Volume Calculator

Find the volume of a box, cylinder, sphere or cone.

Use any unit; volume is in that unit cubed. Enter centimetres for the litre and gallon figures.

Volume
In litres (if cm)
In US gallons (if cm)
Formula
Shape

Round shapes take the radius (half the diameter). Keep all dimensions in the same unit.

Four everyday solids

Most containers and objects reduce to a box, cylinder, sphere or cone. Each has a tidy formula, and all share the same idea: volume grows with the cube of length, so small size changes have big effects.

Boxl × w × h
Cylinderπ r² h
Sphere4⁄3 π r³
Cone1⁄3 π r² h

Work in centimetres and the calculator also reports litres and US gallons, since one litre is exactly 1,000 cubic centimetres.

Worked example

A box 10 × 10 × 10 cm holds 1,000 cm³ — exactly 1 litre, or about 0.26 US gallons. A cylinder of the same height and 10 cm radius holds π × 10² × 10 ≈ 3,142 cm³.

Volume in real life

From sizing a fish tank or planter to estimating concrete for a footing or water in a pipe, volume is the quiet workhorse of practical maths. The cube relationship is the thing to remember: doubling a sphere’s radius multiplies its volume eightfold.

Worth remembering

  • Cone = ⅓ cylinder. Same base and height, a third of the volume.
  • Use the radius. Halve the diameter for round shapes.
  • 1 litre = 1,000 cm³. The easy bridge to capacity.

Frequently asked questions

What units does it use?
Any length unit, as long as you are consistent; the volume comes out in that unit cubed. Enter centimetres and the litre and gallon conversions shown will be correct (1 litre = 1,000 cm³).
What are the formulas?
Box = length × width × height; cylinder = πr²h; sphere = 4⁄3 πr³; cone = 1⁄3 πr²h. The cone is exactly one third of a cylinder with the same base and height.
Radius or diameter for round shapes?
These take the radius — half the diameter. If you measured across the full width, divide by two before entering it.
How do I get US gallons?
One US gallon is about 3.785 litres. Enter your dimensions in centimetres and the calculator converts the volume to litres and gallons for you.