Pool Salt Calculator
Enter your pool volume and your current and target salt level to get the exact pounds of pool salt to add, plus how many 40-pound bags to buy for your salt water generator.
Not sure? Use the pool volume calculator first.
Default 3,200 ppm. Check your salt cell manual.
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pounds of pool salt
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40-lb bags to buy
Dose conservatively. Salt only leaves the pool by dilution, so you cannot easily lower it. Add gradually with the pump running, brush to dissolve, wait about 24 hours, and retest before adding more. Use pool-grade salt only, never water-softener pellets or rock salt.
Gear for a -gallon salt pool
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How Much Salt Your Pool Needs
Adding salt to a pool is a straightforward calculation. The tool takes the gap between your target salt level and your current salt level in parts per million, multiplies it by your pool volume in gallons and by 8.34, the weight of a gallon of water in pounds, then divides by one million to turn parts per million into actual pounds of salt. If you are already at or above your target, you do not need any salt. The result is rounded up into whole 40-pound bags, since that is how pool salt is sold, so you know exactly what to grab at the store.
What Salt Level to Target
Most salt water generators are built to run somewhere between roughly 2,700 and 3,400 ppm, and a common target is 3,000 to 3,200 ppm. The exact ideal depends on your specific salt cell, so the manual is the final word. Run too low and the cell cannot produce chlorine, which leaves your water unsanitized. Run too high and you may trip a high-salt warning and speed up corrosion of metal fittings and the cell itself. Aiming for the middle of your cell range gives you a comfortable buffer in both directions, which is why 3,200 ppm is a sensible default for many pools.
You Can Add Salt, but You Cannot Easily Remove It
This is the single most important thing to understand about pool salt. Salt does not evaporate and it is not consumed by the generator, it simply cycles through the cell as it makes chlorine and stays in the water. The only way salt leaves your pool is by dilution: rain overflow, splash-out, backwashing the filter, or draining. That means there is no chemical you can add to lower a high salt reading. If you overshoot, your only fix is to drain part of the pool and refill with fresh water, which wastes both water and the other chemicals you have balanced. For that reason it pays to dose conservatively. Add a little less than the calculator suggests, let it dissolve and mix, retest, and top up only if you are still short. It is always easier to add a few more pounds than to drain a pool.
How to Add Pool Salt the Right Way
Start with the pump running so the water is circulating. Broadcast the salt slowly across the surface of the pool, or pour it into the shallow end, and use a pool brush to push it around and help it dissolve rather than letting it pile up on the floor. Avoid dumping salt directly into the skimmer, which sends a concentrated slug of salty water straight through your equipment. Most manufacturers recommend keeping the pump running for about 24 hours and waiting until the salt is fully dissolved before turning the salt cell back on. Then test the salt level once it has mixed evenly, and only resume normal chlorine production when the reading is in your cell range. Always use pool-grade salt, high-purity sodium chloride sold in bags marked for pool or salt water generator use. Skip water-softener pellets, rock salt, and table salt, which carry impurities that can stain the pool, cloud the water, or damage the cell.
Salt Is Only Part of the Picture
A salt water generator quietly makes chlorine from the salt in your water, but it does not balance the rest of your chemistry. You still need to test and adjust pH, total alkalinity, cyanuric acid (CYA), and calcium hardness on a regular schedule. Salt pools have a tendency to push pH upward as the cell runs, so many owners add acid more often than they expect. CYA still matters too, because it stabilizes the chlorine your cell produces against sunlight. Treat the salt reading as one number among several, retest your salt after heavy rain or a big top-off, and keep the full set of readings in range for clean, comfortable water all season.
Balance the rest of your water:
Frequently Asked Questions
How much salt do I need to add to my pool?
It depends on your pool volume and how far below target your current salt level is. The math is pounds equals the ppm gap times your gallons times 8.34, divided by one million. For example, a 20,000-gallon pool that needs to climb from 2,800 to 3,200 ppm needs about 67 pounds, or roughly two 40-pound bags. This calculator does that for you and tells you how many 40-pound bags to buy.
What salt level should a salt water pool run at?
Most salt water generators are designed to run between about 2,700 and 3,400 ppm, with 3,000 to 3,200 ppm a common sweet spot. Always check the manual for your specific salt cell, because the ideal target varies by brand and model. Running too low starves the cell and it stops producing chlorine, while running too high can trigger a high-salt warning and accelerate corrosion. Aim for the middle of your cell range.
What happens if I add too much salt?
Salt does not evaporate or get used up. It only leaves your pool through dilution, meaning rain overflow, splash-out, backwashing, or draining. So if you overshoot your target, the only way to bring it back down is to drain part of the pool and refill with fresh water. That wastes water and chemicals, so always dose conservatively, add a little less than the calculator says, run the system, and retest before adding more.
How long after adding salt can I run the generator?
Add the salt with the pump running, then brush it around to help it dissolve and circulate. Most manufacturers recommend waiting about 24 hours, with the pump running, before turning the salt cell back on, so the salt is fully dissolved and evenly mixed. Running the generator before the salt dissolves can give a false low reading and may damage the cell. Retest the salt level after it has mixed and only then resume normal chlorine production.
What kind of salt should I use in a pool?
Use pool-grade salt, which is high-purity sodium chloride, usually 99 percent or better, and free of additives like iodine or anti-caking agents. It comes in 40-pound bags labeled for pool or salt water generator use. Avoid water-softener pellets, rock salt, and table salt, which can contain impurities that stain the pool, cloud the water, or harm the salt cell. Pool salt dissolves cleanly and is what your generator is designed for.
Why does my salt level read low after heavy rain?
Rain dilutes your pool. When a storm overflows the pool or you have to lower the water afterward, you remove salty water and replace it with fresh, so the salt concentration drops. Splash-out, backwashing a filter, and topping off with a hose do the same thing over time. That is why salt is a level you periodically top up rather than set once. Test after big weather and add salt to bring it back to your cell target.
Do I still need to test and balance other chemistry in a salt pool?
Yes. A salt water generator makes chlorine, but it does not manage the rest of your water. You still test and adjust pH, total alkalinity, cyanuric acid (CYA), and calcium hardness. Salt pools tend to push pH up, so many owners add acid regularly. CYA is also important, since it protects the chlorine your cell produces. Use our other calculators to keep the full picture balanced, not just the salt.