Pool salt calculator: find how much salt to add to your pool to reach your target salinity, in pounds, kilograms and bags, for any pool size in gallons or litres. Enter the values shown in the calculator to get a practical planning estimate.
Free interactive calculatorWater Chemistry
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FREE ONLINE CALCULATOR
Pool Salt Calculator
Estimate how much pool salt may be needed to raise salinity from a measured level to your salt system's target.
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YOUR ESTIMATE
Estimated pool salt
Planning estimate
Salt needed—pounds of salt
Metric amount—kilograms
Salt increase—ppm
Equivalent bags—bags at your selected size
Important: Salt requirements vary by saltwater system. Check the equipment manual and product label, add salt in a controlled way, allow circulation and retest before making another adjustment.
ABOUT THIS TOOL
What this calculator helps with
Water Chemistry
The pool salt calculator (also called a salt pool calculator or salt water pool calculator) estimates how much salt to add to a pool to reach your target salinity. Enter the pool volume in gallons or litres, your current salt reading and the target level from your salt system manual, and it shows the salt needed in pounds, kilograms and bags.
Why this calculation matters
Saltwater chlorine generators work within a manufacturer-specified salinity range. Too little salt makes the cell underperform or shut down, and too much cannot be removed with chemicals. Working from a measured reading and a reliable pool volume is far better than adding bags by guesswork.
Details to have ready
Pool water volume, ideally measured or worked out from the pool's real dimensions.
The current salt level in ppm from a reliable test strip, meter or salt test kit.
The target salinity stated in your salt chlorine generator manual.
The size of the salt bags you plan to buy (for example 40 lb or 20 kg).
How to prepare
Calculate or confirm the pool volume in gallons or litres.
Test the current salt level and note the reading in ppm.
Enter the target salinity from your generator manual.
Add the salt in stages, brush until dissolved, circulate and retest before adding more.
Note: The calculator uses an approximate salt mass relationship. Your salt system manual and the product label should guide the final adjustment, and the water should be retested after the salt has dissolved and circulated.
CALCULATION GUIDE
How to calculate pool salt needed
The salt estimate is based on the amount of water in the pool and the change in salinity you want to make.
Salt needed (lb) ≈ Pool volume (gallons) × Salt increase (ppm) ÷ 120,000
For example, a 15,000-gallon pool moving from 500 ppm to 3,200 ppm has a 2,700 ppm increase. The calculator estimates about 337.5 lb of salt before you compare that figure with your salt-generator manual and the salt product label.
How many bags of pool salt do I need?
Enter your actual bag size to see the equivalent number of bags. The result can be fractional because a calculated amount should be measured rather than automatically rounded up.
POOL SALT CHART
Pool salt chart: how much salt to add by pool size
This salt chart shows how much salt to add to common pool sizes to reach an example target of 3,200 ppm, from an empty pool and from a pool that already holds some salt. It answers questions such as how much salt for a 15,000 gallon pool or how many bags of salt for a 20,000 gallon pool.
Pool salt chart: salt needed to reach 3,200 ppm (40 lb bags)
Pool size (US gal)
From 0 ppm (+3,200)
From 2,000 ppm (+1,200)
From 2,800 ppm (+400)
10,000
267 lb (6.7 bags)
100 lb (2.5 bags)
33 lb (0.8 bags)
15,000
400 lb (10.0 bags)
150 lb (3.8 bags)
50 lb (1.2 bags)
20,000
533 lb (13.3 bags)
200 lb (5.0 bags)
67 lb (1.7 bags)
25,000
667 lb (16.7 bags)
250 lb (6.2 bags)
83 lb (2.1 bags)
30,000
800 lb (20.0 bags)
300 lb (7.5 bags)
100 lb (2.5 bags)
Example target of 3,200 ppm. Your salt system may specify a different target, so use the figure in your manual. Amounts use salt lb ≈ gallons × ppm increase ÷ 120,000.
Pool salt calculator in litres and kilograms
Salt needed (kg) ≈ Pool volume (litres) × Salt increase (ppm) ÷ 1,000,000
A 50,000 litre pool going from 0 to 3,200 ppm needs about 160 kg of salt. Ppm is the same as mg/L, so a reading of 3,200 ppm means 3,200 mg of salt per litre of water.
How to add pool salt
Test the current level with a salt meter, test strip or kit, and confirm the target in your salt system manual.
Turn the pump on and pour the salt around the pool, then brush it until it dissolves.
Add large amounts in stages, circulate, and retest before adding more.
Do not use more salt than needed. Salt does not leave the water, and the only way to lower it is to drain and refill.
Not sure how much water you have? Use the pool volume calculator first, then enter that figure above.
COMMON QUESTIONS
About Pool Salt Calculator
How much salt should I add to my pool?
Enter the pool volume, current salt level and the target from your salt system manual. The calculator estimates the salt needed for the difference in ppm. As a guide, raising a 15,000 gallon pool from 0 to 3,200 ppm takes about 400 lb of salt. Add it in stages and retest, because the right amount depends on an accurate reading.
How much salt do I need for a 15,000 gallon pool?
To go from 0 to 3,200 ppm in a 15,000 gallon pool you need about 400 lb, which is ten 40 lb bags. If the pool already reads 2,000 ppm, the 1,200 ppm increase needs about 150 lb, or just under four 40 lb bags. Your generator manual gives the correct target for your system.
How many bags of salt for a 20,000 gallon pool?
Raising a 20,000 gallon pool from 0 to 3,200 ppm takes about 533 lb of salt, which is roughly 13 to 14 bags of 40 lb. Most pools already hold some salt, so test first and only add the difference. For a 30,000 gallon pool the same increase is about 800 lb, or 20 bags.
How much salt do I add to my pool in litres or kilograms?
Salt in kilograms is about litres × ppm increase ÷ 1,000,000. A 50,000 litre pool going from 0 to 3,200 ppm needs about 160 kg of salt. Change Volume units to litres in the calculator and it works this out for you, with the result in both pounds and kilograms.
What does ppm mean for pool salt?
Ppm means parts per million, which for pool water is the same as milligrams per litre (mg/L). A salinity of 3,200 ppm means 3,200 mg of salt in each litre of water. Salinity calculators, test strips and generator manuals all use ppm.
What salt level does a salt water pool need?
It depends on the salt chlorine generator. Many systems specify a target in the low-to-mid 3,000s ppm, but the range differs between brands and models, so use the figure in your manual and the cell's own display or test strip as a cross-check. The same applies to Hayward, Intex and other brand systems: enter the target your manual gives.
How do I add salt to a pool?
Run the pump, pour the salt around the perimeter or into the deep end, and brush it until it dissolves. Keep the pump running so it circulates, then retest after the time your generator manual recommends before adding more. Avoid putting salt into the skimmer or leaving it in piles on the floor.
What if my pool has too much salt?
Salt does not break down or evaporate, so the only way to lower salinity is to drain some water and refill with fresh water. Use the calculator before you add salt, work in small steps, and retest so you do not overshoot your target.
How many bags of pool salt do I need?
Enter your bag size in the calculator to see the equivalent number of bags. The answer can be fractional, so measure the salt rather than automatically rounding up to a whole bag, which could push the level past the target.
Can I use a salt water pool calculator for any pool?
Yes. The calculation depends only on volume and the ppm change, so it works for in-ground, above ground, rectangle, round or oval pools. Use the pool volume calculator first if you are not sure how much water your pool holds.
How much salt should a pool calculator estimate?
The calculation moves the measured salt level toward the target. It uses the pool volume and the ppm difference, and shows the result in pounds, kilograms and bags so you can compare it with the size of the bags you plan to buy.
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