Pool Salt Calculator

Need to know how much salt to add to your pool? This calculator gives you the exact amount—in pounds or kilograms—so you can stop guessing and start swimming.

Whether you're setting up a new saltwater system, topping off after a week of rain, or trying to clear that annoying "low salt" warning on your chlorinator, just plug in your numbers and you'll know exactly how many bags to grab from the store. The calculator handles both liters and gallons, so it works no matter how your pool was measured.

Saltwater pools have become popular for good reason—they're gentler on your eyes and skin, and you never have to handle those chlorine tablets again. The tradeoff? You need to keep the salt level in the right range for the chlorinator to do its job. Too low and chlorine production drops off. Too high and you risk that unpleasant ocean taste or, worse, equipment damage down the road.

This calculator takes the math out of it so you can spend less time with a calculator and more time in the water.

Step 1: Enter Your Pool Volume

Type in your pool's water volume in liters. Don't worry if you only know gallons—the calculator shows the gallon equivalent in your results so you can double-check you entered it right.

Not sure of your pool volume? Check the paperwork from when your pool was built, or look for a sticker on your equipment. If you need to calculate it yourself: Length × Width × Average Depth × 7.5 gives you gallons for a rectangular pool. (For freeform or kidney-shaped pools, your best bet is usually the original documentation.)

Step 2: Enter Your Current Salt Level

This is your pool's current salt concentration in parts per million (ppm). You can get this number from a salt test strip, a digital salt meter, or the display on your chlorinator itself.

Starting with a fresh fill from the garden hose? You can enter 0, though most tap water actually has 200-400 ppm of naturally occurring minerals that read as salt.

Step 3: Enter Your Target Salt Level

This is where you want to end up. For most saltwater chlorinators, that's 3,200 ppm—but check your specific unit's requirements. (I've got a table below with recommendations by brand.)

Step 4: Get Your Results

Hit calculate and you'll see:

• Amount of salt to add in kilograms
• The ppm increase you're making
• Your pool volume in gallons for easy reference

Write down the number, head to the store, and you're set.

Most salt chlorinators run best between 2,700 and 3,400 ppm, with 3,200 ppm being the sweet spot. But here's something a lot of pool owners learn the hard way: different brands want different levels.

Why does this matter? Drop below your chlorinator's minimum and you'll get a "low salt" error—plus your chlorine production tanks and your pool won't stay clean. Go too far above the max and you're wasting salt while slowly wearing out the chlorinator cell.

Dig out your owner's manual for the exact numbers. Lost it? Just search your model number online—every manufacturer posts specs on their site.

One more thing about testing: Salt test strips and handheld meters can easily be off by 200-300 ppm. If your test strip says one thing and your chlorinator's display says another, trust the chlorinator. Its sensor is calibrated specifically for that unit. When in doubt, aim for the middle of your range rather than the edges—that gives you a buffer either way.

The short answer: pool salt or solar salt. Both are high-purity sodium chloride (99%+ pure) with no additives that could cause problems.

Here's a money-saving secret most pool stores won't tell you: pool salt is just solar salt in different packaging. I've bought the same 40-lb bags at Home Depot for $6 that pool stores sell for $11 with a "pool salt" label slapped on. Your chlorinator genuinely cannot tell the difference.

Look for bags labeled "solar salt," "water softener salt," or "extra coarse salt" at any big-box store or warehouse club. As long as it says 99% pure sodium chloride with no additives, you're good.

What to avoid:

Quick tip on dissolving: The coarser crystals actually work better than fine salt. They dissolve more slowly, which prevents concentrated piles from sitting on your pool floor and potentially damaging the finish.

For those times when you just want a quick answer without plugging in numbers, here's a cheat sheet. These assume you're targeting 3,200 ppm.

Salt Needed by Pool Size (Pounds)

Salt Needed by Pool Size (Kilograms)

The quick rule: For every 1,000 gallons, you need about 8.3 pounds of salt to raise the level by 1,000 ppm. Easy to remember, close enough for a ballpark.

Want to understand the math? Here's what's happening under the hood:

The formula:

```
Salt (lbs) = (Target ppm − Current ppm) × Pool Gallons × 8.34 ÷ 1,000,000
```

The 8.34 is the weight of a gallon of water in pounds. Dividing by a million converts parts per million into something usable.

Even simpler version:

```
Salt (lbs) = (ppm increase) × (gallons) ÷ 120,000
```

Let's walk through an example:

• Pool: 15,000 gallons
• Current: 2,400 ppm
• Target: 3,200 ppm
• Increase needed: 800 ppm

Salt = 800 × 15,000 ÷ 120,000 = 100 pounds

That's two and a half 40-lb bags—easy trip to the hardware store.

You definitely don't need to memorize this. That's the whole point of the calculator. But now you know it's not magic, and you can sanity-check your results if a number ever looks off.

After seeing the same questions pop up in pool forums year after year, I can tell you these five mistakes cause most of the headaches:

Mistake #1: Dumping all the salt in one spot

Salt is heavy—it sinks straight to the bottom. If you pour it all in one place, you end up with a concentrated pile that takes forever to dissolve and can actually damage your pool liner or plaster finish.

Instead, walk around the pool's perimeter and broadcast the salt across the water, focusing on the deep end. Turn your pump on to help circulation. The salt will dissolve much faster and you won't risk any damage.

Mistake #2: Testing too soon

This one catches almost everyone at least once. You add salt, wait an hour, test again... and it still reads low. So you add more. Then a day later your level is way too high.

Salt needs time to dissolve and circulate through the entire pool. Wait at least 24 hours—48 is better—with the pump running before you retest. Otherwise your reading will be artificially low because the salt hasn't mixed evenly yet.

Mistake #3: Using the wrong pool volume

A lot of people use the "standard" size for their pool type, but actual volumes vary quite a bit depending on depth changes, slopes, and irregular shapes. If your calculations consistently seem off—you add what the calculator says but the level never hits target—your volume estimate might be wrong.

Check your original pool paperwork or have it measured properly. The difference between "about 15,000 gallons" and your actual 18,000 gallons adds up fast.

Mistake #4: Wondering why you keep adding salt

Some pool owners worry something's wrong because they're adding salt every few weeks. Usually nothing's wrong—you're just learning how salt leaves your pool.

Salt doesn't evaporate with the water, but it does leave through splash-out (especially with kids), backwashing your filter, and draining water after heavy storms. This is normal maintenance, not a sign of a problem.

Mistake #5: Ignoring what the chlorinator says

If your test strip reads 3,100 ppm but your chlorinator is flashing "low salt," trust the chlorinator. Its sensor is calibrated specifically for that unit. Add salt until the error clears, regardless of what your handheld tester says.