Contrast Ratio Calculator


Calculating contrast ratio is crucial for ensuring accessibility in web design. The contrast ratio between text and background colors impacts readability, especially for users with visual impairments. To simplify this process, a contrast ratio calculator can be a valuable tool. In this article, we'll discuss how to use such a calculator effectively.

How to Use

Using the contrast ratio calculator is straightforward. Simply input the hexadecimal values of the foreground (text) and background colors into the designated fields. The calculator will then compute the contrast ratio between these two colors, providing a numerical result.


The formula for calculating the contrast ratio between two colors is:


  • L1 is the relative luminance of the lighter color.
  • L2 is the relative luminance of the darker color.

The relative luminance of a color can be calculated using the formula:



  • R, G, and B are the red, green, and blue components of the color, respectively.

Example Solve

Suppose we have a text color with hexadecimal value #000000 (black) and a background color with hexadecimal value #FFFFFF (white).

Using the formula:

L black​=0.2126×0+0.7152×0+0.0722×0=0

L white​=0.2126×255+0.7152×255+0.0722×255≈255

Thus, the contrast ratio:


What is the significance of the contrast ratio in web design?

The contrast ratio determines the readability of text on a background, affecting the accessibility of content, especially for users with visual impairments.

How can I improve the contrast ratio of my website?

You can enhance the contrast ratio by choosing colors with greater luminance differences or by adjusting the brightness or saturation of colors.

Is there a minimum recommended contrast ratio for accessibility compliance?

Yes, the Web Content Accessibility Guidelines (WCAG) recommend a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text.


Incorporating a contrast ratio calculator into your web design workflow can significantly improve accessibility for all users. By ensuring adequate color contrast, you create a more inclusive online experience for everyone.

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