Pool Salt Calculator
Your estimate
- Water to drain
- 0%
Pounds of salt and bags to reach your salt cell’s target level.
Updated 2026-10-20 · Based on: exact volume formulas (1 US gal = 3.785 L) and chemical strengths (1 ppm = 1 mg/L).
How to use the Pool Salt Calculator
- Enter the pool volume in gallons (use the pool volume calculator if you do not know it).
- Test the water and enter the current salt level in ppm (0 for a new fill).
- Enter the target from your salt cell’s manual — usually 3,200 ppm (range 2,700–3,400).
- Read the salt to add and the number of 40 lb bags.
Formula
Salt (lb) = gallons × (target ppm − current ppm) × 8.34 ÷ 1,000,000 — 8.34 lb is the weight of a gallon of water.
Metric: salt (kg) = litres × ppm rise ÷ 1,000,000. If the water is too salty, only dilution helps: drain (current − target) ÷ current of the water and refill.
Worked example
With the values preset in the calculator above:
- Pool volume
- 15,000 gallon
- Current salt level
- 0 ppm
- Target salt level
- 3,200 ppm
- Salt bag size
- 40 lb
- Salt to add
- 401 lb (182 kg)
- Bags
- 11
- Water to drain
- 0%
Pool salt chart
- 10,000 gal from 0 to 3,200 ppm: 267 lb (7 bags).
- 15,000 gal from 0 to 3,200 ppm: 401 lb (11 bags).
- 20,000 gal from 0 to 3,200 ppm: 534 lb (14 bags).
- 20,000 gal from 2,500 to 3,200 ppm: 117 lb.
How to add salt to a pool
- Use pool salt that is at least 99 % pure sodium chloride, without anti-caking agents or iodine.
- Turn the salt cell off, run the pump and pour the salt around the shallow end, away from the skimmer.
- Brush it toward the main drain until it dissolves, then circulate for 24 hours before turning the cell back on and retesting.
- Add it in two steps when you are not sure of the volume — it is easy to add more and hard to take it out.
Salt for a new fill (0 → 3,200 ppm)
| Pool volume | Salt to add | Bags |
|---|---|---|
| 5,000 | 134 lb | 4 |
| 10,000 | 267 lb | 7 |
| 15,000 | 401 lb | 11 |
| 20,000 | 534 lb | 14 |
| 25,000 | 668 lb | 17 |
| 30,000 | 801 lb | 21 |
Frequently asked questions
How much salt do I need for a 10,000 gallon pool?
From fresh water to 3,200 ppm: 267 lb, or 7 bags of 40 lb.
How much salt to raise 500 ppm?
About 41.7 lb per 10,000 gallons (41.7 lb).
What if I add too much salt?
Salt does not evaporate. Partly drain and refill: going from 4,000 to 3,200 ppm means replacing 20% of the water.
How often do I add salt?
Only after rain, splash-out, backwashing or draining — salt is not used up by the cell. Test monthly.
More calculators
Estimates only — check quantities with your supplier and local building code before you order.