Volume Calculator
This volume calculator works out the volume of common 3D shapes and converts it to cubic metres, litres and gallons. For example, a cylinder 1 m across and 1.2 m tall holds 0.942 m³, which is 942 litres or 207 UK gallons.
- 1 m³1,000 litres
- 1 UK gallon4.546 litres
- Cylinderπ × r² × h
Updated November 2026 · Shows the formula and unit conversions
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Volume formulas
| Shape | Formula | Example | Volume |
|---|---|---|---|
| Cuboid | length × width × height | 2 × 1 × 0.5 m | 1 m³ |
| Cube | side³ | 0.5 m sides | 0.125 m³ |
| Cylinder | π × r² × h | 1 m diameter, 1.2 m tall | 0.942 m³ |
| Cone | ⅓ × π × r² × h | 1 m diameter, 1.2 m tall | 0.314 m³ |
| Sphere | 4⁄3 × π × r³ | 1 m diameter | 0.524 m³ |
| Rectangular pyramid | ⅓ × l × w × h | 2 × 2 × 1.5 m | 2 m³ |
Radius (r) is half the diameter. Always convert every measurement to the same unit before multiplying.
Converting cubic metres to litres and gallons
| From | To | Multiply by |
|---|---|---|
| m³ | litres | 1,000 |
| m³ | UK gallons | 219.97 |
| litres | UK gallons | 0.21997 |
| cm³ | litres | 0.001 |
| ft³ | m³ | 0.02832 |
| ft³ | litres | 28.317 |
A UK (imperial) gallon is 4.546 litres. A US gallon is smaller, at 3.785 litres.
How to measure for volume
- For a tank, water butt or pond, measure the inside dimensions to find how much it holds.
- For concrete, soil or gravel, measure the hole or area to fill and add 5 – 10% for waste and settling.
- For an irregular shape, split it into simple shapes, work out each volume and add them together.
Frequently asked questions
How do you calculate volume in m³?
Convert every measurement to metres, then multiply length × width × height for a box. A 2 m × 1 m × 0.5 m box is 1 m³.
How many litres are in a cubic metre?
There are 1,000 litres in 1 m³, which is about 220 UK gallons.
What is the volume of a cylinder?
Multiply π by the radius squared and by the height. A cylinder 1 m across and 1.2 m tall is 3.1416 × 0.5² × 1.2 = 0.942 m³.
How do I work out volume in litres from cm?
Multiply length × width × height in centimetres and divide by 1,000. A 50 × 30 × 40 cm tank holds 60 litres.
How many litres in a UK gallon?
One UK gallon is 4.546 litres. One US gallon is 3.785 litres.
Sources and method
We use official UK guidance and recognised formulas, and test each calculator against worked examples. Results are estimates to help you plan, not professional advice. See how we work.