Lawn & Garden

Pool Volume Calculator: How Many Gallons are in Your Pool?

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25 June, 2024 • Updated 24 days ago
There are various reasons swimming pool owners may need a Pool Volume Calculator for their pool, such as upgrading pool components, adding the right amount of chlorine or installing an adequate pool heater.

This article will help you quickly and accurately calculate your pool volume in gallons, while also providing conversion tools to get your results in a measurement that is familiar to you. 

So don’t overwhelm yourself with numbers, simply measure the width, length, and depth of your pool and return to this article to acquire your pool volume in no time.

Determining Your Pool’s Average Depth 

The first step to calculating your swimming pool volume is determining the average depth, as this is the number that will replace the “depth” placeholder in the formulas. If you have a completely level pool floor, this will be as simple as measuring from pool rim to the pool bottom, but most pools have varied depths.

Start by measuring the shallowest point of your pool as well as the deepest point of your pool, then insert your values into this formula:

shallow end depth(ft.) + deep end depth(ft.) / 2 = average pool depth(ft.)

After completing this formula, you now have the average depth you will insert in the following formulas.

Pool Volume Calculator

Rectangular Pool Volume

The formula used to calculate the volume of your rectangular swimming pool requires your pool length, width, and the average depth you have already calculated.

The formula below is used to not only calculate the volume of your pool, but also to convert your results from cubic foot into gallons. The normal formula for volume is multiplied by 7.5, as one cubic foot is equal to 7.5 gallons, thus converting your result into a more commonly used unit of measurement. This means that the 7.5 can be removed from the equation to get the answer in cubic feet.

Length × width × depth × 7.5 = volume (gallons)

Circular Pool Volume

Similar to the rectangular pool, we use the basic volume formula of a circle and multiply it by the mathematical constant, 7.5, to determine the volume of a circular swimming pool in gallons.

For this formula, you will need the pool dimensions for the average depth of your pool, as well as the radius (diameter × 1/2) of your pool.

3.14 (π) × radius2 × depth × 7.5 = volume (gallons)

Oval Pool Volume

Calculating the volume of an oval pool requires a combination of the rectangular and circular pool formulas,

You will need all the same measurements as you would for a rectangular pool, the length, width and average depth, as well as some numerical constants to factor in the rounded edges.

length × width × 3.14 (π) / 4 × depth × 7.5 = volume (gallons)

Irregular-Shaped Pool Volume

Determining the volume of an irregular pool shape, such as a kidney shape, is a bit more tricky, but still possible. 

For these types of pools, you will have to identify circles, squares and rectangles within the pool’s overall shape. The volume of these shapes will then have to be calculated and added together to produce the pool’s overall volume.

While this is certainly a bit more work, it still uses the same basic calculators and measurements required above, so your calculation should go down without a hitch.

Conversion Calculator

Below we have included a calculator to help you convert your measurements and results into the units you are most familiar with.

Pool Volume Reference Chart

We have compiled the measurements for the most common pool sizes below, using the average depths of the types of pools we incorporated.

In-ground Pool Reference Chart

We based the following measurements on the most common in-ground pool sizes, as well as the most common average in-ground pool depths.

Rectangle dimensions (ft.)Depth (ft.)Volume (gal)
10 × 2034 500
10 × 2046 000
10 × 2057 500
15 × 30310 125
15 × 30413 500
15 × 30516 875
20 × 40318 000
20 × 40424 000
20 × 40530 000

Above Ground Pool Reference Chart

The following dimensions are based on the most commonly available above ground pools on the market and the measurements they provide.

Circle dimensions (ft.)Depth (inch)Volume (gal)
12483 391
12523 671
15485 299
15525 736
18487 630
18528 260
214810 386
215211 242
244813 565
245214 684
274817 168
275218 584
304821 195
305222 944
Oval dimensions (ft.)Depth (inch)Volume (gal)
12 × 23486 486
12 × 23527 021
15 × 304810 575
15 × 305211 447
18 × 334813 958
18 × 335215 110
21 × 414820 233
21 × 415221 902


While many parts of pool ownership require a professional hand, determining the volume of your pool can be a completely independent task that costs you no more than a bit of time.

That being said, should your pool prove to be too irregularly shaped to properly calculate the volume of using the methods above, any professional pool installation and maintenance company should be able to provide you with the proper calculations after a pool inspection.

We hope this pool volume calculator has helped you determine pool’s total volume and feel confident in the results.

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