How many gallons your pool holds, for any common shape, in-ground or above-ground. The same formulas the Pool Predictor Pro app uses.
Measure the water, not the walls. On an above-ground pool, use the water depth, usually about 6 inches less than the wall height. Same depth everywhere? Enter it in both boxes.
Gallons = surface area (sq ft) × average depth (ft) × 7.48. There are 7.48 gallons in a cubic foot of water.
Average depth is the shallow end plus the deep end, divided by 2. For a pool with a long shallow area and a small deep well, nudge the average toward the shallow depth: the simple average overstates the water.
Every chemical dose is sized to your pool's volume. If your estimate is 20% high, every dose you add is 20% too big. It's worth measuring once, carefully, and writing the number down.
Most above-ground pools are filled to about 6 inches below the top of the wall. These figures use that, and the same formula as the calculator.
| Pool | 48 in wall | 52 in wall |
|---|---|---|
| 12 ft round | 3,000 | 3,200 |
| 15 ft round | 4,600 | 5,100 |
| 18 ft round | 6,700 | 7,300 |
| 21 ft round | 9,100 | 9,900 |
| 24 ft round | 11,800 | 13,000 |
| 27 ft round | 15,000 | 16,400 |
| 30 ft round | 18,500 | 20,300 |
| 33 ft round | 22,400 | 24,500 |
| 30 x 15 ft oval | 9,300 | 10,100 |
| 33 x 18 ft oval | 12,200 | 13,400 |
| 41 x 21 ft oval | 17,700 | 19,400 |
| 40 x 24 ft oval | 19,700 | 21,600 |
Next: how much chlorine to add, or getting ready for winter with how to close a pool.
Pool Predictor Pro has this calculator built in, then sizes every dose and forecast to your pool, so you only ever enter your measurements once.
Pool Predictor