To ensure text is perceivable, there must be sufficient contrast between the text color and background color. Contrast is measured by the difference in perceived brightness of two colors, commonly referred to as its “contrast ratio.” WCAG 2.1 level AA requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text.
This tool allows users to enter a foreground and background color to check if it meets WCAG requirements. It also allows users the option to choose a color using the "Color Picker Eyedropper" to extract color values from any element on the screen.
You can also install the Contrast Checker Bookmarklet (opens in new window) in your browser’s Bookmarks bar to easily access the Contrast Checker.
Note: The Color Picker Eyedropper is not supported in Firefox.