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.