Pool gallons by size

Every chemical dose is multiplied by your gallons, so a wrong volume makes every dose wrong by the same percentage. The table gives two quick values per size. Each size page adds every wall height or depth, the manufacturer capacities we could confirm, and starting doses.

Pool sizes at a glance

Size	Round and oval: 48 in wall · rectangle: 5 ft avg	Round and oval: 52 in wall · rectangle: 5.5 ft avg
8 ft round	1,354 gal	1,466 gal
9 ft round	1,713 gal	1,856 gal
10 ft round	2,115 gal	2,291 gal
12 ft round	3,046 gal	3,300 gal
14 ft round	4,146 gal	4,491 gal
15 ft round	4,759 gal	5,155 gal
16 ft round	5,415 gal	5,866 gal
18 ft round	6,853 gal	7,424 gal
20 ft round	8,460 gal	9,165 gal
21 ft round	9,327 gal	10,105 gal
22 ft round	10,237 gal	11,090 gal
24 ft round	12,183 gal	13,198 gal
27 ft round	15,419 gal	16,704 gal
28 ft round	16,582 gal	17,964 gal
30 ft round	19,036 gal	20,622 gal
12 × 24 ft oval	6,924 gal	7,501 gal
15 × 30 ft oval	10,818 gal	11,720 gal
16 × 32 ft rectangle	19,150 gal	21,065 gal
18 × 33 ft oval	14,124 gal	15,301 gal
20 × 40 ft rectangle	29,922 gal	32,914 gal

Above-ground values are geometry at 90% fill, before the real-capacity correction. Open a size for models and doses.

Round pools

Volume grows with the square of the diameter: a 24 ft pool holds four times the water of a 12 ft pool with the same wall. Real pools also hold less than the math for the size on the box. Across 26 manufacturer capacities we checked, the median was 0.93 of the math, lower for inflatable-ring pools. Pick your diameter: 8 ft, 9 ft, 10 ft, 12 ft, 14 ft, 15 ft, 16 ft, 18 ft, 20 ft, 21 ft, 22 ft, 24 ft, 27 ft, 28 ft, or 30 ft. Other diameters are rows in the table above.

Oval pools

Most above-ground ovals are a rectangle with a half circle on each end. Measuring one with an ellipse formula undercounts by about 12%. Sizes: 12 × 24, 15 × 30, and 18 × 33. For other ovals, use the oval pool volume calculator.

Rectangular pools

For a rectangle, only depth is uncertain. For a steady slope, average the shallow and deep ends. If the deep end is a separate section, weight each depth by its length; otherwise, you can overstate the volume by 10% or more. Sizes: 16 × 32 and 20 × 40, plus rectangular frame pools on the 12 × 24 and 16 × 32 pages.

Average pool sizes

There is no official average, and we won't invent one. For scale, an Olympic pool is on its own page: how many gallons in an Olympic pool. What we can show: among inground sizes, 16 × 32 is one of the most searched, and it holds 15,320–22,023 gallons, depending on depth. Above ground, round pools of 15–24 ft with 48–54 in walls hold roughly 4,400–12,700 gallons in rated or estimated capacity. Brand capacities are collected in the above-ground pool gallons chart, and Coleman frame pools on Coleman Power Steel pool gallons.

Your size isn't listed?

The pool volume calculator handles rectangle, round, oval, kidney, and L-shaped pools, in feet or meters. For above-ground pools, choose "Above-ground wall height" and your pool type. The most accurate method needs no tape measure: add a known weight of salt or stabilizer and measure the rise a day later.

FAQ

How many gallons in a pool average?

There is no single average. Round above-ground pools of 15–24 ft with 48–54 in walls hold about 4,400–12,700 gallons. A 16 × 32 inground pool holds 15,320–22,023 gallons, depending on depth. Measure yours for any dosing.

How many gallons in an average inground pool?

We found no official figure. Two sizes people often search for: 16 × 32 ft holds about 18,200 gallons, and 20 × 40 ft holds about 28,400 gallons, at 3.5–6 ft deep.

Sources

• Manufacturer capacities (Intex, Bestway), read 2026-09-29: see the above-ground pool gallons chart
• Volume formulas and correction factors: methodology