International Colour Charts for Hairdressing

Hair colour charts make us want to do crazy stuff to our hair. That aside, when we are looking at hair dyes, they usually have a code and description to give us an idea of how dark it is (the depth) and what colours are in the finished colour (the tones). While many manufacturers use their own in-house system, there is a global numbering system to create a more precise definition of hair colour. It’s called the International Colour Chart, which uses numbers to convey what the depth of the colour is, and what tones (if any) are in the colour.

What is the International Colour Chart?

The International Colour Chart (ICC) is a numerical system used worldwide to classify hair colour. It means that each hair colour has a definition that is recognised around the globe, and can be used by manufacturers on hair colour charts and tubes/boxes of hair dyes.

Professional tints using the ICC. Top: lightest blonde with cool ash tones. Bottom: medium brown with cool mahogany (chocolate brown)

Each hair colour is given a number, which tells us two things: firstly, the depth and, secondly, if there are any tones in the colour.

The depth number is usually separated from the tone number by a dividing symbol like a decimal point, a slash or a hyphen – for example: 4.6, 4/6, 4-6 all say the same thing.

Not all hair colour manufacturers use the ICC – some have their own in-house numbering system, like using letters to represent the different tones e.g. R for red, or M for mahogany.

Also, even if a manufacturer is using the ICC system, colours can vary; so one brand’s 4 (medium brown) can be different to another brand’s 4.

It is not perfect, but goes a long way to standardising how we define hair colouring products.

How Depth and Tone are Numbered

Depth

Depth is given a whole number from 1 to 10, where 1 is the darkest hair colour (black) and 10 is the lightest (lightest blonde). Some manufacturer’s also use 11 and 12 on their colouring products to account for the blondest of the blonde.

The ten natural hair colours, or depths, with the ICC number

Tone

Tones are numbered from .0 to .9. Hair colouring products can have just the base colour without any tones, or they can have up to three tones in it, though one and two tones are most commonly seen.

The first number given for the tone is the primary tone, and the second number is the secondary tone. The primary tone has more influence over the final colour than a secondary tone.

Example showing how tones can alter the colour of light blonde (hair depth 8)

For example, an 8.1 is a light blonde with a cool ash tone, while a 8.13 is a light blonde with mainly a cool ash tone, but the final colour also has a hint of gold.

How a red tone can be added at different intensities to alter a medium brown base colour

Zero is used to indicate how intense a tone is. For example, a 4.06 is a medium brown with just a hint of red, creating a warm coffee colour, while a 4.60 is medium brown with a more definite and obvious red tone to the hair (more than a 4.6 would have).

Double tone means a greater intensity and vibrancy of that particular tone, so a 4.66 means a strong red tone on medium brown hair.

Mahogany (a mix of red and purple) is normally used with another tone in hair colour, rather than just on its own. Mahogany itself is neither warm nor cool – the tone it’s paired with determines whether the final hair colour is warm or cool. For example, a 4.15 (chocolate brown) is a cool colour; whereas a 4.56 would be a warmer colour.

Hair Colour Charts

Each manufacturer lays out their hair colour charts differently, though they are generally logical and organised into tone groups (like mahogany, red or ash).

Below are some examples of hair colour charts to see how they are laid out and how the ICC is used. Click on the hair colour charts to go large. The temptation to dye is strong. Resistance is futile.