draw black boxes, white boxes, blur or pixelate regions over faces, addresses, card numbers and other sensitive info, then export a flattened PNG or JPG. 100% in your browser — nothing is uploaded. How to use: 1. Load your image: Drop a PNG, JPG or WebP onto the upload area or pick a file. It is decoded entirely in your browser and never uploaded. 2. Pick a redaction style: Choose a black box, white box, gaussian blur or pixelate mosaic, and set the blur radius or block size if relevant. 3. Draw boxes over sensitive areas: Click and drag across each region you want to hide. Add as many boxes as you need and remove any with the X handle. 4. Export the flattened image: Download a PNG or JPG. Every redaction is baked into the pixels, so the hidden data is genuinely destroyed, not just covered. FAQ: Q: Is the redaction actually permanent, or just an overlay? A: It is permanent. Unlike marking up a PDF or putting a shape over an image in a slideshow, every box here is drawn directly onto the canvas pixels and the exported file is flattened. There is no separate layer hiding the original data, so the redacted pixels cannot be recovered from the saved file. Q: Are my images uploaded to a server? A: No. The file is read with the browser FileReader API, decoded into a canvas, edited and exported entirely on your device. Nothing is sent over the network, which makes the tool safe for IDs, bank statements, medical documents and other private material. Q: What is the difference between black box, blur and pixelate? A: A black or white box replaces the area with a solid colour and destroys all detail — the safest option. Blur applies a heavy gaussian blur, and pixelate replaces the area with a coarse mosaic. Blur and pixelate look softer but, at low strength, can sometimes be partly reversed, so use a high strength or a solid box for anything truly sensitive. Q: Which image formats can I redact? A: Any format your browser can decode, including PNG, JPG, WebP, GIF (first frame) and usually AVIF and BMP. You can export the result as a lossless PNG or a smaller JPG. Q: Does redacting remove EXIF metadata too? A: Yes, as a side effect. Because the image is re-encoded from a canvas, the exported file is stripped of EXIF data such as GPS location and camera details. If you only need to strip metadata without redacting, use the EXIF remover tool instead. Q: Will the exported image keep its original resolution? A: Yes. Redactions are applied in the image's natural pixel coordinates, so the export matches the source resolution exactly even though the on-screen preview may be scaled down to fit your window. Q: Can I redact several areas at once? A: Yes. Draw as many boxes as you like, mix styles, change a box's style after drawing it, undo the last one, or clear everything and start again. All boxes are rendered together when you export. #### CSS Filter Playground URL: https://geratools.com/css-filter-playground Interactive CSS filter playground. Drag sliders for blur, brightness, contrast, saturate, hue-rotate, sepia, grayscale and invert on your own image, compare before/after, save presets, and copy the filter as CSS or Tailwind. 100% in your browser. How to use: 1. Load an image: Upload your own PNG, JPG or WebP, or click "Use sample" to start with the built-in demo image. The file is read locally and never uploaded. 2. Drag the sliders: Adjust blur, brightness, contrast, saturate, hue-rotate, sepia, grayscale, invert and opacity and watch the preview update instantly. Double-click any slider to reset just that filter. 3. Compare and refine: Toggle the before/after split and drag the divider to judge the effect against the untouched original. 4. Save a preset: Name the look and click "Save current" to keep it in your browser for reuse on other images. 5. Copy or export: Copy the filter value, the full CSS rule, or Tailwind classes — or download a PNG with the filter baked into the pixels. FAQ: Q: What does the CSS filter property do? A: The CSS filter property applies graphical effects — blur, colour and tone adjustments — to an element before it is drawn. You chain functions like blur(5px) brightness(110%) contrast(120%) saturate(140%) hue-rotate(30deg), and the browser composites them in order. It works on images, videos, backgrounds and any HTML element, and is GPU-accelerated in modern browsers. Q: Does the filter change my actual image file? A: No. A CSS filter is purely a display effect — the underlying image bytes are untouched, which is why the same source can render differently on different pages. If you want a real filtered file, use the "Download PNG" button: it re-draws the image through an HTML canvas with the same filter applied, producing a new PNG with the effect baked into the pixels. Q: In what order are the filter functions applied? A: Filters are applied left to right, and order matters. brightness(150%) blur(4px) brightens first then blurs the brightened result, while blur(4px) brightness(150%) blurs first. This playground always emits a consistent order so your copied CSS is predictable, but you can reorder the functions by hand afterwards for different looks. Q: How do I convert these values to Tailwind CSS? A: Click "Copy Tailwind" to get arbitrary-value utility classes such as blur-[4px] brightness-[1.1] contrast-[1.2] saturate-[1.4]. Tailwind expresses brightness, contrast and saturate as multipliers (1 = 100%), so the tool divides the percentage by 100 for you. hue-rotate keeps degrees and blur keeps pixels. Q: Which browsers support CSS filters? A: All current versions of Chrome, Edge, Firefox and Safari fully support the standard filter functions used here. Support has been stable for years, so no vendor prefix is needed for production. The drop-shadow and url() SVG filters have a few edge-case differences, but blur, brightness, contrast, saturate, hue-rotate, sepia, grayscale, invert and opacity are universally safe. Q: Is my image private? A: Completely. The image is read with the browser FileReader API, rendered as a local data URL, and every slider, preview, preset and PNG export happens on your device. Nothing is uploaded, and your saved presets live only in this browser via localStorage. #### Image Crop & Straighten URL: https://geratools.com/image-crop-straighten Free online image crop and straighten tool. Drag a crop box, level a crooked horizon by fractions of a degree, lock an aspect ratio, flip, then export as PNG, JPG or WebP. 100% in your browser — nothing is uploaded. How to use: 1. Load your image: Click choose an image and pick any photo. It is decoded in your browser and never uploaded. 2. Straighten the angle: Drag the angle slider (or tap the plus and minus 0.1 degree buttons) until the horizon or edges are level. 3. Set the crop box: Drag the box to reposition it and drag the corner handles to resize. Pick an aspect ratio to lock the proportions. 4. Export: Choose PNG, JPG or WebP, set quality, then click crop and export and download the result. FAQ: Q: What does straightening actually do to my photo? A: It rotates the whole image about its centre by the exact angle you choose — down to a tenth of a degree — so a tilted horizon or a crooked document edge becomes level. The crop box then trims away the empty triangular corners that rotation creates, leaving a clean rectangular photo with no transparent or black wedges. Q: How precise is the angle control? A: The slider moves in 0.1 degree steps across a plus or minus 45 degree range, and the plus and minus buttons nudge by exactly 0.1 degree at a time. That is fine enough to level a sea horizon or a building edge that the eye reads as crooked. Dedicated 90 degree rotate buttons handle quarter turns for portrait and landscape swaps. Q: Does cropping reduce my image quality? A: No. Cropping copies the original pixels inside your selection at full resolution — there is no resampling for a straight crop. Straightening does resample once (any rotation must), and the tool renders at full resolution with high-quality smoothing so the loss is minimal. Export as PNG to keep it lossless. Q: Can I lock a specific aspect ratio like 16:9 or 1:1? A: Yes. Choose from Free, 1:1, 4:3, 3:2, 16:9, 3:4 or 2:3. When a ratio is locked the crop box keeps those proportions as you resize, which is ideal for social avatars, thumbnails, banners and print sizes. Pick Free to crop to any dimensions you like. Q: Why is the background a checkerboard pattern? A: The checkerboard marks transparency. After a fine rotation the corners outside the original photo are transparent. Keep your crop box inside the image to avoid them, or export as JPG which fills those areas with white instead of leaving them see-through. Q: Is my photo uploaded to a server? A: Never. The whole tool runs in your browser using the canvas API. Your image is decoded locally, rotated and cropped on your own device, and the download is generated in memory. No file ever leaves your computer, which makes it safe for private documents and personal photos. ### PDF Tools #### Split PDF & Extract Pages URL: https://geratools.com/split-pdf Free PDF splitter and page extractor. Open a PDF, preview every page, pick ranges like 1-3, 5, 8-10 or click thumbnails, then export as one PDF or split into single pages. 100% in your browser — nothing is uploaded. How to use: 1. Open your PDF: Drag a PDF onto the drop zone or click to choose a file. Every page is rendered as a thumbnail preview in your browser. 2. Choose the pages: Type a range such as 1-3, 5, 8-10, click thumbnails to pick pages, or choose Split all to separate every page. 3. Export: Export the chosen pages as a single new PDF, or split each selected page into its own one-page PDF. Each file downloads straight to your device. FAQ: Q: How do I extract specific pages from a PDF? A: Open the PDF, switch to the Page ranges tab and type the pages you want — for example 1-3, 5, 8-10. The tool shows a live count of how many pages are selected, then exports just those pages into a brand-new PDF. Q: Can I delete pages from a PDF instead of extracting them? A: Yes — extracting and deleting are two sides of the same coin. To remove pages 4 and 7 from a 10-page file, simply extract the pages you want to keep (1-3, 5-6, 8-10). The result is your original document minus the unwanted pages. Q: How do I split one PDF into separate single-page files? A: Use the Split all tab. The tool creates one one-page PDF for every page in the document and downloads each file in turn, named with a zero-padded page number so they stay in order. Q: Are my files uploaded to a server? A: No. Both the page previews and the new PDFs are generated entirely in your browser using pdf.js and pdf-lib. Your document never leaves your device, which makes this safe for contracts, bank statements, medical records and other sensitive files. Q: Does it work with password-protected or encrypted PDFs? A: The tool can open and split many encrypted PDFs that do not require a password to view. If a file is locked with an open password, your browser cannot decrypt it and the preview will fail — remove the password in your PDF viewer first, then split. Q: Will extracting pages reduce the file size? A: Usually, yes. Because only the pages you select are copied into the new document, fonts and images tied to discarded pages are dropped, so a few pages pulled from a large report are often dramatically smaller than the original. Q: Is there a page limit or watermark? A: There is no page limit, no sign-up and no watermark. The only practical limit is your device's memory, since the whole PDF is processed locally — very large scanned files (hundreds of pages) may render previews slowly. #### Extract Images from PDF URL: https://geratools.com/pdf-extract-images Free tool to extract embedded images from a PDF. Pulls out every photo, logo and figure, previews them as PNGs and downloads all of them in one ZIP. Runs entirely in your browser — your file is never uploaded. How to use: 1. Open your PDF: Drag a PDF onto the drop zone or pick it with the file chooser. The file stays on your device and is never uploaded. 2. Tune what gets kept: Set a minimum size to skip tiny icons, and leave de-duplication on to drop the logo that repeats on every page. 3. Preview and download: Review the thumbnail grid, download any single image as a PNG, or grab everything at once with Download all as ZIP. FAQ: Q: What is the difference between extracting images and converting a PDF to images? A: Extracting pulls out the original embedded raster images (the actual photos and logos stored inside the file) at their native resolution. Converting a PDF to images rasterises each whole page — text, vectors and all — into one picture per page. Use this extractor when you want the source photos back; use a PDF-to-images tool when you want a snapshot of each page. Q: Why does the tool say no images were found? A: Some PDFs contain only text and vector graphics with no embedded bitmaps — there is simply nothing raster to pull out. Charts, line art and typeset text are drawn as vectors, not stored as images, so they cannot be extracted. In that case, rasterise the pages with a PDF-to-images tool instead. Q: Are my files uploaded anywhere? A: No. The PDF is parsed entirely inside your browser using a local WebAssembly engine. Nothing is sent to a server, so confidential documents, scans and contracts never leave your computer. Q: In what format are the extracted images saved? A: Every image is re-encoded to lossless PNG, which preserves transparency where the original had it. PNG is a safe universal format that opens everywhere, and re-encoding avoids exposing the odd internal codecs some PDFs use. Q: What does the de-duplication option do? A: It computes a small perceptual fingerprint of each image and skips ones that look identical to images already kept. This removes the header logo, watermark or letterhead that repeats on every page, so you are left with the unique pictures rather than dozens of copies of the same graphic. Q: Is there a limit on file size or number of pages? A: The tool accepts PDFs up to 250 MB and has no page limit, but very large files take longer because every page is scanned in your browser. A progress bar shows which page is being processed so you can tell it is still working. ### Makers & Generators #### Avatar Identicon Generator URL: https://geratools.com/avatar-identicon-generator Generate deterministic SVG identicon avatars from any seed string using a hash-driven symmetric pattern algorithm. The same input always yields the same avatar, perfect for default user avatars in apps without profile photos. How to use: 1. Enter a seed: Type any string such as an email, username, or user ID. The same seed always produces the same avatar, so each user gets a stable identity. 2. Adjust size and background: Set the pixel size and pick a background color. The pattern color is derived automatically from the seed for a consistent look. 3. Export the avatar: Download the avatar as an SVG file or copy the SVG markup to embed it inline in your app or website. FAQ: Q: What is an identicon? A: An identicon is a small image generated automatically from a piece of data, usually a hash of a username or email. It gives every user a unique, recognizable default avatar without needing them to upload a photo. Q: Why is the same seed always the same avatar? A: The seed is run through a deterministic hash function, so identical input always produces identical output. This means a user's avatar stays stable across sessions and devices without storing an image. Q: What hash does the tool use? A: It uses FNV-1a, a fast non-cryptographic 32-bit hash. The hash value selects the avatar's hue, and further mixing fills a symmetric grid of squares, giving a distinct but reproducible pattern per seed. Q: Why is the pattern symmetric? A: The grid is mirrored left to right, so only the left three columns are independent and the right two are reflections. Symmetry makes the shapes read as a coherent emblem rather than random noise, the same approach popular identicon styles use. Q: Is the seed sent anywhere? A: No. Hashing and rendering happen entirely in your browser, so the seed string and the resulting avatar never leave your device. #### Barcode Generator (EAN-13) URL: https://geratools.com/barcode-generator-ean13 Free EAN-13 barcode generator. Enter a 12-digit product number and get a scannable barcode as scalable SVG, with the modulo-10 check digit calculated and verified for you. Runs entirely in your browser. How to use: 1. Enter the product number: Type the first 12 digits of your EAN-13 number; the 13th check digit is calculated automatically. You can also paste a full 13-digit code to verify it. 2. Read the barcode: A scannable EAN-13 barcode appears instantly, with the human-readable digits printed underneath in the standard 1-6-6 layout. 3. Download or copy: Download the barcode as an SVG to print on product labels, or copy the SVG markup to embed it directly in a document. FAQ: Q: How is the EAN-13 check digit calculated? A: Multiply the digits in odd positions (1st, 3rd, 5th...) by 1 and the digits in even positions by 3, sum the products, then the check digit is the amount needed to round that sum up to the next multiple of 10. This tool computes it for you. Q: What is the difference between EAN-13 and UPC-A? A: UPC-A is a 12-digit code used mainly in North America; EAN-13 is its 13-digit international superset. A UPC-A number is simply an EAN-13 with a leading zero, so the same bars can represent both. Q: Why does the first digit not appear as bars? A: In EAN-13 the leading digit is encoded indirectly through the parity pattern (L or G) of the six left-hand digits, rather than as its own set of bars. The scanner reconstructs it from that parity, which is why it sits in the left quiet zone. Q: Is the SVG suitable for printing real product labels? A: Yes. The output is true vector with correct module widths and quiet zones, so it scans reliably when printed at 100% or larger. Always test-scan a printed sample before a full production run. Q: Do I need to register the number with GS1? A: This tool generates a technically valid barcode for any number you supply, which is great for testing and mockups. To sell a product through retailers you must obtain a genuine GTIN from GS1 so the number is globally unique. #### Organic Blob SVG Generator URL: https://geratools.com/blob-svg-generator Generate random organic blob shapes as smooth SVG paths with adjustable complexity, irregularity, seed, and colour. Reproducible blobs for hero backgrounds, decorative shapes, and modern landing-page accents. How to use: 1. Set complexity and irregularity: Increase points for a more lobed blob, and raise irregularity to make the radius vary more wildly between points. 2. Lock or randomize the seed: Keep a seed to reproduce the same blob, or hit randomize to roll a fresh shape until you like it. 3. Copy the SVG: Pick a fill colour and copy the SVG markup to drop into your page as a decorative background shape. FAQ: Q: How is an organic blob shape generated? A: Points are placed evenly around a circle, then each point's radius is randomly pulled inward by a fraction set by the irregularity control. Connecting those points with smooth cubic Bezier curves produces a closed, organic loop rather than a jagged polygon. Q: Why does the same seed always give the same blob? A: The randomness comes from a seeded mulberry32 pseudo-random generator. Feeding it the same seed reproduces the exact same sequence of radius offsets, so the blob is fully deterministic and you can recreate or share a specific shape. Q: What do points and irregularity each control? A: Points set how many lobes the blob can have: more points give a more complex, bumpy outline. Irregularity sets how far each radius can shrink from the base, so higher values create deeper dents and a less circular shape. Q: How do I keep the curve smooth and continuous? A: The path uses a Catmull-Rom style smoothing where each Bezier control point is derived from its neighbouring points' positions. This keeps the tangents continuous around the whole loop, so there are no visible kinks where segments meet. Q: What are blobs good for in a design? A: Blobs are popular as soft background accents behind hero sections, decorative shapes around illustrations, or coloured masks for images. Their organic, irregular outline contrasts with rigid grid layouts and gives a page a friendlier, modern feel. #### Dark Mode Color Palette Generator URL: https://geratools.com/color-palette-generator-dark Produces dark-theme color palettes — a near-black background, layered surfaces, a vivid accent, and a light text color — with WCAG contrast checked against the background. Copy hex codes for building readable dark-mode UIs. How to use: 1. Generate the theme: Click Generate to build a dark palette of background, two surface layers, an accent, and a text color. 2. Check the contrast: Read the WCAG contrast ratio of the text color against the background to confirm it is readable. 3. Copy the roles: Click any swatch to copy its hex code, each labeled by its UI role. FAQ: Q: What roles does the palette assign? A: It produces five purpose-built colors: a near-black background, two slightly lighter surface layers for cards and raised elements, a vivid accent for buttons and links, and a near-white text color. Each is labeled so you know where it goes. Q: How is the contrast ratio calculated? A: The tool computes WCAG relative luminance for the text and background colors and divides the lighter plus 0.05 by the darker plus 0.05. A result of 4.5 or higher passes WCAG AA for normal text, and 7 or higher passes AAA. Q: Why use layered surfaces instead of one dark color? A: In dark UIs, elevation is shown by making raised surfaces slightly lighter rather than by shadows alone. Two surface layers let you separate the page background, cards, and modals so the interface reads with depth. Q: Why not use pure black? A: Pure black with pure white text creates harsh contrast that can cause eye strain and halation. A very dark gray background with an off-white text color is gentler while still passing accessibility checks. Q: What format are the colors? A: Each color is shown as a hex code such as #121417, ready to drop into CSS variables or a design tool. Values are computed in HSL and converted to hex. #### Earth Tone Palette Generator URL: https://geratools.com/color-palette-generator-earth Creates warm earth-tone palettes — browns, tans, olive greens, terracotta, and clay — using restrained HSL hues and moderate saturation. Copy natural hex codes for eco brands, artisan products, and nature-inspired designs. How to use: 1. Generate the palette: Click Generate to build five earth-tone swatches drawn from natural hue bands. 2. Inspect the tones: Review the spread from light tan through clay and terracotta to deep brown and olive. 3. Copy the hex codes: Click any swatch to copy its hex code for your design tool or CSS. FAQ: Q: What counts as an earth tone? A: Earth tones are colors found in soil, stone, clay, and foliage: browns, tans, ochres, terracottas, and muted greens. In HSL they live mostly in the warm orange-to-yellow hues, roughly 20 to 50 degrees, plus muted greens near 60 to 110 degrees, all at moderate saturation. Q: How are the colors chosen? A: Each swatch picks a hue from the warm earth band, then sets a moderate saturation and a lightness chosen to span the palette from a light sand to a deep soil brown. One olive-green hue is included for natural balance. Q: Why keep saturation moderate? A: Natural materials are rarely fully saturated; pushing saturation too high makes browns look orange and greens look artificial. Holding saturation in the 25 to 55 percent range keeps the palette grounded and organic. Q: Are earth tones good for text? A: The darker browns and olives in the palette work well for text on a light tan background. Always check that the text-to-background contrast meets at least 4.5 to 1 for body copy. Q: What format are the colors? A: Each swatch shows a hex code such as #A8744F, computed in HSL and converted to hex, ready to paste into CSS or a design tool. #### CSS Animation Generator URL: https://geratools.com/css-animation-generator Generates CSS @keyframes animation code for common effects: fade, slide, bounce, spin, pulse, and shake. Tune duration, delay, timing, and iteration, preview live, then copy ready-to-use CSS. No JavaScript required. How to use: 1. Pick an effect and settings: Choose an effect like fade or bounce, then set the duration, delay, timing function, and iteration count. 2. Preview the animation: Watch the live preview and click Replay to run it again with your current settings. 3. Copy the CSS: Click Copy CSS and paste the keyframes and class into your stylesheet, then add class gera-animated to any element. FAQ: Q: What are CSS keyframes? A: Keyframes define the steps of an animation using the @keyframes at-rule, listing how properties change at points from 0 to 100 percent. The animation property then attaches those keyframes to an element along with timing, delay, and iteration settings. Q: Which effects can I generate? A: Fade, slide, bounce, spin, pulse, and shake. Slide supports a direction, while bounce and shake expose a distance or amplitude so you can control how far the element moves. Q: Does this need any JavaScript? A: No. The generated code is pure CSS — an @keyframes block plus a class. The live preview on this page uses a remount to replay the animation, but the exported CSS runs on its own with no scripting. Q: How do I apply the animation to my element? A: Paste the generated CSS into your stylesheet and add the class gera-animated to the element you want to animate. The animation runs automatically when the element renders because animation-fill-mode is set to both. Q: Can I loop the animation forever? A: Yes. Set the iteration count to infinite and the animation repeats continuously. This works well for pulse and spin loaders; for entrance effects like fade and slide, keep the count at 1. Q: Why does my element jump when the animation starts? A: The generated keyframes set the entire transform property, so any transform already on the element (like translateX(-50%) centering) is overwritten for the animation's duration. Merge your existing transform into the keyframe values, or animate a wrapper element instead. Q: How do I stagger the animation across a list of items? A: Give each item an index custom property (style="--i: 2") and set animation-delay: calc(var(--i) * 80ms) in the stylesheet. Every item shares the same keyframes; only the delay differs. Steps of 80–120ms read as a smooth cascade. #### Geometric Pattern SVG Generator URL: https://geratools.com/geometric-pattern-svg-generator Generate repeating geometric SVG patterns from triangles, hexagons, squares, and diamonds with custom size and colour. Copy a tiling CSS background-image data URI or the raw SVG tile for crisp, lightweight backgrounds. How to use: 1. Pick a shape: Choose squares, triangles, hexagons, or diamonds as the motif for the repeating tile. 2. Set size and colours: Adjust the tile size and pick a shape colour and background colour, then toggle filled or outline mode. 3. Copy the pattern: Copy the CSS background that tiles the data URI, or grab the raw SVG tile to embed directly. FAQ: Q: How does an SVG pattern tile seamlessly? A: The generator draws a single motif inside a square tile, then sets the tile as a CSS background-image with a matching background-size. The browser repeats that one tile across the element, so the motif lines up edge to edge automatically. Q: Why use SVG instead of a PNG tile? A: SVG patterns are vector, so they stay razor sharp on high-DPI screens and at any zoom level. A small SVG tile is also far lighter than an equivalent raster image and lets you recolour the shapes by editing a single attribute. Q: What is the difference between filled and outline mode? A: Filled mode paints the shape solid in your chosen colour, giving a bold pattern. Outline mode draws only a stroked border with a transparent interior, producing a lighter, more subtle grid that works well behind text. Q: How are the hexagons calculated? A: Each hexagon is built from six points placed at 60-degree intervals around the tile centre using cosine and sine, with the first point rotated to give a pointy-top orientation. The radius is set just inside the tile so the shape never clips its edges. Q: Can I change the spacing between shapes? A: Yes, indirectly. A larger tile size leaves more empty background around each motif, increasing the apparent spacing, while a smaller tile packs the shapes tighter. Adjust the size slider until the density looks right for your layout. #### Isometric Grid SVG Generator URL: https://geratools.com/isometric-grid-svg-generator Generate tileable isometric grid backgrounds as SVG for technical illustration and architecture diagrams. Choose line or dot mode and adjust cell size, projection angle, weight, and colour, then copy CSS or raw SVG. How to use: 1. Choose lines or dots: Select line mode for a full isometric lattice, or dot mode for a lighter point grid to draw over. 2. Set angle and cell size: Use 30 degrees for a classic 2:1 isometric look, then size the cell to control grid density. 3. Copy the background: Copy the tiling CSS background or the raw SVG tile and drop it behind your diagram canvas. FAQ: Q: What angle makes a true isometric grid? A: A 30-degree angle from the horizontal gives the classic 2:1 isometric projection used in pixel art and technical drawing, where two horizontal pixels correspond to one vertical pixel of rise. The angle slider lets you deviate for dimetric or near-isometric looks. Q: How is the grid made tileable? A: The generator computes the vertical rise across one cell as cell width times the tangent of the angle, then builds a tile two rises tall so the up-sloping and down-sloping diagonals meet exactly at the tile edges. Repeating that tile produces a seamless lattice. Q: When should I use dot mode instead of lines? A: Dot mode places a marker only at each lattice point, giving a quiet reference grid that does not compete with your drawing. It is ideal as a backdrop for sketching isometric icons or diagrams where solid lines would clutter the view. Q: Why does the tile height change when I move the angle? A: The tile height equals two times the rise, and the rise depends on the tangent of the angle. A steeper angle increases the rise, so the tile gets taller; the copied CSS background-size updates automatically to keep the grid seamless. Q: Is the output suitable for high-resolution screens? A: Yes. The grid is pure vector SVG, so it renders crisply at any zoom level or pixel density without the blurring you would get from a raster grid image. It also stays a few hundred bytes regardless of how large the background is. #### QR Code Generator (Wi-Fi) URL: https://geratools.com/qr-code-generator-wifi Free Wi-Fi QR code generator. Enter your SSID, password and security type to produce a scannable QR code that lets phones join the network automatically. Runs entirely in your browser — your password is never uploaded. How to use: 1. Enter your network details: Type the network name (SSID), choose the security type, and enter the password if the network is secured. 2. Scan or download: A QR code is generated instantly. Point a phone camera at it to join, or download the SVG to print on a sign. 3. Place it where guests can see it: Print the QR and put it on a table tent, menu, or wall so visitors can connect without typing the password. FAQ: Q: How does a Wi-Fi QR code work? A: It encodes a special text string in the form WIFI:T:WPA;S:SSID;P:password;; that Android and iOS cameras recognise. When scanned, the phone offers to join that exact network with the embedded credentials, so nobody has to type the password. Q: Is my Wi-Fi password sent anywhere? A: No. The QR code is built entirely in your browser using a self-contained encoder. Your SSID and password never leave your device and are not transmitted to any server. Q: Which security type should I choose? A: Choose WPA for almost all modern networks (it covers WPA, WPA2 and WPA3). Use WEP only for very old routers, and Open for networks with no password at all. Q: Why is my SSID or password not scanning correctly? A: Special characters such as a semicolon, comma, colon, backslash or double-quote must be escaped in the Wi-Fi string. This tool escapes them automatically, so the encoded payload matches your real credentials exactly. Q: What is a hidden network and should I tick the box? A: A hidden network does not broadcast its SSID, so phones cannot find it by browsing. If your router hides the SSID, tick the box so the QR tells the phone to connect anyway; otherwise leave it unticked. #### Full Color System Generator URL: https://geratools.com/random-color-system-generator Free color system generator. Builds a full palette from one seed hue — primary, secondary, accent, a neutral ramp and semantic success, warning, error and info tokens. Exports CSS custom properties and JSON. Runs entirely in your browser. How to use: 1. Choose a seed hue: Set the base hue with the slider or pick Random. Everything else is derived from this single hue for a cohesive system. 2. Pick a harmony: Choose complementary, analogous or triadic to decide how the secondary and accent hues relate to the primary. 3. Export CSS or JSON: Copy the generated CSS custom properties or the JSON token object straight into your stylesheet or design-token pipeline. FAQ: Q: How is the palette derived from one hue? A: The seed hue sets the primary color in HSL. Secondary and accent hues are rotated from it by the chosen harmony angle (180 degrees for complementary, plus or minus 30 for analogous, plus or minus 120 for triadic). The neutral ramp shares the primary hue at very low saturation, and semantic colors use fixed conventional hues. Q: Why are semantic colors fixed rather than random? A: Success, warning, error and info colors carry meaning users learn across the web — green, amber, red and blue. Randomising them would break that expectation, so the generator anchors them to conventional hues and only nudges lightness to fit your system. Q: What is the neutral ramp for? A: Neutrals are the greys used for text, borders, surfaces and backgrounds. The ramp gives you several steps from near-white to near-black, tinted slightly toward the primary hue so the greys feel part of the brand rather than flat. Q: What formats can I export? A: Two: CSS custom properties (a block of --color-* variables you paste into :root) and a JSON object keyed by token name. Both list the same hex values, so you can wire them into a stylesheet or a design-token build step. Q: Does anything leave my browser? A: No. The whole system is computed locally with HSL math and rendered as hex. There are no network calls, so it works offline and nothing you generate is uploaded. #### SVG Pattern Generator URL: https://geratools.com/svg-pattern-generator Generate seamless, repeating SVG patterns including stripes, dots, chevrons, crosshatch, and grids with configurable colors, scale, and line weight. Export a tile or copy a ready-to-use CSS background. Ideal for web and print textures. How to use: 1. Choose a pattern: Select a pattern type such as dots, diagonal stripes, chevron, crosshatch, or grid. Each is drawn to tile seamlessly when repeated. 2. Tune colors and scale: Set the foreground and background colors, the tile size in pixels, and the line or dot weight to control density and contrast. 3. Export or copy: Download the single tile as an SVG, or copy a ready-made CSS background declaration that repeats the tile across any element. FAQ: Q: What makes the patterns seamless? A: Every shape is positioned so its edges align across tile boundaries. When the tile repeats, the lines and dots continue without visible seams, producing an infinite texture from one small SVG. Q: How do I use the pattern in CSS? A: Copy the CSS background declaration and apply it to any element. It sets a data-URI background-image with background-repeat, so the tile fills the element regardless of its size. Q: Why use SVG instead of a PNG texture? A: SVG patterns are resolution-independent, stay razor-sharp on high-DPI screens, and are usually only a few hundred bytes. You can also recolor them instantly without re-exporting an image. Q: Can I use these patterns in print? A: Yes. Download the tile SVG and place it in design software, or scale it up freely. Because SVG is vector-based it prints crisply at any size and DPI. Q: Does increasing the tile size change the pattern? A: Tile size sets how large one repeat unit is, which controls how dense the pattern appears. A smaller tile packs more repeats into the same area; a larger tile spreads the motif out. #### Wave SVG Generator URL: https://geratools.com/wave-svg-generator Generate smooth SVG wave dividers for web page section separators with adjustable amplitude, frequency, phase, height, and colour. Copies full-width responsive inline SVG you can drop between sections. How to use: 1. Shape the wave: Adjust amplitude for wave height, frequency for how many crests span the width, and phase to shift the crests sideways. 2. Set height and colour: Choose the divider height and fill colour, and flip it vertically if you want the wave to point upward. 3. Copy the SVG: Copy the inline SVG markup and place it directly between two sections; it stretches to full width automatically. FAQ: Q: How does the wave stay smooth instead of jagged? A: The path samples a sine curve at evenly spaced points, then connects them with cubic Bezier segments whose control points sit halfway between samples. This rounds the corners that straight line segments would leave, giving a continuous, fluid wave. Q: Why does the SVG scale to any screen width? A: The SVG uses a fixed viewBox of 1440 units wide with preserveAspectRatio set to none. That tells the browser to stretch the path horizontally to fill its container while keeping the chosen pixel height, so one wave works across all breakpoints. Q: What do amplitude and frequency control? A: Amplitude is the vertical distance from the wave's midline to its crest, so larger values make taller waves. Frequency is how many full wave cycles fit across the width, so higher values pack in more, shorter crests. Q: How do I place the wave between two sections? A: Drop the inline SVG at the bottom of the upper section or the top of the lower one, and set the wave fill colour to match the adjacent section's background. The filled area below the curve blends into that section, creating the divider effect. Q: Should I use inline SVG or a background image? A: Inline SVG is best for dividers because it stretches responsively and lets you recolour the fill with CSS. A background image works too but is harder to make full-width without distortion. This tool outputs inline SVG ready to paste. #### Code 128 Barcode Generator URL: https://geratools.com/barcode-generator-code128 Free Code 128 barcode generator. Turn any text or number into a scannable, spec-correct Code 128 barcode with an automatic mod-103 check digit, then download it as a PNG. Everything is generated locally in your browser. How to use: 1. Enter your text: Type the text or number you want to encode. Printable ASCII characters are supported. 2. Adjust the size: Set the module width and bar height, and choose whether to print the human-readable text under the bars. 3. Copy or download the barcode: Click the barcode (or the Copy PNG button) to copy it to your clipboard, download it as a PNG or SVG, or have it emailed to you for later. FAQ: Q: What encoding does this use? A: It produces a spec-correct Code 128 barcode following ISO/IEC 15417. It auto-selects Code Set C for runs of four or more even-length digits (two digits per symbol) and Code Set B otherwise, then appends a weighted modulo-103 check digit and the stop pattern. Q: How is the Code 128 check digit calculated? A: It is a weighted modulo-103 sum: the start value plus each data symbol value multiplied by its position, all taken mod 103. This check symbol is encoded just before the stop pattern so scanners can detect read errors. Q: Will the barcode actually scan correctly? A: Yes. The bar and space widths come directly from the standard Code 128 pattern table and include the mandatory check digit and quiet zones, so any compliant scanner can read it. For best results print at a module width of 2px or more and keep the white margins. Q: What is the difference between Code Set B and Code Set C? A: Code Set B encodes the full printable ASCII range one character per symbol; Code Set C packs two digits into a single symbol, which makes long numbers much shorter. This generator switches to Code C automatically when it saves space. Q: How many characters can a Code 128 barcode hold? A: There is no fixed limit, but practical scanning gets harder as the barcode gets wider. For numeric data, Code Set C roughly halves the width compared with encoding each digit individually. Q: Can I use this for shipping labels or asset tags? A: Yes. Code 128 is the standard for shipping labels, retail packaging, asset tags and internal documents because it is compact and encodes the full ASCII set. Download the PNG and print it at a sufficient size. Q: Is my text uploaded anywhere? A: No. The barcode is drawn entirely in your browser using a canvas. Your text and the generated image never leave your device. #### Random Color Generator URL: https://geratools.com/random-color-generator Free random color generator that creates six random colors at once with HEX, RGB, and HSL values. Click any swatch to copy its HEX. Runs entirely in your browser — nothing is uploaded. How to use: 1. View the swatches: Six random colors appear as soon as the page loads. 2. Generate new colors: Click Generate new colours for a fresh set of six. 3. Copy a value: Click any swatch to copy its HEX code to your clipboard. FAQ: Q: What color formats are shown? A: Each swatch shows HEX, RGB, and HSL values so you can use the color in CSS, design tools, or code. Q: How are the colors chosen? A: Each red, green, and blue channel is drawn independently with a cryptographically secure random generator for a fully random color. Q: How many colors are generated at once? A: Six fresh random colors appear together. Click "Generate new colours" for another set of six whenever you want more options. Q: How do I copy a color? A: Click any swatch and its HEX code is copied to your clipboard, ready to paste into CSS, a design tool, or code. Q: Are the colors evenly distributed? A: Yes. Each of the red, green and blue channels is picked independently and uniformly across 0–255 using rejection sampling, so no color or brightness range is favoured over another. Q: Why does each swatch show readable text in a different color? A: The tool computes the perceived luminance of each color (0.299·R + 0.587·G + 0.114·B) and switches the label between dark and light text so it stays legible on both bright and dark swatches. Q: Is anything sent to a server? A: No. Colors are generated in your browser and are never uploaded or stored. #### QR Code Generator with Logo URL: https://geratools.com/qr-code-with-logo Free QR code generator with a centre logo. Add your brand logo, pick custom colours, choose URL/Wi-Fi/vCard/email/SMS content, and download a crisp PNG or SVG. 100% in your browser — nothing is uploaded. How to use: 1. Choose what the code should do: Pick a content type — URL, plain text, email, phone, SMS, Wi-Fi login or a contact card (vCard) — and fill in the fields. 2. Add your logo: Upload a PNG, JPG, WebP or SVG logo. It is placed in the centre on a clean backing plate so the code still scans. 3. Style the code: Set foreground and background colours (or a transparent background), the output size, the quiet-zone margin and the logo size. 4. Keep it scannable: Leave error correction on H (High) whenever you embed a logo, so the lost area is recovered automatically. 5. Download: Export a PNG at 1x or 2x resolution, or an SVG for infinitely scalable print artwork. FAQ: Q: Why does adding a logo not break the QR code? A: QR codes carry Reed-Solomon error-correction data. At the High (H) level about 30% of the modules can be damaged or covered and the code still reads. The tool draws a clean backing plate behind your logo so the covered area stays well within that recoverable budget. Q: What size should my logo be? A: Keep the logo to roughly 18-24% of the code width. The size slider is capped at 32% on purpose — bigger than that and even High error correction starts to fail. Always test the finished code with your phone before printing. Q: Can I make the background transparent? A: Yes. Tick the transparent-background option and the exported PNG has no fill behind the dark modules, so it sits cleanly on coloured packaging or a website hero. The logo still gets a small white backing plate for contrast. Q: Which content types are supported? A: URL, plain text, an email (with optional subject), a phone number, a pre-filled SMS, Wi-Fi network login (SSID, password, security type, hidden flag) and a full contact card in vCard format that adds straight to a phone address book. Q: Should I download PNG or SVG? A: Use PNG for anything with a logo — the logo overlay is rendered on a canvas, so it only exists in the PNG. Use SVG when you need a razor-sharp, infinitely scalable code for large-format print and you do not need the logo embedded. Q: Is my data private? A: Completely. The QR code, the logo and every export are generated in your browser with no network calls. Your URLs, Wi-Fi passwords and contact details never leave your device. #### Business Card Designer URL: https://geratools.com/business-card-designer Free online business card maker. Pick a template, add your contact details and logo, design the front and back, then export print-ready PNG and PDF files. Everything runs in your browser — nothing is uploaded. How to use: 1. Pick a template: Choose one of the six starter templates as a base for the colours, font and layout. 2. Fill in your contact details: Add your name, job title, company, phone, email, website and address. The front and back update live as you type. 3. Brand it: Upload your logo, then fine-tune the background, panel, text, accent and muted colours with the colour pickers. 4. Export: Download the front or back as a 1050x600 PNG, both sides at once, or a two-page print-ready PDF at the real 3.5x2 inch card size. FAQ: Q: What size are the exported business cards? A: The standard US/UK business card size of 3.5 x 2 inches. PNGs export at 1050 x 600 pixels, which is exactly 300 DPI, the resolution most print shops ask for. The PDF is laid out at the physical 3.5 x 2 inch size with the front on page one and the back on page two. Q: Can I design both the front and the back? A: Yes. Use the Front and Back toggle above the preview to switch sides. The front carries your name, role and contact block; the back shows a logo or monogram emblem, the company name and optional contact details. Both sides export together in the PDF and with the "Both sides PNG" button. Q: Is my data uploaded anywhere? A: No. The designer is 100 percent client-side. Your text, colours and logo never leave the browser, and the card is drawn on an HTML canvas locally. Your work is auto-saved to this browser's local storage so it is still there when you come back. Q: Can I add my own logo? A: Yes. Upload a PNG, JPG or SVG and it is placed on the front (top-right) and used as the centre emblem on the back. If you do not upload a logo, the back automatically generates a clean monogram from your company or name. Q: How do I send the file to a print shop? A: Most printers accept a PDF or a 300 DPI PNG. Export the PDF for a single file with both sides, or export the front and back PNGs separately if your printer prefers individual images. Ask your printer whether they need bleed; this tool exports edge-to-edge artwork at the trimmed card size. Q: Can I match my exact brand colours? A: Yes. After choosing a template you can override the background, panel, text, accent and muted-text colours with the colour pickers, and pick from five font families. Enter your brand hex values to match an existing identity precisely. #### Letterhead Maker URL: https://geratools.com/letterhead-maker Free letterhead maker. Add your company name, logo, address and contact details, pick a layout and colours, then export a high-resolution PNG header and a print-ready A4 or US Letter PDF page. Runs entirely in your browser — your logo and details are never uploaded. How to use: 1. Enter your company details: Type your company name, optional tagline, address and contact lines. Each new line in the address and contact boxes becomes its own row in the header. 2. Add a logo and pick colours: Upload a PNG, JPG or SVG logo, then choose an accent colour for the divider rule and a text colour to match your brand. 3. Choose a layout and export: Pick a split, left or centered layout, a divider style and font, watch the live preview update, then download a PNG header or a full PDF page. FAQ: Q: What is a letterhead and why do I need one? A: A letterhead is the branded header at the top of a business document. It carries your company name, logo, address and contact details so letters, quotes, invoices and memos look professional and consistent. A reusable letterhead saves you rebuilding the header every time and reinforces your brand on every page. Q: What is the difference between the PNG and PDF export? A: The PNG export gives you just the header strip at high resolution, ideal for pasting into Word, Google Docs, email templates or your own document software. The PDF export produces a complete A4 or US Letter page that already starts with your header plus a sample letter body, so you can print onto it or use it as a template. Q: Is my logo or company information uploaded anywhere? A: No. Everything runs inside your browser. Your logo is read locally as a data URL, the header is drawn on a canvas, and the PDF is generated client-side. Nothing is ever sent to a server, which makes the tool safe for confidential company details. Q: Can I use the PNG header in Microsoft Word or Google Docs? A: Yes. Download the PNG header and insert it into the document header section in Word or Google Docs. Because it is exported at triple resolution it stays sharp when printed. Set it to span the page width and position it at the very top of the page. Q: Will my design be saved if I close the tab? A: Yes. Your latest letterhead design, including text, colours, layout and the uploaded logo, is stored in your browser local storage and reloaded automatically next time you open the tool. Clearing your browser data will remove it. Q: What image formats and sizes work best for the logo? A: PNG with a transparent background gives the cleanest result, but JPG and SVG also work. A square or wide logo around 300 to 600 pixels on its longest side looks crisp in both the PNG and PDF exports. Very tall logos are scaled down to fit the header height automatically. Q: Can I make a letterhead for A4 and US Letter? A: Yes. Switch the paper setting between A4 and US Letter before exporting the PDF. The header layout adapts to the page width, and the exported PDF uses the correct page dimensions for printing in your region. #### Passport & ID Photo Maker URL: https://geratools.com/passport-photo-maker Free passport and ID photo maker. Upload a photo, pick a country size preset (US 2x2, UK 35x45 mm, Schengen, India, China and more), crop to the exact specification and export a print-ready 4x6, A4 or Letter sheet at 300 or 600 DPI. Everything runs in your browser — no upload. How to use: 1. Pick your document size: Choose the country or document preset, such as US 2x2 inch, UK 35x45 mm or Schengen visa. 2. Upload and frame your photo: Upload a head-and-shoulders photo and drag the crop box corners so your face sits between the guide lines. 3. Export a print sheet: Choose a 4x6, A4 or Letter sheet at 300 or 600 DPI and download a ready-to-print PNG with multiple copies and cut guides. FAQ: Q: What passport photo sizes does this tool support? A: It includes presets for the US 2x2 inch (51x51 mm), UK and Schengen 35x45 mm, India passport and PAN, China visa 33x48 mm, Canada 50x70 mm, Australia, Japan 45x45 mm, Brazil, Nigeria DV lottery and a generic ID badge size. Each preset locks the crop to the correct aspect ratio and exports at the exact pixel dimensions for that specification. Q: Is my photo uploaded to a server? A: No. The entire tool runs inside your browser using the HTML canvas. Your photo is decoded, cropped and rendered to a print sheet locally, and nothing is ever sent over the network. Your settings are saved only in your own browser via localStorage. Q: What is the difference between 300 and 600 DPI? A: DPI (dots per inch) sets how many pixels make up each printed inch. 300 DPI is the standard for photo printing and gives a 600x600 pixel image for a US 2x2 photo. 600 DPI doubles the pixel count for extra-sharp results on high-quality printers, at the cost of a larger file. Q: Can I print several copies on one sheet? A: Yes. Choose a 4x6 inch, A4 or US Letter sheet and the tool tiles as many copies of your photo as fit, with a little spacing and optional thin cut guides so you can trim them apart. The live preview shows the grid size and exact number of copies before you export. Q: What background colour should I use? A: Most countries require a plain white or light grey background. Each preset suggests the recommended colour and fills any empty area of the crop with it, but you can override the hex value. The tool does not remove an existing busy background, so start from a photo taken against a plain wall. Q: Does the photo meet official biometric requirements? A: The tool produces the correct print size, aspect ratio, resolution and background fill, which covers the technical specifications. It cannot judge pose, lighting, expression or head proportions, so always check your government guidance on neutral expression, eye position and head size before submitting. #### Photo Collage Maker URL: https://geratools.com/photo-collage-maker Free online photo collage maker. Pick a grid layout, drop a photo into each cell, adjust gaps, background and corner radius, fine-tune zoom and pan, then export a high-resolution PNG. Runs entirely in your browser — no uploads. How to use: 1. Choose a layout: Pick a grid such as 2x2, side-by-side, a feature layout or a 4x4 grid. The preview updates instantly. 2. Add a photo to each cell: Click a cell, then add one or more photos. Drag photos straight from your file manager, or drag a placed photo onto another cell to swap them. 3. Style and frame: Adjust the gap, outer border, corner radius and background colour, then zoom and pan each photo so the framing looks right. 4. Export a PNG: Choose an aspect ratio and output width, then download a high-resolution PNG. Everything is rendered on a canvas in your browser. FAQ: Q: Is this photo collage maker really free and private? A: Yes. It is completely free with no account, no watermark and no upload. Your photos are decoded and drawn on a canvas inside your own browser, and the finished collage is generated locally — no image ever leaves your device. Q: What layouts can I choose from? A: There are eight layouts — a 2x2 grid, side-by-side pair, stacked pair, 3x3 grid, triple strip, a feature-plus-two layout, a hero-plus-three layout and a 4x4 grid. Switching layout keeps the photos you have already added wherever they still fit. Q: How do I rearrange photos after placing them? A: Drag any placed photo onto another cell to swap the two. You can also click a cell to select it, then use the zoom and pan sliders to reframe just that photo without affecting the others. Q: What image formats can I add? A: Any format your browser can decode as an image works, including JPG, PNG, WebP, GIF and most HEIC images on supported browsers. You can add several files at once and they fill the empty cells in order. Q: What size and shape is the exported file? A: You choose an aspect ratio (square 1:1, landscape 4:3, portrait 3:4, wide 16:9 or story 9:16) and an output width from 1080 up to 3000 pixels. The export is a transparent-capable PNG at the full chosen resolution, ideal for printing or social posts. Q: Why does part of my photo get cropped in a cell? A: Each cell fills its space using a cover fit, so the photo is scaled to fill the cell and any overflow is trimmed. Use the zoom and pan sliders for the selected cell to decide exactly which part of the photo shows. #### Quote Image Maker URL: https://geratools.com/quote-image-maker Free quote image maker. Type a quote and author, pick a template, font and background, then export square and Instagram-story PNGs. Runs entirely in your browser — nothing is uploaded. How to use: 1. Type your quote and author: Paste or write the quote in the text box and add the author or source underneath. 2. Pick a template, font and format: Choose one of eight templates, a font, and whether you want a square, story or wide canvas. 3. Export your image: Download the square and story PNGs, or copy the image straight to your clipboard. FAQ: Q: Is the quote image maker free? A: Yes. Every template, font and export size is free with no watermark, no sign-up and no usage limit. The optional watermark field is yours to fill with your own handle if you want one. Q: What sizes can I export? A: You can export a 1080×1080 square (great for an Instagram or LinkedIn post), a 1080×1920 story/reel cover, and a 1200×675 wide image that fits Twitter/X and blog headers. The "Square + Story" button downloads both popular sizes at once. Q: Can I use my own background photo? A: Yes. Upload any image and it is cover-fitted to the canvas with an adjustable dark overlay so the text stays readable. The photo is processed locally and never uploaded anywhere. Q: Will the text fit if my quote is long? A: The quote auto-fits — it wraps to multiple lines and shrinks the font until it fits inside the poster. You can also nudge the text size up or down with the slider for fine control. Q: Are my quote and images private? A: Completely. The poster is drawn on an HTML canvas inside your browser and exported locally. No text, author or photo is ever sent to a server, so even private or client work stays on your device. Q: Can I change the colours of a template? A: Yes. Each template has a tasteful default palette, but you can override the top background, bottom background and text colours with the colour pickers, then reset back to the template at any time. #### Certificate Maker URL: https://geratools.com/certificate-maker Free online certificate maker. Pick a template, add a name, course, date and signatures, then download a print-ready PNG or PDF. Runs entirely in your browser — nothing is uploaded. How to use: 1. Pick a template: Choose Classic, Modern, Elegant, Playful or Corporate. Each sets fonts, colours and border style — switch any time without losing your text. 2. Fill in the details: Type the heading, recipient name, course or achievement, date and organisation. The preview updates live as you type. 3. Add signatures and a seal: Add up to three signers with name and role, toggle the seal, and optionally upload a logo. Tweak the accent colour to match your brand. 4. Export PNG or PDF: Click Download PNG for a high-resolution image or Download PDF for a print-ready A4 sheet in landscape or portrait. FAQ: Q: Is this certificate maker really free? A: Yes. Every template and both export formats (PNG and PDF) are free with no watermark, no sign-up and no usage limit. The whole tool runs in your browser. Q: Are my certificate details private? A: Completely. The name, course, logo and signatures never leave your device — there are no network calls. Your draft is saved only in your own browser via localStorage so you can come back later. Q: What is the difference between the PNG and PDF export? A: PNG is a high-resolution image (rendered at 2x) that is ideal for sharing on screen, email or social media. PDF places the same artwork on an A4 page sized for printing, so it prints cleanly at full size. Q: Can I add my own logo and brand colour? A: Yes. Upload a PNG, JPG or SVG logo and it appears centred above the title. The accent colour picker overrides the template colour for borders, the recipient name, signatures and the seal. Q: Can I make certificates of appreciation or participation, not just achievement? A: Yes. The heading line is fully editable, so you can write Certificate of Appreciation, Certificate of Participation, Certificate of Completion, Award of Excellence or any wording you need. Q: How many signatures can I add? A: Up to three. One signature is centred, two or three are evenly spread across the lower band next to the date. Leave the signatures empty to show just a dated certificate. #### Sprite Sheet Maker URL: https://geratools.com/sprite-sheet-maker Free online sprite sheet maker. Drop image frames, pack them into a grid or tight shelf layout, then export a single sheet PNG and a matching JSON atlas (TexturePacker hash, Phaser array) or CSS sprites. 100% in your browser — no uploads. How to use: 1. Drop your frames: Drag PNG, JPG, GIF or WebP images onto the drop zone, or click to choose them. Each image becomes one frame. 2. Arrange the grid: Pick a uniform grid or tight shelf pack, set the column count and padding, and drag the frame thumbnails to reorder them. 3. Export the sheet and atlas: Click Export sheet PNG for the combined image, then export the JSON atlas (TexturePacker or Phaser) or CSS sprites so your engine knows each frame's coordinates. FAQ: Q: What is a sprite sheet? A: A sprite sheet (or texture atlas) is one large image that packs many smaller images — animation frames, tiles or UI icons — into a single file. Games and websites load one sheet instead of dozens of separate requests, which is faster and uses GPU memory more efficiently. A companion data file lists the x, y, width and height of every frame so code can crop the right region. Q: What does the JSON atlas contain? A: It lists every frame by name with its pixel rectangle (x, y, w, h), the original source size, and sheet metadata (image filename and total size). The TexturePacker JSON-hash format loads directly into Phaser, PixiJS and many other engines; the array variant matches Phaser 3's atlas loader. CSS export instead gives you background-position rules for web sprites. Q: Does this tool upload my images anywhere? A: No. Every frame is decoded and composited onto a canvas entirely inside your browser. Nothing is sent to a server, so you can safely pack unreleased game art or private icons. Q: What is the difference between uniform grid and tight pack? A: Uniform grid gives every frame the same cell size (the largest frame's dimensions) and centres each image — ideal for animation frames that must stay aligned. Tight pack uses a shelf algorithm to nest frames of different sizes with minimal wasted space, which is better for mixed UI icons where alignment does not matter. Q: Why would I enable power-of-two dimensions? A: Older GPUs and some mobile engines require texture dimensions that are powers of two (256, 512, 1024 and so on). Enabling the option rounds the final sheet up to the next power of two on each axis. The packing efficiency readout shows how much of the sheet is actually used. Q: What image formats can I import and export? A: You can import any format the browser can decode — PNG, JPG, GIF, WebP and usually AVIF. The exported sheet is always a lossless PNG so transparency is preserved. The atlas is plain JSON or CSS text you can open in any editor. #### Coupon & Voucher Maker URL: https://geratools.com/coupon-maker Free coupon and voucher maker. Set your offer, code and expiry, pick a template, then download a print-ready PNG. Runs entirely in your browser — nothing is uploaded. How to use: 1. Pick a template: Choose Ticket, Modern, Festive, Premium or Minimal to set the overall look. 2. Set the offer and code: Type the headline offer (like '25% OFF'), a caption, and the coupon code customers will enter. 3. Add an expiry and terms: Set the 'valid until' date and a small-print terms line so the coupon reads as a real voucher. 4. Export the PNG: Download a high-resolution PNG (white card or transparent cut-out) ready to print or share. FAQ: Q: Is the coupon maker really free? A: Yes. Every feature — all templates, the logo upload, colour controls and PNG export — is completely free with no sign-up, watermark or usage limit. Q: Are my coupon details uploaded anywhere? A: No. The coupon is drawn on an HTML canvas inside your browser and the PNG is generated locally. No text, logo or image ever leaves your device, and there is no network request at all. Q: What size and quality is the exported image? A: The PNG is rendered at twice the on-screen resolution (2000 by 840 pixels) so it stays crisp when printed or shown on high-density screens. You can choose a white-card background or a transparent cut-out that follows the coupon's ticket shape. Q: Does the barcode on the stub actually scan? A: No — the bars on the tear-off stub are a decorative pattern generated from your code, not a scannable barcode. The human-readable code printed beneath it is what customers type at checkout. If you need a real scannable code, generate a QR code separately and place it on the stub area. Q: Can I add my own logo and brand colours? A: Yes. Upload a PNG, JPG or SVG logo and it appears next to your brand name. You can also override the accent colour (used for the offer and code) and the background colour independently of the chosen template. Q: How do I print or share the coupon? A: Download the PNG and drop it into any document, email, social post or print layout. The white-card export prints cleanly on standard paper; the transparent version is ideal for layering over a flyer or web banner. #### ID & Membership Card Maker URL: https://geratools.com/id-card-maker Free online ID and membership card maker. Design both sides of a standard CR80 card, add a photo and custom fields, then export crisp PNGs and a print-ready PDF sheet with crop marks. Runs entirely in your browser — no photos or data are uploaded. How to use: 1. Pick a template and colours: Choose Classic, Side band, Minimal or Event badge, then set the accent and background colours to match your brand. 2. Add the organisation, holder and photo: Type the organisation name, cardholder name and ID number, then upload a photo that is automatically cropped to fit. 3. Fill in front and back fields: Add custom label and value rows for the front and back, plus a terms note on the reverse. 4. Export PNG or a print sheet: Download each side as a high-resolution PNG, or generate a print-ready PDF sheet sized to CR80 cards with crop marks. FAQ: Q: What size card does this make? A: It designs a standard CR80 card, the same size as a credit card or driving licence at 85.6 by 54 mm. The canvas renders at roughly 300 DPI so PNG exports and the PDF print sheet stay sharp when printed or laminated. Q: Are my photo and details uploaded anywhere? A: No. Everything runs in your browser. The photo you choose is read locally, drawn onto a canvas, and never sent to any server. Your card details are saved only in this browser's local storage so you can come back later. Q: How do I print the cards at the right size? A: Use the Print sheet (PDF) button. It lays out front-and-back pairs on A4 at exact CR80 dimensions with crop marks at each corner. Print at 100 percent (no fit-to-page scaling) and cut along the marks. Q: Can I make staff, student or event badges? A: Yes. The four templates cover most cases: Classic and Minimal suit membership and staff cards, Side band suits corporate ID, and Event badge gives a large centred photo and name for conferences or visitors. Q: Can I design both the front and the back? A: Yes. Switch between Front and Back in the preview. The back includes a magnetic-stripe style strip, the ID number, your own label-and-value rows, a signature line and an editable terms note. Q: What format are the exports? A: Each side exports as a transparent-corner PNG image, and the multi-card layout exports as a PDF. Both are generated entirely on your device, so there are no watermarks, accounts or limits. #### Seating Chart Maker URL: https://geratools.com/seating-chart-maker Free seating chart maker for weddings, banquets and events. Add round or rectangle tables, drag them into place, assign guests to numbered seats, colour-code by group and export a print-ready PNG — all in your browser. How to use: 1. Add your tables: Click "Round table" or "Rectangle table" for each table in the room, then set how many seats each one has. 2. Drag tables into the room layout: Grab any table on the floor plan and drag it to match your venue. The grid helps you keep things aligned. 3. Add your guests: Type each guest name in the guest list, optionally with a group like Family or Friends so they get a colour. 4. Assign guests to seats: Click a numbered seat and pick a guest from the dropdown, or hit "Auto-seat" to fill empty seats in order. 5. Export your chart: Click "Download PNG" for a print-ready chart, or "Export JSON" to save the plan and reopen it later. FAQ: Q: Is this seating chart maker free? A: Yes, completely free with no sign-up. Everything runs in your browser, so there is no account, no watermark and no limit on the number of tables or guests you can add. Q: Can I use it for weddings and large banquets? A: Absolutely. You can add as many round or rectangle tables as your venue needs, set seat counts from 1 to 24 per table, and colour-code guests by family, friends or wedding side. It works for weddings, galas, conferences and dinner parties alike. Q: How do I assign a guest to a seat? A: Click any numbered seat on the floor plan, then choose a guest from the dropdown. Each guest can only sit in one seat, so picking them for a new seat automatically moves them from their old one. Q: What does the Auto-seat button do? A: It takes every guest who is not yet seated and drops them into the next available empty seats, table by table, in order. It is a fast way to get a first draft that you can then fine-tune by hand. Q: Will my seating plan be saved if I close the tab? A: Yes. Your chart is stored in your browser using localStorage, so it is still there when you come back. For a permanent backup or to move it to another device, use Export JSON and re-import the file later. Q: Is my guest list private? A: Completely. No names, tables or images ever leave your device — there is no server and no network request. The PNG and JSON files are generated locally and only saved when you click download. #### ASCII Art Generator URL: https://geratools.com/ascii-art-generator Free ASCII art generator. Upload a photo or logo and convert it into text art with adjustable width, character ramps, brightness, contrast and colour. Copy it, download a .txt, or save a PNG — all in your browser. How to use: 1. Upload an image: Drag a photo, logo or screenshot onto the drop zone, or click to choose a file. Nothing leaves your browser. 2. Set the width: Drag the width slider to choose how many characters wide the output is — higher means more detail and a larger result. 3. Tune the look: Pick a character ramp and adjust brightness, contrast, invert or colour until the art reads clearly. 4. Export it: Copy the text, download a .txt file, or save a PNG image of the ASCII art. FAQ: Q: How does an image become ASCII art? A: The picture is drawn onto a small canvas sized to your chosen character width. Each pixel's brightness (its perceptual luminance) is measured, then mapped to a character from a ramp that runs from dark to light — so dark areas become dense glyphs like @ or # and bright areas become spaces or dots. Q: Why is the output wider than it is tall? A: Monospace characters are about twice as tall as they are wide, so the tool samples half as many rows as columns. That keeps your image from looking vertically squashed when rendered as text. Q: Which character ramp should I use? A: The Standard 70-level ramp gives the most photographic detail. Block shades (light to dark Unicode blocks) look crisp for logos. Simple, Binary and Dots ramps are great when you need plain ASCII that pastes cleanly into code comments, terminals or chat. Q: Can I get coloured ASCII art? A: Yes. Tick "Colour preview and PNG" and each character keeps the colour of the pixel it came from. Plain copied text stays monochrome (clipboards do not carry colour), but the downloaded PNG preserves the colours on a dark background. Q: What can I do with the result? A: Copy it into a README, code comment, email signature, forum post or terminal banner; download a .txt to keep the raw characters; or save a PNG to share the art as an image on social media. Q: Are my images uploaded anywhere? A: No. The whole conversion happens locally with the HTML canvas API. Your image never leaves your device and nothing is sent to a server. #### Batch QR Code Generator URL: https://geratools.com/batch-qr-generator Free batch QR code generator. Paste a list of URLs or a CSV, generate one QR per row, customise size, colour, error correction and format, then download every code plus a manifest as a single zip — 100% in your browser. How to use: 1. Choose your input format: Pick one payload per line for a quick list, or CSV mode to control each filename with a header row of filename and content. 2. Paste your data: Drop in your URLs, Wi-Fi strings, phone numbers or any text. Each non-empty row becomes its own QR code. 3. Tune size, colour and format: Set the pixel size, quiet margin, error-correction level, foreground and background colours, and choose PNG or SVG output. 