Use this free pool gallons calculator to plan a home-improvement or DIY project from the measurements and product information you already have.
HomeCalc shows the formula behind the result and keeps product-dependent assumptions editable where possible, so the calculation can match the material, package or supplier you actually plan to use.
The calculator determines the pool's cubic-foot volume from its shape and average depth, then converts cubic feet to US gallons using approximately 7.48052 gallons per cubic foot.
QUICK POOL GALLONS ESTIMATOR
Pool Gallons Calculator: How Many Gallons Is My Pool?
Quickly estimate how many US gallons of water a pool holds from its dimensions and average depth.
Estimated result
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Find your pool capacity in US gallons
The calculator determines the pool's cubic-foot volume from its shape and average depth, then converts cubic feet to US gallons using approximately 7.48052 gallons per cubic foot.
cubic feet × 7.48052 = US gallons
What to check before using the result
- Measure the inside water dimensions rather than the outside structure.
- Use average depth when depth changes across the pool.
- Round, oval and rectangular pools use different area formulas.
- Manufacturer capacity is preferable when the pool has complex molded geometry.
Once the pool volume is known in cubic feet, gallons follow directly from the conversion factor. Most estimation error therefore comes from the pool dimensions and average depth rather than the gallon conversion itself.