Above Ground Pool Volume by Size

Water depth, not wall height

Above ground pools are sold by wall height: 48 inch, 52 inch, 54 inch. But the water never reaches the top rail. Skimmer operation and splashing need 6 to 8 inches of freeboard, so a 52 inch wall (4 feet 4 inches) holds about 4 feet of water, and a 48 inch wall holds about 3.5 feet. Using the wall height overstates the volume by 10 to 15 percent.

Round and oval above ground pools have essentially flat bottoms, so there is no shallow end and deep end to average. Measure the water depth directly, or subtract 7 inches from the wall height as a rule of thumb.

The cylinder formula, worked out

A round above ground pool is a cylinder. Volume in gallons = 3.1416 x radius x radius x water depth (feet) x 7.48. The radius is half the diameter: a 24 foot pool has a 12 foot radius.

Example: 24 foot round, 52 inch wall, 4 feet of water. Radius = 12. Cubic feet: 3.1416 x 12 x 12 x 4 = 1,809.6. Gallons: 1,809.6 x 7.48 = 13,536 gallons. The quick diameter formula gives the same answer within a fraction of a percent: 24 x 24 x 4 x 5.9 = 13,594 gallons.

Example: 18 foot round, 48 inch wall, 4 feet of water. Radius = 9. Cubic feet: 3.1416 x 9 x 9 x 4 = 1,017.9. Gallons: 1,017.9 x 7.48 = 7,614 gallons. So an 18 foot by 4 foot pool holds about 7,600 gallons.

Round above ground pool gallons chart

Pool diameter	Common wall height	Water depth used	Gallons
12 ft	48 in	3.5 ft	2,961
15 ft	48 in	3.5 ft	4,627
18 ft	48-52 in	3.5 ft	6,662
21 ft	52 in	4 ft	10,364
24 ft	52 in	4 ft	13,536
27 ft	52 in	4 ft	17,132
28 ft	52 in	4 ft	18,425
30 ft	54 in	4.25 ft	22,473

Oval above ground pools

Oval pools use length x width x water depth x 6.7. A 12 by 24 foot oval with 4 feet of water holds 12 x 24 x 4 x 6.7 = 7,718 gallons. A 15 by 30 foot oval with 4 feet of water holds 15 x 30 x 4 x 6.7 = 12,060 gallons. That answers the common question directly: a 15 by 30 above ground pool holds about 12,000 gallons.

Ovals are popular because they fit narrow yards while giving a longer swim lane than a round pool of similar width. For the full oval treatment, see oval pool volume.

Soft-sided and frame pools (Intex, Bestway, Coleman)

Soft-sided pools follow the same math, but the stated dimensions are the outside of the frame. The water surface is an inch or two smaller in each direction, which trims a few percent off the chart numbers above. Manufacturers print an estimated gallon capacity on the box; it usually assumes the pool is filled to about 90 percent of wall height, which lines up with the water-depth rule in this guide. If the box number and your calculation disagree by more than 10 percent, trust your measurement of the actual water depth.

Liters for a 24 foot pool

For readers outside the US: 13,536 gallons x 3.78541 = about 51,239 liters. That is the answer to how many litres of water are in a 24 foot above ground pool: roughly 51,000 liters at 4 feet of water depth.

Get your exact number: the free pool volume calculator runs the round and oval formulas with your own diameter and water depth.