Pool Salt Calculator
Dial in salt for a saltwater chlorine generator. Enter pool volume in gallons or liters, your current salt reading, and the target ppm (3,200 is typical), and get pounds and kilograms of salt to add plus 40 lb bag count.
Example: with Pool volume 15000 · Volume unit US gallons · Current salt level (ppm) 0 · Target salt level (ppm) 3200 → Salt to add: 400.6 lb of pool salt.
- In kilograms181.7 kg
- Bags to buy11 × 40 lb bags
Computed by the calculator below using its default values. Change any input to see your own numbers.
ppm is pounds of salt per million pounds of water, and a gallon weighs 8.345 lb — so 10,000 gallons needs 83.5 lb of salt per 1,000 ppm.
The math behind the salt dose
Parts per million is a weight ratio: 3,200 ppm means 3,200 pounds of salt per million pounds of water. A US gallon of water weighs 8.345 lb, so the dose is gallons × 8.345 × (target − current) ÷ 1,000,000. For a fresh-filled 15,000-gallon pool heading to 3,200 ppm, that is about 400 lb of salt — ten to eleven 40 lb bags. Raising an existing pool from 2,800 to 3,400 ppm takes far less: about 75 lb.
Most saltwater chlorine generators want 2,700–3,400 ppm and run best near 3,200, but the sticker range on your specific cell wins — check the manual before dosing.
Adding salt the right way
Use pool-grade salt (99%+ pure sodium chloride, no anti-caking additives or iodine) and broadcast it around the shallow end with the pump running; it dissolves over several hours. Add about 80% of the computed dose first, circulate for 24 hours, retest, then top up. Salt does not evaporate or get consumed by the cell — it only leaves through splash-out, backwash, and rain dilution — so overshooting is hard to undo without draining water. If the reading comes back above target, dilution with fresh water is the only fix.
How it’s calculated
Salt (lb) = gallons × 8.345404 lb/gal × (target ppm − current ppm) ÷ 1,000,000. Liters convert at 3.785411784 L per US gallon (equivalently, kg of salt = liters × Δppm ÷ 1,000,000). Kilograms = lb × 0.45359237. Bags round up at 40 lb each.
Assumes your volume estimate and test strip are accurate — both drift, so add about 80% of the dose, circulate 24 hours, and retest before adding the rest.
Salt to raise 10,000 gallons
| Increase | Salt needed |
|---|---|
| +500 ppm | 42 lb |
| +1,000 ppm | 83 lb |
| +2,000 ppm | 167 lb |
| +3,200 ppm (fresh fill) | 267 lb |
Computed with lb = 10,000 gal × 8.345 × Δppm ÷ 1,000,000; rounded to the pound.
Common mistakes
- Dumping the full computed dose at once — test-strip and volume errors compound, and removing salt means draining water.
- Using water-softener or rock salt with anti-caking additives, which can stain surfaces and foul the cell.
- Guessing pool volume badly: a 'roughly 15,000 gallon' pool that is really 12,000 overshoots by 27%.
- Chasing a low reading right after rain or backwashing before the water has fully mixed.
Frequently asked questions
What is the pool salt formula?
Pounds of salt = gallons × 8.345 × (target ppm − current ppm) ÷ 1,000,000. For 10,000 gallons going from 0 to 3,200 ppm: 10,000 × 8.345 × 3,200 ÷ 1,000,000 ≈ 267 lb.
What should my pool salt level be?
Most saltwater generators specify 2,700–3,400 ppm with 3,200 as the sweet spot. Your cell's manual overrides any generic number — some systems run as low as 2,000 ppm.
Does pool salt evaporate or get used up?
No. The generator converts salt to chlorine and back in a closed loop, and evaporation leaves salt behind. Levels only drop through splash-out, backwashing, leaks, and rain dilution, so you add salt occasionally, not continuously.
What if my salt level is too high?
Partially drain and refill with fresh water — there is no chemical that removes salt. That is why this calculator (and every cell manufacturer) recommends dosing in stages and retesting.