Pool Chlorine Dose Calculator

Work out pool chlorine dose instantly with clear inputs, formula shown and shareable results.

About Pool Chlorine Dose Calculator

One part per million in a cubic metre of water is one gram, so the chlorine needed is the ppm increase times the volume in cubic metres. Dividing by the product's available chlorine percentage gives the actual product weight — 65% dichlor needs about 1.5 times the calculated chlorine mass.

Formula

Chlorine dose

chlorine (g) = ppm increase x volume (m3); product = chlorine / available chlorine fraction

Worked example

With the default values below, Pool Chlorine Dose Calculator returns Product required of 132. Change any input above and every figure here is recalculated in your browser.

Inputs used

Pool volume: 45 m³
Current free chlorine: 0.6 ppm
Target free chlorine: 2.5 ppm
Product available chlorine: 65 %

Results

Product required: 132 g
Chlorine to add: 86 g
Increase required: 1.90 ppm
Shock dose to 10 ppm: 651 g

Step by step

1Values used
2Chlorine dose
3Product required= 132 g
4Chlorine to add= 86 g
5Increase required= 1.90 ppm
6Shock dose to 10 ppm= 651 g

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is ppm the same as grams per cubic metre?

Because a cubic metre of water is 1,000 kg. One gram in 1,000,000 grams is one part per million exactly.

What is shocking?

Raising free chlorine to 10 ppm or more to break down combined chloramines. It is done at dusk since sunlight destroys chlorine rapidly.