To calculate the contrast ratio (CR), divide the luminance of the lighter color plus 0.05 by the luminance of the darker color plus 0.05.
The Contrast Ratio Calculator is a critical tool for assessing the visibility and accessibility of text, images, and UI elements. It helps designers and developers ensure compliance with standards like WCAG (Web Content Accessibility Guidelines), enhancing readability and usability for all users.
Formula
CR = (L₁ + 0.05) / (L₂ + 0.05)
| Variable | Description |
|---|---|
| CR | Contrast Ratio between two colors |
| L₁ | Relative luminance of the lighter color |
| L₂ | Relative luminance of the darker color |
Solved Calculations
Example 1: Contrast Ratio for Black and White
- L₁: 1 (White)
- L₂: 0 (Black)
| Step | Value |
|---|---|
| Add 0.05 to each luminance | , |
| Divide by | |
| Contrast Ratio | 21:1 |
Example 2: Contrast Ratio for Light Gray and Dark Gray
- L₁: 0.75
- L₂: 0.25
| Step | Value |
|---|---|
| Add 0.05 to each luminance | , |
| Divide by | |
| Contrast Ratio | 2.67:1 |
What is Contrast Ratio ?
The Contrast Ratio Calculator is a specialized tool used to measure the luminance difference between two colors. It is widely applied in web design, graphic design, and accessibility testing to ensure visual elements meet readability and accessibility standards, such as the Web Content Accessibility Guidelines (WCAG).
This calculator takes the relative luminance values of the foreground and background colors as input and computes their ratio. The resulting contrast ratio, expressed as a value like 4.5:1 or 7:1, determines whether the color combination meets WCAG Level AA or AAA requirements. For instance, text with a contrast ratio of 4.5:1 ensures sufficient visibility for normal-sized text.
In addition to web accessibility, the calculator is used in photography, display manufacturing, and other fields where color differentiation and clarity are crucial. It simplifies complex calculations, making it an essential resource for designers and developers alike.
Final Words:
Ultimately, the Contrast Ratio Calculator is a valuable tool for achieving color harmony and accessibility compliance. By enhancing clarity and readability, it fosters better user experiences across various platforms.
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