Pool Volume Calculator
Calculate pool gallons and liters from length, width, and average depth
Enter the pool shape and the average water depth. The result is cubic feet, US gallons, and liters. It does not tell you how much chlorine or acid to add. Read the product label for a dose per gallon.
Calculator Inputs
For a slope, use the shallow end and the deep end added together, then divided by 2.
Results
Enter values above to see your results
How to use this calculator
- Choose rectangle, oval, or round.
- Enter the surface size in feet and the average depth in feet.
- If the bottom slopes, average the shallow and deep depths before you enter depth.
How the calculation works
A rectangle is length × width × average depth. An oval is treated as an ellipse, so the area is π ÷ 4 × length × width, then times depth. A round pool is π × radius² × depth.
US gallons are cubic feet × 1,728 ÷ 231, which is 7.48052 gallons per cubic foot. Liters are gallons × 3.78541.
Average depth
A pool that is 3 feet at one end and 7 feet at the other has an average depth of 5 feet if the slope is even. Use that average. Do not use only the deep end, or the gallon count will be high.
Worked example
20 ft × 10 ft rectangle, 4 ft average depth
20 × 10 × 4= 800 cubic feet800 × (1,728 ÷ 231)= 5,984 gallons5,984.42 × 3.78541= 22,653 litersTips & Best Practices
- •Measure the water, not the coping, if you want the volume you actually fill.
- •Round and oval results use π, so the last gallon can move by one when you round.
Frequently Asked Questions
How many gallons are in a pool?
Multiply length, width, and average depth in feet, then multiply by 7.48052. A 20 by 10 foot pool at 4 feet deep holds 5,984 US gallons.
How do I handle a sloped bottom?
Add the shallow depth and the deep depth, divide by 2, and use that as the average depth. That matches an even slope.
Does this include chemical doses?
No. Gallons are the input a product label asks for. The dose per gallon is on the label, and this page does not replace it.
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