Colour Contrast Analyzer (CCA)

Use TPGi's free colour contrast checker to optimize your content - including text and visual elements - for individuals with color-blindness or low vision impairments. Current version 3.5.2

One Colour Contrast Tool for All Your WCAG Color Checking Needs

Desktop computer monitor displaying text Contrast Failure with the Colour Contrast Analyzer checking for the color contrast ratio.

The colour contrast checker can be used on websites, during app development, designing social media graphics, PowerPoint slides, PDFs, InDesign files, and almost anything!


  • Compliance indicators for WCAG 2.1
  • Dark Mode
  • Multiple ways to select colors: You can manually enter CSS color formats, use an RGB slider, or opt for the color picker tool
  • Color Blindness Simulator
  • Support for alpha transparency
    on foreground colors

Go Beyond Color, Design Inclusive User Experiences

Continue your accessibility journey and explore additional UX and inclusive design resources below.


Create Inclusive UX

Improve your UX accessibility knowledge with our blog series and learn how to connect accessibility with user experience to create inclusive digital products.

Get the UX Resources

Common Web Accessibility Issues

Ten Common Web Accessibility Issues

If you are just starting your digital accessibility journey, start by reviewing some common accessibility issues.

Top accessibility issues

Design Webinar

A Guide to Inclusive Design

Learn about usability, accessibility, inclusive design, and practical tips that everyone can use to make usable and accessible digital experiences.

Inclusive Design Webinar


AT User Flow Testing

Ensure you created a usable experience for assistive technology users with AT User Flow Testing.

AT User Flow Testing

Learn more about WCAG Color Contrast

The Web Content Accessibility Guidelines (WCAG) define the different levels of contrast rations depending on the level of success criteria. Below is helpful information for comparing the results of our tool to the level of success criteria you hope to achieve.

WCAG 2.0 Level AA

This level requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text.

WCAG 2.1/2.2 Level AA

This level requires a contrast ratio of at least 3:1 for graphics and user interface components.


This level requires a contrast ratio of at least 7:1 for normal text and 4.5:1 for large text.

Additional Color Contrast Analyzer Information

Support and Development

Have a question about the Colour Contrast Analyzer or discovered a bug?

Visit TPGi’s CCA repository on GitHub

End User License Agreement (EULA)

Review the EULA by visiting our GitHub page.

Previous Versions

The current version of the Colour Contrast Analyzer (CCA) has been rebuilt from the ground up using Electron. For the previous, non-Electron versions (“CCA Classic”), see the CCA-Win and CCA-OSX repositories.

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.