Chlorine Dosage Calculator
How much chlorine to add to reach a safe, swimmable level — from your pool volume, current reading, and the strength printed on your product.
Add about
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Estimate only — always follow the dosing instructions on the product packaging and never mix chemicals.
Track it automatically with Algae Later →What level should chlorine be?
Aim for 1–3 ppmfree chlorine (a target of ~2 ppm). Below 1 ppm the water isn't protected and algae takes hold; well above 3 ppm it's harsh on eyes and skin. The dose you need scales with your pool volume and how far below target you are.
Frequently asked
- How much chlorine raises 1 ppm?
- It depends on the product. Granular cal-hypo (~65%) takes roughly 1.5 g per m³ (per 1,000 L) to raise free chlorine by about 1 ppm. Enter your product's own figure above for accuracy.
- My chlorine is too high — what now?
- You can't easily remove chlorine; stop dosing and let sunlight and time bring it down before swimming. Re-test rather than adding more.
- How often should I test?
- Test free chlorine and pH every 2–3 days, and sooner after heavy use, parties, heat waves or heavy rain.