Pool volume formulas
Average depth = (Shallow + Deep) ÷ 2
Rectangle: L × W × Avg depth × 7.48
Round: π × (D ÷ 2)² × Avg depth × 7.48
Oval: π × (L ÷ 2) × (W ÷ 2) × Avg depth × 7.48
Rectangle: L × W × Avg depth × 7.48
Round: π × (D ÷ 2)² × Avg depth × 7.48
Oval: π × (L ÷ 2) × (W ÷ 2) × Avg depth × 7.48
Example: A 32 × 16 ft rectangular pool, 3.5 ft at the shallow end and 8 ft at the deep end, averages 5.75 ft. It holds 2,944 cubic feet — 22,023 gallons (83,365 liters). At 10 gallons a minute it takes about 36.7 hours to fill.
Notes
- For pools with a steep hopper, the average-depth method slightly overestimates volume.
- One cubic foot holds 7.48 U.S. gallons; one cubic meter holds 1,000 liters.
Heating costs matter too — compare running costs with the electricity cost calculator.
Frequently asked questions
How do I calculate pool volume in gallons?
Length × width × average depth × 7.48 for a rectangular pool. A 32 × 16 ft pool from 3.5 to 8 ft deep averages 5.75 ft: 32 × 16 × 5.75 × 7.48 ≈ 22,023 gallons.
How do I calculate a round pool?
π × radius² × average depth × 7.48. A 24-ft round pool 4 ft deep holds about 13,500 gallons.
Why do I need to know my pool volume?
Chemical doses are given per 10,000 gallons. The wrong volume means over- or under-dosing chlorine, shock, salt or algaecide.
How long does it take to fill a pool?
Volume ÷ flow rate. A garden hose delivers about 5–10 gallons a minute, so a 22,000-gallon pool takes 37–73 hours.