Pool Volume Calculator
Enter your pool shape and dimensions to get the volume in gallons and liters. It handles rectangle, round, oval, and freeform pools, with a sloped or constant bottom. Everything runs in your browser.
- US gallons
- 21,065
- Liters
- 79,740
- Cubic meters
- 79.7
- Cubic feet
- 2,816
Volume is the surface area times average depth, converted to gallons. A sloped bottom uses the average of the shallow and deep ends, which is exact for a steady slope and close enough for most pools. Freeform uses 85% of the bounding rectangle as an estimate, so measure the real surface area if you need precision.
Volume is the number everything else depends on
Pool chemistry is dosed per gallon. Chlorine, salt, cyanuric acid, alkalinity adjusters, and algaecide all assume you know how much water you are treating. Get the volume wrong and every dose after it is wrong too, which is the most common reason a pool will not hold a stable reading. Measure once, calculate, and write the number down.
Once you have your volume, the salt calculator turns it into an exact dose for a saltwater pool. More pool math is in the full calculator list.
Frequently asked questions
How do I calculate my pool's volume?
Multiply the surface area by the average depth, then convert to gallons. For a rectangular pool that is length times width times average depth times 7.48. This calculator does it for you and handles round, oval, and freeform shapes too.
What is the average depth if my pool has a deep end?
For a pool with a steady slope from shallow to deep, the average depth is simply the shallow depth plus the deep depth divided by two. Enter both ends above and the calculator uses that average.
How many gallons is a typical pool?
A common 32 by 16 foot inground pool with a sloped bottom holds roughly 17,000 gallons. A 24 foot round above ground pool about 4 feet deep holds roughly 13,500 gallons. Your exact number depends on your dimensions, so measure and calculate rather than guess.
Why do I need to know my pool volume?
Almost every pool chemical is dosed per gallon. If you do not know your volume, you cannot dose chlorine, salt, stabilizer, or algaecide correctly, and you will either waste product or fail to treat the water. Volume is the first number to nail down.
Is this calculator accurate for freeform pools?
It estimates a freeform pool as 85 percent of its bounding rectangle, which is close for many kidney and lagoon shapes. For an irregular pool where precision matters, measure the actual surface area and enter it as a rectangle with width 1 to feed the area directly.