How many people have colour blindness?

About one in twelve men and one in two hundred women has some form of colour vision deficiency, with the red-green types being by far the most common. Across an audience of a thousand, that means dozens of people do not see your colour pairings as intended.

Which type of colour blindness is most common?

The deutan forms, affecting green perception, are the most common, followed by the protan forms affecting red. Tritanopia, affecting blue and yellow, is far rarer and is not sex-linked the way the other two are.

How do I make a design colour-blind safe?

Never let colour be the only carrier of information — add a label, an icon, a shape or a pattern as a second signal. Beyond that, keep brightness contrast between elements high, because a difference in lightness still reads even when a difference in hue does not.

How accurate is this simulation?

It is an approximation using standard colour transformation matrices, and it is good for finding distinctions that disappear. Real colour vision varies in severity from person to person, so use the result to check a design rather than to conclude what any particular person sees.

Color

Color Blindness Simulator

Pick an image to see it as it appears to the three most common types of colour blindness.

Choose or drop an image PROCESSED ON YOUR DEVICE · NEVER UPLOADED

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Original Typical vision

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Deuteranopia Green — most common

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Protanopia Red

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Tritanopia Blue–yellow — rare

What this is

A colour blindness simulator shows an image roughly as it appears to eyes with a colour vision deficiency. Around one in twelve men and one in two hundred women has some form of it, so even a modest audience always includes people who do not see your design the way you do. The simulation applies the colour transformation matrices commonly used to approximate each type, and the result is an approximation — not an exact reproduction of anyone's experience.

How it works

Deuteranopia and protanopia both make red and green hard to separate, and both are far more common than tritanopia, which affects blue and yellow. That makes red-green pairings the riskiest: status indicators in red and green with no other marker are the accessibility failure found most often.

The fix is not to change the colours but to stop letting colour alone carry meaning. Add a shape, an icon, a label or a pattern as a second signal — the colour can then stay, because it is no longer the only thing carrying the information.

How to use it

Choose an image Upload a design, a chart, a thumbnail or a screenshot of an interface.
Compare the four panels The original and the three simulations appear side by side at the same size.
Look for information that vanishes Watch for distinctions that disappear — that is where colour is the only thing carrying meaning.

Common questions

How many people have colour blindness?: About one in twelve men and one in two hundred women has some form of colour vision deficiency, with the red-green types being by far the most common. Across an audience of a thousand, that means dozens of people do not see your colour pairings as intended.
Which type of colour blindness is most common?: The deutan forms, affecting green perception, are the most common, followed by the protan forms affecting red. Tritanopia, affecting blue and yellow, is far rarer and is not sex-linked the way the other two are.
How do I make a design colour-blind safe?: Never let colour be the only carrier of information — add a label, an icon, a shape or a pattern as a second signal. Beyond that, keep brightness contrast between elements high, because a difference in lightness still reads even when a difference in hue does not.
How accurate is this simulation?: It is an approximation using standard colour transformation matrices, and it is good for finding distinctions that disappear. Real colour vision varies in severity from person to person, so use the result to check a design rather than to conclude what any particular person sees.

Notes

The simulation approximates; it does not reproduce any individual's experience.
Images are processed in the browser and never uploaded.