Salt chlorine generators need the salt level within a set range, usually 2,700–3,400 ppm with an ideal of about 3,200 ppm. Too little and the cell cannot make enough chlorine; too much can corrode equipment. Add pool-grade salt with the pump running and retest after 24 hours.
How to use the Pool Salt Calculator
- Pool volume
- Current salt level
- Target salt level
- Salt bag size
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the pool volume, your current salt reading and the target level for your chlorinator.
Inputs explained
| Field | What to enter |
|---|---|
| Pool volume | Units: US gal, L, UK gal |
| Current salt level | In ppm |
| Target salt level | In ppm |
| Salt bag size | Choose one: 40 lb, 50 lb, 25 kg, 20 kg |
What each result means
- Salt to add = max([Target salt level] – [Current salt level], 0)×[Pool volume]×1000÷1000000
- Bags of salt = ceil([Salt to add]÷[Salt bag size] – 0.000001)
Example values
How the main result changes when Pool volume changes and everything else stays at the example values above:
| Pool volume (US gal) | Salt to add (lb) |
|---|---|
| 7,500 | 50.1 |
| 11,250 | 75.1 |
| 15,000 | 100.1 |
| 18,750 | 125.2 |
| 22,500 | 150.2 |
| 30,000 | 200.3 |
Formula
Salt to add (lb) = gallons × 8.34 × (target − current ppm) ÷ 1,000,000
If too high: water to replace = volume × (1 − target ÷ current)
Worked example
Inputs: Pool volume: 15,000 US gal; Current salt level: 2,400 ppm; Target salt level: 3,200 ppm; Salt bag size: 40 lb.
Results: Salt to add = 100.1 lb; Bags of salt = 3; Water to drain and refill (if too salty) = 0 US gal.
Frequently asked questions
How much salt does a pool need?
About 30 lb per 1,000 gallons to raise from 0 to 3,600 ppm; to raise 800 ppm in a 15,000 gal pool, about 100 lb.
What salt level should a saltwater pool have?
Usually 2,700–3,400 ppm; check your chlorinator's manual (many recommend 3,200 ppm).
How do I lower salt in a pool?
Drain part of the water and refill with fresh water.