Color Blindness Simulator
Preview how an image looks to people with protanopia, deuteranopia, or tritanopia.
How to Use
- Drop a design or photo.
- Toggle between the three simulation modes.
- Compare side-by-side with the original.
| Deuteranopia — green-blind | ~6% of men |
| Protanopia — red-blind | ~1% of men |
| Tritanopia — blue-yellow | ~0.01% |
| Achromatopsia — no color | very rare |
| Any type (men / women) | ~8% / ~0.5% |
Types
About the Color Blindness Simulator
Need a hand with colour and design work? The Color Blindness Simulator does the work for you — free, and right here in your browser. Preview how an image looks to people with protanopia, deuteranopia, or tritanopia.
How it works
Type in what you have, and the answer shows up right away. Change anything and it updates by itself. Everything runs in your browser, so it is fast and nothing you type is sent away.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
Are these simulations accurate?
They use the Brettel/Viénot matrix model — a well-established approximation of dichromacy (the complete absence of one cone type). It is close enough to reliably catch red-green failures in a UI, charts, or a design, though real-world anomalous trichromacy (partial deficiency) varies person to person and is milder than full dichromacy.
How common is color blindness?
About 1 in 12 men (~8%) and 1 in 200 women (~0.5%) have some form. The overwhelming majority is red-green (protanopia or deuteranopia); blue-yellow (tritanopia) is very rare, and total color blindness (achromatopsia) is rarer still. On a typical site that means several percent of your audience.
What does this tell me to fix?
If two states only differ by color — a red vs green status dot, a chart with red and green lines, a "required" field marked only in red — they can become indistinguishable. The fix is to add a second cue: a label, icon, pattern, or a brightness/shape difference, so the meaning never depends on hue alone.
Is my image uploaded?
No. The image is decoded to a canvas and transformed pixel-by-pixel in your browser. Nothing is sent to a server.
How do I use the Color Blindness Simulator?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Is it free? Does it work without internet?
Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.
Where does my data go?
Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.
Common Use Cases
UI & chart accessibility
Verify status indicators, charts, and maps stay readable without relying on hue alone.
Brand & marketing review
Check that a logo or palette still works for color-blind viewers before launch.
Education & empathy
See first-hand how a design looks to ~8% of men — a quick reality check for any team.
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