Pool chlorine calculator

How much liquid chlorine or bleach to add to reach your target free chlorine.

Pool volume

gal liters m³

Chlorine strength on the label 6% (household bleach) 8.25% (concentrated bleach) 10% (pool liquid chlorine) 12.5% (pool liquid chlorine)

Current free chlorine (ppm)

Target free chlorine (ppm)

Stabilizer / CYA (optional, ppm)

— Pour in front of a return jet with the pump running, ideally in the evening.

Free chlorine targets by stabilizer (CYA)

Stabilizer protects chlorine from sunlight but also weakens it, so the right chlorine level depends on your CYA.

CYA (ppm)	Minimum FC	Target FC	Shock (SLAM) FC
30	2	4–6	12
40	3	5–7	16
50	4	6–8	20
60	5	7–9	24
70	5	8–10	28
80	6	9–11	31

Saltwater pools can run lower: about 4.5% of CYA as a minimum.

How the dose is calculated

Liquid chlorine strength is sold as "trade percent": a gallon of 10% chlorine contains enough chlorine to raise 10,000 gallons by about 10 ppm. That works out to about 12.8 fl oz of 10% liquid chlorine, or 21 fl oz of 6% bleach, per ppm in 10,000 gallons. Bleach loses strength as it ages, so old jugs need a little more.

Want pH, alkalinity and calcium too?

Poolmind for iPhone does this math for every chemical: acid and soda ash for pH (based on your alkalinity and temperature), baking soda, calcium chloride, stabilizer and salt — plus a test log, charts and water balance (CSI).