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How to Mix Bleach and Developer | 9 Easy Steps

Visiting the salon is expensive, so you might be wondering how to mix bleach and developer to lighten your hair at home. We’ll share our top tips to give your hair a DIY salon-perfect look below.

Mixing Bleach and Developer: A Summary

Hairdresser showing us how to mix bleach with developer


Mixing bleach and developer takes practice, and getting it right is crucial for your hair’s health and avoiding embarrassment. So if you’re a beginner, the steps below will help you safely and effectively lighten your hair.

  1. Understand how bleach and developer interact
  2. Choose the developer volume
  3. Gather your materials
  4. Measure the bleach and developer
  5. Add powdered bleach
  6. Squeeze in developer
  7. Remove clumps
  8. Do a patch and strand test
  9. Always have extra ingredients

How to Mix Bleach and Developer in 9 Easy Steps

Are you ready to lighten your hair for the summer or a special event? By following the steps below, you’ll soon get to show off your new color.

1. Understand How Bleach and Developer Interact

We won’t dive too deep into the science here, but it’s crucial to understand how bleach and developer work before applying it to your hair. For starters, hair bleach isn’t the same kind of liquid bleach you keep under your kitchen sink.

Instead, it comes in a powder form with the purpose of stripping pigment from your hair cuticles. It’s a powerful chemical that requires special care, as hair bleach poisoning can occur.

Interestingly enough, bleach won’t give you the desired results without a developer, nor will it work if you let it dry out. Similarly, developers won’t work on your hair unless you mix them with bleach. 

That’s because developers contain hydrogen peroxide, which activates bleach, helping remove the natural color from your cuticles. Developers come in a cream form, allowing it to mix easily with powdered bleach, forming a paste.

2. Choose the Developer Volume

Mixing bleach and developer is truly an art, given that there are many different developer volumes. Each volume refers to its strength, with the higher volume developers having more power to turn your hair a lighter color. 

The types of developers you can choose from include:

  • 10 Vol
  • 20 Vol
  • 30 Vol
  • 40 Vol

If you’re looking for a mild developer that will lighten your hair slightly without you having to worry about a drastic color change (and don’t want to decide what developer to use) 10 volume developer is an excellent choice.

Some people who lighten their hair for the first time choose 10 vol as practice since there’s less risk of damaging their hair. That said, 20 vol is the most popular developer strength. That’s because it lifts hair color two shades while remaining relatively mild in strength.

In fact, if you purchase a hair-lightening kit from the store, you can pretty much bet that it’ll come with 20 volume developer. Should you opt for a 30 volume developer, you can expect your hair color to lift three levels.

30 vol is a common choice that salons use for lightening hair, as it does an excellent job of activating bleach powder. There’s no need to use 40 volume developer if you’ll be lightening your hair at home.

Doing so can get you in dangerous territory, given that its potency can destroy the hair and irritate your scalp. While 40 vol developer has its place in the hair-lightening world, you should only let professionals apply it.

3. Gather Your Materials

At this point, you should have an idea of which volume developer you want to use for your hair. However, you’ll need more materials than just that. Below is everything you’ll need to get started before we talk about how to mix bleach and developer.

  • Developer
  • Powdered bleach
  • Plastic bowl
  • Brush
  • Gloves
  • Parting combs
  • Clips
  • Towel

You’ll also need some aluminum foil if you’re using bleach and a developer to do highlights. When choosing your developer and powdered bleach, we encourage you to buy them from the same brand. That’s because every brand makes these materials a little differently.

So, if you mix and match developers and powdered bleach from different brands, it could give you less than desirable results or even cause unnecessary damage to your hair.

4. Measure the Bleach and Developer

You can’t just pour some bleach into a bowl, squeeze in some developer, and call it a day. Instead, it’s crucial to stick with a measured ratio of these ingredients. The standard ratio for developer and bleach is a 2:1 ratio.

That means you’ll need to blend one part of bleach for every two parts of developer. You’re free to measure out developer and bleach according to your preference. The easiest way is to use a measuring tool to get the correct amounts.

It doesn’t matter the tool you use—as long as it’s the same for both bleach and developer, you’ll get the correct ratio. Alternatively, you can weigh these ingredients to get the ratio. You might be wondering — do you have to change the ratio according to the developer’s volume?

No, you don’t. By sticking with a 2:1 ratio, you can be sure that you’ll get an even, effective blend that will lighten your hair. Although some people use ratios other than 2:1, doing so can lead to undesirable color results at best and hair or scalp damage at worst.

