Pool Volume Calculator
Find how many litres or gallons your swimming pool holds — rectangular, round or oval.
Measure inside the pool wall and use the water depth, not the wall height. Steps, benches and rounded corners reduce the real volume slightly. Always dose chemicals by the product label.
About this tool
Calculate the water volume of a rectangular, round, elliptical or straight-sided oval pool in litres, cubic metres and US or UK gallons, plus the surface area and the weight of the water. Use it to dose chemicals, size a pump or heater, or plan filling.
Frequently asked questions
Multiply the surface area by the average water depth. A rectangular 8 × 4 m pool with 1.5 m of water holds 8 × 4 × 1.5 = 48 m³, which is 48,000 litres. In feet, multiply cubic feet by 7.48 to get US gallons.
Use the average depth: (shallow end + deep end) ÷ 2. A pool that is 1 m deep at one end and 2 m at the other has an average depth of 1.5 m, if the floor slopes evenly.
Round: π × radius² × depth — a 4.5 m pool with 1.2 m of water holds about 19,085 litres. A true ellipse uses π × ½L × ½W (≈ L × W × 0.785). Most oval above-ground pools have straight sides: (L − W) × W + π × (W/2)².
Chlorine, pH adjusters and other chemicals are dosed per litre or gallon of water, and pump, filter and heater sizes depend on the volume. Filling time = volume ÷ hose flow rate.
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