Pool Salt Calculator
Calculate pounds of salt and 40-lb bags to reach your target ppm in a saltwater pool, from pool volume and current salt level.
How this calculator works
Salt dosing is a concentration problem: you are raising the parts-per-million of salt in a known volume of water. The calculator finds the gap between your current and target ppm and converts it to pounds using the weight of your pool water.
Formula: Salt (lbs) = (target ppm − current ppm) ÷ 1,000,000 × gallons × 8.34 lbs/gal. Bags = salt ÷ 40, rounded up.
Worked example
A 15,000-gallon pool at 0 ppm, targeting 3,200 ppm:
- Gap: 3,200 − 0 = 3,200 ppm
- Salt: 3,200 ÷ 1,000,000 × 15,000 × 8.34 ≈ 400.3 lbs
- 40-lb bags: ⌈400.3 ÷ 40⌉ = 11 bags
Reference (raising from 0 ppm)
| Pool gallons | Salt to 3,200 ppm | 40-lb bags |
|---|---|---|
| 10,000 | 267 lbs | 7 |
| 15,000 | 400 lbs | 11 |
| 20,000 | 534 lbs | 14 |
How to find your pool volume
Test your current salt level first. If you do not know your pool’s gallons, use the Pool Gallons Calculator (rectangular) or the Round Pool Calculator, then bring that number here. Add salt gradually and retest after 24 hours of circulation before dosing again.
Frequently asked questions
What salt level should a saltwater pool be?
Most salt chlorine generators run best between 2,700 and 3,400 ppm, with 3,200 ppm a common target. Check your generator's manual — running below its range makes weak chlorine, and running above it can trigger a high-salt fault or accelerate corrosion.
How much salt do I add?
The salt needed depends on your pool's gallons and the gap between current and target ppm. The calculator multiplies that gap by the weight of your pool water: pounds = (target − current) ÷ 1,000,000 × gallons × 8.34.
How do I find my current salt level?
Use a salt test strip, a digital salt meter, or your generator's display. A brand-new pool or one freshly filled reads near zero, so you add the full target amount. Always test before adding — overshooting means draining and refilling to correct.
What kind of salt do I use?
Pool-grade sodium chloride, at least 99 percent pure and non-iodized, sold in 40-pound bags. Avoid rock salt with additives or anti-caking agents, which can stain or cloud the water.
How long until I can test after adding salt?
Broadcast the salt over the pool with the pump running, brush any that settles, and wait 24 hours with the pump circulating before retesting. Salt dissolves and mixes slowly, so an early reading will be misleadingly low.
Estimates only. Verify quantities with your supplier before purchasing.