4. Download the zip: Click download to get every QR code plus a manifest.csv mapping each file back to its payload — all generated locally. FAQ: Q: How many QR codes can I generate at once? A: You can generate up to 500 codes in a single batch. The on-screen grid previews the first 30 for speed, but every queued row is written into the downloaded zip. For larger jobs, split your list into batches of 500 and run them one after another. Q: What is the difference between lines mode and CSV mode? A: In lines mode each non-empty line becomes one QR code and filenames are auto-numbered with your chosen prefix, like qr-001.png. In CSV mode the first row is a header containing a content column and an optional filename column, so you control exactly what each file is called. Q: Should I download PNG or SVG QR codes? A: PNG is a fixed-resolution raster image that works everywhere and is ideal for screens, slides and most print jobs. SVG is a vector format that stays razor-sharp at any size, so choose it for large-format printing, signage or when a designer needs to rescale the code. Q: What does the error-correction level do? A: Error correction lets a scanner still read the code when part of it is damaged, dirty or covered by a logo. Higher levels (Q and H) recover more of the code but pack in more modules, making the pattern denser. Use L or M for clean digital codes and H when you overlay a logo or print on a rough surface. Q: What is the manifest.csv file in the zip? A: The manifest is a spreadsheet-friendly index listing every generated filename next to the exact text or URL it encodes. It lets you audit a large batch, re-import the data later, or hand a print shop a clear map of which code goes where. Q: Is my data uploaded anywhere? A: No. Every QR code is rendered with an in-browser library and zipped on your own device using client-side JavaScript. Nothing you paste — links, Wi-Fi passwords or contact details — is ever sent to a server, which makes the tool safe for sensitive batches. #### Contact Sheet Maker URL: https://geratools.com/contact-sheet-maker Free contact sheet maker: drop dozens of images and get a tidy thumbnail grid with filenames and numbering, then download it as a single PNG. Columns, thumbnail size, fit, colours and density are all adjustable. Runs 100% in your browser — no upload. How to use: 1. Add your images: Drag a folder of photos onto the drop zone or click to pick files. Everything stays on your device. 2. Lay out the grid: Choose the number of columns, thumbnail size, gap and outer margin until the sheet looks right in the live preview. 3. Caption and reorder: Toggle filenames and numbering, drag thumbnails to reorder them, or sort A to Z. 4. Export the PNG: Pick 1x or 2x density and click Download PNG to save the whole sheet as one image. FAQ: Q: What is a contact sheet? A: A contact sheet (also called a proof sheet or index print) is a single page showing small thumbnails of many photos side by side, usually with each frame labelled by filename or number. Photographers use them to review a shoot at a glance, share a selection with clients, or keep a printed index of an archive without opening every file. Q: Are my photos uploaded anywhere? A: No. Every image is read locally with your browser's File API, decoded in memory and drawn onto a canvas on your own machine. Nothing is sent to a server, so even confidential or unreleased photos stay private. Q: How many images can I put on one sheet? A: There is no fixed limit — the grid grows downward as you add more. In practice you are bounded only by your device's memory and the maximum canvas size your browser allows. For very large shoots, split them into batches of a few hundred or reduce the thumbnail size and export density. Q: Can I change the order of the photos? A: Yes. Drag any thumbnail in the tray to a new position to reorder it, or click Sort A to Z to order them by filename using natural numeric sorting (so image2 comes before image10). Q: What is the difference between Contain and Cover fit? A: Contain scales each photo so the whole image is visible inside its cell, leaving the cell colour around the edges where aspect ratios differ. Cover scales the photo to fill the entire cell and crops the overflow, giving a uniform edge-to-edge grid with no gaps. Q: Why would I choose 2x export density? A: 2x renders the sheet at double the pixel dimensions, which keeps thumbnails and captions crisp when printed or viewed on high-resolution (retina) screens. Use 1x if you want a smaller file for quick on-screen sharing. #### Sprite Sheet Slicer URL: https://geratools.com/sprite-sheet-slicer Free online sprite sheet slicer. Upload a sprite sheet, cut it into individual frames by rows and columns or by fixed cell size, deselect blank cells, optionally trim transparent edges, then download every frame as a ZIP with a JSON manifest. 100% in your browser — nothing is uploaded. How to use: 1. Upload your sprite sheet: Drag a PNG, JPG, GIF or WebP sheet onto the drop zone or click Choose image. The tool reads its pixel dimensions instantly. 2. Choose how to slice: Pick By rows and columns to enter a grid count, or By cell size to enter the exact pixel width and height of one frame. Add margin and spacing if the sheet has padding between cells. 3. Refine the selection: The preview overlays the grid on your sheet. Click any cell to exclude blank or unwanted frames, and turn on Trim transparent edges to crop each frame tight. 4. Export the frames: Click Download as ZIP to get every selected frame as a numbered PNG plus a frames.json manifest, or use the download icon under a single thumbnail to save just that frame. FAQ: Q: What is a sprite sheet slicer? A: A sprite sheet slicer takes one large image that packs many smaller pictures — animation frames, tiles or icons — and cuts it back into separate image files. You tell it how the cells are laid out (a grid of rows and columns, or a fixed cell size in pixels) and it crops each region from the sheet into its own PNG. This tool runs the whole process on a canvas inside your browser, so a 256-frame sheet becomes 256 ready-to-use PNGs without any server round trip. Q: Should I slice by grid or by cell size? A: Use By rows and columns when you know the layout — for example a 4 by 4 walk-cycle sheet — and the tool divides the sheet evenly into that many cells. Use By cell size when you know each frame is, say, 32 by 32 pixels but you are not sure how many fit; the tool figures out the column and row count from the sheet width and height. Both modes account for any outer margin and inter-cell spacing you enter. Q: What do margin and spacing do? A: Margin is the blank border around the outside of the whole sheet before the first cell begins, set separately for the X and Y axes. Spacing is the gap between adjacent cells. Many exporters add a one or two pixel gutter to stop neighbouring frames bleeding into each other; set Spacing X and Spacing Y to that gutter width so each cell lands exactly on its art. Q: How does Trim transparent edges work? A: With trimming on, the slicer scans each frame for fully transparent pixels around the edges and crops them away, leaving the tightest rectangle that still contains visible art. This is handy when you want frames sized to their content rather than to a uniform cell — for packing into another atlas, for instance. Frames that are entirely transparent are left at their full cell size. Trimming only affects formats with an alpha channel, so it has no effect on opaque JPGs. Q: What is in the downloaded ZIP? A: The ZIP contains one PNG per selected frame, named from your pattern (frame_0.png, frame_1.png and so on), inside a folder named after your sheet. It also includes a frames.json manifest listing every frame name with its source x, y, width, height, row and column, plus the slice settings used. The manifest makes the cut reproducible and lets you re-import the coordinates into a game engine or build script. Q: Is my image uploaded anywhere? A: No. The sheet is decoded and sliced entirely on your device using the browser canvas and the JSZip library running locally. Nothing is sent over the network, so you can safely cut unreleased game art, private icon sets or client assets. #### Nonogram Generator (Picross / Hanjie Puzzles) URL: https://geratools.com/nonogram-generator Free nonogram (Picross / Hanjie) generator. Pick a grid size and difficulty, solve the puzzle in your browser, reveal the solution, and export a printable PDF with a separate answer key. Every puzzle is guaranteed uniquely logic-solvable. Runs 100% in your browser — nothing is uploaded. How to use: 1. Choose a grid size: Pick 5×5 for a quick warm-up, 10×10 for a standard puzzle, or 15×15 for a real challenge. 2. Set the difficulty: Easy grids are denser and easier to read; medium and hard leave more gaps, so the number clues constrain fewer cells and force more deduction. 3. Solve in the browser: Left-click a cell to fill it and right-click to mark a cell you have ruled out with an X. The board tells you the moment every row and column matches its clues. 4. Reveal or regenerate: Stuck? Use Reveal solution to compare. Want a different layout? Press New puzzle, or type a specific seed to rebuild the exact same puzzle later. 5. Export a printable PDF: Download a clean two-page PDF — an empty puzzle to solve on paper plus a separate answer key — sized for A4 with bold every-fifth-line guides. FAQ: Q: What is a nonogram? A: A nonogram — also called Picross, Hanjie, Griddler, or paint-by-numbers — is a grid logic puzzle. Numbers beside each row and above each column tell you the lengths of the consecutive runs of filled cells in that line, in order, with at least one gap between runs. You deduce which cells are filled until a hidden picture or pattern emerges. No guessing is required for a well-formed puzzle. Q: Are the generated puzzles always solvable by logic? A: Yes. After building a random grid and deriving its clues, the tool runs a line-by-line logic solver across every row and column repeatedly. It only accepts a puzzle if that pure-deduction solver fully completes the grid and the result exactly matches the original — which also guarantees the solution is unique. Puzzles that would need guessing are discarded and regenerated. Q: How do the row and column number clues work? A: Each clue lists the run lengths in that line from left to right (rows) or top to bottom (columns). A clue of 3 1 2 means a run of three filled cells, then at least one empty cell, then a single filled cell, another gap, and finally a run of two. A clue of 0 means the line is entirely empty. Q: What do the difficulty levels actually change? A: Difficulty controls how densely the grid is filled. Easy puzzles fill roughly 60% of cells, so long runs make clues easy to place. Harder levels fill closer to 40%, leaving scattered short runs that pin down fewer cells per clue and demand cross-referencing rows against columns to make progress. Q: Can I recreate the exact same puzzle later? A: Yes. Every puzzle is built from a numeric seed shown on screen and printed on the PDF. Type the same size, difficulty, and seed and you will rebuild an identical puzzle — handy for sharing a specific puzzle with a friend or printing a class set where everyone solves the same grid. Q: Is anything I do uploaded or tracked? A: No. Generation, solving, and PDF export all happen entirely inside your browser using client-side JavaScript. Your grid size, difficulty, and seed are saved only in this browser's local storage so the tool reopens where you left off. Nothing is ever sent to a server. #### SVG Wave Generator URL: https://geratools.com/svg-wave-generator Free SVG wave generator. Stack layered sine waves with custom amplitude, wavelength, colour and opacity, animate them, then download a clean SVG or copy the markup. 100% in your browser. How to use: 1. Set the canvas size and edge: Choose the width and height of the divider and whether the waves anchor to the bottom (footer) or top (header) edge. 2. Shape each layer: Adjust amplitude, wavelength, phase, colour and opacity per layer. Add up to eight layers and reorder them to control which sits in front. 3. Animate and export: Tick Animate to scroll the waves horizontally, then Download SVG or Copy markup to drop the result straight into your page. FAQ: Q: What is an SVG wave divider used for? A: A wave divider is a curved SVG shape placed between two page sections — most often at the top or bottom of a hero banner or footer. Because it is vector, it scales to any width without blurring and stays a tiny file. Designers use them to soften the hard horizontal line where two background colours meet, giving a page a modern, fluid look. Q: How do amplitude and wavelength change the wave? A: Amplitude is the peak height of the wave in pixels — bigger amplitude means taller crests and deeper troughs. Wavelength is the horizontal distance of one full crest-to-crest cycle, so a short wavelength packs more ripples across the canvas while a long one gives a single lazy swell. Phase shifts the wave left or right, which is how stacked layers are offset so they do not line up. Q: Why stack multiple layers? A: Layering two or three semi-transparent waves of different amplitude, wavelength and colour creates depth and a sense of motion even when static. The back layer is usually the most opaque, with lighter layers in front. This is the same technique behind the popular gradient hero waves you see on SaaS landing pages. Q: Is the animation real or just a preview? A: It is real. When you enable Animate, the exported SVG embeds a SMIL animateTransform element that scrolls the wave horizontally and loops seamlessly — no JavaScript or CSS required. The wave is drawn twice side by side and translated by one canvas width so the loop has no visible seam. Static SVGs omit the animation entirely. Q: Will the exported SVG work in my website or email? A: The download is a standard, self-contained SVG file you can use as an inline element, a CSS background, or an img source on any website. Animated (SMIL) waves play in all current browsers but not inside most email clients, so choose a static export for email. The markup uses preserveAspectRatio="none" so it stretches cleanly to any container width. Q: Is anything uploaded to a server? A: No. Every wave is computed and rendered in your browser using plain SVG path maths, and your settings are saved only in this browser via local storage. Nothing is sent anywhere, so you can use it offline and on private work without any privacy concern. ### Color from Image #### ICC Color Profile Viewer URL: https://geratools.com/icc-profile-viewer Free ICC color profile viewer. Reads the embedded ICC profile from a JPEG, PNG or TIFF in your browser, decodes the profile header — color space, PCS, device class, rendering intent, description — and lists the tag table. No image is uploaded. How to use: 1. Choose an image: Select a JPEG or TIFF that may carry an embedded color profile. The file is read in your browser and never uploaded. 2. Read the profile header: The tool decodes the ICC header and shows the color space, profile connection space, device class, rendering intent, and description. 3. Review the tag table: Each tag in the profile is listed with its signature, byte offset, and size so you can see exactly what the profile contains. FAQ: Q: What is an ICC profile? A: An ICC profile is a standardized data block, defined by the International Color Consortium, that describes how a device or color space reproduces color. Embedding one in an image lets color-managed software display the same colors consistently across monitors and printers. Q: Which image formats are supported? A: JPEG profiles stored in APP2 ICC_PROFILE markers and TIFF profiles in tag 34675 are decoded directly. PNG profiles live in a zlib-compressed iCCP chunk; the tool detects them but cannot decompress without a library, so it tells you to try a JPEG or TIFF. Q: What does rendering intent mean? A: Rendering intent is how out-of-gamut colors are mapped when converting between color spaces. The four ICC intents are perceptual, media-relative colorimetric, saturation, and ICC-absolute colorimetric. The viewer reads the value stored in the profile header. Q: Why does my image show no ICC profile? A: Many images have no embedded profile and are assumed to be sRGB. That is normal for web images and screenshots. The viewer reports when no ICC_PROFILE marker, iCCP chunk, or TIFF profile tag is present. Q: Is my image uploaded to a server? A: No. The image is read locally with the browser FileReader API and the profile bytes are decoded in JavaScript. The picture never leaves your device, which is ideal for confidential or unpublished images. #### Average Colour of an Image URL: https://geratools.com/image-average-color Free average image colour tool. Upload any image and get its mean colour — averaged across every visible pixel — as HEX, RGB and HSL, plus WCAG relative luminance to tell light from dark. Runs in your browser; nothing is uploaded. How to use: 1. Upload an image: Choose any image file. It is drawn to a small canvas in your browser. 2. Read the average: The tool sums every visible pixel and divides to get the mean colour, shown as a swatch alongside the original. 3. Copy the value: Copy the average as HEX, RGB or HSL for use as a placeholder or theme colour. FAQ: Q: How is the average colour calculated? A: The image is drawn onto a canvas and the red, green and blue channels of every non-transparent pixel are summed and divided by the pixel count. Fully transparent pixels are skipped so they do not drag the average toward black. Q: Why downscale the image first? A: The mean of the pixels is essentially unchanged by resolution, so the image is scaled down before sampling to keep the calculation fast. A 4000px photo and its 400px copy give effectively the same average. Q: What is the luminance value for? A: It is the WCAG relative luminance of the average colour, from 0 (black) to 1 (white). A value above 0.5 means the image is overall light, below 0.5 means overall dark — handy for deciding whether to overlay light or dark text. Q: Is my image uploaded? A: No. All pixel reading and averaging happens locally on a canvas in your browser. The image is never transmitted. #### Nearest CSS Colour Name Finder URL: https://geratools.com/nearest-css-color-name Free nearest CSS colour name finder. Enter any hex or RGB colour and get the closest of the 148 CSS named colours by perceptual distance, an exact-match flag, and the next four closest alternatives. Runs entirely in your browser. How to use: 1. Enter a colour: Type a hex (#RGB or 2. Read the nearest name: The closest CSS named colour is shown with its swatch, hex value, and whether it is an exact match. 3. Copy or compare: Copy the keyword, or scan the next four closest names to choose the best fit. FAQ: Q: Which colour names does this use? A: It uses the 148 named colours defined in the CSS Color Module Level 4 specification — the standard keyword set every browser recognises, such as tomato, steelblue and rebeccapurple. It is the real W3C list, not an invented palette. Q: How is the nearest colour chosen? A: The tool measures distance with the redmean formula, a weighted RGB metric that approximates human colour perception better than plain Euclidean distance. The named colour with the smallest distance to your input is the match. Q: What does the exact-match flag mean? A: If your colour is identical to a named colour, the distance is essentially zero and the tool marks it as an exact match. Otherwise it shows the perceptual distance so you know how close the nearest name is. Q: Can I enter an RGB value instead of hex? A: Yes. Both hex (3- or 6-digit) and rgb() syntax are accepted, and the colour picker fills the field for you. #### Color Contrast Grid URL: https://geratools.com/color-contrast-grid Free color contrast grid. Paste a whole palette and get an N×N matrix of every foreground/background combination, with exact WCAG 2.1 contrast ratios and AA/AAA pass marks for normal and large text. Runs entirely in your browser — nothing is uploaded. How to use: 1. Paste your palette: Drop your colours in as hex, rgb() or names — one per line or comma-separated — then choose Replace or Add to palette. 2. Read the matrix: Each row is a background and each column is a text colour; every cell shows the exact contrast ratio plus AA/AAA badges. 3. Fix the failures: Use Copy failing pairs to grab every combination below 4.5:1, or export the whole grid to CSV for your design system docs. FAQ: Q: What is a color contrast grid? A: A color contrast grid is a matrix that pairs every colour in a palette against every other colour and shows the WCAG contrast ratio for each combination. Instead of checking one foreground and background at a time, you see the whole palette scored at once, which makes it obvious which text/background pairings are safe to use and which fail accessibility requirements. Q: What contrast ratio do I need to pass WCAG? A: WCAG 2.1 requires a contrast ratio of at least 4.5:1 for normal body text and 3:1 for large text to meet level AA. To reach the stricter AAA level you need 7:1 for normal text and 4.5:1 for large text. Large text means roughly 18.66px bold or 24px and above. This grid shows both the AA and AAA result for each pair so you can target whichever level your project needs. Q: How is the contrast ratio calculated? A: The ratio is (L1 + 0.05) / (L2 + 0.05), where L1 and L2 are the relative luminances of the lighter and darker colours. Relative luminance is computed by linearising each sRGB channel and weighting them 0.2126 red, 0.7152 green and 0.0722 blue, exactly as defined in WCAG 2.1. The result ranges from 1:1 (identical colours) to 21:1 (pure black on pure white). Q: What colour formats can I paste? A: You can paste 6-digit and 3-digit hex (with or without the # prefix), 8-digit hex with alpha (the alpha is ignored for contrast), rgb() and rgba() values, and common CSS colour names such as navy, teal or crimson. Mix formats freely and separate them with new lines, commas, semicolons or spaces. Q: Does this tool consider colour blindness? A: WCAG contrast ratios are based on luminance, not hue, so a passing ratio already helps many users with colour vision deficiencies because it guarantees a brightness difference. However contrast alone does not catch every issue — never rely on colour as the only way to convey meaning, and pair this tool with a dedicated colour-blindness simulator for a fuller check. Q: Is my palette uploaded anywhere? A: No. Every contrast ratio is calculated in your browser with JavaScript, and your palette is saved only to this browser's local storage so it is still there when you come back. Nothing is sent to a server, which makes the tool safe for unreleased brand colours and works fully offline. Q: How many colours can I add? A: You can add up to 16 colours. A 16-colour palette already produces 240 distinct foreground/background pairs, which is plenty for a design-system audit, and keeping the cap here keeps the matrix readable on screen and quick to scan. #### Image Color Extractor URL: https://geratools.com/image-color-extractor Free image color extractor. Upload a photo or logo and instantly get its dominant colour palette with hex, RGB and HSL codes, proportional shares, plus PNG, CSS-variable and JSON export. Runs entirely in your browser — your image is never uploaded. How to use: 1. Upload or drop an image: Choose any PNG, JPG, WebP or GIF, or drag it onto the drop zone. The image is decoded locally in your browser. 2. Choose how many colours you want: Use the slider to set a palette of 2 to 12 colours, and optionally ignore near-white and near-black pixels for a more vibrant scheme. 3. Copy or export the palette: Click any swatch to copy its hex, or copy RGB and HSL values, then export the whole palette as a PNG strip, CSS variables or JSON. FAQ: Q: How does the colour extractor find the dominant colours? A: It draws your image to a canvas, downsamples it to a small sampling grid, then runs a median-cut quantisation. Median-cut repeatedly splits the colour space along its widest channel until it has the number of buckets you asked for, then averages each bucket — this gives perceptually representative colours rather than just the single most-common pixel. Q: Is my image uploaded to a server? A: No. Everything happens in your browser using the HTML canvas API. The image bytes are read locally, the palette is computed on your device, and nothing is ever sent over the network — so it works offline and keeps private photos private. Q: What colour formats can I copy or export? A: Each swatch shows its hex code, RGB and HSL values, and you can click any of them to copy. You can also copy all hex codes at once, or export the palette as a labelled PNG strip, a block of CSS custom properties, or a JSON file with hex, RGB, HSL and each colour's share. Q: What does the percentage next to each colour mean? A: It is the share of sampled pixels that fell into that colour bucket, so it approximates how much of the image that colour occupies. The proportional bar at the top of the palette visualises the same shares as band widths. Q: What is the vibrant or ignore-edges option for? A: Many photos are dominated by large areas of near-white background or near-black shadow. Turning on the ignore option drops pixels at the extreme light and dark ends before quantising, so the palette focuses on the saturated, characterful colours instead of grey and off-white. Q: What image formats are supported? A: Any format your browser can decode as an image works — typically PNG, JPG, WebP, GIF, BMP and often AVIF. Animated GIFs are sampled on their first frame. Transparent pixels are skipped so they do not pollute the palette. #### Color Name Finder URL: https://geratools.com/color-name-finder Pick or type any colour and get the closest CSS named colour by perceptual ΔE, its HEX/RGB/HSL codes, complementary, analogous, triadic and split-complementary shades — all copyable, all in your browser. How to use: 1. Choose your colour: Use the colour picker, type a hex code like 2. Read the nearest name: The big preview shows whether your colour is an exact CSS named colour or the closest match with its perceptual ΔE distance. 3. Grab the harmonies: Copy the HEX, RGB or HSL of the complementary, analogous, triadic and split-complementary shades, or click Use to make any of them the new base. FAQ: Q: How does it find the nearest colour name? A: It converts your colour and all 148 CSS named colours into CIE Lab space and measures the perceptual distance (ΔE). Lab distance tracks how different two colours look to the human eye far better than raw RGB distance, so the suggested name is the one most people would actually call it. Q: What does the ΔE number mean? A: ΔE is the perceptual distance between your colour and the named match. A ΔE near 0 means they are visually identical; under about 2 is barely distinguishable; 2 to 10 is a clear but related shade; above that the names are just the closest available label rather than a true match. Q: What is a complementary colour? A: The complementary colour sits directly opposite on the colour wheel, 180 degrees away in hue. It gives the highest contrast pairing with your base colour and is widely used for accents, call-to-action buttons and anything that needs to pop against the main colour. Q: What is the difference between analogous, triadic and split-complementary? A: Analogous colours sit 30 degrees either side of your hue for a calm, cohesive palette. Triadic uses three evenly spaced hues 120 degrees apart for vivid, balanced schemes. Split-complementary takes the two hues either side of the complement for high contrast that is easier to balance than a straight complementary pair. Q: Which colour names are supported? A: All 148 standard CSS named colours, from aliceblue and cornflowerblue to rebeccapurple and yellowgreen. You can type any of them in the input box and the tool will load that exact colour, or it will name the closest one when you pick a custom shade. Q: Is my colour data sent anywhere? A: No. Every conversion, distance calculation and harmony is computed entirely in your browser with no network calls. Your recent colours are saved only in this browser's local storage, and you can clear them at any time. ### More Image Tools #### EXIF Scrubber (Privacy Cleaner) URL: https://geratools.com/exif-scrubber Remove EXIF, GPS location, IPTC, and XMP metadata from a photo before posting it online. The image is redrawn on a canvas so all hidden data is discarded, then offered as a clean JPEG or PNG. Nothing is uploaded. How to use: 1. Choose a photo: Select any JPEG, PNG, or WebP image. It is processed entirely in your browser and never uploaded. 2. See what was hidden: The tool reports whether EXIF, GPS coordinates, or an XMP packet were present in the original file. 3. Download the clean copy: Pick JPEG or PNG output and download a pixel-identical image with every metadata block removed. FAQ: Q: How does redrawing remove metadata? A: EXIF, GPS, and XMP live in separate marker blocks alongside the pixel data. Drawing the image onto an HTML canvas and re-exporting it emits only the raw pixels, so every metadata block is left behind and cannot be recovered. Q: Does this change how my photo looks? A: The pixels are copied one-for-one. If you export as PNG the result is lossless and visually identical. JPEG re-encoding is visually near-identical at high quality; lower the quality slider only if you also want a smaller file. Q: Is the most dangerous data the GPS location? A: Often yes. Many phone cameras embed exact latitude and longitude in the EXIF GPS sub-directory, which can reveal your home or location. This tool removes it along with all other metadata. Q: Is anything uploaded to a server? A: No. Reading, inspecting, and re-encoding all happen locally using the browser File and Canvas APIs. The photo and its metadata never leave your device. Q: Which formats are supported? A: Any image your browser can decode (JPEG, PNG, WebP, GIF, and more) can be loaded. Output is offered as JPEG or lossless PNG. #### Image Diff (Pixel-Level) URL: https://geratools.com/image-diff Free pixel-level image diff tool that compares two images on a canvas in your browser, computing the exact per-pixel difference, reporting the mismatch percentage and rendering changed pixels in red. Ideal for regression screenshots. No upload. How to use: 1. Load both images: Pick the baseline image and the comparison image. Each is drawn to a canvas so its raw pixels can be read; the files never leave your device. 2. Set the tolerance: Choose how much per-channel difference counts as a real change. A small threshold absorbs JPEG noise and anti-aliasing while still catching genuine differences. 3. Read the diff: The tool reports the percentage of pixels that differ and renders a diff image where changed pixels are painted red over a dimmed copy of the original. FAQ: Q: How is the per-pixel difference measured? A: For each pixel the tool reads the red, green, blue and alpha channels from both images and computes a color distance. If that distance exceeds your tolerance, the pixel is counted as different and painted red in the output. The mismatch percentage is differing pixels divided by total pixels. Q: What if the two images are different sizes? A: Pixel comparison requires matching dimensions, so the tool compares the overlapping region using the smaller width and height and tells you the sizes differ. Resize one image to match the other for a full comparison. Q: Why set a tolerance instead of exact match? A: Lossy formats like JPEG and anti-aliased text introduce tiny color variations that are invisible to the eye but differ bit-for-bit. A small tolerance ignores that noise so the diff highlights only meaningful changes, the way visual regression tools do. Q: Can it ignore anti-aliasing? A: The tolerance threshold is the main control: raising it suppresses single-pixel edge differences caused by anti-aliasing and sub-pixel rendering. For pixel-perfect assets, set the tolerance to zero to catch every change. Q: Are my images uploaded anywhere? A: No. Both images are decoded and compared entirely in your browser using the Canvas API. No image data is transmitted, so the tool works offline and your screenshots stay private. #### Image Steganography Detector URL: https://geratools.com/image-steganography-detector Free image steganography detector. Loads a PNG or BMP and runs a chi-squared statistical test on pixel least-significant bits via Canvas to estimate the likelihood of hidden LSB-embedded data. It reports a likelihood, not the payload. Runs entirely in your browser. How to use: 1. Load an image: Choose a PNG or BMP file — lossless formats are required because JPEG compression destroys LSB data. 2. Run the analysis: The tool reads every pixel's least-significant bits via Canvas and runs a chi-squared test plus an LSB-balance check. 3. Read the likelihood: A high chi-squared embedding score or a near-perfect 50/50 LSB balance suggests hidden data; a low score suggests a clean image. FAQ: Q: Does this extract the hidden message? A: No. It is a detector, not an extractor. It uses statistics to estimate whether sequential LSB embedding is likely present and reports a likelihood, because extraction needs the embedding scheme, ordering and any password. Q: Why only PNG and BMP, not JPEG? A: LSB steganography hides data in the lowest bit of pixel values, and JPEG's lossy compression rewrites those values, destroying the payload. Only lossless formats like PNG and BMP preserve LSBs, so detection is meaningful there. Q: How does the chi-squared test work? A: Natural images have uneven counts within each pair of values that differ only in the last bit (e.g. 100 vs 101). Sequential LSB embedding flattens those pairs toward equality. The chi-squared statistic measures that flattening across all value pairs; a large value indicates likely embedding. Q: Can it give false positives? A: Yes. Heavily processed, dithered or synthetic images can naturally have balanced LSBs and may score high, while data hidden in only part of an image may score low overall. Treat the result as a signal to investigate, not proof. Q: Is my image uploaded? A: No. The image is decoded into a Canvas in your browser and all pixel math runs in JavaScript locally. Nothing is sent to a server, which matters for sensitive forensic material. #### Screen Resolution & Aspect Ratio Checker URL: https://geratools.com/screen-resolution-aspect-checker Free screen resolution checker — detects your display resolution and reports the aspect ratio, megapixels and matching standard (16:9, 16:10, 21:9 and more). Runs entirely in your browser. How to use: 1. See your detected resolution: The checker reads your screen's physical pixel width and height automatically on load. 2. Or enter any resolution: Type a custom width and height to identify the aspect ratio of any display or image. 3. Read the ratio: See the reduced aspect ratio, its named standard, decimal value and total megapixels. FAQ: Q: What is my screen resolution? A: The checker reads it directly from your browser — screen width and height multiplied by your device pixel ratio to give physical pixels. It then reduces those numbers to an aspect ratio and identifies the matching standard. Q: How is the aspect ratio worked out? A: The width and height are divided by their greatest common divisor to reduce the ratio to lowest terms. So 1920×1080 reduces to 16:9 and 2560×1600 reduces to 16:10. Q: What aspect ratio is my monitor? A: Most modern monitors and TVs are 16:9 (widescreen). Many laptops are 16:10 or 3:2, ultrawide monitors are 21:9, and older displays are 4:3. The tool names the standard for any resolution you enter. Q: Is any screen data sent anywhere? A: No. The screen resolution checker runs entirely in your browser. Your display details are read and processed locally and never uploaded. #### Brightness & Contrast Adjuster URL: https://geratools.com/image-brightness-contrast Free brightness and contrast image editor. Brighten, darken, and adjust the contrast of any photo with live sliders and an instant preview. Runs entirely in your browser — no upload. How to use: 1. Choose an image: Drop a photo onto the box or click to select one from your device. 2. Adjust the sliders: Drag the brightness and contrast sliders; the preview updates instantly. 3. Download the result: Save the adjusted image as a PNG. FAQ: Q: How does the contrast adjustment work? A: It scales each colour channel around the mid-grey value of 128 using the standard contrast factor, so positive values push lights and darks apart and negative values bring them together. Q: What range do the sliders cover? A: Both brightness and contrast range from -100 to +100, where 0 leaves the image unchanged. Brightness adds or subtracts light; contrast widens or narrows the tonal spread. Q: What is the contrast formula? A: It uses the standard contrast factor F = (259 × (c + 255)) / (255 × (259 − c)), where c is the contrast value mapped to ±255. Each channel becomes F × (value + brightness − 128) + 128, then is clamped to 0-255. Q: Does it change brightness and contrast at the same time? A: Yes. Both adjustments are applied in a single pass per pixel — brightness is added as an offset and contrast scales the result around the mid-grey value of 128, so you can balance the two together. Q: Will this reduce image quality? A: The maths runs on the full-resolution pixels and exports a lossless PNG, so there is no extra compression. Extreme settings can clip highlights or shadows to pure white or black, which loses detail in those areas. Q: Is my photo uploaded? A: No. All adjustments are computed in your browser via the canvas API, so the image never leaves your device. #### Screen Resolution Checker URL: https://geratools.com/screen-resolution-checker Free screen resolution checker — instantly shows your display resolution, physical pixels, device pixel ratio, aspect ratio and colour depth. Detected locally in your browser, nothing uploaded. How to use: 1. Open the tool: The checker reads your display details from the browser as soon as the page loads. 2. Compare CSS and physical pixels: See both the CSS resolution and the true device-pixel resolution after the device pixel ratio is applied. 3. Resize to watch it update: Resize or move the window between monitors and the viewport and ratio values refresh live. FAQ: Q: Why is my physical resolution higher than the reported resolution? A: High-DPI (Retina) screens use a device pixel ratio above 1, so the physical pixel count is the CSS resolution multiplied by that ratio. A 2560×1440 screen at 2× reports 5120×2880 physical pixels. Q: Is the screen resolution different from the browser viewport? A: Yes — screen resolution is the whole display, while the viewport is just the area inside the browser window after toolbars and scrollbars. Both are shown here. Q: Is any of this sent to a server? A: No — all values come from your own browser via the standard screen API and stay on your device. Q: What is device pixel ratio? A: It is how many physical pixels make up one CSS pixel. A ratio of 1 means one-to-one, while 2 (common on Retina and high-DPI screens) means each CSS pixel is rendered as a 2×2 block of physical pixels for sharper text. Q: How do I find my aspect ratio? A: It is the screen width divided by the height reduced to whole numbers. 1920 × 1080 is 16:9, 2560 × 1600 is 16:10, and the tool calculates it for you automatically. Q: Why does the available area differ from the full resolution? A: The available area excludes space reserved by the operating system, such as the Windows taskbar or the macOS menu bar and Dock, so it is the usable area a maximised window can occupy. #### Image Dimension Scaler URL: https://geratools.com/image-dimension-scaler Free image dimension scaler — resize width and height by a percentage or to a target width or height while keeping the exact aspect ratio. Pure pixel maths in your browser, no upload. How to use: 1. Enter original dimensions: Type the source image width and height in pixels. 2. Choose how to scale: Scale by a percentage, or set a target width or target height to resize toward. 3. Read the new size: The matching dimensions are computed instantly so the aspect ratio is preserved exactly. FAQ: Q: Does this resize the actual image file? A: No — it calculates the target pixel dimensions only. It is a planning tool for figuring out the right width and height before you export from an editor or CDN. Q: How does it keep the aspect ratio? A: When you set a target width it computes height = width ÷ (original width ÷ original height), and the reverse when you set a target height, so the image never stretches. Q: Why are the results rounded? A: Pixel dimensions must be whole numbers, so each computed width and height is rounded to the nearest integer. This can shift the final aspect ratio by a fraction of a pixel, which is invisible in practice. Q: Can I scale up as well as down? A: Yes. A percentage above 100 (for example 200) doubles the dimensions, and a target larger than the original enlarges the image. Remember that enlarging beyond the source resolution will look soft when actually rendered. Q: What is the difference between scaling by width and by height? A: Set a target width and the tool solves the height from the original ratio; set a target height and it solves the width. Both keep the image proportional — you just choose which side to fix. Q: Is anything uploaded? A: No — it is pure arithmetic that runs entirely in your browser. #### Document Scanner URL: https://geratools.com/document-scanner Free online document scanner. Turn phone photos of paper documents into clean, high-contrast scanned pages and export a multi-page PDF — magic colour, black & white, and greyscale modes. 100% in your browser, nothing is uploaded. How to use: 1. Add your document photos: Drop one or more photos of your pages, or tap Choose photos. Each photo becomes a page. 2. Pick a scan mode: Choose Magic colour to whiten the page, Black & white for a crisp 1-bit scan, or Greyscale, then fine-tune brightness and contrast. 3. Order the pages and export: Drag the page thumbnails into order, pick A4 or US Letter, and download a multi-page PDF. FAQ: Q: Are my documents uploaded anywhere? A: No. Every step — decoding the photo, the image processing, and building the PDF — happens entirely inside your browser using JavaScript and the Canvas API. No file ever leaves your device, which is why this works offline once the page has loaded and is safe for sensitive paperwork like contracts, IDs and bank statements. Q: What is the difference between Magic colour and Black & white? A: Magic colour estimates the page background per region and divides it out, which flattens uneven lighting and shadows so the paper turns bright white while ink and colour stamps stay readable. Black & white converts each pixel to pure black or white using an adaptive threshold — the smallest possible file, ideal for plain text documents you want to print or fax. Q: How does it remove shadows and uneven lighting? A: The scanner samples the brightest luminance across a coarse 24×24 grid to estimate where the white paper is, then smoothly upscales that map and normalises every pixel against its local background. Areas that were dimmed by a shadow get lifted back toward white, so a photo taken in imperfect light still looks like a flat-bed scan. Q: Can I scan a multi-page document? A: Yes. Add as many photos as you like — each becomes a page. You can reorder pages by dragging the thumbnails, move them up or down, delete bad shots, and then export everything as a single multi-page PDF in the right order. Q: What file format should my photos be? A: JPG and PNG work everywhere. Photos straight from a phone are usually JPG and decode instantly. If your phone saves HEIC, export or share the photo as JPG first (most phones do this automatically when you share), then drop it in here. Q: How do I get the cleanest result? A: Fill the camera frame with the page, shoot in even light without harsh shadows, and keep the paper flat. Then use Magic colour or Black & white, nudge contrast up, and leave Sharpen text on. The threshold slider in Black & white mode lets you control exactly how aggressively faint marks are kept or dropped. Q: Why are black & white pages exported losslessly but colour pages as JPEG? A: A pure black-and-white page compresses perfectly as PNG with no artefacts and a tiny file size. Colour and greyscale pages contain smooth gradients that PNG cannot compress well, so they are saved as JPEG at your chosen quality to keep the PDF small while still looking sharp. ## Everyday & Quick-Help Apps > Handy little browser apps — generators, trackers, planners, timers and references that solve an everyday problem in seconds. Free, private, and instant, with nothing to install. ### Trackers & Planners #### Keyboard Tester URL: https://geratools.com/keyboard-tester Free online keyboard tester. Press keys and watch each one light up on an on-screen layout to find a dead, stuck or double-typing key. Shows event.code and keyCode. Runs entirely in your browser — nothing is recorded or uploaded. How to use: 1. Click the keyboard panel: Click inside the on-screen keyboard area so it has focus and can receive your key presses. 2. Press each key: Press keys one at a time. Each key turns green while held and stays outlined once it has registered at least once. 3. Look for keys that never light up: Any key that stays unlit no matter how hard you press it is likely dead. A key that stays green after release may be stuck. FAQ: Q: How does an online keyboard tester work? A: It listens for the browser keydown and keyup events your keyboard sends. When a key registers, its box lights up and its event.code, key value and keyCode are shown. If a key never lights up, the browser never received a signal for it — a sign the switch is dead. Q: Why does a key not show up when I press it? A: Either the physical key or its switch has failed, or the key is intercepted by the operating system before the browser sees it (some media, brightness and Fn keys behave this way). Standard letter, number and modifier keys should always register. Q: Can this detect a stuck or chattering key? A: Yes. A stuck key stays highlighted green after you let go. A chattering key that double-types will fire repeated keydown events for a single press, which you can see by watching the last-key readout change rapidly. Q: Is my typing sent anywhere? A: No. Every key event is handled locally in your browser. Nothing you type is logged, stored or uploaded, so it is safe to use even while a password field is not involved. Q: Does it test the numeric keypad and media keys? A: The visual layout covers the main typing block, function row and arrow keys. Any other key you press — including numpad keys — is still counted in the registered-keys total even if it is not drawn on the map. #### Scoreboard & Score Keeper URL: https://geratools.com/scoreboard Free online scoreboard and score keeper. Add players, tap plus or minus to adjust points, rename anyone inline, and the leader is highlighted automatically. Perfect for board games, cards and sports. Runs in your browser. How to use: 1. Add your players: Type a name and press Add for each player. You can rename anyone later by editing their name field. 2. Set the points per tap: Choose how many points each tap is worth — 1, 2, 3, 5 or 10 — to match your game scoring. 3. Keep score: Tap plus or minus next to a player to adjust their total. The current leader is highlighted automatically. FAQ: Q: How many players can I track? A: As many as you like. Add a new player at any time, and remove anyone with the cross button. The leader is always highlighted based on the current scores. Q: Can I change how many points each tap adds? A: Yes. Pick a points-per-tap value of 1, 2, 3, 5 or 10 so a single tap matches your game scoring, whether that is single points or larger increments. Q: Are scores saved if I close the tab? A: No. Scores live only in the open tab and reset when you reload or close it, which keeps the tool private and free of any stored data. Q: Can scores go negative? A: Yes. The minus button can take a player below zero, which is useful for games with penalties or forfeits. #### Keyboard Shortcuts Reference URL: https://geratools.com/keyboard-shortcuts-reference A searchable keyboard shortcuts reference for macOS and Windows covering editing, navigation, files, browser tabs and screenshots. Switch OS to see the right keys. Runs entirely in your browser, nothing is uploaded. How to use: 1. Pick your operating system: Choose macOS or Windows so every shortcut shows the correct keys for your machine. 2. Search for an action: Type what you want to do, like copy or screenshot, to filter the whole list instantly. 3. Read the keys: Each row shows the action and the exact key combination for the selected operating system. FAQ: Q: How do I take a screenshot of part of the screen? A: On macOS press Command Shift 4 then drag to select an area. On Windows press Windows Shift S to open the snipping toolbar and drag the region you want. Q: How do I reopen a tab I just closed? A: Press Command Shift T on macOS or Ctrl Shift T on Windows in most browsers. You can press it repeatedly to reopen tabs in the order they were closed. Q: Is anything I search uploaded? A: No. The whole reference and its search run in your browser, so nothing you type is ever sent anywhere. Q: How do I copy and paste with the keyboard? A: Press Command C to copy and Command V to paste on macOS, or Ctrl C and Ctrl V on Windows. To paste without formatting, use Command Shift V on macOS or Ctrl Shift V on Windows. Q: How do I switch between open apps quickly? A: Hold Command and press Tab on macOS, or hold Alt and press Tab on Windows. Keep the first key held and tap Tab repeatedly to cycle through open applications. Q: What is the Mac equivalent of Ctrl on Windows? A: For most shortcuts the Mac Command key (⌘) replaces the Windows Ctrl key — so Ctrl C becomes Command C. The Mac also has its own Control key, used mainly for special shortcuts like right-click and screen lock. Q: How do I find text on a page? A: Press Command F on macOS or Ctrl F on Windows to open the find bar in documents and browsers, then type the text you are looking for. #### Initiative Tracker URL: https://geratools.com/initiative-tracker Free initiative tracker for D&D and tabletop RPGs — add combatants, auto-sort by initiative, step through turns and track HP. Runs entirely in your browser, nothing is uploaded. How to use: 1. Add combatants: Enter each creature's name, initiative roll and optional HP, then press Add. The list auto-sorts highest initiative first. 2. Run the encounter: Use Next turn to advance through the order; the round counter increments automatically when it wraps back to the top. 3. Track damage: Use the plus and minus buttons next to each combatant's HP to apply damage or healing during the fight. FAQ: Q: Does it sort combatants automatically? A: Yes. Whenever you add a combatant the list re-sorts by initiative, highest first, so the turn order is always correct. Q: Can I track hit points? A: Yes. HP is optional per combatant. When set, plus and minus buttons let you apply damage or healing, and the value turns red at zero or below. Q: How are ties in initiative handled? A: Combatants with the same initiative keep the order in which they were added, so you can break ties manually by adding the combatant who should go first slightly earlier or by nudging their initiative by a fraction. Q: Does the round counter advance automatically? A: Yes. When Next turn wraps from the last combatant back to the top of the order, the round counter increments by one, so you always know which round you are in. Q: What happens when a combatant hits zero HP? A: The HP value turns red at zero or below to flag a downed or dead creature. You can keep it in the list for tracking or simply stop advancing its turn. Q: Is the encounter saved anywhere? A: No. The tracker lives only in your browser tab for the session — nothing is uploaded or stored on a server. Reloading the page clears it. #### Habit Tracker URL: https://geratools.com/habit-tracker A free, private habit tracker with weekly and monthly grids, current and longest streaks, and CSV/JSON export. Add habits, tick off days, and watch your streak grow. Runs entirely in your browser — nothing is uploaded. How to use: 1. Add the habits you want to build: Type a habit name like 'Exercise' or 'Read' and press Add. Each habit gets its own colour and row in the grid. 2. Tick off each day you complete it: Click a cell in the weekly or monthly grid to mark that day done. Click again to undo. Future days are locked. 3. Watch your streaks and export: Each row shows your current streak, longest streak and completion for the visible range. Export the grid as CSV or your full history as JSON anytime. FAQ: Q: How is the current streak calculated? A: The current streak counts consecutive completed days ending at today. If today is not ticked yet, it counts back from yesterday so an unfinished day does not break the run. The longest streak is the best consecutive run anywhere in your history. Q: Where is my data stored? A: Everything is saved in your browser using localStorage. No account, no sign-up, and nothing is ever sent to a server. Clearing your browser data or using private mode will remove it, so export a JSON backup if you want it to last. Q: What is the difference between the weekly and monthly view? A: The weekly view shows seven larger cells (Monday to Sunday) and is best for daily check-ins. The monthly view shows every day of the month in a compact grid so you can spot patterns and gaps across the whole month at a glance. Q: Can I move my data to another device or browser? A: Yes. Use Export JSON to download your full history, then open the tracker on the other device and use Import JSON to load it. The import also repairs basic shape issues and ignores malformed dates. Q: Why can I not tick future days? A: Future cells are locked on purpose. A habit tracker only works if it reflects what you actually did, so you can only mark today or any past day. This keeps your streaks honest. Q: Does the CSV export work in Excel or Google Sheets? A: Yes. The CSV has one column per visible day with a 1 for done and 0 for missed, plus a habit-name column. Open it directly in Excel, Numbers or Google Sheets to chart your consistency or build your own reports. #### Name Numerology Calculator URL: https://geratools.com/name-numerology Free name numerology calculator: get your Expression (Destiny), Soul Urge and Personality numbers using the Pythagorean system. Runs entirely in your browser — nothing is uploaded. How to use: 1. Type your name: Enter the name you want to analyse — your full birth name is traditional, but any name works. 2. Read your numbers: The Expression, Soul Urge and Personality numbers appear instantly with a short meaning for each. 3. Explore the meanings: Compare the numbers and the brief descriptions to reflect on the traits each one represents. FAQ: Q: How are the numbers calculated? A: Each letter is mapped to a digit 1-9 using the Pythagorean system, the digits are summed and then reduced to a single digit. Vowels give the Soul Urge number, consonants give the Personality number, and all letters together give the Expression number. Master numbers 11, 22 and 33 are kept. Q: What is the difference between the three numbers? A: The Expression (Destiny) number uses every letter and describes your overall potential and life direction. The Soul Urge number uses only the vowels and reflects inner desires and motivation. The Personality number uses only the consonants and reflects the outward impression others form of you. Q: What is a master number? A: When the letter total reduces to 11, 22 or 33 it is treated as a master number rather than reduced further, because numerology considers these especially significant. The calculator stops reduction at these values instead of collapsing them to 2, 4 or 6. Q: Which name should I use — birth name or nickname? A: Traditional numerology uses your full birth name as it appears on your birth certificate, because that is considered the original blueprint. You can also test a nickname or married name to compare how a chosen name shifts the numbers. Q: How are the letters mapped to numbers? A: A through I map to 1-9, J through R repeat 1-9, and S through Z map to 1-8. So A, J and S all equal 1; B, K and T all equal 2, and so on. Spaces, punctuation and digits are ignored. Q: Does spelling or capitalisation matter? A: Capitalisation does not matter — letters are read case-insensitively. Spelling does matter, because each different letter changes the totals, so two spellings of the same-sounding name can give different numbers. Q: Is name numerology scientifically proven? A: No. Numerology is a belief system and a form of entertainment, not a science. Use the results for reflection and fun rather than for important decisions. Q: Is my name sent anywhere? A: No. The whole calculation happens in your browser and nothing is uploaded or stored. #### Reading List Tracker URL: https://geratools.com/reading-list-tracker A free reading list tracker that runs in your browser. Add books, set them as want-to-read, reading, finished or DNF, rate with stars, log page progress and notes, filter and search, then export to CSV or back up to JSON. Nothing is uploaded. How to use: 1. Add a book: Type the title (and optionally author, genre and page count), choose a shelf, and press Add. 2. Track progress and rate it: Open a book to move it between shelves, log the current page, and give it a 1-5 star rating. 3. Export or back up: Use Export CSV for a spreadsheet of every book, or Backup JSON to save and later restore your whole list. FAQ: Q: Where is my reading list stored? A: Entirely in your own browser using localStorage. Nothing is sent to a server, so your list stays private to this device and survives page refreshes and browser restarts. Q: What do the four shelves mean? A: Want to read is your to-be-read pile, Reading is in progress, Finished is completed, and Did not finish (DNF) is for books you stopped without finishing. Click any shelf card at the top to filter to just those books. Q: How does the page-progress bar work? A: Add a total page count to a book, then log your current page. The tracker shows the percentage complete. Marking a book Finished automatically sets it to 100 percent and records the finish date. Q: Can I move my list to another device? A: Yes. Use Backup JSON to download a file, copy it to the other device or browser, and use Restore JSON to load it. CSV export is also available if you prefer a spreadsheet. Q: How are the star ratings used? A: Each book can hold a 1-5 star rating that you set by clicking the stars. The summary line shows your average rating across finished, rated books, so you can see how you tend to score what you read. Q: Will I lose my books if I clear my browser data? A: Clearing site data or using private browsing will remove the stored list, because it lives only in this browser. Use Backup JSON regularly if you want a permanent copy you control. #### Eisenhower Matrix URL: https://geratools.com/eisenhower-matrix Free Eisenhower Matrix tool — add tasks, flag them urgent and important, and instantly see whether to do, schedule, delegate or delete each one. Runs entirely in your browser; nothing is uploaded. How to use: 1. Add a task: Type a task and tick whether it is urgent and whether it is important. 2. Watch it sort: The task drops into one of four quadrants automatically based on your flags. 3. Act on each quadrant: Do now, schedule, delegate or delete each task as the matrix suggests. FAQ: Q: What are the four Eisenhower quadrants? A: Urgent and important means do it now; important but not urgent means schedule it; urgent but not important means delegate it; neither means delete it. Q: Where does my list go? A: Everything stays in your browser tab and is never sent anywhere. Closing or reloading the page clears the list. Q: Can I reclassify a task? A: Remove the task and re-add it with different urgent or important flags to move it to another quadrant. Q: What is the difference between urgent and important? A: Urgent means it demands attention now — a deadline, a ringing phone. Important means it contributes to your long-term goals. Many urgent things are not important, which is exactly the trap the matrix is built to expose. Q: Where did the Eisenhower Matrix come from? A: It is named after US President Dwight D. Eisenhower, who said "What is important is seldom urgent and what is urgent is seldom important." Author Stephen Covey popularised it as a 2x2 grid in The 7 Habits of Highly Effective People. Q: Which quadrant should I focus on? A: The "Schedule" quadrant — important but not urgent — is where high-value work lives: planning, learning, prevention and relationships. Spending more time here shrinks the stressful "Do now" pile over time. Q: Why delegate the urgent-but-not-important tasks? A: These tasks have to happen soon but do not need your specific skills, so they are the best candidates to hand to someone else. That frees your attention for the important quadrants only you can handle. #### Time Blocking Planner URL: https://geratools.com/time-blocking-planner Free time blocking planner — add focused blocks by start time and duration, see end times calculated automatically, and track your total scheduled hours. Runs entirely in your browser; nothing is uploaded. How to use: 1. Set a start time and duration: Pick when a block begins and how many minutes it should run. 2. Label and add the block: Name the block and add it; the next start time is pre-filled to follow on. 3. Review your day: See every block with its end time and your total scheduled hours. FAQ: Q: How is each block end time calculated? A: The planner adds the duration in minutes to the start time. After adding a block, the next start time auto-fills to that end time so blocks chain together. Q: Does it save my plan? A: No. The schedule lives only in your browser tab and clears when you reload or close the page. Nothing is sent to a server. Q: Can blocks overlap? A: Yes — you can enter any start time you like, so overlaps are possible if you set them. Blocks are sorted by start time for easy reading. Q: What is time blocking? A: Time blocking is assigning each part of your day to a specific task in advance, instead of working from an open to-do list. It reduces context switching and makes your day's capacity visible. Q: What happens if a block crosses midnight? A: Clock times wrap within a 24-hour day, so a block starting at 23:30 for 60 minutes ends at 00:30. The planner shows the wrapped end time. Q: Can I remove or change a block? A: Yes. Each block can be removed, and you can add new ones at any start time. The list re-sorts by start time so your day stays in order. Q: How is total scheduled time worked out? A: It sums the durations of all your blocks and shows the total in hours and minutes, so you can quickly tell whether your plan fits the time you have. #### Weekly Goal Tracker URL: https://geratools.com/weekly-goal-tracker Free weekly goal tracker — add goals with a weekly target, tick off progress, and watch progress bars and an overall completion percentage update live. Runs entirely in your browser; nothing is uploaded. How to use: 1. Add a goal and target: Name a weekly goal and set how many times you want to hit it this week. 2. Log progress: Use the plus and minus buttons to record each time you complete the goal. 3. Track overall progress: Each goal shows a progress bar, and an overall percentage rolls up across all goals. FAQ: Q: How is overall progress calculated? A: It totals the completed counts across all goals and divides by the sum of all targets, giving a single weekly completion percentage. So two goals at 3/5 and 1/2 give (3 + 1) ÷ (5 + 2) = 57 percent overall. Q: How do I record progress? A: Each goal has plus and minus buttons. Tap plus when you complete it and minus to undo a mistake. The bar and percentage update instantly. Q: Does it remember my goals next week? A: No. The tracker keeps goals only in your current browser tab; reloading or closing the page clears them so you start each session fresh. Q: Can progress go above the target? A: No — progress is capped at the target for each goal, so a goal can show at most 100 percent complete. Extra taps beyond the target are ignored. Q: Can the count go below zero? A: No. The minus button stops at zero, so a goal never shows negative progress. Q: How many goals can I track? A: As many as you like. Each new goal is added to the list with its own target and progress bar, and all of them feed the overall percentage. Q: Is anything uploaded or shared? A: No. Everything stays in your browser tab and nothing is sent to a server, so your goals are completely private. #### Focus Session Logger URL: https://geratools.com/focus-session-logger Free focus session logger — record what you worked on, how many minutes, and a 1-to-5 focus quality rating, then see total focused time and your average focus score. Runs entirely in your browser; nothing is uploaded. How to use: 1. Describe the session: Note what you focused on and how many minutes it lasted. 2. Rate your focus: Pick a focus quality from 1 to 5 to capture how deep the session felt. 3. Review your totals: See total focused time and your average focus rating across all logged sessions. FAQ: Q: What does the focus rating mean? A: It is a self-assessed 1-to-5 score for how deep and undistracted the session felt, shown as stars and rolled up into an average across all sessions. Q: Is my log saved or shared? A: No. Sessions stay in your current browser tab only and are cleared when you reload or close the page. Nothing is sent to a server. Q: How is total focused time worked out? A: It simply adds up the minutes from every logged session and shows the sum in hours and minutes. Q: Does this work as a Pomodoro tracker? A: Yes. Log each 25-minute Pomodoro (or any block) as a session with its duration and a focus rating, and the running totals show how many focused minutes you have accumulated across them. Q: Why log a focus rating instead of just time? A: Time alone hides quality — two 60-minute blocks can differ enormously in how much you actually got done. The 1-to-5 rating captures depth, so the average reveals which tasks or times of day produce your best concentration. Q: Will I lose my sessions if I refresh? A: Yes. The log is kept only in the current tab and clears on reload or close, by design, to stay fully private. Note down anything you want to keep before leaving the page. #### Pros and Cons List Maker URL: https://geratools.com/pros-cons-list Free weighted pros and cons list maker. Score each point by importance, compare multiple options side by side, see the net score and verdict, then export to Markdown or CSV. Runs entirely in your browser. How to use: 1. Name your decision and options: Type the question at the top, then add one card per option you are weighing. 2. List pros and cons with weights: Add each point and set its importance from 1 (trivial) to 5 (critical) so big factors count more than small ones. 3. Read the net score and verdict: Each card shows pros minus cons, a coloured balance bar and a verdict. The leading option is highlighted at the top. 4. Export your decision: Download a Markdown or CSV summary, or copy the Markdown to paste into notes, email or a document. FAQ: Q: How is the net score calculated? A: Each pro and con carries a weight from 1 to 5. The tool adds the weights of all your pros, adds the weights of all your cons, and subtracts the second from the first. A positive net score means the pros outweigh the cons; a negative score means the reverse. Q: Why use weights instead of just counting points? A: A plain count treats every factor as equal, which is rarely true. One critical drawback can outweigh five trivial benefits. Weighting from 1 to 5 lets a single major factor dominate the result, so the verdict reflects what actually matters to you rather than how many bullet points you happened to write. Q: What does the verdict label mean? A: The verdict compares the net score against the total weight in play. Strong go, leans yes, too close to call, leans no and strong no map to how lopsided the balance is, so a small lead on a huge list reads as close while a big lead on a focused list reads as decisive. Q: Can I compare more than two options? A: Yes. Add as many option cards as you like and the tool ranks them by net score, highlights the leader at the top and includes every option in the exported summary, turning it into a lightweight weighted decision matrix. Q: Is my decision data saved or uploaded anywhere? A: Nothing leaves your device. The whole board is stored only in your browser local storage, so it survives a refresh but is never sent to any server. Use Reset to clear it. Q: What formats can I export to? A: You can download a formatted Markdown file, a CSV file with one row per point, or copy the Markdown to your clipboard. Markdown pastes cleanly into Notion, GitHub, email and most note apps, while CSV opens in any spreadsheet. ### Timers #### Online Timer, Stopwatch & Pomodoro URL: https://geratools.com/timer Free online timer, stopwatch and Pomodoro timer. Set a countdown, track elapsed time, or run 25/5 focus cycles — all in your browser, no signup. How to use: 1. Pick a mode: Switch between Timer, Stopwatch and Pomodoro. 2. Set and start: For the timer, enter minutes and seconds, then press Start. 3. Get notified: A sound plays when a countdown finishes. Pomodoro auto-switches between focus and break. FAQ: Q: Does the timer keep running if I switch tabs? A: Yes. It tracks real elapsed time, so leaving the tab open in the background still works. Q: What is the Pomodoro technique? A: It alternates 25 minutes of focused work with 5-minute breaks. This tool runs those cycles automatically and counts how many you complete. Q: Will it make a sound when the timer ends? A: Yes. A short beep is generated with the Web Audio API when a countdown reaches zero, and at each Pomodoro transition — no audio file is downloaded. Q: Do I need an account or to install anything? A: No. It runs entirely in your browser. There is no signup, no install, and nothing is sent to a server. Q: What is the difference between the timer and the stopwatch? A: The timer counts down from a time you set to zero; the stopwatch counts up from zero to measure how long something takes. Q: How long are the Pomodoro focus and break periods? A: The classic 25 minutes of focus followed by a 5-minute break. The tool switches between them automatically and tallies completed focus cycles. Q: Is the elapsed time accurate? A: Yes. It measures real wall-clock time rather than counting ticks, so it stays accurate even if the tab is throttled in the background. #### Tabata Timer URL: https://geratools.com/tabata-timer Free online Tabata timer. Run the classic 20-seconds-on, 10-seconds-off, 8-round protocol with audio cues, or adjust work, rest and rounds for any HIIT workout. Runs entirely in your browser — no app, no signup. How to use: 1. Set your intervals: Leave the defaults for a classic Tabata (20s work, 10s rest, 8 rounds) or change the work, rest and round fields for any HIIT pattern. 2. Press Start: A short get-ready countdown plays, then the timer cycles work and rest periods with a tone at every change. 3. Follow the cues: The panel turns green for work and amber for rest, shows the round number, and beeps when each phase switches. FAQ: Q: What is the Tabata protocol? A: Tabata is a high-intensity interval format of 20 seconds of all-out work followed by 10 seconds of rest, repeated 8 times — about 4 minutes in total. It comes from research by Dr Izumi Tabata. Q: Can I use it for other HIIT workouts? A: Yes. The work, rest and round fields are fully adjustable, so you can set up EMOM, circuit or custom interval workouts as well as classic Tabata. Q: Why do I hear different tones? A: A higher tone marks the start of a work interval and a lower tone marks rest, so you can keep your eyes off the screen and still know which phase you are in. Q: Does the timer keep running if I switch tabs? A: Keep this tab open and unmuted for reliable audio cues. The countdown uses your browser clock and audio, so a muted or backgrounded tab may miss the tones. #### Plank Timer URL: https://geratools.com/plank-timer Free online plank timer. Count up through your plank hold with one-tap target presets (30s to 5min), a progress bar, and a beep when you hit the goal. Tracks your best hold. Runs entirely in your browser. How to use: 1. Pick a target: Choose a target hold from 30 seconds up to 5 minutes, or select No target to simply count up. 2. Start the hold: Get into your plank, press Start, and the timer counts up while a progress bar tracks how close you are to the goal. 3. Hold past the beep: When you reach your target the timer beeps and turns green. Keep going to beat it — the tool records your best hold. FAQ: Q: How long should I hold a plank? A: Many programmes start around 20 to 30 seconds and build up gradually, adding a little time each week. Holding a strong, well-aligned plank for a shorter time is better than sagging through a longer one. Q: Does the timer count up or down? A: It counts up, so you can push past your target if you have more in the tank. The beep marks when you reach your chosen goal, but the clock keeps running. Q: Does it remember my best time? A: Yes, for the current session. Your best hold is shown at the bottom and updates whenever you beat it, until you reload the page. Q: Can I pause mid-hold? A: Yes. Press Pause to stop the clock and Resume to continue from where you left off, which is useful if you need to reset your form. #### Pomodoro Timer URL: https://geratools.com/pomodoro-timer Free Pomodoro timer with customizable focus and break lengths, automatic long breaks every four sessions, and a completed-session counter. Runs entirely in your browser — nothing is uploaded. How to use: 1. Set your intervals: Adjust the focus, short break and long break lengths in minutes, or keep the classic 25 / 5 / 15 defaults. 2. Start the session: Press Start to begin a focus block. A tone plays when the block ends and the timer switches to a break automatically. 