Pool Volume Calculator

Pool volume is surface area × average depth in feet, which gives cubic feet; multiply by 7.48 to get US gallons. For a rectangle the surface is length × width; for a round pool it is π × radius². Average depth is the number people get wrong — in a sloping pool it is the shallow and deep depths averaged, not the deepest point.

At an average depth of 5 ft that is 2,560 cubic feet, or about 19,150 gallons — roughly 72,500 liters. A pump moving 50 gallons per minute would cycle the whole volume in about 6.4 hours, which is why single-speed pumps are typically run 8 hours a day and variable-speed pumps much longer at lower flow.

Almost every pool chemical is dosed per 10,000 gallons, so an inaccurate volume means every correction is wrong by the same proportion — and chlorine, acid, and stabilizer are all easier to add than to remove. Get the volume right once, write it on the equipment pad, and use that figure for the life of the pool.

For a kidney or freeform shape, approximate it as a rectangle using the average length and average width, or split it into sections and add them. For a pool that slopes from 3 ft to 8 ft, average depth is 5.5 ft — but only if the slope is roughly even. A pool with a flat shallow end, a short transition, and a deep hopper is better estimated section by section.

Turnover is the time to pass the entire volume through the filter once, and most guidance targets at least one full turnover a day, often two in heavy use or hot weather. It is a proxy, not a guarantee — dead spots behind ladders and steps stay poorly circulated regardless of pump size. Aim returns to push water in a consistent rotation and the whole body mixes far better.