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Pools & WaterRound Pool Calculator — How Many Gallons?
Enter your round pool’s diameter and average depth to get its volume in gallons — the number you need for salt, chlorine, and other chemical dosing.
How this calculator works
Volume = π × radius² × average depth (in feet), and each cubic foot holds about 7.48 gallons. A 24-ft round pool at 4 ft deep holds about 13,500 gallons.
What changes how much you need
- Radius is half the diameter — measure the water, not the outside of the wall or liner.
- Average depth = (shallow + deep) ÷ 2 if the bottom isn’t flat.
- For an oval pool, use the rectangular pool calculator and multiply by about 0.89.
- Knowing exact gallons keeps salt and chlorine dosing safe — products dose per 10,000 gallons.
Frequently asked questions
How many gallons is a 24-ft round pool?
About 13,500 gallons at 4 ft average depth. Volume = π × radius² × depth × 7.48.
How do I calculate round pool gallons?
Multiply π × radius² × average depth (feet) × 7.48. Enter the diameter and depth above and it does it for you.
What about an oval pool?
Estimate it as a rectangle (length × width × depth × 7.48) and multiply by about 0.89.