Color contrast ratio measures the contrast between the color of text and the color on which it sits.

For AA compliance for unlinked text, WCAG requires at least a 4.5:1 color contrast ratio for normal-sized text and a 3:1 color contrast ratio for larger text.

24px or larger. If the text is bold, then 18.66px or larger. Beyond that, look at your text and ensure it is easy to read, not simply "able to be read." Have a person with low vision test your site and get feedback.

Many organizations use color to distinguish their links from the surrounding text. The color contrast is not as critical if you use other ways to distinguish your links from the text (bold, underline, etc. - which is recommended).

However, color alone is NOT an accurate way to distinguish a link from the text around it. However, contrast alone, can be used. Your links must maintain a 3:1 contrast from the surrounding text, while still meeting the guidelines above for the ratio between the text and the background.