Calculators
Pool Salt by Pool Size
Not every homeowner has gallonage from the builder — length, width, and average depth in feet get you close with the × 7.48 rule. This preset uses a 20 × 40 ft pool at 5 ft average depth, then the same 2,000 → 3,200 ppm raise as the main calculator.
Switch to gallons in the controls below if you already know the label on the equipment pad. Depth should be average depth, not the deep end alone.
Estimates only; odd shapes and spa spillovers change true volume.
Result
| Pool volume | 29,920 gal |
|---|---|
| Raise salinity by | 1,200 ppm |
| Salt to add | 299.2 lb |
| 40 lb bags (rounded up) | 8 |
| Leftover after bags | 20.8 lb |
About 1 lb of salt per 1,000 gallons raises salinity roughly 120 ppm. Estimates only — confirm with your test kit.
Pool salt and testing supplies
- 40 lb bags of pool salt for saltwater chlorinator systems (opens in new tab)
- Salt test strips or a digital salt meter for ppm readings (opens in new tab)
- A wide-mouth bucket or scoop for pouring salt away from the skimmer (opens in new tab)
- Pool brush to spread piles on the floor while the pump runs (opens in new tab)
Find these on Amazon (opens in new tab)
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