About this calculator
Water capacity of a pool, pond or hot tub, for chemical dosing, heater and pump sizing, and fill costs.
How it’s calculated
Volume = surface area × average depth. Average depth = (shallow + deep) ÷ 2. 1 m³ = 1,000 litres.
Worked example
With these inputs:
- Shape
- Rectangle
- Length / diameter
- 10 m
- Width
- 5 m
- Shallow end depth
- 1 m
- Deep end depth
- 2 m
the result is:
- Water volume
- 75,000 L
- Surface area
- 50 m²
- Average depth
- 1.5 m
- US gallons
- 19,813
Tips from the trade
- Follow chemical labels against this volume. Never guess a dose.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and the Building Regulations before ordering.