Contrast Ratio Checker – Free WCAG Accessibility Tool

How to Use the Contrast Ratio Checker

Enter Your Foreground and Background Colors — Type in your foreground (text) and background colors using a hex code (e.g., #FFFFFF) or RGB values, or use the built-in color picker to select your colors visually. Both fields must be filled before the checker calculates your result.

Calculate the Contrast Ratio Instantly — Click the Check Contrast button and the tool instantly computes the luminance of both colors and returns a precise contrast ratio. Results are displayed in real time, showing the exact ratio value alongside clear WCAG AA and AAA pass or fail indicators.

Review Results and Adjust Your Colors — Review whether your color combination passes WCAG 2.1 Level AA or AAA thresholds for normal and large text. If it fails, adjust your colors and retest until you achieve compliance. Repeat for as many color pairs as your design requires — unlimited and free.

Check the live preview to see how the text looks at normal and large sizes

About This Contrast Ratio Checker

Color contrast is one of the most critical factors in web accessibility. When text does not stand out clearly from its background, users with low vision, color blindness, or age-related visual impairments can struggle to read your content. The ToolCentrix Contrast Ratio Checker is a free online tool that instantly calculates the contrast ratio between any foreground and background color, helping developers, designers, and content creators build more inclusive digital experiences — no account or download required.

The tool tests your color combinations against the Web Content Accessibility Guidelines (WCAG 2.1 and WCAG 2.2), the globally recognized standard for digital accessibility. According to the W3C, normal text must achieve a contrast ratio of at least 4.5:1 for WCAG Level AA compliance and 7:1 for the stricter Level AAA standard. Large text (18pt or 14pt bold) requires a minimum ratio of 3:1 for AA and 4.5:1 for AAA. Our checker instantly displays a clear pass or fail result for both levels, so you know exactly where your design stands.

Whether you are building a website, SaaS dashboard, mobile app, or digital document, meeting WCAG contrast requirements is not just a best practice — it is increasingly a legal obligation. In the United States, the ADA and Section 508 both reference WCAG standards for web accessibility compliance. In Australia, the Disability Discrimination Act (DDA) and the Australian Government's Digital Service Standard align closely with WCAG 2.1 AA requirements. Globally, organizations are adopting these standards to ensure equal access for all users, regardless of ability.

Using the ToolCentrix Contrast Ratio Checker is straightforward. Simply enter your foreground (text) color and background color using hex codes, RGB values, or the built-in color picker. The tool instantly computes the luminance of each color and calculates the precise contrast ratio, displaying whether your combination passes or fails WCAG AA and AAA thresholds. You can test unlimited color combinations in seconds, making it ideal for rapid design iteration and accessibility audits.

This free color contrast checker is trusted by web developers, UX/UI designers, accessibility consultants, and QA testers across the USA, Australia, India, and beyond. It is particularly valuable during design reviews, client presentations, and accessibility audits where quick, reliable contrast verification is essential. Unlike some tools that require a login or software installation, ToolCentrix works entirely in your browser with zero friction.

ToolCentrix is committed to your privacy. This contrast ratio checker runs entirely client-side — no color data, hex codes, or inputs are ever stored, transmitted, or shared with third parties. It is completely free to use with no usage limits, no ads blocking your workflow, and no registration required. Start checking your color contrast ratios today and build websites that are accessible to everyone.

Frequently Asked Questions

A color contrast checker ensures your text and UI elements are readable by all users, including those with low vision or color blindness. It verifies compliance with WCAG 2.1 and 2.2 standards, helping you avoid accessibility barriers, reduce legal risk under laws like the ADA and Australia's DDA, and deliver a better user experience across all devices and audiences.

WCAG Level AA requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text — this is the standard most websites and legal frameworks target. Level AAA is stricter, requiring 7:1 for normal text and 4.5:1 for large text. AAA compliance offers the highest level of readability for users with significant visual impairments.

The minimum contrast ratio required by WCAG 2.1 for Level AA compliance is 4.5:1 for standard body text and 3:1 for large text (18pt regular or 14pt bold). For Level AAA, the minimums increase to 7:1 and 4.5:1 respectively. These ratios measure the relative luminance difference between foreground and background colors.

The WCAG Contrast Checker evaluates any foreground and background color combination, including body text, headings, buttons, links, form labels, icons with text, and UI components. It calculates luminance-based contrast ratios for hex and RGB colors. Note that purely decorative elements and logos are generally exempt from WCAG contrast requirements under the guidelines.

No — passing a color contrast test is an important step, but full accessibility requires much more. WCAG compliance also covers keyboard navigation, screen reader compatibility, proper heading structure, alternative text for images, focus indicators, and more. Use the contrast checker alongside a broader accessibility audit to ensure your site meets WCAG 2.1 or 2.2 standards comprehensively.