Colorblindness simulator
See an image as people with color blindness perceive it (protan/deutan/tritan).
- Instant
- Free
- Private (processed locally)
- No sign-up
Design for every pair of eyes
A red-green chart can be unreadable for nearly one man in twelve. This tool simulates three types of color blindness and shows them next to the original, to spot accessibility issues at a glance.
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Load an image
Screenshot, chart, palette… or the built-in sample.
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Compare
Original, protan, deutan and tritan appear together.
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Fix
Add patterns, labels or contrast if needed.
The three simulated types
| Type | Affected color | Frequency |
|---|---|---|
| Protanopia | Red | Common (red-green) |
| Deuteranopia | Green | Most common |
| Tritanopia | Blue | Rare |
| — | Overall color blindness | ≈ 8% men, 0.5% women |
Processing happens pixel by pixel in your browser, with no upload. It is a useful design approximation, not a diagnosis.
Frequently asked questions
What is color blindness?
It is a difficulty telling certain colors apart, caused by atypical retinal cone function. It affects about 8% of men and 0.5% of women. The most common type concerns red and green perception.
What do protan, deutan and tritan mean?
Protan refers to reduced red perception, deutan to green, and tritan to blue. Protanopia and deuteranopia (red-green) are by far the most common; tritanopia (blue-yellow) is rare.
What is this simulator for?
To check that a chart, interface or palette stays readable for everyone. If two pieces of information differ only by a red/green color, they can become indistinguishable: better to add patterns, labels or contrast.
Is the simulation perfectly accurate?
No, it is an approximation based on color transformation matrices. It gives a faithful idea of the result, but real perception varies from person to person. It is a design guide, not a medical diagnosis.