How it works
Enter the foreground text color and background color as HEX, RGB or HSL. Read the contrast ratio and the live text sample. Check normal-text AA and AAA indications separately. Check large-text indications only for text at least 18pt, or 14pt bold. Swap the colors or adjust them, then review contrast in the actual page context. AA requires 4.5:1 for normal text and 3:1 for large text. AAA requires 7:1 and 4.5:1 respectively. Pass/fail uses the unrounded ratio, while the displayed value has two decimals. Transparent foreground is composited over the background; a transparent background is composited over white. This checks two colors, not gradients, images, focus behavior or the accessibility of an entire website.
Interpret results and limitations
AA requires 4.5:1 for normal text and 3:1 for large text. AAA requires 7:1 and 4.5:1 respectively. Pass/fail uses the unrounded ratio, while the displayed value has two decimals. Transparent foreground is composited over the background; a transparent background is composited over white. This checks two colors, not gradients, images, focus behavior or the accessibility of an entire website.
Example
Use this example to understand the expected behavior before working with your own input.
Black on white: 21:1
White on white: 1:1Continue your task
Color Picker & Converter — Continue with this related local tool.
Image Resizer — Continue with this related local tool.
Frequently asked questions
A ratio near the threshold seems inconsistent?
The display is rounded to two decimals. The indication uses the full calculated ratio; choose a margin above the threshold.
Is my input uploaded or stored?
No. Processing and results stay in this tab. There is no input history or server processing. Copy and download are explicit actions.
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