3. Track your progress: Every four focus sessions trigger a long break, and the completed-session counter shows how much focused work you have done. FAQ: Q: What is the Pomodoro technique? A: It is a time-management method that alternates 25-minute focus blocks with 5-minute breaks, taking a longer break after every fourth block. This timer runs those cycles for you and counts the sessions you finish. Q: Can I change the focus and break lengths? A: Yes. Set any number of minutes for the focus block, short break and long break. Changes apply to the current phase when the timer is paused. Q: What are the default intervals? A: The classic 25 / 5 / 15 setup — 25-minute focus blocks, 5-minute short breaks, and a 15-minute long break after every fourth focus session. You can override all three. Q: When does the long break happen? A: After every fourth completed focus session the timer automatically schedules the long break instead of a short one, then the four-session cycle starts again. Q: Will it alert me when a block ends? A: Yes. A tone plays via the Web Audio API when each focus or break block finishes, and the timer switches to the next phase automatically so you do not have to watch the clock. Q: Why use the Pomodoro technique? A: Short, timed focus blocks make large tasks feel manageable, reduce procrastination, and build in regular rest so you sustain concentration over a longer day. Q: Is anything sent to a server? A: No. The timer runs entirely in your browser using JavaScript and the Web Audio API. No timings, settings or session counts are ever uploaded. #### Countdown to Date URL: https://geratools.com/countdown-to-date Free countdown timer to any future date and time, showing days, hours, minutes and seconds remaining and counting up once the date has passed. Runs entirely in your browser — nothing is uploaded. How to use: 1. Pick the target: Choose the future date and time you want to count down to using the date-and-time picker. 2. Watch it count down: The timer instantly shows the days, hours, minutes and seconds remaining and updates every second. 3. See elapsed time too: Once the target moment passes, the display switches to show how long ago it occurred. FAQ: Q: What can I count down to? A: Any date and time you choose — a launch, a birthday, an exam, a holiday or a deadline. The timer updates live every second using your device clock. Q: What happens after the date arrives? A: The countdown reaches zero and then begins counting up, showing how much time has passed since the target moment. Q: Can I count down to a specific time, not just a date? A: Yes. The picker accepts both a date and a time, so you can target a precise moment — like a product launch at 09:00 or an exam at 14:30 — down to the second. Q: Which time zone does it use? A: Your device's local time zone. The target you pick and the live clock both use local time, so the countdown matches the time where you are. Q: Is my chosen date sent anywhere? A: No. The countdown is calculated entirely in your browser from your device clock. The date you pick is never uploaded or shared. #### Box Breathing Timer URL: https://geratools.com/box-breathing-timer Free box breathing timer that guides you through inhale, hold, exhale and hold phases with an animated pacer and cycle counter. Runs entirely in your browser — nothing is uploaded. How to use: 1. Choose the phase length: Pick 3, 4, 5 or 6 seconds per phase, or keep the classic four-second box breathing rhythm. 2. Follow the pacer: Press Start and follow the on-screen prompt and the expanding and contracting square — breathe in, hold, breathe out, hold. 3. Repeat the cycle: The timer loops through all four phases continuously and counts each completed cycle so you can track your session. FAQ: Q: What is box breathing? A: Box breathing, or square breathing, is a calming technique that splits each breath into four equal phases — inhale, hold, exhale, hold — usually four seconds each. It is widely used to reduce stress and steady focus. Q: How do I do the 4-4-4-4 method? A: Breathe in for 4 seconds, hold for 4, breathe out for 4, then hold for 4, and repeat. This timer paces all four phases for you and animates a square so you can follow without counting. Q: Can I change the timing? A: Yes. Choose 3, 4, 5 or 6 seconds per phase to make the rhythm shorter or longer to suit your comfort. Four seconds is the classic box. Q: How long should a box breathing session be? A: A few minutes is common. The timer counts each completed cycle, so you can aim for a set number of cycles — for example five or ten — and stop whenever you feel calm. Q: When is box breathing useful? A: It is often used before stressful events, to wind down, or to refocus. Because it slows and regulates the breath, many people find it steadies the nervous system. Q: Does this collect any health or breathing data? A: No. The timer simply paces the phases in your browser. It does not measure, record or upload any breathing or health data — nothing leaves your device. #### HIIT Interval Timer URL: https://geratools.com/hiit-interval-timer A free HIIT interval timer for circuit training, Tabata and EMOM workouts. Configure work, rest, rounds and sets, get a big countdown with round tracker and beep cues, and export your routine. Runs entirely in your browser. How to use: 1. Set your work and rest times: Enter how many seconds each work bout lasts and how long you rest between bouts. 2. Choose rounds and sets: Pick how many rounds make up a set, how many sets to run, and an optional longer break between sets. 3. Press Start and follow the countdown: The big timer counts each phase down, beeps on every transition, and tracks your current round and set. FAQ: Q: What is a HIIT interval timer? A: A HIIT (high-intensity interval training) timer alternates short, hard work bouts with timed rest periods. You set the work seconds, rest seconds, number of rounds and number of sets, and the timer runs the whole sequence automatically with a clear countdown and audio cues so you never have to watch a clock mid-workout. Q: How do I set up a Tabata workout? A: Tabata is 20 seconds of work and 10 seconds of rest repeated for 8 rounds — four minutes total. Use the built-in Tabata preset, or set work to 20, rest to 10, rounds to 8 and sets to 1. Add a 10-second prepare phase so you have time to get into position before the first bout. Q: What is the difference between rounds and sets? A: A round is one work-then-rest cycle. A set is a group of rounds. After the last round of a set the timer can insert a longer set break before the next set begins. Use sets when you want to repeat a circuit several times with a proper recovery in between, such as three sets of six 30-second exercises. Q: Will the timer keep my screen awake? A: On browsers that support the Screen Wake Lock API the timer requests a lock while it is running, so your phone or tablet screen stays on through the workout. If the browser does not support it the timer still runs normally; just disable auto-lock in your device settings as a fallback. Q: Can I run EMOM workouts with this timer? A: Yes. EMOM (every minute on the minute) is just a 60-second work bout with no rest, repeated for the number of minutes you want. Load the EMOM preset or set work to 60, rest to 0 and rounds to the minute count. You will hear a beep at the top of every minute. Q: Is anything sent to a server? A: No. The timer, the audio beeps and your saved routine all run entirely in your browser. Your routine is stored in your browser's local storage, and the export and import buttons move it as a plain JSON file on your own device. Nothing is uploaded. ### Generators & Pickers #### QR Code Generator URL: https://geratools.com/qr-code-generator Free QR code generator. Make QR codes for links, text, WiFi and contacts with custom colors and size. Download as PNG or SVG — generated in your browser, no signup. How to use: 1. Enter your content: Type a URL, text, or any data you want encoded. 2. Customize: Choose size, foreground and background colors, and error-correction level. 3. Download: Save the QR code as a high-resolution PNG or a scalable SVG. FAQ: Q: Do these QR codes expire? A: No. The QR code encodes your content directly, so it works forever and isn't tied to any server or tracking redirect. "Dynamic" QR services that promise editable links route through a redirect that can break or start charging — this tool does not. Q: Can I download a vector QR code? A: Yes. Download as SVG for print or large displays where it scales without pixelation, or PNG for everyday on-screen use. Q: Is my data sent anywhere? A: No. The QR code is generated entirely in your browser. Q: What is the error-correction level and which should I choose? A: Error correction adds redundant data so the code still scans if part is damaged or covered. L recovers 7%, M 15%, Q 25%, and H 30%. Use M for general use; choose H if you plan to overlay a logo or print on a surface that may get scuffed. Q: What size should the QR code be? A: You can set 80 to 1024 pixels. For print, a rough rule is the code should be at least one tenth of the scanning distance — about 2-3 cm for phone scanning at arm's length. Keep a quiet (blank) margin around it. Q: Can I use custom colors? A: Yes, you can set the foreground and background colors. Keep strong contrast — a dark pattern on a light background scans best. Low-contrast or inverted (light on dark) codes often fail to scan. Q: What can I encode in a QR code? A: Any text works, including plain URLs, phone numbers (tel:), email, and structured strings such as WiFi credentials (WIFI:S:name;T:WPA;P:pass;;) or vCard contact data. The phone's camera interprets the format. #### Password Generator URL: https://geratools.com/password-generator Free password generator and passphrase builder. Set length, toggle uppercase, lowercase, digits and symbols, exclude ambiguous characters, and check strength — all without uploading anything. Uses crypto.getRandomValues for true randomness. How to use: 1. Choose mode: Pick "Password" for a traditional random password or "Passphrase" for a string of random words that is both strong and memorable. 2. Configure your options: In password mode, drag the length slider (6–64 characters) and toggle which character sets to include. Tick "Exclude ambiguous characters" to avoid easily confused characters like O, 0, l and 1. In passphrase mode, choose the number of words (3–8) and the separator character. 3. Generate and copy: Click Generate to create your password, review the strength meter, then hit "Copy to clipboard" to use it instantly. FAQ: Q: Is this password generator truly random? A: Yes. It uses the browser's built-in crypto.getRandomValues API — the same source used by cryptographic libraries — never the weaker Math.random(). The strength meter scores length, character-set variety, and minimum length thresholds. Q: What makes a passphrase stronger than a random password? A: A 4-word passphrase drawn from a dictionary of 256 words has 256⁴ = ~4.3 billion combinations and is much easier to type and remember than a short random string. Longer passphrases are effectively uncrackable with current hardware. Q: Are my passwords stored or sent anywhere? A: No. Everything runs entirely in your browser — no passwords are ever transmitted to a server, stored in a database, or logged anywhere. Close the tab and the password is gone. Q: How long should my password be? A: Length matters more than complexity. 12 characters is a sensible floor, 16+ is recommended for important accounts, and the slider goes up to 64. For a manager-stored password there is no downside to going long. Q: What does "exclude ambiguous characters" do? A: It removes characters that are easy to confuse when read or typed by hand — the digits 0 and 1 and the letters O, I and l. Tick it when a password may be read aloud or typed from a screen; leave it off for maximum character variety. Q: Should I use a password or a passphrase? A: Use a random password when a service allows symbols and you store it in a manager. Use a passphrase (random words joined by a separator) when you need to type or remember it — it is far easier on a phone keyboard while staying strong because of its length. Q: How does the strength meter work? A: It scores the password from Very Weak to Very Strong based on its length and how many character sets (upper, lower, digits, symbols) it draws from, with bonus points for longer lengths. It is a guide to entropy, not a guarantee against every attack. #### Binaural Beats Generator URL: https://geratools.com/binaural-beats-generator Free binaural beats generator. Play two pure tones a few hertz apart — one per ear — with adjustable carrier, beat frequency and volume, plus delta, theta, alpha, beta and gamma presets. Synthesised in your browser, nothing streamed. How to use: 1. Put on stereo headphones: The effect depends on a slightly different tone reaching each ear, so headphones are required. 2. Pick a preset or set the beat: Choose a delta, theta, alpha, beta or gamma preset, or set the beat frequency slider to any value from 1 to 40 Hz. 3. Adjust and play: Tune the carrier frequency and volume to a comfortable level, then press Play. Everything updates live while it plays. FAQ: Q: What are binaural beats? A: Binaural beats are an auditory illusion. When each ear hears a pure tone at a slightly different frequency, the brain perceives a third, slower pulse equal to the difference between them — for example 200 Hz in one ear and 210 Hz in the other produces a 10 Hz beat. Q: Why do I need headphones? A: The two tones must stay separate until they reach each ear. Over speakers they mix in the air and you hear a single wavering tone instead of a true binaural beat, so stereo headphones are essential. Q: What do the frequency presets mean? A: The presets label the classic EEG bands as a convenience: delta (about 2 Hz), theta (about 6 Hz), alpha (about 10 Hz), beta (about 20 Hz) and gamma (about 40 Hz). They set the beat frequency — the perceived pulse — not the pitch you hear. Q: Are binaural beats a medical treatment? A: No. This is an audio tool, not a medical device, and the presets are labels only. Many people find certain beat frequencies pleasant for focus, relaxation or winding down, but effects vary and it is not a substitute for medical advice. Q: Is any audio downloaded or streamed? A: No. Both tones are synthesised in real time in your browser with the Web Audio API. Nothing is streamed from or uploaded to a server, so it works even offline once the page has loaded. #### Calendar Event QR Code Generator URL: https://geratools.com/calendar-event-qr-code Free calendar event QR code generator. Encode an event title, time, location and description into a QR code that adds the event to any phone calendar. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter the event details: Add the event title, start and end times, location and an optional description. 2. Times convert automatically: Your local start and end times are converted into the standard iCalendar format. 3. Download and share: Save the QR code as PNG or SVG and add it to invitations, posters or flyers. FAQ: Q: What happens when someone scans the event QR code? A: Their phone reads the iCalendar data and offers to add the event — with title, time, location and notes — to their calendar app. Q: How are time zones handled? A: Your local start and end times are converted to UTC inside the standard iCalendar format, so the event lands at the right moment on any device. Q: Is my event data uploaded anywhere? A: No. The iCalendar event and QR code are generated entirely in your browser; nothing is sent to a server. Q: Which calendar apps support event QR codes? A: Any app that reads iCalendar (.ics) data works, including Apple Calendar, Google Calendar and Microsoft Outlook. The scanner on most modern phones recognises the format automatically. Q: Should I download the QR code as PNG or SVG? A: Use PNG for posts, slides and most print jobs. Use SVG when you need to scale the code large — for a banner or poster — without any loss of sharpness, since SVG is vector-based. Q: What is the minimum information an event QR code needs? A: A title and a start time are enough to create a usable event. End time, location and description are optional but make the calendar entry far more helpful to whoever scans it. Q: Can one QR code be scanned by many people? A: Yes. The code is static and contains the full event, so any number of people can scan the same printed or on-screen code and each add the event independently. #### Email QR Code Generator URL: https://geratools.com/email-qr-code Free email QR code generator. Encode a recipient, subject and message into a QR code that opens a ready-to-send email. Runs entirely in your browser — nothing is uploaded. How to use: 1. Enter the recipient: Type the email address the message should be sent to. 2. Add subject and message: Optionally prefill a subject line and message body so the email is ready to send. 3. Download and share: Save the QR code as PNG or SVG and add it to flyers, business cards or support pages. FAQ: Q: What happens when someone scans an email QR code? A: Their phone opens the default mail app with the recipient, subject and message prefilled — they just review and tap send. Q: Can I leave the subject and message blank? A: Yes. Only the recipient is required; subject and body are optional and only included when you fill them in. Q: Is my email content uploaded anywhere? A: No. The mailto link and QR code are generated entirely in your browser; nothing is sent to a server. Q: What is encoded inside an email QR code? A: A standard mailto URI, for example mailto:hello@example.com?subject=Hello&body=Your%20message. The recipient sits after mailto: and the subject and body are URL-encoded query parameters, which is why any scanner can read it without special software. Q: Will the email send automatically when scanned? A: No, and that is by design. Scanning opens a prefilled draft in the person's mail app; they still review it and tap send. This keeps the user in control and avoids accidental messages. Q: Which apps can scan an email QR code? A: Any modern phone camera or QR app. iPhone and most Android cameras detect the mailto link automatically and offer to open the mail app — no dedicated reader needed. Q: Should I download the QR code as PNG or SVG? A: Use PNG for slides, documents and social posts where a fixed-size image is fine. Use SVG for print — business cards, posters, packaging — because it stays razor-sharp at any size. #### Dice Roller URL: https://geratools.com/dice-roller Free online dice roller for d4, d6, d8, d10, d12, d20 and d100 with custom dice counts and modifiers. Uses the Web Crypto API for fair rolls and runs entirely in your browser — nothing is uploaded. How to use: 1. Pick your dice: Choose the dice type (d4 through d100) and how many to roll. 2. Add a modifier: Optionally enter a positive or negative modifier added to the total. 3. Roll: Click Roll to see each die result and the combined total. FAQ: Q: Which dice can I roll? A: You can roll any number of d4, d6, d8, d10, d12, d20 or d100 dice, plus an optional modifier added to the total — covering most tabletop and RPG needs. Q: What does a notation like 2d6+3 mean? A: It means roll two six-sided dice and add a modifier of 3 to the total. Set the dice type to d6, the count to 2 and the modifier to 3, then roll — the tool shows each die and the final total including the modifier. Q: Are the rolls fair? A: Yes. Each die uses the browser's Web Crypto API with modulo bias removed, so every face is equally likely on every roll. Q: How does removing modulo bias work? A: A raw random 32-bit value mapped onto, say, 1-20 with a plain modulo would slightly favour the lower faces. The roller discards values in the small leftover range and re-draws, so every face has exactly equal probability. Q: Can I roll many dice at once? A: Yes — you can roll from 1 up to 100 dice in a single click. Each die is rolled independently and the results are summed, then any modifier is added to give the total. Q: Can the modifier be negative? A: Yes. Enter a negative modifier to subtract from the total, for example a penalty on a skill check. The tool shows whether the modifier is added or subtracted in the breakdown. Q: Is my roll data shared anywhere? A: No — all rolling happens locally in your browser using the Web Crypto API. Nothing is uploaded or recorded. #### Random Team Picker URL: https://geratools.com/random-team-picker Free random team picker that splits a list of names into balanced teams using a fair shuffle. Runs entirely in your browser with the Web Crypto API — nothing is uploaded. How to use: 1. Enter the names: Type or paste each name on its own line. 2. Choose how many teams: Set the number of teams to split everyone into. 3. Pick teams: Click Pick teams to get balanced, randomly assigned groups. FAQ: Q: Are the teams balanced? A: Yes. Names are shuffled fairly, then dealt round-robin into teams, so team sizes never differ by more than one person. Q: How random is the assignment? A: The tool shuffles your list with an unbiased Fisher–Yates shuffle driven by the browser's Web Crypto API, so every arrangement is equally likely. Q: What happens if names do not divide evenly? A: They are dealt round-robin, so the extra people are spread out one per team. For example, 10 names into 3 teams gives team sizes of 4, 3, and 3 — never differing by more than one. Q: How do I enter the names? A: Type or paste each name on its own line. Blank lines are ignored, so you can paste a list straight from a document or spreadsheet column. Q: Can I re-pick if I do not like the result? A: Yes. Click Pick teams again for a completely new random arrangement. Each click reshuffles, so the groups change every time. Q: Is this fair for picking sports or game teams? A: Yes. Because it uses an unbiased shuffle with a cryptographically strong random source, no one has a higher chance of any team, making it genuinely fair for sports, classrooms, and game nights. Q: Are the names I enter uploaded anywhere? A: No — the names stay in your browser and the entire shuffle runs locally. Nothing is uploaded. #### Lottery Number Picker URL: https://geratools.com/lottery-number-picker Free lottery number picker that generates unique numbers for any draw format, with an optional bonus or lucky number. Uses the Web Crypto API and runs entirely in your browser — nothing is uploaded. How to use: 1. Set the draw format: Enter the highest number in the pool and how many numbers to pick. 2. Add a bonus pool: Optionally set a separate bonus pool size for a lucky or bonus ball. 3. Pick numbers: Click Pick numbers to get a sorted set of unique lottery numbers. FAQ: Q: Can I match my local lottery format? A: Yes. Set the pool size and how many to pick (for example 6 from 49), plus an optional bonus pool, to match most national and state lotteries. Q: Are the picked numbers unique? A: Yes. The main numbers are drawn without repeats using an unbiased shuffle, and they are returned sorted in ascending order. Q: Is anything uploaded when I pick numbers? A: No — numbers are generated locally in your browser using the Web Crypto API. Nothing is uploaded or saved. Q: Is the bonus ball drawn from the same pool as the main numbers? A: No. The bonus number comes from its own separate pool, matching real lotteries where the bonus or lucky ball is drawn independently and can coincide with a main number. Q: How do I set it up for a 6-from-49 lottery? A: Set the number pool to 49 and the count to pick to 6. For a bonus ball, set a separate bonus pool size as well. The tool then draws six unique numbers plus the bonus. Q: Are the numbers truly random? A: They use the browser's Web Crypto API (crypto.getRandomValues) with rejection sampling to avoid modulo bias, which is cryptographically secure randomness — far stronger than ordinary Math.random. Q: Does using this improve my odds of winning? A: No. Every combination has exactly the same chance in a fair lottery, so a random pick is neither better nor worse than any other. This tool simply saves you choosing and guarantees a valid, unique set. #### Crypto Address QR Code Generator URL: https://geratools.com/crypto-address-qr-code Free crypto address QR code generator for Bitcoin, Ethereum, Litecoin and Dogecoin. Encode a wallet address with optional amount into a scannable code. Runs entirely in your browser — nothing is uploaded. How to use: 1. Pick your coin: Choose Bitcoin, Ethereum, Litecoin, Dogecoin, or a raw address for any other chain. 2. Paste your address: Paste your receiving wallet address and optionally set an amount and label. 3. Download and share: Save the QR code as PNG or SVG and add it to invoices, donation pages or signs. FAQ: Q: Which wallet formats does this support? A: It builds standard payment URIs (such as bitcoin:address?amount=…) for Bitcoin, Ethereum, Litecoin and Dogecoin, plus a raw mode that encodes any address verbatim for other chains. Q: Is it safe to put my receiving address in a QR code? A: Yes — a receiving address is public information meant to be shared. Never put a private key or seed phrase into any QR generator. Q: What is a BIP-21 payment URI? A: BIP-21 is the Bitcoin standard for payment URIs like bitcoin:address?amount=0.05&label=Shop. Most wallet apps recognise it and prefill the address, amount and label when you scan it. Ethereum uses the similar EIP-681 scheme. Q: Should I set an amount on the QR code? A: It is optional. Adding an amount means the payer's wallet prefills it, which reduces mistakes for fixed-price payments. Leave it blank for donations or variable amounts so the payer enters their own figure. Q: Is my address uploaded anywhere? A: No. The payment URI and QR code are generated entirely in your browser; nothing is sent to a server. Q: Why do some Bitcoin QR codes look less dense than others? A: BIP-173 allows bech32 addresses (bc1…) to be written in all-uppercase, which lets QR encoders use the compact alphanumeric mode instead of byte mode. The result is a smaller, easier-to-scan code. Mixed case is invalid in bech32 — use all-upper or all-lower. Q: Can one QR code receive ERC-20 tokens like USDC? A: A plain address QR works for any asset sent to that address, but it cannot specify which token to send. An EIP-681 URI can reference the token contract, though wallet support varies — at minimum, label the QR clearly with the asset and network you expect (for example "USDC on Ethereum mainnet"). #### White Noise Generator URL: https://geratools.com/white-noise-generator Free white noise generator that plays white, pink, or brown noise synthesised in your browser with the Web Audio API. Adjustable volume, seamless loop, no audio download and nothing uploaded. How to use: 1. Pick a noise type: Choose white for an even hiss, pink for a softer rain-like sound, or brown for a deep rumble. 2. Set the volume: Drag the volume slider to a comfortable level — changes apply instantly while it plays. 3. Press play: Start the sound; it loops seamlessly for as long as the tab stays open, and you can stop it any time. FAQ: Q: What is the difference between white, pink and brown noise? A: White noise has equal energy at every frequency (an even hiss). Pink noise reduces higher frequencies for a softer, balanced sound like steady rain. Brown noise drops the highs further for a deep, rumbling tone like a waterfall. Q: Which noise colour is best for sleep? A: Many people find pink or brown noise more relaxing for sleep because the softer high frequencies are less harsh than white noise. There is no single right answer — try each and pick the one that helps you switch off. Q: Which noise colour is best for focus? A: White or pink noise is commonly used to mask office chatter and keyboard sounds while working. Brown noise suits people who prefer a deeper, less hissy background. Set the volume just high enough to cover distractions. Q: Is an audio file downloaded to play the noise? A: No. The sound is synthesised in real time in your browser with the Web Audio API, so nothing is downloaded and nothing is uploaded. Q: Can it play continuously? A: Yes. The noise loops seamlessly for as long as the tab is open and the device is awake. Disable any auto-sleep on your device if you want it to run all night. Q: Why does the noise stop when I lock my phone? A: Browsers pause Web Audio when a tab is suspended to save battery. Keep the tab in the foreground and prevent the screen from sleeping for uninterrupted playback. Q: Is white noise safe to listen to? A: At a moderate volume it is generally considered safe. As with any audio, avoid high volumes for long periods to protect your hearing, especially with headphones. #### Random Fact Generator URL: https://geratools.com/random-fact-generator Free random fact generator with a curated set of surprising, true "did you know?" facts. Tap for a new fact, picked with secure randomness. Runs entirely in your browser — no accounts, no tracking, nothing uploaded. How to use: 1. Tap the button: Press the button to pull a random fact from the curated list. 2. Read the fact: A surprising, true "did you know?" fact appears instantly. 3. Get another: Tap again for a new fact — it avoids repeating the last one. FAQ: Q: Are the facts true? A: Yes — the facts are drawn from a curated list of well-known, verifiable trivia chosen for being surprising but accurate. Q: Will I see the same fact twice in a row? A: No. The generator remembers the last fact shown and picks a different one on your next tap so you never get an immediate repeat. Q: Where do the facts come from? A: They are a hand-curated, bundled list of well-known, verifiable trivia — the kind of "did you know?" facts chosen for being both surprising and accurate. There is no live feed or AI generation, so nothing inaccurate gets injected. Q: Can I use these facts in a presentation or post? A: Yes. The facts are general-knowledge trivia, so they make good icebreakers, social captions, classroom warm-ups, or filler for slides. As with any fact, double-check before citing it in formal work. Q: How is each fact chosen? A: Each tap picks a fact at random from the bundled list using the browser secure random generator, while excluding the one currently shown so you never get the same fact twice in a row. Q: Does this need an internet connection or send any data? A: No. All facts are bundled into the page, so it works offline once loaded and never sends or stores any data. #### Spotify Link QR Code Generator URL: https://geratools.com/spotify-link-qr Free Spotify QR code generator. Paste a track, album, playlist, artist or podcast link and download a QR code that opens it in Spotify. The si tracking parameter is stripped, and everything runs in your browser. How to use: 1. Copy the Spotify link: In Spotify, use Share then Copy Link on any track, album, playlist, artist or podcast. 2. Paste it in: Paste the link here — the si tracking parameter is removed automatically. 3. Download and share: Save the QR code as PNG or SVG to print on posters, packaging or merch. FAQ: Q: What can I make a Spotify QR code for? A: Anything with a Spotify share link — a song, album, playlist, artist page, or podcast episode. The code opens it directly in the Spotify app or web player. Q: Why is the si parameter removed? A: Spotify appends an "si" tracking token to shared links, and this tool also removes "nd" and "context" parameters. Stripping them keeps your QR code clean and free of a referral identifier. Q: Does it accept spotify URIs as well as web links? A: Yes. A spotify URI such as spotify colon track colon id is encoded as-is, and a normal open.spotify.com link is cleaned of tracking parameters first. Q: Is this an official Spotify Code? A: No. This is a standard QR code that encodes your Spotify URL. It is not affiliated with Spotify and works with any QR scanner, unlike Spotify's own scannable Codes which only work inside the Spotify app. Q: PNG or SVG — which format should I pick? A: PNG suits screens and social posts; SVG is resolution-independent and best for print, large posters, or merch where the code may be scaled up. Q: Is my link uploaded anywhere? A: No. The QR code is generated entirely in your browser — your link is never sent to a server. #### YouTube Link QR Code Generator URL: https://geratools.com/youtube-link-qr Free YouTube QR code generator. Paste a video, playlist or channel link — or just a video ID — and download a QR code that opens it on YouTube. Tracking parameters are stripped and everything runs in your browser. How to use: 1. Copy the YouTube link: Use Share then Copy on a video, or grab the URL of a playlist or channel. 2. Paste or type the ID: Paste the full link, or just the 11-character video ID — both work. 3. Download the code: Save as PNG or SVG to print on slides, flyers, or product packaging. FAQ: Q: Can I keep the timestamp in the link? A: Yes. If your link includes a start time (the t parameter), it is preserved, so the video opens at the exact moment you chose. Q: Which tracking parameters are removed? A: Everything except the video ID, playlist, and timestamp is stripped — so referral and campaign tags are not baked into your code. Q: Does the QR code expire? A: No. The YouTube URL is encoded directly into the code, so it works as long as the video or channel exists on YouTube. Q: Can I download the QR code as PNG and SVG? A: Yes. The code renders on a canvas you can save as a PNG, and there is also a vector SVG download that stays crisp at any print size, from a slide thumbnail to a poster. Q: Will a bare 11-character video ID work? A: Yes. If you paste an 11-character ID like dQw4w9WgXcQ, the tool expands it to a full https://www.youtube.com/watch?v=… link before encoding it. Q: What error correction level does the code use? A: It uses level M (medium), which can recover from roughly 15% damage. That balances scan reliability with a code that stays compact enough for short YouTube URLs. Q: Why is the QR code red? A: The foreground is drawn in YouTube red on a white background for instant brand recognition. The colours do not affect scanning as long as there is strong contrast. #### Instagram QR Code Generator URL: https://geratools.com/instagram-qr Free Instagram QR code generator. Enter your handle or paste a profile, post or reel link and download a QR code that opens it in Instagram. Tracking parameters are removed and everything runs in your browser. How to use: 1. Enter your handle: Type your Instagram username with or without the @, and we build the profile link. 2. Or paste a link: Paste a full profile, post, or reel URL instead — tracking parameters are removed. 3. Download to share: Save the QR code as PNG or SVG for shop windows, packaging, or print ads. FAQ: Q: Do I need to include the @ in my handle? A: No. You can type it with or without the @ — the code builds the same instagram.com profile link either way. Q: Can I link to a specific post or reel? A: Yes. Paste the full post or reel URL and the QR code will open that exact content in Instagram. Q: Is this an official Instagram QR code? A: This is a standard QR code that encodes your Instagram URL. It works with any phone camera and is not affiliated with Instagram. Q: Can I download the QR code as an SVG? A: Yes. You can save it as a PNG for everyday use or as a vector SVG, which scales to any size without blurring — ideal for large print like posters and shop windows. Q: Why are tracking parameters removed? A: Pasted Instagram links often carry analytics query parameters (like igshid or utm tags). The generator strips these so the QR code resolves to a clean, stable URL that will not break or expose tracking. Q: Does the QR code expire? A: No. It simply encodes a URL, so it keeps working as long as that Instagram profile, post or reel exists. There is no account or short-link that could expire. #### WhatsApp Click-to-Chat QR Code Generator URL: https://geratools.com/whatsapp-click-to-chat-qr Free WhatsApp click-to-chat QR code generator. Enter your number and an optional prefilled message to create a wa.me QR code that opens a chat with you in one scan. Built entirely in your browser — nothing is uploaded. How to use: 1. Enter your number: Type your WhatsApp number including the country code. Spaces, brackets and a leading plus are removed automatically. 2. Add a message: Optionally write a message that will be prefilled when someone starts the chat. 3. Download and display: Save the QR code as PNG or SVG for your counter, receipt, flyer or website. FAQ: Q: What is a click-to-chat link? A: A wa.me link opens a WhatsApp conversation with a specific number, optionally with a message already typed. Scanning the QR code does the same with no contact saving needed. Q: How should I format the phone number? A: Include the full country code (for example 44 for the UK) with no plus, spaces or symbols. The tool strips anything that is not a digit for you, so a leading + or brackets are fine to type. Q: Does it work with WhatsApp Business? A: Yes. The wa.me link works with both personal and Business numbers, making it ideal for customer enquiries from a poster or receipt. Q: Can the QR code prefill a message? A: Yes. Whatever you type in the message field is URL-encoded and added as the text parameter, so the chat opens with that message ready for the sender to send. Q: What QR formats can I download? A: You can save the code as a PNG raster image for documents and social posts, or as an SVG vector for crisp printing at any size on signs and flyers. Q: Do scanners need a special app? A: No. Modern phone cameras on iOS and Android recognise the wa.me URL directly and offer to open WhatsApp, so guests do not need a separate QR app. Q: Is my number or message uploaded? A: No. The wa.me link is assembled and the QR code rendered entirely in your browser, so nothing is sent to any server. #### Sudoku Generator URL: https://geratools.com/sudoku-generator Free sudoku generator. Create printable 9x9 sudoku puzzles in easy, medium, or hard difficulty, each verified to have a single unique solution, with a reveal-solution button. Runs entirely in your browser. How to use: 1. Pick a difficulty: Choose easy, medium, or hard to control how many starting clues the puzzle keeps. 2. Generate the puzzle: Click Generate puzzle to build a fresh 9x9 grid with a single unique solution. 3. Solve or reveal: Solve it on paper after printing, or click Show solution to reveal the answers. FAQ: Q: Does each puzzle have only one solution? A: Yes. After removing clues the generator runs a solver on the remaining grid and only keeps a removal if the puzzle still has exactly one unique solution, so there is never any guessing ambiguity. Q: What do the difficulty levels mean? A: Difficulty controls the number of given clues — easy keeps around 40, medium around 32, and hard around 26. Fewer clues generally means a harder solve. Q: How is a fully-solved grid created first? A: The generator fills an empty 9x9 grid with a randomised backtracking algorithm that respects the row, column, and 3x3 box rules, producing a valid complete solution before any clues are removed. Q: How does it remove clues without breaking uniqueness? A: It tentatively clears cells and re-checks that only one solution remains. If removing a cell would create a second solution, that cell is kept, which guarantees a single answer. Q: Can I print the puzzle or save it as a PDF? A: Yes. Use your browser's print or save-as-PDF function on the generated grid. The solution stays hidden until you click Show solution, so you can print the puzzle alone. Q: Is my puzzle generated on a server? A: No. The full backtracking solver and puzzle generation run in your browser, so nothing is sent anywhere. #### Maze Generator URL: https://geratools.com/maze-generator Free maze generator. Build printable square mazes in small, medium, or large sizes, each a perfect maze with exactly one solution path from start to finish. Drawn as crisp SVG in your browser — nothing is uploaded. How to use: 1. Choose a size: Pick small, medium, or large to set how many cells wide and tall the maze is. 2. Generate: Click Generate maze to build a fresh random maze with a recursive backtracker. 3. Print: The maze is drawn as sharp vector graphics — print it or save it as a PDF from your browser. FAQ: Q: Does the maze always have a solution? A: Yes. The generator builds a perfect maze, meaning there is exactly one path between any two cells, so there is always a single route from the green start to the red finish. Q: Where are the start and finish? A: The start is the green dot in the top-left cell and the finish is the red dot in the bottom-right cell. Q: Is the maze created on a server? A: No. The maze is generated and drawn entirely in your browser, and nothing is uploaded. Q: What sizes are available? A: Three sizes: small (10×10 cells), medium (16×16) and large (24×24). Bigger grids mean longer, harder solution paths. Each is drawn as scalable vector graphics, so any size prints sharply. Q: How is the maze generated? A: It uses the recursive backtracker (randomised depth-first search). Starting from the top-left cell, it repeatedly carves a passage to a random unvisited neighbour and backtracks when stuck. This is what guarantees a perfect maze with exactly one path between any two cells. Q: Will each maze be different? A: Yes. The generator picks random neighbours as it carves, so every time you click Generate you get a fresh, unique maze even at the same size. Q: Can I save the maze as a PDF? A: Yes. Because the maze is drawn as SVG vector graphics, you can use your browser print dialog and choose "Save as PDF", or print it directly. It stays crisp at any paper size. #### Word Search Generator URL: https://geratools.com/word-search-generator Free word search generator. Enter your own word list and build a printable letter grid that hides them in 8 directions including diagonals and backwards. Everything runs in your browser — nothing is uploaded. How to use: 1. Enter your words: Type the words you want to hide, one per line or separated by commas. 2. Set the grid size: Choose a grid size from 6 to 20. Words longer than the grid are skipped. 3. Generate and print: Click Generate puzzle to place the words and fill the rest with random letters, then print or save as a PDF. FAQ: Q: Which directions can the words run? A: Words are hidden in all 8 directions — horizontal, vertical, both diagonals, and any of those reversed (backwards), which makes the puzzle harder to scan. Q: How do I enter my word list? A: Type the words you want to hide, one per line or separated by commas. They are placed into the grid and the remaining cells are filled with random letters. Q: Why was one of my words skipped? A: A word is skipped if it is longer than the grid or if the generator cannot fit it after many placement attempts. Skipped words are flagged in the word list. Try a larger grid or shorter words. Q: How do I print or save the puzzle? A: Use your browser's print command and choose Save as PDF to keep a copy, or print directly. The grid and word list are laid out for a clean printed page. Q: What grid size should I choose? A: Pick a size from 6 to 20 to match your longest word and difficulty. Smaller grids are easier for young children; larger grids hold more and longer words for a harder challenge. Q: Can I make the same puzzle again? A: Each generation places words and random fillers afresh, so regenerating produces a new layout. Print or save the version you like before generating another. Q: Are my words uploaded anywhere? A: No. The grid is generated in your browser from your word list, and nothing is sent to a server. #### Random Team Name Generator URL: https://geratools.com/random-team-name Generate punchy random team names by pairing a bold adjective with a strong noun. Great for sports teams, pub quizzes, gaming squads and work groups. Runs entirely in your browser. How to use: 1. Choose how many ideas: Enter how many team names you want, from 1 to 50. 2. Generate: Press the button to pair a random adjective with a random noun for each name. 3. Pick a favourite: Regenerate as many times as you like until a name jumps out at you. FAQ: Q: What kind of team names does it create? A: Each name pairs a bold adjective such as Mighty or Cosmic with a strong noun such as Wolves or Titans, giving punchy two-word names that suit sports teams, quiz nights, gaming squads and work groups. Q: Can I get more than one at a time? A: Yes — choose any number from 1 to 50 and the tool generates a full list in one click so you can compare options. Q: Are these team names original and free to use? A: Yes. The names are assembled from generic adjectives and nouns, so they are free for casual use in sports, quizzes, gaming and work. For a registered brand or trademark, do your own availability and trademark check. Q: How many possible names can it make? A: Because every name pairs one adjective with one noun, the number of possible combinations is the size of the adjective list multiplied by the size of the noun list — typically hundreds of distinct two-word names. Q: Can I make a name longer or different? A: The tool produces two-word adjective + noun names. If you want something longer, use a generated name as a base and add a place, year, or third word yourself, e.g. "Cosmic Wolves United". Q: What makes a good team name? A: Short, memorable, easy to chant or type, and a little bold. The adjective + noun pattern this tool uses (like Iron Titans) hits all of those, which is why it is common for sports, esports, and quiz teams. Q: Are the names sent anywhere? A: No. Names are assembled locally in your browser from built-in word lists, so nothing is uploaded. #### Tournament Bracket Generator URL: https://geratools.com/tournament-bracket-generator Free single-elimination tournament bracket generator. Paste your teams or players, seed or shuffle the draw, auto-handle byes, click to advance winners, and export the bracket. Runs entirely in your browser. How to use: 1. Enter your entrants: Type or paste the teams or players, one per line (commas also work). Duplicates are removed automatically. 2. Choose seeded or shuffled: Build seeded keeps your entry order as the seeding (entry 1 is the top seed); build shuffled randomises the draw. 3. Advance the winners: Click a name in any match to mark it the winner. The bracket fills the next round automatically until a champion is crowned. 4. Export or re-roll: Re-shuffle the draw, copy the bracket to your clipboard, or download it as text or JSON to share with everyone. FAQ: Q: How does single-elimination seeding work? A: Seeds are placed so the strongest entrants meet as late as possible: seed 1 plays the lowest seed, seed 2 is put in the opposite half, and so on (1 v 16, 8 v 9, 5 v 12, 4 v 13 in a 16-slot bracket). This generator uses that standard seeding so a seeded bracket gives top seeds the easiest early path, while a shuffled bracket ignores seeds and draws everyone at random. Q: What happens if I do not have a power-of-two number of entrants? A: The bracket is rounded up to the next power of two (4, 8, 16, 32...) and the empty slots become byes. A bye is auto-resolved: the real entrant facing it advances to round two without playing, exactly like a paper bracket. Top seeds receive the byes first, which is the fair convention. Q: Can I change a result after I have already picked winners? A: Yes. Click the other name in any match to switch the winner. Any later rounds that depended on the old result are cleared and recalculated, so the champion and every downstream match stay consistent. Nothing is locked. Q: How many teams or players does it support? A: It handles anything from 2 up to 128 entrants, covering everything from a quick four-team office contest to a large 128-player knockout. Beyond 128 the list is trimmed to keep the bracket readable on screen. Q: Is my bracket saved if I close the tab? A: Yes. The current bracket, including every result you have picked, is stored in your browser's localStorage and restored when you return. Use the Clear button to wipe it and start fresh. Nothing is ever uploaded to a server. Q: Can I share the finished bracket? A: Use Copy to put a clean text version on your clipboard, Export text for a plain .txt file, or Export JSON for a structured file you can re-import elsewhere or process with code. The text export lists the entrants, every round, the winner of each match, and the champion. #### Tournament Bracket Generator URL: https://geratools.com/tournament-bracket Free single-elimination tournament bracket generator. Enter your teams or players, draw a seeded bracket with automatic byes, record scores so winners advance themselves, then export a printable PDF or SVG. Runs entirely in your browser — nothing is uploaded. How to use: 1. List your entrants: Type each team or player on its own line in the entrants box. Two to sixty-four entrants are supported. 2. Choose the draw: Generate a bracket directly, shuffle the entrants for a random draw, or toggle between standard seeding and entry order. 3. Record scores as matches finish: Type each side''s score under "Record scores". The winner advances automatically into the next round and the champion appears once the final is decided. 4. Export the bracket: Click "Export printable PDF" for a clean A4 sheet, or "Export SVG" for a sharp vector file you can edit or scale. FAQ: Q: What is a single-elimination bracket? A: A single-elimination (or knockout) bracket is a tournament format where the loser of every match is immediately out. Winners advance through rounds — quarter-finals, semi-finals, final — until one entrant remains as champion. It is the format used by most cup competitions, playoff series and weekend tournaments because it produces a winner in the fewest possible matches. Q: How are byes handled when my entrant count is not a power of two? A: Brackets need a power-of-two number of slots (2, 4, 8, 16, 32, 64). When your entrant count falls between those, the generator pads the bracket with byes and assigns them so the top seeds get the free passes. Any entrant drawn against a bye advances automatically to the next round with no match required. Q: What does seeding do? A: Standard seeding orders the bracket so the strongest entrants are kept apart for as long as possible — seed 1 only meets seed 2 in the final, seed 1 plays the lowest seed in round one, and so on. Toggle to entry order if you would rather pair entrants exactly as you typed them, or use Shuffle for a fully random draw. Q: Do winners advance automatically? A: Yes. As soon as you enter two different scores for a match, the higher score wins and that entrant is written into the correct slot in the next round. Change a score later and the whole downstream tree re-computes, so corrections cascade correctly all the way to the champion. Q: Is my bracket saved if I close the tab? A: Your tournament name, entrants and every recorded score are saved in your browser''s local storage, so reopening the page restores exactly where you left off. Nothing is sent to a server, so the data stays on the device you used. Clearing your browser storage removes it. Q: What can I do with the exported files? A: The PDF is a print-ready A4 sheet — ideal for pinning to a wall, handing to officials or sharing as a fixture list. The SVG is a resolution-independent vector you can open in design tools, embed on a website or scale to any poster size without blurring. ### Reference #### Guitar Tuning Reference URL: https://geratools.com/guitar-tuning-reference Reference table of note names and exact frequencies for standard, drop D, half-step down, DADGAD and open G guitar tunings, with an adjustable A4 reference. Runs entirely in your browser. How to use: 1. Pick a tuning: Select standard, drop D, half-step down, DADGAD or open G from the list. 2. Set the reference pitch: Leave A4 at 440 Hz or change it to match the pitch you are tuning to. 3. Match each string: Tune each string to the note and frequency shown, from the low 6th string to the high 1st. FAQ: Q: What are the frequencies of standard guitar tuning? A: Standard EADGBE at A4 = 440 Hz is E2 ≈ 82.41 Hz, A2 = 110.00 Hz, D3 ≈ 146.83 Hz, G3 = 196.00 Hz, B3 ≈ 246.94 Hz and E4 ≈ 329.63 Hz, from the lowest to the highest string. Q: How is drop D different from standard? A: Drop D lowers only the 6th string from E2 to D2, leaving the other five strings unchanged. It makes power chords on the low strings playable with one finger. Q: What notes are in DADGAD tuning? A: DADGAD tunes the strings, low to high, to D A D G A D. It is an open Dsus4-style tuning popular in Celtic and fingerstyle playing for its ringing, modal sound. Q: What is open G tuning? A: Open G tunes the strings to D G D G B D, so strumming the open strings sounds a G major chord. It is widely used for slide guitar and in rock by players like Keith Richards. Q: What is half-step down tuning? A: Half-step down (E♭ A♭ D♭ G♭ B♭ E♭) lowers every string by one semitone from standard. It slightly slackens the strings and drops the overall pitch, common in rock and blues. Q: Why can I change the A4 reference from 440 Hz? A: A4 = 440 Hz is modern concert pitch, but some orchestras and players tune to 441-443 Hz, or to 432 Hz. Adjusting the reference rescales every string frequency proportionally so the table matches your chosen pitch. Q: Is this an audio tuner? A: No — it is a reference table of target frequencies. Use it alongside a tuner or your ear. No microphone or network access is used. #### Planetary Data Reference URL: https://geratools.com/planetary-data-reference Free reference table of planetary data — diameter, mass, surface gravity, distance from the Sun, orbital period, day length and moons for all eight planets plus Pluto. Runs entirely in your browser. How to use: 1. Search a planet: Type a planet name to filter the table, or leave it blank to see all of them. 2. Compare the columns: Read diameter, mass, gravity, distance, orbit, day length and moon count side by side. 3. Use the AU note: Distances are in astronomical units (AU), where 1 AU is the mean Earth–Sun distance. FAQ: Q: Where does this data come from? A: Values are rounded from NASA planetary fact sheets — equatorial diameter, mass relative to Earth, mean surface gravity, mean orbital distance in AU, orbital period in Earth years, sidereal rotation period and known moon counts. Q: Why is Pluto included if it is not a planet? A: Pluto is included as a dwarf planet for reference, clearly labelled, because it is still commonly looked up alongside the eight planets. Q: Which planet is the largest? A: Jupiter is the largest planet, with an equatorial diameter of about 142,984 km and a mass 317.8 times Earth's — more than all the other planets combined. Q: Which planet has the most moons? A: By this reference, Saturn leads with about 146 known moons, narrowly ahead of Jupiter at about 95. Moon counts keep rising as surveys discover more small satellites. Q: What is an astronomical unit (AU)? A: One AU is the mean Earth–Sun distance, about 149.6 million km. Distances in the table are given in AU, so Mars at 1.52 AU is just over 1.5 times Earth's distance from the Sun. Q: Why is a day on Venus so long? A: Venus rotates very slowly, taking about 2,802 hours (roughly 117 Earth days) for one rotation — longer in some respects than its 0.62-year orbit, and it spins in the opposite direction to most planets. Q: Is anything uploaded? A: No — this is a static reference table that runs entirely in your browser. ### More Apps #### Microphone Test URL: https://geratools.com/microphone-test Free online microphone test. Speak and watch a live input-level meter with a peak reading to confirm your mic works before a call or recording. Audio is analysed in your browser and never recorded or uploaded. How to use: 1. Start the test: Press Start microphone test and allow browser access when prompted. 2. Speak normally: Talk at your usual call volume and watch the level meter respond. Normal speech should fill a healthy part of the bar. 3. Check the peak: The peak marker records the loudest moment. If the meter barely moves, your mic is muted, unselected or faulty. FAQ: Q: How do I test my microphone online? A: Press Start microphone test and grant permission when the browser asks. Speak at normal volume and watch the level meter move in real time. A responsive bar means the mic is working and being picked up correctly. Q: Is my audio recorded or uploaded? A: No. The tool measures the loudness of your input in your browser using the Web Audio API. No audio is ever recorded, saved or transmitted — only a moving level bar is shown, and it stops the instant you press Stop. Q: The meter is not moving — what is wrong? A: Usually the mic is muted, the wrong input device is selected in your system settings, or permission was denied. Check the system input, un-mute the microphone, confirm the browser has permission, and try again. Q: What is a good microphone level? A: For a call or recording you want normal speech to move the meter into the middle-to-upper range without constantly hitting the top. If it maxes out and turns amber, lower your input gain; if it barely registers, raise the gain or move closer. Q: Does this work with USB, Bluetooth and built-in mics? A: Yes. Any microphone your operating system recognises — built-in, USB, headset or Bluetooth — can be tested, as long as it is set as the active input and the browser has permission. #### Gamepad Tester URL: https://geratools.com/gamepad-tester Free online gamepad tester. Connect a controller and watch every button and analog stick respond live to check it works, find a sticky button or measure stick drift. Uses the browser Gamepad API — nothing is uploaded. How to use: 1. Connect your controller: Plug in a USB controller or pair it over Bluetooth, then press any button so the browser detects it. 2. Press every button: Work through each button and trigger. Its box lights up and shows a 0 to 1 value, so you can confirm every input registers. 3. Move the sticks fully: Push each analog stick to all edges. The dot should reach the extremes and return to the exact centre when released. FAQ: Q: How do I test my game controller in the browser? A: Connect the controller by USB or Bluetooth and press any button to wake it — browsers only report a gamepad after its first input. Every button and axis then updates live so you can confirm each one works. Q: How do I check for stick drift? A: Release both analog sticks and watch the axis values and dot position. On a healthy stick they rest at or very near zero (centre). If a value stays noticeably off-centre or the dot wanders while untouched, the stick has drift. Q: Why is my controller not detected? A: The Gamepad API only exposes a controller after it sends its first input, so press a button. If it still does not appear, check the cable or Bluetooth pairing, make sure the browser tab is focused, and confirm the controller is charged. Q: Which controllers work with this tester? A: Any controller the browser Gamepad API recognises, which includes most Xbox, PlayStation and generic USB and Bluetooth gamepads. Button numbering may differ slightly between models, but every input still registers. Q: Is any data collected? A: No. The tester only reads button and axis values from the browser and displays them. Nothing about your controller or inputs is stored or uploaded. #### Click Speed Test (CPS Test) URL: https://geratools.com/click-speed-test Free CPS test — click as fast as you can and measure your clicks per second over a window you choose. Shows live CPS, total clicks and your best score. Runs entirely in your browser, nothing uploaded. How to use: 1. Pick a test length: Choose how long the test runs — 1, 5, 10, 30 or 60 seconds. The 5-second test is the most common CPS benchmark. 2. Start clicking: Click anywhere in the test pad to begin. The clock starts on your first click, so no reaction time is wasted. 3. Read your CPS: When the timer ends, your clicks-per-second score is shown alongside your total clicks and your best score this session. FAQ: Q: What is a good CPS score? A: A typical fast clicker manages around 6 to 8 clicks per second. Techniques like jitter clicking and butterfly clicking can push well into double digits, while a relaxed click sits closer to 4 to 5 CPS. Q: How is CPS calculated? A: Clicks per second is your total number of clicks divided by the length of the test in seconds. A 5-second test with 35 clicks gives 35 divided by 5, which is 7 CPS. Q: Does the clock start before I click? A: No. The timer starts on your very first click inside the pad, so your reaction time is never counted against your score. Q: Is anything recorded online? A: No. The test runs entirely in your browser and your scores stay on the page until you reload — nothing is sent to a server. #### Number Memory Test URL: https://geratools.com/number-memory-test Free number memory test. A number flashes on screen, then you type it from memory; each correct answer adds a digit. See how long a number you can hold in short-term memory. Runs entirely in your browser. How to use: 1. Watch the number: A number appears on screen for a short time that grows with its length. Memorise it before it disappears. 2. Type it back: When the input box appears, type the number exactly as you saw it and submit. 3. Climb the levels: Each correct answer adds one more digit for the next round. One wrong answer ends the run and shows the level you reached. FAQ: Q: How many digits can the average person remember? A: Most people can hold about seven digits in short-term memory, the classic digit span. With practice or chunking strategies, some push to ten or more. Q: How long is the number shown? A: The display time scales with the number length, so longer numbers stay on screen a little longer. This keeps the challenge about recall rather than reading speed. Q: Does it use real phone numbers or personal data? A: No. Every number is generated randomly in your browser at the moment of play; nothing is taken from any list and nothing is uploaded. Q: What is digit span? A: Digit span is the longest sequence of numbers you can recall in order immediately after seeing it. It is a standard measure of short-term verbal memory. #### Aim Trainer URL: https://geratools.com/aim-trainer Free online aim trainer. Targets pop up at random spots — click them as fast as you can over 10, 20 or 30 targets. Reports total time, time per target and accuracy. Runs entirely in your browser, nothing uploaded. How to use: 1. Choose a round length: Pick how many targets to clear in the round — 10, 20 or 30. 2. Click the targets: A red target appears at a random spot; click it and the next one spawns instantly. Misses are counted too. 3. Read your stats: After the last target you see your total time, average time per target, and accuracy as a percentage. FAQ: Q: What does an aim trainer measure? A: It measures how quickly and accurately you can move your cursor to a target and click it. The two key numbers are time per target and accuracy, the share of clicks that actually hit a target. Q: How is accuracy calculated? A: Accuracy is your hits divided by total clicks. If you clicked 25 times to hit 20 targets, that is 20 divided by 25, or 80 percent accuracy. Q: How can I improve my aim? A: Use a comfortable mouse sensitivity, keep your wrist and arm relaxed, and aim for a balance of speed and precision rather than frantic clicking. Consistent practice in short sessions tends to help most. Q: Is anything tracked online? A: No. The trainer runs entirely in your browser and your results stay on the page until you start a new round or reload. #### Online Metronome URL: https://geratools.com/online-metronome Free online metronome with adjustable tempo from 20 to 300 BPM, selectable time signatures and an accented first beat. Runs entirely in your browser — nothing is uploaded. How to use: 1. Set the tempo: Drag the slider or type an exact value to set the tempo between 20 and 300 beats per minute. 2. Choose a time signature: Pick how many beats are in each bar so the first beat of every bar is accented with a higher click. 3. Start the beat: Press Start. The metronome clicks in time and a row of dots shows the current beat in the bar. FAQ: Q: What tempo range does the metronome support? A: Anything from 20 to 300 beats per minute, set either with the slider or by typing an exact BPM value. Q: Why does the first beat sound different? A: The downbeat of each bar is accented with a higher-pitched, louder click so you can feel where each bar starts based on the time signature you choose. Q: What do BPM tempo markings like Andante and Allegro mean? A: They are traditional Italian tempo terms. Roughly, Largo is 40–60 BPM, Andante 76–108, Moderato 108–120, Allegro 120–168 and Presto 168–200. Set the slider to match the marking on your sheet music. Q: How should I use a metronome to get faster? A: Practise a passage cleanly at a comfortable BPM, then raise the tempo by 4–8 BPM only once you can play it without mistakes. Repeating this gradually trains accuracy before speed. Q: Does the metronome need an internet connection or send audio anywhere? A: No. The clicks are generated locally with the browser's Web Audio API. No audio files are downloaded and nothing is ever uploaded. #### World Clock — Multiple Cities URL: https://geratools.com/world-clock-multi-city Free multi-city world clock. View the live time and date in cities around the world side by side, with each zone's UTC offset and difference from your own time, including automatic daylight-saving handling. Privacy-first — runs entirely in your browser. How to use: 1. Add cities: Choose a city from the dropdown and press Add. Each city appears with its live local time, date and UTC offset. 2. Compare against your time: Each row shows how many hours that city is ahead of or behind your own device's time zone. 3. Switch the format: Toggle 12-hour mode for AM/PM display, and remove any city you no longer need with the × button. FAQ: Q: How are the time zones calculated? A: The clock uses your browser's built-in IANA time-zone database via the Intl API — the same data your operating system uses. This means daylight-saving transitions are applied automatically and correctly for each city. Q: How accurate are the times? A: The displayed times are as accurate as your device's own clock, ticking once per second. UTC offsets and the difference versus your local zone are computed live, so they update if a city crosses a daylight-saving boundary. Q: How do I find the time difference between two cities? A: Add both cities and read the "ahead of or behind your time" figure for each. Subtract those two values to get the difference between the cities — for example, a city at +5 and one at -3 are 8 hours apart. Q: Can I switch between 12-hour and 24-hour time? A: Yes. Toggle 12-hour mode for AM and PM display, or leave it off for 24-hour time. The setting applies to every city in your list at once. Q: Does it adjust for daylight saving time automatically? A: Yes. Because it relies on the IANA database, each city follows its own daylight-saving rules, so the times stay correct across spring-forward and fall-back transitions without any manual change. Q: Why is the time difference to a city not a whole number? A: Some zones use 30 or 45 minute offsets — India is UTC+5:30 and Nepal is UTC+5:45 — so the difference from your zone can include half or quarter hours. Q: Is any location or clock data sent to a server? A: No. Nothing is fetched and no location is shared — all time-zone conversions run locally in your browser using built-in browser data, so the tool works offline and keeps your activity private. #### World Clock — Multiple Time Zones URL: https://geratools.com/world-clock-multi-timezone Free world clock that shows the live time across multiple IANA time zones side by side, with offsets and the difference versus your device. DST-accurate and 100% in your browser. How to use: 1. Add time zones: Pick any IANA time zone (such as Europe/London or Asia/Tokyo) from the dropdown and press Add. 2. Read the times: Each row shows the live local time, the UTC offset, and how many hours it is ahead of or behind your device. 3. Switch the format: Toggle 12-hour to show AM/PM, or remove any zone you no longer need with the × button. FAQ: Q: Are daylight-saving changes handled? A: Yes. Times are computed with your browser built-in IANA time-zone database — the same one your operating system uses — so daylight-saving transitions are applied automatically. Q: Which time zones can I add? A: Any IANA zone your browser knows, listed by region and city (for example America/New_York or Pacific/Auckland). Older browsers fall back to a curated list. Q: What is the difference between this and the multi-city clock? A: This tool lets you pick raw IANA zone identifiers like Europe/London or Asia/Tokyo directly, which is useful for developers and precise scheduling. The multi-city version presents the same data labelled by familiar city names. Q: What is a UTC offset? A: It is how many hours a zone is ahead of or behind Coordinated Universal Time. London is UTC+0 in winter and UTC+1 in summer; New York is UTC-5 or UTC-4. The clock shows each zone's current offset. Q: Can I show 12-hour AM/PM time? A: Yes. Toggle the 12-hour option to display AM and PM, or leave it off for 24-hour time across every zone in your list. Q: How do I compare two zones quickly? A: Add both and look at each one's "ahead of or behind your device" value. The gap between those two numbers is the time difference between the zones. Q: Is any clock data fetched from a server? A: No. The current time comes from your device clock and all conversions happen locally — nothing is fetched or sent. #### Yes or No Oracle URL: https://geratools.com/yes-or-no-oracle Free yes-or-no oracle. Ask any question and get an instant Yes, No, or Maybe, decided with secure randomness. A simple way to settle a choice. Runs entirely in your browser — nothing is stored or uploaded. How to use: 1. Ask your question: Type any yes-or-no question into the box. 2. Consult the oracle: Press the button to get an instant verdict. 3. Read the answer: A clear Yes, No, or Maybe appears in colour. FAQ: Q: How does the yes-or-no oracle decide? A: It picks Yes, No, or Maybe using your browser's cryptographically secure random number generator, so each answer is independent and unbiased. Q: When should I use it? A: Use it to break a tie, settle a small decision quickly, or just for fun when you can't make up your mind between two simple options. Q: Is my question recorded? A: No. Your question stays on your device — the oracle runs entirely in your browser with no network calls and nothing stored. Q: Are the three answers equally likely? A: Yes, near enough. The tool maps a secure random byte (0–255) to one of three outcomes with modulo 3, giving each of Yes, No and Maybe roughly a one-in-three chance. Q: Does my question influence the answer? A: No. The verdict is purely random and ignores the text you type — the question box is just there to help you frame your decision before you commit to the result. Q: Is this the same as flipping a coin? A: It is similar but with three outcomes instead of two. A coin gives a 50/50 Yes or No, while the oracle adds a Maybe, splitting the odds roughly into thirds. Q: What is a cryptographically secure random number? A: It is randomness from your browser's crypto.getRandomValues, designed to be unpredictable and unbiased, unlike Math.random which is only pseudo-random and not meant for security. #### Crossword Grid Maker URL: https://geratools.com/crossword-grid-maker Free crossword grid maker. Lay out a blank crossword grid by clicking cells black or white, with optional 180-degree symmetry and automatic across and down clue numbering. Runs entirely in your browser — nothing is uploaded. How to use: 1. Set the grid size: Enter a grid size from 5 to 21 squares and optionally enable 180-degree rotational symmetry. 2. Block out squares: Click any square to toggle it black. With symmetry on, the mirror square is blocked at the same time. 3. Read the clue numbers: Numbers for across and down entries are computed automatically as you edit, following standard crossword rules. FAQ: Q: How are the clue numbers worked out? A: A white square is numbered if it begins an across word (its left edge is blocked and the square to its right is open) or a down word (its top edge is blocked and the square below is open). Numbering runs left to right, top to bottom. Q: What does 180-degree symmetry do? A: When enabled, blocking one square also blocks the square diametrically opposite it. This matches the rotational symmetry convention used in most published crosswords. Q: What grid sizes can I make? A: Square grids from 5×5 up to 21×21. A 15×15 is the standard daily-puzzle size, while 21×21 is the common Sunday-size grid. Q: How do I print the finished grid? A: Once you have blocked out your pattern, use your browser's print or save-as-PDF function. The grid and its numbers print as laid out on screen. Q: Is my grid saved to a server? A: No. The grid lives only in your browser while the page is open, and nothing is uploaded. #### Rock Paper Scissors URL: https://geratools.com/rock-paper-scissors Play rock paper scissors against the computer with a running score. Uses secure, unbiased randomness and runs entirely in your browser — nothing is uploaded. How to use: 1. Choose your move: Click Rock, Paper or Scissors to make your play. 2. See the result: The computer's move and the round result appear instantly. 3. Track your score: Wins, losses and draws tally up automatically — reset any time. FAQ: Q: Does the computer cheat? A: No. The computer picks its move with cryptographically secure randomness before comparing it to yours, so each round is fair and unbiased. Q: What are the rules? A: Rock beats Scissors, Scissors beats Paper, and Paper beats Rock. Matching moves are a draw. Q: Is anything sent to a server? A: No. The game runs entirely in your browser and no data is uploaded or stored. Q: Can I predict the computer's move? A: No. Each move is drawn fresh from a cryptographically secure random source with no pattern or memory of past rounds, so there is no strategy that beats it more than one-third of the time on average. Q: Does the score persist if I refresh? A: The running scoreboard tallies your wins, losses, and draws during play and can be reset any time. Refreshing the page starts a new session. Q: What happens on a tie? A: If both you and the computer pick the same move, the round is a draw — no win or loss is recorded, and you simply play again. Q: Is rock paper scissors purely luck? A: Against a truly random opponent like this one, yes — every choice has an equal one-third chance. Between humans it becomes a game of psychology and pattern-reading, but the computer here has no exploitable pattern. #### ICS Calendar Event Builder URL: https://geratools.com/ics-event-builder Free ICS event builder. Fill in event details, generate a valid RFC 5545 .ics file, and add the event to Google Calendar or Outlook in one click. Recurring events, reminders, time zones — all in your browser, nothing uploaded. How to use: 1. Fill in the event details: Enter a title, location, optional notes and a URL. Pick the start and end date and time, or tick All-day for a multi-day event. 