Sufficient contrast makes your text and UI elements readable for everyone — especially users with low vision or color blindness. WCAG recommends a minimum ratio of 4.5:1 for normal text and 3:1 for large text.
What is Sufficient Contrast?
Sufficient contrast refers to the difference in luminance or color that makes an object distinguishable from other objects and the background. In the context of user interfaces, it ensures that text and interactive elements are easily readable and accessible to all users, including those with visual impairments.
Why is Sufficient Contrast Important?
Sufficient contrast is vital for accessibility as it ensures that users with visual impairments, such as color blindness or low vision, can read and interact with content effectively. Poor contrast can lead to eye strain and make it difficult for users to navigate and understand information, ultimately excluding them from using your application.
How to Measure Contrast
Contrast is typically measured using a contrast ratio, which compares the luminance of the foreground (text or element) to the background. The Web Content Accessibility Guidelines (WCAG) recommend a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text.
Pro tip: My app iWebTools has a built-in contrast checker that you can use to evaluate the contrast ratios of your color choices.
Contrast checker
| Ratio |
| Normal Text Example |
| Large Text Example |
| ★ UI Component Example |
Wrap up
Getting contrast right is one of the more impactful accessibility improvements you can make — and it benefits everyone, not just users with visual impairments.
Resources: