What is the difference between percentage and parts per million?

Both express concentration. One percent is equivalent to ten thousand parts per million, so 0.1% is equivalent to 1000 ppm. Use the units specified by your cleaning and disinfecting policy.

How much bleach should be mixed with water to disinfect?

It depends on the desired concentration. For general surface cleaning about 1000ppm is required which corresponds to a mixing ratio of approximately 1:60 starting from normal 6% bleach solution. Lower concentrations between 100 and 200 ppm are used for surfaces that come into contact with food, while concentrations around 5000 ppm corresponding to a ratio of about 1:10 is required for cleaning blood or body fluid contamination.

Can I use bleach with a concentration of 8.25%?

Yes. If you enter the original concentration of 8.25, then the calculator will adjust accordingly. The higher the bleach concentration is, the less bleach and more water it takes to achieve the same target concentration.

How long is diluted bleach effective?

Not for very long. Diluted bleach loses its disinfecting power after about 24 hours, so you should only prepare the amount that you will need and mix it fresh daily.

What substances must you never mix with bleach?

Never mix bleach with ammonia, acids such as vinegar or lemon juice, or other cleaning products. These combinations create toxic chlorine and chloramine gases. Always add the bleach to water first and work in a well-ventilated area.

Bleach Dilution Calculator

Your bleach and target

How do you want to set the dilution?

By target concentration

By dilution ratio (1:x)

Enter your stock bleach strength and the target strength you need. The calculator solves the bleach volume with C₁V₁ = C₂V₂.

Stock bleach concentration

Target measured in

Percent (%)

ppm

Target concentration

Final solution volume

Never mix bleach with ammonia, vinegar, or other acids. The reaction releases toxic chlorine gas. Always add bleach to the water, work in a ventilated area, and wear gloves and eye protection.

Your mixing recipe

Bleach to add (mL)

Water to add (mL)

Add 16.67 ml of bleach to 983.33 ml of water to make 1000 ml of solution at about 1000 ppm (0.1 percent) available chlorine.

Mix only what you need and use diluted bleach the same day. Its disinfecting strength fades within about 24 hours.

Bleach needed

Water needed: ml
Resulting strength (%)
Available chlorine (ppm)

Equivalent ratio (1 : n parts water)

Visuals and reference

Show the bleach-to-water split

A pie of how the final solution divides into bleach and water.

Show household measures

Convert the amounts to teaspoons, tablespoons, and cups.

Show common dilution targets

A table of bleach amounts for standard disinfection strengths.

How the solution divides

The share of the final volume that is bleach versus water.

Bleach and water in common household measures (approximate)
Measure	Bleach	Water
Milliliters (mL)	16.67	983.33
Teaspoons	3.38	199.5
Tablespoons	1.13	66.5
Cups	0.07	4.16
Fluid ounces	0.56	33.25

The bleach dilution calculator shows how much bleach and water to mix together to achieve the desired concentration. By entering the concentration of the concentrated bleach and the target concentration, it will show you the volume of bleach, the volume of water, and the final concentration in percent and ppm.

Features of the calculation tool:

Concentrated bleach is too strong for most cleaning and disinfecting tasks and must be diluted with water to achieve a safe and effective concentration. This tool can be used in two ways:

You can set the target concentration in percent or ppm and calculate the required amount of bleach to use. Alternatively you can specify a simple bleach-to-water mixing ratio such as 1:10 and then divide the final volume accordingly.

Dilution calculation equation:

In the concentration mode, the standard dilution equation is used where C stands for Concentration and V stands for Volume. The total amount of active chlorine before and after mixing remains the same.

