Pool Salt Calculator

Q: Can I use table salt or rock salt in my pool?

No. Use sodium chloride that is more than 99% pure , such as salt sold for pools or water softeners. Do not use rock salt, iodized salt, or salt with anti-caking additives. 1 Both can cloud your water or damage your equipment.

Q: How do I test my pool's salt level?

You can test your salt level with salt test strips , a digital salt meter , or a drop-based test kit . Many salt water generators also show the salt reading on their control panel. Test your water before using this calculator so you get an accurate result.

Q: How long does it take for pool salt to dissolve?

Run the pump for 24 hours after adding salt so it spreads evenly through the pool; a generator's salt display may also take 24 hours to catch up. 1 Pour the salt into the shallow end and brush any piles that settle on the bottom. Wait a full day and retest your water before adding more salt.

Q: What does ppm mean?

PPM stands for parts per million . It measures how much salt is dissolved in your water. For example, 3,200 ppm means there are 3,200 parts of salt for every one million parts of water.

Q: How does the pool salt formula work?

The formula is: Salt (lbs) = Pool Volume (gal) × 8.34 × (Target ppm − Current ppm) ÷ 1,000,000 . The number 8.34 is the weight of one gallon of water in pounds. The U.S. Geological Survey lists pure water at 60°F as weighing 62.366 pounds per cubic foot. 3 A U.S. gallon is 231 cubic inches, so a gallon of water at that temperature weighs about 8.34 pounds. The formula finds the weight of salt needed to raise your pool's salinity from its current level to your target level.

Q: What if my current salt level is higher than my target?

The calculator will tell you that no salt needs to be added . If your level is too high, the only way to lower it is to drain some pool water and replace it with fresh water. You cannot add a chemical to remove salt.

Q: Does rain or evaporation change my salt level?

Yes. Rain adds fresh water , and salt is lost mainly when water is added or drained, through splashing, backwashing, or draining after rain. 1 Salt is not lost to evaporation, so evaporation raises the concentration until the water is topped up. Retest your salt level after heavy rain or long dry spells.

Pool Salt Calculator

Introduction

A saltwater pool needs the right amount of salt to keep its chlorine generator running well. Too little salt and the system won't make enough chlorine. Too much salt can damage your equipment. This pool salt calculator tells you exactly how many pounds, kilograms, or 40-lb bags of salt to add based on your pool size, your current salt level, and your target salt level.

Each salt water chlorine generator has its own recommended salt level, usually printed in its manual. Hayward's AquaRite, for example, lists 2,700 to 3,400 ppm as ideal, with 3,200 ppm being optimal.¹ To use this tool, grab a salt test strip or digital salt meter and test your water first. Then enter your pool volume in gallons, type in your current reading, set your target level, and hit calculate. The calculator works through the math and shows each step so you can see how the formula works.

How to Use Our Pool Salt Calculator

Enter three simple values about your pool and this calculator will tell you exactly how many pounds, kilograms, and bags of salt you need to add.

Pool Volume: Enter the total size of your pool in gallons. If you don't know the exact number, pick one of the quick-select presets like Small (5,000 gal), Medium (10,000 gal), Large (20,000 gal), or XL (30,000 gal). You can type a number or drag the slider.

Current Salt Level: Enter the salt level your pool has right now in parts per million (ppm). You can find this number by using a salt test strip or a digital salt meter. If your salt chlorine generator has a digital display, it may show this reading too.

Target Salt Level: Enter the salt level you want your pool to reach in ppm. Check your owner's manual for the exact number your system needs.

Once all three fields are filled in, press Calculate to see your results. The calculator will show the pounds of salt to add, the weight in kilograms, and how many standard 40-lb bags to buy. A step-by-step breakdown and a bar chart will also appear so you can see exactly how the math works.

How to Calculate How Much Salt Your Pool Needs

A saltwater pool uses a device called a salt water generator (SWG) to turn dissolved salt into chlorine. This keeps your water clean and safe to swim in. For the SWG to work right, your pool water needs to have the correct amount of salt in it. Hayward's AquaRite manual puts the ideal level at 2,700 to 3,400 parts per million (ppm).¹ A low salt level reduces the generator's efficiency and chlorine production, and a high one can make the unit shut down and give the water a salty taste, generally at about 3,500 to 4,000 ppm.¹ Along with salt, keeping your water's pH level balanced is just as important for swimmer comfort and equipment longevity.

What This Pool Salt Calculator Does

This calculator tells you exactly how many pounds or kilograms of pool-grade salt to add to your water. You enter three numbers: your pool's volume in gallons, your current salt level in ppm, and your target salt level in ppm. The tool uses a standard dosage formula to figure out the right amount. It also tells you how many 40-lb bags of salt to buy so you don't have to do that math yourself.

How to Find Your Current Salt Level

You can test your pool's salt level with salt test strips, a digital salt meter, or a drop-based test kit. Many salt water generators also have a built-in salt reading on their control panel. Test your water before using this calculator so you get an accurate result.

