Colour-Blindness Simulator
Charts that rely on red-versus-green, warning icons distinguished only by hue, text on a coloured background — colour-vision deficiency quietly breaks all of them for millions of users. This simulator renders your image through the published Machado, Oliveira & Fernandes (2009) matrices for seven vision types, so you can see exactly what survives and export the simulation for design reviews.
Drop an image to check how it looks with colour-vision deficiency
JPG, PNG, WebP, AVIF, GIF, BMP, TIFF, HEIC or SVG — processed locally, never uploaded · You can also paste from the clipboard
How to colour-Blindness Simulator
- Drop the image (design, chart, photo).
- Step through the vision types — start with deuteranopia, the most common.
- Where meaning disappears, add labels, patterns, icons or brightness contrast.
Frequently asked questions
How accurate is the simulation?
It uses the standard physiologically-based matrices used across the industry for the -opia types at full severity and the -omaly types at 0.6 severity. Individual vision varies, but as a design check ("does the meaning survive?") it is the accepted approach.
What is the most common deficiency?
Deuteranomaly/deuteranopia (green) then protan defects (red) — together roughly 8% of men and 0.5% of women. Tritan (blue) defects are rare and usually acquired.