Free tool

Pool Volume Calculator (Gallons and Liters)

Enter your shape and depths to get your pool's gallons, then dose chlorine, pH and salt from that number.

How these numbers are worked out, and the sources behind them: see our methodology. Updated 2026-10-21.

Pool volume formulas by shape

All dimensions are in feet. One cubic foot holds 7.48 gallons, which is where the multipliers come from.

Rectangle or square

length x width x average depth x 7.5

Example: 16 x 32 x 5 x 7.5 = 19,200 gal

Round

diameter x diameter x average depth x 5.9

Example: 24 x 24 x 4 x 5.9 = 13,600 gal

Oval

length x width x average depth x 6.7

Example: 15 x 30 x 4 x 6.7 = 12,100 gal

Kidney

0.45 x (A + B) x length x average depth x 7.48

Example: 0.45 x (10 + 14) x 32 x 5 x 7.48 = 12,900 gal

L-shape

(length x width + length2 x width2) x average depth x 7.5

Example: (16 x 32 + 10 x 8) x 5 x 7.5 = 22,200 gal

Grecian (cut corners)

(length x width - 2 x corner²) x average depth x 7.5

Example: (16 x 32 - 2 x 9) x 5 x 7.5 = 18,500 gal

How many gallons is my pool?

Inground rectangle pools
Size	4.5 ft average	5.5 ft average
12 x 24 ft	9,700 gal	11,900 gal
14 x 28 ft	13,200 gal	16,200 gal
15 x 30 ft	15,200 gal	18,600 gal
16 x 32 ft	17,300 gal	21,100 gal
18 x 36 ft	21,900 gal	26,700 gal
20 x 40 ft	27,000 gal	33,000 gal

Round above-ground (52 in wall)
Diameter	Gallons
12 ft	3,300
15 ft	5,100
18 ft	7,300
21 ft	10,000
24 ft	13,000
27 ft	16,500
30 ft	20,400
33 ft	24,600

Oval above-ground (52 in wall)
Size	Gallons
12 x 24 ft	7,400
15 x 30 ft	11,600
16 x 32 ft	13,100
18 x 33 ft	15,300
18 x 40 ft	18,500

How to measure your pool

Measure the water, not the walls. Depth runs from the water surface to the floor, not from the coping.
For above-ground pools, water usually sits about 6 inches below the top of the wall.
Use a long tape or a pole with a weighted line. Take the deep-end reading at the deepest point.
Steps, benches and swim-outs hold less water than their footprint suggests; the estimate already rounds for that.
Tanning ledges (baja shelves) are only 6 to 12 inches deep. Measure them as their own L-shape section with a shallow depth.

How accurate is it, and how to check

Shape formulas land within about 10 to 15% for most pools. To find your true volume, add a known amount of salt or stabilizer, wait for it to mix, and see how far the reading moves. For example, if 50 lb of salt raised a pool by 400 ppm, it holds about 50 x 1,000,000 / (8.34 x 400) = 15,000 gallons. The salt calculator and stabilizer calculator show the dose-per-gallon figures to work backward from.

How to use this calculator

1
Pick your pool's shape
Rectangle, round, oval, kidney, L-shape, Grecian or above-ground. Each uses its own formula.
2
Measure the water, not the walls
Measure length and width at the waterline, and depth from the water surface to the floor.
3
Enter depths
Use one average depth, a shallow and deep end, or a sloped hopper with a flat shallow section.
4
Read gallons, liters and cubic feet
Add an attached spa if you have one. Fill time, fill cost and pump turnover appear below.
5
Dose from that number
Tap a dose button to open the chlorine, pH, salt or other calculators with your gallons filled in.

More free tools

Pool Chlorine Calculator

Use your gallons to dial in the exact chlorine dose.

Pool pH Calculator

Raise or lower pH with acid, soda ash or borax.

Pool Salt Calculator

Saltwater pool? How much salt to add.

Pool Chemical Calculator

Every dose from one test.

Pool Cost of Ownership Calculator

What your gallons cost to run each year.

Which Calculator Do I Need?

Two questions to the right tool.

More pool calculators →

Frequently asked

Questions about pool volume

How many gallons in a 16x32 pool?

About 19,200 gallons at a 5 ft average depth (16 x 32 x 5 x 7.5). At 4.5 ft it is about 17,300 gallons, and at 5.5 ft about 21,100.

How many gallons in a 24 ft round above-ground pool?

About 13,000 gallons with a 52 inch wall filled to about 46 inches (24 x 24 x 3.83 x 5.9). With a 48 inch wall it is about 11,900, and with a 54 inch wall about 13,600.

How do I calculate a kidney pool's volume?

Measure the width across the narrow lobe (A), the wide lobe (B) and the length end to end. Gallons = 0.45 x (A + B) x length x average depth x 7.48. A 32 ft kidney with widths of 10 and 14 ft at 5 ft average holds about 12,900 gallons.

How do I convert liters to gallons?

Divide liters by 3.785 to get US gallons, or multiply gallons by 3.785 to get liters. One cubic meter is 1,000 liters, about 264 gallons. One cubic foot holds 7.48 gallons.

How long does it take to fill a pool?

A garden hose runs about 9 gallons a minute, so roughly 540 gallons an hour. A 15,000 gallon pool takes about 28 hours. Two hoses halve it; a water truck takes an hour or two.

Does the volume change with the water level?

Yes. Every inch of water in a 16x32 pool is about 320 gallons. If you run the level low or high, measure depth from the actual water line.

How accurate is this pool volume estimate?

Within about 10 to 15% for most pools. Steps, benches, tanning ledges and curved walls make it less exact. To check the real number, add a known amount of salt or stabilizer and see how far the reading moves.

What if my pool has a shallow end and a deep end?

Choose Shallow + deep and enter both. If the shallow end stays flat for a while before sloping, use Sloped hopper and enter the length of the flat section for a more accurate average.

Why do I need to know my pool's volume?

Every chemical dose (chlorine, pH, alkalinity, calcium, stabilizer, salt) starts from your pool's gallons. Get this number once, then reuse it in the other calculators or save it in the Skimmer app.