ColorContrast.App

The color contrast checker is an online resource designed to evaluate the contrast and accessibility of various color combinations in accordance with WCAG or APCA standards. It also allows users to simulate different types of color blindness. How does the color contrast checker function? The Polypane color contrast checker assesses colors based on the criteria set forth by WCAG 2 (Web Content Accessibility Guidelines) or APCA (the Accessible Perceptual Contrast Algorithm). WCAG provides a formula to determine contrast, which ranges from 1 (no contrast) to 21 (black on white). APCA operates on a scale from approximately -106 to +106. The Polypane contrast checker considers opacity in its calculations, providing an accurate contrast ratio. How are the recommended colors determined? If the contrast is inadequate, we will suggest alternative colors that offer sufficient contrast. This is achieved by adjusting the luminance of the foreground color until it meets the necessary contrast requirements. If the foreground color cannot be altered (due to being too close to pure black or pure white), we will recommend an accessible background color instead.