Pool Volume Calculator

Almost everything in pool care is dosed per volume of water, so the number that matters most is how many gallons or litres your pool actually holds. Get that wrong and every chemical dose is wrong with it, which is why pool shops ask for the volume before selling you anything, and why an estimate from the pool's dimensions is worth doing properly. The arithmetic is a volume calculation with one refinement: the floor slopes, so the depth varies. For a constant-depth pool, length times width times depth gives the cubic feet, and multiplying by about seven and a half gives US gallons. For a typical pool with a shallow and a deep end, average the two depths before multiplying. A round pool uses the area of a circle, pi times the radius squared, rather than length times width. Real pools rarely match the geometry exactly. Roman ends, steps, a sun shelf, a spa spillover and a sloped floor all remove or add volume relative to a plain rectangular box, so the calculated figure is usually a little generous. Dosing charts handle this with ranges, and it is plainly safer to be slightly over than under on sanitizer, but a heavily shaped pool may hold enough less water to matter — check the builder's original specification if you can find it. This calculator gives volume in cubic feet, US gallons, litres and cubic metres for a rectangular or round pool with a sloped floor. It ignores steps, spas and attached features. Round the result sensibly for dosing, keep a note of the figure near the pump, and use it whenever you adjust chlorine, pH or stabiliser.

This calculator returns estimates for planning and general information only. It is not engineering, architectural, structural, electrical or code advice, and it cannot replace a qualified professional who has seen the site. Material quantities depend on the actual dimensions, the product you buy and local building codes, so confirm the figures before ordering materials or starting work, and always follow local regulations.