Business & Marketing
51 free business & marketing tools in the Calculators & Converters collection — every one runs in your browser with no signup and no uploads.
Aldosterone-to-Renin Ratio (ARR) Calculator
Screen for primary aldosteronism from aldosterone and renin
Bone Marrow Blast Percentage Calculator
Calculate blast % from a differential count for AML/MDS diagnosis
Bow Arrow Kinetic Energy & FOC Calculator
Calculate arrow kinetic energy, momentum, and front-of-center balance.
D&D Ability Score Optimizer
Arrange D&D standard array or rolled stats for any class
D&D Carrying Capacity Calculator
Know exactly how much your D&D character can carry
Electrical Apprentice NEC Code Study Calculator
Practice NEC load problems with step-by-step solutions and a running score.
Electrical Conduit Bending Calculator
Stub-up, 90, offset, saddle, and back-to-back bend marks for EMT and rigid
Electricity Cost Calculator
Calculate daily, monthly and annual electricity cost for any load from wattage and utility rate.
Electrical Demand Charge Calculator
Estimate monthly demand charges from peak kW and find peak-shaving savings
Fuse vs. Circuit Breaker Comparison Tool
Compare clearing times of current-limiting fuses and breakers at any fault multiple.
Grounding & Bonding Checklist Generator (NEC 250)
Generate a site-specific NEC Article 250 grounding and bonding checklist
Electrical Panel Load Audit Tool
Flag overloaded circuits, undersized conductors, and missing AFCI/GFCI per NEC 2023
Electrical Permit Load Summary Generator
Generate a permit-ready load summary sheet for AHJ submission from circuit data.
Electrical Safety Clearance Distance Calculator
Look up NFPA 70E shock approach boundaries for qualified and unqualified workers
Electricity Grid Carbon Intensity Tool
Look up CO2 per kWh for 40+ national electricity grids
Electrophoresis DNA Ladder Band Size Estimator
Estimate band sizes from gel image using ladder migration distances
FM Synthesis Carrier:Modulator Ratio Calculator
Find harmonic and inharmonic C:M ratios for FM synthesis timbres
Grounding Electrode System Resistance Calculator
Estimate ground-rod resistance with the Dwight formula for single and parallel rods.
IPG Strip pH Range Selector for 2D-PAGE
Match protein pI to the correct IEF strip pH range for 2D electrophoresis
LDR Voltage Divider Calculator for DIY Electronics
Calculate the series resistor value for a light-dependent resistor voltage divider
Peptide Molecular Weight & Isoelectric Point Calculator
Compute MW and pI from a one-letter amino acid sequence
Nutritional Requirements Calculator (Harris-Benedict / Mifflin)
Total daily energy and protein needs for clinical nutrition
Runway Length Required Calculator
Estimate factored takeoff and landing field lengths from performance inputs
Solar Array Tilt & Azimuth Output Calculator
Estimate how tilt angle and compass orientation change a PV array's annual energy yield.
Solar Array Shading Loss Estimator
Estimate annual PV energy loss from a tree, ridge, or chimney by sun-path geometry
Spectrophotometry Absorbance to Concentration Calculator
Apply Beer-Lambert for single readings or a standard curve
Stick Electrode Selection Guide
Match SMAW electrode type to base metal, joint position, and penetration need
TikTok Engagement Rate Calculator
Calculate true TikTok engagement rate the way brands measure it.
Water Hammer Arrestor Sizing Calculator
Select a water hammer arrestor size (A–F) per PDI-WH 201 by fixture load
Meat Roasting Time Calculator
Roasting times and safe internal temperatures by weight and doneness.
Electricity Bill Estimator
Turn watts and hours into a daily, monthly and yearly cost.
Contribution Margin Calculator
Instantly find your CM per unit, CM ratio, break-even point and operating leverage.
EBITDA Calculator
Calculate EBITDA, margins, EV/EBITDA, and key leverage ratios instantly.
Economic Order Quantity (EOQ) Calculator
Find the optimal order size that minimises total inventory cost.
Payback Period Calculator
Find how long until your investment breaks even — simple and discounted methods.
Return on Assets (ROA) Calculator
Measure how efficiently a business turns its asset base into profit.
Return on Equity Calculator
Calculate ROE — basic, DuPont 3-factor and DuPont 5-factor decomposition.
Working Capital Calculator
Measure liquidity: current ratio, quick ratio, cash conversion cycle and more.
Electric Field Calculator
Solve E = k·Q/r², V = k·Q/r, F = qE and Gauss's Law with full working shown.
Photoelectric Effect Calculator
Calculate KE, stopping voltage, threshold frequency and wavelength using Einstein's equation KE = hf − φ.
MRR Calculator
Calculate Monthly Recurring Revenue, ARR, LTV and forward projections.
A/B Test Significance Calculator
Know whether your experiment result is real — two-proportion z-test with p-value, confidence interval and power check.
ARR Calculator
Calculate Annual Recurring Revenue, NRR, GRR and MRR bridge in seconds.
CAC Payback Period Calculator
Find out how many months it takes to recover your customer acquisition cost.
Cost Per Acquisition (CPA) Calculator
Calculate CPA, LTV, ROAS, CTR, payback period and campaign ROI in one place.
CPC Calculator — Cost Per Click, CTR, ROAS & CPA
Work out your CPC, CTR, CPM, CPA, ROAS and campaign profit in one place.
CPM Calculator
Calculate CPM, total ad spend, or impressions — plus CTR, CPC, CPL and ROAS.
ROAS Calculator
Calculate Return on Ad Spend — instantly see ROAS, break-even, POAS and net profit.
Startup Runway Calculator
See exactly how many months of cash you have left — and when revenue covers burn.
Monthly Active Users (MAU) Calculator
Track MAU growth, churn, stickiness and 30-day retention across multiple periods.
Viral Coefficient Calculator
Calculate K-factor and model exponential growth wave by wave.