How to use this developer tool
Compare two colors and see the contrast ratio with common WCAG AA and AAA pass/fail guidance.
How the processing works
- Converts HEX colors to relative luminance.
- Calculates the contrast ratio.
- Shows AA and AAA results for normal and large text guidance.
Example
Check whether dark text on a light background has enough contrast before using it in a design.
Using the output
Use the output as a practical starting point, then review it before using it in an important workflow.
Assumptions and limitations
- Contrast alone does not guarantee full accessibility.
- SERP, social, and browser rendering can still vary by device and user settings.
Frequently asked questions
Does this require an account?
No. The core tool works without creating a Tool2Do account.
Is my input included in share links or analytics?
No. Tool2Do share actions use the tool page URL and safe metadata, not private values or uploaded files.