21 ft round above-ground pool: gallons and litres
A standard 21 ft round above-ground pool with a 52 in wall holds about 9,932 US gallons (37,597 litres) when filled 6 in below the top. Change the size or depth below to match your pool.
Gallons by wall height
| Wall | Water depth | US gallons | Litres | UK gallons | Water weight |
|---|---|---|---|---|---|
| 48 in | 42 in (107 cm) | 9,068 | 34,327 | 7,551 | 75,680 lb |
| 52 in | 46 in (117 cm) | 9,932 | 37,597 | 8,270 | 82,890 lb |
| 54 in | 48 in (122 cm) | 10,364 | 39,231 | 8,630 | 86,490 lb |
Filled right to the top of a 52 in wall it would hold 11,227 gallons — the figure some charts quote. Surface area: 346 ft² (32.2 m²).
Looking after 9,932 gallons
| Raise free chlorine by 1 ppm | 10.2 fl oz of 12.5% liquid chlorine (301 mL) — guidance, follow the label |
|---|---|
| Salt for a salt system (0 → 3,200 ppm) | 265 lb (120 kg), 7 × 40 lb bags |
| Pump flow for an 8-hour turnover | 20.7 GPM (4,700 L/h) |
| Fill time at 6 GPM | 27.6 hours |
| Evaporation at ¼ in a day | about 378 gallons a week |
Work out exact doses with the chlorine and salt calculators, and check your pump with the turnover calculator.
Questions
How many gallons is a 21 ft round pool with a 52 in wall?
About 9,932 US gallons (37,597 litres) filled to 46 in, 6 in below the top of the wall. With a 48 in wall it is 9,068 gallons and with a 54 in wall 10,364.
How many litres is a 21 ft round above-ground pool?
34,327 L with a 48 in wall, 37,597 L with a 52 in wall and 39,231 L with a 54 in wall (8,270 UK gallons for the 52 in wall).
How long does it take to fill a 21 ft round pool?
About 27.6 hours with a 6 gallon-per-minute garden hose for the 52 in wall, or 16.6 hours at 10 GPM.