Construction Calculator - Water and Utility

Round Pool Volume Calculator

Estimate round pool volume in gallons.

Reviewed: August 26, 2026

Round swimming pool measured across its diameter with a depth staff in the water
Measure the inside diameter at the waterline and use a representative average water depth.

Calculate Round Pool Volume

For the Round Pool Volume Calculator, enter diameter and average water depth. It models a round pool from inside diameter and average water depth, then reports cubic feet, U.S. gallons, and liters.

Formula used

Pool volume = π × (inside diameter ÷ 2)² × average depth; U.S. gallons = cubic feet × 7.48052

Round Pool Volume Calculator measurement plan showing Diameter feet, Average water depth feet

Worked round pool volume example

Round Pool Volume Calculator example: π × (20.2 ft ÷ 2)² × 4.11 ft = 1,317.15 ft³. Multiplying by 7.48052 gives approximately 9,853 U.S. gallons.

Interpret gallons and flow

Use the result for rough operating volume and confirm capacity before chemical dosing, heater selection, or turnover calculations.

System effects the formula omits

Sloped bottoms, a deep well, steps, benches, curved walls, freeboard, and manufacturer stated capacity change actual gallons.

Questions specific to this calculation

Which dimensions should I measure inside a round pool?

Enter inside waterline diameter and average water depth for a circular pool; the formula treats the pool as a vertical cylinder.