Ratio of bleach to developer

What Ratio Of Bleach To Developer Do I Use | Mixing Bleach Safely At Home

Bleaching your hair at home? You have to get the ratio of bleach to developer right, especially if you have long hair or dark hair. It matters if you use a 20 developer, 30 developer or 40 developer.

If you have dark hair, you would have wanted to get it dyed a lighter color like blonde, pastel or ash. But for this you need to bleach your hair to get rid of exisiting color pigment first.

I always suggest going to a professional hairstylist to get a bleach job, but for a lot of people this has become difficult due to current circumstances.

And I’ve seen one horror story after another about bleaching hair at home gone wrong. And these usually have to do with using the wrong bleach to developer ratio.

So in this article I’ll talk about the right ratio of bleach to developer you should use while mixing them together and how to apply them correctly on your hair. 

What Ratio Of Bleach To Developer To Use

Exact Ratio Of Bleach To The Developer You Should Use (20, 30, 40 Developer)

Given below is the corect ratio of bleach to developer you should use depending on the type of developer: 

  • 30 developer to bleach ratio – 2:1 
  • 20 developer to bleach ratio – 2:1
  • 40 developer to bleach ratio – 2:1

Surprised? Yup. The amount of developer you use on the bleach has got nothing to do with the strength.

Most hairstylists suggest using two parts of developer for every one part of bleach as this ratio gives you the right consistency of liquid.

This ratio gives you a fairly runny texture of bleach that can be easily applied to hair. Now this consistency is good for long hair as it drips down enough to spread throughout the tresses, but it’s not thin enough to go down your face.

A 20 developer, 30 developer and 40 developer are only assigned these numbers to indicate how much they lift your existing hair color. They are not an indication of how much developer to add.

Here is a quick guide if you’re using a developer and bleach packet:

  • For every 50gm bleach powder you’ll need 100gm of developer
  • For every 100gm of bleach you’ll need 200gm of developer 

If you’re using ounces instead of grams the ratio will be the same. 

  • For every 1oz of bleach, you’ll need 2oz of developer 
  • For every 2oz of bleach you’ll need 4oz of developer 

If you use too much developer your mixture will end up runny and can get on your face, skin, etc. causing burning and inflammation. If you use too little developer the mixture will be too thick and won’t adhere to hair well. This will cause uneven bleaching.

Note: This ratio of 2:1 will change if you’re planning to bleach your hair for a balayage. We do NOT want the bleach to spread all over in case of a balayage. So a thicker paste is required when doing a balayage or covering up small areas of hair. In this case you should use the bleach and developer in the ratio 1:1. With only one part of developer added to one part of bleach. 

How To Measure Bleach And Developer?

how to measure bleach and developer

You shouldn’t have too much difficulty in measuring the bleach and developer as most bleaching kits come with measuring tools like a spoon that you can use to get the right ratio.

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However, if such thing isn’t unavailable you can use old measuring spoons you’ve got in your kitchen that are used to measure baking ingredients. 

Just remember to wash and dry them thoroughly before use and never use these spoons for measuring food once you’ve got bleach in them. 

How To Mix Bleach And Developer?

how to mix bleach and developer ratio

If you’re going to lighten your hair at home and have got the bleaching powder and developer ready it’s now time to mix them.

But before you start make sure you have all items handy: 

  • Plastic gloves
  • A plastic mixing bowl
  • A plastic hair brush
  • Measuring scoop

Measure out the bleach using the scoop and add it to the bowl. You can use the same scoop to add two measures of developer to the bowl over the bleach. Now, mix it well using the brush. And don’t forget to wear gloves while doing this to prevent getting bleach on your skin.

Mix the bleach and developer well until you get rid of any lumps that are formed and the mixture is a smooth, runny consistency. 

Lumps in the mixture will prevent your hair from getting bleached evenly while a smooth liquid ensures proper application. 

What Type Of Bleach And Developer Do I Use?


There are different strengths when it comes to bleach as well. If you have dark brown hair or black hair, you should use a strong bleach like the Clairol Professional BW2 Hair Powder Lightener on your hair.

But if you have blonde hair and want to go platinum or have light brown tones, something more mild like the eZn Creamy Hair Bleaching Cream would be sufficient.

Also there is a new variety of bleach called the “blue bleach”. This bleach prevents hair from turning orange or getting brassy undertones as the blue pigments in there neutralize the brasiniess.

But you don’t have to use the blue bleach on blonde or light brown hair as the chances of it turning brassy after bleaching is less.

If you’re dying really dark or black hair, blue bleach might come handy.


what developer to use with bleach for dark hair

A lot of people (including me at the beginning) get really confused with developers. What exactly are they? 

Well, a developer or activator is nothing but hydrogen peroxide that helps in lifting the hair cuticles making it easier for bleach to remove the color pigments. 

The number on the developers signify its oxidation potential or strength. So the bigger the number the more effective it is at removing hair color. But at the same time, it’s also more corrosive and damaging.

