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Chlorine Dilution Calculator
This easy-to-use calculator tells you how much bleach product to dilute with water to get your desired concentration (ppm) of chlorine solution. It is intended for use by public health units, health care facilities, child care centres, swimming pool operators, and the general public (e.g., for disinfection of wells and homes).
Important: Always add the bleach solution to the water when preparing the solution, not vice versa.

Concentration of bleach product
Please check the label on bottle for the exact percentage. Typical household bleach is 5.25%, and typical industrial bleach is 12%.
% sodium hypochlorite
Desired volume of chlorine solution
Desired concentration of chlorine solution
ppm or mg/L
Desired unit of measure for bleach product
Select your preferred unit of measure for the amount of bleach to add to water.
The desired concentration of chlorine solution is higher than your bleach concentration. Calculation results cannot be displayed. Adjust your values to see results.

To make your chlorine solution add {{bleachVolumeResult}} of bleach to {{waterValResult| number:2}} {{finalSolVolUnitText()}} of water.

Dilution of bleach to water ratio is 1:{{diluteRatio}}.

View Assumptions

Assuming {{initialConValue| number:2}}% sodium hypochlorite is used, this is equivalent to {{equivBleachConc| number:2}}% available chlorine. Available chlorine is the amount of chlorine available for disinfection.
1 drop ≈ 0.05 ml
1 teaspoon ≈ 5ml
1 cup ≈ 250 ml
1 tablespoon ≈ 15 ml

Back to Results
Your results will appear here.

  • Always follow safety precautions and the manufacturer's directions when working with concentrated solutions of bleach (sodium hypochlorite). To avoid injury, use appropriate personal protective equipment during handling (read the label and refer to the material safety data sheet).
  • Chlorine bleach solution might damage some surfaces (e.g., metals, some plastics) so it is advisable to check with the manufacturer before using.
  • For chlorine bleach solution to be effective, a certain amount of contact time with the surface is needed. Contact time varies according to what is being disinfected.
  • Never mix ammonia products with bleach or bleach-containing products. This practice produces chlorine gas - a very toxic gas that can cause severe breathing problems, choking and potentially death.
  • To be more effective, clean the surface before using the chlorine bleach solution.
  • A bottle of bleach has a shelf life, so check the bottle for an expiry date or check with the manufacturer for the shelf life of the product.
  • Do not premix the water and bleach solution, as it loses potency over time.
The calculation performed in this tool is based on the following equation: C1 x V1 = C2 x V2
  • C1 is the initial concentration of the bleach (sodium hypochlorite) solution.
  • V1 is the volume of the bleach to be diluted with water. This is what you are trying to calculate.
  • C2 is the concentration of the diluted bleach solution you are preparing.
  • V2 is the volume of bleach solution you are preparing.


If you have any questions or ideas on how to improve this calculator please contact Public Health Ontario’s Environmental and Occupational Health team at​​​​​​


The dilution calculator is provided/being made available by Public Health Ontario without any warranties, express or implied, including fitness for a particular purpose. Public Health Ontario, its directors, employees and agents shall not be liable or responsible to any person for any harm, loss or damage that may arise in any connection with the use of the dilution calculator, including without limitation any direct, indirect, special, third party, or consequential damages. ​​


If you are a well contractor, please make sure to use the Well Disinfection Tool.

Uncontrolled print copy. Valid only on day of Print: [date]
Page updated on [date/time] 2015-10-02 12:41 PM
© , Ontario Agency for Health Protection and Promotion