Gallons in a rectangle, round or oval pool from its size, with a sloped floor.
How it works
Measure the water, not the deck: inside length and width, and the depth at the shallow and the deep end.
Gallons = length × width × average depth × 7.48 (one cubic foot holds 7.48 gallons). Round pools: 3.1416 × (diameter ÷ 2)² × depth × 7.48; ovals: 0.785 × length × width × depth × 7.48.
Example: 32 × 16 ft, 3.5 to 6.5 ft deep: average 5 ft, 2,560 ft³ → about 19,150 gallons. A 24 ft round above-ground pool 4 ft deep holds about 13,536 gallons.
Frequently asked questions
How many gallons are in my pool?
Multiply length × width × average depth in feet, then × 7.48. That is the number every dose depends on.
How do I find the average depth?
Add the shallow and the deep depth and divide by 2. For a hopper-bottom pool this slightly overestimates; that’s fine for dosing.
How many gallons in a 24 ft round pool?
At 4 ft of water about 13,536 gallons; at 52 inches about 14,664.