Contrast Checker
Calculate foreground/background relative-luminance contrast and show WCAG AA/AAA pass states.
How to use
- Enter foreground and background HEX colors and inspect the live sample and status grid.
Capabilities and scope
contrastRatio is compared with 4.5 for AA normal text, 3 for AA large text, and 7 for AAA normal text.
How it works
sRGB colors are converted to relative luminance and the standard (Llighter+0.05)/(Ldarker+0.05) ratio is used.
Example
Black #000000 against white #FFFFFF reports 21:1.
Useful for
- Check basic accessibility contrast for text or button colors
Before you use it
- Font size, weight, states, non-text contrast, and the rest of WCAG conformance are outside this single ratio check.
Standards and references
Frequently asked questions
What is the AA normal-text threshold?
The current tool marks 4.5:1 or higher as passing AA normal text.