Color Tools

Color Contrast Checker

Test color combinations for WCAG accessibility compliance. Ensure your text is readable for everyone, including people with visual impairments or color vision deficiencies.

WCAG
Compliant
3
Levels
100%
Free

Color Contrast Checker

Test color combinations for WCAG 2.1 AA/AAA compliance

Accessibility Tool
Presets:
Presets:

Contrast Results

21.00
Contrast Ratio
1 4.5 (AA) 7 (AAA) 21
Normal Text (≥16px)
AAA
AA (4.5:1): Pass
AAA (7:1): Pass
Large Text (≥18px/14px bold)
AAA
AA (3:1): Pass
AAA (4.5:1): Pass
Graphical Objects
Pass
UI components, icons, charts
Requires 3:1 ratio

Color Information

Foreground: #333333
Background: #FFFFFF
Luminance (F): 0.06
Luminance (B): 1.00

WCAG 2.1 Accessibility Standards

AA

Level AA

Minimum requirement for most websites and applications.

  • Normal text: 4.5:1 contrast ratio
  • Large text: 3:1 contrast ratio
  • UI components: 3:1 contrast ratio
AAA

Level AAA

Enhanced accessibility for specialized audiences.

  • Normal text: 7:1 contrast ratio
  • Large text: 4.5:1 contrast ratio
  • Enhanced readability for low vision users

Text Size Definitions

Normal Text

Text smaller than 18 point (24px) or 14 point (18.67px) bold.

Large Text

Text at least 18 point (24px) or 14 point (18.67px) bold.

Graphical Objects

Icons, UI components, charts, and graphics.

Common Color Combinations

Black on White
21:1
Sample Text
Dark Gray on Light
12.6:1
Sample Text
Blue on White
6.2:1
Sample Text
White on Blue
6.2:1
Sample Text

Frequently Asked Questions

WCAG (Web Content Accessibility Guidelines) are international standards for web accessibility. Contrast ratio measures the difference in luminance between foreground (text) and background colors.

Proper contrast ensures that text is readable for people with visual impairments, color vision deficiencies, or those viewing screens in bright sunlight. It's essential for:

  • People with low vision or color blindness
  • Users viewing content on mobile devices in bright light
  • Older monitors with reduced contrast
  • Legal compliance in many countries

Contrast ratio is calculated using the relative luminance of the colors. The formula is:

(L1 + 0.05) / (L2 + 0.05)

Where L1 is the relative luminance of the lighter color and L2 is the relative luminance of the darker color.

Relative luminance is calculated based on how the human eye perceives different colors. The calculation accounts for the fact that our eyes are more sensitive to green light than red or blue.

AA Level AA

  • • Minimum requirement for most websites
  • • Normal text: 4.5:1 ratio
  • • Large text: 3:1 ratio
  • • UI components: 3:1 ratio
  • • Required for government and public sector sites

AAA Level AAA

  • • Enhanced accessibility standard
  • • Normal text: 7:1 ratio
  • • Large text: 4.5:1 ratio
  • • Best for audiences with visual impairments
  • • Recommended for health, education, banking

Most websites aim for AA compliance. AAA is recommended for sites serving audiences with visual impairments or in critical applications.

Yes! While WCAG primarily focuses on text readability, the 3:1 contrast ratio requirement also applies to graphical objects and user interface components:

  • Logos: Text within logos should have sufficient contrast
  • Charts & Graphs: Data points should be distinguishable
  • UI Components: Buttons, form fields, icons
  • Images of Text: Text in images should meet contrast requirements

Note: Decorative graphics without informational content don't require contrast compliance.