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.