Calculate above-ground pool volume in gallons, or use our size chart for standard round and oval kits. Free.
If you know your pool’s surface area, you can enter it directly instead of the diameter or dimensions. Switch to “I know my surface area”, type in the square footage, and set your water depth — useful if your pool isn’t a standard kit size.
π × radius² × Water Depth × 7.48 = US gallons
Above-ground pools are rarely filled to the rim. A 52-inch wall typically holds about 46–48 inches of water. Use the water depth for an accurate number.
This calculator uses the precise cubic-foot-to-gallon value (about 7.48 US gallons per cubic foot) for your above-ground pool and lets you switch between US gallons, imperial gallons, litres, and cubic metres.
Approximate water capacity for standard above-ground kits, filled to about 48 inches of water in a 52-inch wall. Your exact figure depends on how high you fill the pool — use the calculator above for precision.
| Size | Approx. volume |
|---|---|
| 12 ft round | 3,384 gal |
| 15 ft round | 5,288 gal |
| 18 ft round | 7,614 gal |
| 21 ft round | 10,364 gal |
| 24 ft round | 13,536 gal |
| 27 ft round | 17,132 gal |
| 30 ft round | 21,151 gal |
| 33 ft round | 25,592 gal |
| Size | Approx. volume |
|---|---|
| 12 × 24 ft oval | 6,768 gal |
| 15 × 26 ft oval | 9,165 gal |
| 15 × 30 ft oval | 10,575 gal |
| 18 × 33 ft oval | 13,959 gal |
A 52-inch wall does not mean 52 inches of water. Most above-ground pools are filled to roughly the middle of the skimmer, about 46–48 inches. Filling to the full wall height overstates volume by 8–10%.
You will need these measurements:
A 24 ft round pool filled to 4 ft: radius 12 ft, π × 12² × 4 = 1,810 cubic feet, then × 7.48 ≈ 13,536 US gallons.
The mistake that throws off round-pool volume most is using the wall height instead of the actual water depth. A round above-ground pool with a 52-inch wall is rarely filled to the top — water usually sits around 46–48 inches, below the skimmer cut-out. Always measure from the floor to the real waterline. Measure the diameter straight across the widest point through the center; measuring a chord that misses the center understates the diameter and, because area depends on the radius squared, even a small diameter error has an outsized effect on the result. Round pools are uniform depth, so there is no shallow-and-deep average to worry about — just one honest water depth.
The method behind this calculator draws on established standards, peer-reviewed academic sources, and reference values:
Results are planning estimates. Where a figure depends on your local rates, codes, or site conditions, confirm with the cited authority or a qualified professional.