Chlorine Dosage Calculator
Disinfecting a well, a storage tank, or emergency drinking water? The dose depends on volume and target PPM — 50 PPM for shock-chlorinating a well is very different from 2 PPM for a pool. Enter both, get grams.
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Chlorine Dosage Calculator
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Disinfecting a well, a storage tank, or emergency drinking water? The dose depends on volume and target PPM — 50 PPM for shock-chlorinating a well is very different from 2 PPM for a pool. Enter both, get grams.
How to use this calculator
- Enter water volume in liters.
- Enter target PPM (2 for pools, 50 for well shock).
- Get grams of chlorine.
- Wait the recommended contact time, then re-test.
The formula
Grams = target PPM × liters ÷ 1,000 (before product-strength adjustment).
What the inputs mean
The target is the concentration you want, in PPM. The volume is how much liquid you are treating. The result tells you exactly how much chlorine to add.
Worked example
Shock-chlorinating a 5,000 L well at 50 PPM: 50 × 5,000 ÷ 1,000 = 250 g chlorine.
Quick reference
| Volume | Chlorine for 50 PPM |
|---|---|
| 1,000 L | 50 g |
| 5,000 L | 250 g |
| 10,000 L | 500 g |
Adjust for product strength (e.g., 65% calcium hypochlorite).
Where you will actually use this
Underdosing leaves pathogens alive; overdosing makes water unusable. Precision matters.
- Well shock chlorination
- Water tank disinfection
- Emergency water treatment
- Pool startup
Mistakes that give wrong answers
- Wrong contact time (dose without time does not disinfect)
- Not adjusting for product strength
Key takeaways
- Formula: Chlorine (g) = Target PPM × Water volume (L) ÷ 1,000
- Remember: Adjust for product strength (e.g., 65% calcium hypochlorite).
- Watch out for: Wrong contact time (dose without time does not disinfect)
- Next step: run your own numbers in the calculator above, then verify with a measurement — calculated values are only as good as the inputs.
Frequently asked questions
What PPM for shock chlorinating a well?
Typically 50–200 PPM with adequate contact time.
How long before using the water?
Until chlorine falls to safe levels and bacteria tests pass — often 12–24 hours.