WCAG contrast checker tools are essential for building accessible interfaces that meet legal and usability standards. This free, browser-based tool calculates the exact contrast ratio between two colors and reports pass or fail status for WCAG 2.1 AA and AAA levels for both normal and large text. No signup needed. Quickly audit any color combination in your design system.
Contrast Checker is a free browser-based tool that calculates the contrast ratio between two colors and reports whether the combination passes WCAG (Web Content Accessibility Guidelines) accessibility standards. WCAG defines minimum contrast ratios for text readability: 4.5:1 for normal-sized text at the AA conformance level and 7:1 for the AAA (enhanced) level. Large text (18pt or 14pt bold) has lower thresholds of 3:1 for AA and 4.5:1 for AAA. Low contrast makes text difficult or impossible to read for users with visual impairments, including those with low vision or color vision deficiencies. This tool accepts foreground and background colors in HEX or RGB, calculates the contrast ratio, and displays a clear pass or fail result for each WCAG level. It is an essential tool for web designers and front-end developers building accessible interfaces. No account or installation is required.
Contrast Checker is used most actively during the visual design and CSS implementation phases of a web project, when color choices are being finalized for text, buttons, labels, form fields, and interactive elements. The WCAG contrast requirements apply to any text that communicates information, including body text, headings, placeholder text, button labels, navigation links, and form labels. They also apply to user interface components and graphical elements that carry meaning. Decorative elements and logos are exempt. A common workflow is to use Contrast Checker to validate every foreground-background color pair in a design system's color palette before development begins, so that any failing combinations can be adjusted while changes are still easy to make. Passing AA is a legal requirement under accessibility laws in many jurisdictions, including the UK Equality Act, the US Rehabilitation Act Section 508, and the EU Web Accessibility Directive. AAA is a best-practice target for body text that significantly improves readability for users with low vision. When a combination fails, the typical fix is to darken the foreground color or lighten the background color until the ratio crosses the threshold. Color Converter is useful alongside Contrast Checker for adjusting the lightness of a color in HSL format and then copying the corrected HEX value. The tool runs free in the browser without installation.