Color Blindness Simulator
See how an image looks to people with different kinds of colour blindness, so you can check your design works for everyone.
Designing for colours you cannot rely on
Around one in twelve men and one in two hundred women has some form of colour vision deficiency, most often trouble telling red from green. A chart, a map, a status light or a button that relies on colour alone can be unreadable to them. This re-renders your image the way it would appear under the main types of colour blindness, so you can spot the problems before you ship.
Deuteranopia and protanopia affect red-green perception; tritanopia affects blue-yellow. Flicking through them shows where a design leans too hard on colour.
The fix is usually not more colour
If two things differ only by colour and that difference disappears in the simulation, the answer is not a brighter colour — it is another cue. Labels, patterns, icons or different shapes carry meaning that survives whatever the viewer can or cannot distinguish. Colour should reinforce the message, not be the only thing carrying it.
How to simulate colour blindness
- Add your image or design.
- Switch between the types of colour vision deficiency.
- Check that everything still reads, and download the simulation.
Designing for one in twelve men
Around 8% of men and 0.5% of women have some form of colour vision deficiency, most commonly difficulty separating red from green. Simulating it shows immediately whether your chart, button or status indicator still communicates — a red-and-green pass/fail badge often becomes two identical grey-brown blobs.
The fix is rarely to abandon colour. Add a second signal — a label, an icon, a pattern, or a difference in lightness — so the meaning survives without it.
Common questions
What is the most common type of colour blindness?
Red-green deficiency (deuteranopia and protanopia), which affects around 8% of men.
How do I make a chart accessible?
Do not rely on colour alone — add labels, patterns or clear differences in lightness.
Does this replace a real accessibility check?
It is a strong visual guide, but pair it with contrast checking for a full picture.
Which types of colour blindness does it simulate?
The common ones — red-green deficiencies like deuteranopia and protanopia, and blue-yellow tritanopia.
How do I fix a problem it reveals?
Add a second cue that does not depend on colour — a label, icon, pattern or shape — so the meaning survives for everyone.
Is my image uploaded?
No. The simulation runs in your browser and the image stays on your device.