How to Find Your Pool Volume

If you don't know your pool's volume, you can estimate it using the shape of your pool. A U.S. gallon is 231 cubic inches and a cubic foot is 1,728 cubic inches, so a cubic foot holds about 7.48 gallons.² For a rectangular pool, multiply the length, width, and average depth in feet, then multiply by 7.5 to get gallons. For a round pool, multiply the diameter by itself, then by the average depth, then by 5.9. Your pool builder or owner's manual may also list the volume. For a faster and more precise result, try our pool volume calculator, which handles rectangular, circular, and oval pool shapes automatically.

Tips for Adding Salt to Your Pool

Use sodium chloride salt that is more than 99% pure.¹ Do not use rock salt, iodized salt, or salt with anti-caking additives.¹ Add the salt with the pump running and brush it around so it does not pile up on the bottom. Run the pump for 24 hours so the salt spreads evenly, and retest before adding more.¹ Adding salt in small amounts is always safer than adding too much at once, because the only way to lower the salt level is to partly drain the pool and refill it with fresh water.¹

Formulas used

Salt to Add (lbs)

\text{Salt (lbs)} = V \times 8.34 \times \frac{T - C}{1{,}000{,}000}

Convert Pounds to Kilograms

\text{kg} = \frac{\text{Salt (lbs)}}{2.205}

Number of 40-lb Bags

\text{Bags} = \left\lceil \frac{\text{Salt (lbs)}}{40} \right\rceil

Frequently asked questions

What salt level should my pool be at?

Check your generator's owner's manual for the exact number your model needs. Hayward's AquaRite, for example, lists 2,700 to 3,400 ppm as ideal, with 3,200 ppm optimal.¹ The default target in this calculator is 3,200 ppm.

What happens if I add too much salt to my pool?

A high salt level can make the chlorine generator shut down, and salt generally starts to taste in the water at about 3,500 to 4,000 ppm.¹ The only way to lower the salt level is to partly drain the pool and refill it with fresh water.¹ There is no chemical you can add to remove salt.

Can I use table salt or rock salt in my pool?

No. Use sodium chloride that is more than 99% pure, such as salt sold for pools or water softeners. Do not use rock salt, iodized salt, or salt with anti-caking additives.¹ Both can cloud your water or damage your equipment.

How do I test my pool's salt level?

You can test your salt level with salt test strips, a digital salt meter, or a drop-based test kit. Many salt water generators also show the salt reading on their control panel. Test your water before using this calculator so you get an accurate result.

How long does it take for pool salt to dissolve?

Run the pump for 24 hours after adding salt so it spreads evenly through the pool; a generator's salt display may also take 24 hours to catch up.¹ Pour the salt into the shallow end and brush any piles that settle on the bottom. Wait a full day and retest your water before adding more salt.

What does ppm mean?

PPM stands for parts per million. It measures how much salt is dissolved in your water. For example, 3,200 ppm means there are 3,200 parts of salt for every one million parts of water.

How does the pool salt formula work?

The formula is: Salt (lbs) = Pool Volume (gal) × 8.34 × (Target ppm − Current ppm) ÷ 1,000,000. The number 8.34 is the weight of one gallon of water in pounds. The U.S. Geological Survey lists pure water at 60°F as weighing 62.366 pounds per cubic foot.³ A U.S. gallon is 231 cubic inches, so a gallon of water at that temperature weighs about 8.34 pounds. The formula finds the weight of salt needed to raise your pool's salinity from its current level to your target level.

What if my current salt level is higher than my target?

The calculator will tell you that no salt needs to be added. If your level is too high, the only way to lower it is to drain some pool water and replace it with fresh water. You cannot add a chemical to remove salt.

How many bags of salt does a typical pool need?

It depends on your pool size and how low your salt level is. A 10,000-gallon pool going from 0 to 3,200 ppm needs about 267 lbs, or roughly 7 bags of 40-lb salt. A pool that just needs a small boost may only need 1 or 2 bags.

Does rain or evaporation change my salt level?

Yes. Rain adds fresh water, and salt is lost mainly when water is added or drained, through splashing, backwashing, or draining after rain.¹ Salt is not lost to evaporation, so evaporation raises the concentration until the water is topped up. Retest your salt level after heavy rain or long dry spells.

How often should I check my pool's salt level?

Test your salt level at least once a month. Also test after heavy rain, after adding fresh water, or if your salt chlorine generator shows a low-salt warning. Regular testing helps keep your system running smoothly.

What is the difference between a saltwater pool and a regular chlorine pool?

Both use chlorine to keep water clean. A saltwater pool uses a salt chlorine generator to make its own chlorine from dissolved salt. A regular pool needs you to add chlorine by hand using liquid, tablets, or granules. Saltwater pools feel softer on skin and eyes.

Sources

AquaRite Electronic Chlorine Generator W3AQR15 W3AQR9 W3AQR3 Owner's Manual (092540 Rev G). Hayward Industries. Water Chemistry: Salt Level; Type of Salt to Use; How to Add or Remove Salt, p. 5. Accessed September 29, 2026.

NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement. National Institute of Standards and Technology. 2026;Units of Volume and Liquid Measure, p. C-6. Accessed September 29, 2026.

Water Density. Water Science School. U.S. Geological Survey. Accessed October 7, 2026.

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