2. Set recurrence and a reminder: Choose how often the event repeats (daily, weekly on chosen days, monthly, yearly), how many times, and an optional reminder before it starts. 3. Export or add to your calendar: Click Download .ics to save a file you can import anywhere, or use Add to Google / Add to Outlook to open the event pre-filled in your calendar. FAQ: Q: What is an .ics file and where can I use it? A: An .ics (iCalendar) file is the universal calendar interchange format defined by RFC 5545. Almost every calendar app reads it: Google Calendar, Apple Calendar, Microsoft Outlook, Thunderbird, Fastmail and more. Double-click or import the file and the event is added with its title, time, location, recurrence and reminders intact. Q: Does the tool create recurring events? A: Yes. You can repeat an event daily, weekly (on specific weekdays such as Mon, Wed, Fri), monthly or yearly, set an interval like every 2 weeks, and either stop after a number of occurrences or on an end date. The tool writes a standard RRULE so the recurrence is honoured by any calendar app. Q: How do the Add to Google and Add to Outlook buttons work? A: They build a pre-filled calendar link for Google Calendar and Outlook.com that opens the new-event screen with your title, time, location, description and recurrence already populated. You just review and save. The .ics download works for every other app, including Apple Calendar and desktop Outlook. Q: Are my event details sent anywhere? A: No. The entire file is generated in your browser using JavaScript. Nothing is uploaded to a server, and your most recent event is saved only in your own browser via local storage so you can return and edit it later. Q: How are time zones handled? A: You can attach an IANA time zone such as Europe/London or America/New_York, which writes a TZID so the event stays at the right local time wherever it is opened. Leave it on Floating to keep the same wall-clock time in every zone, or choose UTC. All-day events are date-only and ignore time zones by design. Q: Can I put more than one event in a single file? A: Yes. Add as many events as you like and Download .ics bundles them all into one calendar file, which is handy for sharing a schedule, an itinerary or a series of meetings. You can also download just the event you are currently editing. Q: Why is the end date one day later for all-day events? A: The iCalendar spec treats the all-day end date as exclusive, so a one-day event on the 10th is stored with an end of the 11th. The builder handles this automatically — you pick the last day the event covers and it writes the correct exclusive end so calendars show the right span. #### Recipe Manager URL: https://geratools.com/recipe-manager A free recipe manager that saves your recipes, scales the ingredients to any number of servings, and merges everything into an aisle-by-aisle shopping list. Runs entirely in your browser — nothing is uploaded. How to use: 1. Add your recipes: Create a recipe with its ingredients (quantity, unit, name), the base serving count and the method steps. Paste a whole ingredient list at once if you prefer. 2. Build a meal plan: Add recipes to the meal plan and set how many servings you want of each. The tool scales every ingredient automatically. 3. Get your shopping list: Open the shopping list to see every ingredient merged and grouped by supermarket aisle, then tick items off, copy or download it. FAQ: Q: How does scaling the servings work? A: Every recipe stores a base serving count. When you change the target servings, the tool multiplies each ingredient by target ÷ base. So a recipe written for 2 that you scale to 5 multiplies every quantity by 2.5. Fractions like a half teaspoon are rounded to readable amounts so you are not left measuring 0.83 of a cup. Q: How is the shopping list built? A: It walks through every recipe in your meal plan, scales each ingredient to the servings you chose, then merges identical ingredients that share the same unit so their amounts add up. The result is grouped into supermarket aisles like Produce, Dairy and Pantry so you shop in one pass instead of zig-zagging the store. Q: Why are ingredients with the same name not always combined? A: Ingredients are merged only when both the name and the unit match. "200 g flour" and "1 cup flour" use different units, so they stay separate rather than being added together incorrectly. Keep units consistent across recipes if you want them to combine. Q: Can I paste an ingredient list instead of typing each line? A: Yes. In the recipe editor, choose "Paste many" and drop in one ingredient per line, for example "200 g spaghetti" or "2 cloves garlic". The tool reads the number, the unit and the name, and even guesses the right aisle for each. Q: Is my data saved if I close the tab? A: Yes. Every recipe, meal plan and the items you have ticked off are stored in your browser using localStorage, so they survive a refresh or closing the tab. You can also export everything to a JSON file as a backup, or import it on another device. Q: Does anything get uploaded to a server? A: No. The entire tool runs inside your browser. Your recipes, plan and shopping list never leave your device, there is no account, and it keeps working with no internet connection once the page has loaded. ## AI Tools > Free, private AI utilities — prompt builders and testers, token & cost calculators, model comparisons, output cleaners, RAG and developer helpers, and image-generation prompt builders. Everything runs in your browser; bring your own API key for live model calls. ### Token & Cost Calculators #### LLM API Cost Calculator URL: https://geratools.com/llm-api-cost-calculator Free LLM API cost calculator. Pick a model (GPT, Claude, Gemini and more), enter input and output tokens and your monthly request volume, and see the cost per call and projected monthly spend instantly — all in your browser. How to use: 1. Choose your model: Select the model you are calling — GPT, Claude Opus/Sonnet/Haiku, or Gemini. Each has its own input and output price per million tokens. 2. Enter tokens per request: Type the average input (prompt) tokens and output (completion) tokens for one request. If you only know word counts, roughly 1 word ≈ 1.3 tokens. 3. Add your monthly volume: Enter how many requests you expect per month. The calculator multiplies the per-call cost by your volume to project monthly spend. FAQ: Q: How is the cost per request calculated? A: Cost = (input tokens ÷ 1,000,000 × input price) + (output tokens ÷ 1,000,000 × output price). Providers price input and output tokens separately, and output is usually several times more expensive. Q: Are the prices up to date? A: The model prices are editable presets based on published list prices and are clearly labelled with their verification date. Providers change pricing, so confirm the current rate in your provider's dashboard before budgeting. Q: Is my data sent anywhere? A: No. The calculator runs entirely in your browser. Nothing you enter is uploaded, stored or logged. Q: How do I convert words to tokens? A: As a rough rule, one English word is about 1.3 tokens and 100 tokens is about 75 words. For an exact count, use a model-specific token counter — never assume one provider's tokenizer matches another's. #### Agent Loop Cost Simulator URL: https://geratools.com/agent-loop-cost-simulator Free agent loop cost simulator. See how token cost accumulates across think-act-observe iterations in a ReAct or tool-use agent, compare a typical run against the max_iterations cap, and pick a safe cost ceiling. How to use: 1. Set the per-iteration cost: Enter how many tokens one think-act-observe iteration consumes and the model price per million tokens. 2. Enter the iteration counts: Provide the average number of iterations a task actually takes and the max_iterations safety cap you have configured. 3. Compare typical vs worst case: The simulator shows the cost of a typical run and the worst-case cost if the agent runs to the cap on every task. FAQ: Q: Why do agent loops spiral in cost? A: Each iteration re-sends the growing scratchpad of prior thoughts, actions, and observations as input. Without a cap, a confused agent can loop dozens of times, each iteration more expensive than the last. Q: What does max_iterations protect against? A: It is a hard stop that bounds the worst case. Even if an agent gets stuck, it cannot exceed the cap, which lets you put a firm ceiling on the cost of any single task. Q: How should I choose the cap? A: Set it a few iterations above your typical run so normal tasks finish, but low enough that a stuck task fails fast and cheap. This simulator shows both numbers so you can balance them. Q: Is my data sent anywhere? A: No. The simulator runs entirely in your browser. Nothing you enter is uploaded, stored or logged. #### AI Cost Optimisation Guide URL: https://geratools.com/ai-cost-optimization-guide Interactive guide covering caching, prompt compression, batching, model tiering, and routing strategies — each with a cost-impact estimate applied to your own monthly spend so you can see the savings in pounds, not percentages. How to use: 1. Enter your current monthly AI spend: Type your rough monthly API bill in pounds. The tool uses this to convert every tactic's percentage saving into a real money estimate. 2. Toggle the tactics you can realistically adopt: Switch on the strategies that fit your workload and latency tolerance. Each shows its typical saving range and a short how-to. 3. Read your combined estimate: The tool compounds the selected savings (capped to stay realistic) and shows your projected new bill and total monthly saving. FAQ: Q: Are these savings guaranteed? A: No. The percentages are typical ranges drawn from common production patterns, not promises. Your actual saving depends on your traffic mix, prompt structure, and how aggressively you apply each tactic. Treat the numbers as a planning estimate. Q: Why doesn't selecting everything save 100%? A: Savings compound multiplicatively, not additively, and many tactics overlap — caching and prompt compression both reduce the same input tokens. The tool compounds them and applies a sensible ceiling so the estimate stays believable. Q: Which tactic should I do first? A: For most teams, prompt caching and model tiering give the largest, fastest wins with the least code. Caching repeated context such as system prompts and documents is often the single biggest lever, frequently cutting input costs by half or more. Q: Does cutting cost hurt quality? A: It can if done carelessly. Model tiering and prompt compression trade a little capability for cost, so always evaluate output quality with your own test set before rolling a change to production traffic. Q: Is my spend figure sent anywhere? A: No. Everything runs in your browser. Nothing you type is uploaded or stored. #### Anthropic vs OpenAI Pricing Timeline URL: https://geratools.com/anthropic-vs-openai-pricing-timeline Compare how Anthropic and OpenAI list prices have evolved for equivalent premium, balanced, and economy model tiers — see the per-million-token history and the current cost delta for your own input/output workload. How to use: 1. Pick a model tier: Choose premium, balanced, or economy to compare equivalent-class models from each provider rather than mismatched names. 2. Set your workload ratio: Optionally enter your typical input and output tokens per call so the current delta reflects your real usage mix. 3. Compare the timeline and delta: Read the per-million-token history for each provider and the current blended cost difference for your workload. FAQ: Q: Are these prices official? A: They are editable estimates based on published list prices at the dates shown and are clearly labelled. Providers change pricing frequently, so confirm the current rate in each provider's dashboard before budgeting. Q: How do you decide which models are equivalent? A: We group by capability tier — premium (flagship reasoning), balanced (mid-tier workhorse), and economy (small fast models) — so you compare like for like rather than by marketing name. Q: Why does the workload ratio change the delta? A: Output tokens cost several times more than input tokens, and the two providers price that gap differently. A reasoning-heavy workload with lots of output can flip which provider is cheaper. Q: Is my data sent anywhere? A: No. Everything runs in your browser. Nothing you enter is uploaded, stored, or logged. Q: Has LLM pricing gone up or down over time? A: Broadly down. Intense competition between providers and efficiency gains have driven repeated price cuts at equivalent tiers, even as new flagship models launch at a premium. #### Characters-to-Tokens Converter URL: https://geratools.com/chars-to-tokens-converter Convert raw character counts into estimated tokens for GPT-4o, Claude, Gemini, and Llama. Includes language modifiers for code, Chinese, Arabic, and emoji-heavy text. Runs entirely in your browser. How to use: 1. Enter the character count: Type the number of characters, or paste text to count automatically. Both modes are supported. 2. Pick the content/language: Choose English, code, Chinese/Japanese, Arabic, or emoji-heavy. Each splits into tokens at a very different rate. 3. Read the per-model estimate: See the estimated token count for each major model, using its calibration ratio adjusted by the language modifier. FAQ: Q: How many characters are in a token? A: For English, roughly 4 characters per token. But this varies wildly by content — Chinese can be close to 1 character per token, and emoji can be 2 or more tokens each. Q: Why is non-English text so much more expensive? A: LLM tokenizers are trained mostly on English, so other scripts fragment into many small tokens. Chinese, Arabic, and emoji can cost several times more tokens per character than English prose. Q: Why include a code modifier? A: Source code is dense with symbols and indentation that each become separate tokens, so it produces more tokens per character than ordinary prose. Q: Is this exact? A: It is a calibrated estimate, typically within 5-10% for English and somewhat looser for non-Latin scripts. For exact counts, use the model's own tokenizer. #### Claude Token Counter URL: https://geratools.com/claude-token-counter Estimate token counts for Claude Opus, Sonnet, and Haiku using Anthropic's tokenization characteristics. Paste plain text or a multi-turn conversation JSON and get a per-message breakdown plus cost projection, fully client-side. How to use: 1. Choose your model: Select Claude Opus, Sonnet, or Haiku to apply the right pricing for the cost estimate. 2. Paste text or conversation JSON: Drop plain text, or paste an array of message objects with role and content fields to get a per-message breakdown. 3. Read the breakdown: See total tokens, per-message tokens, the percentage of the 200K context window used, and the projected input cost. FAQ: Q: How does Claude's tokenizer differ from GPT's? A: Claude uses its own byte-pair vocabulary that differs from OpenAI's tiktoken. In practice Claude tends to use slightly more tokens than GPT-4o for the same English text — roughly 3.6-3.8 characters per token — which is why counts won't match a GPT counter exactly. Q: Can I paste a full conversation? A: Yes. Paste a JSON array of messages like [{"role":"user","content":"…"}]. The tool counts each message separately and adds a small per-message overhead to approximate the role/structure tokens the API adds. Q: How accurate is the estimate? A: It is a heuristic based on Claude's measured average characters-per-token ratio, not the official tokenizer. For English prose it is usually within 5-10%. For an exact count, call Anthropic's count_tokens endpoint. Q: Is anything sent to Anthropic? A: No. Everything runs in your browser. Nothing you paste is uploaded, stored, or logged. #### Cross-Lingual Token Cost Comparison URL: https://geratools.com/cross-lingual-token-cost-comparison Free tool showing how LLM token cost rises for non-English languages due to tokenizer inefficiency on non-Latin scripts. Enter an English word count and see per-language token multipliers and cost for 20 languages. Runs in your browser. How to use: 1. Enter your English word count: Type the number of words your typical English request or response contains. This is the baseline the comparison scales from. 2. Pick a model tokenizer and price: Choose the per-million-token price for your model. The same tokenizer behaviour applies across all listed languages. 3. Read the per-language multipliers: Each language shows its estimated token multiplier versus English plus the resulting token count and cost, sorted from cheapest to most expensive. FAQ: Q: Why does the same sentence cost more in some languages? A: LLM tokenizers are trained mostly on English and other Latin-script text, so they encode those efficiently. Non-Latin scripts like Chinese, Japanese, Hindi, Thai and Arabic often split into many more tokens for the same meaning, sometimes one token per character or byte, inflating both cost and context usage. Q: Are these multipliers exact? A: No. They are realistic averages derived from published tokenizer studies for byte-pair-encoding tokenizers such as OpenAI's cl100k/o200k. Actual ratios vary by content, model and tokenizer version, so treat them as planning estimates rather than billing figures. Q: Does this affect the context window too? A: Yes. Because token counts inflate for these languages, the same document consumes more of the context window. A prompt that fits comfortably in English may overflow when translated into a high-multiplier language. Q: How can I reduce non-English token cost? A: Use a model with a newer, more multilingual tokenizer (o200k-based tokenizers are more efficient than older ones), cache repeated system prompts, and avoid round-tripping content through English when you can prompt natively in the target language. Q: Does output cost scale the same way? A: The token multiplier applies to both input and output text in that language. Since output tokens are usually priced higher, the cost penalty for verbose non-Latin scripts is felt most strongly on generated responses. #### CSV / Tabular Data Token Estimator URL: https://geratools.com/csv-to-tokens-estimator Paste or upload CSV data and see the estimated token count for four representation strategies — raw CSV, JSON, markdown table, and key-value — to find the most token-efficient format for your LLM prompt. Runs entirely in your browser. How to use: 1. Add your CSV: Paste CSV text directly or upload a .csv file. The first row is treated as the header. 2. Choose how many rows to include: Cap the number of data rows to estimate, so you can size a prompt that only sends a relevant slice of a large file. 3. Compare the formats: See the estimated token count for raw CSV, JSON, markdown table, and key-value formats side by side, and pick the cheapest representation for your model. FAQ: Q: Which format uses the fewest tokens? A: Raw CSV is almost always the most token-efficient because it states each column header once and uses single-character delimiters. JSON repeats every key on every row, often costing two to four times more tokens for the same data. Q: How accurate is the token estimate? A: It uses a character-per-token heuristic (~4 characters per token for English-like text) which is close for most tabular data but not exact. For billing-grade numbers, run the chosen representation through your model's real tokenizer. Q: Why does JSON cost so much more than CSV? A: JSON repeats the full key name in quotes for every field in every row, plus braces, colons, and commas. For a 10-column, 100-row table that is 1,000 repeated keys, which dominates the token count versus CSV's single header line. Q: Is markdown ever worth the extra tokens? A: Markdown tables cost more than CSV but can improve a model's accuracy when columns must be reasoned about positionally. For pure data transfer, CSV is cheaper; for human-readable reasoning, the markdown overhead can pay off. Q: Is my CSV uploaded anywhere? A: No. The file is read and tokenized entirely in your browser. Nothing is sent to a server or stored. #### DALL-E vs Midjourney vs Stable Diffusion Cost Comparison URL: https://geratools.com/dall-e-vs-midjourney-cost Compare per-image and monthly costs for DALL-E 3, Midjourney Pro, Stable Diffusion on Replicate and self-hosted SD for a given monthly generation volume. See which provider is cheapest at your scale and where self-hosting breaks even. How to use: 1. Enter your monthly volume: Type how many images you expect to generate per month across your product or workflow. 2. Pick a resolution tier: Choose standard or HD resolution. Higher resolution costs more per image on the API providers. 3. Compare providers: The tool shows per-image and monthly cost for each provider, including the break-even point where self-hosting beats pay-per-image. FAQ: Q: How is Midjourney cost per image estimated? A: Midjourney bills a flat monthly subscription with a fast-hour allowance rather than per image. This tool divides the subscription by a typical monthly image count to produce an effective per-image cost, which falls as you generate more. Q: When does self-hosting Stable Diffusion pay off? A: Self-hosting trades a fixed GPU rental cost for near-zero marginal cost per image. Below a few thousand images a month, pay-per-image APIs are cheaper; above the break-even volume the tool shows, a dedicated GPU wins. Q: Are these prices exact? A: They are editable estimates based on published list pricing and typical GPU rental rates. Providers change pricing often, so confirm current rates before committing to a provider for a large workload. Q: Is my data sent anywhere? A: No. The comparison runs entirely in your browser. Nothing you enter is uploaded, stored or logged. #### Gemini Token Estimator URL: https://geratools.com/gemini-token-estimator Approximate token counts for Google's Gemini models using character-based heuristics calibrated against the SentencePiece tokenizer. Add image counts for multimodal estimates, see cost projections, and check against the long context window — fully client-side. How to use: 1. Pick a Gemini model: Choose Gemini 1.5 Pro, Flash, or Ultra so the cost estimate and context window match your target model. 2. Paste your text: Drop your prompt or document into the box. The token estimate updates live using Gemini's SentencePiece-calibrated ratio. 3. Add images for multimodal: Enter how many images the request includes. Each image is counted at Gemini's fixed per-image token rate and added to the total. FAQ: Q: How does Gemini count tokens? A: Gemini uses a SentencePiece tokenizer. For English text it averages close to 4 characters per token, similar to GPT models. Images are billed at a fixed token cost per image (about 258 tokens for a standard tile), and audio/video are counted per second. Q: How accurate is this estimator? A: It is a calibrated heuristic, not the exact tokenizer. For English prose it is typically within 5-10% of Google's count_tokens result. For code, non-Latin scripts, or mixed media, verify with the official API. Q: How are images counted? A: Gemini charges roughly 258 tokens per image tile for standard-resolution images. This tool multiplies your image count by that fixed rate and adds it to the text token estimate. Q: Is my text sent to Google? A: No. The estimate runs entirely in your browser. Nothing you paste or enter is uploaded, stored, or logged. #### Inference Cost vs Quality Frontier Explorer URL: https://geratools.com/inference-cost-vs-quality-frontier Interactive plot of major LLMs with cost per 1M tokens on one axis and a benchmark quality score on the other, with Pareto-optimal models highlighted so the best value-for-quality choices are visually obvious. Runs in your browser. How to use: 1. Choose a quality metric: Pick MMLU, HumanEval, or MT-Bench so the quality axis reflects the capability that matters for your task. 2. Set a cost cap: Optionally cap the cost per 1M tokens to drop models outside your budget from the plot. 3. Read the frontier: Models on the Pareto frontier are highlighted — these give the most quality for their cost. Anything below the frontier is dominated by a cheaper or better model. FAQ: Q: What does the Pareto frontier mean here? A: A model is on the frontier if no other model is both cheaper and higher quality. Frontier models represent the best available trade-offs; a model off the frontier is "dominated" because you could get equal or better quality for the same or less money. Q: Which quality metric should I use? A: Match it to your task. MMLU reflects broad knowledge and reasoning, HumanEval measures coding ability, and MT-Bench captures conversational quality. A model that tops one metric may sit mid-pack on another, so pick the one that mirrors your workload. Q: Should I always pick a frontier model? A: Usually yes — off-frontier models are strictly worse value. Among frontier models, pick the cheapest one that clears your minimum quality bar; paying for more quality than you need is wasted budget. Q: Are the benchmark scores exact? A: They are approximate published benchmark figures used as editable presets. Benchmarks vary by prompt and version and can be gamed, so treat them as a guide, not gospel, and validate on your own task. Q: Is anything sent to a server? A: No. The plot and frontier are computed in your browser from a built-in table. Nothing is uploaded. #### Open-Source Model Hosting Cost Calculator URL: https://geratools.com/open-source-model-hosting-calculator Free self-hosting cost calculator for open-source LLMs. Enter model size, cloud GPU instance, utilization and daily volume to see the all-in monthly cost — GPU rental, networking, storage and operational overhead — plus a GPU memory fit check. How to use: 1. Enter the model size: Type the parameter count in billions. The tool estimates the GPU memory needed as roughly two bytes per parameter (fp16) plus headroom for the KV cache and activations. 2. Pick a cloud GPU instance: Select an AWS, GCP, Azure or Lambda instance. Each preset carries an hourly on-demand price and total GPU memory, used to check whether the model fits. 3. Add utilization and volume: Enter your average utilization and daily request volume, plus an operational overhead percentage. The result is an all-in monthly cost and an effective cost per thousand requests. FAQ: Q: Why is self-hosting often more expensive than an API? A: GPU instances bill by the hour whether or not you serve traffic. At low or spiky utilization you pay for idle hardware, which is why managed APIs that bill per token usually win until you reach high, steady volume. This tool shows the idle-time waste directly. Q: How much GPU memory does a model need? A: A rough rule is two bytes per parameter at fp16, so a 70B model needs about 140GB just for weights, plus roughly 20% more for the KV cache and activations. Quantizing to int8 or int4 roughly halves or quarters that, letting models fit on smaller GPUs. Q: What is operational overhead? A: Self-hosting is not just GPU rental. You need on-call coverage, security patching, autoscaling, monitoring and incident response. The overhead percentage approximates that engineering cost as a fraction of the raw hardware spend. Q: When does self-hosting actually pay off? A: When utilization is high and steady. If a single GPU is busy most of the day serving real traffic, the per-request cost can undercut API pricing. The break-even depends heavily on your volume, the model size and how much idle time you can eliminate with batching. Q: Is my data sent anywhere? A: No. The calculator runs entirely in your browser. Nothing you enter is uploaded, stored or logged. #### Output Token Estimator URL: https://geratools.com/output-token-estimator Estimate the expected output token range for a prompt based on task type and input length, then see the per-call cost impact across common models so you can budget completions before you send them. How to use: 1. Paste your prompt: Drop in the prompt text. The tool approximates its input token count from character length. 2. Pick the task type: Choose summarization, translation, QA, or open-ended generation, since each produces a very different output-to-input ratio. 3. Read the estimate and cost: See an expected output token range and the per-call output cost for a selected model so you can budget before sending. FAQ: Q: How does it estimate output tokens? A: It approximates input tokens from text length, then applies a task-specific ratio — summarization shrinks output, translation stays close to one-to-one, and open-ended generation expands well beyond the input. The result is a low-to-high range, not an exact count. Q: Why a range instead of one number? A: Output length is inherently variable; the same prompt can produce a short or long answer. A range sets realistic budget bounds rather than implying false precision. Q: How is the token count approximated? A: It uses the common rule of thumb of roughly four characters per token for English text. That is close enough for budgeting, but real tokenization varies by model and language, so treat it as an estimate. Q: Are the prices current? A: The model prices are illustrative output-token rates for planning. Always confirm against the provider's current pricing page before relying on a number for billing. Q: Does it send my prompt anywhere? A: No. The estimate is computed entirely in your browser with no API calls, so you can paste private prompts safely and pay nothing to estimate. #### PDF-to-Tokens Estimator URL: https://geratools.com/pdf-to-token-estimator Estimate the token count of a PDF from its extracted text or page count, so you can decide whether to summarize, chunk, or send it straight to a long-context model — and see the cost first. Runs entirely in your browser. How to use: 1. Paste the PDF's text: Copy the text from your PDF (or open it and select all) and paste it in, or enter the page count for a quick estimate. 2. Choose a model context window: Pick the model you plan to use so the tool can show whether the document fits in one call. 3. Decide your strategy: Read the token count, cost, and context-fit indicator, then choose to send directly, chunk, or summarize first. FAQ: Q: Why paste text instead of uploading the PDF directly? A: Reliable in-browser PDF parsing needs a heavy library, and scanned PDFs contain images rather than text. Pasting the extracted text (or using the page-count estimate) gives an accurate, private token count without uploading your document anywhere. Q: How does the page-count estimate work? A: A typical text-dense page holds roughly 500 words, and English averages about 1.33 tokens per word, so the tool estimates around 650 to 750 tokens per page. Adjust the words-per-page setting if your document is sparse (slides) or dense (legal text). Q: Should I send a big PDF to a long-context model directly? A: Sometimes. Long-context models bill for every token in the window on every call, so repeatedly sending a large PDF is expensive. If you query the same document many times, summarizing or chunking with retrieval is usually far cheaper. Q: Is my document sent anywhere? A: No. All estimation runs locally in your browser. Pasted text and counts never leave the page. #### Prompt Prefill Token Cost Calculator URL: https://geratools.com/prefill-attack-token-cost Free response prefill cost calculator. Prefilling the assistant turn (JSON braces, headers, a partial answer) means the model generates fewer output tokens. Enter your prefill size and request volume to see daily and monthly savings. How to use: 1. Choose the model: Output tokens dominate prefill savings, so pick the model whose generation price applies. Output is usually several times more expensive than input. 2. Enter your prefill: Type how many tokens of assistant prefix you supply (for example an opening JSON brace, a fixed header, or a partial answer) and how many tokens the model would have generated to produce that same prefix on its own. 3. Add your request volume: Enter requests per day. The tool computes the output tokens you avoid generating and the resulting per-request, daily and monthly savings. FAQ: Q: What is response prefilling? A: Prefilling means you start the assistant's reply yourself by providing the first tokens of its response. The model then continues from there. Anthropic's API supports this by ending the messages array with an assistant role; some other providers offer similar partial-completion features. Q: How does prefilling save money? A: You are not billed for output you supply — only for tokens the model generates. If the model would otherwise spend 60 tokens producing a fixed preamble or JSON scaffold, prefilling that text removes those 60 generated output tokens from every request. Q: Does prefilling do more than save tokens? A: Yes. It also constrains the output format. Prefilling an opening brace forces the model straight into JSON, and prefilling a header skips chatty preambles. That improves reliability of structured output as well as cutting cost. Q: Why enter two different token numbers? A: The prefill field is what you supply; the unprefilled field is what the model would have generated to reproduce that prefix. They differ when your prefill is more compact than the model's natural verbose version. Savings are based on the generated tokens you avoid. Q: Is my data sent anywhere? A: No. The calculator runs entirely in your browser. Nothing you enter is uploaded, stored or logged. #### Prompt Token Length Analyzer URL: https://geratools.com/prompt-length-analyzer Free Stable Diffusion prompt length analyzer. Estimates the CLIP tokens in your prompt and warns when you pass the 75-token chunk limit (150 for extended models), shows which tokens overflow into the next chunk, and suggests moving important words earlier. How to use: 1. Paste your prompt: Drop your full Stable Diffusion prompt into the box. Commas, weights and parentheses are all counted the way CLIP would roughly see them. 2. Read the token estimate: See the estimated CLIP token count and how it compares to the 75-token chunk limit (or 150 for extended models). 3. Fix overflow: If you're over, move your most important descriptors to the front and trim filler words, since tokens early in the prompt carry more weight. FAQ: Q: Why is there a 75-token limit? A: CLIP, the text encoder used by Stable Diffusion 1.x and SDXL, processes text in fixed chunks of 77 tokens — 75 usable plus a start and end token. Anything beyond the first chunk is handled in a separate pass that's stitched together, which weakens how strongly later tokens influence the image. Q: Is this an exact token count? A: It's a close estimate, not the exact CLIP BPE count. The real CLIP tokenizer uses byte-pair encoding with a fixed vocabulary, which can't run fully in the browser without shipping a large vocab file. This analyzer approximates it well enough to tell you whether you're comfortably under, near, or over the limit. Q: What does "extended" mode mean? A: Many WebUIs automatically split long prompts into multiple 75-token chunks and blend them, effectively giving you 150 or more tokens. The 150 mode reflects that, but remember tokens past the first chunk influence the image less, so front-load what matters most. Q: Does word order matter? A: Yes. Earlier tokens generally have more influence on the result, and tokens that overflow into a later chunk have the least. Put your subject and most important descriptors first, and push style and minor details toward the end. #### Prompt Token Budget Planner URL: https://geratools.com/prompt-token-budget-planner Enter your model's context window and desired output length, then see exactly how many tokens remain for your system prompt and retrieved context, with a visual budget bar and overflow warnings. How to use: 1. Set your context window: Pick a preset model or enter a custom context window size in tokens — for example 128,000 for GPT-4o or 200,000 for Claude. 2. Reserve your output: Enter how many tokens you want the model to generate. This is subtracted first because the reply has to fit inside the same window. 3. Plan the input split: Enter your system prompt size; the planner shows the remaining budget for user context and retrieved documents, and warns if you overflow. FAQ: Q: Does the output count toward the context window? A: Yes. For most models the context window covers input plus output combined, so reserving output tokens reduces what's left for your prompt. A few models bill output against a separate cap — check your provider's docs. Q: How do I know my system prompt's token size? A: Use a token counter to measure it, then enter that number here. A rough guide is one token per three-quarters of an English word. Q: What happens if I overflow? A: If input plus reserved output exceeds the window, the API will reject the request or silently truncate. The planner turns the bar red and tells you how many tokens to cut. Q: Should I leave a safety margin? A: Yes. Token estimates aren't exact and chat templates add overhead, so leaving 5-10% headroom avoids surprise truncation in production. #### RAG Context Budget Calculator URL: https://geratools.com/rag-context-budget Enter your chunk size, overlap, system prompt length, and target model to see how many retrieved chunks fit in the context window while leaving room for the user question and completion. How to use: 1. Set your token budget: Pick your target model so the calculator knows the total context window, then enter how many tokens your system prompt, user query, and completion reserve consume. 2. Describe your chunks: Enter the chunk size in tokens and the overlap size. Overlap is counted as part of each chunk because it occupies real context space when chunks are retrieved. 3. Read the chunk budget: The calculator subtracts your fixed costs from the context window and divides the remainder by the effective chunk size to show how many chunks you can safely retrieve. FAQ: Q: Why does overlap reduce how many chunks fit? A: Overlap duplicates tokens between adjacent chunks. When several overlapping chunks are retrieved together, those duplicated tokens still occupy context, so a larger overlap means each chunk costs more space and fewer chunks fit. Q: Should I leave room for the completion? A: Yes. The context window is shared between the prompt and the model's output. If you fill the entire window with chunks, the model has no room to answer, so always reserve tokens for the completion. Q: How accurate is the chunk count? A: It is a planning estimate. Real chunk sizes vary because tokenizers split text unevenly, so treat the number as a safe upper bound and test with your actual documents. Q: Is my data uploaded anywhere? A: No. The calculator runs entirely in your browser. Nothing you type is sent to a server, stored, or logged. #### Special Token Decoder URL: https://geratools.com/special-token-decoder Detect and explain special control tokens like <|im_start|>, <|endoftext|>, BOS, EOS, and [INST] in your prompt or chat JSON. Shows which tokens come from the model's chat template, what each one does, and the hidden token overhead they add. Runs in your browser. How to use: 1. Paste your prompt or chat JSON: Drop in raw text, a ChatML string, or an OpenAI-style messages array. 2. Choose the model family: Pick GPT/ChatML, Llama, Mistral, or Gemini so the right special-token set is recognized. 3. Read the breakdown: Each detected special token is listed with its meaning, source, and estimated token cost. FAQ: Q: What is a special token? A: A special token is a reserved symbol the model treats as structure rather than literal text — markers like <|im_start|> (begin a chat turn), <|endoftext|> (document boundary), BOS/EOS (sequence start/end), and [INST] (Llama instruction wrapper). They steer how the model interprets a sequence and are usually added automatically by the chat template. Q: Should I put special tokens in my own text? A: Almost never. If you type <|im_start|> into a user message, a model may interpret it as a real control token and break formatting or open an injection vector. Let the API's chat template insert them; this tool flags any you have accidentally included. Q: Why do different models use different tokens? A: Each model family ships its own chat template. OpenAI models use ChatML (<|im_start|>role ... <|im_end|>), Llama uses [INST]...[/INST] and special header tokens, Mistral uses a similar instruction wrapper, and Gemini uses its own turn markers. Sending one family's tokens to another model does nothing useful. Q: Do special tokens cost money? A: Yes — each one is a token you are billed for, and the chat template can add several per message (role markers, turn delimiters, BOS/EOS). For short, high-volume messages this overhead is a real fraction of cost, which the companion chat-template overhead analyzer quantifies. Q: Is my input uploaded? A: No. Detection runs entirely in your browser with pattern matching. Nothing you paste is transmitted. #### Tiktoken Browser Tool URL: https://geratools.com/tiktoken-browser Tokenize any text in the browser using the regex pre-tokenization and byte-level rules behind OpenAI's cl100k_base and o200k_base encodings. Shows token count, per-token segments, byte-pair fragments, and special-token detection. Nothing is uploaded. How to use: 1. Paste your text: Type or paste any text or prompt into the input box. 2. Choose the encoding: Pick cl100k_base (GPT-3.5 / GPT-4) or o200k_base (GPT-4o / o-series) to match your model. 3. Read the breakdown: See the token count, the individual token segments with their byte-pair fragments, and any special tokens detected. FAQ: Q: Is this the exact same as OpenAI's tiktoken? A: It implements the same regex pre-tokenization and byte-level pre-processing that cl100k_base and o200k_base use, which reproduces token boundaries and counts very closely. Because the full merge tables ship as megabytes of binary, the final count is a high-accuracy estimate rather than a byte-identical match to the server-side tokenizer. Q: What is the difference between cl100k_base and o200k_base? A: cl100k_base is the encoding used by GPT-3.5-turbo and GPT-4, with a vocabulary of about 100k tokens. o200k_base is the larger ~200k-token vocabulary used by GPT-4o and the o-series, which packs more text per token — especially for code and non-English languages — so the same text usually costs slightly fewer tokens. Q: Why do whitespace and capitalization change the token count? A: GPT tokenizers attach leading spaces to words, so " token" and "token" are different tokens. Capitalization and punctuation also split differently. This is why reformatting a prompt can quietly change its cost. Q: Are special tokens counted? A: The tool flags special tokens like <|endoftext|> if it detects them in your text and notes that they are reserved control tokens. In real API calls the chat template adds its own role and delimiter tokens on top of your visible text. Q: Is my text sent anywhere? A: No. All tokenization runs locally in your browser using JavaScript. Nothing you type is uploaded, logged, or stored. #### GitHub Repo Token Estimator URL: https://geratools.com/token-count-for-github-repo Enter a public GitHub repo URL to fetch its file tree and estimate total token count by file type, helping you decide if the codebase fits in a long-context model or needs chunking before you pay for inference. How to use: 1. Paste a public repo URL: Enter a GitHub repository URL such as https://github.com/owner/name. The tool reads the default branch file tree via the public GitHub API. 2. Filter by file extension: Optionally restrict to extensions like .ts,.py,.md so vendored assets and binaries do not inflate the estimate. 3. Read the verdict: The tool sums estimated tokens by file type and tells you whether the repo fits in your chosen context window or needs chunking. FAQ: Q: How is the token count estimated? A: The GitHub tree API returns each file's byte size. The tool converts bytes to tokens using a code-aware ratio of roughly 3.5 characters per token. This is an estimate within a few percent, not a tokenizer-exact count. Q: Does it read the file contents? A: No. It only reads the file tree and per-file byte sizes, which keeps requests fast and stays well under GitHub's rate limits. Token estimates are derived from sizes, not contents. Q: Why does it only work on public repos? A: It calls the unauthenticated GitHub REST API from your browser, which can only see public repositories. Private repos would require a personal token, which this tool deliberately does not ask for. Q: I hit a rate limit — what now? A: Unauthenticated GitHub requests are capped per IP per hour. Wait a few minutes and retry, or test a smaller repo. The tool surfaces the API error so you know it was a limit and not a bad URL. Q: Why filter by extension? A: Repos often contain lockfiles, images, fonts, and vendored bundles that you would never send to an LLM. Filtering to source extensions gives a realistic estimate of what you would actually feed the model. #### Token Counter (Multi-model) URL: https://geratools.com/token-counter Paste any text and get token estimates across multiple tokenizer families (GPT/tiktoken, Claude, Llama, Mistral) at once, with character and word counts plus quick cost math. Runs fully in your browser. How to use: 1. Paste your text: Drop a prompt, document, or transcript into the text box. Counts update instantly as you type. 2. Read the per-family estimates: See estimated token counts for GPT/tiktoken, Claude, Llama, and Mistral side by side, alongside raw character and word counts. 3. Use it to budget: Compare the estimate against your model's context window or use the per-million pricing in the LLM cost calculator to project spend. FAQ: Q: How accurate is this counter? A: These are heuristic estimates based on each family's average characters-per-token ratio, not the exact tokenizer. For English prose they are typically within 5-10% of the real count; for code or non-Latin scripts the gap can be larger. Q: Why do different models show different counts? A: Each model family uses a different tokenizer (BPE vocabulary). GPT models use tiktoken, Claude uses its own vocabulary, and Llama/Mistral use SentencePiece, so the same text splits into different numbers of tokens. Q: Is my text sent anywhere? A: No. Everything runs in your browser. Nothing you paste is uploaded, stored, or logged. Q: How do tokens relate to words? A: For typical English, one token is about three-quarters of a word, so 100 tokens is roughly 75 words. Punctuation, whitespace, and rare words split into more tokens. #### Token-Inflation Language Checker URL: https://geratools.com/token-inflation-language-checker Free token-inflation checker for LLM prompts. Paste your prompt and instantly flag verbose phrases like "in order to" and "please be aware that", get token-lean replacements, and see how many tokens you save — all in your browser. How to use: 1. Paste your prompt: Drop the prompt or system message you send to the model into the text box. The checker scans it for known filler phrases as you type. 2. Review the flagged phrases: Each verbose phrase is listed with a token-lean replacement and how many times it appears. Empty replacements mean the phrase can be deleted entirely. 3. Copy the leaner rewrite: Use the auto-generated leaner version, or apply the suggestions by hand, and check the estimated token savings before shipping. FAQ: Q: How does the checker estimate token savings? A: It counts words before and after the rewrite and converts to tokens at roughly 1.3 tokens per English word. This is an estimate — the exact saving depends on the model's tokenizer, but the relative reduction is reliable. Q: Why do filler phrases matter for cost? A: System prompts and instructions are billed on every single request. A phrase like "it is important to note that" adds tokens to every call without changing the model's behaviour, so trimming it compounds across thousands of requests. Q: Will removing these phrases hurt prompt quality? A: Usually not. Models respond to clear, direct instructions. Phrases like "kindly", "please be aware that" and "I would like you to" are politeness padding that the model ignores semantically while still charging you for the tokens. Q: Is my prompt sent anywhere? A: No. The checker runs entirely in your browser. Nothing you type is uploaded, stored or logged. Q: Does fewer tokens mean faster responses too? A: Yes. Shorter prompts reduce the input the model must process, which lowers latency as well as cost — a double win at scale. #### Tokens-per-Dollar Leaderboard URL: https://geratools.com/token-per-dollar-leaderboard Ranks major LLMs by how many tokens you get per US dollar, for input-heavy, output-heavy, or balanced workloads, making the most cost-efficient model for your use case obvious at a glance. Runs in your browser. How to use: 1. Pick your workload type: Choose input-heavy, output-heavy, or balanced so the ranking weights input and output prices to match how you actually use the model. 2. Filter by quality tier: Optionally restrict to frontier, mid, or budget tier models so you only compare models that meet your quality bar. 3. Read the leaderboard: Models are ranked by tokens per dollar for your chosen workload, with the most cost-efficient choice at the top. FAQ: Q: Why separate input and output tokens per dollar? A: Providers price input and output differently — output is usually three to five times more expensive. A model that is cheap for input can be expensive for output, so the most efficient model depends on whether your workload reads more than it writes. Q: What does input-heavy versus output-heavy mean? A: Input-heavy workloads send large prompts and get short answers — summarisation, classification, retrieval. Output-heavy workloads send short prompts and generate long answers — content generation, code. Balanced is roughly equal. The leaderboard weights the blended price accordingly. Q: Does cheapest tokens per dollar mean best model? A: No. Value is tokens per dollar at the quality you need. A budget model with huge tokens-per-dollar is useless if it fails your task. Use the quality filter to compare only models that clear your bar, then pick the most efficient one. Q: Are the prices current? A: They are editable presets from published list prices and labelled as estimates. Providers change pricing often, so confirm the current rate before budgeting. Q: Is anything sent to a server? A: No. The ranking is computed in your browser from a built-in price table. Nothing is uploaded. #### Token Trimmer URL: https://geratools.com/token-trimmer Truncates text to an approximate token budget while always cutting at a sentence boundary instead of mid-sentence. Choose a tokenizer profile, see the exact estimated token count before and after, and copy the trimmed result. Runs in your browser. How to use: 1. Paste your text: Drop in the text you need to fit into a token budget. The tool estimates its token count immediately. 2. Set the token budget and tokenizer: Enter the target token count and pick a tokenizer profile so the estimate matches your model family. 3. Copy the trimmed text: The tool cuts at the last sentence boundary that fits under the budget and shows the resulting token count, then you copy it. FAQ: Q: How does it avoid cutting mid-sentence? A: It walks the text sentence by sentence, adding each whole sentence only while the running token estimate stays under your budget, and stops at the last sentence that fits. The result always ends on a complete sentence rather than a truncated fragment. Q: How accurate is the token count? A: It uses a characters-per-token heuristic tuned per tokenizer profile, which is close for typical English prose. For an exact count use the model's own tokenizer, but the trimming and relative counts here are reliable for budgeting. Q: Why offer different tokenizer profiles? A: Different model families pack characters into tokens at slightly different rates. The profiles adjust the characters-per-token ratio so GPT, Claude, and code-heavy text each get a closer estimate. Q: Is my text uploaded? A: No. Tokenization estimation and trimming run entirely in your browser, so you can safely trim sensitive prompts or documents. #### Token Visualizer URL: https://geratools.com/token-visualizer Renders each token as a distinct color-coded span so you can see word boundaries, subword splits, and whitespace handling. Approximates the GPT-4o (cl100k_base) tokenizer client-side. How to use: 1. Paste your text: Drop any prompt, document, or code snippet into the box to tokenize it live. 2. Read the colored tokens: Each token is shown as its own colored chip so you can see where words split into subwords and how whitespace attaches. 3. Check the count: Read the total token count and character-per-token ratio to gauge how dense your text is. FAQ: Q: Is this the exact GPT-4o tokenizer? A: It is a close approximation of cl100k_base's byte-pair behaviour, not the exact vocabulary. It reproduces the visible rules — leading-space attachment, splitting on case and digits, and subword breaks — so counts are usually within a few percent of the real tokenizer for English. Q: Why does a leading space belong to the next word? A: GPT tokenizers attach a leading space to the token that follows it, so ' token' is one token, not a space plus a word. The visualizer shows this by including the space inside the colored chip. Q: Why do numbers split into single digits? A: cl100k_base often splits long digit runs into chunks, so 2026 may become two or more tokens. The visualizer mirrors this so you can see why numeric-heavy text costs more tokens than you would expect. Q: Does it handle other languages? A: It handles them, but non-English and CJK text often uses many more tokens per character because the byte-pair vocabulary is English-biased. The colored chips make that overhead obvious. Q: Is my text uploaded? A: No. Tokenization runs entirely in your browser. Nothing you paste leaves the page. #### Translation Token Multiplier Calculator URL: https://geratools.com/translation-token-multiplier Different languages tokenize at very different densities. Enter English text and see the estimated token count and cost multiplier when translating to Spanish, Chinese, Arabic, Hindi, and 20+ other languages under GPT and Claude tokenizers. Runs in your browser. How to use: 1. Paste English text: Enter the source English text you plan to translate. 2. Choose a tokenizer family: Select GPT (cl100k/o200k style) or Claude to use the right token density baseline. 3. Compare languages: The table shows each target language's estimated token count and the multiplier versus the English original. FAQ: Q: Why do some languages cost more tokens than English? A: Tokenizers are trained mostly on English-heavy data, so English packs more characters per token. Languages with different scripts or rarer subword patterns — Arabic, Hindi, Thai, many African languages — fragment into more tokens for the same meaning, sometimes 2-3x English, which directly raises API cost. Q: Isn't Chinese more compact, so cheaper? A: Per character, Chinese is dense, but each Chinese character often costs roughly one token or more under English-centric tokenizers, and a sentence carries fewer characters. In practice modern tokenizers like o200k handle Chinese fairly efficiently, so its multiplier is moderate — the calculator reflects that newer tokenizers narrowed the gap. Q: Are these multipliers exact? A: No. They are empirical averages of token-per-character ratios observed across multilingual corpora, applied to your character count. Real text varies with domain, named entities, and formatting, so treat the output as a budgeting estimate, not a billing figure. Q: How can I reduce multilingual token cost? A: Use a newer tokenizer (o200k_base is friendlier to non-English than cl100k_base), avoid unnecessary repetition, and for very high-volume non-Latin-script workloads consider models or providers with tokenizers tuned for those languages. Caching repeated system prompts also helps regardless of language. Q: Is my text uploaded? A: No. Character counting and multiplier math run locally in your browser. Nothing you paste is sent anywhere. #### Vector Database Cost Comparison URL: https://geratools.com/vector-db-cost-comparison Input your vector count, embedding dimensions, and monthly query volume to see estimated monthly storage and compute costs for Pinecone, Weaviate Cloud, Qdrant Cloud, and self-hosted pgvector side by side with a feature comparison. How to use: 1. Enter your scale: Provide the number of vectors, their dimension, and your expected monthly query count. 2. Compare the estimates: The tool computes storage size and applies each provider's pricing model to estimate a monthly cost. 3. Weigh features against price: Use the feature column alongside the cost to choose the right managed or self-hosted option. FAQ: Q: How accurate are these estimates? A: They are planning-grade approximations using published list pricing and typical sizing assumptions (4 bytes per float dimension plus index overhead). Real bills vary with replicas, pod sizes, free tiers, and negotiated rates, so treat the numbers as a relative comparison rather than an invoice. Q: How is storage size calculated? A: Raw vector size is vectors × dimensions × 4 bytes (float32), and the tool adds roughly a 30% overhead for the index structure and metadata. That total drives the storage component of each provider's cost. Q: Why is pgvector so much cheaper? A: pgvector runs inside Postgres, so its cost is just the server you already pay for — the estimate uses a flat managed-Postgres instance fee. The trade-off is that you operate it yourself: scaling, backups, and index tuning are on you, unlike the fully managed services. Q: Does it call any pricing API? A: No. The pricing models are built in and evaluated locally in your browser. Update the numbers as providers change their list prices. #### GPU VRAM Requirements Calculator URL: https://geratools.com/vram-requirements-calculator Enter your GPU VRAM and a target model to see whether it fits and at what resolution and batch size. Covers SD 1.5, SDXL, Flux.1 in fp16 and fp8, AnimateDiff, Stable Video Diffusion, and optional ControlNet stacking. How to use: 1. Enter your GPU VRAM: Type how many gigabytes of VRAM your graphics card has. This is the budget every estimate is checked against. 2. Pick a model and resolution: Choose the model you want to run and a target resolution. Higher resolution multiplies the activation memory. 3. Read the fit verdict: The calculator estimates required VRAM, compares it to your card, and tells you whether it fits with headroom or by how much it falls short. FAQ: Q: How much VRAM do I need for SDXL? A: SDXL needs roughly 7GB of VRAM for the model plus activations at 1024px, so an 8GB card runs it but with little headroom, and 12GB is comfortable. Adding a ControlNet pushes the comfortable minimum toward 12GB or more. Q: Can I run Flux.1 on a consumer GPU? A: Flux.1 in fp16 wants around 22GB, which exceeds most consumer cards, but the fp8 build drops to roughly 12GB and runs on a 16GB GPU comfortably or a 12GB card tightly. Quantization is the key to fitting Flux on consumer hardware. Q: Why does resolution change the requirement so much? A: Activation memory scales with pixel area, so doubling each dimension quadruples the activations even though the model weights stay the same. Generating at 1536px instead of 1024px is a large VRAM jump for the same model. Q: What if the calculator says it won't fit? A: Lower the resolution or batch size, switch to an fp8 or quantized checkpoint, or enable offloading (--medvram / --lowvram) and tiled VAE. These reduce peak usage enough to fit most models on smaller cards at the cost of speed. #### Words-to-Tokens Converter URL: https://geratools.com/words-to-tokens-converter Enter a word count and see estimated token counts for GPT-4o, Claude, Gemini, and Llama models. Uses per-model calibration ratios and adjusts for prose, code, or mixed content. Runs entirely in your browser. How to use: 1. Enter your word count: Type the number of words you have, or paste text to count automatically. The converter handles either input. 2. Choose the content type: Pick English prose, code, or mixed. Code packs more tokens per word because of symbols and indentation, so the ratio adjusts. 3. Read the per-model estimate: See estimated tokens for GPT-4o, Claude, Gemini, and Llama, each using its own calibration ratio. FAQ: Q: How many tokens is one word? A: For ordinary English prose, roughly 1 word equals 1.3-1.4 tokens, or about 0.75 words per token. The exact ratio depends on the model's tokenizer and the kind of text. Q: Why does code give a different number? A: Code has lots of symbols, punctuation, and indentation that split into separate tokens, so the same word count produces more tokens than prose. Mixed content sits in between. Q: Why do models differ? A: Each model uses a different tokenizer and vocabulary size. Llama 3's large vocabulary packs more text per token than GPT or Claude, so its token count for the same words is slightly lower. Q: Is this exact? A: It is a calibrated estimate, typically within 5-10% for English. For billing-critical or near-limit decisions, verify with the model's own tokenizer. ### Prompt Builders & Testers #### Acronym Expander Prompt Builder URL: https://geratools.com/acronym-expander-prompt Pick a domain — medical, legal, tech, finance — choose inline annotation or a glossary table, optionally seed known acronyms, and the tool builds a prompt that makes an LLM extract and expand every acronym in a document accurately. How to use: 1. Choose the domain: Select the field your document belongs to so the model uses the right expansions. 2. Pick the output style: Choose inline annotation, a glossary table, or both, and optionally seed acronyms you already know. 3. Copy the prompt: Paste the generated prompt above your document and run it in your LLM to get expanded acronyms. FAQ: Q: Why specify a domain? A: Many acronyms collide across fields — "MS" is multiple sclerosis in medicine but Microsoft in tech. Telling the model the domain dramatically reduces wrong expansions by anchoring it to the right vocabulary. Q: What does inline annotation do versus a glossary table? A: Inline annotation rewrites the text so each acronym is followed by its expansion in parentheses on first use. A glossary table lists every acronym and its expansion separately, leaving the original text untouched. You can request both. Q: Should I seed known acronyms? A: If your document uses non-standard or internal acronyms, seeding them with their correct expansions prevents the model from guessing. The generated prompt instructs it to treat your seed list as authoritative and expand the rest from domain knowledge. Q: How do I stop the model from inventing expansions? A: The prompt instructs the model to mark any acronym it is not confident about as "uncertain" rather than guessing, so you can review those manually. Pair it with a grounding check for high-stakes documents. Q: Does the tool process my document? A: No. It only builds the prompt in your browser. Your document never leaves your machine — you paste it into your own LLM along with the generated instructions. #### Active Prompt Optimizer URL: https://geratools.com/active-prompt-optimizer Sends your prompt to an LLM with instructions to critique and rewrite it toward your goal, then repeats for the number of rounds you choose so each pass builds on the last. Bring your own OpenAI or Anthropic key. How to use: 1. Paste your prompt and goal: Enter the prompt you want to improve and a clear improvement goal, such as more concise, stricter output format, or better edge-case handling. 2. Add your API key and choose rounds: Provide your own OpenAI or Anthropic key and pick how many refinement passes to run. The key stays in your browser. 3. Review each iteration: Each round shows the model's critique and the rewritten prompt. Keep iterating until you approve, then copy the final version. FAQ: Q: How does the optimizer improve a prompt? A: Each round it sends the current prompt to the model with instructions to critique it against your goal and return an improved rewrite. The rewrite becomes the input to the next round, so improvements compound. Q: Where does my API key go? A: It is used only for the direct browser-to-provider request and is never stored or sent to us. You bring your own OpenAI or Anthropic key, and you pay your provider directly for the calls. Q: How many rounds should I run? A: Two or three is usually enough — gains taper off quickly, and too many rounds can over-engineer a prompt or drift from your intent. Watch the critique each round and stop when it stops finding meaningful issues. Q: Why does it cost money to use? A: It makes real LLM calls on your behalf, billed to your provider account. The cost per round is small (typically a fraction of a cent on a mini model) but it is not free because actual inference happens. Q: What makes a good improvement goal? A: Be specific and measurable. "Make it shorter while keeping all constraints," "enforce JSON-only output," or "add fallback behavior for missing data" give the model a target. Vague goals like "make it better" produce vague edits. #### Batch Prompt Runner (BYO Key) URL: https://geratools.com/ai-batch-prompt-runner Paste a CSV of inputs and a prompt template with placeholders, and the tool runs your prompt against each row using your own API key, then downloads the results as a CSV. Throttled, resumable, and fully client-side. How to use: 1. Paste your inputs as CSV: Provide a CSV with a header row. Each column becomes a placeholder you can reference in your prompt template. 2. Write a prompt template: Use double-brace placeholders like {{name}} that match your CSV headers. Each row fills the template before it is sent to the model. 3. Run and download: Add your API key, run the batch (requests are throttled to respect rate limits), watch the live progress, then download a CSV with a new output column. FAQ: Q: How are placeholders matched? A: The first CSV row is treated as headers. Any double-brace token like {{column}} in your template is replaced with that row's value for the matching header. Unmatched tokens are left as-is so you can spot typos. Q: Where does my API key and data go? A: The key and every request go directly from your browser to the provider and are never stored or sent to us. Your CSV is parsed and processed entirely in the page. Q: Won't this hit rate limits? A: Requests are run with a small delay and limited concurrency to stay under typical rate limits. If a row errors, it is recorded in the output with the error text and the batch continues rather than stopping. Q: What does the output look like? A: A CSV with all your original columns plus an added column containing the model's response for each row, ready to download and open in a spreadsheet. Q: How big a batch can I run? A: It runs in your browser, so practical limits are your patience and your provider's rate limits and budget. For very large jobs, split the CSV — and remember every row is a billed API call. #### AI Cover Song Arrangement Guide URL: https://geratools.com/ai-cover-song-prompt-guide Build cover song prompts for Suno and Udio. Describe the original song style, target genre, instrumentation changes, and key or tempo shifts so the AI rearranges a track into a new style cleanly. How to use: 1. Describe the original: Name the original song's genre and feel so the model has a starting reference for what it is rearranging. 2. Set the target style: Choose the genre and mood you want the cover to land in, plus any instrumentation swaps such as acoustic guitar to synth pads. 3. Copy and generate: Paste the assembled style prompt into Suno or Udio's style box, supply your own lyrics, and generate. Suno and Udio cannot reproduce copyrighted melodies, so this drives an original arrangement in the new style. FAQ: Q: Can Suno or Udio copy an existing song exactly? A: No. These tools generate original audio and will not clone a copyrighted recording or melody. This guide helps you describe a style and arrangement so the AI produces a fresh cover-style track rather than a copy. Q: Why describe the original song's style at all? A: Giving the model the source genre and tempo anchors the rearrangement so the new version still feels related. Without it, the AI may drift far from the energy and structure you wanted to reinterpret. Q: How do I change the key or tempo? A: State the target tempo in BPM and the mood you want. Slower tempos and minor keys read as ballad or acoustic covers; faster tempos with a major feel read as upbeat or dance reinterpretations. Q: Do I need to provide lyrics? A: For Suno and Udio you supply your own lyrics in a separate field. The style prompt this tool builds only controls the musical arrangement, instrumentation, and mood of the cover. #### Explainer Video Script Prompt Builder URL: https://geratools.com/ai-explainer-video-script-builder Free explainer video script prompt builder. Enter your product, audience, key message and length to generate a structured AI prompt for a problem-solution-CTA script, plus a narration word budget — all in your browser. How to use: 1. Describe the product and audience: Enter what you are explaining and who it is for so the script hook targets the right pain point. 2. Set the key message and length: Add the one thing the viewer must remember and pick a duration. The tool calculates a matching narration word budget. 3. Copy the prompt and generate: Copy the prompt into your AI tool to produce a two-column visual and voiceover script, then refine the hook and CTA. FAQ: Q: How is the word budget calculated? A: Spoken narration runs at roughly 150 words per minute, so a 60-second video targets about 150 words. The tool scales this to your chosen length so the script does not run long when read aloud. Q: What script structure does it produce? A: The prompt asks for a classic explainer arc — problem, solution, how it works, then a single call to action — laid out as a two-column visual and voiceover script in 5 to 10 second scenes. Q: Why is the first five seconds so important? A: Viewers decide almost immediately whether to keep watching. The prompt forces a hook in the opening five seconds that names the pain your audience feels, which is the biggest driver of completion rate. Q: Is my information sent anywhere? A: No. The builder runs locally in your browser. Your product details and key message are never uploaded or stored. #### Image Prompt Refiner (BYO-key) URL: https://geratools.com/ai-image-prompt-refiner Use your own OpenAI or Anthropic API key to analyze an image-generation prompt and rewrite it with stronger style, lighting, composition, and detail cues. Returns three enhanced variants tuned for your target model. Your key stays in your browser. How to use: 1. Add your API key: Pick OpenAI or Anthropic, choose a model, and paste your own key used only for the direct request to the provider. 2. Describe your image and pick a target: Enter your rough prompt and select the target generator so the rewrite matches its style and syntax. 3. Generate three variants: Run it to get three refined prompt variants with added style, lighting, and composition cues, then copy your favourite. FAQ: Q: Why refine an image prompt? A: Image models respond strongly to explicit cues about style, lighting, lens, composition, and mood. A vague prompt yields generic output; a refined one with concrete descriptors produces sharper, more intentional images. Q: Where does my API key go? A: It stays in your browser tab and is sent directly to OpenAI or Anthropic with the request you trigger. It is never stored, logged, or routed through any Gera server, and refreshing the tab clears it. Q: How are the variants tailored to each generator? A: The tool tells the model which generator you are targeting so it can match conventions — Midjourney parameter flags like --ar and --style, Stable Diffusion comma-separated tag style, or DALL-E natural-language descriptions. Q: Does this generate images? A: No. It only produces refined text prompts. You then paste those prompts into your image generator of choice. This keeps the tool free of image-generation costs and provider lock-in. Q: Who pays for the API calls? A: You do, on your own provider account. Each refine is one real API call billed at your usage rate. The tool itself is free — your only cost is the tokens consumed on your key. #### AnimateDiff Prompt Guide URL: https://geratools.com/animatediff-prompt-guide Interactive guide for AnimateDiff prompt writing — pick a base model and motion type to get motion module and motion LoRA recommendations, plus a prompt-travel schedule template for smooth animated transitions. How to use: 1. Choose your base model: Select SD 1.5 or SDXL. AnimateDiff motion modules are version-specific, so this determines which module and LoRAs are compatible. 2. Pick a motion type: Choose camera movement (pan, zoom, tilt) or subject motion. The guide recommends the matching motion LoRA and strength. 