How to Calculate Pool Volume
Knowing your pool's volume in gallons or liters is essential for dosing chemicals, sizing pumps and heaters, and estimating refill costs. The formula depends on the shape; most residential pools are rectangular, round, oval, or kidney-shaped.
Rectangular Pools
For a rectangular pool, multiply length, width, and average depth. Then convert cubic feet to gallons by multiplying by 7.48:
For a sloped bottom, average depth is (shallow + deep) / 2. A 16 x 32 ft pool with a 3 ft shallow end and 8 ft deep end has an average depth of 5.5 ft, for 16 x 32 x 5.5 x 7.48 = 21,073 gal.
Round Pools
Circular above-ground pools are consistent depth, so the formula is simpler:
Oval and Kidney Pools
Oval pools: treat as a rectangle, then multiply by 0.89 to approximate the rounded ends. Kidney pools are irregular - the standard method is length x width x average depth x 0.45 x 7.48.
Volume by Shape (Quick Reference)
| Typical Size | Shape | Volume (gal) | Liters |
|---|---|---|---|
| 15 ft round, 48" | Round above-ground | 5,280 | 19,987 |
| 24 ft round, 52" | Round above-ground | 14,715 | 55,700 |
| 12 x 24 ft, 5 ft | Rectangular | 10,771 | 40,773 |
| 16 x 32 ft, 5.5 ft avg | Rectangular in-ground | 21,073 | 79,772 |
| 15 x 30 ft, 5 ft | Oval above-ground | 14,988 | 56,735 |
Why Volume Matters for Chemicals
- Chlorine shock - 1 lb per 10,000 gallons for a 10 ppm shock
- Liquid chlorine (12.5%) - 10 fl oz per 10,000 gallons adds 1 ppm
- Muriatic acid - 1 qt per 10,000 gallons lowers pH by about 0.2
- Stabilizer (CYA) - 13 oz per 10,000 gallons to reach 30 ppm