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Now there are developers ranging from 10 to 40. A 10 developer is very mild and doesn’t exactly lighten hair just brings it down a tone or two.

Now 20 and 30 developers are the most commonly used ones. The 20 developer can lift hair upto 2-3 levels and a 30 developer upto 4 levels. 

I usually have to go for a 30 developer each time as I have dark hair but if you have lighter hair a 20 developer would work just fine.

So what about the 40 developer? Well, it’s very powerful and it can lift hair upto 6 levels. But trust me it’s too strong to mess with at home.

It contains 12 percent peroxide and is known to cause burning and scabs on the scalp when used to dye roots. 

If you’re trying a 40 developer do it under professional supervision.

Related: How To Dilute Developer For Hair Dye

FAQs About Ratio Of Bleach To Developer

bleach powder and peroxide measurements

What is the correct procedure of measuring bleach and developer for hair dye?

The correct procedure for measuring bleach and developer when dyeing hair can vary depending on the specific instructions provided by the hair dye product you are using.

However, I can give you a general guideline that is commonly followed. It’s important to note that the measurements and ratios may vary depending on the specific brand and product you are using, so always refer to the instructions provided with your hair dye kit for the most accurate information. Here’s a general procedure:

  1. Read the instructions: Carefully read and understand the instructions provided with the hair dye product. Different brands and types of hair dye may have specific guidelines and measurements, so it’s important to follow them accurately.
  2. Prepare the mixing bowl: Get a non-metallic mixing bowl or container. Metal can react with certain hair dye chemicals and alter the results, so it’s best to avoid it.
  3. Measure the bleach: Using a measuring spoon or scoop that is specifically designed for hair dye, measure the recommended amount of bleach powder or cream. This amount will depend on the brand and the desired level of lightening. The instructions should specify the amount to be used.
  4. Add the developer: In the same mixing bowl, add the appropriate amount of developer. The developer is typically provided in a separate bottle or container that comes with the hair dye kit. The instructions will specify the volume or percentage of the developer to be used.
  5. Mix thoroughly: Use a tint brush or a stirring tool to mix the bleach and developer together until you achieve a smooth and consistent mixture. Make sure there are no lumps or clumps.
  6. Follow the instructions: At this point, the instructions provided with your hair dye kit will guide you on how to apply the mixture to your hair. They will specify the application technique, processing time, and any additional steps you need to take.

Remember, it is essential to carefully follow the instructions provided with your specific hair dye product, as different brands may have slightly different procedures and measurements. It’s also a good idea to conduct a patch test prior to applying the hair dye to check for any adverse reactions and to ensure you achieve the desired results.

What happens if you put too much developer in bleach?

The developer is supposed to help the bleach penetrate better into your hair cuticle, making it more powerful at removing hair pigment or “lifting”your hair color.
If you add too much developer into bleach, your mixture first of all, will become too runny. The liquidy-consistency can make it difficult to adhere to hair for long and it can also run down your face if you’re not careful.
When it comes to the formula, too much developer can cause excessive lifting of hair dye. So your hair can get damaged easily. It also makes the bleached hair look patchy with less color in certain areas than others. 

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What is the ratio of bleach to 30 developer?

If you’re using a 30 volume developer should add it to bleach in the ratio 2:1. This means that for every one part of bleach you should add two parts of developer.

What ratio should I use for bleach?

No matter what type of developer you are using (30 developer, 20 developer or 40 developer) always mix developer and bleach in the ratio 2:1. 

How much developer do I mix with quick blue bleach?

If you are using the L’Oreal Quick Blue Bleach, you can use the 1.5 to 2.5 oz of developer with 1 oz of the bleach. If you’re using a plastic wrap or foil technique for bleaching, it might be enough to use 1.5-2 oz of developer. 

What is the ratio of bleach to 20 volume developer?

Even if you’re using a 20 volume developer should add it to bleach in the ratio 2:1. This means that for every one part of bleach you should add two parts of developer.

If you’re bleaching your hair at home, mixing the bleach the right way is very important. Here you have to pay attention to two things.

Number one, use the right developer with the bleach, depending on the amount of “lift” you want each time. 

So use a 20 developer if you have light hair and want to lift hair to only one or two levels. Or you can use a 30 developer if you want a higher level of lift. 

But no matter what kind of developer you use, l always recommend you apply it in the ratio 2:1 with two parts of developer added for every one part of bleach. 

Why You Should Trust Haireveryday?

The author of this article, Leah Marie Priest has a degree in Cosmetology with years of experience in dealing with hair care, scalp care, and hairstyling. As someone who extensively deals with all kinds of hair textures, products, styling methods and more, hair Leah Marie knows what kind of products and procedures suit each hair type and person. We have also tested these hair products and processes ourselves to provide you an unbiased review about every product. Each of our articles are also reviewed by a team of medical professionals so that you get the most accurate and expert-reviewed information.

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What Happens If You Start Dyeing Hair Without Developer ?

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