Assuming normal shapes and depths, here’s a chart. Otherwise, take a guess, or ask our water lab technician to re-figure it during your next water test.

Round Metal Pools – Gallons

Size 48″ 52″ 54″
12′ 3,500 3,800 4,000
15′ 5,300 5,700 5,900
18′ 7,600 8,200 8,500
20′ 9,400 10,000 10,400
21′ 10,000 11,000 11,500
24′ 13,700 14,600 15,000
27′ 15,900 16,800 17,400
28′ 18,500 20,500 21,500
30′ 19,000 21,000 22,000
33′ 25,000 27,500 28,500

 

Round Blow-up Pools – Gallons

Diameter Height Gallons
8′ 30″ 640
10′ 30″ 1000
12′ 30″ 1500
12′ 36″ 1800
15′ 36″ 2800
15′ 42″ 3300
15′ 48″ 3750
18′ 42″ 4800
18′ 48″ 5500
18′ 52″ 6000

 

Oval Pools – Gallons

Size 48″ 52″ 54″
11’ x 18½’ 6,000 6,600 6,800
11’ x 25’ 8,500 9,200 9,500
12’ x 17’ 6,000 6,600 6,800
12’ x 24’ 8,500 9,500 9,800
15’ x 25’ 9,500 10,000 10,600
15’ x 26’ 10,200 11,000 11,400
15’ x 30’ 13,700 14,800 15,400
18’ x 33’ 17,500 18,900 19,600
18’ x 38’ 19,500 21,000 22,000
18’ x 40’ 20,500 22,000 22,900

 

Rectangular Inground Pools – Gallons

Size 48″ Shallow to 96″ Deep end
12’ x 24’ 10,000
16’ x 32’ 20,000
18’ x 36’ 25,000
20’ x 40’ 30,000
24’ x 44’ 45,000
25’ x 50’ 50,000

 

To calculate other sizes and shapes; all measurements are in feet:

Round: Diameter x diameter x average depth x 5.9
or
Round: Radius x radius x average depth x 23.6
Rectangle: Length x width x average depth x 7.5
Oval: Length x width x average depth x 6.6
Free Form: Surface area (square feet) x average depth x 7.5
Blow-up Pools: Contact the manufacturer since the walls are not vertical and the collars affect depth, there is no formula