Free tool · Calculator

Chlorination dose calculator

Estimate the quantity of product to dose a known water volume to a target free-chlorine concentration. A planning aid only, the real dose, contact time and neutralisation belong in a competent person's method statement.

Safety, read first

Shock chlorination is hazardous. Never mix chlorine with acids or other chemicals. Carry it out only under a COSHH assessment and method statement by a competent person. The system must be neutralised and flushed before being returned to use. These figures are illustrative and do not set your dose or contact time.

Water volume

litres

Target free-chlorine concentrationIn mg/l, which is the same as ppm.

mg/l

Product available-chlorine strengthRead it off the product label or safety data sheet.

A planning aid, not a substitute for a competent, site-specific method statement. Source: HSE, HSG274 Part 2 (2024), ‘Cleaning and disinfection’, p.87.

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"Chlorination dose calculator (Legionella)." Legionella.io. https://legionella.io/tools/chlorination-dose-calculator/

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