Pool Volume Calculator: Rectangular (Gallons)

Gallons in a rectangular pool with a sloped bottom, using average depth.

Formula

Gallons = L × W × (shallow + deep)/2 × 7.48052 gal/cu ft.

Worked example

Inputs: Length = 32 ft; Width = 16 ft; Shallow-end depth = 3.5 ft; Deep-end depth = 6 ft.

Gallons	18,193
Liters	68,867

FAQ

Why does volume matter?

Chemical dosing and pump/heater sizing are specified per gallon.

Sources

Geometry (volume/area formulas); no external constant needed
NIST: 1 US gallon = 231 cubic inches (7.48052 gal per cubic foot)

Related

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Last reviewed 2026-10-11.