How the pool salt calculator works
Salt level is measured in parts per million (ppm) by weight. A gallon of water weighs 8.34 lb, so the salt you need is:
pounds of salt = gallons × 8.34 × (target ppm − current ppm) ÷ 1,000,000
For a 10,000 gallon pool going from 0 to 3,200 ppm that is 10,000 × 8.34 × 3,200 ÷ 1,000,000 = 267 lb, or 7 bags of 40 lb.
How much salt for my pool size?
Salt needed to bring fresh water (0 ppm) up to 3,200 ppm. Tap a size for the full table with other starting levels.
| Pool size | Salt needed | 40 lb bags | One bag adds |
|---|---|---|---|
| 5,000 gal | 133 lb | 4 | 959 ppm |
| 7,500 gal | 200 lb | 5 | 639 ppm |
| 10,000 gal | 267 lb | 7 | 480 ppm |
| 12,000 gal | 320 lb | 8 | 400 ppm |
| 15,000 gal | 400 lb | 10 | 320 ppm |
| 18,000 gal | 480 lb | 12 | 266 ppm |
| 20,000 gal | 534 lb | 14 | 240 ppm |
| 25,000 gal | 667 lb | 17 | 192 ppm |
| 30,000 gal | 801 lb | 20 | 160 ppm |
| 40,000 gal | 1,068 lb | 27 | 120 ppm |
How much salt in litres and kilograms?
Choose Metric at the top of the calculator to enter litres and metres and get the answer in kilograms and 20, 25 or 10 kg bags. A litre of water weighs one kilogram, so the sum is simpler: kilograms of salt = litres × (target ppm − current ppm) ÷ 1,000,000. Salt needed to bring fresh water up to 3,200 ppm:
| Pool size | Salt needed | 20 kg bags | One bag adds |
|---|---|---|---|
| 20,000 L | 64 kg | 4 | 1,000 ppm |
| 30,000 L | 96 kg | 5 | 667 ppm |
| 40,000 L | 128 kg | 7 | 500 ppm |
| 50,000 L | 160 kg | 8 | 400 ppm |
| 60,000 L | 192 kg | 10 | 333 ppm |
| 80,000 L | 256 kg | 13 | 250 ppm |
| 100,000 L | 320 kg | 16 | 200 ppm |
Not sure how much water your pool holds?
Choose Measure it in step 1 and enter the length, width and depth. The calculator uses the average of the shallow and deep ends and 7.48 gallons per cubic foot (1,000 litres per cubic metre). Round and oval pools use the area of a circle or ellipse.
What salt level should I aim for?
It depends on your salt chlorine generator. Hayward says its AquaRite works best at about 3,200 ppm; Pentair and Jandy manuals recommend 3,000 to 3,500 ppm. See the pool salt level chart for the ranges and sources.
Questions people ask
How much salt do I add to a 10,000 gallon pool?
A 10,000 gallon pool with no salt in it needs about 267 lb of salt to reach 3,200 ppm, which is 7 bags of 40 lb. If the water already has some salt, you need less: enter your current reading in the calculator.
How much does one 40 lb bag of salt raise the level?
One 40 lb bag raises a 10,000 gallon pool by about 480 ppm, a 15,000 gallon pool by about 320 ppm and a 20,000 gallon pool by about 240 ppm.
How much salt do I add to a 50,000 litre pool?
A 50,000 litre pool with no salt in it needs about 160 kg of salt to reach 3,200 ppm, which is 8 bags of 20 kg. Switch the calculator to metric to work in litres, kilograms and metres.
What should the salt level be in a saltwater pool?
Most salt chlorine generators want between 2,700 and 3,400 ppm, with about 3,200 ppm as the usual target. Some systems ask for 3,000 to 3,500 ppm, so check the manual for your model.
What if I added too much salt?
Salt does not evaporate or get used up, so the only way to lower it is to replace some pool water with fresh water. To go from 4,000 ppm down to 3,200 ppm you would replace about 20% of the water. The calculator works this out when your current level is above the recommended band.
What kind of salt do I use?
Use salt sold for pools: sodium chloride that is at least 99% pure, with no iodine and no anti-caking additives. Rock salt and salt with additives can stain surfaces or cloud the water.
How do I add the salt?
With the pump running, pour the salt around the edge of the pool, away from the skimmer, and brush any piles until they dissolve. Add most of the calculated amount first, let the water circulate for about 24 hours, then retest and add the rest if it is still needed.