An 18 × 33 ft oval above-ground pool with 52 in walls holds about 13,380 US gallons (50,640 L) when filled to 46 in of water, about 6 in below the top rail. Volume depends on the water depth, not the wall height, so measure your water and check the table.
| Water depth | US gallons | Litres |
|---|---|---|
| 44 in of water | 12,800 gal | 48,440 L |
| 46 in of water | 13,380 gal | 50,640 L |
| 48 in of water | 13,960 gal | 52,840 L |
Formula: 33 × 18 × 3.83 ft × 5.87 = 13,378 gal. Oval pools with straight sides hold a little more than a true ellipse; use the manufacturer’s figure if it differs.
13,378gal
About 50,640 L
Average depth 3.8 ft
Formula: length × width × average depth × 5.87.
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Pool Calc for iPhoneComing soon to the App Store| Job | Amount |
|---|---|
| Raise chlorine 1 ppm | 17 fl oz of 10% liquid chlorine |
| Stabilizer 0 → 30 ppm | 3.4 lb |
| Salt 0 → 3,200 ppm | 359 lb (9 bags) |
Full dose tables for a pool this size: liquid chlorine for 15,000 gallons, salt and stabilizer. Or put 13,378 gallons straight into the pool chemical calculator.
Manufacturer capacities are usually given at a stated fill level, and liners stretch. To confirm your real volume, add a known amount of salt or stabilizer and see how much the test reading moves: the volume that explains that change is your pool.
About 13,380 gallons at 46 in of water.
About 50,640 L at 46 in (117 cm) of water.