What this calculator does
Pool salt needed works out how much salt to add to a saltwater pool to reach a target concentration. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaSalt needed = pool volume × (target ppm − current ppm) × 0.0037854 g per gallon-ppm (1 ppm = 1 mg/L)
The inputs explained
| Field | What to enter |
|---|---|
| Pool volume (US gal) | A number, measured in US gal. Starts at 20000. |
| Current salt level (ppm) | A number, measured in ppm. Starts at 0. |
| Target salt level (ppm) | A number, measured in ppm. Starts at 3200. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with pool volume
Every other input is held at the calculator’s starting values while pool volume varies. Select any row to load that scenario into the calculator.