Pool Salt Calculator
Enter your pool volume, current salt reading from a test strip or meter, and the target ppm for your salt cell — instantly see how many pounds (or kg) of pool-grade salt to add.
Unit system
gal
ppm
ppm
Add this amount of pool-grade salt (NaCl) to reach your target level
- 1
Ppm increase needed
3,200 − 800 = 2,400 - 2
Pool volume in litres
15,000 × 3.7854 = 56,781.2 - 3
Salt needed (kg)
56,781.2 × 2,400 ÷ 1 000 000 = 136.27481 ppm = 1 mg/L; mass (kg) = volume (L) × ppm ÷ 1 000 000. - 4
Salt to add (lbs)
136.2748 × 2.20462 = 300.4
How does this calculator work?
Salt needed (kg) = Pool volume (L) × ppm increase ÷ 1 000 000. For gallons and lbs, convert first: 1 gal = 3.785 L, 1 kg = 2.205 lb. Most salt cells target 2 700–3 400 ppm. Salt does not get consumed — only dilution reduces it. Always use 99%+ NaCl pool-grade salt.
Formula
How this is calculated
Salt dissolves evenly in pool water, so concentration (in ppm = mg/L) is purely a mass-per-volume ratio. To raise the concentration by Δ ppm across V litres, you need V × Δ / 1 000 000 kilograms of pure NaCl. Pool salt is typically 99.8% sodium chloride, so this formula is accurate for standard pool-grade salt bags.
For US-gallon users, gallons are converted to litres first (1 US gal = 3.785 L), and the resulting mass is converted to pounds (1 kg = 2.205 lb) for display. The bag count assumes the common 40-lb bag size in the US and 25-kg bags in metric markets — adjust if your bags differ.
Most salt-chlorine generators (salt cells) work best in the 2 700–3 400 ppm range — check your specific cell manufacturer's recommendation. Salt level only decreases through dilution (rain, splash-out, backwash) or bather carry-out; it is never consumed by the chlorinator. Once you reach your target, the level stays stable until you add or remove water.
Frequently asked questions
Use pool-grade or water-softener NaCl (at least 99% pure, no iodine or anti-caking agents). Avoid rock salt or table salt, which contain additives that can stain surfaces or cloud the water.
Use a digital salt meter or a salt test strip. Pool-store photometers are most accurate. Readings can vary ±5–10% across meters, so calibrate or use the same device consistently.
The only way to reduce salinity is to dilute the pool: drain some water and refill with fresh water. Partially replace 10–20% of pool volume, then re-test. This calculator cannot help with a too-high level — a dilution ratio calculator handles that.
Also known as
TG we-Calculate Editorial Team. (2026). Pool Salt Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/pool-salt-calculator
TG we-Calculate Editorial Team. "Pool Salt Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/pool-salt-calculator.
TG we-Calculate Editorial Team, "Pool Salt Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/pool-salt-calculator
@misc{wecalculate_pool_salt_calculator, title = {Pool Salt Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/pool-salt-calculator}}, year = {2026}, note = {TG we-Calculate} }
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