Area & Volume Calculator

Pick a shape, enter its sizes and get area, perimeter, surface area or volume with a diagram.

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Area & Volume Calculator

Flat shapes and solids with diagrams and formulas

Shape

Unit of length

Sizes

Length

Width

Area40 cm²0.004 m² · 0.0431 sq ft

Perimeter26 cm

Diagonal9.434 cm

How it works

Area is the flat space inside a shape, perimeter is the distance around it, surface area is the total area of the outside of a solid, and volume is the space inside it.

Units: cm
Areas are in square cm (cm²) and volumes in cubic cm (cm³). All sizes must use the same unit.

Area = length × width = 8 × 5 = 40
Perimeter = 2 × (length + width) = 2 × (8 + 5) = 26
Diagonal = √(length² + width²) = 9.43398

Use one unit for every size; the results then come out in that unit squared or cubed.
To fill a tank or box, the litres figure shows the capacity (1 litre = 1,000 cm³).
For land and flooring in India, the square feet figure under the area is handy.

Standard textbook formulas, evaluated in double precision with π = Math.PI. The triangle from three sides uses Heron's formula in a numerically stable form. The ellipse perimeter uses Ramanujan's second approximation. Conversions use 1 ft = 0.3048 m and 1 m³ = 1,000 L.

Preparing tool

How to use Area & Volume Calculator

Choose a flat shape or a solid.
Enter its sizes and pick the unit (cm, m, ft and more).
Read the results, check the labelled diagram and see each formula with your numbers.

Read the detailed guide →

What are the limits of Area & Volume Calculator?

Drawings are schematic and not exactly to scale. The ellipse perimeter uses Ramanujan's approximation, which has no simple exact formula. Shapes are the standard regular ones; irregular shapes are not covered. Nothing you enter leaves your device.