Saltwater Pool Salt Calculator
Find how much salt to add to a saltwater pool. Enter the pool size and your current and target salt levels to get the pounds of pool salt, number of bags, and cost to reach the target — with a dosing table and a downloadable PDF report.
| Target | Change | Salt (lb) | Bags |
|---|---|---|---|
| Enter your pool to see targets | |||
| Bags added | Salt (lb) | Resulting ppm | Status |
|---|---|---|---|
| Enter your pool to see the dosing steps | |||
How to use the saltwater pool salt calculator
Four quick steps turn your pool size and salt readings into the pounds of salt to add, the number of bags, the cost, and a stage-by-stage dosing table — with a downloadable report.
Enter pool size
Pick the shape and enter length, width, and average depth. That sets the pool volume in gallons.
Enter salt levels
Give your current salt reading and pick the target your generator wants. The gap drives the dose.
Set salt & cost
Choose the bag size and price. You get pounds, bags, and cost to reach the target.
Read results & save a PDF
See the dose, a per-target table, and a dosing progression — then download a report for the pool shed.
How the salt dose is calculated
Volume comes from the shape and depth; the dose is driven by the gap between your current and target ppm, converted to pounds of salt. Here is the exact math the calculator runs.
Worked example — 32 × 16 ft rectangle, 5 ft average depth, 0 → 3,200 ppm, 40-lb bags at $10
Volume: 32 × 16 × 5 × 7.48 ≈ 19,148 gal
Salt: 19,148 × 3,200 × 8.34 / 1,000,000 ≈ 511 lb
Bags: ceil(511 / 40) = 13 bags → 13 × $10 = $130
Each bag adds: 40 / (19,148 × 8.34 / 1,000,000) ≈ 250 ppm
≈ 511 lb · 13 bags · $130 to reach 3,200 ppm. Add in stages and retest.
Salt dosing reference charts
Handy lookups for generator targets, salt to raise 1,000 ppm by pool size, and a fresh-fill guide. Always add in stages and retest before topping up.
| Brand | Typical target | Working range |
|---|---|---|
| Jandy | ~3,000 ppm | 2,700–3,400 |
| Hayward | ~3,200 ppm | 2,700–3,400 |
| Pentair | ~3,400 ppm | 2,800–4,000 |
Always confirm your unit’s exact range in its manual and aim for the middle. Too low stops chlorine; too high risks corrosion.
| Pool volume | Salt for +1,000 ppm | 40-lb bags |
|---|---|---|
| 10,000 gal | ~83 lb | 3 bags |
| 15,000 gal | ~125 lb | 4 bags |
| 20,000 gal | ~167 lb | 5 bags |
| 25,000 gal | ~209 lb | 6 bags |
| 30,000 gal | ~250 lb | 7 bags |
Scale linearly: to raise 2,000 ppm, double it. Only dose for the gap between your current and target reading.
| Pool volume | Salt needed | 40-lb bags |
|---|---|---|
| 10,000 gal | ~267 lb | 7 bags |
| 15,000 gal | ~400 lb | 10 bags |
| 20,000 gal | ~534 lb | 14 bags |
| 25,000 gal | ~667 lb | 17 bags |
| 30,000 gal | ~801 lb | 21 bags |
Bags rounded up. An established pool only loses salt to splash-out and backwashing, so it needs far less top-off each year.
Everything the calculator works out
A pool size and two readings give you the exact dose, the bags to buy, and a safe way to get there in stages.
Key figures behind the dose
Built for dialing in salt
From a brand-new fill to a mid-season top-off, the same calculator turns pool size and readings into an exact, safe dose.
Just filled a saltwater pool and needs to bring it from zero up to the generator’s target.
- Enter shape & dimensions
- Set current 0, pick target
- Add in stages, retest
Opening the pool and topping up salt lost to splash-out and backwashing over the year.
- Enter your current reading
- Dose only for the gap
- Often just a bag or two
Added too much and needs to know how much water to drain and refill to get back in range.
