1.4.3 - Text contrast

Make sure that text has enough contrast against the background colour.


Text must have a contrast ratio of at least 4.5:1 (or 3:1 in some cases) against its background colour.


  • 'Large scale' text has a contrast ratio of at least 3:1 against its background.
  • Text that is not 'large scale' has a contrast ratio of at least 4.5:1 against its background.

'Large scale' text is defined as text that is larger than 18pt/24px, or 14pt/18.5px and bold.


  • Good colour contrast assists people with vision impairment (including colour blindness) and cognitive impairments when viewing content.
  • It also benefits all users in a brightly lit environment.

Official wording in the Web Content Accessibility Guidelines

1.4.3 Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following: (Level AA)

  • Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1;
  • Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
  • Logotypes: Text that is part of a logo or brand name has no minimum contrast requirement.

See the W3C's detailed explanation of this guideline with techniques and examples.

Guidance for Design

User tools like Sketch's Stark plug-in, Colour Contrast Analyser to make sure that text has sufficient contrast.

More guidance for Design