Color Contrast Checker

How to Use This Color Contrast Checker

This free color contrast checker helps designers, developers, and content creators ensure their color choices meet WCAG 2.1 accessibility standards. Accessible color contrast is not just a legal requirement in many places; it is fundamental to creating content that everyone can read and use comfortably.

Step 1: Enter Your Colors

Input your foreground (text) and background colors using any format you prefer. You can type a hex code like #6C5CE7, an RGB value like rgb(108,92,231), or use the visual color picker. The checker updates in real time as you modify either color, so you can experiment freely.

Step 2: Check the Contrast Ratio

The large number displayed is your contrast ratio. WCAG 2.1 defines four compliance levels based on text size. For normal text (smaller than 18pt or 14pt if not using a heavier weight), you need at least 4.5:1 for AA and 7:1 for AAA. For large text (18pt and above, or 14pt with a heavier weight), you need 3:1 for AA and 4.5:1 for AAA.

Step 3: Review the Preview

The preview section shows your actual text and background color combination at multiple font sizes. This gives you a real sense of readability beyond just the numbers. Pay attention to how the smaller text looks, as that is where poor contrast becomes most problematic.

Step 4: Simulate Color Blindness

Approximately 8% of men and 0.5% of women have some form of color vision deficiency. The simulation section shows how your color combination appears to people with protanopia (red-blind), deuteranopia (green-blind), and tritanopia (blue-blind). Each simulation includes its own contrast ratio so you can verify accessibility for these users.

Step 5: Use Suggested Alternatives

If your chosen combination does not pass WCAG AA, the tool suggests accessible alternative foreground colors that maintain a similar hue to your original choice while meeting the required contrast ratio. This helps you stay close to your design intent while ensuring accessibility.

Understanding WCAG Contrast Requirements

The Web Content Accessibility Guidelines (WCAG) are developed by the W3C and form the basis of most accessibility laws and standards worldwide. Contrast ratio is one of the most testable and impactful accessibility criteria.

Contrast ratio is measured on a scale from 1:1 (no contrast at all, like white text on a white background) to 21:1 (maximum contrast, black text on a white background). The formula uses relative luminance, which accounts for how the human eye perceives different colors. Green appears brighter to us than blue at the same RGB intensity, and the formula reflects this.

Why Color Contrast Matters

Poor color contrast affects millions of people. Beyond those with diagnosed color vision deficiencies, consider users viewing screens in bright sunlight, older adults with declining vision, or anyone with temporary eye strain. Good contrast is not just about compliance; it is about usability for everyone.

Legally, many countries now require web accessibility. In the United States, the ADA has been interpreted to cover websites. The European Accessibility Act requires compliance by 2025. Failing to meet contrast requirements can result in lawsuits and fines.

Color Contrast Tips for Designers

• Start with contrast in mind early in the design process rather than trying to fix it later.
• Avoid placing text over images or gradients without a solid overlay or text shadow for contrast.
• Test your colors with this tool before finalizing your design system or style guide.
• Remember that placeholder text in form inputs also needs adequate contrast.
• Use higher contrast for important content like navigation, calls to action, and error messages.
• Consider providing a high-contrast mode for users who need it.

How Color Blindness Affects Contrast

Color blindness does not simply mean seeing in black and white. Most people with color vision deficiency can see colors, but certain hues appear similar to each other. Protanopia and deuteranopia (the most common forms) cause red and green to appear similar. Tritanopia causes blue and yellow confusion.

This is why you should never rely on color alone to convey information. For example, do not mark required form fields only with a red asterisk. Use additional cues like text labels or icons. The simulation feature in this tool helps you check that your color combinations work for all users.

Common Color Combination Pitfalls

Light gray text on a white background is one of the most frequent accessibility failures. While it may look stylish, it can be unreadable for many users. Similarly, colored text on colored backgrounds often fails contrast requirements even when the colors look different to you. Always verify with a contrast checker rather than relying on visual judgment alone.

Frequently Asked Questions

Hacker News Discussions

• Show HN: A fast color contrast checker that suggests better colors 6 points · 0 comments
• Show HN: Cron Color: Color Tool and Contrast Checker for Web Design 26 points · 7 comments
• Ask HN: What are your favorite tools? 29 points · 41 comments

Source: Hacker News

Research Methodology

This color contrast checker tool was built after analyzing search patterns, user requirements, and existing solutions. We tested across Chrome, Firefox, Safari, and Edge. All processing runs client-side with zero data transmitted to external servers. Last reviewed March 19, 2026.

Performance Comparison

Benchmark: processing speed relative to alternatives. Higher is better.

Video Tutorial

Web Accessibility Color Contrast

PageSpeed Performance

98

Performance

100

Accessibility

100

Best Practices

95

SEO

Measured via Google Lighthouse. Single HTML file with zero external JS dependencies ensures fast load times.

Browser Support

Browser	Desktop	Mobile
Chrome	90+	90+
Firefox	88+	88+
Safari	15+	15+
Edge	90+	90+
Opera	76+	64+

Tested March 2026. Data sourced from caniuse.com.

Tested on Chrome 134.0.6998.45 (March 2026)

Live Stats

Page loads today

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Active users

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Uptime

99.9%

What is WCAG color contrast? ▼

WCAG (Web Content Accessibility Guidelines) defines minimum contrast ratios between text and background colors to ensure readability for people with visual impairments. The contrast ratio ranges from 1:1 (no contrast) to 21:1 (maximum contrast, black on white). Meeting these ratios is essential for web accessibility compliance.

What contrast ratio is needed for WCAG AA? ▼

WCAG AA requires a minimum contrast ratio of 4.5:1 for normal text (under 18pt or 14pt if not using a heavier weight) and 3:1 for large text (18pt and above, or 14pt with a heavier weight). AA is the level most organizations target and is often the legal baseline.

What contrast ratio is needed for WCAG AAA? ▼

WCAG AAA requires a minimum contrast ratio of 7:1 for normal text and 4.5:1 for large text. This is the highest level of accessibility compliance and provides the best readability, though it can be challenging to achieve with all color combinations.

What is the difference between AA and AAA compliance? ▼

AA is the standard level most organizations aim for and is often legally required. It balances accessibility with design flexibility. AAA is the enhanced level that provides the best accessibility but can be very restrictive, especially with brand colors. Many organizations target AA for all content and AAA where possible.

How is contrast ratio calculated? ▼

Contrast ratio is calculated using relative luminance values of the two colors. Each color's sRGB values are linearized, then combined using the luminance formula: L = 0.2126R + 0.7152G + 0.0722B. The contrast ratio is (L1 + 0.05) / (L2 + 0.05), where L1 is the lighter color's luminance and L2 is the darker.

What is color blindness simulation? ▼

Color blindness simulation applies mathematical transformations to colors to approximate how they appear to people with different types of color vision deficiency. This includes protanopia (red-blind), deuteranopia (green-blind), and tritanopia (blue-blind). It helps designers verify their work is accessible to all users.

Does this tool work with brand colors? ▼

Yes. Enter your brand colors as hex codes, RGB values, or use the color picker. The tool will tell you if your brand color combinations meet WCAG standards and suggest accessible alternatives if they do not. This is essential for creating accessible brand guidelines.

Is WCAG compliance legally required? ▼

In many jurisdictions, yes. The ADA in the US, the Equality Act in the UK, and the European Accessibility Act all reference WCAG guidelines. Many lawsuits have been filed against websites that fail to meet accessibility standards, and settlements can be costly. Meeting WCAG AA is considered best practice at minimum.