3. Generate a prompt travel schedule: Enter how many keyframe prompts you want and the tool builds a frame-indexed prompt-travel template you can paste into your workflow. FAQ: Q: What is a motion module? A: A motion module is the AnimateDiff component that injects temporal consistency into a frozen image model. It is version-specific — mm_sd_v15_v2 for SD 1.5 and dedicated SDXL beta modules for SDXL. Loading the wrong module for your checkpoint produces flicker or no motion. Q: What are motion LoRAs? A: Motion LoRAs are small add-ons that bias the animation toward a specific camera move — pan left/right, zoom in/out, tilt, or rolling. You stack them on top of the motion module and control intensity with a LoRA weight, typically 0.6 to 1.0. Q: What is prompt travel? A: Prompt travel assigns different prompts to different frame indices, so the animation morphs from one description to another over time. You write a schedule like {0: 'a closed flower', 16: 'a blooming flower'} and AnimateDiff interpolates between them. Q: How do I keep frames consistent? A: Fix the seed, keep the base prompt stable and only vary the travel terms, and use a context length and overlap that match your frame count. A consistent seed plus a single motion module is the biggest lever on coherence. Q: SD 1.5 or SDXL for AnimateDiff? A: SD 1.5 has the most mature motion modules, LoRAs and community workflows, so it is the safer default. SDXL AnimateDiff support exists but the ecosystem is smaller and heavier on VRAM. #### API Key Masker for Prompts URL: https://geratools.com/api-key-masker Scans prompt text for common API key patterns (OpenAI, Anthropic, Google, AWS, Stripe, GitHub and more) and masks or flags them before you accidentally paste a secret into a chat, log, or screenshot. How to use: 1. Paste the text to scan: Drop in the prompt, log line, or message you are about to share. Everything runs locally in your browser. 2. Review flagged secrets: The tool highlights each detected key with its provider type and position so you can confirm it is a real secret, not a false positive. 3. Copy the masked version: Use the masked output for sharing or logging. Keys are replaced with a redacted placeholder that preserves the first and last few characters for traceability. FAQ: Q: Which API key formats does it detect? A: It recognises OpenAI (sk-, sk-proj-), Anthropic (sk-ant-), Google AI (AIza), AWS access keys (AKIA), Stripe (sk_live / pk_live), GitHub tokens (ghp_, github_pat_), Slack (xox), and generic high-entropy bearer tokens. Patterns are based on each provider's published prefix conventions. Q: Is my text uploaded anywhere? A: No. All scanning and masking happens in your browser with JavaScript. The text never leaves your device, which is the whole point of a tool you use precisely because the content may contain secrets. Q: What does the masked output look like? A: Each detected key is replaced with its first four and last four characters joined by a redaction block, for example sk-1234…████…ab12. This keeps the output readable and auditable without exposing the secret. Q: Can it produce false positives? A: Yes, long random-looking strings can match generic token patterns. The tool labels each hit with the matched rule so you can judge it. Provider-prefixed matches (sk-ant-, AKIA, etc.) are high confidence; generic entropy matches are flagged as lower confidence. Q: Should I still rotate a key that leaked? A: Absolutely. Masking text after the fact does not undo a key that was already pasted into an untrusted system. If a real secret was exposed, revoke and rotate it immediately, then use this tool going forward as a pre-send safety check. #### Art Style Prompt Library URL: https://geratools.com/art-style-prompt-library Free art style prompt library for AI image generation. Search dozens of art styles and movements — impressionism, ukiyo-e, art deco, cyberpunk, anime, brutalism and more — and copy curated prompt keywords for Midjourney and Stable Diffusion. How to use: 1. Filter by category: Narrow the library to painting, illustration, modern, digital, decorative or design styles to find the family you want. 2. Search by name or era: Type a movement, technique or period — like baroque, anime or 1960s — to find matching styles instantly. 3. Copy the prompt terms: Each style comes with curated, comma-separated keywords. Click copy and paste them into your image-generation prompt. FAQ: Q: How do art-style keywords change AI image output? A: Naming a recognised style or movement activates the visual patterns the model learned from labelled artwork — brushwork, palette, line quality and composition. Saying "ukiyo-e woodblock print" or "art deco" reshapes the entire look far more than describing the subject alone. Q: Can I mix two art styles in one prompt? A: Yes, and blending is a great way to get original results — for example "art nouveau meets cyberpunk." Keep it to two complementary styles; mixing several conflicting movements often produces a muddy average rather than a clear look. Q: What is the best art style for fantasy concept art? A: "Concept art, painterly digital, cinematic" is the workhorse for fantasy and game art. Pair it with a lighting term and an art movement like romanticism or baroque for added drama. Q: Should I name a specific artist? A: This library uses movement and technique names rather than living artists, which is the more reliable and ethically safer approach. Style descriptors like "expressive swirling brushwork" give you the look of a movement without imitating a specific person. Q: Is anything stored when I copy? A: No. The library runs entirely in your browser and copying uses your local clipboard only. Nothing is uploaded or logged. #### Clipdrop / Stability AI API Guide URL: https://geratools.com/clipdrop-prompt-guide Reference guide and live tester for Stability AI's Clipdrop API endpoints — background removal, cleanup, image upscaling, and reimagine. Shows the exact request structure and runs single-file operations directly from your browser with your own API key. How to use: 1. Add your API key: Paste your Clipdrop or Stability AI key into the password field. It is sent only to clipdrop-api.co from your own browser and never stored. 2. Pick an operation: Choose background removal, cleanup, upscaling, or reimagine. The guide shows which form fields each endpoint requires. 3. Run or copy the cURL: Upload an image to run single-file operations live, or copy the generated cURL command to wire the call into your own backend. FAQ: Q: What can the Clipdrop API do? A: Clipdrop, owned by Stability AI, exposes image-editing endpoints including background removal, object cleanup with a mask, super-resolution upscaling, and reimagine variations. Each is a separate REST endpoint that takes multipart form-data and returns an image. Q: How does authentication work? A: Every request needs an x-api-key header containing your Clipdrop API key. You generate the key in the Clipdrop API dashboard; this tool never sees or stores it beyond sending it to Clipdrop's servers. Q: Why do cleanup and upscaling not run in the browser demo? A: Cleanup needs a second same-size mask image and upscaling needs explicit target dimensions, so they require extra inputs. The guide shows the full cURL structure for those calls so you can build them in your own code. Q: Is my image uploaded anywhere besides Clipdrop? A: No. The live test posts your file directly to clipdrop-api.co. Nothing routes through this page's servers, and the result is returned straight to your browser. #### Comparative Analysis Prompt Builder URL: https://geratools.com/comparative-analysis-prompt Generates a comparison prompt with explicit evaluation dimensions, optional weighting, bias-avoidance instructions, fact-vs-opinion separation, and a structured table or scorecard output format. Assembled locally in your browser. How to use: 1. List the items: Enter the things you want to compare, one per line or comma-separated. 2. Set dimensions and weighting: Optionally add the dimensions to evaluate and choose equal or importance-weighted scoring. 3. Copy the prompt: Copy the generated prompt into your LLM to get a fair, structured comparison with a verdict. FAQ: Q: How does it keep the comparison fair? A: The prompt instructs the model to apply the same standard to every item, mark unknown cells as "unknown" rather than guessing, separate facts from opinion, and watch for recency, popularity, and order biases. Q: What is dimension weighting? A: When you choose importance-weighting, the prompt asks the model to assign each dimension a weight reflecting how much it should matter, then compute a weighted total — so a minor factor cannot swing the verdict like a major one. Q: Why does it ask for a "Best for…" line per item? A: "Best" depends on context. By giving each item a one-line "Best for…" recommendation, the analysis lets different readers self-select rather than forcing a single winner that may not fit their situation. Q: Can the model compare things it does not have data on? A: Only partially. The prompt tells it to mark missing information as unknown instead of inventing it. For current prices or specs, verify the output against primary sources, since model knowledge can be stale. #### Composition Rule Prompt Builder URL: https://geratools.com/composition-rule-builder Free composition prompt builder for AI image generation. Pick a composition rule like rule of thirds, golden ratio, leading lines or Dutch angle, set the subject position and shot type, and copy framing terms for Midjourney and Stable Diffusion. How to use: 1. Choose a composition rule: Select a framing rule such as rule of thirds, golden ratio, centered symmetry or leading lines. A short description explains each one. 2. Set subject position and shot type: Optionally place the subject in the frame and pick a shot type or camera angle like wide, close-up, low or aerial. 3. Copy the terms: The builder combines your choices into a clean prompt snippet you can copy and append to any image-generation prompt. FAQ: Q: Do composition keywords work in AI image generators? A: Yes. Terms like "rule of thirds," "leading lines" and "Dutch angle" come from photography and film, where they are heavily captioned, so models reliably shift framing, subject placement and camera angle when you include them. Q: What is the rule of thirds in a prompt? A: The rule of thirds divides the frame into a 3×3 grid and places the subject on a line or intersection rather than dead center. In a prompt, "rule of thirds composition, subject on intersection point" produces a more naturally balanced, dynamic frame. Q: When should I use a Dutch angle? A: A Dutch angle tilts the horizon to create tension, unease or energy — useful for thrillers, action scenes and dramatic moments. Avoid it for calm or formal subjects, where centered symmetry works better. Q: How do shot types change the image? A: Shot type sets the camera's distance and angle. A wide establishing shot shows the whole environment, a close-up creates intimacy, a low angle makes the subject look powerful, and an aerial top-down view abstracts the scene. Q: Is anything stored when I copy? A: No. The builder runs entirely in your browser and copying uses your local clipboard only. Nothing is uploaded or logged. #### Consistent Character Prompt Sheet URL: https://geratools.com/consistent-character-sheet Free tool that builds a character prompt sheet with locked tokens (name, physical traits, clothing) and variable tokens (pose, expression, setting), so the same character stays consistent across multiple AI image generations. How to use: 1. Lock the identity tokens: Enter the character name and the physical traits, clothing and signature features that must never change between images. These become your locked block. 2. Set the variable tokens: Choose the pose, expression and setting for this specific shot. These change image to image while the locked block keeps the character recognisable. 3. Copy and reuse the locked block: Copy the full prompt for this shot, and paste the locked block verbatim into every other generation. Only edit the variable tokens between renders. FAQ: Q: Why does character consistency break across AI images? A: Image models regenerate everything from scratch each time, so small wording changes drift the face, hair or outfit. The fix is to keep an identical, detailed description of the unchanging traits in every prompt and only vary the scene-specific words. Q: What should go in the locked block versus the variable block? A: Locked tokens are anything that defines who the character is — name, age, face shape, hair, eye colour, build, skin tone, signature clothing and accessories. Variable tokens are anything that should change per shot — pose, camera angle, expression, lighting and setting. Q: Does this work for Midjourney, DALL·E and Stable Diffusion? A: Yes. The locked-token approach is model-agnostic. For even tighter consistency, pair it with model features like Midjourney's --cref / character reference, DALL·E reference images, or a trained LoRA in Stable Diffusion. Q: Is my character description sent anywhere? A: No. The sheet is assembled entirely in your browser from the text you type. Nothing is uploaded, stored or logged. #### Domain Adaptation Prompt Builder URL: https://geratools.com/domain-adaptation-prompt Injects industry-specific terminology, regulatory context, audience assumptions, and output conventions into a generic prompt to produce a domain-adapted version that speaks the vertical's language. How to use: 1. Paste a generic prompt: Start with the plain version of your prompt that has no industry-specific framing. 2. Choose the target domain and audience: Select the vertical, set any regulatory context, and describe who the output is for. 3. Copy the adapted prompt: The builder wraps your prompt with domain terminology, compliance reminders, and the right output conventions. FAQ: Q: What does domain adaptation actually add? A: It prepends and appends framing — the vertical's vocabulary, the audience's expertise level, relevant regulatory or safety constraints, and the output conventions that industry expects. The model then answers in the register and with the cautions that domain requires. Q: Why not just write the prompt for the domain directly? A: You can, but reusing one generic prompt across many verticals is faster and more consistent. This tool lets you keep a single source prompt and stamp it for healthcare, finance, legal, or any vertical on demand. Q: Does the regulatory context guarantee compliance? A: No. It reminds the model to respect named regulations and to flag when professional review is needed. It is not legal or compliance advice, and a qualified human must still review regulated output. Q: Which domains are supported? A: The builder ships presets for common verticals like healthcare, finance, legal, education, and engineering, and lets you type any custom domain so it adapts to niche industries too. Q: Is anything sent to a server? A: No. The prompt is assembled entirely in your browser. Nothing is uploaded or stored. #### Evidence-Based Response Prompt Builder URL: https://geratools.com/evidence-based-prompt Generates prompts that instruct the model to enumerate evidence, classify it by strength (anecdotal, observational study, RCT, meta-analysis), and weigh conclusions accordingly so you get reasoning grounded in graded evidence. How to use: 1. State the research question: Enter the question you want answered. The prompt instructs the model to gather and grade evidence before concluding, not to answer off the cuff. 2. Pick an evidence scale and formats: Choose how evidence should be classified and how citations and the final conclusion should be presented. 3. Copy into your LLM: Paste the generated prompt into ChatGPT, Claude, or Gemini and supply your sources or let the model reason over its own knowledge with the grading discipline applied. FAQ: Q: Why grade evidence instead of just asking for an answer? A: An ungraded answer treats a tweet and a meta-analysis as equally authoritative. Grading forces the model to separate weak signals from strong ones, which surfaces overconfident claims and makes the reasoning auditable. Q: Does this make the model cite real sources? A: It instructs the model to enumerate and label its evidence, but a model can still hallucinate citations. Always verify any specific reference. The value is in the structured reasoning and the explicit strength labels, not blind trust. Q: Which evidence scale should I use? A: Use the clinical or scientific scale for medical and research questions and the general scale for everyday topics. The general scale (anecdote, expert opinion, study, consensus) is easier for the model to apply to non-academic subjects. Q: Is anything sent anywhere? A: No. The builder runs entirely in your browser and only outputs prompt text. Nothing is uploaded or stored. #### Inpainting Mask & Prompt Guide URL: https://geratools.com/inpainting-mask-guide Free inpainting prompt builder and guide for Stable Diffusion and DALL·E. Describe the area you're editing and the change you want, pick your model, and get a tailored prompt plus the right denoising strength and a checklist to avoid seams and ghosting. How to use: 1. Describe the area: Say what currently occupies the region you've masked, so the prompt can reference the surrounding context the edit needs to blend into. 2. Describe the change: State exactly what you want in that area instead — be specific about subject, material and lighting so it matches the rest of the scene. 3. Use the prompt and denoise level: Paste the prompt into your model's inpainting tab and set the suggested denoising strength, then refine in small steps if the edit looks pasted-on. FAQ: Q: What is denoising strength in inpainting? A: Denoising strength controls how much the masked area is changed. Low values (0.2–0.4) make subtle tweaks that stay close to the original; high values (0.7–1.0) regenerate the area almost from scratch. For small fixes use low values; for replacing an object entirely use high values. Q: Why does my inpaint look pasted-on with hard seams? A: Hard seams usually come from too-tight a mask, too-high denoising at the edges, or a prompt that doesn't mention the surrounding lighting and style. Feather the mask, include "seamless blend, matching lighting and style" in the prompt, and consider masking a slightly larger area so the model has context to blend into. Q: Should I prompt the whole image or just the edit? A: Prompt the content you want in the masked region, but include a few words describing the overall scene, lighting and style so the new pixels harmonise. Many UIs offer an "inpaint masked content / original / latent noise" option — "original" or "fill" helps the blend, "latent noise" allows bigger changes. Q: Does this run my image through a server? A: No. This tool only assembles a text prompt and advice in your browser. It does not upload, process or store any image — you run the actual inpainting in your own model or app. #### Jailbreak Phrase Reference Library URL: https://geratools.com/jailbreak-phrase-library A curated, offline reference of documented LLM jailbreak and bypass patterns grouped by technique — role-play, instruction override, token manipulation, hypothetical framing and more — so developers and red-teamers can study and test their own filters without any network calls. How to use: 1. Browse or search the library: Filter the catalogue by technique category or type a keyword to find documented patterns relevant to what you are testing. 2. Read the technique and why it works: Each entry explains the mechanism behind the bypass and the kind of guardrail it targets, so you understand what your filter must defend against. 3. Use the template against your own system: Copy a templated pattern and run it through your own model and filters to verify they hold. Test only systems you own or are authorised to assess. FAQ: Q: Is this library for attacking AI systems? A: No. It is a defensive reference for developers and authorised red-teamers to test the robustness of their own filters and guardrails. The entries describe techniques at a conceptual level so you can build defences, not bypass someone else's system. Q: Why are the entries templated rather than ready payloads? A: The goal is education and self-testing, so entries describe the technique and provide a neutral, fill-in-the-blank template. This is enough to evaluate your own defences without shipping turnkey harmful payloads. Q: Does it call any external service? A: No. The entire catalogue is bundled and runs in your browser with no network calls. Nothing you search or copy is logged or transmitted, which suits security teams working in restricted environments. Q: How should I use this responsibly? A: Only test systems you own or have explicit written authorisation to assess. Use findings to strengthen system prompts, input filters, and output moderation, and follow responsible disclosure if you find a flaw in a third-party product. Q: Will these patterns keep working? A: Model providers continuously patch known bypasses, so any specific phrasing degrades over time. The value here is understanding the categories of attack, which remain stable even as individual phrasings stop working. #### JSON Schema Prompt Builder URL: https://geratools.com/json-output-schema-prompt Paste a JSON schema or a sample object and the tool generates a prompt instruction block that tells the model to output conforming JSON, complete with field-by-field type reminders, required-field rules, and no-extra-prose guardrails. How to use: 1. Paste a schema or sample object: Drop in either a JSON Schema or an example JSON object. The tool reads the field names and types either way. 2. Choose the strictness level: Pick how firm the instructions should be — from a gentle reminder to a strict "no extra keys, no prose" contract that maximises parse reliability. 3. Copy the instruction block: Copy the generated block and append it to your prompt, or use it as a system message. The model now knows the exact shape to return. FAQ: Q: Why not just say "return JSON"? A: Models often add a markdown fence, a preamble, or extra keys when you only ask for JSON. The generated block names every field, restates types, forbids extra keys, and bans prose, which dramatically raises the rate of first-pass parseable output. Q: Does this replace OpenAI's JSON mode or function calling? A: It complements them. Native structured-output features are stronger when available, but they are not on every model or endpoint. A well-formed schema prompt works everywhere and is still useful as the instruction inside a function-calling tool description. Q: What if I only have an example object, not a schema? A: That is fine — paste the example and the tool infers field names and types from it. Inferred types are a best guess, so check the booleans and numbers, but it is usually enough to anchor the model. Q: Will the model always return valid JSON? A: No prompt is 100 percent. Strict mode gets you very close, but you should still parse defensively and retry on failure. The tool maximises the success rate; it does not guarantee it. #### Lighting Style Prompt Library URL: https://geratools.com/lighting-style-library Free lighting prompt library for AI image generation. Browse and search dozens of lighting setups — golden hour, Rembrandt, studio softbox, neon noir, volumetric god rays and more — with copy-ready prompt terms for Midjourney and Stable Diffusion. How to use: 1. Filter by mood: Choose a mood like dramatic, soft, warm or moody to narrow the library to lighting setups that fit the feeling you want. 2. Search by keyword: Type a term such as neon, golden or rim to find matching lighting styles by name, description or prompt terms. 3. Copy the prompt terms: Each lighting style includes a ready-made comma-separated snippet — click copy and paste it into your image prompt. FAQ: Q: How does lighting affect an AI-generated image? A: Lighting is one of the strongest controls in image generation. Terms like "Rembrandt lighting" or "neon noir" change shadow shape, contrast, color and overall mood far more dramatically than most subject keywords, so describing the light is one of the highest-leverage things you can add to a prompt. Q: What is the best lighting for AI portraits? A: Rembrandt lighting, butterfly lighting and soft window light are the most reliable for flattering portraits. Rembrandt gives a classic dramatic look, butterfly is glamorous and even, and window light is soft and natural. Q: How do I get cinematic lighting in Midjourney? A: Combine a directional setup like rim or volumetric lighting with low-key contrast — for example "volumetric lighting, god rays, low key, deep shadows." Adding atmosphere words like fog or haze reinforces the cinematic feel. Q: Can I combine multiple lighting styles? A: You can, but keep it focused. One primary lighting setup plus an optional atmospheric modifier (fog, haze, rim light) usually works best. Stacking several competing lighting terms can produce muddy or inconsistent results. Q: Does copying store anything? A: No. The library runs entirely in your browser and copying uses your local clipboard only. Nothing is uploaded or logged. #### Music Mood to Prompt Descriptor Translator URL: https://geratools.com/music-mood-to-descriptor Input a mood or emotion — nostalgic, tense, euphoric, melancholic — and get AI-music-optimized prompt descriptors for tempo, key, instrumentation, and production style, assembled into a copy-ready Suno/Udio prompt fragment. How to use: 1. Pick a mood: Choose the emotion you're going for, from euphoric to melancholic to tense. Each maps to a coherent musical profile. 2. Set intensity: Slide the intensity to nudge tempo and production toward subtle or extreme versions of the same mood. 3. Copy the descriptor: The translator outputs suggested tempo, key, instrumentation, and production terms, plus a ready prompt fragment to paste into Suno or Udio. FAQ: Q: How do you describe a mood in an AI music prompt? A: Translate the emotion into concrete musical levers — tempo (BPM), key (major vs minor), instrumentation, and production style. "Melancholic" becomes "slow tempo, minor key, sparse piano, reverb" which the model can actually act on. Q: Does major or minor key affect mood? A: Strongly. Major keys tend to read as bright, happy, or triumphant; minor keys read as sad, tense, or mysterious. The translator picks the conventional choice for each mood, which you can override. Q: How does intensity change the output? A: Higher intensity pushes tempo and dynamics toward the extreme of the mood — a euphoric track gets faster and more maximalist, a tense one more dissonant. Lower intensity keeps it understated. Q: Is this just for AI tools? A: It's tuned for AI music prompts, but the descriptors (tempo, key, instrumentation, production) are general musical vocabulary useful for any composition or brief. #### MusicGen Prompt Guide URL: https://geratools.com/musicgen-prompt-guide Guide to Meta MusicGen prompt writing. Covers text conditioning, continuation and melody-conditioning modes, the 30-second duration limit per generation, and a style descriptor vocabulary for genre, instrumentation, and mood. How to use: 1. Write a descriptive text prompt: Describe genre, instrumentation, tempo, and mood as a short comma-separated phrase. MusicGen is text-conditioned and follows concrete musical descriptors. 2. Choose generation or continuation: Use plain generation for a fresh clip, or continuation mode to extend an existing audio segment so longer pieces stay coherent. 3. Set duration within limits: Generate up to about 30 seconds per call. For longer tracks, generate a base clip then continue from its tail in subsequent calls. FAQ: Q: How long can MusicGen generate in one pass? A: MusicGen reliably produces up to about 30 seconds of audio per generation. The model can technically be pushed longer, but coherence degrades, so for longer pieces you chain generations using continuation mode. Q: What is continuation mode? A: Continuation feeds the model an existing audio segment and asks it to keep going in the same style. It is how you build coherent tracks longer than 30 seconds — generate a base clip, then continue from its final seconds repeatedly. Q: What is melody conditioning? A: The melody-conditioned MusicGen variant accepts a reference melody (a hummed or played line) alongside the text prompt. The model then generates accompaniment in your described style while following that melodic contour, which is useful for arranging a tune you already have. Q: Does MusicGen understand BPM and key? A: It responds well to tempo cues like "120 BPM" or "slow" and to mood-implied keys ("melancholic", "uplifting"), but it does not take an explicit musical-key parameter. Describe the feel rather than naming a specific key signature. #### NovelAI Diffusion Prompt Guide URL: https://geratools.com/nai-diffusion-guide A complete guide to NovelAI Diffusion V3 prompting — danbooru tag vocabulary, the curly-brace and bracket weighting syntax, quality booster tags, undesired-content negatives, and sampler and step recommendations. How to use: 1. Choose your goal and quality: Pick the kind of image you want and the quality booster set; the guide assembles the right opening tags. 2. Add a weighted tag: Enter a tag and a weight to see NAI's exact curly-brace or bracket emphasis syntax. 3. Copy prompt and settings: Copy the assembled positive prompt and apply the recommended sampler and step settings. FAQ: Q: How does NovelAI's tag weighting syntax work? A: NAI uses curly braces to increase a tag's strength and square brackets to decrease it. Each pair of braces multiplies the effect by about 1.05, so {{tag}} is stronger than {tag}, and [tag] weakens it. This differs from the parenthesis-with-number syntax used by AUTOMATIC1111. Q: What quality tags should I use with NAI Diffusion V3? A: V3 responds well to its own booster set, typically best quality, amazing quality, very aesthetic, and absurdres placed at the front. NAI also offers Quality Tags and Undesired Content presets in its UI that prepend these automatically. Q: What sampler and steps work best for NAI V3? A: Euler and Euler Ancestral are reliable defaults, with DPM++ 2M and DPM++ SDE also popular. Around 28 steps is a strong sweet spot; going much higher rarely improves V3 output and just costs more Anlas. Q: What is the Undesired Content field? A: It is NovelAI's name for the negative prompt — tags you want the model to avoid. NAI provides preset levels (Light, Heavy) that fill in common negatives like lowres, bad anatomy, and worst quality, and you can add your own on top. #### Outpainting Extension Prompt Guide URL: https://geratools.com/outpainting-prompt-guide Free outpainting prompt builder and guide for Stable Diffusion and DALL·E. Pick the direction you're extending, describe the scene, choose your model, and get a prompt plus denoising and prompt-mirroring strategies that keep the new area consistent with the original. How to use: 1. Choose the direction: Pick which way you're extending the image — left, right, up, down, or all sides. This decides what scene logic the new region must follow. 2. Describe the scene: Describe the whole scene as it should continue, not just the original crop, so the model knows what belongs in the new area. 3. Apply prompt and denoise: Use the generated prompt, set the suggested denoising strength, and extend in modest steps rather than one giant expansion to keep things coherent. FAQ: Q: What's the difference between inpainting and outpainting? A: Inpainting changes a region inside the existing image; outpainting adds new canvas beyond the original edges and fills it. Outpainting is harder to keep coherent because the model has context on only one side of the new area, so direction, overlap and prompt consistency matter more. Q: Why does my extension drift in style or perspective? A: Drift happens when you extend too far in one step or when the prompt doesn't describe the continuing scene. Extend in smaller steps (a quarter or third of the canvas at a time), keep an overlap region with the original, and re-state the same style and lighting words each pass so the model has an anchor. Q: What does prompt mirroring mean? A: Prompt mirroring means keeping your style, lighting and quality descriptors identical across every outpainting pass while only changing the words that describe the new content. Reusing the same stylistic anchor stops the extension from sliding into a different look as you grow the canvas. Q: Is my image uploaded anywhere? A: No. This tool only builds a text prompt and strategy advice in your browser. It does not upload, view or store your image — you perform the actual outpainting in your own model or app. #### Critique-and-Revise Loop Prompt Builder URL: https://geratools.com/output-critique-and-revise-prompt Generates a self-improvement prompt where the model first answers your task, then critiques that answer against a rubric you define, and finally produces a revised, improved version. Configure the rubric, revision depth, and output format. How to use: 1. Enter your task and rubric: Provide the task you want done and the criteria the answer should meet, one per line — accuracy, tone, completeness, format compliance. 2. Choose revision depth and format: Pick a single critique-revise pass or multiple rounds, and the output format you want for the final version. 3. Copy and run the prompt: Paste it into your LLM. It produces a draft, critiques it against your rubric, then returns a revised answer that addresses each weakness. FAQ: Q: How does critique-and-revise improve output quality? A: It separates generation from evaluation. The first pass produces a draft, the critique pass scores it against your rubric and names specific weaknesses, and the revision pass fixes them. Forcing the model to evaluate its own work against explicit criteria catches errors a single pass would ship. Q: Is this the same as the reflexion or self-refine technique? A: Yes, it implements the same idea — generate, reflect, refine — popularized as self-refine and reflexion. The key is a concrete rubric so the critique is grounded rather than a vague "looks fine." Q: How many revision rounds should I use? A: One critique-revise pass captures most of the gain. Two rounds can help on complex tasks, but beyond that improvements taper and the model risks over-editing or drifting from the original intent. Q: Does this tool call an AI? A: No. It builds the multi-stage prompt that you run yourself. It is fully client-side and needs no API key. Q: What makes a good rubric line? A: Each line should be a checkable criterion, like "every claim has a source," "tone is formal," or "output is valid JSON matching the schema." Vague lines like "make it good" produce vague critiques. #### Persona Consistency Checker URL: https://geratools.com/persona-consistency-checker Paste a persona system prompt and a model output, and the tool runs heuristic checks for tone, vocabulary, knowledge boundaries, and stated-value alignment, flagging passages that break character so you can tighten the prompt. How to use: 1. Paste the persona prompt: Add the system prompt that defines your persona — its name, role, tone, vocabulary rules, and any stated values or knowledge limits. 2. Paste a model output: Add a response the model produced while wearing that persona. The longer the sample, the more signal the checks have. 3. Review the flags: The tool scores tone, vocabulary overlap, banned-phrase usage, and meta-references, then lists specific passages that may break character. FAQ: Q: What is persona drift? A: Persona drift is when a model gradually abandons its assigned character — slipping in disallowed phrases, breaking the fourth wall, or shifting tone — over a long conversation. It is one of the most common reliability problems for branded chatbots and roleplay agents. Q: How does this tool detect inconsistency? A: It compares the output against signals extracted from your persona prompt — required and banned vocabulary, a tone keyword profile, and pattern checks for assistant-meta phrases like 'as an AI language model'. It is a heuristic aid, not a guarantee. Q: Can it catch every break in character? A: No. It catches lexical and structural breaks reliably but cannot judge subtle semantic or factual contradictions. Treat low scores as a prompt to read the flagged passages yourself. Q: Is my text sent anywhere? A: No. All analysis runs locally in your browser. Neither the persona prompt nor the output leaves the page. #### Pony Diffusion XL Prompt Guide URL: https://geratools.com/pony-diffusion-guide A guide to prompting Pony Diffusion XL (PDXL) — the required score_9 quality-tag chain, source and rating tags, tag vocabulary, ready-made negative presets, and the CFG and step settings for consistent results across anime, realistic, and furry styles. How to use: 1. Choose your style: Pick anime, realistic, or furry; Pony handles all three and the source tag steers between them. 2. Read the score and source chain: The guide assembles the required score_9 quality chain plus the right source tag for your style. 3. Copy prompt and settings: Copy the prompt prefix and apply the recommended negative preset, CFG, and step settings. FAQ: Q: What is the score_9 chain and why is it required? A: Pony Diffusion was trained with an aesthetic-scoring system, so it expects a descending chain of score tags at the front of the prompt — typically score_9, score_8_up, score_7_up, score_6_up, score_5_up, score_4_up. This chain is the single most important thing for getting clean PDXL output, and omitting it usually produces flat, low-quality images. Q: What does the source tag do? A: Pony groups its training data by source, so tags like source_anime, source_pony, source_furry, and source_cartoon strongly steer the overall style. Adding the right source tag is how you move PDXL between anime, realistic-leaning, and furry aesthetics. Q: What CFG and steps work for Pony Diffusion XL? A: A CFG of about 6–8 and around 25–30 steps with a sampler like Euler Ancestral or DPM++ 2M Karras is a reliable starting point. Pony tolerates a wide range, but very high CFG tends to over-saturate as with most SDXL models. Q: Do I still need a negative prompt with the score chain? A: Yes. A negative score chain (score_4, score_5, score_6) plus standard quality negatives like worst quality, low quality, and bad anatomy meaningfully improves output. The builder includes a ready-made negative preset you can copy alongside the positive prompt. #### Prompt Anonymizer URL: https://geratools.com/prompt-anonymizer Paste a prompt containing real names, emails, companies, or numbers and get a version with consistent synthetic replacements — the same person always maps to the same fake name — so the AI keeps the context without seeing your real data. How to use: 1. Paste your prompt: Drop in the text you want to send to an AI assistant, including any real names, emails, or numbers. 2. Anonymize: The tool detects entities and replaces each with a consistent synthetic stand-in, keeping a mapping so the same real value always maps to the same fake one. 3. Copy and re-identify: Copy the anonymized prompt to send to the AI, then use the mapping to translate the AI's reply back to the real entities. FAQ: Q: How does consistent replacement help? A: If "Jane Doe" appears five times, it becomes the same fake name every time, so the AI can still reason about relationships and references. Random per-occurrence replacement would destroy that context and confuse the model. Q: Does my text get sent anywhere? A: No. Detection and replacement happen entirely in your browser. Nothing is uploaded, logged, or stored, which is the whole point of anonymizing before you paste into an external tool. Q: What does it detect? A: It detects email addresses, phone numbers, full names (capitalized two-word sequences), URLs, IP addresses, credit-card-like numbers, and common company suffixes. It is heuristic, so review the output to catch anything it missed or over-matched. Q: How do I read the AI's answer afterward? A: The tool gives you a mapping of real to synthetic values. After the AI responds, swap the synthetic placeholders back to the real ones using that mapping so the answer makes sense in your real context. Q: Is this enough for regulated data? A: It is a strong privacy hygiene step but not a certified de-identification process. For health, financial, or other regulated data, follow your organization's approved redaction procedures rather than relying on a heuristic tool alone. #### Prompt Complexity Grader URL: https://geratools.com/prompt-complexity-grader Scores your prompt on a 1-10 cognitive load scale based on required reasoning steps, world knowledge, instruction ambiguity, and output complexity, so you can match it to the right model and prompting strategy. How to use: 1. Paste your prompt: Drop the full prompt you plan to send to the model into the text box, including any instructions, context, and constraints. 2. Read the complexity score: The grader returns a 1-10 score plus a breakdown across reasoning steps, world knowledge, ambiguity, and output complexity. 3. Act on the signals: High scores suggest a stronger model or chain-of-thought; low scores can run on a cheaper, faster model with a simple prompt. FAQ: Q: How is the complexity score calculated? A: The tool runs rule-based heuristics over your prompt text — counting reasoning cue words, multi-step indicators, conditional logic, format demands, and knowledge breadth — and blends those signals into a 1-10 score. It is deterministic and runs entirely in your browser. Q: Does a high score mean my prompt is bad? A: No. A high score just means the task is cognitively demanding, which is fine if it is genuinely hard. It is a signal to pick a capable model and consider step-by-step prompting, not a quality judgment. Q: Why does this matter for model selection? A: Simple, low-complexity prompts run reliably on small, cheap models. High-complexity prompts with many reasoning steps benefit from frontier models. Grading first helps you avoid overpaying or under-provisioning. Q: Does it send my prompt anywhere? A: No. All scoring happens locally in JavaScript in your browser. Nothing is uploaded, logged, or stored. Q: Can I lower a prompt's complexity? A: Often yes — split a multi-step task into separate calls, remove conditional branches, fix ambiguous wording, and simplify the required output format. Re-grade after editing to see the effect. #### Prompt Compression ROI Calculator URL: https://geratools.com/prompt-compression-roi Enter original and compressed prompt token counts plus daily call volume to show monthly savings from prompt engineering or compression libraries like LLMLingua. Fully client-side. How to use: 1. Enter token counts: Type your original prompt token count and the compressed token count after trimming or compression. 2. Set volume and price: Enter your daily call volume and the input cost per million tokens for your model. 3. Read the savings: See the compression ratio, tokens saved per call, and projected daily, monthly, and yearly savings. FAQ: Q: What counts as compression here? A: Any reduction in prompt tokens — manual prompt engineering, removing boilerplate, summarizing context, or running a compressor like LLMLingua. The tool only needs the before and after token counts. Q: Does compression hurt quality? A: It can if you cut load-bearing context. Validate on an eval set before deploying aggressive compression. The savings here only matter if accuracy holds, so treat the number as the upside ceiling. Q: Why use input cost per million tokens? A: Compression reduces input (prompt) tokens, which are billed per million. Output cost is unaffected, so this tool focuses on the input rate. Use your model's published input price. Q: Is the saving really linear with volume? A: Yes — every call you make pays for the prompt, so tokens saved per call multiply directly by call volume. That is why even a small per-call saving becomes large at high volume. Q: Is anything uploaded? A: No. You only enter token counts and numbers. Everything is computed in your browser. #### Image Generation Prompt Builder URL: https://geratools.com/prompt-for-image-generation Guides you through subject, style, lighting, composition, camera specs, and negative prompt fields to construct a well-structured image generation prompt formatted for DALL·E, Midjourney, or Stable Diffusion. How to use: 1. Describe the subject and style: Enter the main subject and pick an art style. These two fields carry the most weight in any diffusion model. 2. Add lighting, composition, and camera: Layer in lighting, framing, and optional camera specs to control mood and realism. 3. Pick your model and copy: Choose DALL·E, Midjourney, or Stable Diffusion. The output is formatted with the right syntax (Midjourney flags, SD negative prompt) for that model. FAQ: Q: Why does the output change by model? A: Each model reads prompts differently. Midjourney uses --ar and --no flags and weights commas; Stable Diffusion uses a separate negative prompt; DALL·E prefers a single natural-language sentence. The builder formats your inputs to each model's conventions. Q: Where does the negative prompt go? A: For Stable Diffusion and SDXL it is emitted as a separate "Negative prompt:" line, which is how those models consume it. For Midjourney it is converted to --no flags. DALL·E ignores negative prompts, so it is folded into descriptive phrasing instead. Q: How specific should the subject be? A: Very. "A red fox" is weak; "a red fox curled asleep on moss, frost on its fur" gives the model something concrete to render. Specificity in the subject and style fields does more than any other setting. Q: Is anything uploaded? A: No. The builder runs locally and only outputs text. Nothing is sent to any image model or stored. #### Lesson Plan Prompt Builder URL: https://geratools.com/prompt-for-lesson-plan Configures subject, student level, duration, learning objectives, and assessment type to produce a lesson-plan-generation prompt that covers objectives, materials, activities, differentiation, and assessment. How to use: 1. Enter the subject and level: Specify the topic, the student level, and how long the lesson should run. 2. Add objectives and assessment: List the learning objectives and choose how learning will be assessed. 3. Copy the lesson-plan prompt: The builder produces a prompt that asks the model for a complete, standards-style lesson plan with every section. FAQ: Q: What sections does the generated lesson plan cover? A: The prompt asks the model for learning objectives, prerequisite knowledge, materials, a timed activity sequence, differentiation for varied learners, and an assessment aligned to the objectives — the standard structure teachers expect. Q: Why specify learning objectives up front? A: Objectives anchor the whole plan. When the model knows the measurable outcomes, it can align activities and assessment to them. Without objectives, lesson plans tend to list activities with no clear purpose or way to measure success. Q: Does it support different student levels? A: Yes. You set the level — from early primary through university or professional training — and the prompt instructs the model to calibrate vocabulary, pacing, and complexity accordingly, including differentiation suggestions. Q: What assessment types can I choose? A: Common options like formative check-ins, a quiz, a project or performance task, a written response, or peer assessment. The model then builds an assessment of that type that maps back to the objectives. Q: Is anything uploaded? A: No. The prompt is assembled in your browser and nothing is sent to a server. #### Prompt Version Differ URL: https://geratools.com/prompt-history-differ Compare two prompt iterations with a word-level diff that highlights additions and removals. See precisely what you changed between versions so you can attribute behaviour shifts to specific edits during prompt engineering. How to use: 1. Paste version A: Put your earlier prompt in the first box. This is treated as the baseline you are diffing against. 2. Paste version B: Put the newer prompt in the second box. The tool aligns the two and computes a word-level diff. 3. Read the highlighted changes: Removed words are struck through in red, added words highlighted in green, and unchanged text stays neutral so the edits jump out. FAQ: Q: Why diff at the word level instead of by line? A: Prompts are usually free-flowing paragraphs, not line-structured code, so a line diff would flag whole paragraphs as changed for a one-word edit. Word-level diffing pinpoints the actual change. Q: How does the diff algorithm work? A: It uses a longest-common-subsequence alignment over the word tokens of both versions, then marks tokens unique to A as removed and tokens unique to B as added. It is the same core technique behind standard text diff tools. Q: Can I diff system prompts with formatting? A: Yes. Whitespace and punctuation are tokenised too, so structural changes like added bullet points or section headers show up as additions. Q: Is anything sent to a server? A: No. The entire diff is computed in your browser. Your prompts never leave the page. #### Narrative Consistency Checker URL: https://geratools.com/prompt-narrative-consistency Splits your story into chapters, extracts stated facts about characters such as eye color, age, and relationships, then flags places where a later chapter contradicts an earlier one — all in your browser. How to use: 1. Paste your story: Paste the full text. Separate chapters with a line like "Chapter 1" or a row of dashes so each section is detected. 2. Run the check: The tool scans each chapter for attribute statements about characters — eye color, hair, age, and relationships — and records where each was stated. 3. Review flagged contradictions: Read the list of conflicts, each showing the attribute, the two values, and the chapters they appeared in, then fix them in your draft. FAQ: Q: How does it detect a contradiction without an AI model? A: It uses pattern matching to capture statements like "her eyes were blue" or "he was forty," keyed by character name and attribute. When the same character and attribute later get a different value, it flags the pair with both chapter numbers. Q: Does my manuscript leave my browser? A: No. All parsing and comparison happen locally in JavaScript. Nothing is uploaded, stored, or sent to any server. Q: What kinds of facts does it track? A: Physical attributes such as eye and hair color, stated ages, and simple relationship claims like "his sister" or "her husband." These are the details readers most often catch when they drift. Q: Will it catch every continuity error? A: No tool can. It catches explicit, restated attributes that change. Subtle plot or timeline issues, implied facts, and pronoun-only references will slip past, so use it as a first pass, not a substitute for a careful read. Q: How should I separate chapters? A: Start a new line with "Chapter" and a number, or use a divider line of three or more dashes or asterisks. If no dividers are found the whole text is treated as one section and only within-section conflicts are reported. #### Prompt Optimizer & Critiquer URL: https://geratools.com/prompt-optimizer-critique Submit a prompt with your own OpenAI or Anthropic API key and get a structured critique covering clarity, specificity, format instructions, and edge cases, plus an improved rewrite. Your key stays in your browser. How to use: 1. Paste your prompt: Enter the prompt you want to improve and, optionally, the target task it is meant to accomplish so the critique is grounded in your goal. 2. Add your API key: Pick OpenAI or Anthropic, choose a model, and paste your own API key. The key is used only for the direct request to the provider from your browser. 3. Read the critique and rewrite: The tool returns a structured critique by category plus an improved version. Copy the rewrite, test it, and iterate. FAQ: Q: Is my API key safe? A: The key never leaves your browser except in the direct HTTPS request to OpenAI or Anthropic. It is not stored, logged, or sent to any Gera server. You can revoke the key at your provider at any time. Q: Which model should I use? A: A small, fast model like gpt-4o-mini or claude-3-5-haiku is usually enough for prompt critique and keeps cost low. Use a larger model only if the rewrites feel shallow. Q: Will the rewrite always be better? A: Not guaranteed. The optimizer applies sound prompt-engineering heuristics, but you should always test the rewritten prompt on your real task and compare outputs before adopting it. Q: Why do I need my own key? A: Running on your key keeps the tool free, private, and unlimited — there is no shared quota and your prompts are not pooled with other users. You pay your provider only for the tokens you use. #### Prompt Instruction Priority Ranker URL: https://geratools.com/prompt-priority-ranker LLMs weight instructions by position and explicit priority markers. Enter your instructions and a priority order, and this tool reorders them using primacy and recency, adds explicit weighting cues, and outputs a position-optimized prompt block. How to use: 1. List your instructions: Add each instruction the model must follow, one per line. These are the rules that may compete for the model's attention. 2. Rank them: Drag-free reordering with up/down controls lets you set which instruction matters most. The ranker assumes the top item is highest priority. 3. Copy the optimized block: The tool places the most important rules at the start and end (primacy and recency) and tags each with an explicit weight, then outputs a ready-to-paste block. FAQ: Q: Do LLMs really weight instructions by position? A: Yes. Models show measurable primacy and recency effects — instructions at the very start and very end of a prompt are followed more reliably than those buried in the middle, an effect often called 'lost in the middle'. Explicit priority labels reinforce the ordering further. Q: What is the 'lost in the middle' problem? A: It is the documented tendency of LLMs to attend less to content placed in the middle of a long context, even when it is critical. The fix is to position your most important instructions near the beginning or end and to mark their priority explicitly. Q: Why add explicit priority labels? A: Position helps, but a clear label like 'HIGHEST PRIORITY' or 'if instructions conflict, follow rule 1 first' gives the model an unambiguous tie-breaker. Combining position and labels is more robust than either alone. Q: Does this guarantee the model obeys? A: No. It stacks the odds in your favor using known position and labeling effects, but model behavior is probabilistic. Test the output and iterate. #### Prompt Safety & Content Policy Checker URL: https://geratools.com/prompt-safety-checker Free prompt safety checker that scans your AI image prompt for terms that commonly trigger content policy rejections on DALL·E 3, Midjourney and Stability AI, flags risky words, and suggests safer alternatives — all in your browser. How to use: 1. Paste your prompt: Paste the image prompt you plan to use into the text box. Nothing leaves your browser. 2. Pick the target platform: Choose DALL·E 3, Midjourney or Stability AI. Each has different banned and risky terms, so the check is tuned per platform. 3. Review flags and rewrite: Read the flagged terms and the suggested safer alternatives, then edit your prompt and re-check until it comes back clean. FAQ: Q: Does a clean result guarantee my prompt will be accepted? A: No. This is a heuristic word-and-pattern check, not the actual model filter. Platforms run far more sophisticated multimodal classifiers and update them constantly. A clean result means you have removed the most common obvious triggers, not that acceptance is guaranteed. Q: Why do the platforms flag different words? A: Each provider sets its own content policy. Midjourney blocks gore and many adult terms outright; DALL·E 3 is strict on real public figures, violence and trademarks; Stability AI is comparatively permissive but still restricts illegal and exploitative content. The checker tunes its lists to the platform you select. Q: What kinds of terms get flagged? A: Common triggers include named real people, gore and violence, sexual or nude content, self-harm, hateful or extremist imagery, illegal activity, and trademarked or copyrighted characters and brands. The tool groups flags by category so you can see why each was raised. Q: Is my prompt sent anywhere? A: No. All scanning happens locally in your browser using built-in word lists. Your prompt is never uploaded, stored or logged. #### Prompt Variable Manager URL: https://geratools.com/prompt-variable-manager Detects every {{placeholder}} in a prompt template, builds a live form for each one, and produces the filled final prompt instantly. Turn any reusable prompt into a clean fill-in-the-blanks template — copy the result, all in your browser. How to use: 1. Write your template: Paste a prompt and mark every reusable slot with double braces, like {{topic}} or {{audience}}. 2. Fill the generated form: The tool finds each unique placeholder and creates an input for it. Type a value into each field. 3. Copy the filled prompt: The final prompt updates live as you type. Copy it and paste it into your chat or API call. FAQ: Q: What placeholder syntax is supported? A: Double-brace tokens like {{variable_name}}. Names can contain letters, numbers, underscores, hyphens and spaces. The same placeholder used multiple times shares one input and is filled everywhere at once. Q: What happens to unfilled placeholders? A: Any placeholder you leave blank stays visible as {{name}} in the output and is listed as still unfilled, so you can see at a glance what is missing before you send the prompt. Q: Can I reuse the same variable several times? A: Yes. If {{name}} appears three times in the template, you fill it once and all three occurrences update together. The form only ever shows each unique variable once. Q: Is my template or data sent anywhere? A: No. Detection and filling happen entirely in your browser. Nothing you type is uploaded, logged or stored. #### Regional Prompter Composition Guide URL: https://geratools.com/regional-prompter-guide Build Regional Prompter settings for Automatic1111. Choose how many regions and a layout (columns, rows, or matrix) to get the correct split mode, divide ratio, and a ready-to-paste BREAK-separated prompt template for per-region control. How to use: 1. Choose region count and layout: Pick how many regions you want and whether they split into columns, rows, or a matrix grid. The tool generates the matching divide ratio. 2. Copy the prompt template: Use the BREAK-separated template — each block before a BREAK applies to one region, in reading order. 3. Enable Base and generate: Turn on Use BASE for shared global details like style and lighting, paste the divide ratio and mode into Regional Prompter, then generate. FAQ: Q: What does the Divide Ratio control? A: It defines the relative size of each region. For columns or rows, comma-separated numbers set the proportions (e.g. 1,2 makes the second region twice as wide). For matrix mode, a semicolon separates rows and commas separate columns within each row. Q: How does the BREAK keyword work? A: Regional Prompter splits your prompt at each BREAK. The first block maps to the first region, the second block to the second region, and so on, in the layout's reading order. Keep each block focused on the subject for that region. Q: What is the Base prompt for? A: The Base prompt applies globally across all regions. Put shared elements there — overall style, lighting, color grade — so you don't repeat them in every region block. Per-region blocks then only describe what differs. Q: When should I use matrix layout? A: Matrix mode is for grids — a 2×2 layout of four subjects, or a full-width band over a row of subjects below. Use columns or rows for simpler left-right or top-bottom compositions. #### Role & Persona Prompt Generator URL: https://geratools.com/role-persona-generator Select a domain, task type, expertise level, and tone to generate a rich role-persona prompt with authority framing, constraints, and output guidance. Runs locally — paste the result into ChatGPT, Claude, or Gemini. How to use: 1. Pick a domain and task: Choose the field the model should act as an expert in, then the task type (advise, review, draft, teach, debug). These set the persona and its primary objective. 2. Set expertise and style: Select the expertise level and communication style. Higher expertise adds authority cues; the style controls tone, length, and formatting expectations. 3. Copy and use the prompt: Copy the generated system prompt and paste it into your model's system field, or prepend it to your first message. Replace the bracketed task placeholder with your real request. FAQ: Q: Does role-prompting actually improve answers? A: For many tasks yes — assigning a clear expert role and explicit constraints reduces vague, hedged output and nudges the model toward domain-appropriate vocabulary and structure. It is most useful for advisory, review, and teaching tasks, and less impactful for simple factual lookups. Q: Should I put this in the system prompt or the user message? A: Either works. System prompts are stickier across a conversation and harder to override, so prefer them for personas you want maintained over many turns. For a one-off request, prepending the persona to your user message is fine. Q: Is anything sent to a server? A: No. The generator assembles the prompt entirely in your browser from your selections. Nothing is uploaded, logged, or stored. Q: Can the model still be wrong even with an expert persona? A: Yes. A persona changes framing and tone, not the model's underlying knowledge or its tendency to hallucinate. Always verify domain-critical claims, especially in medicine, law, and finance. #### SD Negative Prompt Library URL: https://geratools.com/sd-negative-prompt-library Free Stable Diffusion negative prompt library. Mix curated presets for portraits, landscapes, anime and photorealism, see exactly which tokens each adds, and copy a clean deduplicated negative prompt — all in your browser. How to use: 1. Pick the presets that match your image: Toggle one or more presets — Universal, Portrait, Landscape, Anime or Photorealism. Each preset lists the exact tokens it contributes. 2. Add your own tokens: Type any extra unwanted elements as comma-separated tokens. They are merged with the presets and deduplicated automatically. 3. Copy the negative prompt: The combined, deduplicated negative prompt updates live. Copy it into the negative prompt box of AUTOMATIC1111, Forge, ComfyUI or your SD UI. FAQ: Q: What is a negative prompt? A: A negative prompt lists things you do not want in the image. Stable Diffusion steers the generation away from those concepts, which is the main tool for removing artifacts, extra limbs and low quality. Q: Can a negative prompt be too long? A: Yes. Very long negative prompts can over-constrain the model and wash out detail. Start with a small Universal set, then add only the tokens that fix problems you actually see. Q: Do these presets work on SDXL? A: They work on both SD 1.5 and SDXL, but SDXL generally needs shorter negatives. If results look flat on SDXL, trim the list to a few core quality tokens. Q: Is anything sent to a server? A: No. The library is fully client-side. Your selections and custom tokens never leave your browser and nothing is generated here. #### Socratic Dialogue Evaluator URL: https://geratools.com/socratic-dialog-evaluator Paste a multi-turn chat log and the tool scores each model turn on logical consistency, reasoning depth, and alignment with prior turns using heuristic rubrics, so you can spot where a conversation drifts or contradicts itself. How to use: 1. Paste the chat log: Drop in the conversation as JSON or as alternating role-tagged lines like user: and assistant:. 2. Run the evaluation: Each assistant turn is scored on reasoning depth, internal consistency, and alignment with earlier turns. 3. Review the per-turn breakdown: Find the turns that drift, contradict, or thin out, and use them to target your follow-up prompts or fine-tuning data. FAQ: Q: How does it score without an AI judge? A: It applies heuristic rubrics over the text — looking for reasoning markers, explanation length, hedging, and lexical overlap with prior turns as a consistency proxy. It is a fast, deterministic first pass, not a substitute for human or LLM-judge review. Q: What input format does it accept? A: Either a JSON array of objects with role and content fields, or plain text with lines tagged user: and assistant:. The parser detects which one you pasted. Q: What does the consistency score mean? A: It estimates how well each assistant turn stays grounded in the conversation by measuring how much of its content connects to earlier turns. Sudden topic jumps or self-contradiction phrases lower the score. Q: Can it detect contradictions? A: It flags surface-level contradiction cues like reversing earlier statements or saying "actually, no" after a confident claim. It cannot verify factual truth, so deep logical contradictions still need human review. Q: Is my conversation uploaded anywhere? A: No. Parsing and scoring happen entirely in your browser. Nothing leaves the page. #### Stable Audio Prompt Guide URL: https://geratools.com/stable-audio-prompt-guide Guide to Stability AI's Stable Audio model. Covers prompt structure, duration specification, music versus sound-effect mode, and quality descriptors so your generated audio matches the length and style you intend. How to use: 1. Choose music or SFX mode: Decide whether you want a musical piece or a discrete sound effect — the prompt vocabulary differs sharply between the two. 2. Set style, mood, and duration: Add genre or sound descriptors, a mood, and the clip length. Stable Audio respects a requested duration up to the model's maximum. 3. Copy and generate: Paste the assembled prompt into Stable Audio's prompt box, set the duration field to match, and generate. FAQ: Q: How long can Stable Audio clips be? A: Stable Audio can generate longer clips than most text-to-audio models — up to roughly three minutes depending on the model version. You set the target duration in the interface, and the prompt should describe an arrangement that fills that length. Q: Should I put the duration in the prompt or the duration field? A: Use the dedicated duration control as the source of truth; the model honors it directly. Mentioning the length in the prompt as well ("looping 30-second bed") helps the model pace the arrangement so it does not feel cut off. Q: What makes a good Stable Audio music prompt? A: Lead with genre and instrumentation, then add BPM, mood, and production descriptors like "clean mix" or "lo-fi tape saturation". Stable Audio responds well to comma-separated descriptive tags rather than full sentences. Q: Can Stable Audio make sound effects, not just music? A: Yes. For SFX, drop musical terms entirely and describe the literal sound, environment, and intensity — for example "heavy rain on a tin roof, distant thunder, 20 seconds". Keep musical and sound-effect vocabulary separate for the cleanest output. #### Table Output Prompt Formatter URL: https://geratools.com/table-prompt-formatter Define columns, sort order, alignment, and output format, and this tool generates a strict instruction block that forces an LLM to return well-formed Markdown, HTML, or CSV tables every time — no stray prose, no broken rows. How to use: 1. Define your columns: List each column name, one per line, in the order you want them to appear. 2. Set sort, alignment, and format: Choose a sort column and direction, per-format alignment, and whether to output Markdown, HTML, or CSV. 3. Copy the instruction block: The tool builds a strict table-output prompt. Paste it before your data so the model returns a clean table only. FAQ: Q: Why do LLMs produce broken tables? A: Models often add a sentence before or after the table, drop the alignment row, or merge cells when text contains pipes. A strict instruction block that names the columns, format, and "no prose" rule removes the ambiguity and makes the output parseable. Q: Which output formats are supported? A: Markdown (pipe tables), HTML (table, thead, tbody markup), and CSV (comma-separated with a header row). Pick the one your downstream tool consumes — Markdown for docs, HTML for web pages, CSV for spreadsheets. Q: How does alignment work in Markdown? A: Markdown encodes alignment in the separator row using colons — :--- for left, :---: for centre, ---: for right. The generated prompt instructs the model to emit the correct colon pattern for each column you mark. Q: Can I force escaping so cells do not break the table? A: Yes. The instruction block tells the model to escape pipe characters in Markdown cells and to wrap CSV values containing commas in quotes, which prevents the most common table-corruption bugs. Q: Does this call an AI model? A: No. It only assembles a reusable prompt in your browser. You paste the prompt plus your data into your own LLM to generate the table. #### TTS Emotion & Tone Prompt Guide URL: https://geratools.com/tts-emotion-guide Guide and generator for eliciting emotional delivery from AI text-to-speech. Pick an emotion and platform to get ready-to-use direction techniques — parenthetical cues like (laughing), interjections, and pacing markup — formatted for your TTS engine. How to use: 1. Pick the emotion: Choose the emotional delivery you want, from cheerful to somber. The guide shows the cues that reliably trigger that tone. 2. Choose your TTS platform: Select ElevenLabs, OpenAI TTS, or generic SSML. The markup differs — parenthetical cues for some, SSML tags for others. 3. Apply the formatted example: Copy the example line wrapping your text in the right cues and pacing, then paste it into your TTS tool. FAQ: Q: Why do parenthetical cues like (laughing) work? A: Modern expressive TTS models are trained on audio that includes non-speech sounds and stage directions. Including a bracketed cue nudges the model toward that delivery, though support varies by engine. Q: Does every platform support the same cues? A: No. ElevenLabs responds well to inline parenthetical and punctuation cues, OpenAI TTS takes a tone instruction in the request, and SSML engines need explicit tags like prosody and emphasis. The guide formats for the one you pick. Q: How does punctuation change delivery? A: Ellipses add hesitation, em dashes create abrupt breaks, exclamation marks raise energy, and ALL CAPS can increase emphasis. Combined with emotion cues they shape pacing without any special markup. Q: Will cues always be read aloud? A: Sometimes a model speaks the cue text instead of acting on it. Test short clips first, and if a cue is read literally, switch to punctuation and pacing techniques instead. #### Video Generation Negative Prompt Guide URL: https://geratools.com/video-prompt-negative-guide Build curated negative prompts for video AI tools to avoid common artifacts — temporal flicker, morphing faces, text artifacts, watermarks, and jitter. Platform-specific presets, copy-ready, in your browser. How to use: 1. Pick your platform: Choose the video tool you use. Some, like Runway and Kling, accept a dedicated negative prompt field; others only respond to phrasing in the main prompt. 2. Select the issues to fix: Tick the artifacts you keep seeing — flicker, morphing, watermarks, text, jitter, or extra limbs. The guide assembles the matching negative terms. 3. Copy the negative prompt: Copy the assembled list into the negative-prompt field, or fold it into your main prompt as "avoid …" if your tool has no negative field. FAQ: Q: Do all AI video tools support negative prompts? A: No. Runway and Kling expose a negative-prompt field; Sora and some others do not. For those, phrase the same terms as "no watermark, no flicker" inside the main prompt. Q: How do I stop morphing faces in AI video? A: Add negatives like "morphing, distorted face, melting features, inconsistent identity" and reduce commanded motion. Keeping one clear subject and a steady camera helps most. Q: Can negative prompts remove watermarks? A: Negatives like "watermark, text overlay, logo" reduce the chance of the model hallucinating them, but they can't remove a watermark baked into training data on every output — choose a clean model if it persists. Q: Is anything uploaded? A: No. The guide builds a text list in your browser. You copy it and paste it into your video tool; nothing you select is stored or sent. #### Video Storyboard Prompt Sequencer URL: https://geratools.com/video-storyboard-prompt-sequence Multi-panel builder for shot-by-shot AI video generation. Maintains character and environment consistency tokens across panels and exports a clean, numbered prompt sequence. Runs entirely in your browser. How to use: 1. Define your anchors: Enter a fixed character description and environment. These consistency tokens are prepended to every shot so the model holds identity across clips. 2. Write each shot: Add a line for each shot describing the action and camera. The sequencer numbers them and shares the anchors automatically. 3. Export the sequence: Copy the full numbered prompt list and generate each shot in turn, keeping the anchor tokens identical for continuity. FAQ: Q: How do I keep a character consistent across AI video shots? A: Repeat an identical, detailed character description in every prompt — same name, clothing, age, and distinguishing features. This tool prepends those tokens to each shot so they never drift. Q: Why generate shot by shot instead of one long clip? A: AI video holds motion and identity far better in short clips. Generating each shot separately, then editing them together, gives cleaner results than one long, motion-heavy generation. Q: Can I reorder or add shots? A: Yes — add as many shots as your sequence needs and edit each line. The numbering and shared anchors update automatically when you copy the output. Q: Is my storyboard stored anywhere? A: No. Everything is assembled in your browser and exists only in the page. You copy the result yourself; nothing is uploaded or saved. #### Video-to-Prompt Reverse Engineering Guide URL: https://geratools.com/video-to-prompt-reverse-engineer A framework for reverse-engineering AI video prompts from reference clips. Walks you through identifying camera movement, lighting, subject description, motion type, and style, then assembles a recreatable prompt for Runway, Kling, Sora, or Luma. How to use: 1. Watch and break down the clip: Describe the reference clip's subject, then work through camera movement, lighting, and motion using the structured fields. 