28 Precision Tools

Geometry Calculators 2026 - Area, Volume, Circle, Polygon

Free geometry calculators for area, perimeter, circumference, volume, and angles of every common 2D shape and 3D solid. Each result includes the formula, the substituted values, and a worked example so you can copy the working into homework.

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Why use these tools

What makes the geometry category useful

This category groups calculators that solve closely related real-world tasks, so you can move from a quick estimate to a more specific planning tool without restarting the process.

Find the area of circles, triangles, hexagons, octagons, parallelograms, and ellipses

Calculate volume of cubes, cylinders, prisms, pyramids, and rectangular tanks

Convert between radius, diameter, and circumference of any circle in one step

Calculate interior and exterior angles for any regular polygon up to 20 sides

See the geometric formula and the worked substitution beside every result

School and exam revision

Check area, perimeter, and volume answers with formulas you can copy into your written working.

Construction and DIY

Find the area or volume of rooms, slabs, tanks, and ducts before ordering materials.

Design and CAD prep

Calculate exact dimensions for hexagons, octagons, and pyramids when sketching layouts.

All Geometry Calculators

Circle Geometry Theorem Solver

Solve circle theorems step by step.

Polygon Angle Calculator

Find interior and exterior angles of any polygon.

Midpoint and Distance Calculator

Calculate distance and midpoint between two points.

Semicircle Calculator

Find semicircle area, perimeter, and equation.

Hexagonal Pyramid Calculator

Find hexagonal pyramid volume and surface area.

Hexagon Area Calculator

Regular hexagon area from side length.

Octagon Area Calculator

Regular octagon area from side length.

Pentagon Area Calculator

Regular pentagon area from side length.

Parallelogram Area Calculator

Parallelogram area from base and height.

Ellipse Area Calculator

Ellipse area from semi-major and semi-minor axes.

Circle Segment Area Calculator

Area between chord and arc.

Rectangular Prism Volume Calculator

Box volume from length, width, height.

Cube Volume Calculator

Cube volume and surface area from side.

Trapezoidal Prism Volume Calculator

Trapezoidal prism volume from bases and length.

Trapezoidal Prism Surface Area Calculator

Isosceles trapezoidal prism total surface area.

Annulus Area Calculator

Ring area between two concentric circles.

Hexagon Side Calculator

Hexagon side from area or perimeter.

Octagon Dimensions Calculator

All octagon dimensions from side length.

Ellipse Circumference Calculator

Find ellipse perimeter from semi-major and semi-minor axes.

Irregular Pentagon Area Calculator

Find area of any irregular five-sided polygon from coordinate points.

Irregular Hexagon Area Calculator

Find area of any irregular six-sided polygon from coordinate points.

Area of Shaded Region Circle Calculator

Find the shaded ring area between two concentric circles.

Circumference Calculator

Find circle circumference from radius or diameter instantly.

Diameter to Circumference Calculator

Convert diameter to circumference using C = pi x d.

Circumference to Diameter Calculator

Find diameter from a known circumference using d = C / pi.

Radius to Circumference Calculator

Calculate circumference from radius using C = 2 pi r.

Rectangle Volume Calculator

Find cubic volume of any rectangular box from three dimensions.

LxWxH Calculator

Multiply length x width x height to find cubic volume.

Category FAQ

How do I calculate the area of a circle?

Use pi times r squared. For a circle with radius 5, the area is pi times 25, which equals about 78.54 square units. The circle calculator handles diameter and circumference inputs too.

What is the formula for the volume of a cylinder?

Volume equals pi times radius squared times height. A cylinder with radius 4 and height 10 has a volume of pi times 16 times 10, which equals about 502.65 cubic units.

How do I find the interior angles of a regular hexagon?

Each interior angle equals (n minus 2) times 180 divided by n. For a hexagon with n = 6, each angle is (4 times 180) divided by 6, which equals 120 degrees.

How is the circumference of a circle calculated?

Circumference equals 2 times pi times r, or pi times d. A circle with radius 7 has a circumference of 2 times pi times 7, which equals about 43.98 units.

What is the difference between perimeter and circumference?

Perimeter is the total distance around any closed shape. Circumference is the specific term used for circles. Both measure boundary length but apply to different shape families.

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All calculations run locally. Precise geometric calculations with visual explanations.

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