Skip to Content
HomeCommon Questions

How Much 40 Volume Developer to Mix with Bleach?

Mixing bleach and 40 volume developer can be a daunting task for many. It requires precise measurements, careful timing, and understanding the potential effects of using too much of either ingredient.

But when done correctly, this combination can dramatically affect hair color. 

In this blog post, we’ll explore what exactly a 40-volume developer is and how it should be mixed with bleach safely and effectively for maximum results without causing harm.

What is a 40 Volume Developer?

40 volume developer

40 Volume Developer is a type of peroxide-based hair color developer used to lighten or darken the natural pigment in the hair. It is typically mixed with bleach, toner, or other coloring agents and applied directly to the scalp.

The strength of 40-volume developer is measured by its concentration level—the higher the number, the stronger it is.

How Much 40 Volume Developer to Mix with Bleach?

The recommended ratio for mixing 40-vol developer to bleach is 2:1. That means you need to mix two parts of the developer for every one part of bleach.

This combination will provide enough lift in a single application to lighten your hair by up to four levels. 

A 40-volume peroxide contains 12% hydrogen peroxide, which is strong enough to open the cuticle layer and allow the bleach powder’s active ingredients to penetrate your hair shafts.

Maintaining Your Bleached Hair

40 volume developer and bleach mixture ratio

Here are four steps to take care of your hair property after using a 40-volume developer and bleach mix:

1. Following the bleaching process, use a deep conditioning treatment on your hair to replenish moisture that may have been lost and prevent further damage.

2. Use sulfate-free shampoos when washing your hair going forward since sulfates can strip away natural oils produced by our scalps leading to dryness which is not ideal, especially if you’ve just recently used a chemical-based product like bleach on it already. 

3. When drying off freshly washed tresses, always opt for air drying over blowdrying whenever possible since heat-styling tools can cause even more damage than what was done through bleaching. 

4. Lastly, avoid swimming pools (especially chlorinated ones) altogether because chlorine has harsh effects on colored treated tresses, making them look dull and lifeless. 

So, the 40-vol developer to Bleach mixture ratio is 2:1. The right type of bleaching agent should be chosen based on hair type and desired results. It is also essential to take proper care of your hair after using a mixture of 40-volume developer and bleach in order to prevent damage or discoloration.

With the correct knowledge and precautions, you can safely use 40 volume developer to mix with bleach for beautiful results.


Can I use 40 volume developer with bleach?

Yes, you can use 40 volume developer with bleach. Just be cautious when combining these two products, as their strength can be potent and may result in hair damage if not used correctly.

Speaking with a specialist before trying this procedure is advisable to guarantee safe and successful results.

How long do I leave 40 developers on with bleach?

You should not leave any developer in bleach for more than 10 minutes.

Bleach can cause damage to your hair and scalp, so be cautious when using this product. After 10 minutes, rinse the developer out thoroughly with cool water and follow up with a deep conditioning treatment if desired.

Keep your skin from coming into contact with bleach for long periods, as this can cause inflammation or even scalds. Also, ensure that the area where the developer is being used has good air circulation and that gloves are worn for protection.