- Enter the high reading
- See the drain percentage
- Refill fresh, then retest
7 tips for salting a pool safely
Salt is easy to add and hard to remove, so the whole game is going slow and testing. These points keep you in range.
Saltwater pool salt calculator FAQ
The dosing, level, and safety questions people ask most when salting a pool.
Find the pool volume, then salt = gallons × (target − current) × 8.34 ÷ 1,000,000.
Example: a 32 × 16 ft pool at 5 ft average holds ~19,100 gal. Raising 0 → 3,200 ppm needs ≈ 510 lb, about 13 forty-pound bags.
Add in stages, run the pump 24 hours, and retest before the last bag or two — you can add more, but the only way to lower an over-salted pool is to drain and refill.
Dosing works from the change you want: lb = gallons × (target − current) × 8.34 ÷ 1,000,000, where 8.34 is the weight of a gallon of water.
The (target − current) part matters: if the pool reads 2,800 and you want 3,200, dose for the 400 ppm gap, not the full 3,200 — doing the full amount is a classic over-salting mistake.
Then divide the pounds by your bag size (usually 40 lb) and round up.
Volume depends on shape, always times average depth and 7.48 gallons per cubic foot.
Rectangle: L × W × depth × 7.48. Oval: L × W × depth × 7.48 × 0.785. Round: diameter² × depth × 7.48 × 0.785. Average depth is (shallow + deep) ÷ 2.
A 32 × 16 ft rectangle at 5 ft average is ~19,100 gal. If you already know your gallons from the builder, use that instead.
Most salt chlorine generators run best between about 2,700 and 3,400 ppm, and each brand has its own ideal target — Jandy ~3,000, Hayward ~3,200, Pentair ~3,400.
Check your generator’s manual and aim for the middle of its range — a cushion above the low-salt cutoff without risking corrosion at the high end.
Too low and the cell won’t make chlorine; too high can mean salty taste, scaling, corrosion, or a high-salt shutoff.
Use pool-grade salt that’s at least 99% pure sodium chloride (NaCl), sold specifically for pools. It dissolves cleanly and won’t stain or clog the cell.
Avoid rock salt, salt with anti-caking agents or iodine, and water-softener salt — impurities and additives can harm the generator or discolor the water. Finer evaporated pool salt dissolves fastest.
It usually comes in 40-lb bags (sometimes 50); the higher the purity, the fewer problems down the line.
Over-salting can’t be reversed with a chemical — the only fix is to drain part of the water and refill with fresh, diluting the salt back down.
Beyond wasting water, high salt can give a salty taste, promote scaling, corrode metal fixtures and equipment over time, and trip a high-salt shutoff that stops chlorine production.
That’s why you add gradually — about three-quarters of the dose first, circulate a day, retest, then top up. It’s always easier to add than remove.
Plan on about 24 hours with the pump running before the salt is fully dissolved and evenly mixed enough for an accurate reading.
Broadcast the salt across the pool rather than dumping it in one spot, brush any that settles, and keep the pump circulating. Don’t run the salt cell until it’s dissolved.
Retesting too soon reads falsely low, tempting you to over-add — wait the full day before you test and decide on the last bag.
Salt is inexpensive — a 40-lb bag typically runs $8–$12, and the cost is simply bags × price.
Filling a fresh 20,000-gallon pool to ~3,200 ppm takes roughly 13 bags, about $100–$160. Topping off a pool only a few hundred ppm low might be just a bag or two.
Since salt only leaves through splash-out, backwashing, and dilution — not evaporation — an established pool needs only a little top-off each season.
Estimate only — add in stages and retest. Figures use US units (gallons, ppm, pounds). Use pool-grade salt that is at least 99% pure sodium chloride. Add roughly three-quarters of the calculated dose, run the pump about 24 hours to dissolve and mix it, then retest with a strip or meter before adding more — over-salting can only be corrected by draining and refilling. Volume is estimated from your dimensions and average depth, so an accurate reading depends on your actual gallons. Always follow your salt generator’s recommended range and instructions. For planning purposes only.