Free Accessibility Tools

About these tools

Roughly one in twelve men has a color vision deficiency, low vision becomes near-universal with age, and every visitor benefits from readable text — accessibility is mainstream engineering, not an edge case. These tools cover the checks designers and developers run most: exact WCAG 2.2 contrast ratios for a color pair or a whole palette, color-blindness simulation for images and palettes, readability scoring for plain language, and the px-to-rem conversion behind scalable text.

Everything runs on your device, which matters more here than usual: the color-blindness simulator accepts unreleased UI mockups and confidential documents precisely because they're never uploaded anywhere.

We hold ourselves to the same standards — this site ships with a skip link, visible keyboard focus, screen-reader announcements on results and errors, reduced-motion support, and text contrast we verified with these very tools.

Start with the Contrast Checker when you have one foreground and one background color to validate, and the Palette Contrast Checker when you need every combination in a palette scored at once — it catches the pairings a designer would never think to test individually. The Color Blindness Simulator answers a different question: not whether text is readable, but whether a chart, status color, or interface still communicates when hue information is missing. The Readability Analyzer scores the language itself against Flesch Reading Ease and grade level, which is the accessibility criterion teams most often forget. The px-to-rem Converter is the tooling behind scalable type — the conversion you need to stop hard-coding font sizes that ignore a user's browser settings.

Frequently asked questions