In fact, studies show that scalp burns occur if you use bleach in excess or apply unnecessary heat. It can even lead to swelling and epidermal thinning.

5. Add Powdered Bleach

Remember how we included a plastic bowl on our materials list in step number three? Using a plastic bowl is crucial because certain other materials, such as metal, may instigate a chemical reaction with the beach or developer. 

So, you’ll want to place your 2:1 ratio developer and bleach powder directly into a plastic bowl.

However, you should always put the powdered bleach in the bowl first. Doing so will help you create a creamier, more liquid texture—something crucial for bleach to work its magic on your hair.

6. Squeeze in Developer

It’s now time to mix developer with the bleach. To do so, add small amounts of developer and use a paintbrush or other brush designated for this mixture to combine the ingredients gradually. Although you can add all the developer at once, we discourage you from doing so.

The reason is that clumps can form. So, with every bit of developer you add, use your brush to mix it with the bleach powder. After doing that a few times, you should have a bowl full of mostly well-blended developer and bleach.

7. Remove Clumps

The stray clump will likely form no matter how careful you are when mixing bleach and developer. It may sound harmless, but we assure you it isn’t—clumps prevent developers from activating bleach, meaning it can leave your hair with patchy shades of lighter and darker colors.

So, use your brush to go through the bleach and developer blend, squashing any chunks you may find and mixing them in with the liquid.

8. Do a Patch and Strand Test

We understand how exciting it is to start lightening your hair once your bleach and developer mixture is ready. However, it’s best to follow the mixing steps here with a tiny amount of bleach and developer first.

Then, perform a patch test by placing a small amount of the mixture behind your ear or on another part of your skin that’s out of sight. Leave the mixture on your skin for 24 hours. If you don’t have a reaction, you’re in the clear.

The Food and Drug Administration recommends doing a patch test before every application. While this might not be necessary as long as you use the same bleach and developer products, it certainly can’t hurt, especially if you have sensitive skin. 

Meanwhile, do a similar test with a strand of your hair that isn’t very visible. Leave the mixture on for the recommended time before rinsing it out and seeing if you’re happy with how much it lightened your hair. 

Although this can feel like a cumbersome step, it’ll give you peace of mind that the color will turn out how you want it to before you apply the bleach and developer to your whole head.

9. Always Have Extra Ingredients

There’s a fine line between mixing bleach and developer so that you have enough to lighten your hair and not so much that it begins to dry out. So, whether you didn’t mix enough bleach for your hair length or you’re encountering issues with the mixture drying, having extra powdered bleach and developer on hand is crucial.

Here’s some good news: Once you bleach your hair, it’ll receive conditioning treatments better than before because it becomes more porous than non-bleached hair. As long as you use bleach and developer within the recommended amounts and timeframe, they might even improve the softness and quality of your hair.

Frequently Asked Questions

Featured image for a piece title how to mix bleach with developer with these products on a table

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Do you still have questions about how to mix bleach and developer? We’ve rounded up some of the most common inquiries here.

What happens if you put too much developer in bleach?

If you put too much developer in bleach, the mixture will become runny. That’s a disadvantage to your coloring, as the lighter tone may not last as long.

Can I bleach my hair twice with 20 developer?

Yes, you can bleach your hair twice with 20 developer. However, you may want to consult a salon before doing this, as overusing bleach and developer can lead to hair damage.

How long should I leave bleach in my hair?

You should leave bleach in your hair for a maximum of 45 minutes. After the 45-minute mark, bleach no longer lightens hair and starts to damage it. For this reason, it’s crucial to keep track of how long you leave bleach in your hair, starting with the first strand application.

Should I bleach my roots first or last?

You should always bleach your roots last, given that the heat from your scalp speeds up bleach’s lightning action. So, you should always bleach the rest of your hair first and finish with your roots.

Should I bleach my hair dry or wet?

If you’re going for a more natural appearance, it’s best to bleach your hair when it’s wet. Bleaching your hair dry will create bolder colors. However, wet hair is especially fragile, so it’s best only to let an experienced professional bleach wet hair.

So, How Do You Mix Bleach and Developer?

The best way to mix bleach and developer is to use the same brand products, apply the powdered bleach in a plastic bowl first, and gradually stir in the developer. By following our advice here and doing patch and strand tests, you’ll rock a beautiful lighter hair color.

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