Estimate the volume of your pool in gallons. Choose the shape, enter the dimensions and average depth, and the calculator converts to gallons. Each dimension has its own unit selector (in/ft/yd/m).
Pool volume in gallons starts with the water volume in cubic feet, then converts at 7.48 gallons per cubic foot. First find the surface area: length times width for a rectangle, pi times the radius squared for a round pool, or pi times the half-length times the half-width for an oval. The unit selector converts inches, feet, yards or meters for you.
Multiply the area by the average depth—for a pool that slopes from shallow to deep, that is the shallow plus deep depth divided by two. The result in cubic feet times 7.48 gives gallons. Knowing your gallons is essential for dosing chemicals, sizing a pump and heater, and ordering a liner.