Hair Coloring

The Universal Hair Color Numbering System: Explained

I clearly remember the first time I went into a drug store to buy hair dye. So many brands and types of hair dyes, and different numbers written on each box. Even though I knew the brand I wanted to get, the numbers were quite confusing. What I didn’t know at the time was that these numbers follow a universal system, so we will try to simply explain it for you to easily decide on your next hair DIY hair color.

Firstly, you should know that the hair color number is made of 3 numbers with a slash or period after the first number. The first number indicates color level and depth, while the second and third numbers indicate color tone.

We will break it down in details and it is quite simple as a matter of fact.

1- Hair Color Depth:

hair color chart


Hair color depth is the first number in the color code before the slash or the period, and indicates the essential color in the dye. It is indicated by 10 numbers, 1 being the darkest black, and 10 being the lightest blonde. The color depth numbering is a universal system that is the same among different brands of hair dye.


2- Hair Color Primary Tone:

This is the second number in the color code and the one right after the slash or period. It indicates the undertone of the dye and the hue it gives. The undertones mainly determine how cool or warm the final color will be. You should know that the numbers for undertones vary between brands, so you should always consult the color chart of each brand before deciding. For reference, you can see the differences between the undertone chart of L’Oréal (left) and Wella (Right).

Hair color undertone chart











3- Color Reflect:

This is the third number of the hair color code that indicates the reflection of the color. It is much less visible than the essential color and undertone, so your priority in choosing your dye color shouldn’t be mainly based on it.


What color should you choose?

Generally, if you’re using a permanent dye, you should know the depth shade of your current hair color. Then you should choose a color that is 1 or 2 shades lighter or darker than it. If your hair is a very dark brown (2 on the depth scale), you can use a number 1 dye, or as light as number 4.