Geometry
42 free geometry tools in the Calculators & Converters collection — every one runs in your browser with no signup and no uploads.
CO2 Cylinder Duration Calculator
Estimate how long a CO2 cylinder will last in your planted tank
Bokeh Circle of Confusion Size Calculator
Calculate the physical diameter of bokeh discs at any aperture and distance
Climbing Grade Pyramid Builder
Build a training-aligned climbing grade pyramid for your level.
Lightning Protection Rolling Sphere Calculator
Determine air terminal zones of protection per the NFPA 780 rolling sphere method.
Shell Thickness & Perimeter Calculator
Calculate total shell thickness from perimeter count and line width
Circle of Fifths Key Relationship Tool
Find relative and parallel keys, borrowed chords, and modulation paths
Circle of Confusion Calculator
Find the right circle of confusion for your sensor and viewing setup
Refrigerant Recovery Cylinder Capacity Calculator
Check recovery cylinder remaining capacity without exceeding the 80% fill limit
Circle Calculator
Radius, diameter, circumference and area from any one value.
Triangle Calculator
Area, perimeter and angles from three side lengths.
Pythagorean Theorem Calculator
Solve a² + b² = c² for the hypotenuse or a missing leg.
Body Surface Area Calculator
BSA in m² by Du Bois, Mosteller and Haycock formulas.
Sphere Calculator
Volume and surface area of a sphere from its radius.
Cone Calculator
Volume, surface area and slant height of a right circular cone.
Cylinder Calculator
Volume and surface area of a right circular cylinder.
Pyramid Calculator
Volume and surface area of a rectangular-base pyramid.
Trapezoid Calculator
Area, perimeter and midsegment of a trapezoid.
Ellipse Calculator
Area, perimeter, eccentricity and axes of an ellipse.
Hexagon Calculator
Area, perimeter, diagonals and apothem of a regular hexagon.
Sector & Arc Calculator
Arc length, sector area and chord from radius and angle.
Right Triangle Trig Solver
Solve any right triangle from two known values — sides and angles.
Law of Cosines Calculator
Solve any triangle from three sides or two sides and an angle.
Pentagon Calculator
Area, perimeter, diagonal and radii of a regular pentagon.
Octagon Calculator
Area, perimeter, diagonals and radii of a regular octagon.
Rhombus Calculator
Area, perimeter, diagonals and angles of a rhombus.
Regular Polygon Calculator
Area, perimeter, radii and angles for any regular n-gon.
Annulus Calculator
Area, width and circumferences of a ring between two circles.
Ramp Slope Calculator
Angle, percent grade, rise/run ratio and ADA compliance — instantly.
Rise Over Run Calculator
Slope, angle, grade and pitch from any rise and run — or solve in reverse.
Equilateral Triangle Calculator
Instantly find side, height, area, perimeter, inradius and circumradius — solve from any one value.
Right Triangle Calculator
Solve any right triangle from two known values — sides, angles, area and trig ratios instantly.
Slope-Intercept Calculator
Find the equation y = mx + b from two points, solve for x or y, and see the diagram.
Circle Diameter Calculator
Find diameter, radius, circumference and area — solve from any one value.
Triangle Angle Calculator
Find every angle and side of any triangle from three known values.
Circle Equation Calculator
Find the standard form, general form, area, arc length, chord and sector — instantly.
Heron's Formula Calculator
Find the area of any triangle from its three side lengths — no angles needed.
Law of Sines Calculator
Solve any triangle from two angles + one side, or two sides + an opposite angle.
Circle Circumference Calculator
Circumference from radius, diameter or area — solve any way around.
Diagonal of a Rectangle Calculator
Find the diagonal, width, height, angles, area and perimeter — with full step-by-step working.
Law of Cosines Solver
Solve any triangle from any three pieces — all five congruence cases with full step-by-step working.
Perimeter Calculator
Instantly find the perimeter of 14 shapes with step-by-step working.
Unit Circle Calculator
Enter any angle and instantly read sin, cos, tan, csc, sec, cot — with a live diagram.