Contrast Checker
Ensure your typography passes official WCAG 2.1 Level AA and AAA accessibility requirements with real-time text simulation.
Accessibility Drives Human Usability
WCAG 2.1 requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text to ensure content is legible for people with visual impairments.
100% Local Browser Privacy
All computation happens right in your browser's JavaScript engine. No data is ever sent to any remote server.
Instant Results
Zero network latency. Calculations and formatting are executed instantly with high cryptographic and mathematical precision.
Works Offline
Once loaded, this tool can function completely offline with no active internet connection required.
Frequently Asked Questions
What is the minimum WCAG AA ratio?
4.5:1 for normal text (under 18pt), and 3.0:1 for large text (18pt+ or 14pt bold).
What is Level AAA?
The highest standard of web accessibility, requiring at least 7.0:1 for normal text.