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Pool Volume Calculator

Volume of a above-ground pool

Calculate above-ground pool volume in gallons, or use our size chart for standard round and oval kits. Free.

✓ Sloped & deep-end floors ✓ Gallons, litres & m³ ✓ Combine irregular shapes

The formula

π × radius² × Water Depth × 7.48 = US gallons

Worked example

Above-ground pools are rarely filled to the rim. A 52-inch wall typically holds about 46–48 inches of water. Use the water depth for an accurate number.

This calculator uses the precise cubic-foot-to-gallon value (about 7.48 US gallons per cubic foot) for your above-ground pool and lets you switch between US gallons, imperial gallons, litres, and cubic metres.

Standard above-ground pool size chart

Approximate water capacity for standard above-ground kits, filled to about 48 inches of water in a 52-inch wall. Your exact figure depends on how high you fill the pool — use the calculator above for precision.

Round pools

SizeApprox. volume
12 ft round3,384 gal
15 ft round5,288 gal
18 ft round7,614 gal
21 ft round10,364 gal
24 ft round13,536 gal
27 ft round17,132 gal
30 ft round21,151 gal
33 ft round25,592 gal

Oval pools

SizeApprox. volume
12 × 24 ft oval6,768 gal
15 × 26 ft oval9,165 gal
15 × 30 ft oval10,575 gal
18 × 33 ft oval13,959 gal
Fill line matters

A 52-inch wall does not mean 52 inches of water. Most above-ground pools are filled to roughly the middle of the skimmer, about 46–48 inches. Filling to the full wall height overstates volume by 8–10%.

How to calculate above-ground pool volume step by step

You will need these measurements:

  1. Measure diameter and water depth. Measure the diameter (straight across the widest point) and the actual water depth in feet — round pools are usually filled below the rim.
  2. Find the radius and the surface area. Radius = diameter ÷ 2. Surface area = π × radius² (π ≈ 3.14159).
  3. Multiply by depth, then convert. Volume in cubic feet = surface area × depth. Multiply by 7.48 for US gallons.
Worked example

A 24 ft round pool filled to 4 ft: radius 12 ft, π × 12² × 4 = 1,810 cubic feet, then × 7.48 ≈ 13,536 US gallons.

Water depth vs wall height on round pools

The mistake that throws off round-pool volume most is using the wall height instead of the actual water depth. A round above-ground pool with a 52-inch wall is rarely filled to the top — water usually sits around 46–48 inches, below the skimmer cut-out. Always measure from the floor to the real waterline. Measure the diameter straight across the widest point through the center; measuring a chord that misses the center understates the diameter and, because area depends on the radius squared, even a small diameter error has an outsized effect on the result. Round pools are uniform depth, so there is no shallow-and-deep average to worry about — just one honest water depth.

Questions

Common answered

A 24 ft round pool holds about 13,500 gallons at 4 ft of water. Filled deeper or shallower changes it proportionally — enter your actual water depth above for your number.
Always the water depth. A 52-inch-wall pool typically holds only about 46–48 inches of water, since it's filled to just below the skimmer. Using the full wall height overstates the volume.
Measure straight across the widest point, passing through the center. A line that misses the center comes up short, and because volume depends on the radius squared, that error is magnified in the result.
The surface of a round pool is a circle, whose area is π × radius². Squaring the radius is what captures the circular area; multiplying by depth then gives the volume.
Yes — both use π × radius² × water depth. Above-ground pools just tend to be uniform depth and filled below the rim, so the water depth is the figure to measure.