Pool Volume Calculator
Type in your pool shape and dimensions to get the volume in gallons and liters, the number you need before adding any chemical.
| Shape | Formula | Example gallons |
|---|---|---|
| Rectangular | L x W x depth x 7.48 | 10771 |
| Round | 3.14 x radius squared x depth x 7.48 | 16919 |
| Oval | L x W x depth x 5.9 | 8496 |
Why pool volume matters
Almost every pool chemical is dosed by volume. Shock, chlorine, acid, algaecide, and stabilizer all list an amount per 10,000 gallons, so a wrong number throws off every dose that follows. The same figure also tells you how much water a pump has to move and how big a heater or filter should be. Get the gallons right once and the rest of the math gets easier.
Pick the right shape formula
A rectangle is length times width times average depth. A round pool uses the diameter, so a 24 foot round pool has a 12 foot radius, not a 24 foot length. An oval sits between the two and holds a little less than a rectangle of the same footprint, which is why it uses a smaller multiplier. When your pool is a mix of shapes, break it into a rectangle plus a circle and add the two volumes.
Measure average depth, not just the deep end
A pool with a 3 foot shallow end and an 8 foot deep end is 5.5 feet on average, not 8 feet. Guessing deep changes the result by thousands of gallons on a large pool. Measure the water depth at the shallow end, at the deep end, and in the middle, then average the three numbers for the closest estimate.
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Questions about this calculator
How many gallons is my pool?
Multiply length by width by average depth, then multiply by 7.48 for a rectangle. A 24 by 12 foot pool at 5 feet deep holds about 10,770 gallons. Use the diameter for a round pool and the smaller 5.9 multiplier for an oval.
How do I find the average depth?
Measure the water depth at the shallow end and the deep end, add them together, then divide by two. For a pool with a slope, also measure the middle and average all three numbers. That keeps a deep pool from inflating the gallon count.
How many gallons is a 24 foot round pool?
A 24 foot round pool that is 5 feet deep holds roughly 16,900 gallons. The radius is 12 feet, so the math is 3.14 times 12 squared times 5 times 7.48. Enter 24 in the length field and pick Round to check your own depth.
How many gallons does an oval pool hold?
An oval pool holds a bit less than a rectangle with the same length and width. A 24 by 12 foot oval at 5 feet deep holds about 8,500 gallons, while the matching rectangle holds about 10,770. Oval pools use the shorter 5.9 multiplier.
Does pool shape really change the volume?
Yes. A round pool loses the corners of its bounding square, and an oval loses water along its curved sides. A 24 by 12 foot oval holds about 20 percent less than the same rectangle, which is enough to change how much chlorine or acid you add.
Why do I need to know my pool volume?
Chemical labels, pump sizing, and heater sizing all key off gallons. If you think a 15,000 gallon pool is really 20,000 gallons, every dose runs light and the water drifts. The volume also tells you roughly how long the pump needs to filter the whole pool once.
How much water does a 16 by 32 foot pool hold?
A 16 by 32 foot rectangular pool at 5 feet deep holds about 19,150 gallons. At 6 feet deep it holds about 22,980 gallons. Change the length, width, and depth fields to match your pool and the calculator updates the gallons and liters.