Pool Volume Calculator

Real geometry — not pool-store rules of thumb. Get your gallons, then send them straight to the salt calculator.

Shape & dimensions

21,065
gallons
≈ 79,740 liters
176k
lbs of water
See the math

True geometry, not pool-store rules of thumb: gallons = surface area × average depth × 7.48052. Rectangle area = length × width = 512 sq ft. Average depth = (3 + 8) ÷ 2 = 5.5 ft.

Frequently asked questions

How do I calculate my pool's gallons?

Surface area × average depth × 7.48. For a 32×16 ft rectangle sloping 3 to 8 ft, that's 512 sq ft × 5.5 ft × 7.48 ≈ 21,100 gallons. Round pools use π/4 × diameter² for area; ovals use π/4 × length × width.

Why does pool volume matter?

Every chemical dose — salt, chlorine, acid, stabilizer — is proportional to volume. A 20% volume error means every dose you ever add is 20% off.

What average depth should I use?

For a constant slope, (shallow + deep) ÷ 2 is exact. For a hopper-bottom diving pool the true average is a bit less; using the midpoint overestimates slightly, which is a safe direction for salt.