How it works
Salt dosing is the same mass math as any other ppm chemical: pounds = ppm change × gallons × 8.345 ÷ 1,000,000, adjusted for 99% purity. For 10,000 gallons, each 100 ppm takes about 8.4 lb of salt.
Which target to use
Salt chlorine generators each specify their own operating range. Many sit somewhere around 2,700–3,400 ppm, and 3,200 ppm is a common ideal. Some models run lower or higher. Use the number in your manual. It overrides our default.
If salt is too high
Only water replacement lowers salt. The calculator shows the share of water to replace, assuming your fill water is close to salt-free. Rain and splash-out lower salt gradually over a season.
Tips
- Turn the cell off while adding salt, brush it toward the main drain, and let it circulate 24 hours before retesting.
- Salt doesn’t get used up. Losses come from splash-out, backwashing and rain dilution, so most pools need only small top-ups each year.
- A saltwater pool is still a chlorine pool. Keep testing free chlorine and CYA.
Assumptions and limitations
- Assumes pool salt of 99% or higher purity.
- Your generator's manual sets the target; our 3,200 ppm default is only a common starting point.
- Dilution assumes your fill water is close to salt-free.
- Salt cell displays drift with temperature and cell age; use a separate salt test before adding salt.
Key terms
Common questions
How much salt does a new 20,000-gallon pool need?
To reach 3,200 ppm from zero, about 540 pounds, or roughly 13 to 14 bags of 40 lb. Most fill water has some salt already, so test first and add a bit less.
Why does my salt cell reading differ from my test strip?
Cells estimate salt from electrical conductivity, which drifts with temperature and as the cell plates age. A separate salt test is the better guide for adding salt.
What kind of salt should I use?
Pool salt or another sodium chloride of 99% or higher purity, without anti-caking agents or iodine. Water-softener pellets dissolve slowly and some contain additives.
Sources and methodology references
- NIST SP 811 unit conversions, National Institute of Standards and TechnologyPound–gram and gallon–liter conversions used for ppm math.
Published October 2, 2026. Results are estimates. See how our calculators work.
Spotted a wrong result or an outdated source? Report a problem with this calculator.
Related tools
- Chlorine calculatorSee how much chlorine to add to reach the right free chlorine level for your pool's stabilizer, in ounces, gallons or pounds of the product you actually have.
- CYA (stabilizer) calculatorGet the stabilizer amount to raise CYA, or the share of water to replace to lower it, plus the free chlorine level your new CYA calls for.
- Pool volume calculatorWork out how many gallons your pool holds from a few tape-measure readings. Every chemical dose depends on this number.
- Pool shock calculatorWork out the shock level your pool actually needs and how much product gets you there. For algae it depends on your stabilizer; for a "chlorine smell" it depends on combined chlorine.
Related guides
- Cyanuric Acid (Pool Stabilizer): How Much You Need and Why It MattersStabilizer stops sunlight from destroying chlorine, but it also raises the chlorine level your pool needs. How CYA works, good levels, and how to raise or lower it.Read the guide (3 min)
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- How to Shock a Pool (and How Much Shock You Actually Need)How to shock a pool so it actually works. Find the right chlorine level for your stabilizer, choose a product, and hold the level until the job is done.Read the guide (4 min)
- Pool Water Chemistry for Beginners: What Each Test Number MeansWhat free chlorine, pH, alkalinity, CYA, calcium hardness and combined chlorine actually tell you, which ones matter most, and what order to fix them in.Read the guide (4 min)