This water volume calculator works out how much water a tank, pool, pond or container holds. Enter the shape and dimensions and it gives the capacity in litres, cubic metres and gallons in an instant.
This water volume calculator works out how much water a container holds from its shape and dimensions. It handles rectangular tanks and pools as well as round or cylindrical containers, and converts the result into litres, cubic metres and gallons so you can size a pump, dose a treatment or fill a pond with confidence.
| From | Equals |
|---|---|
| 1 cubic metre (m³) | 1,000 litres |
| 1 litre | 0.22 UK gallons |
| 1 UK (imperial) gallon | 4.55 litres |
| 1 US gallon | 3.79 litres |
| 1 cubic foot | 28.3 litres |
A rectangular tank 2 m long, 1 m wide and 1.2 m deep holds 2 × 1 × 1.2 = 2.4 m³, which is 2,400 litres (about 528 UK gallons). For a round water butt 0.6 m across and 1 m tall the volume is π × 0.3² × 1 ≈ 0.283 m³, or roughly 283 litres. This water volume calculator does these sums for you and shows every unit at once.
Working with water? See the pool volume calculator, the pond liner calculator and the pipe sizing calculator.
This water volume calculator multiplies the container dimensions (length × width × depth, or π × radius² × depth for round shapes) to get the volume, then converts it into litres, cubic metres and gallons so you can read whichever unit you need.
1 cubic metre = 1,000 litres exactly.
Multiply the internal length, width and depth (or use the radius for round tanks), then convert to litres or gallons – which this water volume calculator does automatically.
Multiply length × width × average depth. For irregular shapes, split the pool into sections and add the volumes together.
A UK (imperial) gallon is about 4.55 litres and a US gallon is about 3.79 litres. The calculator shows gallons alongside litres so there is no confusion.