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Pools & WaterPool Volume Calculator — How Many Gallons Is My Pool?
Enter your pool’s length, width, and average depth to get its volume in gallons — the number you need for dosing chemicals, sizing a heater, or buying a liner.
How this calculator works
Volume = length × width × average depth (in feet), and each cubic foot holds about 7.48 gallons. Average depth is roughly (shallow end + deep end) ÷ 2.
What changes how much you need
- Average depth = (shallow + deep) ÷ 2 for a pool that slopes between them.
- Oval pool? Multiply the result by about 0.89. Round pool? Use π × radius² × depth × 7.48.
- Knowing your exact gallons keeps chemical dosing safe — most products dose per 10,000 gallons.
- Measure the water dimensions, not the outside of the pool walls.
Frequently asked questions
How many gallons is my pool?
For a rectangular pool: length × width × average depth (ft) × 7.48. A 32×16 ft pool averaging 5 ft deep holds about 19,150 gallons.
What is "average depth"?
If your pool slopes from a shallow to a deep end, average depth is the two added together and divided by two.
How do I handle an oval or round pool?
For an oval, multiply the rectangular result by ~0.89. For a round pool, use π × radius² × depth × 7.48.