What is my pool’s volume?
Pick the shape of your pool and enter its inside size and water depths. See how many gallons it holds, and the same volume in litres and cubic feet.
- Water
- 18,193 gal
The pool holds about 18,193 gal of water.
- Litres
- 68,867 L
- Cubic feet
- 2,432 ft³
- Cubic metres
- 68.87 m³
- Average depth
- 4.75 ft
Water: 18,193 gal. The pool holds about 18,193 gal of water.
How to calculate
Computes the water volume of a rectangular, round or oval pool from its length, width or diameter and its shallow and deep end depths, in US gallons, litres, cubic feet and cubic metres.
Example with the default inputs (Shape Rectangle, Length 32 ft, Width 16 ft, Shallow end depth 3.5 ft, Deep end depth 6 ft): The pool holds about 18,193 gal of water.
Method: volume = surface area × (shallow depth + deep depth) ÷ 2; rectangle: length × width; round: π × diameter² ÷ 4; oval: π × length × width ÷ 4
- The floor slopes evenly from the shallow end to the deep end, so the average depth is the mean of the two. A hopper or a sharp break in the floor changes the volume.
- An oval is a true ellipse. Pools with straight sides and round ends hold more.
- Sizes are inside the walls, and depths are to the water line, not the top of the wall.
- Gallons are US gallons of 231 cubic inches.
Worked examples
Each example is checked against the calculator on every build.
- Shape Rectangle, Length 32 ft, Width 16 ft, Shallow end depth 3.5 ft, Deep end depth 6 ft gives Cubic feet 2,432 ft³, Water 18,193 gal.Source: hand calculation in content.mdx: 32 × 16 × (3.5 + 6) ÷ 2 = 2,432 ft³ × 1,728 ÷ 231 = 18,193 gal
- Shape Round, Diameter 24 ft, Shallow end depth 4 ft, Deep end depth 4 ft gives Cubic feet 1,809.6 ft³.Source: hand calculation in content.mdx: π × 24² ÷ 4 × 4 = 576π = 1,809.6 ft³ = 13,536 gal
- Shape Oval, Length 30 ft, Width 15 ft, Shallow end depth 4.5 ft, Deep end depth 4.5 ft gives Cubic feet 1,590.4 ft³.Source: hand calculation in content.mdx: π × 30 × 15 ÷ 4 × 4.5 = 1,590.4 ft³ = 11,897 gal
- Shape Rectangle, Length 32.81 ft, Width 16.4 ft, Shallow end depth 3.937 ft, Deep end depth 5.906 ft gives Cubic metres 75 m³, Litres 75,000 L, Water 19,813 gal.Source: hand calculation in content.mdx: 10 × 5 × (1.2 + 1.8) ÷ 2 = 75 m³ = 75,000 L = 19,813 gal
How it works
- Surface area:
- Rectangle: length × width.
- Round: π × diameter² ÷ 4.
- Oval (an ellipse): π × length × width ÷ 4.
- Average depth = (shallow end depth + deep end depth) ÷ 2. This assumes the floor slopes evenly from end to end.
- Volume = surface area × average depth.
- Gallons = cubic feet × 1,728 ÷ 231 (US gallons). Litres = cubic metres × 1,000.
Use the inside size of the pool and the depth to the water line. A pool with a hopper (a deep, steep-sided pit) holds a little more than this.
Worked examples by hand
A 32 ft × 16 ft rectangle, 3.5 ft to 6 ft deep. Average depth (3.5 + 6) ÷ 2 = 4.75 ft. 32 × 16 × 4.75 = 2,432 ft³. 2,432 × 1,728 ÷ 231 = 18,192.6, about 18,193 gallons.
A round pool 24 ft across, 4 ft deep. π × 24² ÷ 4 = 452.39 ft². × 4 = 1,809.6 ft³ = 13,536 gallons.
An oval 30 ft × 15 ft, 4.5 ft deep. π × 30 × 15 ÷ 4 = 353.43 ft². × 4.5 = 1,590.4 ft³ = 11,897 gallons.
A 10 m × 5 m pool, 1.2 m to 1.8 m deep. Average depth 1.5 m. 10 × 5 × 1.5 = 75 m³ = 75,000 L, or 75,000 ÷ 3.785411784 = 19,813 gallons.
Other questions people ask
How do I calculate how many gallons are in my pool?
Work out the volume in cubic feet, then multiply by 7.48, the number of US gallons in a cubic foot (1,728 ÷ 231). A 32 ft × 16 ft pool with an average depth of 4.75 ft holds 2,432 ft³, or about 18,193 gallons.
How do I handle a shallow end and a deep end?
Average the two depths: (shallow + deep) ÷ 2. This assumes the floor slopes evenly. For a flat floor, enter the same depth twice.
How do I calculate a round pool?
Multiply π × diameter² ÷ 4 by the depth. A 24 ft round pool 4 ft deep is π × 576 ÷ 4 × 4 = 1,809.6 ft³, or about 13,536 gallons.
Why does the pool volume matter?
Pool chemicals are dosed per volume of water, and heaters, pumps and filters are sized by it. The label on a chemical tells you the dose per 10,000 gallons or similar; follow it with your pool’s volume.
Should I measure to the top of the wall?
No. Measure the depth to the water line, and the length and width inside the walls. Measuring to the top of the wall overstates the water.
How many litres are in a US gallon?
A US gallon is exactly 3.785411784 litres. 1 cubic metre is 1,000 litres, or about 264.2 US gallons.