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Free tool

Pool Volume Calculator

Pick your pool's shape, enter the dimensions, and get an instant gallons estimate for chemicals, pump and heater sizing.

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For a constant-depth pool, enter the same number in both boxes.

Approximate volume
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This is a close estimate. Freeform and kidney shapes vary, so use your average length and width. Need an exact number or help with your equipment? We are happy to take a look.

Call (817) 793-2977
Why it helps

What your pool volume is good for

Chemical dosing

Chlorine, shock and salt are all dosed by the gallon. The right volume keeps your water balanced and safe to swim.

Pump & filter sizing

Your gallons set the turnover rate, which decides the right pump and filter so the water actually circulates and cleans.

Heater & salt systems

Heaters and salt chlorinators are matched to volume. Too small and they struggle, too big and you overpay.

Calculator questions

Pool volume FAQs

How do I calculate my pool's volume in gallons?

Multiply the surface area by the average depth, then by 7.48 gallons per cubic foot. For a rectangular pool that is length times width times average depth times 7.48. A kidney or freeform pool is close to that using about nine tenths of its length and width. Average depth is the shallow end plus the deep end divided by two. The calculator above does the math for you.

Why does knowing my pool volume matter?

Your gallons determine how much chlorine, shock, salt and other chemicals to add, and it is the starting point for sizing a pump, filter or heater. Getting it right keeps your water balanced and your equipment matched to the pool.

Is this accurate for kidney or freeform pools?

It gives a close estimate. For an irregular or freeform pool, use the average length and average width and the result will be in the right range. For an exact figure, call us at (817) 793-2977.

How many gallons is an average backyard pool?

Most residential in-ground pools hold somewhere between 15,000 and 30,000 gallons, but it varies a lot with size and depth. Use the calculator with your own measurements for your pool's number.

Got your number? Let's keep your pool running right

Whether it is balancing chemicals, sizing a new pump or heater, or fixing what is broken, McEwan Pools has it covered. Owner-operated by a licensed electrician with 25+ years of experience.

Call (817) 793-2977