Colour Blindness Simulator
See how an image looks with protanopia, deuteranopia, tritanopia or achromatopsia, side by side. Check designs for accessibility without uploading them.
No uploads
How to use Colour Blindness Simulator
- 1Open Colour Blindness Simulator. It runs in your browser, no sign-up.
- 2Drop your file here or choose it. It stays on your device; nothing is uploaded.
- 3Adjust the options until the preview looks right.
- 4Download the result.
Questions
How accurate is the simulation?
It uses the Machado, Oliveira & Fernandes (2009) model at full severity, applied in linear RGB. Real perception varies person to person, and many people have milder anomalous trichromacy rather than full dichromacy.
What should I look for?
Information carried only by colour — red/green status dots, chart series, error states. If two things become indistinguishable, add labels, patterns or contrast.
Is my image uploaded?
No. Every pixel is transformed in your browser with the Canvas API.
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