Rectangle
A 32 × 16 ft pool that is 3.5 ft deep at one end and 6.5 ft at the other averages 5 ft deep. It holds 32 × 16 × 5 × 7.48052 = 19,150 gallons.
Salt Water Pool Salt Calculator
Exact bags for your chlorinator, before you buy or pour
Too little salt and the cell stops making chlorine. Too much, and fixing it means draining and refilling part of the pool.
Enter a water test and gallons to get the pounds and 40-lb bags at your salt system’s own manual target: Pentair, Jandy, Hayward, CircuPool or Intex.
No gallon figure? Measure the size in feet and inches. Typed a g/L reading as ppm? The calculator catches that before a single bag goes in.
Example result
Example: 15,000 gal at 2,400 ppm. Type your own numbers.
Add 75 pounds of salt to raise 15,000 gallons from 2,400 to 3,000 ppm.
- pounds
- 75
- 40-lb bags
- 2
- kilograms
- 34
SourceTarget 3,000 ppm from the Jandy AquaPure Installation and Operation Manual, §4.7. Every brand’s range is on the salt level chart by brand.
PanelJandy publishes no accuracy figure for its panel’s salt reading.
How to add this dose
Adding the salt takes 4 steps.
- Turn chlorine production off, the way your salt system’s manual describes.
- Broadcast 75 lb of salt (2 of the 40-lb bags) around the outer edge or into the shallow end, never through the skimmer, main drain or surge tank.
- Run the pump 24 hours so the salt dissolves completely.
- Retest with a separate test and the panel, then turn chlorine production back on.
Bag prices are on pool salt cost. The full sequence, with brushing and the salt to buy, is on how much salt to add to your pool.
Drag the ends to match your pool
Test 2,400Panel
Drag the markers to set your reading and target
- Salt in the water now
- Salt to add
- Salt above target
- Target
- Jandy range
By brand
Targets by brand: Pentair, Jandy, Hayward, CircuPool, Intex
Most pool guides call 3,200 ppm the ideal salt level, inside a 2,700 to 3,400 ppm range. Your salt system’s own manual sets its target, listed below. Pick your system and the calculator uses that figure.
A salt system, also called a salt chlorine generator or saltwater chlorinator, turns dissolved salt into chlorine inside its salt cell.
- Pentair3,600 or 3,400 ppm
- Jandy3,000 ppm
- Hayward3,200 ppm
- CircuPool3,500 ppm
- Intex3,000 ppm
For each system’s range, warning lights and source document, see the pool salt level chart.
No gallon figure
No gallon figure? Measure in feet and inches
Four measurements in feet give you the gallons: length, width, shallow-end depth and deep-end depth. For a round pool, one diameter replaces the length and width.
Measure length and width across the water surface. Measure each depth from the waterline down. Every box takes decimal feet or feet and inches, so 3.5, 3'6" and 3 ft 6 in all mean the same 3.5 ft.
For average depth, add the shallow and deep ends and halve the total. If your pool is one depth all over, put the same number in both boxes. A diving well that drops off in a short stretch isn’t a straight slope, so the two-end average overstates that pool’s volume.
Round or above-ground
A round pool, including an Intex above-ground pool, holds diameter² × average depth × 5.875 gallons. A 24 ft round pool averaging 5 ft deep holds about 16,921 gallons.
Salt scales with gallons, so a 10 percent volume error becomes a 10 percent dose error. The pool volume calculator handles oval pools too, shows each step and sends the gallons back here.
The math
How the pool salt calculator works
The math is a mass ratio. 1 ppm is 1 milligram of salt in every liter of water, so each gallon needs 0.0000083454 pounds of salt for every ppm you raise the level.
Pounds of salt = gallons × (target ppm − test ppm) × 0.0000083454. For bags, divide the pounds by 40 and round up to the next half bag.
- 1 gallon= 3.785411784 L
- 1 ppm= 1 mg/L = 0.001 g/L
- 1 pound= 453.59237 g
- 3.785411784 × 0.001 ÷ 453.59237= 0.0000083454 lb per gallon per ppm
- 83.45lbper 10,000 gallons for each 1,000 ppm
Worked example: the calculator’s default pool
15,000 gal × (3,000 − 2,400) ppm × 0.0000083454= 75.1 lb
75 pounds2 40-lb bags34 kilograms
Bags round up to the next half bag. Target 3,000 ppm is the Jandy AquaPure figure.
