Pool Volume Calculator

How do I calculate my pool’s volume in gallons?
To calculate pool volume in gallons, multiply length x width x average depth (all in feet) to get cubic feet, then multiply by 7.48 (gallons per cubic foot). For a rectangular pool, that’s straightforward; for round pools use diameter x diameter x average depth x 5.9, and for oval pools length x width x average depth x 6.7. For example, a 32 x 16 ft pool averaging 5 ft deep holds about 19,000 gallons. Our Pool Volume Calculator supports rectangular, round, and oval shapes.

How do I find the average depth of my pool?
To find average depth, add the shallow-end depth and the deep-end depth and divide by two; for a pool that’s 3 feet at the shallow end and 8 feet at the deep end, the average depth is 5.5 feet. This works for pools with a constant slope. For pools with a flat section then a sudden drop, you may need to calculate sections separately and add them. Average depth, not maximum depth, is what you use in the volume formula.

Why do I need to know my pool’s volume?
You need your pool’s volume to dose chemicals correctly—chlorine, pH adjusters, algaecide, and shock are all measured per a certain number of gallons, so an inaccurate volume leads to over- or under-treating. Volume also determines the right pump and filter size, heater capacity, and how long it takes to fill or turn over the water. Getting the gallon count right is the foundation of safe, balanced water, which is why it’s the first number every pool owner should establish.

How do I calculate volume for an irregular or freeform pool?
For an irregular or freeform pool, break it into simpler shapes—rectangles, circles, and triangles—calculate each section’s volume, and add them together. Alternatively, estimate an average length and average width and treat it as a rough rectangle or oval, accepting some approximation. Kidney and L-shaped pools are often split into two parts. The more irregular the shape, the more you should round up slightly so you don’t under-dose chemicals. A calculator helps combine the sections.

How many gallons is a typical swimming pool?
A typical residential in-ground pool holds roughly 15,000 to 30,000 gallons, with a common 16 x 32 ft pool around 19,000 gallons at average depth. Smaller above-ground pools may hold 5,000 to 12,000 gallons, while large or deep pools exceed 30,000. The exact figure depends on your pool’s dimensions and average depth, so always calculate your specific pool rather than relying on an average—chemical dosing and equipment sizing both depend on the real number.