2. Note the platform: Pick the platform the video was likely made with so the assembled prompt uses syntax that travels well to that tool. 3. Copy the recreatable prompt: The tool combines your observations into an ordered prompt you can paste and iterate on to approach the reference look. FAQ: Q: Can I exactly recreate an AI video from a prompt? A: Rarely exactly — seeds, model versions, and randomness all vary. But a well-structured prompt that captures subject, camera, lighting, motion, and style gets you very close, and iterating from there closes the gap. Q: What should I look at first in a reference clip? A: Start with camera movement, because it shapes everything else. Identify whether the camera pushes in, orbits, pans, or stays static, then layer in subject, lighting, and the type of motion in the scene. Q: How do I describe lighting from a video? A: Name the quality and direction — soft window light, hard noon sun, neon rim light, golden hour. Add color temperature (warm or cool) and contrast. These cues drive how the model renders mood and depth. Q: Does this send the video anywhere? A: No. You describe what you observe and the tool assembles text in your browser. No video is uploaded; nothing is stored. #### Writing Improvement Prompt Builder URL: https://geratools.com/writing-improvement-prompt Select concrete improvement goals — clarity, concision, passive voice, jargon reduction, flow — and the tool generates a targeted revision prompt that addresses each issue explicitly while preserving what you ask it to keep. How to use: 1. Choose improvement goals: Tick the specific weaknesses you want fixed — vague clarity asks produce vague edits, so be concrete. 2. Set what to preserve: List anything the edit must not change, such as quotes, technical terms, or the author's voice, so the model edits surgically. 3. Copy the revision prompt: Paste the generated prompt above your text. It instructs the model to address each selected issue and to explain its changes if you asked. FAQ: Q: Why pick specific goals instead of asking to 'improve' my writing? A: 'Improve this' is interpreted differently every run and often rewrites your voice away. Naming concrete targets — cut passive voice, reduce jargon, tighten by 20% — produces consistent, reviewable edits that change only what you intended. Q: What does the preserve list do? A: It tells the model which elements are off-limits — direct quotes, defined terms, names, or a distinctive voice. This keeps the edit surgical and prevents the model from flattening intentional style choices. Q: Should I ask the model to show its changes? A: Yes, when you are reviewing rather than batch-processing. A change log or tracked edits lets you accept or reject each revision instead of trusting a wholesale rewrite. Q: Is my text uploaded anywhere? A: No. The builder only assembles a prompt from your selections. Nothing you type is sent to a server. ### Image, Video & Audio Generation #### AI Voice Provider Comparison Table URL: https://geratools.com/ai-voice-comparison-table Feature matrix comparing top AI text-to-speech providers — voices available, voice cloning, SSML support, latency, pricing model, and API quality. Filter by use case to find the right TTS for your project. How to use: 1. Pick your use case: Filter the table by what you're building — audiobooks, real-time agents, dubbing, or simple narration. The columns that matter most for that use case are highlighted. 2. Toggle feature requirements: Switch on filters like voice cloning or SSML support to hide providers that don't meet your hard requirements. 3. Compare the shortlist: Read the matched rows side by side for latency, pricing model, and API quality, then click through to the provider you choose. FAQ: Q: Which AI voice provider is best for real-time agents? A: For conversational agents you want the lowest latency. OpenAI TTS and ElevenLabs Flash/Turbo models stream in well under a second, which matters far more than maximum fidelity for live calls. Q: Which TTS supports voice cloning? A: ElevenLabs and PlayHT offer instant and professional voice cloning. OpenAI's standard TTS does not let you clone an arbitrary voice — it ships a fixed set of voices. Q: Do all providers support SSML? A: No. Murf and PlayHT support rich SSML for pauses, emphasis, and pronunciation. ElevenLabs uses its own control tokens and limited SSML, while OpenAI TTS exposes almost no markup control. Q: Is the comparison data live? A: No. The matrix reflects publicly documented features at the listed update date and is refreshed periodically. Always confirm current pricing and limits on each provider's own site before committing. #### AI Voice & TTS Model Comparison URL: https://geratools.com/ai-voice-model-comparison Side-by-side reference for text-to-speech and AI voice models covering naturalness, language coverage, voice cloning support, latency, and price per million characters — ElevenLabs, OpenAI TTS, Google, AWS Polly, Azure, and more. How to use: 1. Set your needs: Pick whether you need voice cloning, then filter by provider or budget to narrow the table to the TTS models that match your project. 2. Compare the columns: Read across naturalness, languages, cloning support, latency, and price per million characters to see which voice model fits your use case. 3. Sort to rank: Click any column header to sort ascending or descending so you can rank models by price, naturalness, or latency. FAQ: Q: Which TTS API sounds the most natural? A: ElevenLabs is widely considered the most natural for English and offers expressive emotion control, with OpenAI TTS close behind. Google and Azure Neural voices are strong and far cheaper at high volume, while AWS Polly Neural is reliable but slightly less expressive. Q: Which voice APIs support voice cloning? A: ElevenLabs offers instant and professional voice cloning, and Microsoft Azure offers Custom Neural Voice (gated for ethics review). OpenAI TTS, Google Cloud TTS, and AWS Polly Neural do not offer general-purpose cloning as of mid-2026. Q: How is price per character calculated? A: TTS is billed per character of input text, usually quoted per 1 million characters. Prices are list-price estimates and clearly labelled; tiers, free quotas, and per-voice surcharges vary, so confirm in each provider's pricing page. Q: What latency should I expect for real-time voice? A: For conversational agents you want sub-300ms first-byte latency. ElevenLabs Flash and OpenAI's streaming TTS hit low latency; standard high-quality voices are higher latency and better suited to pre-rendered audio. Q: How many characters is an hour of speech? A: English narration runs about 150–165 words per minute and prose averages roughly 6 characters per word including spaces, so one hour of continuous audio corresponds to roughly 54,000–60,000 input characters. An 80,000-word audiobook is about 480,000 characters. Q: Do SSML tags count toward TTS billing? A: It varies by provider. Some bill every input character including SSML markup; others bill only the synthesized text. If your pipeline adds heavy prosody or say-as tags, confirm the billing treatment on the provider's pricing page before estimating costs from raw text length. #### Automatic1111 WebUI Settings Guide URL: https://geratools.com/automatic1111-settings-guide Guide to Automatic1111 WebUI settings — Stable Diffusion options, VAE, optimization, face restoration, upscaling, and sampling defaults. Filter by category and use case to see what each setting does and a recommended starting value. How to use: 1. Pick a settings category: Choose a tab area — generation, VAE/CLIP, optimization, face restoration, or upscaling — to see the settings grouped the way the WebUI presents them. 2. Set your use case: Select a use case (photoreal, anime, speed) to get a recommended value tuned for that workflow rather than a generic default. 3. Apply and restart where needed: Some settings (xformers, model VAE) take effect on restart. The guide flags which ones require relaunching the WebUI. FAQ: Q: What does Clip Skip do and what should I set it to? A: Clip Skip controls how many of the final CLIP text-encoder layers are skipped when encoding your prompt. Photoreal SD 1.5 and SDXL models generally want Clip Skip 1. Many anime and NovelAI-derived models are trained expecting Clip Skip 2, which gives cleaner results on those checkpoints. Match it to the model's documentation. Q: Do I need a separate VAE? A: Some checkpoints ship with a baked-in VAE and some do not. If your outputs look washed out, overly gray, or have purple artifacts, loading a dedicated VAE (like the SDXL VAE or vae-ft-mse for SD 1.5) usually fixes it. Set it in Settings under the VAE section so it applies globally. Q: What is xformers and should I enable it? A: xformers is a memory-efficient attention implementation that speeds up generation and lowers VRAM use on NVIDIA cards. Enable it with the --xformers launch flag if your card supports it. On newer PyTorch builds, the built-in SDP attention is an alternative that needs no extra install. Q: Are these the only settings? A: No. Automatic1111 exposes hundreds of options across many tabs, plus extension settings. This guide covers the high-impact settings most people need to get good output, organized by area, rather than documenting every checkbox. #### ComfyUI Node Reference Card URL: https://geratools.com/comfyui-node-reference Interactive reference card for core ComfyUI nodes — KSampler, VAE Encode/Decode, CLIP Text Encode, LoRA Loader, ControlNet Apply, Upscale, and more. Filter by category or search by name to see each node's inputs, outputs, and data types. How to use: 1. Filter by category: Use the category dropdown to narrow to loaders, sampling, conditioning, latent, or image nodes. Each category groups nodes that connect naturally in a graph. 2. Search by node name: Type a node name or keyword to jump straight to it. Matches the node title and its inputs and outputs. 3. Read the wiring: Each card lists inputs, outputs, and their data types (MODEL, LATENT, CONDITIONING, IMAGE, VAE) so you know which sockets connect to which. FAQ: Q: What are the core data types in ComfyUI? A: The main types you wire between nodes are MODEL (the diffusion UNet), CLIP (the text encoder), VAE (the latent encoder/decoder), CONDITIONING (encoded prompts), LATENT (the working image in latent space), and IMAGE (pixel-space output). A socket only connects to a matching type, which is why the reference lists types explicitly. Q: Why does KSampler take a LATENT instead of an image? A: Stable Diffusion denoises in a compressed latent space, not pixel space. KSampler operates on a LATENT, and you only convert back to a viewable IMAGE at the end with a VAE Decode. Empty Latent Image creates a blank canvas of the right size to start a text-to-image run. Q: Is this every ComfyUI node? A: No. ComfyUI has hundreds of nodes plus thousands from custom node packs. This card covers the core built-in nodes that appear in almost every workflow, which is what most people need when learning or debugging a graph. Q: Does this run a workflow or just describe nodes? A: It is a reference card only — it describes each node's inputs, outputs, and purpose. Build and run actual graphs inside ComfyUI; use this to remember what connects to what. #### ComfyUI Workflow Planner URL: https://geratools.com/comfyui-workflow-planner Plan ComfyUI pipelines before you build them. Select a base model and the nodes you intend to use — KSampler, VAE, LoRA, ControlNet, upscaler, IPAdapter — and get peak VRAM estimates, a fit check against your GPU, and batch-size recommendations. How to use: 1. Pick your base model: Choose the checkpoint your workflow loads — SD 1.5, SDXL, Flux, or SD3. This sets the largest single VRAM cost. 2. Select your nodes: Tick the nodes you plan to chain. ControlNet, IPAdapter, and upscalers each add their own VRAM on top of the checkpoint. 3. Enter GPU VRAM and batch: Type your card's VRAM and intended batch size. The planner estimates peak usage, checks whether it fits, and suggests a safe maximum batch. FAQ: Q: How accurate are the VRAM estimates? A: They are rough planning figures at fp16 and 1024px, meant to tell you whether a workflow is comfortable, tight, or impossible on your card. Real usage shifts with resolution, sampler, and attention optimizations, so treat the number as a guide rather than a guarantee. Q: Which node uses the most VRAM? A: After the checkpoint itself, ControlNet is usually the largest single addition because it loads a second model. IPAdapter and upscalers are next. KSampler is already accounted for in the base model, so it adds nothing extra. Q: How does batch size affect memory? A: Model weights load once regardless of batch, but the latent activations scale with each additional image. The planner adds roughly a quarter of the base model's footprint per extra image in the batch and suggests the largest batch that still fits. Q: What if my workflow does not fit? A: Switch to fp8 or quantized weights, enable tiled VAE and tiled upscaling, run ComfyUI with --lowvram or --medvram to offload to system RAM, or reduce batch size and resolution. The planner flags the shortfall so you know how much to cut. #### DALL·E API Playground URL: https://geratools.com/dalle-api-playground Browser-based interface for calling the OpenAI Images API with your own key. Supports the DALL·E 3 parameters — size, quality, and style — with a live cost preview before generation. Your key stays in the browser and is never stored on a server. How to use: 1. Paste your OpenAI key: Enter your own OpenAI API key. It is held only in your browser's memory for the request and is never stored or sent anywhere except OpenAI. 2. Set the prompt and options: Write a prompt and choose size, quality, and style. The estimated cost updates live so you know the charge before you commit. 3. Generate and review: Click generate to call the OpenAI Images API directly from your browser. The returned image appears inline with the revised prompt OpenAI used. FAQ: Q: Is my API key safe? A: The key never leaves your browser except in the direct HTTPS request to OpenAI's own API. This tool has no backend, stores nothing, and does not transmit your key to Gera or any third party. Q: How much does a DALL·E 3 image cost? A: Pricing depends on size and quality. Standard 1024×1024 is the cheapest tier; HD quality and the larger 1792-pixel sizes cost more. The tool shows the current estimate for your selected options before you generate. Q: Why did my request fail with a 401? A: A 401 means the API key is missing, invalid, or lacks access to the Images API. Confirm you pasted a valid key with image-generation permissions and an active billing setup on your OpenAI account. Q: What is the revised prompt? A: DALL·E 3 automatically rewrites your prompt for safety and detail before generating. The API returns this revised prompt, which the playground displays so you can see exactly what was rendered. #### ElevenLabs Voice Settings Advisor URL: https://geratools.com/elevenlabs-voice-settings-guide Interactive advisor for ElevenLabs voice settings — stability, similarity boost, and style exaggeration. Pick a use case and tone to get recommended slider values for narration, character, ads, and audiobooks, all in your browser. How to use: 1. Pick your use case: Choose what you are generating — narration, character voice, advertisement, audiobook, or conversational. 2. Set your priority: Tell the advisor whether you want maximum consistency or more expressive variation, and how strongly to match the source voice. 3. Apply the recommended sliders: Copy the suggested stability, similarity boost, and style values into the ElevenLabs voice settings panel and fine-tune from there. FAQ: Q: What does stability control in ElevenLabs? A: Stability governs how consistent the voice sounds across a generation. Lower values make the delivery more varied and emotional but can wander or glitch. Higher values are steadier and more monotone. Most narration sits around 0.4 to 0.6. Q: What is similarity boost? A: Similarity boost controls how closely the output matches the original voice sample. Higher values cling tightly to the source timbre, which helps cloned voices but can amplify any background noise present in the training audio. Q: What does style exaggeration do? A: Style amplifies the speaking style and emotion of the original voice. It can add life to flat readings but raising it increases generation time and instability, so keep it low unless you specifically want a dramatic delivery. Q: What settings are best for audiobooks? A: Audiobooks favor consistency over drama — try stability around 0.5 to 0.65, similarity boost around 0.75, and style near 0. This keeps a long read steady so the listener does not get jarred by sudden tonal shifts. Q: Should I enable speaker boost? A: Speaker boost increases fidelity to the original speaker at a small latency cost. It is usually worth enabling for cloned voices and narration, and optional for high-throughput conversational use where latency matters. #### Midjourney Aspect Ratio Calculator URL: https://geratools.com/midjourney-ar-calculator Free Midjourney aspect ratio calculator. Enter width and height in pixels and get the simplified --ar flag, plus the nearest supported MJ v5/v6 ratio and a visual preview of the frame shape. Runs entirely in your browser. How to use: 1. Enter width and height: Type the target image width and height in pixels — for example 1920 by 1080. 2. Read the simplified ratio: The tool divides both numbers by their greatest common divisor to give the lowest-terms aspect ratio, then formats it as Midjourney expects. 3. Copy the --ar flag: Copy the resulting --ar W:H flag and append it to your /imagine prompt. FAQ: Q: What aspect ratios does Midjourney support? A: Since v5 Midjourney accepts almost any aspect ratio you pass to --ar, from extreme panoramas to tall portraits. Earlier versions were limited to a handful of presets. Very extreme ratios (beyond roughly 7:1) can still produce repetition or stitching artifacts, so the tool flags when a ratio is unusually wide or tall. Q: How do I turn pixel dimensions into an --ar flag? A: Divide both the width and the height by their greatest common divisor. For example 1920x1080 has a GCD of 120, giving 16:9. Midjourney does not render at your exact pixel count — --ar only sets the shape of the frame, and the model picks a resolution that fits that shape. Q: Does --ar control the output resolution? A: No. --ar only sets the proportions of the image. Midjourney chooses the actual pixel resolution based on the version and quality setting. To get a larger file you upscale the result rather than passing a bigger pixel size. Q: What is the default Midjourney aspect ratio? A: The default is 1:1 (square). If you do not include an --ar flag, Midjourney generates a square image. Pass --ar 16:9 for widescreen, --ar 9:16 for vertical/mobile, or any other ratio you need. Q: Why does my ratio look different from what I typed? A: The calculator reduces your dimensions to lowest terms, so 1280x720 and 1920x1080 both display as 16:9 — they are the same shape. The decimal ratio shown beside it (1.778) confirms the exact proportion before rounding. #### Midjourney /blend Mode Guide URL: https://geratools.com/midjourney-blend-guide Guide to Midjourney's /blend command — recommended image count, dimension and aspect-ratio matching advice, expected output behavior, and how blending differs from image prompting. Pick your inputs to get tailored guidance. How to use: 1. Choose how many images to blend: Select between 2 and 5 source images. The guide explains how the count affects how evenly traits mix and warns where results get muddy. 2. Pick a desired blend style: Tell the tool whether you want an even 50/50 merge, a dominant base with accents, or a style transfer. It maps that to dimension and ordering advice. 3. Apply the guidance: Read the recommended aspect-ratio option, ordering tips, and a note on when to use /blend versus an image prompt instead. FAQ: Q: How many images can /blend take? A: Midjourney's /blend command accepts between 2 and 5 images. Two images give the cleanest, most predictable merge; four or five images tend to average out into a softer, less defined result. Q: Does image order matter in /blend? A: Order has only a mild effect — /blend treats inputs fairly evenly rather than as a base-plus-overlay. If you need one image to dominate, use it as an image prompt with a text prompt instead, where you can weight it. Q: What aspect ratio does /blend output? A: /blend offers a dimensions option — portrait, square or landscape. It does not infer the ratio from your inputs, so set it explicitly. Square is the safest default when your sources have mixed shapes. Q: How is /blend different from an image prompt? A: /blend merges several images with no text prompt, ideal for fusing aesthetics. An image prompt combines one or more reference images with a text prompt and lets you control influence via image weight (--iw). Use image prompts when you need text guidance or weighting. Q: Why is my blend muddy? A: Blending too many images, or images with very different subjects and palettes, averages detail away. Stick to 2–3 visually compatible images and matching orientation for crisp results. #### Midjourney Character Reference (--cref) Guide URL: https://geratools.com/midjourney-character-reference-guide Guide to Midjourney's --cref character reference and --sref style reference parameters. Covers weight settings (--cw, --sw), image URL requirements and multi-reference combination strategies for consistent characters. How to use: 1. Choose reference type: Pick character reference (--cref) to keep a person consistent, or style reference (--sref) to keep an art style consistent across images. 2. Set the weight: For --cref, the character weight --cw runs 0-100, where 100 copies face, hair and clothes and lower values copy face only. For --sref, the style weight --sw runs 0-1000. 3. Copy the parameter string: Paste your image URL and the generated parameters onto the end of your Midjourney prompt and run it. FAQ: Q: What is the difference between --cref and --sref? A: --cref (character reference) tells Midjourney to keep a character's appearance consistent across generations, while --sref (style reference) tells it to match an art style, palette and rendering rather than a specific person. Q: What does --cw control? A: --cw is the character weight from 0 to 100. At 100 Midjourney tries to match the face, hair and clothing of the reference. Lowering it toward 0 keeps only the face, letting you restyle outfit and setting freely. The default is 100. Q: Can I use a local image as a reference? A: No. --cref and --sref require a publicly reachable image URL. Upload your image to Discord or another host first, then paste its direct URL. You can list several URLs after one --cref or --sref to blend references. Q: Which Midjourney versions support these parameters? A: --cref and --sref were introduced for Midjourney v6 and are supported in v6 and later (including niji 6). They are ignored on older model versions, so set --v 6 or higher. #### Midjourney --style raw Guide URL: https://geratools.com/midjourney-raw-mode-guide A practical guide to Midjourney's --style raw parameter — when to use it, how it strips the default house look, how it combines with --stylize, and what prompt structures work best for maximum adherence. How to use: 1. Pick your control level: Decide whether you want Midjourney's opinionated default look or tight literal adherence to your prompt, then toggle raw accordingly. 2. Set a stylize value: Choose a --stylize value to control how much artistic flourish Midjourney adds even in raw mode. 3. Copy the suffix: Append the generated parameter string to the end of any prompt. FAQ: Q: What does --style raw actually do? A: It tells Midjourney to apply much less of its trained "house aesthetic" — the automatic color grading, lighting, and compositional polish it adds by default. The result follows your wording more literally, which is ideal for technical, design, or reference work. Q: When should I use the default style instead of raw? A: Use the default when you want beautiful, gallery-ready output and don't mind Midjourney making artistic decisions for you. Default mode is better for moody concept art and atmospheric scenes; raw is better for precise, literal results. Q: Can I use --style raw with --stylize together? A: Yes. Raw reduces the baseline house look, and --stylize then controls how much flourish is layered back on. Pairing raw with a low stylize value (around 0–100) gives the most literal, controllable output. Q: Does --style raw work on all model versions? A: Raw is supported on recent Midjourney models (v5.1 and later, including v6 and niji). On older versions the parameter is ignored. Always confirm against your current model in Discord or the web app. #### Midjourney Stylize Explorer URL: https://geratools.com/midjourney-stylize-explorer Interactive reference for Midjourney's --stylize parameter. Move the slider from 0 to 1000 to see what each level does to literalness versus artistic interpretation, with annotations and copy-ready flag snippets for every step. How to use: 1. Move the stylize slider: Drag the slider from 0 to 1000 to land on a stylize value. The tool snaps to the documented checkpoints and explains what each one does. 2. Pick your prompt type: Choose whether your prompt is literal (logos, diagrams, product shots) or artistic (illustration, concept art) to get a tailored recommendation. 3. Copy the flag: Copy the generated --stylize flag and append it to your /imagine prompt. FAQ: Q: What does --stylize do in Midjourney? A: The --stylize parameter (range 0 to 1000, default 100) controls how strongly Midjourney applies its own trained aesthetic on top of your prompt. Low values stay close to a literal reading of your words; high values let the model add colour, composition, and artistic flourishes you did not explicitly ask for. Q: What is the default stylize value? A: The default is 100. The shorthand presets in Discord map to numbers — --s 50 is low, the default is 100, --s 250 is medium, --s 750 is high, and --s 1000 is the maximum. You can also pass any integer in between. Q: When should I use a low stylize value? A: Use low stylize (0 to 100) when accuracy matters more than beauty — logos, UI mockups, diagrams, product photography, or anything where the model adding its own flourishes would hurt. Low values keep Midjourney honest to your exact wording. Q: When should I use a high stylize value? A: Use high stylize (500 to 1000) for illustration, concept art, posters, and mood pieces where you want the model to make confident artistic choices. High values produce richer colour and composition but can drift away from literal prompt details. Q: Does stylize affect render time or cost? A: No. Unlike --quality, the --stylize value does not change how long an image takes to render or how many GPU minutes it consumes. It only changes the look. You can experiment freely with stylize without affecting your subscription usage. #### Midjourney Version Comparator URL: https://geratools.com/midjourney-version-comparator Compare Midjourney versions v4, v5, v5.2, v6, and v7 side by side. See differences in photorealism, aspect ratio support, niji mode, inpainting, default stylize, and which --version flag to use, with copy-ready flags. How to use: 1. Select versions to compare: Tick the Midjourney versions you want to see side by side — pick two or more to highlight the differences. 2. Read the capability matrix: Each row is a capability — photorealism, aspect ratio, niji mode, inpainting, and more — so you can see at a glance which version fits your project. 3. Copy the version flag: Copy the --version (or --niji) flag for your chosen version and append it to your /imagine prompt. FAQ: Q: Which Midjourney version should I use? A: For most work in 2026, v6 or v7 give the best photorealism, prompt understanding, and text rendering. Use niji mode for anime and illustration. Older versions (v4, v5) are mainly useful for reproducing a specific older aesthetic or matching an existing project's look. Q: How do I set the Midjourney version? A: Append --version (or --v) followed by the number, for example --v 6. You can also set a default version with the /settings command in Discord so you do not have to type the flag each time. For niji, use --niji 6 instead. Q: What is niji mode in Midjourney? A: Niji is a specialised model tuned for anime and illustration styles, developed with Spellbrush. It excels at clean line art, expressive characters, and dynamic poses. Invoke it with --niji 5 or --niji 6 rather than the standard --v flag. Q: Does Midjourney v6 support inpainting? A: Yes. From v6 onward Midjourney supports region editing (often called Vary Region or inpainting), letting you select part of an image and regenerate just that area with a new prompt. Earlier versions did not have this feature. Q: What changed in Midjourney v6 versus v5? A: v6 brought much stronger prompt comprehension, far better in-image text rendering, more coherent details, and support for region editing. It also reads longer, more natural-language prompts well, whereas v5 responded better to comma-separated keyword lists. #### OpenAI TTS Voice Picker URL: https://geratools.com/openai-tts-voice-picker Reference and matcher for all six OpenAI TTS voices — alloy, echo, fable, nova, onyx, shimmer. Pick a use case and tone to get the best-fit voice, with descriptions, sample phrases, speed, and audio-format guidance. Runs in your browser. How to use: 1. Choose your use case: Select what you are building — narration, assistant, audiobook, ad, or character. 2. Set a tone preference: Indicate whether you want a warm, neutral, or authoritative feel and the picker shortlists matching voices. 3. Use the recommended voice: Pass the suggested voice name to the OpenAI speech endpoint and adjust speed and format from the notes. FAQ: Q: How many voices does OpenAI TTS offer? A: The core OpenAI speech models ship six built-in voices — alloy, echo, fable, nova, onyx, and shimmer. They each have a distinct tone, and the same voice name works across the tts-1 and tts-1-hd models. Q: Which OpenAI voice is best for narration? A: Onyx and alloy tend to work well for narration thanks to a steady, grounded tone, while nova is a good warmer alternative. The right pick depends on your audience and brand, so audition a couple with the same script. Q: Can I change the speaking speed? A: Yes. The speech API accepts a speed parameter, typically from 0.25 up to 4.0, with 1.0 as normal. Slowing slightly improves clarity for instructional content, while speeding up suits skimmable summaries. Q: What audio formats can OpenAI TTS return? A: You can request mp3, opus, aac, flac, wav, and pcm. Use mp3 or aac for general distribution, opus for low-latency streaming, and wav or flac when you need lossless audio for editing. Q: Is the voice the same across tts-1 and tts-1-hd? A: The voice identity is the same, but tts-1-hd renders at higher audio quality with a bit more latency and cost. Use tts-1 for real-time or high-volume use and tts-1-hd for polished published audio. #### SDXL Extension & Fine-tune Model Guide URL: https://geratools.com/sdxl-extension-model-guide Interactive reference to the SDXL model ecosystem — base vs refiner roles, popular fine-tunes like RealVisXL, DreamShaper XL, and Juggernaut XL, compatible adapters such as ControlNet and IP-Adapter, and model picks by output style and use case. How to use: 1. Pick your output style: Choose the look you want — photoreal, illustration, stylized, or general. The guide filters fine-tunes that suit it. 2. Pick your use case: Select what you are building, such as product shots, portraits, or concept art. Recommendations adjust to match. 3. Read the recommended stack: The guide returns a base or fine-tune checkpoint, whether to use the refiner, and the adapters worth adding for your workflow. FAQ: Q: What is the difference between SDXL base and refiner? A: The base model does the bulk of the generation; the refiner is a second smaller model that polishes the final denoising steps for sharper detail. Most modern fine-tunes are trained to produce finished results in one pass, so the separate refiner is increasingly optional. Q: Do I still need the refiner with a fine-tune like Juggernaut XL? A: Usually no. Community fine-tunes such as Juggernaut XL, RealVisXL, and DreamShaper XL already bake in the polish the refiner adds, so running them base-only is faster and often cleaner. Add the refiner only if fine edges or skin texture look soft. Q: Are SDXL 1.0 adapters compatible with these fine-tunes? A: Yes. ControlNet, IP-Adapter, and LoRAs trained for SDXL 1.0 work across SDXL fine-tunes because they share the same architecture and latent space. Always match the adapter's SDXL version, not the specific checkpoint. Q: Does this tool generate images? A: No. It is a static recommendation guide that runs in your browser. It points you to the right checkpoints and adapters to download or load in your own SDXL setup. #### SDXL Native Resolution Picker URL: https://geratools.com/sdxl-resolution-picker Free SDXL resolution picker. Filter the official SDXL training resolutions by aspect ratio, see width, height and megapixels for each, and copy exact width/height values — all in your browser. How to use: 1. Pick an aspect ratio: Filter the list to square, portrait or landscape, or browse all official SDXL training resolutions at once. 2. Read the details: Each resolution shows its exact width and height, simplified aspect ratio and total megapixels, all close to SDXL's native one-megapixel target. 3. Copy the dimensions: Click any resolution to copy its width and height, then paste them into AUTOMATIC1111, ComfyUI, Forge or your SD UI's width and height fields. FAQ: Q: Why does SDXL need specific resolutions? A: SDXL was trained on a fixed set of aspect-ratio buckets centred on about 1024×1024 (one megapixel). Generating at a trained resolution avoids the duplicated heads, stretched bodies and bad framing that appear at off-target sizes. Q: Can I generate larger than 1024 with SDXL? A: You can, but going much above one megapixel in a single pass often produces repeated subjects. The reliable approach is to generate at a native resolution and then upscale, for example with an SD upscaler or hires fix. Q: Do these resolutions work for SD 1.5? A: No. SD 1.5 was trained around 512×512, so these one-megapixel resolutions are too large for it. Use roughly half these dimensions for SD 1.5. Q: Is anything sent to a server? A: No. The picker is a static reference that runs entirely in your browser. Nothing is uploaded, generated or logged. #### SDXL Turbo & Lightning Guide URL: https://geratools.com/sdxl-turbo-guide A practical guide to the distilled SDXL Turbo and Lightning models — the optimal step counts (1, 2, 4, 8), the low CFG scale they require (1.0–2.5), compatible schedulers, and the prompt style that suits near-instant generation. How to use: 1. Pick the distilled model: Choose SDXL Turbo or one of the Lightning checkpoints; each is tuned for a specific step count. 2. Read the recommended steps and CFG: The guide gives the step count and the low CFG value these distilled models require. 3. Apply the scheduler: Use the recommended scheduler and copy the settings into your WebUI or pipeline. FAQ: Q: Why do Turbo and Lightning need so few steps? A: They are distilled models — trained to reproduce in 1 to 8 steps what the base SDXL takes 25 or more steps to do. The denoising trajectory is compressed, so running extra steps wastes time and can even degrade the image. Q: Why must CFG scale be so low for these models? A: Distillation bakes in much of the prompt guidance, so the usual high CFG (7–12) over-saturates and distorts the output. Turbo works best near CFG 1.0, and Lightning typically wants 1.0–2.5. High CFG is the most common mistake with these models. Q: Which scheduler should I use? A: Turbo is designed around the Euler Ancestral sampler with its own scheduler. Lightning works well with Euler or DPM++ SDE using the sgm_uniform or simple scheduler. Mismatched schedulers are a frequent cause of blurry distilled-model output. Q: Are Turbo and Lightning lower quality than base SDXL? A: At their target step counts they are very close to base quality for most subjects, in a fraction of the time. Base SDXL still has an edge on fine detail and complex scenes, which is why many pipelines draft with Lightning and finalize with the full model. #### SDXL Base + Refiner Workflow Guide URL: https://geratools.com/stable-diffusion-xl-base-refiner-guide A guide to the SDXL two-stage pipeline — the base model handles composition up to a switch step, the refiner polishes from that step onward. Covers recommended split ratios, denoising values, and the quality versus speed trade-offs. How to use: 1. Set total steps: Choose the total sampling steps for the full generation (commonly 30–40). 2. Choose the switch point: Pick the fraction of steps where the base hands off to the refiner — typically around 80%. 3. Read the per-model step counts: The tool splits your total into base steps and refiner steps and shows the recommended denoise. FAQ: Q: What is the SDXL refiner for? A: The refiner is a second specialized model trained on the low-noise end of the diffusion process. The base builds the overall composition; the refiner takes over near the end to add fine detail, sharper textures, and cleaner edges. It is most noticeable on faces, hair, and intricate surfaces. Q: What split between base and refiner works best? A: A common starting point is the base handling about 80% of the steps and the refiner the final 20%, often written as a refiner switch around 0.8. So at 40 total steps the base runs ~32 and the refiner ~8. Pushing the refiner share too high can wash out detail. Q: Do I have to use the refiner? A: No. Many fine-tuned SDXL checkpoints and community merges produce excellent results from the base alone and the refiner adds little. The refiner is most valuable on the original Stability base models; test both for your checkpoint. Q: What denoise should the refiner use? A: In the ensemble-of-experts setup the refiner continues the same latent, so its effective denoise is just the remaining noise fraction (around 0.2 if it starts at 80%). If you run the refiner as a separate img2img pass instead, a denoise of about 0.2–0.3 is a good range. #### TTS SSML Markup Builder URL: https://geratools.com/tts-ssml-builder Visual SSML editor for adding speech markup — pauses, emphasis, rate, pitch, and volume — to your text. Outputs valid, copy-ready SSML for AWS Polly, Google Cloud TTS, and Azure Speech, all in your browser. How to use: 1. Paste your text: Drop in the sentence or paragraph you want spoken, then wrap it with the controls. 2. Apply markup: Set a global rate, pitch, and volume, then insert break and emphasis tags where you want pauses or stressed words. 3. Copy the SSML: Copy the generated SSML and paste it into your AWS Polly, Google TTS, or Azure Speech request as the input text. FAQ: Q: What is SSML? A: Speech Synthesis Markup Language is an XML-based standard that lets you control how a TTS engine speaks text. With it you can insert pauses, emphasize words, change speaking rate, pitch, and volume, and spell out abbreviations. Q: Do AWS Polly, Google, and Azure all support the same SSML? A: They share a common core (speak, break, emphasis, prosody, say-as) but each adds engine-specific tags. This builder outputs the common subset that works across all three. Always check provider docs before using vendor-only tags. Q: How do I add a pause? A: Use a break tag with a time value, like a 500 millisecond or one second pause. SSML accepts time in milliseconds (500ms) or seconds (1s), or strength keywords such as weak, medium, and strong. Q: Why isn't my SSML being read as markup? A: Most engines require you to flag the input as SSML rather than plain text — for Polly set TextType to ssml, for Azure use the SSML request body, for Google set input.ssml. If you pass SSML as plain text the tags are read aloud literally. Q: Can I nest prosody and emphasis tags? A: Yes. You can wrap an emphasized word inside a prosody block to combine stress with a slower rate or higher pitch. Keep nesting shallow and always close tags in the reverse order you opened them. #### SSML Prosody Builder URL: https://geratools.com/voice-ssml-prosody-builder Visual builder for SSML tags. Set pitch (presets or relative semitones), rate (presets or percent), and volume (presets or relative dB) and get valid SSML you can paste into AWS Polly or Azure Speech for fine TTS control. How to use: 1. Enter your text segment: Type the sentence or phrase you want to control. It is XML-escaped automatically so special characters stay valid. 2. Set pitch, rate, and volume: Choose presets like 'high' or 'slow', or switch to relative modes for semitone pitch, percent rate, and dB volume. 3. Copy the SSML: Copy the generated markup and paste it into AWS Polly, Azure Speech, or any SSML-compatible TTS engine. FAQ: Q: What does the prosody tag control? A: The SSML tag controls three aspects of synthesized speech — pitch (how high or low), rate (how fast), and volume (how loud). Wrapping text in a prosody tag with these attributes lets you shape delivery without changing the words. Q: Should I use presets or relative values? A: Presets (x-low to x-high, x-slow to x-fast) are simple and portable. Relative values — semitones for pitch, percent for rate, dB for volume — give finer control and are well supported across AWS Polly and Azure Speech. Use relative values when a preset is too coarse. Q: Is the output compatible with both AWS Polly and Azure? A: Yes. The builder emits standard SSML using widely supported prosody attributes (relative semitone pitch, percent rate, relative dB volume, and named presets), which both AWS Polly and Azure Speech accept. Some engines support extra attributes not generated here. Q: Why is my text being escaped? A: SSML is XML, so characters like &, <, and > must be escaped or they break the markup. The builder escapes your text automatically so the output is always valid XML you can paste directly. ### RAG, Agents & Fine-Tuning #### AI Agent Escalation Policy Generator URL: https://geratools.com/ai-agency-escalation-policy Describe your AI agent's capabilities and decision scope to generate a human escalation policy — defining escalation triggers, response time requirements, override procedures, and audit logging for autonomous AI agent actions. How to use: 1. Describe the agent: Enter the agent's capabilities and the kinds of actions it can take on its own. 2. Set the risk level: Choose how reversible and consequential the agent's actions are, and what it can touch. 3. Generate the policy: The tool assembles escalation triggers, response-time targets, override steps, and logging requirements into a draft policy. FAQ: Q: What is an escalation policy for an AI agent? A: It is a set of rules defining when an autonomous agent must stop and hand control to a human, how fast a human must respond, and how the action is logged. It keeps agents inside safe bounds while letting them act independently most of the time. Q: What triggers an escalation? A: Common triggers include actions above a value or impact threshold, low model confidence, irreversible operations, requests touching sensitive data, repeated failures, and anything outside the agent's defined scope. The generator picks triggers based on your risk level. Q: Why do response-time requirements matter? A: If a human must approve an action, the agent is blocked until they do. Setting a response-time target and a timeout fallback (deny or queue) prevents the agent from either stalling indefinitely or proceeding unreviewed. Q: Is the generated policy production-ready? A: It is a strong first draft covering the structure auditors expect. You should adapt thresholds, owners, and timeouts to your organisation and have it reviewed before adopting it. Q: Is anything uploaded? A: No. The policy is assembled in your browser from your inputs. Nothing is sent to a server. #### AI Agent Design Planner URL: https://geratools.com/ai-agent-design-planner A guided planner for defining your AI agent's goal, memory types, tool access, escalation paths, and evaluation criteria that outputs a structured design-document prompt so you architect the agent before writing a line of code. How to use: 1. Define the goal and tools: State the agent's single primary goal and list the tools or APIs it may call so scope and capability are explicit up front. 2. Choose memory and escalation: Pick the memory model and define when the agent must hand off to a human so autonomy boundaries are clear. 3. Copy the design-doc prompt: Paste the generated prompt into any LLM to produce a complete agent design document you can review with your team before building. FAQ: Q: Why design before coding an agent? A: Agents fail in subtle ways — runaway loops, tool misuse, no escalation path. Designing the goal, memory, tools, guardrails, and evals first surfaces those risks on paper, where they are cheap to fix, instead of in production where they are expensive. Q: What memory types does it cover? A: It distinguishes none (stateless), short-term (within a single task or conversation), and long-term (persisted across sessions, often via a vector store or database). The prompt asks the model to justify the choice and define what is stored and for how long. Q: How does it handle tool access? A: You list each tool the agent may use; the prompt instructs the model to define inputs, outputs, side effects, and a least-privilege boundary for each, plus what happens when a tool call fails. Q: What are escalation paths? A: Conditions under which the agent must stop and hand control to a human — low confidence, irreversible actions, repeated failures, or policy-sensitive decisions. The design doc makes these explicit so the agent is never fully unsupervised on high-stakes actions. Q: Does it cover evaluation? A: Yes. The output design doc includes success criteria, failure modes to test, and the metrics you will track, so you can tell whether the agent actually works before and after launch. #### Embedding Model Comparison Table URL: https://geratools.com/ai-embedding-model-comparison A filterable reference table of popular text embedding models from OpenAI, Cohere, Voyage AI, Jina, and open-source providers, comparing dimensions, max input tokens, price per million tokens, and benchmark scores to pick the right model. How to use: 1. Pick your task type: Choose whether you are doing semantic search, classification, or clustering so the table highlights models suited to that use. 2. Apply cost and latency filters: Filter to budget-friendly or low-dimension models to narrow the list to options that fit your constraints. 3. Compare the shortlist: Read across dimensions, max tokens, price, and benchmark score, then validate the top candidates on your own data. FAQ: Q: What is MTEB and why does it matter? A: MTEB is the Massive Text Embedding Benchmark, a public suite that scores embedding models across retrieval, classification, clustering, and more. A higher average is a useful signal of general quality, but it is not a substitute for testing on your own domain data. Q: Do more dimensions always mean better embeddings? A: No. Higher-dimensional vectors can capture more nuance but cost more to store and search and are slower at scale. Many modern models support dimension reduction (Matryoshka) so you can trade a little quality for much cheaper storage and faster search. Q: How do I read the price column? A: Prices are shown per million input tokens, the standard unit providers bill on. To estimate cost, multiply your total tokens to embed by the price and divide by one million. Open-source models show as self-hosted, where you pay infrastructure rather than per token. Q: Which model is best for retrieval-augmented generation? A: For RAG, prioritize retrieval performance and max input tokens so you can embed larger chunks. A high MTEB retrieval score and strong multilingual support matter most; the table lets you filter to strong general models and compare their context limits. Q: Are these numbers exact and current? A: They are representative figures to guide a shortlist, and providers update models and pricing frequently. Always confirm the latest dimensions, limits, and prices on the provider's own documentation before committing. #### RAG Context Pruner URL: https://geratools.com/context-pruner Score each sentence of your retrieved RAG context by keyword overlap with the query, filter out everything below a threshold you control, and preview the pruned context with the token savings — entirely in your browser. How to use: 1. Enter query and context: Paste the user query and the retrieved context block that you would normally pass to the model. 2. Set a relevance threshold: Choose how strict to be. Each sentence is scored by overlap with the query terms, and sentences below the threshold are dropped. 3. Copy the pruned context: Review the kept sentences and the token savings, then copy the pruned context for your prompt. FAQ: Q: How is relevance scored? A: Each sentence gets a score based on how many distinct query keywords it contains, normalised by the query length. Stop words are ignored so common words do not inflate scores. Q: Will this beat a real reranker? A: No. Lexical overlap is a cheap heuristic and cannot match an embedding cross-encoder for semantic relevance. It is a fast, free first pass that removes obviously off-topic sentences before a smarter step. Q: Why prune context at all? A: Retrieved chunks often carry boilerplate and tangential sentences that waste tokens and dilute the model's attention. Pruning lowers cost and can improve answer quality by raising signal density. Q: Does anything leave my browser? A: No. All scoring and filtering run client-side in JavaScript. Your query and context never leave the page. #### Cosine Similarity Calculator URL: https://geratools.com/cosine-similarity-calculator Paste two vectors as comma-separated floats or JSON arrays and instantly get their cosine similarity, dot product, and L2 norms. Shows the formula and a plain-language interpretation of the result for embeddings work. How to use: 1. Paste vector A: Enter the first embedding as comma-separated numbers or a JSON array of floats. 2. Paste vector B: Enter the second vector of the same length. 3. Read the result: See the cosine similarity along with the dot product and each vector's L2 norm, plus an interpretation. FAQ: Q: What does cosine similarity measure? A: It measures the angle between two vectors, ignoring their magnitude. Values range from -1 (opposite direction) through 0 (orthogonal, unrelated) to 1 (identical direction). For text embeddings it is the standard measure of semantic similarity. Q: Why does it ignore magnitude? A: Many embedding models encode meaning in direction rather than length. Cosine similarity normalises out the magnitude so two vectors pointing the same way score 1 even if one is longer, which is usually what you want for semantic comparison. Q: What if the vectors are different lengths? A: Cosine similarity is only defined for vectors of equal dimension. The tool will tell you if the lengths differ so you can fix the input rather than getting a misleading number. Q: Is my data processed locally? A: Yes. The calculation runs in your browser with no network calls, so embeddings you paste are never uploaded or stored. #### Embedding Model Comparison Table URL: https://geratools.com/embedding-model-comparison Searchable, sortable comparison of major text embedding models — dimensions, max input tokens, cost per 1M tokens, and MTEB benchmark scores for OpenAI, Cohere, Voyage, and open-source options. How to use: 1. Filter the table: Use the provider dropdown and search box to narrow the list to the models you care about — for example only OpenAI models, or models with fewer than 1024 dimensions. 2. Compare the columns: Read across dimensions, max tokens, cost per million tokens, and MTEB score. Higher MTEB is better retrieval quality; lower dimensions mean cheaper storage. 3. Sort to rank: Click any column header to sort ascending or descending so you can rank models by cost, quality, or vector size for your use case. FAQ: Q: What is MTEB? A: MTEB is the Massive Text Embedding Benchmark, a public leaderboard scoring embedding models across dozens of retrieval, clustering, and classification tasks. A higher average MTEB score generally indicates better embedding quality. Q: Do more dimensions always mean better quality? A: No. More dimensions can capture more nuance but cost more to store and search, and some lower-dimension models outperform larger ones on MTEB. Match dimensions to your storage budget and recall needs. Q: Are these prices current? A: Prices are list-price estimates and clearly labelled. Providers change pricing frequently, so confirm the current rate in your provider's dashboard before budgeting. Q: Can I shorten OpenAI embedding dimensions? A: Yes. text-embedding-3 models support Matryoshka dimension truncation, so you can request fewer dimensions (e.g. 256 or 512) to cut storage cost with only a small quality loss. #### Textual Inversion Embedding Guide URL: https://geratools.com/embedding-textual-inversion-guide Guide for using Textual Inversion embeddings in Stable Diffusion prompts. Covers the difference between bare-name and angle-bracket syntax across WebUI and ComfyUI, where to place positive and negative embeddings, and how to adjust their weight. Generates copy-ready prompt snippets. How to use: 1. Enter the embedding name: Type the filename of your embedding without the extension — for example easynegative or my-style. This is the trigger token the model recognises. 2. Choose where it goes: Decide whether it is a positive embedding (a style or subject you want) or a negative one (artifacts you want to avoid) so it lands in the correct prompt box. 3. Copy the generated syntax: The tool outputs the exact token for WebUI and ComfyUI, with an optional weight, ready to paste straight into your prompt. FAQ: Q: What is a Textual Inversion embedding? A: A Textual Inversion embedding is a small file that teaches Stable Diffusion a new concept — a style, character or quality fix — and binds it to a trigger word. Typing that word in your prompt invokes the learned concept without changing the base model. Q: Do I write the embedding name or use angle brackets? A: In Automatic1111/Forge you just type the embedding's filename as a plain word, for example easynegative. In ComfyUI the standard syntax is embedding:name. Either way the name must match the file in your embeddings folder exactly. Q: Where do I put a negative embedding? A: Negative embeddings such as easynegative or badhandv4 go in the negative prompt box. They steer the model away from the artifacts they were trained on, like deformed hands or watermarks. Q: How do I change an embedding's strength? A: Wrap it in weight syntax just like any token — (easynegative:0.8) in WebUI, or use the same parenthesis weighting in ComfyUI. Lower the weight if the embedding is overpowering the rest of the prompt. #### RAG Architecture Planner URL: https://geratools.com/rag-architecture-planner A guided planner that recommends a chunking strategy, embedding model, vector store, and retrieval evaluation approach for your corpus size, document types, latency target, and budget — then summarises the full RAG stack to copy. Runs locally. How to use: 1. Describe your corpus: Enter your document types, corpus size, latency target, and budget posture. 2. Let the planner choose components: The planner recommends a chunking strategy, embedding model, vector store, and retrieval/eval approach matched to your inputs. 3. Copy the stack summary: Copy the assembled RAG architecture summary into your design doc and refine from there. FAQ: Q: What is RAG? A: Retrieval-Augmented Generation injects relevant documents into the model's prompt at query time, so the LLM answers from your private, current knowledge without retraining. It is the standard way to ground an assistant in facts that change or that the model never saw in training. Q: How does corpus size change the recommendation? A: Small corpora can use a lightweight or in-process vector store and simple chunking, while large corpora need a scalable managed vector database, metadata filtering, and often hybrid (keyword + vector) search to keep recall high and latency acceptable. Q: Which embedding model should I pick? A: For most use cases a strong general embedding model (such as a current OpenAI or open-source model) is the right default. Choose larger-dimension models for nuanced semantic recall, smaller/cheaper ones when cost and latency dominate, and a multilingual model if your corpus spans languages. Q: Why does the planner stress evaluation? A: RAG quality lives or dies on retrieval. Without measuring recall and answer faithfulness on a labelled question set, you cannot tell whether a bad answer came from retrieval missing the chunk or the model ignoring it. The planner always recommends a small golden eval set. #### RAG Pipeline Designer URL: https://geratools.com/rag-pipeline-designer Toggle and configure the stages of a RAG pipeline — loader, splitter, embedder, vector store, retriever, reranker, generator — then export a copy-ready Mermaid diagram and Python-style pseudocode for your stack. How to use: 1. Pick your stages: Enable the stages your pipeline needs — every RAG flow has a loader, splitter, embedder, store, retriever, and generator; the reranker and query-rewrite stages are optional boosters. 2. Configure each stage: Set chunk size, top-k, embedding model, and reranker so the generated diagram and pseudocode reflect your real configuration. 3. Export: Copy the Mermaid diagram for your docs and the pseudocode skeleton to start your implementation. FAQ: Q: What are the core stages of a RAG pipeline? A: Load documents, split them into chunks, embed each chunk, store vectors, retrieve the top matches for a query, optionally rerank, then generate an answer with the retrieved context. The first four run at ingest time; retrieval and generation run per query. Q: When do I need a reranker? A: Add a reranker when top-k vector results contain near-misses. A cross-encoder reranker re-scores the retrieved chunks against the query for higher precision, at extra latency and cost — worth it for high-stakes answers. Q: How do I choose chunk size and top-k? A: Smaller chunks (200-500 tokens) improve precision; larger chunks preserve context. Start around top-k 5 and chunk 400, then tune against your eval set. The tool reflects your choices in the exported pseudocode. Q: Is the Mermaid output ready to paste? A: Yes. The diagram uses standard Mermaid flowchart syntax that renders in GitHub, Notion, and most docs tools. Copy it straight in. #### Retrieval Precision & Recall Calculator URL: https://geratools.com/retrieval-precision-recall Enter your retrieved chunk IDs and the ground-truth relevant IDs to compute precision, recall, F1 and MRR for RAG retrieval evaluation. No backend, no upload — everything is calculated in your browser. How to use: 1. Enter retrieved IDs: Paste the chunk or document IDs your retriever returned, in ranked order, separated by commas or new lines. 2. Enter relevant IDs: Paste the ground-truth set of IDs that are actually relevant to the query. 3. Read the metrics: The calculator returns precision, recall, F1 and mean reciprocal rank so you can judge retrieval quality at a glance. FAQ: Q: What is precision in retrieval? A: Precision is the fraction of retrieved items that are actually relevant — true positives divided by total retrieved. High precision means few irrelevant chunks make it into your context. Low precision wastes context tokens and can distract the model with off-topic passages. Q: What is recall in retrieval? A: Recall is the fraction of all relevant items that you successfully retrieved — true positives divided by total relevant. High recall means you are not missing important context. In RAG, low recall is dangerous because the model simply cannot answer correctly if the supporting passage was never retrieved. Q: What is the F1 score? A: F1 is the harmonic mean of precision and recall, giving a single balanced number between 0 and 1. It rewards systems that are good at both rather than excelling at one. Use it when you care about precision and recall roughly equally; weight differently if one matters more for your use case. Q: What is mean reciprocal rank (MRR)? A: MRR measures how high up the first relevant result appears. It is the reciprocal of the rank of the first relevant item (1 if it is first, 0.5 if second, and so on). It matters when only the top results feed the model, because a relevant chunk buried at rank 10 may never be used. Q: How many relevant IDs do I need to label? A: Even a small labelled set per query is useful, but more is better and more representative. Label every chunk you know is genuinely relevant for the query. Unlabelled relevant chunks count as false negatives and will unfairly depress recall, so be thorough. #### Vector Arithmetic Playground URL: https://geratools.com/vector-arithmetic-playground Run king - man + woman style vector arithmetic in your browser. Add, subtract, interpolate, or build analogies on embedding vectors and see the resulting vector with its magnitude and cosine similarity to the inputs. How to use: 1. Pick an operation: Choose analogy, add, subtract, or interpolate from the operation selector. 2. Enter your vectors: Type vectors A and B (and C for analogies) as comma-separated numbers or a JSON array. All vectors must share the same dimension. 3. Read the result: See the resulting vector plus its magnitude and cosine similarity to each input to understand where it landed in the space. FAQ: Q: What is the king - man + woman example? A: It is the classic word-embedding analogy showing that embeddings encode relationships as directions. Subtracting the man vector from king and adding woman lands near the queen vector, demonstrating that gender is roughly a consistent offset in the space. Q: What formats can I paste vectors in? A: You can use comma, space, or newline separated numbers, or a JSON array like [0.9, 0.1, 0.8]. All vectors in one operation must have the same number of dimensions or the tool will flag a mismatch. Q: What does interpolation do? A: Linear interpolation, or lerp, blends two vectors by a factor t — at t=0 you get A, at t=1 you get B, and values in between mix them. It is useful for exploring the path between two concepts in the embedding space. Q: Why show cosine similarity to the inputs? A: Cosine similarity tells you how close the result points in the same direction as each input vector, which is the standard relevance measure for embeddings. It helps you sanity-check that an analogy or blend landed where you expected. #### Vector Distance Suite URL: https://geratools.com/vector-distance-suite Calculate all common vector similarity and distance metrics at once — cosine similarity, dot product, Euclidean (L2) and Manhattan (L1) distance — from two pasted vectors. Useful for benchmarking RAG retrieval strategies without running code. How to use: 1. Paste both vectors: Enter vector A and vector B as comma-separated floats or JSON arrays of equal length. 2. Compare every metric: The tool computes cosine similarity, dot product, Euclidean distance, and Manhattan distance side by side. 3. Pick your metric: Use the comparison to decide which distance function best matches your vector database configuration. FAQ: Q: Which metric should I use for embeddings? A: Most text-embedding models are tuned for cosine similarity or dot product. If your vectors are normalised to unit length, cosine, dot, and Euclidean rank results identically, so the choice often comes down to what your vector database supports. Q: What is the difference between Euclidean and Manhattan distance? A: Euclidean (L2) is the straight-line distance — the square root of summed squared differences. Manhattan (L1) is the sum of absolute differences. L2 penalises large single-dimension gaps more heavily, while L1 is more robust to outliers. Q: Why is dot product not bounded? A: Unlike cosine similarity, the dot product scales with vector magnitude, so it has no fixed range. Models trained with dot-product objectives use it directly; otherwise normalise first or use cosine. Q: Is anything sent to a server? A: No. Every metric is computed locally in your browser. The vectors you paste are never uploaded or stored. ### Output Cleaning & Evaluation #### AI Fact-Check Claim Extractor URL: https://geratools.com/ai-fact-check-claim-extractor Paste AI-generated text and automatically identify and list all verifiable factual claims — statistics, dates, names, and citations — formatted as a checklist for manual verification before publication. Runs locally in your browser. How to use: 1. Paste the AI-generated text: Drop in the article, summary, or answer your model produced that you intend to publish or rely on. 2. Scan the extracted claims: The tool lists every sentence containing a statistic, date, named entity, quote, or citation — the parts most likely to be wrong if the model hallucinated. 3. Verify each item: Work through the checklist, confirming each flagged claim against a primary source, and copy the list to share with a reviewer. FAQ: Q: Why do AI factual claims need checking? A: Large language models generate fluent text that can include invented statistics, wrong dates, misattributed quotes, and fake citations. These hallucinations look confident and correct, so high-risk factual claims must be verified against primary sources before publication. Q: Does this tool verify the claims for me? A: No. It extracts and isolates the verifiable claims so a human can check them efficiently. Automated verification still requires trustworthy sources, which is why the output is a manual checklist. Q: What counts as a verifiable claim? A: Anything that can be confirmed true or false against evidence — numbers and percentages, specific dates, named people or organisations, direct quotes, and references or citations. Opinions and vague statements are not flagged. Q: Is my text sent anywhere? A: No. Extraction happens entirely in your browser with pattern matching and sentence analysis. Nothing is uploaded to a server or an AI provider. Q: How accurate is the extraction? A: It reliably catches sentences with numbers, dates, capitalised entities, quotation marks, and citation markers. It can miss subtly worded claims and may flag some non-claims, so treat it as a fast first pass, not a complete audit. #### AI Output Plagiarism Risk Advisor URL: https://geratools.com/ai-output-plagiarism-risk-advisor Describe the AI tool used and content domain to receive a plagiarism and IP risk assessment — covering memorization risk, near-verbatim reproduction indicators, and recommended human originality injection strategies. How to use: 1. Describe what you generated: Pick the AI tool, content domain, and intended use so the advisor can weigh the relevant memorization and reproduction risks. 2. Get your risk score: The advisor combines your inputs into a weighted risk level with the specific factors driving it. 3. Apply the mitigations: Follow the originality-injection steps suited to your risk level before publishing or shipping the content. FAQ: Q: How can AI output be plagiarism? A: Large models can reproduce memorized passages near-verbatim, especially for popular text, code, or quotes that appeared many times in training data. Using that output as your own without checking can infringe copyright or constitute plagiarism even if you did not intend it. Q: What raises memorization risk? A: Short, famous, or highly-repeated content (song lyrics, code snippets, canonical definitions, marketing taglines) is more likely to be reproduced verbatim. Long, specific, original prompts in niche domains carry lower risk. Q: Does this scan my actual text? A: No. This is a heuristic advisor based on the tool, domain, and use you describe. To check specific text, run it through a dedicated plagiarism detector and a web search for distinctive phrases. Q: Is AI-assisted content automatically plagiarism? A: No. Substantially edited, fact-checked, and reorganized AI output that reflects your own analysis is generally original. Risk concentrates in unedited, verbatim, high-memorization output used commercially. Q: What is originality injection? A: It is the practice of deliberately rewriting, restructuring, adding original analysis, and citing sources so the final work is meaningfully your own rather than a thin pass-through of model output. #### Chain-of-Thought Extractor URL: https://geratools.com/chain-of-thought-extractor Separate the reasoning trace from the final answer in LLM output. Detects common chain-of-thought formats — thinking tags, numbered steps, and reasoning cues — and isolates the clean answer. How to use: 1. Paste the LLM output: Drop in the full response, including any reasoning, thinking tags, or numbered steps. 2. Let it detect the format: The tool looks for thinking tags, numbered reasoning steps, and answer markers to split reasoning from the final answer. 3. Copy the clean answer: Take the isolated final answer for display to users, and keep the reasoning trace separately for logging or debugging. FAQ: Q: What chain-of-thought formats are detected? A: The tool recognizes XML-style thinking and reasoning tags, explicit answer markers like "Final answer:" or "Therefore", numbered or bulleted step lists, and common reasoning lead-ins such as "Let me think" or "Step 1". It uses whichever signal is present to split the trace from the conclusion. Q: Why separate reasoning from the answer? A: Users usually want the clean conclusion, not the model's scratch work, while developers want to log the reasoning for debugging and evaluation. Showing raw chain-of-thought to end users is also often discouraged by provider policies, so isolating the answer is a common production need. Q: What if there is no clear reasoning structure? A: When the tool finds no recognizable markers it treats the whole text as the answer and tells you no reasoning trace was detected. It never silently drops content, so you can trust that nothing is lost. Q: Does this work for reasoning model outputs? A: Yes for the visible portion. Some reasoning models hide their internal trace and only return a final answer plus a summary; this tool works on whatever text you paste, including thinking-tagged output, but it cannot recover a trace the API never returned. #### JSON Extractor from LLM Response URL: https://geratools.com/json-extractor-llm Scan a messy LLM response and extract every JSON object and array it contains — inside markdown fences, buried in prose, or across multiple code blocks. Each valid block is returned separately, pretty-printed, and copyable, all in your browser. How to use: 1. Paste the response: Drop the full LLM reply in, including any explanation text and markdown code fences around the JSON. 2. Extract the blocks: The tool scans the whole response and pulls out every balanced JSON object or array, validating each one. 3. Copy any block: Each valid block is pretty-printed and copyable on its own, so you can grab exactly the one you need. FAQ: Q: How does it find JSON inside prose? A: It scans the text for balanced brace and bracket spans, tracking string literals so braces inside strings do not confuse the matcher. Each candidate span is run through a real JSON parser, and only spans that parse are returned, so explanatory prose is ignored automatically. Q: Does it handle multiple JSON blocks? A: Yes. If a response contains several objects or arrays — for example one per code fence — each is extracted and shown separately so you can copy them individually rather than untangling one big string. Q: What if the JSON is slightly malformed? A: This tool extracts strictly valid JSON only. If a block has trailing commas, single quotes, or truncation, use the companion LLM JSON Repair tool first, then extract — or paste the repaired output here. Q: Is my data uploaded? A: No. Scanning and parsing run entirely in your browser. Nothing is sent anywhere or stored. #### LLM Response Comparison Table URL: https://geratools.com/llm-output-comparison-table Paste up to five LLM responses to the same prompt and compare them side by side in a structured table. Add custom rating columns for quality dimensions like accuracy or tone, score each response, and see word and character counts at a glance. How to use: 1. Paste the responses: Add up to five LLM responses to the same prompt, labelling each with its model or prompt variant. 2. Define rating dimensions: Add custom columns for the quality dimensions you care about, such as accuracy, tone, or completeness. 3. Score and compare: Rate each response on each dimension and read the totals plus word counts to pick a winner. FAQ: Q: How many responses can I compare? A: Up to five at once, which covers most A/B/C prompt experiments and small model bake-offs. Beyond five the table becomes hard to read, so trim to your top candidates first. Q: What are rating dimensions? A: They are the quality criteria you score each response against — for example accuracy, tone, conciseness, or instruction-following. You define your own, each scored from 0 to 5, and the tool sums them into a per-response total. Q: Does the tool grade the responses for me? A: No. Scoring is manual and human-driven, which is the point — you bring domain judgement the tool cannot. It only structures the comparison, tallies your scores, and shows objective stats like word count. Q: Is anything sent anywhere? A: No. Everything runs locally in your browser. The responses, labels, and scores never leave the page, so you can paste confidential or pre-release model output safely. Q: How should I weight the totals? A: The total is a simple sum across dimensions, treating each equally. If one dimension matters more (say accuracy over tone), interpret the totals with that priority in mind rather than trusting the raw sum blindly. #### LLM Output Grammar & Style Checker URL: https://geratools.com/llm-output-grammar-checker Browser-side grammar and style checking tuned to common LLM failure modes — passive-voice overuse, hedging chains, comma splices, AI filler phrases, repetitive sentence openers, and run-on sentences. No API key, fully private. How to use: 1. Paste the text: Drop the AI-generated text into the input box. Analysis runs instantly as you type. 2. Review flagged issues: Scan the list of warnings and notes — passive voice, hedging, AI filler, comma splices, repetitive openers, and long sentences. 