Pool Volume Calculator
Knowing your pool’s volume in gallons is the single most useful number in pool care: every chemical dose depends on it. Enter your pool’s shape and dimensions below to get an instant, accurate estimate.
Pool Volume Calculator
Why use the Pool Volume Calculator
You can’t dose chlorine, salt or shock correctly without knowing your gallons. Guess and you’ll either waste money on chemicals or under-treat and watch the water turn green. This gives you the one number every other pool task depends on.
How to get your numbers
- Length & width: measure the water surface in feet, not the deck.
- Depths: read the shallow and deep ends off the pool wall or a weighted tape.
- Odd shapes: split the pool into rectangles or circles, calculate each, and add them.
Recommended for this job
How to use it
- Choose your pool shape.
- Enter the surface dimensions in feet.
- Enter the shallow and deep depths — the tool averages them for you.
Frequently asked questions
How do I calculate pool volume?
Multiply length × width × average depth, then multiply by 7.5 for a rectangular pool (there are 7.48 gallons in a cubic foot). Round pools use a 5.9 multiplier and ovals use 6.7.
What is the average depth of a pool?
Add the shallow-end depth and the deep-end depth and divide by two. For a constant-depth above-ground pool, the average is simply that one depth.
How many gallons is my pool?
It depends entirely on your dimensions — a typical 16×32 ft in-ground pool holds roughly 20,000–25,000 gallons. Enter your own measurements above for an exact figure.
Why do I need to know my pool’s volume?
Chlorine, salt, shock, algaecide and pH chemicals are all dosed per gallon of water. Guessing the volume means guessing the dose, which wastes chemicals or leaves the pool unsafe.
How do I calculate the volume of an irregular pool?
Break the shape into rectangles and circles, calculate each section separately, and add the results together for the total gallons.
How many gallons are in a cubic foot of water?
About 7.48 gallons. That is where the 7.5 multiplier for rectangular pools comes from.
Does this work for above-ground pools?
Yes. Choose round or oval and enter the diameter and wall height — above-ground pools usually have one uniform depth, so use it for both the shallow and deep fields.
How do I convert pool gallons to liters?
Multiply gallons by 3.785. The calculator shows both figures automatically.
