Colour Contrast Analyser

The Colour Contrast Analyser (CCA) helps you determine the legibility of text and the contrast of visual elements, such as graphical controls and visual indicators.

This tool provides two useful core functionalities:

  1. a pass/fail assessment against WCAG 2.0 color contrast success criteria
  2. a simulation of certain visual conditions, including dichromatic color-blindness and cataracts, to demonstrate how your web content appears to people with less than 20/20 vision

The CCA is available for Windows and Mac, and in multiple languages including English, French, Dutch, Italian, German, Hindi, Korean and traditional Chinese. Note: the visual simulation functionality is only available in the Windows version.


The Colour Contrast Analyser was developed by JUn in collaboration with Steve Faulkner (The Paciello Group, Europe). Mac version developed by Cédric Trévisan (The Paciello Group, Europe).

A prior version of the CCA was partially funded by the Trace Research and Development Center as part of the NIDILRR Funded Rehabilitation Engineering Research Center (H133E030012)

Support and development

For questions concerning the Colour Contrast Analyser (CCA), or to report bugs, suggest improvements, contribute to the code, see the repositories for Colour Contrast Analyser (CCA) for Windows and Colour Contrast Analyser (CCA) for macOS / OS X. Alternatively, you can email us at

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.