Pool Volume Calculator
Enter your pool's shape and dimensions below to get its volume in gallons (or liters) — the number every other chemical calculator on this site needs.
Estimated volume
Safety first
- Never mix chemicals together.
- Always add the chemical to the water — never water to the chemical.
- Wear gloves and eye protection when handling pool/spa chemicals.
- Keep chemicals out of reach of children and pets.
- Always follow the product label — it overrides any guidance here.
How it's calculated
Take your shallow and deep end depths, average them out, and multiply by the surface area and a conversion factor that matches your pool's shape (rectangular, round, oval, or kidney-shaped). Kidney shapes are the trickiest — their curves vary so much from pool to pool that this is really just a ballpark. If you have the exact volume from your pool builder, use that instead.
Example
A rectangular pool 32 ft long and 16 ft wide, with a shallow end of 3.5 ft and a deep end of 8 ft, has an average depth of 5.75 ft. That works out to about 22,000 gallons.
Frequently asked questions
How accurate is this pool volume calculator?
For rectangular and round pools with a consistent slope, it is accurate within a few percent. Irregular shapes (kidney, freeform) are rougher approximations — if you have the volume from your pool builder or manual, use that instead.
What depth should I use for an above-ground pool?
Use the height of the water, not the height of the pool wall. Most above-ground pools sit a few inches below the top of the wall — we default to 6 inches less, but you can edit it.
My pool has a shallow end and a deep end — which depth do I enter?
Enter both. We average them to estimate the overall water volume, which works well for pools with a consistent, gradual slope.
Does this work for hot tubs and spas?
Yes — use the Hot Tub Volume calculator instead, which lets you enter gallons directly from your manual or estimate by seat count.
Why do I need to know my pool volume at all?
Almost every chemical dose (chlorine, salt, pH, alkalinity) is calculated per gallon of water. Getting the volume right is the foundation for every other calculator on this site.