calcs.homes
calcs.homes
A quick pool gallon size calculator — pick your pool's shape, enter dimensions and average depth, and get gallons right away.
Estimate only — uses standard pool-industry shape constants for average depth.
Each shape multiplies its footprint dimensions by average depth and a constant that converts cubic feet to gallons: rectangle uses length × width × depth × 7.5, round uses diameter² × depth × 5.9, oval uses length × width × depth × 5.9, and kidney/free-form uses length × width × depth × 6.7. Average depth is the shallow-end depth plus deep-end depth, divided by two.
These shape constants are standard pool-industry figures — 7.5 comes from the exact gallons-per-cubic-foot conversion for a true rectangular prism, while the round, oval, and kidney constants build in a correction factor since those shapes hold less water than the same footprint's bounding rectangle. Using average depth instead of just the deep end keeps the estimate realistic for a pool with a sloped floor.
Add the shallow-end depth and the deep-end depth, then divide by two. For a pool that's 3 ft at the shallow end and 6 ft at the deep end, average depth is 4.5 ft.
This tool gives a quick gallons estimate using standard shape constants. For a pool with a distinct shallow and deep end slope, or an above-ground pool preset size, use the pool volume calculator.