Color Blindness Simulator
Your image or palette through protanopia, deuteranopia, tritanopia, and achromatopsia — side by side, entirely on your device.
How to use this tool
- Choose an image (a UI mockup, chart, or map works especially well) — it stays on your device, which matters for unreleased designs.
- Compare the original against the four simulations side by side.
- If information disappears in any panel — a chart series, a status color, a link — add a second cue: labels, patterns, icons, or underlines.
How it works
Each simulation transforms every pixel with a widely used color-matrix approximation of how the image appears with that type of dichromacy: protanopia (no red cones), deuteranopia (no green cones — the most common, affecting about 1 in 12 men), tritanopia (no blue cones, rare), and achromatopsia (no color at all, very rare). These are approximations — real color vision deficiency varies in degree — but they reliably reveal the failure that matters: two colors you meant as different becoming the same.
The fix is never 'better colors' alone: it's redundancy. WCAG's use-of-color rule (SC 1.4.1) says color can't be the only way information is conveyed — the simulator shows you where that rule is being broken.
Sources & references
Content last reviewed: July 2026.
Frequently asked questions
How common is color blindness?
Roughly 1 in 12 men and 1 in 200 women have some form — red-green types are by far the most common. For a site with any real traffic, that's a meaningful slice of visitors.
How accurate are the simulations?
They're standard matrix approximations of full dichromacy — good for spotting problems, not medical instruments. Real deficiency is often partial (anomalous trichromacy), meaning the real-world effect sits between the original and the simulation.
My chart colors look identical in a panel — what do I do?
Add a non-color cue: direct labels, different line/marker styles, patterns in bars, icons on statuses. Also check the pair in our Contrast Checker — luminance difference survives color blindness.