How to calculate pool gallons
Find the volume in cubic feet, then multiply by 7.48 gallons per cubic foot. For a pool with a sloped floor, use the average of the shallow and deep depths.
Example: a 32 × 16 ft rectangular pool going from 3.5 ft to 8 ft has an average depth of 5.75 ft: 2,944 cubic feet, or 22,023 gallons. A garden hose at 10 gallons a minute takes about 36.7 hours to fill it.
Why pool volume matters
- Chemicals: chlorine, shock and balancers are dosed per 10,000 gallons. Getting the volume wrong is the most common reason water goes cloudy or harsh.
- Pump size: most pools should turn over all their water in about 8 hours. 22,000 gallons ÷ 480 minutes is about 46 gallons a minute.
- Filling: a water delivery truck is faster than a hose; ask your utility about a sewer credit for filling.
Common above-ground pools: a 24 ft round pool with 48" of water holds about 13,500 gallons. For other volumes, use the cubic yard calculator.
Frequently asked questions
How many gallons is a 24 ft round pool?
About 13,500 gallons at 4 ft of water: 24² × 4 × 5.87. At 52" of water it's about 14,700.
How many gallons in a 16×32 pool?
Roughly 22,000 gallons with a 3.5 to 8 ft depth, or about 19,000 at a uniform 5 ft.
How long does it take to fill a pool with a hose?
Most garden hoses flow 5 to 12 gallons a minute, so a 20,000-gallon pool takes about 1 to 3 days.
Was this calculator helpful?