3. Revise and recheck: Edit the weakest spots and watch the issue count fall. Use judgement; heuristics flag likely problems, not certainties. FAQ: Q: How is this different from a normal grammar checker? A: It targets the specific tells of AI-generated prose — overuse of passive voice, stacked hedges, filler phrases like "it's worth noting" or "delve into," and monotone sentence openers. A general checker catches typos, but these patterns are what make text read as machine-written. Q: Are the results always correct? A: No. The checks are pattern-based heuristics, not a full grammar parser, so passive-voice and comma-splice detection can produce false positives. Treat each flag as a prompt to look closer, not a definitive error. Q: Does my text get sent anywhere? A: No. All analysis runs locally in your browser with zero network requests, so your text never leaves your device. It is safe for confidential drafts. Q: Why flag repetitive sentence openers? A: LLMs often start consecutive sentences the same way — "The," "This," "Additionally" — which makes prose feel mechanical. Flagging openers that repeat three or more times nudges you toward more varied, human-sounding structure. #### Word Frequency & Diversity Analyzer URL: https://geratools.com/llm-output-word-frequency Analyze LLM output for word frequency, unique word count, type-token ratio, and lexical density. Surfaces repetitive or low-diversity text so you can spot bland, padded, or template-locked model responses fast. How to use: 1. Paste the text: Drop your LLM-generated output into the box. Everything runs locally in your browser. 2. Tune the stopword filter: Toggle common stopwords (the, a, and) on or off so the frequency table focuses on meaningful words. 3. Read the diversity metrics: Review the top words, unique-word count, type-token ratio, and lexical density to judge how varied the writing is. FAQ: Q: What is type-token ratio? A: Type-token ratio (TTR) is the number of unique words (types) divided by the total number of words (tokens). A higher ratio means more varied vocabulary. Because TTR falls as text gets longer, compare it only across passages of similar length. Q: What counts as lexical density? A: Lexical density here is the share of content words (everything that is not a common stopword) out of all words. Higher density usually signals more information-rich prose, while very low density can indicate filler or padding. Q: Why filter stopwords? A: Stopwords like "the", "of", and "and" dominate any raw frequency count and tell you little about the subject matter. Filtering them lets the genuinely meaningful, content-bearing words rise to the top of the table. Q: Does any text leave my browser? A: No. All counting and metric calculation happens entirely client-side in JavaScript. Nothing is uploaded, stored, or logged, so you can safely paste private or unpublished content. Q: How do I spot repetitive LLM output? A: Look for a low type-token ratio paired with a few words appearing far more often than the rest. Models that loop or pad tend to reuse the same connectors and phrases, which shows up clearly in the frequency table. ### Governance, Safety & Compliance #### AI API Rate Limit Security Advisor URL: https://geratools.com/ai-api-rate-limit-security-advisor Describe your AI API endpoint and receive recommended rate limit settings, abuse detection patterns, cost-cap mechanisms, and authentication requirements to prevent prompt injection, scraping, and denial-of-wallet attacks. How to use: 1. Describe the endpoint: Choose whether it's public or authenticated, the expected per-user request volume, and the cost per call to your AI provider. 2. Get the recommendations: The tool returns per-minute and per-day rate limits, a suggested daily cost cap, and the abuse controls that fit your risk profile. 3. Apply and monitor: Implement the suggested limits and detection patterns, then watch your metrics and tighten the numbers based on real traffic. FAQ: Q: What is a denial-of-wallet attack? A: It is an abuse pattern unique to metered AI APIs where an attacker drives up your provider bill rather than taking you offline. Because each call costs real money, a flood of expensive requests can be financially damaging even at modest request rates — which is why cost caps matter as much as rate limits. Q: Why are AI endpoints riskier than ordinary APIs? A: Each call can be expensive and slow, outputs can leak system prompts via prompt injection, and the endpoint is attractive for scraping model behaviour. Standard rate limiting is necessary but not sufficient; you also need cost caps and content-level controls. Q: Should public AI endpoints exist at all? A: They can, but only with strict limits, a hard daily cost cap, bot defences, and ideally a lightweight challenge. Unauthenticated access to a metered model is the highest-risk configuration, so the advisor tightens its recommendations sharply when there is no auth. Q: How are the suggested numbers derived? A: They start from your expected per-user volume and scale it by a safety multiplier, then cross-check against your cost per call so the daily cap stays within a sane budget. They are sensible defaults to start from, not guarantees — tune against real traffic. Q: Do rate limits stop prompt injection? A: No. Rate limits slow abuse but do not prevent a single crafted request from manipulating the model. You also need input/output filtering, system-prompt isolation, and not trusting model output as commands, which the advisor lists alongside the limits. #### AI Content Authenticity Disclosure Generator URL: https://geratools.com/ai-content-authenticity-disclosure Select the platform — LinkedIn, Twitter/X, news, academic journal, YouTube, or blog — and your AI involvement level to get a correctly formatted AI content disclosure statement that meets each platform's transparency expectations. How to use: 1. Choose the platform: Pick where the content will be published so the wording and format match that platform's norms. 2. Set the involvement level: Indicate whether the content is fully AI-generated, AI-assisted, or an AI draft you edited. 3. Copy the disclosure: Copy the generated statement and add it to your post, article, or description. FAQ: Q: Do I legally have to disclose AI-generated content? A: It depends on the context. The EU AI Act requires labelling of AI-generated or manipulated media, and many platforms and journals mandate disclosure. Even where it is not strictly required, transparency protects your credibility and reduces the risk of a policy violation. Q: How is academic disclosure different? A: Academic publishers such as those following ICMJE and COPE guidance require an explicit AI-use declaration, forbid listing AI as an author, and place full responsibility for the work on the human author. The generated academic statement reflects all three rules. Q: Does disclosing AI hurt my SEO or reach? A: Search engines reward helpful, transparent content rather than penalising AI use itself. A clear disclosure plus genuine human review supports trust signals like E-E-A-T, which generally helps rather than harms. Q: What counts as fully AI-generated versus AI-assisted? A: Fully AI-generated means the model produced the content with minimal human change. AI-assisted means you directed the work and the AI drafted parts. AI draft, human edited means the model produced a first pass that a person meaningfully revised. Pick the one that honestly describes your process. Q: Does this tool send my content anywhere? A: No. It only assembles a short disclosure statement locally in your browser from your platform and involvement choices. Your actual content is never entered or transmitted. #### AI Content Label HTML Generator URL: https://geratools.com/ai-content-label-html-generator Select the AI involvement level and generate a styled HTML label element you can embed directly in web pages to disclose AI-assisted content — with accessible markup, schema.org structured data, and customizable styling. How to use: 1. Choose involvement level and content type: Pick how much AI was involved — fully generated, assisted, edited, or human-written with AI tools — and the content type so the wording is accurate. 2. Pick a style and add the tool name: Choose a badge, banner, or subtle style, and optionally name the model or tool you used for extra transparency. 3. Copy the HTML and embed it: Copy the generated snippet and paste it into your page where the disclosure should appear. It carries accessible roles and schema.org data automatically. FAQ: Q: Why disclose AI involvement at all? A: Disclosure builds trust, and a growing number of platforms, advertisers, and regulators (including the EU AI Act transparency rules) expect or require it for AI-generated content. A clear label is cheaper than a credibility problem later. Q: What does the schema.org markup do? A: It wraps the label as a CreativeWork with a creditText property so search engines and AI crawlers can machine-read the disclosure. That improves how your transparency is understood beyond the visible text. Q: Is the label accessible? A: Yes. It uses role="note" with an aria-label so screen readers announce it as a disclosure note, and the emoji is marked aria-hidden so it is not read aloud as confusing characters. Q: Does naming the tool matter? A: It is optional but helpful. Naming the model or tool (for example GPT-4o or Midjourney) gives readers more context and is good practice for editorial transparency, though it is rarely strictly required. Q: Can I restyle the label after pasting? A: Yes. The styles are inline so it works anywhere, but you can move them into your own CSS class, change colors, or adjust spacing to match your site's design system. #### Content Safety Checker (BYO Key) URL: https://geratools.com/ai-content-safety-checker Paste content and the tool prompts your own OpenAI or Anthropic key for a structured safety audit across violence, hate, self-harm, sexual content, PII, bias, and misinformation, with severity flags and quoted evidence as JSON. Client-side; your key stays in your browser. How to use: 1. Add your API key: Pick OpenAI or Anthropic, choose a model, and paste your own key, which is used only for the direct request to the provider. 2. Set the severity threshold: Choose low to flag even mild concerns, medium for a balanced view, or high to surface only clear violations. 3. Check and review findings: Paste your content, run the tool, and read the JSON report — an overall verdict plus per-category findings with quoted evidence — then route flagged items to a human. FAQ: Q: Which categories does it screen? A: Violence and threats, hate and harassment, self-harm, sexual content, personal data (PII), bias and stereotyping, misinformation, and illegal or dangerous instructions. Each finding includes a severity, a short reason, and the quoted snippet that triggered it. Q: What does the severity threshold change? A: It tunes sensitivity. At a low threshold the model flags even mild or borderline concerns, useful for strict moderation. At high it only flags clear violations, reducing false positives. Medium balances the two. Pick the level that matches your tolerance. Q: Is this a substitute for a compliance review? A: No. It is a screening aid that surfaces likely issues quickly, but model moderation is imperfect — it misses things and over-flags others. Treat every flagged item as a prompt for human judgement, and never make a final policy or legal decision on the model output alone. Q: Where does my API key go? A: It stays in your browser tab and is sent directly to OpenAI or Anthropic with the request you trigger. It is never stored, logged, or routed through any Gera server, and refreshing the tab clears it. Q: Who pays for the API calls? A: You do, on your own provider account. Each check is one real API call billed at your usage rate. The tool itself is free — your only cost is the tokens consumed on your key. #### AI Contract Clause Library URL: https://geratools.com/ai-contract-clause-library Browse an offline library of standard AI-specific contract clauses — IP ownership of AI outputs, AI tool disclosure obligations, data protection in AI processing, liability for AI errors, and warranties — ready to copy into your agreements and adapt. How to use: 1. Filter by category: Choose IP, disclosure, data protection, liability, or warranties to narrow the library to the clauses you need. 2. Read the clause and its notes: Each clause has draft wording plus a note on when to use it and what to tailor for your situation. 3. Copy and adapt: Copy the clause text into your agreement and replace the bracketed placeholders. Always have a qualified lawyer review before signing. FAQ: Q: Can I use these clauses without a lawyer? A: These are educational drafting starting points, not legal advice. Contract law varies by jurisdiction and the right wording depends on your specific deal. Always have a qualified lawyer review and adapt any clause before you rely on it. Q: Who owns the output of a generative AI tool? A: It depends on the tool's terms, your jurisdiction, and the contract. Many AI providers assign output rights to the user, but copyright in purely AI-generated work is contested in several jurisdictions. An explicit IP clause avoids leaving this to default rules. Q: Why include an AI disclosure clause? A: A disclosure clause requires a party to tell the other when AI was materially used to produce a deliverable. It supports transparency, helps allocate liability for AI errors, and is increasingly expected by clients and regulators. Q: Does this tool store anything I copy? A: No. The clause library is bundled in the page and runs entirely in your browser. Nothing you view or copy is uploaded or saved. #### AI Data Residency Checker URL: https://geratools.com/ai-data-residency-checker Select your AI provider, subscription tier, and required data residency region to check whether the provider can meet your data sovereignty requirements — covering prompt storage, training use, and backup location. How to use: 1. Select provider and tier: Choose your AI provider and the subscription tier you are on or considering. 2. Choose your required region: Pick the data residency region your organization needs (EU, US, UK, or other). 3. Read the verdict: The checker shows whether the provider can keep data in your region on that tier, with notes on storage, training, and backups. FAQ: Q: Why does data residency depend on the subscription tier? A: Regional data residency, zero-retention modes, and signed DPAs are almost always enterprise or platform features (for example Azure OpenAI or a provider's enterprise plan), not consumer-tier features. A free or individual plan typically processes data wherever the provider chooses, so the tier is decisive. Q: Is "data residency" the same as "GDPR compliance"? A: No. Data residency is about where data is physically stored and processed. GDPR compliance is broader — it also covers lawful basis, data-subject rights, and a signed Data Processing Agreement. Keeping data in the EU helps but does not by itself make processing GDPR-compliant. Q: Does keeping prompts in my region stop the provider training on them? A: Not necessarily — region and training are separate settings. A provider may store data in your region yet still use it for training unless you are on a tier that excludes training. The checker notes the training position separately from the storage region. Q: What about backups and abuse-monitoring copies? A: Even with regional storage, transient copies can exist for abuse monitoring or backups. Enterprise tiers with zero data retention minimize this. Where it matters, confirm the provider's stated backup region and retention window in writing. Q: Is this checker authoritative for a compliance decision? A: No. It is a directional guide to help you ask the right questions. Provider offerings change frequently and vary by contract. Always confirm current residency commitments in your signed agreement before relying on them. #### AI Disclosure Label Generator URL: https://geratools.com/ai-disclosure-label-generator Select your content type, the AI tool you used, and how involved AI was, and get a ready-made disclosure label aligned with emerging EU AI Act, FTC, and platform transparency expectations — in short, standard, and formal variants you can embed in any publication. How to use: 1. Describe the content: Choose what you made — article, image, code, report — name the AI tool, and pick how much of the work AI did. 2. Pick a label style: Choose a short badge, a standard sentence, or a formal statement depending on where the label will appear. 3. Copy and embed: Copy the generated label and place it near your content. Use the plain-text or HTML version as needed. FAQ: Q: Am I legally required to disclose AI use? A: It depends on your jurisdiction, platform, and content type. The EU AI Act introduces transparency obligations for certain AI-generated and manipulated content, several platforms require disclosure, and the FTC expects honesty in advertising. This tool helps you write a clear label, but you should confirm your specific obligations. Q: What does 'level of AI involvement' change? A: It tunes the wording so the label is accurate. "AI-assisted" suits human work edited or aided by AI, while "AI-generated" suits content produced primarily by a model with light human review. Overclaiming or underclaiming both undermine trust. Q: Why offer short, standard, and formal versions? A: Different surfaces need different lengths. A short badge fits an image caption or byline, a standard sentence fits a blog footer, and a formal statement fits a report's methodology section or a regulated publication. Q: Does this guarantee EU AI Act compliance? A: No. It produces a clear, good-faith disclosure aligned with the spirit of current transparency rules, but it is not legal advice. For high-risk or regulated contexts, have counsel confirm the exact wording and placement you need. Q: Is my input sent anywhere? A: No. The label is assembled entirely in your browser from your selections. Nothing is uploaded or stored. #### AI Red Teaming Report Template URL: https://geratools.com/ai-red-teaming-report-template Generate a structured red team exercise report template — covering scope definition, attack categories tested, findings classification by severity, exploitation evidence format, and remediation recommendation structure, ready to copy into your security docs. How to use: 1. Define the engagement: Enter the system name, the red team scope, and select which attack categories you tested. 2. Generate the template: The tool produces a structured Markdown report with a severity-classified findings section and evidence format. 3. Fill in findings and export: Copy the Markdown, document each finding with evidence and remediation, then share with stakeholders. FAQ: Q: What is AI red teaming? A: AI red teaming is adversarial testing of an AI system — deliberately probing for prompt injection, jailbreaks, data leakage, harmful outputs, and abuse — to find weaknesses before attackers do. The report captures scope, findings, and fixes. Q: How should findings be classified? A: Use a consistent severity scale — critical, high, medium, low — based on impact and exploitability. Critical means reliable exploitation with serious impact (data exfiltration, RCE via tools); low means a minor or hard-to-reproduce issue. Q: What evidence should each finding include? A: A reproducible proof of concept: the exact prompt or input, the observed output, the conditions, and the success rate across attempts. Reproducibility is what separates a finding from a hunch. Q: Why include a scope section? A: Scope defines what was and was not tested, the rules of engagement, and any constraints. Without it, readers cannot tell whether a clean result means "secure" or "not tested", which is the most common reporting failure. Q: Does this tool transmit anything? A: No. The report is generated locally in your browser from your inputs. Nothing is uploaded, so you can document sensitive engagements safely. #### AI Safety Incident Log Template URL: https://geratools.com/ai-safety-incident-log-template Generate a structured AI safety incident log template for ongoing organizational tracking — capturing incident type, severity, affected users, root cause, remediation steps, and recurrence prevention for audit and governance purposes. How to use: 1. Set your organization context: Choose your organization type and list the AI systems you monitor. These tailor the fields and example entries to your environment. 2. Pick the columns you need: Toggle severity scales, affected-user counts, and root-cause fields on or off so the log matches your governance process without unused columns. 3. Copy the template: Copy the generated Markdown table or CSV header into your incident tracker, wiki, or spreadsheet and start logging from the first incident. FAQ: Q: What should an AI safety incident log capture? A: At minimum it should record what happened, when, severity, who or how many were affected, the suspected root cause, the remediation taken, and a recurrence-prevention action. Consistent fields make patterns visible across many incidents. Q: How is an AI incident different from a normal software bug? A: AI incidents often involve probabilistic behaviour — a harmful output, a biased decision, a hallucination, or an unsafe refusal — that may not reproduce deterministically. Logging the prompt, model version, and context is essential because you cannot always re-run the exact failure. Q: Who should own the incident log? A: Typically a named responsible-AI or risk owner maintains it, with engineering and product feeding entries. For regulated or public-sector use, the log often feeds an audit trail and may be disclosable, so keep entries factual and dated. Q: Does this tool store my incident data? A: No. It only generates a blank template structure in your browser. Nothing you type and nothing you log later is uploaded or stored by this tool. #### Sovereign AI Stack Advisor URL: https://geratools.com/ai-sovereign-stack-advisor Describe the AI tool you use and your sovereignty constraints to get recommended self-hostable or privacy-preserving alternatives across LLMs, image generation, speech-to-text, and embeddings — with hosting effort and trade-off notes. How to use: 1. Pick the tool you use today: Choose the proprietary AI tool you want to replace — chat LLM, image generation, transcription, or embeddings. 2. Set your constraints: Choose your hosting constraint, from fully air-gapped on-prem to EU/data-residency cloud. 3. Review the alternatives: Get matching open or self-hostable options with hosting effort, hardware needs, and the trade-offs to expect. FAQ: Q: What does a sovereign AI stack mean? A: It means running AI under your own control — self-hosted on your hardware, or on infrastructure in a jurisdiction you choose — so prompts and data never leave your boundary and aren't used to train someone else's model. It trades convenience for control, privacy, and data residency. Q: Are open models as good as proprietary ones? A: For many tasks, yes. Strong open-weight LLMs are competitive with mid-tier proprietary models for summarization, classification, and RAG. The gap is narrower than it was, but the very largest frontier models still lead on the hardest reasoning and coding tasks. Q: What hardware do I need to self-host an LLM? A: A quantized 7-8B model runs on a modern laptop or a single 16GB+ GPU. 70B-class models need a high-VRAM GPU (or several) or an Apple Silicon machine with a lot of unified memory. Smaller models cover most production tasks at far lower cost. Q: Is self-hosting actually cheaper? A: It depends on volume. At low volume, paying per API token is cheaper than running a GPU 24/7. At high, steady volume, self-hosting can cost less per token and gives fixed, predictable spend plus full data control. #### AI Watermark & Detection Explainer URL: https://geratools.com/ai-watermark-explainer Interactive explainer of AI content watermarking — statistical text watermarks, steganographic image embeds and C2PA metadata — with a worked demonstration of how detection works and where it reliably fails. How to use: 1. Pick a content type: Choose text or image to see the watermarking techniques that apply and how detection works for each. 2. Run the demonstration: Use the interactive demo to see how a statistical text watermark biases token choices, or how metadata can be read and stripped. 3. Read the limitations: Review the honest list of what watermarking and detection cannot do, so you do not over-trust a detector result. FAQ: Q: Can AI-generated text be detected reliably? A: Not reliably from the text alone. Statistical classifiers have high error rates, and any watermark survives only until the text is paraphrased or lightly edited. Treat detector output as a weak signal, never proof. Q: What is a statistical text watermark? A: It is a method where the model subtly biases its random token choices toward a secret pattern (a green-list of tokens). A detector that knows the key can spot the statistical skew. Paraphrasing or heavy editing destroys it. Q: What is C2PA? A: C2PA (Coalition for Content Provenance and Authenticity) is an open standard that attaches cryptographically signed metadata describing how a piece of media was created and edited. It proves provenance when present but can be stripped by re-saving or screenshotting. Q: What is SynthID? A: SynthID is Google DeepMind's watermarking system that embeds an imperceptible signal into AI-generated images, audio and text. The signal survives many common edits better than metadata, but it is provider-specific and not universal. Q: Can watermarks be removed? A: Yes, with effort. Metadata is trivially stripped by re-saving. Statistical text watermarks fall to paraphrasing. Robust image watermarks resist many edits but can degrade under heavy transformation, cropping or regeneration. #### AI Watermark & Artifact Removal Guide URL: https://geratools.com/ai-watermark-removal-guide Step-by-step guide for using Stable Diffusion inpainting to remove watermarks, stray text, and JPEG compression artifacts from images. Pick your artifact type, image type, and model to get recommended denoising, mask blur, padding, and step settings. How to use: 1. Select what you are removing: Choose the artifact type, image type, and which model you have. The tool tailors the denoising and mask settings to that combination. 2. Mask the artifact with margin: In your inpaint UI, paint over the watermark or artifact plus a small surrounding margin so the model has context to reconstruct from. 3. Apply the recommended settings: Set the suggested denoising strength, mask blur, and only-masked padding, then run. Repeat with a fresh mask if a faint ghost remains. FAQ: Q: What denoising strength should I use to remove a watermark? A: For solid logos and text on photos, 0.6-0.7 denoising regenerates the masked area enough to replace the watermark. For illustrations, 0.5-0.6 is usually enough. Lower values leave traces; higher values may change the underlying content too much. Q: Why use 'Inpaint only masked' instead of whole image? A: 'Only masked' crops to the masked region and inpaints it at full resolution, giving sharper reconstruction of small areas like a corner watermark. Whole-image inpainting downsamples the region and produces softer results. Q: How do I fix JPEG compression artifacts? A: Treat them differently from watermarks. Use a low denoising strength (around 0.3) so you smooth blockiness without regenerating content, and pair it with an upscaler at 0.2-0.3 denoise. High denoise on compression artifacts changes the image rather than cleaning it. Q: Is it legal to remove watermarks? A: Removing a watermark from an image you do not own or have a license to use can infringe copyright and may violate the source's terms. This guide is for cleaning your own AI generations and licensed assets. Always confirm you have the right to edit and use the image. #### Credit Card Number Masker URL: https://geratools.com/credit-card-masker Detects Luhn-valid credit and debit card numbers across all major networks — Visa, Mastercard, Amex, Discover, JCB, Diners — and replaces each with a masked version showing only the last four digits before you share text with an AI or paste it into a ticket. How to use: 1. Paste your text: Drop the message, log, or transcript that may contain card numbers into the input box. 2. Let the Luhn check run: The tool finds digit sequences, validates them with the Luhn algorithm, and identifies the card network so it only masks real card numbers. 3. Copy the masked output: Copy the cleaned text where each card shows only its last four digits. Nothing leaves your device. FAQ: Q: How does it avoid masking random numbers? A: Every candidate sequence of 13 to 19 digits is validated with the Luhn checksum and matched against known network prefixes. Numbers that fail the checksum — like order IDs or phone numbers — are left untouched, which sharply cuts false positives. Q: What does the masked output look like? A: Each detected card is replaced with its network name and the last four digits, for example "Visa ****1111". This keeps the text readable and lets you reconcile records without exposing the full PAN. Q: Which networks are recognised? A: Visa, Mastercard, American Express, Discover, JCB, and Diners Club, based on standard issuer identification number prefixes and lengths. Cards from unrecognised networks that still pass Luhn are masked generically. Q: Is this PCI-compliant redaction? A: It is a useful safeguard, but PCI DSS compliance is about your whole environment, not one tool. Use this to avoid pasting full card numbers into AI tools, and follow your organisation's PCI process for storage and transmission. Q: Is anything uploaded? A: No. Detection, the Luhn check, and masking all run locally in your browser. No card data is sent anywhere, logged, or stored. #### img2img Denoising Strength Advisor URL: https://geratools.com/img2img-denoising-guide Interactive guide showing how denoising strength (0.0–1.0) affects img2img output in Stable Diffusion — low values keep the original structure, high values allow creative freedom. Pick a transformation goal and source type for a recommended range. How to use: 1. Choose your transformation goal: Select what you want to do — subtle touch-up, style transfer, or a full creative reimagining. The bigger the change, the higher the denoising strength. 2. Pick your source image type: Tell the tool whether you are starting from a photo, a rough sketch, or an existing AI render. Sketches usually need more denoising than finished photos. 3. Read the recommended range: The advisor returns a denoising strength range plus a starting value to type into the img2img tab. Generate, then nudge up or down by 0.05 until it looks right. FAQ: Q: What does denoising strength actually control? A: It sets how much noise is added to your source image before the model re-denoises it. At 0.0 the output is identical to the input; at 1.0 the image is fully noised and the result ignores the original almost entirely. Q: Why does my img2img output look unchanged? A: Your denoising strength is too low — typically below 0.3. The model only repaints the noise it added, so a low value preserves nearly all the original pixels. Raise the strength to give the model room to change the image. Q: What is a safe default to start with? A: 0.5 is a sensible middle ground for most edits. It keeps the overall composition and pose while letting the model restyle colours, textures and details. Adjust from there based on how much change you want. Q: Does denoising strength affect generation speed? A: Indirectly. The number of actual sampling steps run is roughly steps × denoising strength, so a lower strength finishes faster. Some UIs show this as the "effective steps" for the img2img pass. #### SD CFG Scale Advisor URL: https://geratools.com/sd-cfg-scale-guide Free Stable Diffusion CFG scale advisor. Pick your model type and prompt style, drag the CFG slider from 1 to 30, and see what each value does to prompt adherence vs creativity with a recommended range — all in your browser. How to use: 1. Pick your model and prompt style: Choose SD 1.5, SDXL or a turbo/lightning model, then say whether your prompt is short and loose or long and detailed. 2. Read the recommended range: The advisor shows a recommended CFG band for that combination and flags when you are above or below it. 3. Move the slider to learn: Drag the CFG slider from 1 to 30 and watch the description explain the trade-off between prompt adherence and creativity at each value. FAQ: Q: What does CFG scale actually do? A: CFG (classifier-free guidance) scale controls how strongly the model is pushed toward your prompt versus its own learned priors. Low values let the model wander and stay creative; high values force literal prompt adherence but can oversaturate or distort. Q: What is a good default CFG scale? A: For SD 1.5 the common sweet spot is 6–9, and for SDXL it is roughly 5–8. Turbo, Lightning and LCM models are tuned for very low guidance, usually 1–2. Q: Why does a high CFG scale burn the image? A: Pushing guidance too high overshoots the prompt and amplifies contrast and saturation until the image looks fried, with halos and blown highlights. If that happens, lower CFG or raise the step count. Q: Is anything sent to a server? A: No. The advisor is fully client-side. Your selections never leave your browser and no image is generated here. ### Business & Workflow Builders #### AI Automation Opportunity Scanner URL: https://geratools.com/ai-automation-opportunity-scanner Paste a role description or task list and the scanner tags each task with automation potential — high, medium, or low — plus a suggested category of AI tool, so you can see where AI fits in a job before you invest. How to use: 1. Paste your tasks: Enter a job title and a list of tasks or paste a full job description, one task per line. 2. Scan for potential: The tool tags each task high, medium, or low for AI automation and names a tool category. 3. Act on the high tags: Start with the high-potential tasks and the suggested tool type for each. FAQ: Q: How does the scanner classify each task? A: It matches the wording of each task against signals for automatable work — verbs like write, draft, summarise, classify, schedule, and extract score high, while verbs implying judgement, negotiation, or physical action score low. The richer your phrasing, the more accurate the tag. Q: What do the three levels mean in practice? A: High means current AI can do most of the task with light review. Medium means AI can assist or draft but a person must finish or decide. Low means the task needs human judgement, presence, or accountability and should stay manual, with AI at most preparing inputs. Q: Why does it suggest a tool category instead of a product? A: Naming a category — such as a chat LLM, a transcription tool, or a document-extraction model — keeps the advice durable as specific products change, and points you to the right type of solution to evaluate without endorsing one vendor. Q: Can I paste a whole job description? A: Yes. Paste the responsibilities section with one task per line for the cleanest results. The scanner reads each line independently, so breaking a dense paragraph into separate tasks gives you a more useful per-task breakdown. Q: Is anything I paste sent to a server? A: No. The analysis runs entirely in your browser using local keyword logic. Nothing you paste is uploaded, so it is safe for internal or confidential role descriptions. #### AI Capability Matrix URL: https://geratools.com/ai-capability-matrix A filterable matrix mapping leading LLMs to their capabilities — code generation, image input, audio, function calling, web search, long-context documents and deep reasoning. Select the features you need and instantly see which models qualify. How to use: 1. Select required capabilities: Tick the features your project needs — code, vision, audio, function calling, web search, long context or deep reasoning. 2. Optionally filter by provider: Restrict the matrix to one provider if you are committed to a vendor, or leave it on All. 3. Read the qualifying models: The table shows only models that support every capability you selected, with a checkmark grid so you can see the full feature spread. FAQ: Q: How does the filtering work? A: It is an AND filter. A model only appears if it supports every capability you tick. If nothing matches, relax a requirement — few models cover every feature at once. Q: What does function calling mean? A: Function calling (tool use) lets the model return structured calls to functions you define, so it can fetch data or take actions. It is the foundation of agentic and tool-augmented apps. Q: Why do some flagships lack web search? A: Built-in web search is a platform feature, not just a model property — it depends on the API tier and product surface. The matrix marks the common API availability; verify the exact tier in provider docs. Q: Does this tool call any API? A: No. It is a static reference rendered in your browser. Selecting capabilities filters a local dataset with no network requests. #### AI-Assisted Decision Matrix Builder URL: https://geratools.com/ai-decision-matrix-builder Build a weighted decision matrix by defining options, criteria, and importance weights; the tool computes the winning option live and generates an AI prompt that narrates the trade-offs and a recommendation. How to use: 1. List your options: Enter the choices you are deciding between, one per line. 2. Define weighted criteria: Add the criteria that matter and set an importance weight for each from 1 to 10. 3. Score and review: Score each option against each criterion; the tool computes the weighted winner and builds a prompt that explains the trade-offs. FAQ: Q: How is the weighted score calculated? A: Each option's score on a criterion is multiplied by that criterion's weight, and the products are summed. The option with the highest total wins. Weights are normalised in the display so you can see each criterion's share of the decision. Q: What scoring scale should I use? A: A 1 to 5 or 1 to 10 scale works well — just be consistent across all cells. The absolute numbers do not matter as much as keeping them comparable, because the matrix is about relative trade-offs, not precision. Q: Why generate an AI prompt as well as a number? A: The number tells you the winner; the prompt makes the model narrate why — which criteria decided it, where the result is close, and what would have to change to flip it. That narrative is what you actually present to stakeholders. Q: What if two options tie? A: A near-tie is a signal that your criteria or weights are missing something. Add a tie-breaking criterion, or run the generated prompt, which is instructed to call out close results and suggest the decisive factor to investigate. Q: Is my data uploaded? A: No. All scoring and weighting happens in your browser, and the prompt is assembled locally. Nothing you enter is sent anywhere until you choose to paste it into your own LLM. #### AI Data Protection Impact Assessment (DPIA) Template URL: https://geratools.com/ai-dpia-template Describe your AI system's data processing activities and receive a pre-filled DPIA template covering necessity assessment, risk identification, mitigation measures, and DPO consultation triggers under GDPR Article 35. Exports Markdown. How to use: 1. Describe the processing: Enter the processing purpose, the data types involved, the categories of data subjects, and whether automated decisions are made. 2. Review the risk triggers: The template highlights Article 35 high-risk triggers your description matches, such as automated decision-making, large-scale processing, or special-category data. 3. Copy the pre-filled DPIA: Take the structured Markdown template, complete the remaining narrative sections with your specifics, and route it to your DPO for review. FAQ: Q: When is a DPIA legally required? A: Under GDPR Article 35 a DPIA is mandatory when processing is likely to result in a high risk to individuals — for example systematic automated decision-making with legal effects, large-scale special-category data, or systematic monitoring. AI systems frequently hit one or more of these triggers. Q: Does this tool produce a finished DPIA? A: No. It produces a structured starting template pre-filled from your inputs and flags the high-risk triggers you match. You still complete the narrative risk analysis and have it reviewed by a qualified data protection officer. Q: What does the necessity assessment cover? A: It documents why the processing is necessary and proportionate to the purpose, and whether a less intrusive option exists — the core Article 35 question of whether the high-risk processing is justified at all. Q: Is my input sent anywhere? A: No. The template is generated entirely in your browser. Nothing about your processing activities is uploaded to a server. Q: Who should sign off the final DPIA? A: The data controller is accountable, and where one is appointed the DPO must be consulted. For residual high risks that cannot be mitigated, you may also need to consult your supervisory authority before processing begins. #### AI in Employment Decisions Checklist URL: https://geratools.com/ai-employment-decision-checklist Walk through a compliance checklist for using AI in employment decisions covering EU AI Act high-risk requirements, EEOC and NYC Local Law 144 bias-audit duties, GDPR Article 22 rights, human oversight, and explainability for AI-assisted HR. How to use: 1. Set your HR process and system: Choose whether the AI informs hiring, promotion, performance, or termination, and name the system so the checklist is framed for it. 2. Select your jurisdiction: Pick the EU, US, UK, or all. The checklist filters to the safeguards that apply where you operate. 3. Work through the safeguards: Tick what is in place. Any unmet critical safeguard flags the deployment as non-compliant until you resolve it. FAQ: Q: Is AI in hiring high-risk under the EU AI Act? A: Yes. Annex III of the EU AI Act classifies AI used for recruitment, candidate filtering, promotion, and termination as high-risk. That triggers obligations including risk management, data governance, human oversight, transparency, and record-keeping before the system can be deployed. Q: Can an AI make a hiring decision on its own? A: Not for legally significant decisions in the EU and UK. GDPR Article 22 gives individuals the right not to be subject to solely automated decisions with significant effects, so a human must be able to review and override the AI's recommendation. Q: What does NYC Local Law 144 require? A: Employers using an automated employment decision tool for candidates in New York City must have an independent bias audit conducted and published, and must notify candidates that the tool is used and what it assesses. It is one of the strictest US-level disclosure regimes. Q: Why is explainability a legal requirement here? A: Both GDPR and the EU AI Act require that affected people can understand the main factors behind a decision and contest it. If you cannot explain in plain language why a candidate was screened out, you cannot meet the transparency and contestability obligations. Q: Is this checklist legal advice? A: No. It maps common obligations across the EU AI Act, GDPR, EEOC guidance, and NYC Local Law 144 to help you structure your compliance work. A qualified employment and data-protection lawyer should review any live deployment. #### AI Incident Evidence Preservation Checklist URL: https://geratools.com/ai-evidence-preservation-checklist Work through a forensic evidence preservation checklist after an AI safety incident — covering prompt logs, model version records, output caches, user session data, and system configuration snapshots for investigation. How to use: 1. Describe the incident: Select the incident type and which systems were involved so the checklist surfaces only the evidence sources that apply to your situation. 2. Preserve each source: Work down the prioritised list, freezing logs, snapshotting configuration, and exporting session data before retention windows expire. 3. Export the record: Copy the completed checklist with timestamps for your chain-of-custody file or incident report once each item is secured. FAQ: Q: Why preserve evidence before investigating? A: AI logs are frequently subject to short retention windows and rolling caches that overwrite themselves within hours. If you investigate first, the most diagnostic evidence — the exact prompt, the model version, the raw output — may already be gone. Preserve first, analyse second. Q: What evidence is unique to AI incidents? A: Beyond ordinary application logs you need the exact prompt and system prompt, the model name and version, sampling parameters like temperature, any retrieval context fed in, and the raw model output before post-processing. These determine whether the behaviour is reproducible. Q: Does this guarantee admissibility in a legal proceeding? A: No. This checklist helps you preserve the technical artifacts and maintain a basic chain of custody, but formal admissibility depends on jurisdiction and process. For litigation-grade preservation, involve legal counsel and a qualified forensic specialist early. Q: How fast do I need to act? A: Treat the first hour as critical. Provider-side logs, ephemeral caches, and in-memory session state can disappear quickly. Issue a litigation hold or retention freeze to your provider and internal teams as the very first action. Q: Is my progress saved? A: Yes, your ticks are stored locally in your browser so a refresh does not lose them, and nothing is sent to a server. The checklist itself is informational and is not a substitute for professional incident-response advice. #### AI in Your Industry Glossary Builder URL: https://geratools.com/ai-industry-glossary-builder Pick your industry, audience level, and term count, and the tool builds a prompt that makes an LLM generate a plain-English AI glossary — hallucination, RAG, agents, fine-tuning and more — with examples specific to your field. How to use: 1. Choose your industry: Select the field whose examples and analogies the glossary should use so definitions feel relevant. 2. Set audience level and term count: Pick whether readers are beginners or technical, and how many terms you want covered. 3. Copy the prompt: Paste the generated prompt into any LLM to produce a tailored AI glossary you can share. FAQ: Q: What terms does the glossary cover? A: The prompt asks for core AI concepts every professional now meets — hallucination, prompt, token, context window, RAG, fine-tuning, agent, embedding, model, and more — and asks the model to add any terms especially relevant to your industry. Q: Why tailor it to an industry? A: A generic definition of "RAG" means little to a lawyer or a nurse. Tailoring asks the model to ground each term in an example from your field, which makes the glossary far more useful for onboarding and training. Q: What does the audience level change? A: Beginner produces jargon-free, analogy-led definitions for non-technical staff. Technical produces precise definitions that assume familiarity with software concepts. Choose based on who will read it. Q: Can I use this to train my team? A: Yes. The output is designed as a shareable reference — paste it into a wiki, slide deck, or onboarding doc. Ask the model for a follow-up quiz to check comprehension. Q: Does the tool generate the glossary itself? A: No. It builds the prompt in your browser; you run it in your own LLM. That keeps the tool free and lets you pick whichever model you trust. #### AI Training Opt-Out Email Template Library URL: https://geratools.com/ai-opt-out-email-template Select an AI provider and the type of opt-out you need — training data use, conversation history, or model improvement — and get a ready-to-send email template with the required identifying information and a relevant legal basis cited. How to use: 1. Pick provider and opt-out type: Choose the AI provider and whether you want to opt out of training data use, conversation history, or general model improvement. 2. Fill in your details: Add your account email and (optionally) your name so the template includes the identifying information the provider needs to action the request. 3. Copy and send: Copy the generated email, paste it into your mail client, and send it to the provider's privacy or support address. FAQ: Q: Do these opt-out emails legally force a provider to comply? A: They invoke rights that may apply to you, such as the GDPR right to object to processing or the CCPA right to opt out. Whether a provider must comply depends on your jurisdiction and their role as controller or processor. Many also offer a settings toggle that is faster than email. Q: Should I use the in-app setting or an email? A: If the provider offers an in-product toggle (many now do), use it first — it is instant and auditable. Use the email when there is no toggle, when you want a written record, or when you are also requesting deletion of past data. Q: What legal basis should I cite? A: In the EU/UK, GDPR Article 21 (right to object) and Article 17 (erasure) are common; in California, the CCPA right to opt out and delete. The template cites a plausible basis, but tailor it to your actual jurisdiction. Q: Does this tool send the email or store my details? A: No. It only assembles the text in your browser. You copy it and send it yourself from your own email client — nothing is transmitted or stored by this tool. #### AI Project Charter Builder URL: https://geratools.com/ai-project-charter-builder Input your project name, goal, stakeholders, KPIs, and timeline, and the tool assembles a clean one-page AI project charter — scope, success metrics, owners, and milestones — ready to share with leadership. How to use: 1. Fill in the basics: Enter the project name, the problem it solves, and the primary goal in one sentence. 2. Add stakeholders, KPIs, and dates: List who owns and sponsors the work, the metrics that define success, and the start and target dates. 3. Copy the charter: Copy the generated one-page charter as Markdown and paste it into your doc, wiki, or leadership deck. FAQ: Q: What is an AI project charter? A: A charter is a one-page document that defines an AI initiative's purpose, scope, owners, success metrics, and timeline. It aligns stakeholders before work starts and gives leadership a single reference for what the project will and will not deliver. Q: Why do AI projects specifically need a charter? A: AI projects are easy to start and hard to scope, because expectations drift toward "magic" and data dependencies are often underestimated. A charter forces you to name a measurable goal, a baseline, and explicit non-goals, which is the most common gap in failed AI pilots. Q: Does the tool send my information anywhere? A: No. The charter is assembled entirely in your browser from the fields you enter. Nothing is uploaded, so you can safely include internal project details. Q: What KPIs should I include? A: Pick one or two metrics that move only if the project works — for example reduction in handling time, increase in qualified leads, or model accuracy against a labelled set. Always pair each KPI with the current baseline so the target is meaningful. Q: Can I edit the charter after generating it? A: Yes. The output is plain Markdown, so paste it anywhere and edit freely. Re-run the tool any time you change scope and replace the section that moved. #### AI Vendor Data Processing Agreement Checklist URL: https://geratools.com/ai-vendor-dpa-checklist Paste an AI vendor's Data Processing Agreement to check it against a GDPR Article 28 compliance checklist — flagging missing clauses on sub-processors, security measures, breach notification, deletion rights, audit access, and AI model training. How to use: 1. Paste the DPA text: Copy the full Data Processing Agreement from your AI vendor into the box. Everything is analysed locally in your browser. 2. Read the coverage report: The tool scans for each mandatory Article 28 clause and marks it present or apparently missing, separating critical clauses from secondary ones. 3. Investigate the gaps: For any clause flagged missing, search the contract under alternative wording and raise the gap with the vendor or your counsel. FAQ: Q: What is a Data Processing Agreement? A: A DPA is the contract required by GDPR Article 28 whenever a processor handles personal data on a controller's behalf. For AI vendors that means anyone whose API or tool sees your customers' or employees' data. Without a compliant DPA the processing itself can be unlawful. Q: Which Article 28 clauses are mandatory? A: Article 28(3) sets out a defined list — processing only on documented instructions, confidentiality, security measures, sub-processor controls, assistance with data-subject rights, breach notification, deletion or return on termination, and audit rights. All of these are treated as critical in this checklist. Q: Why does AI model training matter in a DPA? A: Many AI vendors reserve the right to use customer inputs to improve their models. If your data includes personal data, that is a new purpose that needs a lawful basis and should be contractually addressed. A clear no-training clause closes a common and serious gap. Q: Can keyword matching miss a clause that is actually present? A: Yes. The same obligation can be drafted with very different wording, so a missing flag means review, not a verdict. Treat the tool as a fast triage that tells you where to read the contract carefully. Q: Does my contract text leave my browser? A: No. All matching happens locally in JavaScript. The DPA text is never uploaded or stored anywhere. #### AI Writing Style Guide Builder URL: https://geratools.com/ai-writing-style-guide-builder Answer a few questions about tone, point of view, register, example sentences, banned words, and preferred framings, and the tool assembles a reusable brand voice system prompt you can prepend to any LLM writing session for consistent output. How to use: 1. Describe the voice: Enter the brand name, tone adjectives, point of view, and register. 2. Add examples and rules: Paste example sentences that sound right and list words to avoid or prefer. 3. Copy and reuse: Copy the generated system prompt and paste it at the start of every writing session for consistent output. FAQ: Q: Why build a reusable voice prompt instead of describing the voice each time? A: Re-describing your voice every session is inconsistent and slow, and small wording differences drift the output. A saved system prompt pins the voice once, so every draft starts from the same instructions and the brand sounds like one writer. Q: How important are the example sentences? A: Very. Adjectives like 'warm' or 'confident' are interpreted loosely, but real example sentences show the model the exact rhythm and word choice you mean. Two or three strong examples often do more than a paragraph of description. Q: What does the avoid list do? A: It tells the model never to use specific words or phrases — corporate clichés, competitor terms, or anything off-brand. Combined with a preferred-framings list (say 'members' not 'users'), it enforces vocabulary choices that adjectives alone can't. Q: Where do I paste the generated prompt? A: At the very start of a chat, as a custom instruction, or as a system prompt in an API call. The prompt ends by asking the model to confirm 'Voice loaded — ready.' so you know it took effect before you give the writing task. Q: Is anything I enter stored or sent? A: No. The prompt is assembled entirely in your browser. Your brand details and examples never leave your machine until you paste the result into your own LLM. #### Batch Image Generation Planner URL: https://geratools.com/batch-generation-planner Enter batch parameters — image count, resolution, steps, model, and hardware — to estimate total generation time, cloud credit cost, and whether local or cloud generation is the better choice for your job. How to use: 1. Enter your batch size and settings: Type how many images you need, the resolution, steps, and which model you are running. 2. Pick your hardware: Choose a local GPU or a cloud GPU tier so the planner can estimate throughput and cost. 3. Read the plan: See total time, cost, and a local-versus-cloud recommendation for your batch. FAQ: Q: How is total time estimated? A: The planner estimates seconds per image from the model, GPU, resolution, and step count, then multiplies by your image count. It is a planning estimate — real runs vary with sampler, VRAM headroom, and whether you batch images per call. Q: When is cloud cheaper than local? A: Cloud wins for occasional large bursts where you do not own a fast GPU, or when you need many images quickly and can rent a high-end card by the hour. If you generate constantly, owning a 3090/4090 amortises fast and local becomes far cheaper per image. Q: Does a higher step count always look better? A: No. Modern samplers plateau around 20–30 steps for most models; beyond that you mostly burn time and credits. Drop steps first when you need to cut a large batch's cost. Q: How do I cut the cost of a big batch? A: Lower resolution and upscale the keepers afterwards, reduce steps to the sampler's sweet spot, generate a small test batch to fix the prompt before committing, and batch multiple images per GPU call to amortise model load. #### Function-Calling JSON Schema Builder URL: https://geratools.com/json-schema-builder A visual editor to define a function or tool name, description, and typed parameters with required flags. Exports valid JSON Schema in both OpenAI function-calling and Anthropic tool-use formats, ready to paste into your API request. How to use: 1. Name your function: Enter a function name and a clear description the model will read to decide when to call it. 2. Add parameters: Add each argument with a name, type, description, and whether it is required. 3. Copy the schema: Switch between OpenAI and Anthropic formats and copy the valid JSON straight into your API call. FAQ: Q: What is the difference between the OpenAI and Anthropic formats? A: Both wrap the same JSON Schema parameters object. OpenAI nests it under type "function" with a "function" object, while Anthropic uses a top-level "name", "description", and "input_schema". This tool emits both from the same definition. Q: Why does the description matter so much? A: The model decides whether and how to call your tool based almost entirely on the function and parameter descriptions. Vague descriptions cause missed or malformed calls, so write them as if instructing a careful assistant. Q: What types are supported? A: string, number, integer, boolean, array, and object — the JSON Schema primitives that both OpenAI and Anthropic accept. Enum values can be added to string parameters to constrain the model to a fixed set. Q: Is the output valid JSON Schema? A: Yes. The generated parameters object is draft-2020 compatible JSON Schema with a properties map and a required array, which both providers consume directly. #### .jsonl Dataset Builder URL: https://geratools.com/jsonl-builder Free .jsonl dataset builder for LLM fine-tuning. Add prompt/completion pairs or chat messages arrays via a form, get live per-line validation against OpenAI's chat format, see your example count, and download a clean .jsonl file ready to upload. How to use: 1. Add training examples: For each example, fill in an optional system message, the user message, and the assistant response. Each one becomes a single chat-format line. 2. Watch live validation: The builder flags empty user or assistant fields and shows your running example count so you know when you have enough data to fine-tune. 3. Download the .jsonl file: Copy the generated content or download it as a .jsonl file with one valid JSON object per line, ready to upload to OpenAI's fine-tuning API. FAQ: Q: What format does the file use? A: It uses OpenAI's chat fine-tuning format: each line is a JSON object with a 'messages' array containing optional system, user, and assistant turns. This is the format the fine-tuning API expects for gpt-4o-mini and similar models. Q: How many examples do I need? A: OpenAI requires at least 10 examples to start a fine-tuning job, and recommends 50–100 high-quality examples for a meaningful improvement. The builder shows your count so you can track progress toward those thresholds. Q: Why one JSON object per line? A: JSONL (JSON Lines) puts one complete, independent JSON object on each line with no enclosing array. This lets training pipelines stream examples one at a time without loading the whole file into memory. Q: Is my data uploaded anywhere? A: No. Everything is built and validated locally in your browser. Your examples are never uploaded, stored or logged, and the download is generated on your device. #### Rate Limit & Throughput Planner URL: https://geratools.com/rate-limit-throughput-planner Given your TPM and RPM limits, calculate the maximum sustainable throughput, average response time budget, and recommended request queue depth for your workload. Fully client-side. How to use: 1. Enter your account limits: Type your tokens-per-minute (TPM) and requests-per-minute (RPM) ceilings from your provider dashboard. 2. Describe an average request: Enter the average prompt and completion tokens per call and your target P95 latency in seconds. 3. Read the safe throughput: See the binding limit, the maximum sustainable requests per minute, and the concurrency you can safely run. FAQ: Q: What is the difference between TPM and RPM? A: TPM caps total tokens (prompt plus completion) processed per minute; RPM caps the number of requests per minute. Whichever you hit first is your binding limit, which this tool identifies for you. Q: How is safe concurrency calculated? A: Concurrency is the safe requests-per-minute divided by 60, multiplied by the average latency in seconds (Little's Law: in-flight requests = arrival rate x time in system). That tells you how many parallel workers you can keep busy without exceeding the rate. Q: Why leave headroom below the limit? A: Bursts, retries, and token-count variance push you over a hard ceiling and trigger 429s. The planner applies a safety margin so a spike does not blow past the limit and cause cascading retries. Q: Does the completion token count really count against TPM? A: Yes. Most providers count prompt plus completion tokens toward TPM, and they reserve max_tokens up front. Setting a tight max_tokens lets you fit more requests inside the same TPM ceiling. Q: What if my limits change per tier? A: Re-enter the new TPM and RPM from your dashboard. Limits scale with usage tier, so re-plan whenever you are promoted to a higher tier or request a raise. ### Content Generators & Writing #### Email Tone Checker URL: https://geratools.com/ai-email-tone-checker Client-side tone analysis that scores your email across warmth, assertiveness, clarity, and politeness using linguistic signals, then flags risky phrasing and suggests rewrites — all in your browser, nothing uploaded. How to use: 1. Paste your email: Drop the draft email text into the box; it is analysed entirely in your browser. 2. Pick the intended tone: Tell the checker the tone you are aiming for so it can flag where the draft drifts. 3. Review the scores and flags: Read the warmth, assertiveness, clarity, and politeness scores, then act on the flagged phrases and rewrite suggestions. FAQ: Q: How does the tone analysis work without sending my email anywhere? A: It uses transparent linguistic heuristics that run in your browser — counting hedging words, intensifiers, politeness markers, sentence length, exclamation marks, and demanding phrasing. Nothing is uploaded; the analysis is fully client-side. Q: Is heuristic analysis as good as an LLM? A: It is faster, private, and deterministic, and it catches the most common tone problems — over-hedging, accidental bluntness, walls of text. For nuanced rewrites you can paste the same email into an LLM, but the checker gives you instant, free, offline feedback first. Q: What do the four dimensions mean? A: Warmth measures friendliness and rapport, assertiveness measures how directly you make requests, clarity measures how easy the email is to act on, and politeness measures softening and courtesy. A good email balances them for its purpose. Q: Why does a polite email sometimes score low on assertiveness? A: Excessive hedging ("just", "maybe", "if it's not too much trouble") reads as polite but buries the actual request. The checker flags this trade-off so you can keep the courtesy while making the ask unmissable. Q: Does it store my drafts? A: No. The email exists only in the page while you have it open. Refreshing or closing the tab discards it — nothing is saved or transmitted. #### JSON Schema → Human-Readable Docs URL: https://geratools.com/json-schema-docs-generator Paste a JSON Schema — such as an LLM tool or function-calling definition — and get a clean Markdown documentation page listing every parameter with its type, whether it is required, allowed values, defaults, and descriptions, ready to copy into your docs. How to use: 1. Paste your JSON Schema: Drop in a JSON Schema object — including the wrapper from an OpenAI or Anthropic tool definition if you have one. Invalid JSON is flagged immediately. 2. Generate the docs: The tool walks the schema's properties, including nested objects and arrays, and builds a Markdown parameter table with types, required flags, enums, and defaults. 3. Copy the Markdown: Copy the generated Markdown into your README, API reference, or internal wiki. It renders cleanly on GitHub and most docs platforms. FAQ: Q: What schema shapes does it accept? A: A plain JSON Schema object with a properties map, or a full LLM tool definition wrapper from OpenAI (function.parameters) or Anthropic (input_schema). The tool detects the wrapper and unwraps to the underlying schema automatically. Q: Does it handle nested objects and arrays? A: Yes. Nested object properties are documented with dotted paths, and array item types are shown including the element schema. This keeps deeply structured tool inputs readable without losing the hierarchy. Q: Why document tool schemas at all? A: When you expose function-calling tools to an LLM or to other developers, the parameter descriptions are part of the contract the model reads. Clear, human-readable docs catch missing descriptions and ambiguous types that would otherwise cause the model to call the tool incorrectly. Q: Is anything sent to a server? A: No. Parsing and rendering happen entirely in your browser, so you can document private internal tool schemas without exposing them. Nothing leaves the page. ### AI Glossary & Comparisons #### ADetailer Face & Hand Fix Guide URL: https://geratools.com/adetailer-settings-guide Get recommended ADetailer settings for fixing faces, hands, or full bodies in Stable Diffusion. Choose your fix target and model type to see the right detection model, confidence threshold, denoising strength, mask blur, and dilation. How to use: 1. Pick your fix target and model: Choose whether you are fixing faces, hands, or full bodies, and select SD 1.5, SDXL, or anime. The tool tailors every setting to that pair. 2. Set the detection model and confidence: Load the recommended YOLO detection model in ADetailer and set the confidence threshold so it reliably finds the target without false positives. 3. Apply denoising and mask settings: Enter the recommended denoising strength, mask blur, dilation, and only-masked inpaint size, then generate. ADetailer runs the fix automatically after the base image. FAQ: Q: What denoising strength is best for faces? A: Use 0.3-0.4 for faces. This is enough to fix distortion and add detail while keeping the face on-model and consistent with the original. Push toward 0.5 only when features are badly broken, since high denoise can change identity. Q: Why are hands harder to fix than faces? A: Hands need higher denoising (around 0.5-0.6) because fixing finger count and pose requires genuinely regenerating the region, not just refining it. Adding hand-positive prompts and a larger mask dilation helps, and a hand-refiner ControlNet handles the worst cases. Q: What detection model should I use? A: face_yolov8n for faces, hand_yolov8n for hands, and person_yolov8n-seg for full bodies. The 'n' (nano) models are fast and accurate enough for most images; larger variants help only when detection misses. Q: How does only-masked inpaint size affect quality? A: ADetailer crops the detected region and inpaints it at the specified resolution. Setting it to 512 (SD 1.5) or 1024 (SDXL) gives the model a high-res crop of the face or hand, producing much sharper detail than inpainting at the original small region size. #### AI Document Intelligence Comparison URL: https://geratools.com/ai-document-intelligence-comparison Reference matrix for document AI and OCR APIs covering extraction accuracy, supported formats, language coverage, prebuilt models, and price per page — AWS Textract, Azure Document Intelligence, Google Document AI, and more. How to use: 1. Set your needs: Choose your document type and approximate monthly volume, then filter by provider or budget to narrow the document AI services worth evaluating. 2. Compare the columns: Read across extraction accuracy, supported formats, language coverage, prebuilt models, and price per page to see which service fits your pipeline. 3. Sort to rank: Click any column header to sort ascending or descending so you can rank services by price per page, accuracy, or language coverage. FAQ: Q: What is document intelligence versus plain OCR? A: Plain OCR returns raw text from an image. Document intelligence (also called IDP) goes further — it extracts structured fields, key-value pairs, tables, and document layout, often with prebuilt models for invoices, receipts, IDs, and forms. Q: Which service is best for invoices and receipts? A: AWS Textract, Azure Document Intelligence, and Google Document AI all ship prebuilt invoice and receipt models with strong accuracy. Azure and Google also let you train custom extraction models for proprietary form layouts. Q: How is price per page calculated? A: Document AI is billed per page processed, and prebuilt or custom models cost more than raw OCR. Prices are list-price estimates and clearly labelled; tiered volume discounts and per-feature surcharges vary, so confirm in each provider's pricing page. Q: Can I extract data from handwritten documents? A: Yes, to varying degrees. Azure Document Intelligence and Google Document AI handle handwriting reasonably well on Latin scripts, while AWS Textract supports handwriting in English. Accuracy drops on poor scans, so always test on your real documents. #### AI Training Opt-Out Guide URL: https://geratools.com/ai-training-opt-out-guide Select the AI service you use and get exact step-by-step instructions to opt your account or organization out of using your data for model training, with direct deep-links to the relevant settings pages. How to use: 1. Pick your AI service: Choose the provider you want to opt out of, such as ChatGPT, Claude, Gemini, or Copilot. 2. Follow the numbered steps: Work through the exact clicks for that provider, using the deep-link to jump straight to the settings page. 3. Confirm and verify: Save the setting and re-check it later, since policy and UI changes can reset preferences. FAQ: Q: Does opting out delete data already used for training? A: Usually no. Opting out generally stops future use of your data for training but does not remove data already incorporated into models. To remove existing data, look for a separate data-deletion request in the same settings area. Q: Will opting out reduce the quality of the AI? A: No. Opting out of training affects whether the provider learns from your data, not the model you interact with. Your responses are generated by the same model either way. Q: Are business and API plans already opted out? A: Often yes. Many providers exclude API, business, and enterprise usage from training by default, so the opt-out steps mostly matter for consumer plans. The guide notes when a plan is excluded by default. Q: Can a setting reset itself? A: Yes. Provider UIs and policies change, new features can default to on, and signing into a new device or product can introduce new settings. Re-check your preferences periodically. Q: Is this guide official? A: No. It is an independent step-by-step reference. UIs change often, so if the steps no longer match, use the deep-link to reach the settings area and look for the equivalent toggle, or consult the provider's help center. #### Canny Edge Preprocessing Guide URL: https://geratools.com/canny-edge-prep-guide Guide to preparing Canny edge maps for ControlNet. Explains low threshold, high threshold, aperture size, and L2 gradient, and recommends settings by image type so your edge map captures the right detail density. How to use: 1. Pick your image type: Choose what the source image is — line art, a photo, or a detailed scene — since that drives sensible threshold ranges. 2. Set low and high thresholds: The low threshold controls weak-edge sensitivity and the high threshold controls strong-edge confirmation. Wider gaps capture more detail; higher values capture only bold edges. 