Pool Salt Calculator
Estimate salt dose for a saltwater pool by volume, current ppm, target ppm, and salt cell brand range.
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About this calculator
Method, formulas, and limits.What this does
Estimates how much pool salt to add to a saltwater pool based on current and target PPM, pool volume, salt type purity, and salt cell brand range. Includes bag count and cost estimates, plus drain-and-refill guidance for over-salted pools.
Who it is for
Pool owners, service technicians, and salt chlorine generator users who need to dose salt accurately to keep their salt cell happy and water chemistry in range.
How it works
Salt dose is computed from the PPM gap between current and target salinity, the pool volume in gallons, and the purity of the salt type. The calculator also compares current PPM against the selected salt cell brand's recommended range and flags when a partial drain and refill is safer than adding salt.
Limitations
Estimates assume a uniform salt concentration and an accurate volume. Actual readings can vary with temperature, fresh water dilution from rain, backwashing, and salt cell calibration.
Key calculations
- Salt Dose Formula
- pounds of salt = (PPM gap × pool volume gallons × 8.34) / 1,000,000 / salt purity
- PPM Gap
- PPM gap = target PPM − current PPM. A negative gap means the pool is over-salted.
- Drain Ratio for Over-Salted Pools
- drain ratio = (current PPM − target PPM) / current PPM, then drain that fraction of the pool volume and refill with fresh water.
Reference ranges
- Typical Salt Cell Range
- Most salt chlorine generators run best between 2,700 and 4,000 PPM, with a common target around 3,200 PPM.
- Freshwater Pool
- Pools without a salt system should stay well below 1,500 PPM to avoid corrosion and cloudy water.
How to use it
- 1.Choose your equipmentSelect a salt cell model preset or a brand profile so the calculator knows the recommended PPM range.
- 2.Enter your volumeType your pool volume manually, or estimate it from the pool shape and dimensions.
- 3.Enter salinity readingsInput current and target salt PPM. The recommended target for most cells is 3,200–3,500 PPM.
- 4.Pick bag size and priceChoose your salt bag size and price to see how many bags you need and the estimated cost.
It depends on your pool volume and the gap between current and target PPM. A 20,000-gallon pool that is 1,000 PPM low needs roughly 170 pounds of 99.8% pure salt.
Most salt chlorine generators recommend 3,000–3,500 PPM, with 3,200 PPM as a common sweet spot. Check your specific cell manual.
Over-salting happens after many refills without draining, or when salt is added without measuring. The solution is a partial drain and refill, not adding more salt.
Yes. Solar, water softener, and rock salt contain more impurities, so you need slightly more of them to reach the same PPM. This calculator accounts for that.