How to use the pool salt calculator
Enter your pool's volume in gallons, the salt reading from your test strip, meter or generator display, and the target level from your chlorine generator's manual. The calculator gives the pounds of salt to add and how that breaks down into bags. Because salt can't be taken out without draining water, it suggests adding the full bags first, letting them dissolve, retesting and only then adding the remainder.
If you don't know your pool's volume, the pool volume calculator works it out from the size and depth.
The formula
salt (lb) = gallons × (target ppm − current ppm) × 8.3454 ÷ 1,000,000
ppm is parts per million by weight, and a US gallon of water weighs about 8.345 lb. The calculator's results match the salt table in Pentair's IntelliChlor guide to the hundredth of a pound.
Worked example: 15,000 gallons from 500 to 3,200 ppm
- Increase needed: 3,200 − 500 = 2,700 ppm.
- Salt: 15,000 × 2,700 × 8.3454 ÷ 1,000,000 = 338 lb.
- In 40 lb bags that's 8.45 bags: add 8 bags (320 lb), let them dissolve for a day, retest, then add up to 18 lb more.
- Each 40 lb bag raises this pool by about 320 ppm.
Salt per 10,000 gallons
| Raise by | Salt | 40 lb bags |
|---|---|---|
| 500 ppm | 42 lb | 1.0 |
| 1,000 ppm | 83 lb | 2.1 |
| 2,000 ppm | 167 lb | 4.2 |
| 3,200 ppm (from fresh water) | 267 lb | 6.7 |
Adding salt the right way
- Turn the generator off (or to its lowest setting) while the salt dissolves, as most manuals instruct.
- Pour around the shallow end and brush it toward the main drain with the pump running. Don't add salt through the skimmer.
- Wait about 24 hours, then retest before adding more. Test strips and generator readings can differ; a second test method helps.
- Top up after rain and backwashing. Salt only leaves the pool with water: splash-out, backwashing, draining and overflow from heavy rain.
Common mistakes
- Guessing the volume. A 20% error in gallons is a 20% error in salt. Measure the pool.
- Adding it all at once. Readings are rarely exact, and too much salt means draining.
- Trusting a new cell's reading blindly. Generators estimate salt from conductivity, which drifts with temperature and cell scale. Confirm with a separate test.
Questions people ask
How much salt do I need for my pool?
Pounds of salt = gallons × (target ppm − current ppm) × 8.345 ÷ 1,000,000. A 15,000 gallon pool at 500 ppm going to 3,200 ppm needs about 338 lb, roughly eight and a half 40 lb bags.
How much salt for a 10,000 gallon pool?
From zero to 3,200 ppm: about 267 lb (between six and seven 40 lb bags). Pentair's IntelliChlor guide lists 300 lb to take 10,000 gallons from 0 to 3,600 ppm.
What salt level should a saltwater pool be?
It depends on your chlorine generator. Hayward's AquaRite manual lists an ideal range of 2,700 to 3,400 ppm; Pentair IntelliChlor guides give tables for their own target. Check the label on your control box or the manual.
How long after adding salt can I swim?
Brush the salt toward the main drain and run the pump so it dissolves; most manufacturers say to wait about 24 hours for salt to fully dissolve and mix before turning the chlorine generator back on or retesting.
What kind of salt should I use in a pool?
Pool-grade sodium chloride that's at least 99% pure, without anti-caking agents or iodine. Rock salt and water-softener pellets with additives can stain or cloud the water.
Sources and assumptions
- Pentair IntelliChlor Installation and User's Guide, salt table: 10,000 gal from 0 to 3,600 ppm = 300.43 lb (this calculator reproduces the table)
- Hayward AquaRite owner's manual: ideal salt 2,700-3,400 ppm
- Pounds = gallons × Δppm × 8.3454 ÷ 1,000,000 (ppm by weight; 8.3454 lb per US gallon of water). Assumes pure sodium chloride.
Last reviewed 27 October 2026. Every formula on this page is checked against the worked example above in our automated tests. Found a problem? Tell us.