WCAG Contrast Checker
Check the contrast between text and background colors against WCAG AA and AAA thresholds.
Description
Check text and background colors against WCAG AA and AAA contrast thresholds.
WCAG Contrast Checker is a focused tool for the following task. Check text and background colors against WCAG AA and AAA contrast thresholds. It reports WCAG contrast result from the values you provide rather than inventing measurements, coefficients, or professional judgment that are not part of the input.
When to use WCAG Contrast Checker
Use this checker to test a specified foreground and background color pair against the stated WCAG contrast thresholds for text.
- Foreground color
- Required string.
- Background color
- Required string.
The cited overview of Web Content Accessibility Guidelines supplies background for the terminology and domain context used by this tool.1
How WCAG Contrast Checker works
Check text and background colors against WCAG AA and AAA contrast thresholds. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.
- WCAG contrast result
- Returned object.
Limitations and assumptions
- A passing ratio does not establish overall accessibility and does not cover font rendering, images, focus visibility, non-text contrast, state changes, or the rest of the WCAG success criteria.
- Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.
Alternative or Complementary approaches
Test the complete interface with automated checks, keyboard navigation, zoom, high-contrast settings, and representative assistive technologies.
References
-
Web Content Accessibility Guidelines — Wikipedia contributors
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