How to use the pool volume calculator
- Pick the shape that matches your pool: rectangle, round, oval or kidney.
- Choose units. Enter feet and inches, or switch to meters. Values convert when you switch.
- Enter the depth. Use one average depth, or choose “Shallow + deep end” and enter both.
The pool gallons calculator updates as you type and shows US gallons, liters, cubic feet and cubic meters, plus the exact formula it used, so you can check the math yourself.
Pool volume formulas
| Shape | Volume (cubic feet) |
|---|---|
| Rectangle | length × width × average depth |
| Round | π × (diameter ÷ 2)² × average depth |
| Oval | π × (length ÷ 2) × (width ÷ 2) × average depth |
| Kidney (estimate) | 0.45 × (A + B) × length × average depth |
Then convert: gallons = cubic feet × 7.48052. In metric, the volume comes out in cubic meters, and liters = cubic meters × 1,000.
Worked examples
- Rectangular in-ground pool, 32 × 16 ft, 3 ft 6 in shallow end and 8 ft deep end: average depth 5.75 ft → 2,944 ft³ → about 22,023 gallons.
- 24 ft round above ground pool, water 4 ft deep: π × 12² × 4 ≈ 1,810 ft³ → about 13,536 gallons.
- Oval above ground pool, 15 × 30 ft, 4 ft of water: π × 7.5 × 15 × 4 ≈ 1,414 ft³ → about 10,575 gallons.
Why your pool’s volume matters
Chemical doses on chlorine, shock, pH and salt labels are given per gallon (often per 10,000 gallons), so a good estimate keeps the water balanced without wasting product. Volume also helps you size a pump and filter (turnover time), a heater, and plan a fill-up or water delivery.
Measuring tips: measure the inside of the pool wall, measure water depth rather than wall height, and for above ground pools remember most are filled to about the middle of the skimmer, not to the top.
Frequently asked questions
How do I calculate how many gallons are in my pool?
Find the volume in cubic feet (for a rectangle: length × width × average depth), then multiply by 7.48052, the number of US gallons in one cubic foot. A 32 × 16 ft pool with a 5 ft average depth is 2,560 cubic feet, or about 19,150 gallons.
How do I measure the depth of a pool with a shallow and deep end?
Measure the depth at the shallow end and at the deep end, then use the average of the two. Choose “Shallow + deep end” in the calculator and it averages them for you. This works well for a steady slope; pools with a steep drop-off or a large flat deep area may hold a bit more or less.
How do I find the volume of an above ground pool?
Most above ground pools are round or oval. Measure the inside diameter (or the length and width for an oval) and the water depth, not the wall height, since pools are not filled to the very top. Pick Round or Oval above and enter those numbers.
How accurate is the kidney pool calculation?
Kidney pools are irregular, so the calculator uses the common estimate 0.45 × (A + B) × length × average depth, where A and B are the widths at the widest and narrowest ends. Treat the result as a close estimate, not an exact figure.
How many liters are in a gallon?
One US gallon is exactly 3.785411784 liters, and one cubic meter of water is 1,000 liters. The calculator shows both US gallons and liters.