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The Hair Colour Numbering System Explained

Published on 7th August 2014

You’ve decided to dye your hair platinum blonde, but do you go for the 10.12 or the 10.21? What do those numbers even mean?

Let me first explain the difference between depth and tone.

Colour Depth

This is how light or dark the colour is. It doesn’t take into consideration variations in colour, just whether your hair is very dark, very light or somewhere in between. Here’s how it’s typically worked out for natural hair colours:

1 Black
2 Very Dark Brown
3 Dark Brown
4 Medium Brown
5 Light Brown
6 Dark Blonde
7 Medium Blonde
8 Light Blonde
9 Very Light Blonde
10 Lightest Blonde

Natural redheads will usually be somewhere between levels 3 (dark auburn) and level 7 (strawberry blonde).

This level system is somewhat up to interpretation so one person’s light brown is another’s dark blonde.

You may also see 12 as the first number on a hair colour (on Wella hair dyes, for example) and it usually indicates a high-lift, ultra-light blonde shade. It’s not a natural depth level.


Tone describes the colour present in the hair. So whether your hair is a dark shade like Blue Velvet or something pastel like Blissful Blue, the main tone would be blue. This numbering system is concerned mainly with natural colours though.

Natural hair tends to have ash (cool or greyish tones, seen in mousy brown hair), gold or red tones. Natural dark blondes tend to have ash tones in the hair, ginger hair has red tones, medium brown may have gold or ash tones and very black hair usually has red tones.

Deconstructing the Numbering System

Now you know the difference between depth and tone you can work out what colour you can expect based on a hair dye’s numbering system.

Let’s take the example of a colour I used to use; L’Oreal Diacolor Richesse in 6.23 “Mocha Gold”.

6 is the depth of colour. Referring back to the depth chart above you’ll see that 6 is a dark blonde. The part after the decimal point refers to the tone.

Unfortunately manufacturers tend to number the tone differently. This system is known as the International Colour Chart (ICC) but there’s nothing standardised about it. Let’s take a look at L’Oreal’s numbering system.

Natural – 0
Blue Ash – 1
Violet – 2
Gold – 3
Copper – 4
Mahogany – 5
Red – 6
Green Ash – 7

So 6.23 is dark blonde with a dominant tone of violet (2) and a secondary tone of gold (3). It makes quite cool-toned colour.

Some manufacturers will use letters instead of numbers such as Goldwell:
N – Natural
A – Ash
BV – Blue Violet
V – Violet
R – Red
B – Brown
G – Gold
K – Copper
RB – Red Brown

The letters here can also denote intensity; a 5RR would be more vibrant than a colour labelled 5R. You can see that based on this lettering system my L’Oreal 6.23 would translate to 6VG although I would expect a bit of colour variation from one manufacturer to the next.

So if that all seemed a bit confusing it’s because every manufacturer numbers (or letters) their shades slightly differently and the only part that’s universal is the depth number. Typically hair stylists will train in one brand and learn their numbering system.

When purchasing professional hair colour, check out the numbering system for that particular brand and take a look in the swatch book before buying. Your base hair colour, both depth and tone, will have a great effect on how the colour takes. I’ll cover how colours interact in a future article, but you can read up on the colour wheel in this article.

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