Online Color Accessibility Checker

The Online Color Accessibility Checker analyzes a foreground/background color pair and returns a contrast ratio and compliance status against WCAG 2.1/2.2 targets. It is intended for designers, front-end engineers, accessibility specialists, and product teams who need objective validation during color selection and theming. The tool accepts color inputs in hex or named colors and outputs a numeric contrast result along with a pass/fail verdict and guidance.
Internally, the tool performs the standard WCAG contrast calculation. It converts colors to linear light values using sRGB gamma correction, computes luminance, and derives the contrast ratio with the formula (L1+0.05)/(L2+0.05), where L1 is the lighter color. The calculation is deterministic and device-agnostic, ensuring consistent results in design reviews and code reviews.
Who benefits includes product teams shipping accessible interfaces, designers refining brand palettes, developers implementing CSS with accessibility in mind, and QA teams documenting compliance. The value lies in precise numeric results, clear pass/fail criteria, recommended alternative colors, and ready-to-export reports that can feed design systems and style guides.
Core features include input validation, configurable target ratios, automatic suggestions for accessible alternatives, and concise outputs suitable for UI documentation. Use cases cover body text color on hero backgrounds, dark mode palette evaluation, and ensuring accessible call-to-action colors in marketing pages.