Pool Volume Calculator — How Many Gallons?
Pick your pool shape, enter the size and the shallow- and deep-end depths, and get how many gallons your pool holds.
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How it works
gallons = length × width × shape factor × avg depth × 7.48; avg depth = (shallow + deep) ÷ 2
Gallons in a round above-ground pool
| Pool size (diameter) | 48-in wall (~4 ft water) | 52-in wall (~4.4 ft water) |
|---|---|---|
| 12 ft round | ~3,400 gal | ~3,700 gal |
| 15 ft round | ~5,300 gal | ~5,800 gal |
| 18 ft round | ~7,600 gal | ~8,400 gal |
| 21 ft round | ~10,400 gal | ~11,400 gal |
| 24 ft round | ~13,500 gal | ~14,900 gal |
| 27 ft round | ~17,100 gal | ~18,800 gal |
| 30 ft round | ~21,200 gal | ~23,300 gal |
Above-ground pools fill a few inches below the rail, so water depth is a bit less than the wall height — these assume about 4 ft (48-in wall) and 4.4 ft (52-in wall) of water. For an exact number, enter the diameter for both length and width above.
Frequently asked questions
How many gallons is a 24-foot round pool?
A 24 ft round above-ground pool holds roughly 13,500 gallons with a 48-inch wall (about 4 ft of water) and about 14,900 gallons with a 52-inch wall. Filling a few inches below the rail, as you should, gives slightly less.
How many gallons is an 18-foot or 15-foot round pool?
An 18 ft round holds about 7,600 gallons and a 15 ft round about 5,300 gallons with a 48-inch wall. A 52-inch wall adds roughly 10%, so about 8,400 and 5,800 gallons.
How do I calculate the gallons in my pool?
Multiply the surface area by the average depth and by 7.48 gallons per cubic foot. For round pools, surface area is 0.785 × diameter²; for rectangles it is length × width. Average depth is (shallow + deep) ÷ 2. The calculator above does this for any shape.