Pool RatioHow to use it
- Measure the water, not the wall. For depth, measure from the water line to the floor.
- Sloped floors: enter the shallow and deep end; we use the average.
- Round pools: measure straight across through the centre (the diameter).
- Kidney pools: measure the length and the width at the two widest points (A and B), then enter A + B as the width.
Example: a 24 ft round above-ground pool, 4 ft of water
- Area = π × 12² = 452.4 sq ft
- Volume = 452.4 × 4 = 1,810 cu ft
- Gallons = 1,810 × 7.48 = 13,536 gal
About 13,536 gallons (51,241 litres).
Every pool test kit has some error, and products vary in strength, so treat any dose as a starting point: add most of it, circulate, retest, then top up. Never mix chemicals together, and add each one separately to the pool.
Frequently asked questions
How do I calculate how many gallons are in my pool?
Multiply the surface area (sq ft) by the average depth (ft), then by 7.48. Round pools: 3.14 × radius² × depth × 7.48. Oval: 3.14 × (length ÷ 2) × (width ÷ 2) × depth × 7.48. Rectangle: length × width × average depth × 7.48.
How many gallons is a 24 ft round pool?
At 4 ft of water a 24 ft round pool holds about 13,536 gallons. At 52-inch-wall depth (about 4.3 ft of water) it is closer to 14,700 gallons.
Why does pool volume matter?
Every chemical dose is "amount per gallon", so a volume that is 20% off makes every dose 20% off. Measure once, carefully, and save the number.