When using colour as a coding mechanism, the number of colours used should be:

a. 7 or fewer b. 9 or fewer c. 6 or fewer d. 8 or fewer

Potentially a question for cognisc Stack Exchange but this question relates to the amount of colours a user can perceive at a given moment and in terms of UX, I guess, assigning colours to categorise elements.

For example, how many colours can the human brain take in at a given moment of time without over-complicating a design. For example, according to Dr Halberda (2006) colour plays a major role in catching the attention of people. One can select and attend up to 70 items at once if they are of the same colour. Colour-coding helps to keep things organised and simple. But what Halberda failed to account for is how many colours can be categorised at a given moment in time.

These are the only answers providing by the organisation body so unable to give a min or max answer. The meaning of fewer is less

  • 2
    Needs much more context. What is the max number, what is the min number? What is the meaning of ewer?
    – rk.
    Commented Jun 11, 2013 at 15:21
  • You mean like the colour coding in the new Gmail app? Commented Jun 11, 2013 at 15:48
  • Edited comment to account for context.@AndriodHustle - similar yes, so how many can we interpret at a given moment without forgetting what each colour is intended to represent? Commented Jun 11, 2013 at 16:20
  • Can we remove the multiple choice options from the question? It sounds like you want us to answer an exam question for you.
    – Matt Obee
    Commented Jun 11, 2013 at 16:27
  • You might be interested in Trello's treatment of the subject, regarding its use of colored labels as well as being able to switch to patterns instead of colors for color-blindness: webapps.stackexchange.com/questions/19129/…
    – jzx
    Commented Jun 11, 2013 at 17:34

1 Answer 1


We don't know what precisely you want to do with colours. But don't rely on colour alone to convey information. Otherwise your work would not be accessible. There are colour-blind people. And, if you do use colours, choose colours not close to each other.

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