Question 1

How is the contrast ratio calculated?

Accepted Answer

The contrast ratio is calculated using a formula provided by the World Wide Web Consortium (W3C) in their Web Content Accessibility Guidelines (WCAG). This formula measures the difference in perceived 'lightness' or luminance between the foreground and background colors. A higher ratio means better visibility. Our tool automates this calculation for you, giving you an instant result.

Question 2

What's the difference between WCAG AA and AAA?

Accepted Answer

WCAG defines two main levels of contrast compliance: AA and AAA. Level AA is the minimum standard for accessibility and is a legal requirement in many jurisdictions. It requires a contrast ratio of at least 4.5:1 for normal text. Level AAA is an enhanced standard that requires a higher ratio of 7:1, making content accessible to a wider range of users with low vision. For large text (18pt or 24px and larger), the ratios are 3:1 for AA and 4.5:1 for AAA.

Contrast Checker

How to Use the Tool

Frequently Asked Questions