How many gallons in a 18 ft round pool?
A 18 ft round above-ground pool holds about 7,600 gallons (28,800 liters) with 4 ft of water.
By water depth
| Water depth | US gallons | Liters |
|---|---|---|
| 3.5 ft (42 in) | 6,700 | 25,200 |
| 4 ft (48 in) | 7,600 | 28,800 |
| 4.5 ft (54 in) | 8,600 | 32,400 |
Formula: 3.14 × 9² × depth × 7.48. Measure the water, not the wall: water usually sits 4–6 inches below the top rail.
At 4 ft of water
Dose this pool: full chemical calculator · liquid chlorine · salt
Other round pool sizes
10 ft round · 12 ft round · 15 ft round · 21 ft round · 24 ft round · 27 ft round · 28 ft round · 30 ft round · 33 ft round
Questions pool owners ask
How many gallons are in a 18 ft round pool?
About 7,600 gallons at 4 ft (48 in) of water. At 3.5 ft it holds about 6,700 gallons and at 4.5 ft about 8,600. Formula: 3.14 × 9² × depth × 7.48.
How much salt does a 18 ft round pool need?
Starting from fresh water, about 203 lb of pool salt (6 × 40 lb bags) reaches 3,200 ppm at 4 ft of water. Add 80–90% first, then test after 24 hours.
How much liquid chlorine for a 18 ft round pool?
Raising free chlorine by 1 ppm takes about 9.7 fl oz of 10% liquid chlorine, or 15.8 fl oz of 6% bleach.
How long does it take to fill?
With a garden hose at about 10 gallons per minute, roughly 13 hours. Two hoses halve that.