Worked example: a first fill
10,000 gal × (3,200 − 0) ppm × 0.0000083454= 267.1 lb
267 pounds7 40-lb bags
A new pool with no salt reads 0 ppm. Target 3,200 ppm is the Hayward AquaRite figure.
First-fill 40-lb bags by salt system
| Salt system target | 10,000 gal | 15,000 gal | 20,000 gal |
|---|---|---|---|
| Pentair3,600 ppm | 7.5 bags300 lb | 11.5 bags451 lb | 15.5 bags601 lb |
| Jandy3,000 ppm | 6.5 bags250 lb | 9.5 bags376 lb | 12.5 bags501 lb |
| Hayward3,200 ppm | 7 bags267 lb | 10 bags401 lb | 13.5 bags534 lb |
| CircuPool3,500 ppm | 7.5 bags292 lb | 11 bags438 lb | 15 bags584 lb |
| Intex3,000 ppm | 6.5 bags250 lb | 9.5 bags376 lb | 12.5 bags501 lb |
Every cell starts from 0 ppm and rounds up to the next half bag. Pentair’s guide also gives a second target, 3,400 ppm. That takes 7.5 bags for 10,000 gallons.
Low and high salt
Low salt adds, high salt drains
Low salt stops chlorine. High salt damages equipment. You fix low salt by adding more. For high salt, the manuals we reviewed say to drain part of the water and refill. The calculator handles both: pounds and bags when you’re low, gallons to drain when you’re high.
Too little salt
The cell makes less chlorine, then none. A Pentair IntelliChlor runs at reduced output below 2,800 ppm and shuts off below 2,600 ppm. Jandy warns that salt below 2,000 ppm causes premature salt cell failure. Add salt to fix it. The calculator above gives the pounds.
Too much salt
No chemical takes salt out. In the manuals we reviewed, the fix is draining part of the water and refilling with fresh. Jandy gives two thresholds: above 4,000 ppm the power center may be damaged, and above 6,000 ppm pool fixtures may corrode. The calculator tells you how many gallons to drain. For the inches per stage, see the staged plan on how to lower the salt level in your pool.
The drain figure assumes your refill water has no salt in it. Test the refill water first, then drain in stages and retest each time.
To fix low salt, turn chlorine production off, broadcast the salt, brush the floor, run the pump 24 hours and retest. The full sequence from the Pentair and Jandy manuals is on how much salt to add.
Owner questions
Pool salt calculator FAQ
Every answer quotes a manual, works a figure from the calculator’s constants, or says what we haven’t checked.
How many 40-lb bags does a 10,000-gallon pool need?
Starting from 0 ppm, a 10,000-gallon pool needs 6.5 bags at Jandy (3,000 ppm) or Intex (3,000 ppm); 7 bags at Hayward (3,200 ppm); 7.5 bags at Pentair (3,600 or 3,400 ppm) or CircuPool (3,500 ppm). Bags round up to the next half bag. If your pool already has salt, you only need the gap between your test reading and the target. The calculator works that out from your gallons and test.
Does salt evaporate?
No. Salt leaves a pool only through splash-out, backwash or draining, per Hayward’s AquaRite S3 owner’s manual. We haven’t checked the other brands’ documents for the same statement. The calculator doses from your test reading, so any salt you’ve lost shows up as the gap to the target.
Does this work for an Intex above-ground pool?
Yes. Pick Intex Krystal Clear and the target fills in at Intex’s 3,000 ppm (range 2,500–3,500 ppm, from the Intex saltwater system specification sheet). A round pool holds diameter² × average depth × 5.875 gallons, so choose Round under “Don’t know the gallons?” and enter the diameter and depth.
How do you convert pool salt units?
One ppm is one milligram of salt per liter, so 1,000 ppm is one gram per liter (g/L). One pound is 0.454 kilograms. A Jandy AquaPure panel reading of 3.0 g/L means 3,000 ppm. Enter a test reading under 100 ppm, such as 3.2, and the calculator holds the dose until you confirm it isn’t g/L. For strip, drop-kit and meter steps, see how to test the salt level in your pool.