Links must be distinguished from surrounding text in a way that does not rely on color

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Rule Description

Ensures users who cannot distinguish between colors can tell when text is a link by verifying the link has either a distinct style that does not rely on color, or has a contrast difference of greater than 3:1 (which alerts you that manual testing is required).

The Algorithm, in Simple Terms

Checks all links that appear in blocks of text for a color contrast difference of at least 3:1 with the surrounding text to ensure that users who cannot distinguish between the colors can still find the link.

This rule looks at common ways to distinguish links from surrounding text, including underline, font styling, border and background. If the link has a distinct style that does not rely on color, there is no violation (pass). If the link has no distinct style and it has a contrast difference less than 3:1, there is a violation (fail). When the link has no distinct style and it has a contrast difference of 3:1 or greater, you must verify that the link gets distinct style on focus and hover (manual testing required), as this cannot be automated reliably.

Why this is Important

Some people with low vision experience low contrast, meaning that there aren't very many bright or dark areas. Everything tends to appear about the same brightness, which makes it hard to distinguish links. Text that is too close in luminance (brightness) to the background (or adjacent text) can be hard to read.

How to Fix the Problem

Ensure all links that appear in blocks of text have a color contrast difference of at least 3:1 with the surrounding text to ensure that users who cannot distinguish between the colors can still find the link.

When the link has no distinct style and it has a contrast difference of 3:1 or greater, you must manually test to verify that the link gets distinct style on focus and hover.

Compliance Data & User Impact

User Impact: Critical
Disabilities Affected:
  • Low Vision
  • Color-blindness
Issue Type:
  • WCAG 2.0 (A): SHOULD
  • Deque Experimental
WCAG Success Criteria:
  • 1.4.1 Use of Color
Section 508 Guidelines:
  • Not applicable

Related Deque University Course Pages

Other Related Resources

Additional Information

Relevant Technologies:
  • HTML 4
  • HTML 5
Test Reliability: Automated testing is possible, with high accuracy
Rule ID: link-in-text-block