Changing your hair colour can be an exciting transformation, but it can be confusing without a basic understanding of the hair colour numbering system. Knowing what the numbers on hair colour charts represent is key to making the best decision for your new look. Here's a simple guide to understanding these numbers and how they work in the world of hair colour.

The L’oreal professionel colour numbering system explained

During your consultation at a salon, your colourist will use an international numbering system to determine which shades and tones will best suit you. This system helps break down the depth and reflect (tone) of the hair colour.

Generally, there can be up to four digits in a hair colour number, with one or two digits before the decimal point and one or two after.

For example, colour codes like 3, 5.8, 6.13, and 10.21 are all part of this system.

Understanding hair colour charts

What is a natural base colour?

The numbering system is primarily made up of 10 levels, which help identify the depth of your natural hair colour. This ranges from the darkest to the lightest: • 1: Black • 5: Light Brown • 6: Dark Blonde • 7: Blonde • 10: Lightest Blonde

Before any colour is applied, your colourist will analyze your natural base colour to identify which depth level you are starting from.

What is base colour?

The first number in the hair colour chart represents the base colour.

This number indicates how light or dark the shade is. It sets the foundation for the rest of the hair colour formula.

What is a tone or reflect of colour?

The numbers that appear after the decimal point indicate the tones or reflects present in the colour. These reflect whether the colour has cool or warm undertones. For instance: • .1: Ash (cool tones with blue or green hues) • .2: Iridescent (violet tones) • .3: Golden (warm tones) • .4: Copper (reddish tones)

Your colourist may adjust these tones depending on your desired result. For example, if you want to prevent a blonde colour from becoming too warm, your colourist could add more violet (.2) or ash (.1) tones to neutralize the yellow or orange hues that may naturally develop.

Aside from the base colour and tone, the final result can be influenced by other factors such as your natural pigment and the undercoat of your hair.

This is why a consultation with a professional is important—they will consider all these aspects, along with your skin tone and eye color, to create a personalized colour that enhances your features.

A deeper understanding of the hair colour numbering system can help you better communicate with your colourist and ensure you get the exact shade you want. With the right combination of depth and tone, you can achieve a look that’s perfectly tailored to you.