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WCAG reaches consensus on threshold colours
Some automated contrast checkers rounded contrast rations up

This is color #777777, does it fail WCAG 1.4.3?


  • Wave now fails it at 4.48:1
  • Colour Contrast Tool passes it at 4.5:1
  • Code Sniffer passes it at 4.5:1
  • Juicy Studio pass it at 4.5:1
  • Tenon Passes it least 4.5:1
  • Axe fails it at 4.48:1
  • Snook fails it at 4.48:1
  • Chrome accessbility tools just added code to pass it rounding to 4.5:1

It turns out the actual value appears to be 4.48:1, and Juicy studio, chrome a11y tool, code sniffer, Tenon, and the Colour Contrast tool have rounding to the nearest 10th which pushes it to 4.5:1 to a passes. WCAG says it must be "at least 4.5:1". Webaim tweeted.

I also filed a bug with WCAG to clarify in the understanding document that rounding up to 4.5:1 is either OK or not.


<p style="color:#777777">This is color #777777</p>

Working group reaches consensus

Working Group consensus reached Oct. 27, 2016, regarding the original intent of the Success Criteria. No rounding allowed. It's a threshold value. In other words you cant have any contrast less than that no matter what you did with rounding.


Feel free to comment on Twitter @davidmacd

Author information:

David MacDonald is a veteran WCAG member, co-editor of Using WAI ARIA in HTML5 and HTML5 Accessibility Task Force Member. Opinions are my own.


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