Colour Blindness Simulator
Simulate how your colours look to people with different types of colour blindness.
Seeing colour as others do
Colour blindness affects a significant share of people, most commonly making certain colours — especially reds and greens — hard to tell apart. This simulates how your colours and designs look under different types of colour vision deficiency, so you can catch combinations that fail for a meaningful part of your audience.
Add your colours or image to see them simulated.
Why designing for it matters
The reason this check is worth doing is that colour blindness is common enough — affecting roughly one in twelve men — that ignoring it excludes real users, and the failures are invisible to designers with typical vision. The classic trap is conveying information by colour alone: a red-and-green status indicator that looks identical to someone with the most common deficiency, a chart whose lines are only distinguished by colour. The fix is not to avoid colour but to never rely on it alone — add labels, icons, patterns or text so the meaning survives without the colour. Simulating your design is how you find those failures before your users hit them, and it makes what you build usable for far more people.
Questions & answers
How common is colour blindness?
Common enough to matter — roughly one in twelve men — and its most frequent form makes reds and greens hard to distinguish.
What is the main design mistake it reveals?
Conveying information by colour alone, like a red-green status indicator. The fix is to add labels, icons or patterns so meaning survives without colour.
Is my image uploaded?
No. The simulation happens in your browser.