C_1 V_1 = C_2 V_2

In this case, C1 is the concentration of the starting bleach, C2 is the target concentration, V2 is the final volume required and V1 is the amount of bleach required. After simplifying the formula, we get the following:

V_1 = V_2 \times \dfrac{C_2}{C_1}

Suppose you have a bleach with 6% concentration and want to make a solution of 2 liters at 1000ppm. Since 1000ppm is the same as 0.1%, then:

V_1 = 2000\ \text{mL} \times \dfrac{0.1}{6} \approx 33.3\ \text{mL}

Add about 33 milliliters of bleach and add water to make a total volume of two liters. The amount of water will be approximately 1,967 milliliters in total.

Percentages and PPMs

The concentration can be expressed as a percentage or in parts per million (ppm). Since both values represent the same concentration, you can simply use the unit that is specified in your procedure. One percent is equivalent to ten thousand ppm.

\text{percent} = \dfrac{\text{ppm}}{10{,}000}

Typical dilution ratios for disinfectant bleach.

The concentration required depends on the application. The concentration needed to disinfect food surfaces is much lower than that required for treating blood loss. The following table shows typical target concentrations and the amount of regular 6% bleach required to achieve these concentrations.

Use	Available chlorine	From 6% bleach
Food-contact sanitizing	100 to 200 ppm	about 1:300
General surface disinfection	1000 ppm	about 1:60
Mould and heavy soil	2500 ppm	about 1:23
Blood and body-fluid spills	5000 ppm	about 1:11

Apply the solution to a surface that has already been cleaned and leave it for the contact time stated on your policy, usually between five and ten minutes. Rinse if necessary and allow the object to air dry.

Safe handling of bleach:

Never mix bleach with ammonia, acids or other cleaning products.

Mixing bleach with ammonia produces chloramine gas while mixing it with acids such as vinegar releases chlorine gas. Both gases are dangerous if inhaled.

Put the bleach in the water, not vice versa. Work in a well-ventilated area and wear gloves and safety glasses. Diluted bleach loses its effectiveness within about one day, so prepare only as much as you need.

This calculator is only a general guide, please follow the bleach label instructions and your local public health guidelines. Check important solutions with chlorine test strips.

Frequently asked questions

What is the difference between percentage and parts per million?: Both express concentration. One percent is equivalent to ten thousand parts per million, so 0.1% is equivalent to 1000 ppm. Use the units specified by your cleaning and disinfecting policy.
How much bleach should be mixed with water to disinfect?: It depends on the desired concentration. For general surface cleaning about 1000ppm is required which corresponds to a mixing ratio of approximately 1:60 starting from normal 6% bleach solution. Lower concentrations between 100 and 200 ppm are used for surfaces that come into contact with food, while concentrations around 5000 ppm corresponding to a ratio of about 1:10 is required for cleaning blood or body fluid contamination.
Can I use bleach with a concentration of 8.25%?: Yes. If you enter the original concentration of 8.25, then the calculator will adjust accordingly. The higher the bleach concentration is, the less bleach and more water it takes to achieve the same target concentration.
How long is diluted bleach effective?: Not for very long. Diluted bleach loses its disinfecting power after about 24 hours, so you should only prepare the amount that you will need and mix it fresh daily.
What substances must you never mix with bleach?: Never mix bleach with ammonia, acids such as vinegar or lemon juice, or other cleaning products. These combinations create toxic chlorine and chloramine gases. Always add the bleach to water first and work in a well-ventilated area.

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Disclaimer: This calculator is provided for general informational and educational purposes only. Our calculators are under active development, and results may be inaccurate, incomplete, or unsuitable for your situation. Always verify the figures independently and seek advice from a qualified professional before relying on them. We make no warranties and accept no liability for any loss or decision arising from use of this tool.

References

Centers for Disease Control and Prevention: Cleaning and disinfecting with bleach
US CDC guidance on preparing and using bleach solutions safely.
LibreTexts Chemistry: Dilutions and Concentrations
Educational reference for the C1V1 = C2V2 dilution relationship.
Sodium hypochlorite (Wikipedia)
Background on the active ingredient in chlorine bleach and its chemistry.