Calculate the water volume of a swimming pool in litres and gallons for rectangular, round and oval pools.
Select the pool shape, enter the dimensions and the average water depth, and the tool returns the volume in gallons (US) and litres. Knowing the volume lets you dose chemicals correctly and size a pump or heater.
If your pool has a shallow and a deep end, use the average of the two — a pool that is 3 ft at one end and 7 ft at the other has an average depth of 5 ft.
| Conversion | Value |
|---|---|
| 1 m³ | 1,000 litres |
| 1 m³ | 264 US gallons |
| 1 US gallon | 3.785 litres |
A rectangular pool 10 m × 4 m with an average depth of 1.5 m holds 10 × 4 × 1.5 = 60 m³ = 60,000 litres ≈ 15,850 US gallons.
Tip: round-up when dosing chemicals — it is safer to base doses on the full volume than to under-treat the water.
Calculate the volume in cubic metres, multiply by 1000 to get litres, then divide by 3.785 for US gallons or 4.546 for imperial gallons.
You need it to dose chemicals correctly, size a pump and heater, and estimate water and heating costs.
Add the shallow-end depth and the deep-end depth and divide by two for a simple average.
Multiply the surface area by the average depth. The calculator handles rectangular, round and oval pools and converts to litres and gallons.
Divide the pool volume by your hose flow rate. A typical garden hose delivers about 10–20 litres a minute, so a large pool can take many hours or even a day or two to fill.
