Pool chemicals and heaters are dosed by volume. Cubic feet times 7.48052 equals U.S. gallons. Average depth is (shallow + deep) ÷ 2 when the floor slopes evenly.
Rectangle: L × W × D. Round: πr² × D. Oval: π × (L/2) × (W/2) × D. Kidney: a common contractor estimate is 0.45 × (width A + width B) × length × depth.
Freeform pools may need a site measurement or the original builder’s gallons. This tool is for standard geometric approximations.
A gravel pad under the equipment pad uses the crushed stone calculator. Planting around the deck is the soil calculator.
How this calculation works
Gallons = shape volume in ft³ × 7.48052. Kidney uses 0.45(A+B)LD.