Color blindness simulator
Upload an image and see it through the eyes of someone with protanopia, deuteranopia, or tritanopia, essential for checking that your graphics, maps, and interfaces are accessible.
JPG, PNG, WebP, or GIF, everything stays on your device
What are protanopia, deuteranopia, and tritanopia?
They are the three main forms of color blindness: protanopia means the red photoreceptors are missing, deuteranopia the green ones (the most common form), and tritanopia, far rarer, the blue ones. The first two affect roughly 8% of men and 0.5% of women: on a site with a thousand visitors, dozens of people may be unable to tell a red button from a green one. This tool applies the color-conversion matrices used in color vision research to every pixel of your image, giving you a realistic preview of how your design actually looks to them.
How to design graphics that work for color-blind users
The golden rule: never rely on color alone to convey information. In charts, add labels, patterns, or distinct shapes; in forms, flag errors with an icon and a message, not just a red border; in links, keep the underline. The most problematic pairs are red/green and blue/purple: if two nearby elements become indistinguishable after simulation, increase the brightness contrast or change one of the two hues. The quickest sanity check: if your image still works in black and white, it will work for everyone.