Pool Salt Calculator

Saltwater pools need a precise salt concentration to keep the chlorine generator producing and the water comfortable. Enter your pool dimensions, current ppm reading, and target — we'll tell you exactly how many pounds of pool salt to add and how many 40 lb bags to pick up at the store.

Pool Salt Calculator

Pool shape

Length (ft)

Width (ft)

Average depth (ft)

Current salt level (ppm)

Target salt level (ppm)

Salt Needed

Pool volume—

ppm increase needed—

Pounds of salt—

40 lb bags (rounded up)—

Ideal pool salt range is 2,700–3,400 ppm; most chlorine generators run best right at 3,200 ppm. Test your salt level with a digital meter or strips before adding — too much salt can corrode pool equipment and decking, and the only fix is partial water replacement.

How Saltwater Pools Work

A saltwater pool isn't chlorine-free — it generates its own chlorine on demand from dissolved salt using an electrolytic chlorine generator (a.k.a. salt cell). The cell needs the right salt concentration to operate, typically 3,000–3,400 ppm. Below that, the generator under-produces chlorine and usually flashes an error light. Above 3,500 ppm there's no chlorine benefit, just creeping corrosion risk on metal pool components.

How to Calculate Salt Needed

The math: lbs of salt = gallons × (target − current ppm) × 0.00000835. A 20,000-gallon pool needing to climb from 2,800 to 3,200 ppm needs roughly 67 lbs of salt — about two 40-lb bags. Always under-dose slightly, run the pump for 24 hours to fully circulate, retest, and top up. Overshooting is much harder to undo than topping up later.