3. Preview and refine: Generate the Canny map, check whether it has too many or too few edges, and nudge the thresholds before feeding it to ControlNet. FAQ: Q: What do the low and high thresholds actually do? A: Canny uses hysteresis. Pixels with a gradient above the high threshold are definite edges; pixels above the low threshold are kept only if connected to a definite edge. Raising the high threshold drops weak edges, while lowering the low threshold lets more faint detail through. Q: What thresholds should I start with? A: A common default is a low of 100 and a high of 200. For busy photos where you want only major contours, raise both (for example 150/300). For line art or sketches where you want every line, lower them (for example 50/150). Q: What is aperture size? A: Aperture size is the Sobel kernel used to compute gradients, usually 3, 5, or 7. A size of 3 is the standard and captures fine detail; larger apertures smooth the image first, producing thicker, fewer edges that suit noisy or high-resolution sources. Q: Should I enable L2 gradient? A: L2 gradient uses a more accurate Euclidean gradient magnitude instead of the faster L1 approximation. It produces slightly cleaner, more precise edges at a small speed cost. Enable it for final maps where edge accuracy matters; the default L1 is fine for quick iteration. #### AI Face Restoration Settings Guide URL: https://geratools.com/face-restoration-guide Pick a face-restoration model (GFPGAN, CodeFormer, or RestoreFormer) and a fidelity target to get recommended weight, blend strength, and step-by-step settings for Automatic1111 and ComfyUI. How to use: 1. Choose a restoration model: Pick GFPGAN for natural results, CodeFormer for heavy damage, or RestoreFormer for identity preservation. 2. Set your fidelity target: Slide between maximum quality (more invented detail) and maximum fidelity (closer to the original face). 3. Apply the recommended settings: Read the suggested weight and blend strength, then follow the Automatic1111 or ComfyUI steps shown. FAQ: Q: GFPGAN vs CodeFormer vs RestoreFormer — which should I use? A: GFPGAN gives the most natural, neutral cleanup. CodeFormer reconstructs heavily degraded or AI-mangled faces but can over-smooth at high weight. RestoreFormer best preserves the original identity, which matters for portraits of real people. Q: What does the CodeFormer weight actually do? A: CodeFormer's weight (often called fidelity, 0 to 1) trades quality for fidelity. Low values (0.2–0.4) maximise sharp invented detail; high values (0.7–1.0) stay closer to the input but restore less. There is no single right value — match it to how damaged the face is. Q: Why does my restored face look pasted on? A: That is usually 100% blend strength on a face whose lighting or grain differs from the scene. Lower the visibility/blend to 60–80% so the restored face mixes with the original texture, or run a light upscale pass afterwards. Q: Should I restore before or after upscaling? A: Restore first on the original-resolution face, then upscale the whole image. Restoring a small face and then enlarging it keeps the model working with the detail it was trained on; upscaling first can lock in artifacts the restorer then amplifies. #### AI Face Swap Workflow Planning Guide URL: https://geratools.com/faceswap-planning-guide Planning guide for AI face swap work. Recommends a tool (ReActor, FaceFusion, Roop) for your use case, sets source-image quality requirements and quality settings, and surfaces the consent and ethical guardrails you must clear first. How to use: 1. Define the use case: Pick what the swap is for — personal art, film VFX, or content creation. The tool flags consent requirements and recommends a fitting workflow. 2. Get the tool and settings: Based on your use case and skill level, it recommends ReActor, FaceFusion, or a Roop-based pipeline and lists baseline quality settings. 3. Clear the ethical checklist: Confirm consent, labeling, and platform-policy items before generating. The guide will not recommend a workflow until the hard guardrails are acknowledged. FAQ: Q: Do I need consent to swap someone's face? A: Yes, for any identifiable real person. Using someone's likeness without permission can violate privacy, publicity, and increasingly deepfake-specific laws. The guide treats consent as a non-negotiable gate, not an option. Q: What source image quality do I need? A: A sharp, well-lit, front-facing source at the highest resolution you have gives the best result. Matching the lighting direction and angle of the target shot matters as much as raw resolution for a believable swap. Q: Which tool should I use? A: ReActor (as a Stable Diffusion extension) is the most accessible for image work; FaceFusion is stronger for video and offers more enhancement controls; Roop-based pipelines suit scripted batch jobs. The guide picks based on your use case and skill level. Q: How do I avoid uncanny results? A: Match target and source lighting and angle, enable a face-restoration pass like GFPGAN or CodeFormer at moderate strength, and keep blend settings subtle. Over-restoration produces a plastic look that reads as fake. #### AI Image Inference Speed Benchmarks URL: https://geratools.com/inference-speed-benchmarks Reference table of inference speed benchmarks (images per minute) for SD 1.5, SDXL, and Flux.1 across common GPUs (RTX 3060, 3090, 4090, A100) and resolutions. Pick a model, GPU, and resolution to estimate throughput. How to use: 1. Pick your model: Choose SD 1.5, SDXL, or Flux.1 — heavier models produce fewer images per minute on the same GPU. 2. Select GPU and resolution: Pick the GPU you run on (or rent) and the output resolution. Larger resolutions roughly square the per-image cost. 3. Read the throughput estimate: See estimated images per minute and seconds per image, plus how it scales with your chosen step count. FAQ: Q: Where do these benchmark numbers come from? A: They are representative figures aggregated from community benchmarks at 25–30 steps with the Euler/DPM++ samplers. Your real numbers vary with sampler, VRAM, drivers, and whether xFormers or torch.compile is enabled. Q: Why is SDXL so much slower than SD 1.5? A: SDXL has a larger UNet and runs at a native 1024px versus SD 1.5's 512px, so each step processes roughly four times the pixels and a bigger model, cutting throughput several-fold. Q: Does step count change the speed linearly? A: Mostly yes — generation time is roughly proportional to step count, since each step is one UNet pass. Halving steps from 30 to 15 nearly halves the time, at some cost to detail. Q: Will a cloud A100 always beat my local 4090? A: Not for single images. A 4090 often matches or beats an A100 on one SD image because of higher clocks; the A100's advantage is large VRAM and batch throughput for many concurrent jobs. #### IP-Adapter Style Reference Guide URL: https://geratools.com/ip-adapter-guide Guide to IP-Adapter models for Stable Diffusion image-prompt conditioning — choosing between Base, Plus, Plus-Face, and Light variants, picking a weight for style versus content transfer, and combining IP-Adapter with ControlNet. How to use: 1. Choose your transfer goal: Decide whether you want to transfer overall style, a face, or full content. The tool recommends the right IP-Adapter model variant. 2. Set the weight: Pick a strength. Lower weights nudge the result toward the reference; higher weights dominate the generation. The tool suggests a starting range. 3. Apply the recommended settings: Load the recommended model and weight in your SD interface, optionally pair with ControlNet for pose or composition, and generate. FAQ: Q: What does IP-Adapter actually do? A: IP-Adapter conditions a Stable Diffusion generation on a reference image rather than only text. It encodes the reference and injects those features so the output borrows the reference's style, subject, or facial identity depending on the model variant and weight. Q: Which IP-Adapter model should I use? A: Use the Base or Plus model for general style and content, Plus-Face for transferring a specific face, and the Light model when you want a gentle stylistic nudge without overpowering your prompt. Plus variants capture more detail than the base. Q: What weight should I set? A: Around 0.4 to 0.6 transfers style while leaving room for your text prompt. 0.7 to 1.0 makes the reference dominate, useful for faces or strong content transfer. Below 0.4 is a subtle hint. Always tune to your specific images. Q: Can I use IP-Adapter with ControlNet? A: Yes, and it is a common combination. IP-Adapter handles style or identity from a reference image while ControlNet locks pose, depth, or composition from a separate control image. Lower the IP-Adapter weight slightly when stacking so the two don't fight. #### LLM Temperature & Parameter Guide URL: https://geratools.com/llm-temperature-guide Interactive reference that recommends temperature, top-p, max-tokens, and other sampling parameters per task type — creative writing, coding, summarisation, Q&A, classification — with reasoning and examples. Runs in your browser. How to use: 1. Pick your task type: Choose the kind of output you want — creative, factual Q&A, code, summarisation, classification, or extraction. 2. Set how deterministic you need it: Slide between "consistent every time" and "surprising and varied" to fine-tune the recommendation. 3. Apply the suggested parameters: Copy the recommended temperature, top-p, and max-tokens into your API call or playground and test on real inputs. FAQ: Q: What does temperature actually do? A: Temperature scales the model's output probabilities before sampling. Low values (near 0) make the model pick the most likely token almost every time — predictable and repetitive. High values (toward 1.5–2) flatten the distribution so less likely tokens get picked, giving variety and creativity at the cost of coherence. Q: Should I change temperature or top-p? A: Change one, not both. Temperature reshapes the whole distribution; top-p (nucleus sampling) keeps only the smallest set of tokens whose probabilities sum to p, then samples among those. Most teams pick a temperature and leave top-p at 1.0, or vice versa. Q: Why is temperature 0 recommended for code and extraction? A: For code, structured output, and data extraction you want the single most likely, correct continuation every time — not creative variety. Near-zero temperature maximises determinism and reproducibility, which matters for tests and pipelines. Q: Does a higher max-tokens cost more? A: Max-tokens only caps how long the response can be; you pay for tokens actually generated. Setting it generously is fine, but a tight cap protects you from runaway responses and surprise bills on completion-heavy tasks. #### OpenPose ControlNet Guide URL: https://geratools.com/openpose-guide Guide to using OpenPose with ControlNet. Covers the pose keypoint format, full body versus hands-and-face versus hands-only models, and recommended control-strength settings per use case for reliable human poses. How to use: 1. Choose the OpenPose model: Pick body-only, body plus hands and face, or hands-only depending on how much of the figure you need to control. 2. Generate the pose map: Run the OpenPose preprocessor on a reference image, or build a pose with an editor. The map is a stick-figure of keypoints the model follows. 3. Set control strength: Higher strength locks the pose tightly; lower strength lets the model reinterpret it. Tune by use case before generating. FAQ: Q: What does OpenPose ControlNet control? A: It controls the pose and position of human figures by extracting a skeleton of keypoints (joints) from a reference and forcing the generated person to match it. It controls posture, not appearance — clothing, style, and background still come from your prompt. Q: Which OpenPose model variant should I use? A: Use body-only for simple full-figure poses. Use body plus hands and face when expressions or precise finger positions matter — though hand keypoints are error-prone. Use hands-only when you just need to fix gestures on an otherwise good generation. Q: What control strength works best? A: A strength around 0.8 to 1.0 reproduces the pose faithfully and suits product or reference work. Drop to 0.5 to 0.7 when you want the model freedom to adjust the pose naturally to the prompt. Below 0.4 the pose becomes a loose suggestion the model may ignore. Q: Why do hands come out wrong even with OpenPose? A: Hand keypoint detection is far less reliable than body detection, and diffusion models already struggle with hands. The hands-and-face model helps but does not guarantee correct fingers. Often the best workflow is to fix the body pose with OpenPose and clean up hands separately with inpainting. #### PhotoMaker & InstantID Guide URL: https://geratools.com/photomaker-guide Guide to PhotoMaker and InstantID settings for consistent face generation. Tune reference image count, style strength and identity-preservation vs style balance to get faithful, repeatable AI portraits. How to use: 1. Pick your tool: Choose PhotoMaker for stacked multi-image identity embeddings or InstantID for single-image, ControlNet-style identity locking. Each behaves differently with reference count and strength. 2. Set identity preservation: Slide identity preservation toward high for a faithful likeness or lower it to let the model restyle the face. The tool maps your choice to the right strength values for the selected tool. 3. Apply the recommended config: Copy the suggested reference-image count, style strength and identity scale into your Automatic1111, ComfyUI or diffusers pipeline and generate. FAQ: Q: What is the difference between PhotoMaker and InstantID? A: PhotoMaker stacks several reference images into a single identity embedding, so it benefits from 3-4 varied photos. InstantID locks identity from one image using a face encoder plus a ControlNet-style adapter, so it works well from a single clear portrait. Q: How many reference images should I use for PhotoMaker? A: Three to four images of the same person from slightly different angles and lighting give the strongest, most flexible identity. One image works but tends to overfit to that exact pose and expression. Q: Why does my generated face look stiff or pasted on? A: Identity strength is too high. Lower the identity scale or PhotoMaker style strength so the model can blend the face into the scene lighting and pose instead of stamping the reference directly. Q: Can I combine both tools? A: Yes. A common ComfyUI pattern is InstantID for hard identity locking plus a PhotoMaker pass or IP-Adapter for style and detail. Keep total identity influence moderate so the two do not fight each other. #### SD Sampler Selector Guide URL: https://geratools.com/sd-sampler-guide Free Stable Diffusion sampler guide. Tell it whether you want speed, quality or consistency and it recommends a sampler (Euler a, DPM++ 2M Karras, DDIM and more) with a comparison table and step ranges — all in your browser. How to use: 1. Set your priority: Choose whether you care most about speed, final quality or reproducibility between runs. 2. Read the recommendation: The guide highlights the best-matching sampler and explains why, with a typical step range to start from. 3. Compare the full table: Scan the comparison table to see speed, quality, coherence and convergence for every popular sampler before you commit. FAQ: Q: What is the difference between ancestral and non-ancestral samplers? A: Ancestral samplers (names ending in 'a', like Euler a) inject noise at each step, so the image keeps changing and never fully converges. Non-ancestral samplers (Euler, DPM++ 2M, DDIM) converge to a stable result as steps increase, which is better for reproducibility and upscaling. Q: What is the safest all-round sampler? A: DPM++ 2M Karras is the common default — it gives sharp, coherent results in 20–30 steps and converges cleanly, which makes it reliable for both first passes and hires fix. Q: Why does the same seed look different on another sampler? A: Each sampler integrates the denoising path differently, so the same seed and prompt produce a different image per sampler. Lock the sampler along with the seed when you need reproducibility. Q: Is anything sent to a server? A: No. This is a static reference that runs in your browser. Nothing is uploaded, generated or logged. #### AI Video Upscaling Workflow Guide URL: https://geratools.com/video-upscaling-workflow-guide Step-by-step workflow for upscaling AI-generated video using Topaz Video AI, Real-ESRGAN and FFmpeg. Get a recommended scale factor, denoising and interpolation plan, plus an output codec based on your source and target resolution. How to use: 1. Set source and target: Enter your source resolution (often 512p or 720p from a video model) and your target, such as 1080p or 4K. The tool computes the scale factor. 2. Describe the motion: Pick the motion level. High-motion clips benefit from frame interpolation and gentler denoising to avoid smearing. 3. Follow the generated workflow: Copy the ordered steps and FFmpeg command for denoise, upscale, interpolation and final encode. FAQ: Q: Should I upscale before or after frame interpolation? A: Upscale first, then interpolate. Interpolation tools estimate motion between frames more accurately at higher resolution, and doing it last means the new in-between frames are already sharp. Doing it the other way can amplify interpolation artifacts. Q: Why denoise AI video before upscaling? A: AI-generated video often has subtle flicker and compression noise. Upscalers happily sharpen that noise into hard artifacts. A light denoise pass first gives the upscaler a cleaner signal and a much better result. Q: What scale factor is realistic? A: A 2x to 4x scale is the safe range for AI upscalers. Going beyond 4x in a single pass invents too much detail and looks plastic. For very large jumps, run two moderate passes rather than one extreme one. Q: Which output codec should I use? A: For delivery, H.264 (libx264) at CRF 18 is universally compatible; H.265 (libx265) halves the file size at the cost of slower encoding. For further editing, use a near-lossless intermediate like ProRes or DNxHR instead of a delivery codec. ### More AI Tools #### Chatbot Conversation Flow Designer URL: https://geratools.com/ai-chatbot-conversation-designer Free chatbot conversation flow designer. Enter your bot's purpose, user intents and escalation triggers to build a dialogue tree with greeting, intent, fallback and escalation nodes — each with a ready-to-use AI prompt. Runs in your browser. How to use: 1. Define your bot's purpose: State what the chatbot is for in one line so every node prompt stays anchored to the same job. 2. List user intents and escalation triggers: Add the things users will ask for and the conditions that should hand off to a human, so the flow covers happy paths and edge cases. 3. Copy the node prompts: Each node — greeting, intents, fallback, escalation — comes with a prompt. Paste them into your AI tool to write each response. FAQ: Q: What nodes does it generate? A: It builds a greeting node, one node per user intent, a fallback node for unrecognised input, and an escalation node for handing off to a human. Together these cover the core structure of any task-oriented bot. Q: Does it build a working chatbot? A: No — it designs the conversation flow and writes a prompt for each node's response. You take those prompts into your AI tool or bot platform to generate and wire up the actual replies. Q: How many intents should I add? A: Start with your three to six most common user requests. Covering the top intents resolves the majority of conversations; rarer ones can fall through to the fallback and escalation paths. Q: Is my flow data sent anywhere? A: No. The designer runs locally in your browser. Your bot purpose, intents and escalation triggers are never uploaded or stored. #### AI Environmental Impact Estimator URL: https://geratools.com/ai-environmental-impact-estimator Enter your AI usage pattern — provider, model tier, and approximate monthly query volume — and get an estimated energy use and carbon footprint for sustainability reporting, based on published per-query energy figures and grid carbon-intensity data. How to use: 1. Pick your model tier: Select whether you mainly use a small, mid, or large model, and add image generation volume if relevant. 2. Enter monthly query volume: Estimate how many text queries and images you run per month across your team or product. 3. Read the estimate: The tool shows estimated monthly energy use in kWh and CO2-equivalent emissions, with relatable comparisons for your report. FAQ: Q: How accurate is this estimate? A: It is an order-of-magnitude estimate, not a precise measurement. Per-query energy varies widely with prompt length, output length, model size, and data-center efficiency, and most providers do not publish exact figures. Use it for directional sustainability reporting, not as an audited number. Q: Where do the per-query energy figures come from? A: They are drawn from published research and provider disclosures on inference energy use, which generally place a typical short text query in the range of a fraction of a watt-hour for small models up to a few watt-hours for large models, with image generation higher. The tool uses representative midpoints. Q: What carbon intensity does it use? A: It converts energy to emissions using a configurable grid carbon-intensity figure (grams of CO2 per kWh). You can set it to your data-center region's value; the default reflects a typical mixed grid. Cloud regions on low-carbon grids will be substantially lower. Q: Does this include training, or just inference? A: Only inference — the energy of running queries. Training a large model is a large one-time cost amortized across all users, and is generally reported separately by the model provider rather than by you as an API consumer. Q: Can I use this for an ESG or CSRD report? A: It is a reasonable starting estimate and a transparent methodology, but formal ESG/CSRD reporting should use provider-supplied figures where available and be reviewed by your sustainability team. Document your assumptions alongside the number. #### AI-Generated Image Metadata Checker URL: https://geratools.com/ai-generated-image-metadata Upload an image and inspect its metadata for AI generation indicators — C2PA content credentials, DALL-E/Midjourney/Stable Diffusion markers, Adobe Content Authenticity tags, and suspicious metadata absences. How to use: 1. Upload an image: Choose a JPEG or PNG file. The image is read entirely in your browser and never uploaded to a server. 2. Read the indicators: The tool scans the file's bytes for C2PA credentials, generator markers, and software tags, then reports what it found. 3. Interpret the verdict: Use the indicators and the absence-of-metadata signal as evidence, not proof — combine with visual judgment and other tools. FAQ: Q: Can this prove an image is AI-generated? A: No. It detects metadata indicators that are commonly present in AI images, such as C2PA credentials or generator tags. Metadata can be stripped or faked, so treat findings as evidence, not definitive proof. Q: What is C2PA? A: C2PA (Coalition for Content Provenance and Authenticity) is an open standard for cryptographically-signed content credentials. Many AI tools and cameras embed C2PA manifests describing how an image was made. The checker flags when these are present. Q: Why does stripped metadata matter? A: Sharing platforms and editors often strip metadata, so absence alone proves nothing. But an image with no metadata at all, when one would expect camera EXIF, can be a mild signal worth noting alongside other evidence. Q: Is my image uploaded anywhere? A: No. The file is read with the browser's FileReader and scanned locally in JavaScript. It never leaves your device, so you can safely inspect private images. Q: Which formats are supported? A: It works best on JPEG and PNG, scanning for EXIF/IPTC/XMP text segments and C2PA markers. Other formats may show fewer results because their metadata is structured differently. #### AI Image Metadata Viewer URL: https://geratools.com/ai-image-metadata-viewer Client-side viewer that reads PNG text chunks and JPEG metadata from AI-generated images to surface embedded generation parameters — prompt, negative prompt, model, seed, steps, CFG scale, and sampler — without uploading the file anywhere. How to use: 1. Select an image: Choose a PNG or JPEG that was produced by an AI image tool. The file is read in your browser and never uploaded. 2. View the parsed parameters: If generation metadata is embedded, the tool extracts and labels the prompt, negative prompt, model, seed, steps, CFG, and sampler. 3. Copy what you need: Copy the full raw parameter string or reuse the parsed prompt and settings to reproduce or remix the image. FAQ: Q: Where does the metadata come from? A: Stable Diffusion tools like AUTOMATIC1111 write generation parameters into a PNG tEXt chunk (usually keyed "parameters"). Other tools use EXIF UserComment or ImageDescription fields. This viewer reads those embedded strings directly in your browser. Q: Why does my Midjourney image show nothing? A: Images downloaded from social platforms or Discord are often re-encoded, which strips metadata. Midjourney also does not embed full parameters the way SD does. If the chunk was removed, there is nothing to recover. Q: Is my image uploaded anywhere? A: No. The file is read locally using the browser's FileReader. Nothing is sent to a server, so it is safe to inspect private images. Q: What formats are supported? A: PNG tEXt and iTXt chunks are parsed directly, and JPEG EXIF UserComment and ImageDescription fields are read. WebP and heavily compressed exports usually have their metadata stripped. #### AI Model Deprecation Tracker URL: https://geratools.com/ai-model-deprecation-tracker Reference tracker of announced and scheduled model retirements across OpenAI, Anthropic, Google, and Cohere, with days-remaining countdowns, recommended replacements, and migration notes. Filter to the models you actually run. How to use: 1. Filter to your models: Tick the providers you use or paste your model IDs to filter the list down to what is relevant to your stack. 2. Read the countdown: Each entry shows the announced retirement date, days remaining, and the status — active, deprecated, or retired. 3. Plan your migration: Use the recommended replacement and migration note for each model to schedule the swap before the date arrives. FAQ: Q: Are these dates official? A: They reflect publicly announced or scheduled retirement dates as of the page's update date. Providers can change schedules, so always confirm against the provider's own deprecation page before relying on a date for a production migration. Q: How current is this list? A: The list carries an update date in the page metadata. Model lifecycles move quickly, so treat it as a planning aid and verify the most time-sensitive dates directly with the provider. Q: Why do models get deprecated? A: Providers retire older snapshots to consolidate on newer, cheaper, or more capable models, to reduce serving costs, and to address safety or licensing changes. Pinned snapshot IDs are the most likely to be retired. Q: What happens if I do not migrate in time? A: Requests to a retired model typically start returning errors or get silently routed to a successor, which can change behaviour and break output parsing. Migrate and re-test before the date, not after. Q: How do I avoid surprise breakages? A: Avoid hardcoding pinned snapshot IDs where you can, subscribe to your providers' deprecation notices, and keep a model inventory so you know exactly which calls to update when a date lands. #### AI Model Selection Wizard URL: https://geratools.com/ai-model-selection-wizard A guided wizard covering task type, accuracy needs, latency budget, privacy level, monthly volume, and cost ceiling that recommends an LLM tier with clear pros, cons, and alternatives so you pick the right model without guesswork. How to use: 1. Answer the questions: Pick your task type, accuracy requirement, latency budget, privacy level, monthly volume, and cost ceiling using the dropdowns. 2. Read the recommendation: The wizard scores model tiers against your answers and surfaces the best fit with a plain-language reason. 3. Review pros, cons, and alternatives: Check the trade-offs and the runner-up tier before committing, then validate the choice on your own eval set. FAQ: Q: Does it recommend a specific model name? A: It recommends a tier — frontier, mid-tier, small/mini, or self-hosted open weights — and names current representative models in each. Tiers are more durable than exact model names, which change every few months, so the guidance stays useful. Q: How does privacy affect the recommendation? A: A strict privacy or data-residency requirement pushes the wizard toward self-hosted open-weight models or providers with zero-retention enterprise terms, even if a hosted frontier model would otherwise win on accuracy. Q: Why does latency matter so much? A: Frontier reasoning models are accurate but slow and expensive per call. If you need sub-second responses for an interactive product, the wizard favors smaller, faster models and suggests reserving frontier calls for hard sub-tasks. Q: Is the recommendation a guarantee? A: No. It is a strong starting point based on common trade-offs. Always confirm with your own evaluation set, because real performance depends on your exact prompts, data, and quality bar. Q: What if cost and accuracy conflict? A: The wizard weighs your stated ceiling against your accuracy requirement and explains the tension explicitly, often suggesting a routing strategy — a cheap model for easy cases, an escalation to a frontier model for hard ones. #### AI Decision Newspaper Test URL: https://geratools.com/ai-newspaper-test Describe your AI system's decision-making capability and run it through a structured newspaper test — evaluating both over-harm risk (a harmful output making the front page) and over-caution risk (an unhelpful refusal making the front page) to surface PR and safety exposure. How to use: 1. Describe the decision: Explain what your AI system decides or outputs and the context it operates in. Be specific about who is affected. 2. Rate the risk factors: Score the factors that drive both a harmful-output headline and an unhelpful-refusal headline. The test scores both directions, not just harm. 3. Read both headlines: See a plausible over-harm headline and a plausible over-caution headline, plus the factors driving each, so you can mitigate before launch. FAQ: Q: What is the newspaper test? A: It is a classic ethics heuristic — would you be comfortable if your decision were reported on the front page of a newspaper? Applied to AI, it asks whether a single output, good or bad, could become a damaging story. Q: Why test for over-caution as well as over-harm? A: AI systems fail in both directions. An over-harmful system makes headlines for a toxic or dangerous output; an over-cautious one makes headlines for refusing a reasonable, important request — like declining medical or safety information. Optimising only against harm creates the opposite scandal. Q: Is the headline a real prediction? A: No. The generated headlines are illustrative prompts to make the risk concrete and memorable. Use them to imagine the worst-case story and design mitigations, not as a forecast of actual press coverage. Q: Does this tool store what I describe? A: No. The entire test runs in your browser. Nothing you type about your system is uploaded or stored. #### AI Recruitment Tool Fairness Checker URL: https://geratools.com/ai-recruitment-fairness-checker Evaluate an AI recruitment tool against a structured fairness checklist — covering training data demographics, validation study design, adverse impact testing, explainability for rejected candidates, right to appeal, and bias monitoring — before you buy or deploy. How to use: 1. Describe the tool and stage: Note the vendor tool and whether it is used for screening, interview scoring, or final selection — later stages carry higher fairness risk. 2. Answer the fairness questions: Work through questions on training data, validation, adverse impact testing, explainability, and appeals. Answer honestly based on vendor documentation. 3. Read your risk rating: Get a weighted fairness risk rating and a list of the unanswered or failing questions to raise with the vendor before procurement. FAQ: Q: What is adverse impact and the four-fifths rule? A: Adverse impact occurs when a selection process passes one protected group at a substantially lower rate than another. The common four-fifths (80%) rule flags a problem when a group's selection rate is below 80% of the highest group's rate — a widely used screening test for disparate impact. Q: Why does the use stage matter? A: A tool that ranks thousands of CVs has broad, automated reach, while a tool that suggests interview questions has a human firmly in the loop. The further a tool sits from final selection with human review, the lower its standalone fairness risk. Q: Should an AI tool be able to explain a rejection? A: Yes, where it materially affects candidates. Many jurisdictions are moving toward a right to a meaningful explanation of automated decisions, and explainability is also your best defence if a hiring decision is challenged. Q: Does this tool save my answers? A: No. The checker evaluates everything in your browser. Nothing you enter about the vendor or your answers is uploaded or stored. #### AI Social Engineering Awareness Guide URL: https://geratools.com/ai-social-engineering-awareness Interactive guide to AI-enhanced social engineering — voice-cloning scams, AI-generated spear phishing, and deepfake impersonation — with concrete detection tips and organizational defense protocols you can apply right away. How to use: 1. Pick an attack type: Choose the AI-enhanced attack you want to understand — phishing, voice cloning, or deepfake impersonation. 2. Read the signs and defenses: Review the detection signals and the recommended response for that attack pattern. 3. Apply the protocol: Adopt the call-back verification and approval steps as standing procedure so they work under pressure. FAQ: Q: What makes AI-enhanced phishing harder to spot? A: Generative AI removes the classic tells. Messages have correct grammar, match a target's tone and context, and can be personalised at scale using scraped data. The old advice of looking for typos no longer works, so detection must rest on process rather than spotting mistakes. Q: How do AI voice-cloning (vishing) scams work? A: An attacker captures a few seconds of someone's voice — from a voicemail, video, or call — and clones it to leave urgent requests, often pretending to be an executive or family member asking for a transfer or credentials. The voice sounds right, which is exactly why an out-of-band call-back is the defense. Q: What is the single most effective defense? A: Out-of-band verification. Any unusual request involving money, credentials, or sensitive data is confirmed through a separate, known channel — calling back a number you already have, not one supplied in the message. This neutralises a convincing voice, face, or email because the attacker does not control the second channel. Q: Are deepfake video calls a real threat? A: Yes. Real-time deepfakes have been used to impersonate executives on video calls and authorise large transfers. Defenses include code words, asking the person to perform an unexpected action live, and never approving high-value actions on the strength of a video call alone. Q: Does this replace formal security training? A: No. It is an awareness aid. Combine it with your organisation's formal training, technical controls like email authentication and MFA, and clear approval workflows for financial and access requests. #### AI System Bill of Materials Generator URL: https://geratools.com/ai-supply-chain-sbom Build an AI System Bill of Materials (AI-SBOM) documenting models, datasets, APIs, libraries, and third-party components in your AI stack — following NIST AI RMF guidance on supply chain transparency. How to use: 1. Add each component: List every model, dataset, API, and library in your AI stack with its type, supplier, version, and license. 2. Review completeness: The tool flags missing fields and highlights components with unknown licenses or suppliers that weaken supply-chain transparency. 3. Export the AI-SBOM: Copy the generated Markdown or JSON bill of materials into your documentation, audit pack, or governance system. FAQ: Q: What is an AI-SBOM? A: An AI System Bill of Materials is a structured inventory of every component that goes into an AI system — models, datasets, APIs, libraries, and services — with provenance and licensing. It extends the software SBOM concept to AI supply chains as encouraged by NIST AI RMF and emerging regulation. Q: Why do I need one? A: You cannot manage risk in components you have not catalogued. An AI-SBOM is the basis for licence compliance, vulnerability response, vendor-exit planning, and demonstrating governance to auditors and regulators. Q: What fields matter most? A: Type, supplier, version, and license are the core. Version lets you respond to vulnerabilities and deprecations; supplier and license drive compliance and exit decisions; type lets you reason about the whole stack at once. Q: Is the data stored anywhere? A: No. The inventory is built and exported entirely in your browser. Nothing is uploaded, which matters because the SBOM itself can be sensitive. Q: How often should I update it? A: Treat it as living documentation — update whenever you add, upgrade, or remove a model, dataset, or dependency. Stale SBOMs give false assurance, so tie updates to your release process. #### AI Terms of Service Decoder URL: https://geratools.com/ai-terms-decoder Select a major AI provider and get a plain-English breakdown of the most privacy-relevant clauses in their terms — data training opt-outs, retention periods, third-party sharing, and the difference between consumer and enterprise plans. How to use: 1. Pick a provider: Choose the AI service you use, such as OpenAI ChatGPT, Anthropic Claude, or Google Gemini. 2. Read the plain-English clauses: See how each provider handles training on your data, retention, sharing, and enterprise differences in clear language. 3. Verify against the live policy: Use the linked questions to confirm details on the provider's current policy page before relying on them. FAQ: Q: Is this legal advice? A: No. This is an educational summary to help you understand common privacy clauses in AI terms of service. Policies change frequently, so always confirm specifics in the provider's current official documents before making decisions. Q: Do AI providers train on my conversations? A: It depends on the provider and plan. Many consumer plans use your inputs to improve models by default unless you opt out, while business, enterprise, and API tiers usually exclude your data from training by default. The decoder summarizes the typical posture for each provider. Q: How long do providers keep my data? A: Retention varies. Some keep conversations for around 30 days for abuse monitoring even when training is disabled, and longer if needed for legal or safety reasons. Enterprise agreements often allow custom or zero retention. Q: What is the difference between consumer and enterprise plans? A: Consumer plans typically have looser defaults — training opt-in, standard retention — while enterprise and API plans usually offer training exclusion, configurable retention, data-processing agreements, and stronger confidentiality commitments. Q: Is the information always up to date? A: The summaries reflect common provider posture as of the update date, but AI terms change often. Treat this as a starting map and verify any clause that matters to you on the provider's live policy page. #### AI Use Case Library URL: https://geratools.com/ai-use-case-library A filterable library of proven and emerging AI use cases across many industries and business functions, each with a short description, suggested tool category, and a proven-or-emerging maturity tag to help you prioritise. How to use: 1. Filter by industry: Choose your sector to narrow the list to use cases that matter for your business. 2. Filter by function and maturity: Pick a business function and whether you want proven or emerging applications. 3. Review and shortlist: Read each use case, its suggested tool category, and pick the ones worth a pilot. FAQ: Q: Are these real use cases? A: Yes. The library lists applications of AI that are already in production across these industries, plus a smaller set of emerging ones that are credible but less established. Each is tagged so you can tell them apart. Q: What does the maturity tag mean? A: "Proven" means the use case is widely deployed with established tools and clear ROI patterns. "Emerging" means it is being adopted but is newer, riskier, or dependent on fast-moving capabilities — pilot before scaling. Q: Does it recommend specific products? A: It suggests a tool category (for example "RAG chatbot" or "document extraction") rather than naming vendors, so the guidance stays current. Use it as a starting point for your own tool selection. Q: How should I prioritise? A: Start with proven use cases in functions where you have clean data and a measurable cost. Use the companion ROI business case builder to quantify the top two or three before committing budget. Q: Is anything sent to a server? A: No. The library and all filtering run entirely in your browser. Nothing you click is logged or transmitted. #### Anthropic Usage Stats Parser URL: https://geratools.com/anthropic-usage-parser Extracts input_tokens, output_tokens, cache_creation_input_tokens, and cache_read_input_tokens from an Anthropic Messages API response and shows a per-model cost estimate. Runs entirely in your browser, no API key required. How to use: 1. Paste the response JSON: Copy the full JSON returned by an Anthropic Messages call and paste it in. The parser reads the usage object automatically. 2. Pick the Claude model: Select the model you called so the cost estimate uses the correct per-million-token prices for input, output, cache write, and cache read. 3. Read the breakdown: See input, output, cache-creation, and cache-read token counts plus an estimated USD cost that accounts for the different cache billing rates. FAQ: Q: Do I need an API key? A: No. This tool parses a response you already received. Everything runs locally in your browser and nothing is uploaded. Q: What are cache_creation and cache_read tokens? A: cache_creation_input_tokens are the tokens written into the prompt cache (billed at a premium), while cache_read_input_tokens are read back from the cache on later calls (billed at a deep discount). They make repeated long prompts much cheaper. Q: How is the cost estimated? A: It applies published per-million-token list prices for the selected model. Cache writes are billed at 1.25x the input rate and cache reads at 0.1x, which the estimate reflects. Q: Where is the usage object in an Anthropic response? A: At the top level of a Messages API response there is a usage object containing input_tokens, output_tokens, and the two cache fields. The parser reads it directly. #### API Key Format Validator URL: https://geratools.com/api-key-format-validator Checks an LLM API key's prefix, length, and character set against the known formats for OpenAI, Anthropic, Cohere, Mistral, Groq, and Google. Format-only — there are no network calls, so your key is never sent anywhere. How to use: 1. Paste the key: Drop the API key into the field. It is checked locally and never transmitted. 2. Read the detected provider: The tool matches the prefix and structure against known patterns and tells you which provider the key looks like. 3. Check the validity notes: See whether the prefix, length, and character set all match, plus any warnings — for example a restricted versus standard key. FAQ: Q: Does this verify the key actually works? A: No. It only checks that the format matches a known provider pattern — prefix, length, and allowed characters. A correctly formatted key can still be revoked or invalid; only a real API call confirms it works, which this tool deliberately does not do. Q: Is my key sent anywhere? A: No. There are zero network requests. All checks run in your browser against built-in regular expressions, so it is safe to paste a live key. Q: Which providers are recognized? A: OpenAI (including project and restricted keys), Anthropic, Cohere, Mistral, Groq, and Google AI Studio. Unknown formats are reported as unrecognized rather than guessed. Q: Why does my OpenAI project key look different? A: OpenAI issues several key shapes — classic "sk-" keys, project keys prefixed "sk-proj-", and restricted "sk-svcacct-" keys. The validator recognizes each and labels which variant you pasted. #### API Key & Secret Scrubber URL: https://geratools.com/api-key-scrubber Scans pasted text and code for API keys, tokens, and secrets matching 40+ common patterns — OpenAI sk-, AWS AKIA, GitHub ghp_, Stripe sk_live, JWTs, private keys and more — and replaces each with a safe placeholder before you share with an AI or paste into an issue. How to use: 1. Paste your code or logs: Drop the snippet, config file, or log output you want to share into the input box. 2. Review detected secrets: The tool lists each match with the provider it matched and the rule that caught it, then replaces it with a typed placeholder. 3. Copy the scrubbed text: Copy the cleaned output and share it safely. The original stays on your device. FAQ: Q: Which secret formats does it detect? A: It matches 40+ patterns including OpenAI (sk-, sk-proj-), Anthropic (sk-ant-), AWS access keys (AKIA), GitHub tokens (ghp_, gho_, ghs_), Stripe (sk_live, rk_live, pk_live), Google API keys (AIza), Slack (xoxb/xoxp), JWTs, generic bearer tokens, and PEM private key blocks. Q: Will it produce false positives? A: Some generic rules — like long high-entropy strings — can flag non-secrets such as hashes or IDs. The detection list shows exactly what matched so you can confirm before sharing. Specific provider rules rarely misfire. Q: Does it modify my secret or just hide it? A: It replaces the secret with a labelled placeholder such as [OPENAI_KEY_1]. The real value is never transmitted, and identical values reuse the same token so the structure of your snippet stays intact. Q: Is anything sent to a server? A: No. All scanning happens in your browser with regular expressions. Nothing is uploaded, logged, or stored — safe to use even on live production secrets. Q: If a key was already exposed, is scrubbing enough? A: No. If a real secret leaked anywhere it should be considered compromised and rotated immediately. Scrubbing only prevents future exposure of values that have not yet left your machine. #### Text Chunking Previewer URL: https://geratools.com/chunking-previewer Free RAG chunking previewer. Paste any document, set chunk size, overlap and split strategy (character, sentence, paragraph), and see a color-coded preview of every chunk and its overlap region before you embed and index. How to use: 1. Paste your document: Drop in the raw text you plan to embed and index. The previewer runs entirely in your browser, so even long internal documents stay private. 2. Set chunk size, overlap and strategy: Choose a target chunk size and overlap (in characters), then pick a split strategy — fixed character windows, sentence boundaries, or paragraph boundaries. 3. Read the color-coded preview: Each chunk is shown in a numbered card with its length, and the overlapping tail shared with the next chunk is highlighted so you can tune for retrieval quality. FAQ: Q: What is chunk overlap and why does it matter? A: Overlap repeats the last N characters of one chunk at the start of the next so a fact that straddles a boundary still appears whole in at least one chunk. Typical overlap is 10–20% of chunk size; too little loses context, too much wastes embedding cost. Q: How big should my chunks be? A: It depends on your embedding model and retrieval task. Many RAG pipelines use 500–1000 characters (roughly 100–250 tokens) per chunk. Smaller chunks give more precise retrieval; larger chunks preserve more surrounding context. Q: Why split on sentences or paragraphs instead of fixed size? A: Fixed-character splitting can cut a sentence in half, which hurts embedding quality. Sentence and paragraph strategies keep semantic units intact while still respecting your target size, producing cleaner, more retrievable chunks. Q: Is my document sent to a server? A: No. All chunking happens locally in your browser using plain JavaScript. Nothing you paste is uploaded, stored or logged. #### AI-Generated Image Commercial License Checker URL: https://geratools.com/commercial-license-checker Decision-tree tool for checking commercial licensing of AI-generated images. Covers DALL·E 3 (commercial allowed), Midjourney (subscriber dependent), Stable Diffusion (model license), and Adobe Firefly so you know whether you can sell or publish an image. How to use: 1. Pick the tool: Select the model or service that generated your image — licensing rules differ sharply between DALL·E, Midjourney, Stable Diffusion, and Firefly. 2. Set your plan and intended use: Choose your subscription tier where relevant and describe whether the use is internal, published, or sold. Some platforms only grant commercial rights to paying subscribers. 3. Read the verdict: The tool returns a plain-language verdict plus the key caveats — indemnification, model-license obligations, and copyright-registration limits — so you can decide with confidence. FAQ: Q: Can I sell images I made with DALL·E 3? A: Yes. OpenAI assigns you ownership of the images you create and permits commercial use under its terms. You are responsible for ensuring the content itself does not infringe trademarks or depict real people without consent. Q: Does Midjourney let me use images commercially? A: Paid subscribers generally own their images and may use them commercially. Free trial output and users at companies earning over one million USD per year on the Basic plan face restrictions, so the tier matters. Q: What about Stable Diffusion images? A: It depends on the specific model checkpoint's license. Many SD models use OpenRAIL-M, which permits commercial use with use-based restrictions. Always check the license of the exact model and any LoRAs you used. Q: Can AI images be copyrighted? A: In the US, purely AI-generated images cannot be registered for copyright because they lack human authorship. Significant human creative input (arrangement, editing, selection) can support a registration for those human-authored elements. #### Context Utilization Efficiency Score URL: https://geratools.com/context-utilization-efficiency Calculate what fraction of each request actually carries useful content versus padding, repetition, and formatting overhead — and what the wasted tokens cost you per month. Runs entirely in your browser. How to use: 1. Enter your average prompt size: Type the average input tokens per request and your model's context window so the tool can show how full the window is. 2. Estimate your useful content fraction: Give a rough percentage of each prompt that is genuinely useful, as opposed to boilerplate, repeated instructions, or formatting overhead. 3. Read your efficiency score and wasted cost: See your utilization percentage, an efficiency score, and the monthly dollar cost of the tokens that are not pulling their weight. FAQ: Q: What is context utilization? A: It is the fraction of your model's context window that a request actually uses. Sending 8,000-token prompts to a 200,000-token model is 4% utilization. Low utilization is not waste by itself — paying for a window you do not need is. Q: What is the useful content fraction? A: It is the share of each prompt that genuinely helps the model versus padding — repeated instructions, verbose formatting, stale conversation history, or duplicated context. The wasted share still costs full price, so trimming it directly cuts your bill. Q: How is the wasted monthly cost calculated? A: Wasted tokens equal prompt tokens times (1 minus useful fraction). Multiply by your input price per million and by monthly request volume to get the dollar cost of tokens that add no value. Q: Should I always aim for high window utilization? A: No. Filling a large window can hurt recall and slow responses. The goal is high useful-content fraction within a right-sized window, not cramming the window full. Q: Is anything sent to a server? A: No. The score is computed in your browser. Nothing you enter is uploaded or stored. #### Chain-of-Thought Trace Formatter URL: https://geratools.com/cot-trace-formatter Detects reasoning steps in LLM output — numbered, lettered, bulleted, or prose-style — and reformats them into a clean numbered trace with step IDs plus a separated final-answer section, making long chain-of-thought output skimmable. How to use: 1. Paste the reasoning output: Drop in the model's chain-of-thought text, however it is formatted. 2. Let it detect the steps: The tool recognizes numbered, lettered, bulleted, and prose step markers and splits them into discrete steps. 3. Read the clean trace: Steps are renumbered with IDs and the final answer is pulled into its own section, with a copy button for the whole trace. FAQ: Q: What step formats are detected? A: Numbered (1. / 1) / Step 1:), lettered (a. / A)), bulleted (- / * / •), and prose markers like First, Next, Then, Finally. When no explicit markers exist, it falls back to splitting on blank lines so you still get a readable trace. Q: How is the final answer separated? A: The tool looks for a trailing segment introduced by phrases like \"Final answer\", \"Answer:\", \"Therefore\", or \"In conclusion\" and lifts it into its own section below the numbered steps. If none is found, the last step is shown as the conclusion. Q: Will it lose any text? A: No. Every line of input lands in either a step or the final-answer section — nothing is dropped. The tool only reorganises and renumbers; it never paraphrases or summarises your reasoning. Q: Does it send my reasoning anywhere? A: No. All parsing runs locally in your browser. The chain-of-thought text never leaves the page, so sensitive reasoning stays private. #### CSV → JSONL Converter for LLM Training URL: https://geratools.com/csv-to-jsonl Map CSV columns to a prompt/completion pair or an OpenAI-style chat messages format, preview the generated JSON Lines, and download a ready-to-upload .jsonl file for LLM fine-tuning. Runs entirely in your browser. How to use: 1. Paste your CSV: Paste CSV text with a header row. The tool parses it, handling quoted fields and commas inside quotes. 2. Map columns: Choose the output format — chat messages or prompt/completion — and map your CSV columns to the system, user, and assistant (or prompt/completion) fields. 3. Preview and download: Review the generated JSON Lines, then download a .jsonl file ready to upload for fine-tuning. FAQ: Q: What output formats are supported? A: Two — the modern chat format with a messages array (optional system, plus user and assistant turns), and the classic prompt/completion pair. Pick the one your fine-tuning provider expects. Q: Does it handle quoted CSV fields? A: Yes. The parser respects double-quoted fields, escaped quotes ("") inside them, and commas or newlines within quotes, so messy exports convert cleanly. Q: What is JSONL and why fine-tuning uses it? A: JSONL (JSON Lines) puts one JSON object per line. Fine-tuning APIs stream the file line by line, so each line is one independent training example — exactly one conversation or prompt/completion pair. Q: Is my data uploaded anywhere? A: No. Parsing, conversion, and download all happen in your browser. Nothing is sent to a server or stored. #### AI Data Controller/Processor Classifier URL: https://geratools.com/data-controller-processor-classifier Answer questions about how you use an AI provider's API with your customers' data to determine whether you act as a data controller, processor, or joint controller under GDPR — with the contract and liability implications of each role. How to use: 1. Describe how you use the AI API: Answer a short set of questions about who decides the purpose, who chooses the data, and how the provider may reuse it. 2. Read your classified role: The tool maps your answers to controller, processor, or joint controller, with the reasoning behind it. 3. Act on the implications: Use the listed contract and liability consequences to put the right agreement (DPA, joint-controller arrangement) in place. FAQ: Q: What is the difference between a controller and a processor? A: A controller decides the purposes and means of processing personal data. A processor only acts on the controller's documented instructions. Your role determines your legal obligations and who is accountable to data subjects. Q: Can both my company and the AI provider be controllers? A: Yes. If the provider uses your customers' data for its own purposes — such as training its models — it becomes a controller for that purpose, and you may be joint controllers, each with direct GDPR obligations. Q: Why does the AI provider's data reuse matter so much? A: A provider that only processes inputs to return outputs on your instructions is usually a processor. The moment it reuses your data for its own benefit (model training, analytics), it determines its own purpose and stops being a pure processor. Q: Is this a definitive legal determination? A: No. Roles depend on the full factual context and contract terms. This tool gives a well-reasoned indication so you ask the right questions, but a data protection lawyer should confirm before you rely on it. Q: What should I do once I know my role? A: As a controller using a processor, sign a GDPR Article 28 data-processing agreement. If you are joint controllers, put a transparent arrangement in place defining responsibilities. Either way, document the analysis. #### ElevenLabs API Playground URL: https://geratools.com/elevenlabs-api-playground Browser-based ElevenLabs text-to-speech tester. Enter a voice ID, adjust stability, similarity boost, and style, type your text, then play and download the audio. Shows character usage before generation. Bring your own key — it is never stored. How to use: 1. Paste your ElevenLabs key: Enter your own ElevenLabs API key. It stays in your browser and is sent only in the direct request to ElevenLabs. 2. Set the voice and voice settings: Paste a voice ID from your ElevenLabs library and adjust stability, similarity boost, and style to control consistency and expressiveness. 3. Generate, play, and download: Generate to call the text-to-speech endpoint directly. The audio plays inline and can be downloaded as an MP3. FAQ: Q: Where do I find a voice ID? A: Open the voice in your ElevenLabs VoiceLab or the Voices page; the voice ID is in the URL and on the voice's details. Paste that 20-character ID here. A default Rachel ID is pre-filled as a starting point. Q: What do stability and similarity boost do? A: Stability controls how consistent the voice is — higher is steadier but flatter, lower is more expressive but variable. Similarity boost pushes the output toward the original voice's timbre. Style adds exaggeration on supported models. Q: How is usage charged? A: ElevenLabs bills credits per character of input text, with your plan setting the monthly quota. The playground shows the character count so you can gauge usage before generating; the exact credit conversion depends on your plan and model. Q: Is anything stored? A: No. The audio is held only in your browser as a temporary object URL and your API key is never persisted. The request goes directly from your browser to the ElevenLabs API. #### Frame Interpolation FPS Calculator URL: https://geratools.com/frame-interpolation-calculator Enter source FPS, target FPS, and duration to get the output frame count, interpolation factor, and estimated RIFE/DAIN processing time. Includes motion-blur and artifact advice. Runs entirely in your browser. How to use: 1. Enter source and target FPS: Type the frame rate of your generated clip (often 8–16fps) and the smooth target you want, such as 24, 30, or 60fps. 2. Set the duration: Enter the clip length in seconds so the tool can compute total source and output frames. 3. Read frames and processing estimate: See the interpolation factor, total output frames, and a rough processing-time estimate for RIFE or DAIN models. FAQ: Q: What is frame interpolation? A: It generates new in-between frames so choppy low-FPS video plays smoothly. RIFE and DAIN are neural models that predict motion between two real frames and synthesise the frames in between. Q: What interpolation factor should I use? A: The factor is target FPS ÷ source FPS. Whole-number factors (2×, 3×) interpolate cleanest. Non-integer ratios still work but the model must resample timing, which can introduce slight judder. Q: Will interpolation fix bad AI video? A: It smooths motion but can amplify existing artifacts — morphing, warping, or flicker get interpolated too. Fix the source clip first, then smooth it. Q: How long does interpolation take? A: Roughly proportional to the number of output frames and your GPU. The estimate here assumes a mid-range GPU at a few frames per second; faster hardware is quicker. #### Function Call Response Parser URL: https://geratools.com/function-call-response-parser Paste a raw OpenAI or Anthropic API response containing tool_calls or tool_use blocks and instantly extract each function name, its JSON arguments (pretty-printed), and call IDs. Runs fully in your browser. How to use: 1. Paste the response: Copy the full JSON response from your OpenAI or Anthropic API call and paste it into the box. The parser auto-detects the format. 2. Read the extracted calls: Each tool/function call is shown with its name, call ID, and arguments pretty-printed as formatted JSON, even when the API returned arguments as an escaped string. 3. Copy what you need: Use the copy button on any call's arguments to grab clean JSON for testing your handler or logging. FAQ: Q: Which response formats are supported? A: Both OpenAI (choices[].message.tool_calls with function.arguments as a JSON string) and Anthropic (content[] blocks of type tool_use with an input object). The parser detects which one you pasted. Q: Why are OpenAI arguments a string? A: OpenAI returns function arguments as a JSON-encoded string rather than a nested object. This parser decodes and re-formats them so you can read and validate the actual values. Q: What if my JSON is invalid? A: The tool shows a clear parse error pointing at the problem rather than failing silently, so you can fix the paste and try again. Q: Is anything sent to a server? A: No. All parsing happens in your browser. Nothing you paste is uploaded, stored, or logged. #### SD Hires.fix Resolution Calculator URL: https://geratools.com/hires-fix-calculator Enter a target output resolution and upscale factor and this calculator works out the correct base generation resolution to feed into Stable Diffusion hires.fix, with a rough VRAM estimate per model so you avoid out-of-memory errors. How to use: 1. Enter your target resolution: Type the final width and height you want the finished image to be, for example 2048×2048 for a print or 1920×1080 for a wallpaper. 2. Choose an upscale factor and model: Pick how much hires.fix should upscale (1.5×–2× is typical) and select SD 1.5 or SDXL so the base resolution lands in the model's sweet spot. 3. Read the base resolution and VRAM estimate: The tool divides the target by the upscale factor to give the base generation size and shows a rough VRAM requirement so you can tell if your GPU can handle it. FAQ: Q: What is hires.fix? A: Hires.fix is a two-pass Stable Diffusion workflow. The model first generates at a low base resolution it was trained on, then upscales and runs a second img2img pass to add detail. It produces sharper large images than generating at high resolution directly. Q: Why not just generate at the full target resolution? A: Models are trained around a native resolution (512px for SD 1.5, 1024px for SDXL). Generating far above that causes duplicated limbs, repeated patterns and warped anatomy. Hires.fix keeps the first pass at the native size to avoid this. Q: What base resolution should SD 1.5 use? A: SD 1.5 works best with a base around 512–768px on the long edge. The calculator divides your target by the upscale factor; if the result drifts far from that range, lower the factor or pick a different target. Q: How accurate is the VRAM estimate? A: It is a rough guide based on pixel count and model. Real usage depends on batch size, sampler, attention optimisations like xformers, and whether you use tiled VAE. Treat it as a sanity check, not a guarantee. #### IP Address Scrubber URL: https://geratools.com/ip-address-scrubber Paste server logs or network data and automatically detect and replace every IPv4 and IPv6 address with anonymized placeholders — preserving log structure for AI analysis without exposing user IP addresses, entirely in your browser. How to use: 1. Paste your logs: Drop server logs or network data into the box. Detection runs locally as you type, with no upload. 2. Choose consistent tokens: Leave consistent tokens on to map each unique IP to a stable placeholder, preserving request correlation for analysis. Turn it off for a flat redaction. 3. Copy the anonymized output: Copy the result and send it to your AI tool. Counts of unique IPv4 and IPv6 addresses confirm what was replaced. FAQ: Q: What does it detect? A: Both IPv4 addresses (validated, dotted-quad) and IPv6 addresses including compressed forms. Each is replaced with a bracketed placeholder so the log structure stays intact. Q: What do consistent tokens do? A: With consistent tokens on, the same IP always maps to the same placeholder like [IPv4_3], so you can still group requests by client during analysis. With it off, every address becomes a generic [IPv4] or [IPv6]. Q: Does my log data leave the browser? A: No. All matching runs in your browser. Nothing is uploaded, logged, or stored. Q: Are IP addresses really personal data? A: Yes. Under the GDPR, IP addresses are treated as personal data because they can identify an individual, which is exactly why you should strip them before sending logs to a third-party AI service. Q: Can it misfire on version numbers or other numbers? A: IPv4 detection is strictly validated to 0–255 octets, so most version strings are safe. IPv6 matching is broad by design, so glance over the output if your data contains many colon-separated hex values. #### LLM JSON Repair URL: https://geratools.com/json-repair-llm Paste raw LLM output and get back valid, pretty-printed JSON. Repairs common LLM quirks — trailing commas, single quotes, unquoted keys, markdown fences, smart quotes, and truncated objects or arrays — all in your browser. How to use: 1. Paste the raw output: Drop the model's response into the input box, including any markdown fences or stray prose around the JSON. 2. Let it repair: The tool strips fences, normalizes quotes, removes trailing commas, and closes truncated brackets, then validates the result. 3. Copy the clean JSON: Copy the pretty-printed, valid JSON. If a fix is uncertain, the tool tells you what it changed. FAQ: Q: What kinds of errors does it fix? A: It handles the common LLM failure modes — markdown code fences, leading or trailing prose, single quotes, unquoted keys, trailing commas, smart or curly quotes, and JSON truncated mid-object or mid-array. After repairing it validates with a real parser. Q: How does it handle truncated output? A: When a model gets cut off, the JSON often ends mid-value with unbalanced brackets. The tool tracks open braces, brackets, and strings and appends the closing characters needed to make it parseable, so you recover the partial data instead of nothing. Q: Could a repair change my data's meaning? A: The repairs are syntactic, not semantic — quotes, commas, and brackets — so values are preserved. Truncation recovery is the one case to review, since closing an interrupted structure can drop an incomplete final value. The tool flags when it had to close brackets. Q: Is anything sent to a server? A: No. All parsing and repair happens locally in your browser. Your data never leaves the page. #### JSON Schema → Python Dataclass URL: https://geratools.com/json-schema-to-python-dataclass Generates Python @dataclass definitions from a JSON Schema, with correct Optional, List, and Dict annotations, default values for optional fields, nested dataclass support, and Literal enums. Handy for typed LLM structured-output parsing in Python. How to use: 1. Paste your JSON Schema: Drop a JSON Schema object into the input. Objects, arrays, enums, and nested objects are supported. 2. Name the root class: Set the name for the top-level dataclass. Nested objects become their own dataclasses, declared before they are used. 3. Copy the Python: Review the generated dataclasses and the import line, then copy them into your module. FAQ: Q: What Python features does the output use? A: It emits @dataclass classes with typing-module hints — Optional[T] for non-required fields with a None default, List[T] for arrays, and Literal[...] for string enums. The needed imports (dataclass plus the typing symbols used) are included at the top of the output. Q: How are required vs optional fields handled? A: Fields in the schema's required array are mandatory. Others become Optional[T] with a default of None, and are ordered after required fields so the dataclass is valid. Q: Does it support nested objects? A: Yes. Nested object schemas become separate dataclasses emitted in dependency order, so child classes are defined before the parent references them. Q: Is my schema uploaded? A: No. Generation runs entirely in your browser. Nothing is sent to a server or stored. #### LLM Citation URL Validator URL: https://geratools.com/llm-citation-validator Finds all URLs in LLM output and runs format validation, TLD verification, and pattern checks that flag likely hallucinated links — placeholder hosts, made-up document IDs, and suspicious paths — so you can catch fabricated citations before publishing. How to use: 1. Paste the LLM output: Drop in the answer or report containing the citations you want to verify. 2. Extract and scan: The tool pulls every URL and runs format, TLD, and hallucination-pattern checks on each one. 3. Review the flags: Each URL is labelled OK, malformed, or suspicious, with the reason — open the suspicious ones to confirm they actually resolve. FAQ: Q: Does it actually visit the URLs? A: No. Browsers block cross-origin fetches and HEAD requests to arbitrary sites, so the tool does static validation only — URL syntax, a known top-level-domain check, and heuristics for fabricated links. Use the flags to decide which URLs to open and verify manually. Q: What counts as a hallucination pattern? A: Common tells include placeholder hosts (example.com, your-site), implausibly long random document or article IDs, dates far in the future, repeated identical paths, and uncommon or invalid TLDs. None is proof on its own, but a flagged URL deserves a manual look. Q: Which URL formats are recognized? A: It extracts http and https URLs, including those wrapped in markdown link syntax or parentheses, and strips trailing punctuation. Bare domains without a scheme are detected separately and flagged as needing a protocol. Q: Is my text uploaded? A: No. Extraction and all checks run locally in your browser. Nothing is sent to a server, so you can validate citations in confidential drafts safely. #### LLM Response Formatter URL: https://geratools.com/llm-response-formatter Paste a full LLM API response from OpenAI, Anthropic, or Gemini and instantly extract the message content, token usage, finish reason, and any tool calls — formatted separately and readably. How to use: 1. Paste the raw API response: Copy the full JSON body returned by the chat completions or messages endpoint and paste it into the box. 2. Read the extracted content: The tool detects the provider format automatically and pulls out the assistant message text, displaying it as clean prose instead of escaped JSON. 3. Inspect usage and tool calls: Token usage, finish reason, and any structured tool or function calls are shown in separate sections so you can debug exactly what the model returned. FAQ: Q: Which providers does this support? A: It auto-detects OpenAI chat completions, the Anthropic Messages API, and Google Gemini generateContent responses. It looks for the characteristic fields of each — choices for OpenAI, content blocks for Anthropic, and candidates for Gemini — and falls back gracefully if the shape is unfamiliar. Q: Does my response data leave the browser? A: No. All parsing happens locally in your browser with no network calls. You can safely paste responses that contain private content because nothing is sent anywhere. Q: Why is my message content showing as escaped text? A: Raw API responses store the text with JSON escaping for newlines and quotes. This tool unescapes it and renders real line breaks, so a response that looked like one long string becomes properly formatted paragraphs and code. Q: How are tool calls displayed? A: When the model returns function or tool calls, the tool name and its JSON arguments are extracted into a separate section and pretty-printed, so you can verify the arguments are valid JSON before executing them in your application. #### Markdown → HTML Converter URL: https://geratools.com/markdown-to-html Converts LLM-generated markdown to clean semantic HTML — headings, lists, code blocks, links, tables, blockquotes, bold and italic. Renders a live preview and gives you copyable source, all in the browser. How to use: 1. Paste your markdown: Drop the markdown from an LLM, README, or note into the input box. 2. Review the live preview: The rendered HTML appears instantly so you can confirm headings, lists, and code look right. 3. Copy the HTML source: Switch to the source view and copy clean semantic HTML to paste into your CMS or page. FAQ: Q: Which markdown features are supported? A: Headings (H1–H6), ordered and unordered lists, fenced and inline code, links, images, bold, italic, blockquotes, horizontal rules, and pipe tables. These cover essentially everything an LLM emits. Q: Is the output sanitized? A: The converter escapes raw HTML and angle brackets in your text before emitting tags, so a stray `