WCAG Color Contrast Checker
Test foreground and background color combinations against WCAG 2.1 Level AA and AAA accessibility requirements.
WCAG 2.1 Color Contrast Ratio Checker
Test foreground and background color combinations against WCAG Level AA and AAA accessibility standards.
Simulated Sample Preview
This interactive box demonstrates how your selected text color looks against the background color. Clear contrast ensures readability for low-vision users and under bright sunlight.
Understanding WCAG 2.1 Color Contrast Standards
Digital accessibility is essential for creating inclusive web applications and complying with legal standards such as the Americans with Disabilities Act (ADA) and Section 508.
WCAG Thresholds Summary
- Level AA (Normal Text): Minimum 4.5:1 contrast ratio.
- Level AA (Large Text 18pt+): Minimum 3.0:1 contrast ratio.
- Level AAA (Normal Text): Minimum 7.0:1 enhanced contrast ratio.
Accessibility Applications
- ✓Design System & UI Component Accessibility
Ensure primary buttons, badges, links, and input field borders pass ADA and Section 508 legal compliance.
- ✓Dark Mode Color Theme Audits
Verify that muted secondary text and subtle borders maintain legible 4.5:1 contrast against dark background canvases.
- ✓Government & Enterprise Website Auditing
Satisfy strict public sector accessibility guidelines requiring mandatory WCAG 2.1 Level AA certification.
- ✓Brand Identity & Palette Verification
Test primary corporate brand colors against white and dark backgrounds before finalizing marketing design guidelines.
Key Checker Features
Exact WCAG 2.1 Relative Luminance Algorithm
Calculates perceived brightness using the official W3C color luminance formula `((L1 + 0.05) / (L2 + 0.05))`.
Pass/Fail Badges for Normal & Large Text
Displays explicit status for Level AA (4.5:1), Level AAA (7.0:1), and UI Components / Large Text (3.0:1).
Real-Time Preview Canvas
Inspect how body typography and headline text appear in real time directly inside an active preview block.
1-Click Color Swapper
Instantly invert foreground and background colors to evaluate both light and dark variations.
Frequently Asked Questions
What is the WCAG Level AA contrast requirement?
For normal text (under 18pt or 14pt bold), WCAG Level AA requires a minimum contrast ratio of 4.5:1. For large text (18pt+ or 14pt+ bold), the minimum ratio is 3.0:1.
What is the WCAG Level AAA contrast requirement?
Level AAA is the enhanced accessibility standard. It requires a minimum contrast ratio of 7.0:1 for normal text and 4.5:1 for large text.
Why is color contrast important for web design?
Adequate color contrast ensures content is legible for people with visual impairments, color blindness, or low contrast sensitivity, as well as users viewing screens outdoors under direct sunlight.
Do placeholder texts inside inputs need to pass WCAG?
While WCAG 2.1 focuses on active text and essential UI controls, accessible design best practices strongly recommend that placeholder text and help labels meet at least 3.0:1 contrast so users can easily read input instructions.
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