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How To Calculate Pool Volume

Like a novice cook who needs to know how much of each ingredient to add to a dish, pool owners need to know how much of their maintenance products they need to add to their water. In order to do this properly, pool owners must know their pool volume — how much water is actually in their pool.

Calculating your pool volume is essential to correctly balancing the water. Making only rough estimates can result in errors and end up causing issues. Over-estimating is a waste of money; under-estimating will result in unsanitary water. If the volume of your pool isn’t in the original documentation, it’s easy to calculate it yourself.

Running The Numbers

Three average measurements are used to calculate pool volume: length, width, and depth. There are more complicated formulas for measuring oddly-shaped pools, but we’ll focus on the traditional pools.

First, carefully record the measurements mentioned above. Second, take each number and multiply them together. Finally, multiply that result by 7.5 (which is approximately how many gallons are in a cubic foot).

The combined formula should look like this:

Length × Width × Depth × 7.5 = Pool Volume (in Gallons)

Once you have this number, you should be able to apply the correct amount of pool chemicals to your pool water and avoid any future dosage issues.

Quick Reference

For your convenience, you can also consult the following charts. They detail the volume of many popular pool sizes.

Above Ground Pool Volume (48″ Wall Height)

Pool SizeGallons
15′ Round5,300
18′ Round7,600
20′ Round9,400
24′ Round13,600
27′ Round17,200
28′ Round18,500
11×25 Oval6,500
11×30 Oval7,800
15×25 Oval8,900
15×30 Oval10,600
18×33 Oval14,000
18×38 Oval16,100

Above Ground Pool Volume (52″ Wall Height)

Pool SizeGallons
15′ Round5,800
18′ Round8,300
20′ Round10,200
24′ Round15,300
27′ Round18,600
28′ Round20,000
11×25 Oval7,000
11×30 Oval8,400
15×25 Oval9,600
15×30 Oval11,500
18×33 Oval15,200
18×38 Oval17,500

In-Ground Pool Volume (Standard Depth)

Pool SizeGallons
12×24 Rectangle10,800
16×32 Rectangle19,200
16×36 Rectangle21,600
18×36 Rectangle24,300
20×40 Rectangle30,000
16×32 Oval17,200
18×36 Oval21,700
18×36 Oval21,700
20×40 Oval26,800
17×33 Grecian19,700
17×37 Grecian22,200
20×36 Grecian24,300
20×44 Grecian30,300
16×30 Kidney14,900
16×34 Kidney16,500
20×38 Kidney20,200

For more information on pool size or chemical usage, check our complete blog library, reach out to one of our knowledgeable staff members at your local Leslie’s store, or call 1-800-LESLIES. At Leslie’s, your pool is our passion.