Free Color Contrast Checker — WCAG Accessibility Checker for Web Design

A color contrast checker verifies that your foreground and background color combinations meet WCAG accessibility standards. Enter any two colors to see their contrast ratio and whether they pass AA and AAA requirements for normal and large text.

Key Features

• WCAG Compliance Checking — Automatically evaluates contrast ratios against WCAG 2.1 AA and AAA standards
• Real-Time Preview — See how your colors look together with a live text preview showing different sizes
• Multiple Input Formats — Enter colors as HEX, RGB, or HSL values with instant conversion between formats
• Pass/Fail Indicators — Clear visual indicators showing whether each WCAG level is met
• Large Text Detection — Separate evaluation for normal text and large text thresholds
• Instant Results — See contrast ratio and compliance status as you type or pick colors

What is a Color Contrast Checker?

A color contrast checker is a free online tool that calculates the contrast ratio between two colors — typically a text color and its background — and evaluates whether the combination meets WCAG accessibility guidelines. It converts the colors to relative luminance values, computes the contrast ratio, and compares it against the minimum thresholds defined by WCAG 2.1 standards. For web designers, developers, and accessibility auditors, it is an essential tool for ensuring digital content is usable by people with visual impairments.

How to Use This Color Contrast Checker

Enter a foreground (text) color and a background color using HEX values (e.g., #333333 or #333). The tool instantly calculates the contrast ratio and displays whether the combination passes WCAG AA and AAA standards for both normal text and large text. A live preview shows how text appears against the background. Use the color picker inputs to visually select colors, or type values directly. Copy the contrast ratio or any color value with a single click.

Common Use Cases

• Web Designers — Verify color schemes during the design phase to ensure accessibility compliance from the start
• UI/UX Designers — Test interface elements like buttons, links, and form labels for sufficient contrast
• Accessibility Auditors — Include contrast checking as part of comprehensive accessibility evaluations
• Frontend Developers — Validate color combinations during implementation before code review
• Brand Designers — Ensure brand color palettes include accessible combinations for digital applications

Why Color Contrast Matters for Accessibility

Color contrast is one of the most common accessibility failures on the web. Low contrast text that looks perfectly fine on a designer’s high-end monitor can be illegible on a mobile screen outdoors, on a low-brightness display, or for a user with visual impairments. Ensuring sufficient contrast benefits all users, not just those with disabilities. High-contrast text reduces eye strain during extended reading sessions, improves readability on projectors and low-quality displays, and enhances the overall user experience. Beyond ethical considerations, many jurisdictions have legal requirements for digital accessibility, and contrast compliance is a fundamental component.

Best Practices for Color Contrast

• Always check contrast ratios during the design phase, not after implementation
• Maintain a contrast ratio of at least 4.5:1 for body text and 3:1 for large text (WCAG AA)
• Strive for 7:1 for body text and 4.5:1 for large text (WCAG AAA) when possible
• Never rely on color alone to convey information — use icons, patterns, or text labels in addition to color
• Test all interactive states including hover, focus, active, and disabled states
• Verify contrast for non-text elements like form borders, icons, and focus indicators
• Document accessible color combinations in your design system for consistent use across the organization

When to Use a Color Contrast Checker

Use a color contrast checker at every stage of the design and development process. During the design phase, check every color combination in your palette to identify problematic pairs before they are implemented. During development, verify that all interactive elements — buttons, links, form fields, focus indicators — have sufficient contrast in every state. Before launch, run a comprehensive accessibility audit that includes contrast checking across all page templates. For ongoing maintenance, check contrast whenever new design elements, brand colors, or third-party components are introduced. Consistent contrast verification prevents accessibility issues that would require expensive retrofitting later.