Find how much water a pool, pond, tank or aquarium holds — in gallons, liters and cubic feet, with fill time from a flow rate.
How this calculator arrives at its answer
Choose a rectangular or round shape, enter the dimensions, and this water calculator returns US gallons, liters, imperial gallons and cubic feet. Add a flow rate to estimate how long it takes to fill.
It’s handy for pools, ponds, stock tanks, aquariums and any container where you need to know the volume.
How to fill it in
- Pick rectangular or round and enter the dimensions and depth.
- Read the gallons and liters at the top.
- Enter a fill rate in gallons per minute to estimate fill time.
Formula reference
rectangular (ft³) = length × width × depth
round (ft³) = π × (diameter ÷ 2)² × depth
gallons = ft³ × 7.48 · fill time = gallons ÷ flow rate
A worked example
Worked through, a length of 12, width of 6, diameter of 15 produces a water volume of 2,154.4. Underneath, US gallons comes out at 2,154.4 and Liters at 8,155. Change any field and every figure updates as you type.
Questions people ask about this
How many gallons in a cubic foot of water?
About 7.48 US gallons, 6.23 imperial gallons, or 28.3 liters.
How do I find pool volume?
For a rectangular pool use length × width × average depth. For a round pool use the round shape and enter the diameter.
How long to fill from a garden hose?
A typical hose runs 9–17 gallons per minute. Enter your flow rate and the calculator estimates the fill time.