Enter pool dimensions and shallow and deep depths for a rectangular, round, oval or kidney pool to get its volume in US gallons and litres.
Round pools: enter the diameter in the Width field; Length is ignored. All dimensions are in feet.
Volume is worked out from the surface area multiplied by the average depth, where average depth is the shallow depth plus the deep depth divided by two. Rectangular pools use length times width, round pools use the circle area from the diameter, and oval pools use the ellipse area from length and width. The kidney shape uses the standard approximation factor: surface area is estimated as length times width times 0.45, so kidney results are an approximation rather than an exact figure. Cubic feet are converted at 7.48052 US gallons per cubic foot, and litres are converted from gallons.
How is average depth calculated for a sloped pool floor? Average depth is the shallow depth plus the deep depth divided by two. That average multiplied by the surface area gives a close volume for a pool with a steady slope.
Is the kidney pool result exact? No. Kidney shapes vary, so the standard 0.45 approximation factor is used for the surface area and the result is labelled an approximation. Measuring the actual surface area gives a closer figure.