Colour-blindness simulator — see a colour three ways
Enter a colour and see how it appears under protanopia, deuteranopia and tritanopia. It simulates entirely in your browser (0 uploads, works offline).
How to use it
- Enter a colour.
- Compare the original with the three simulated versions.
- Adjust your palette if two colours collapse together.
FAQ
How do I check a colour for colour blindness for free?
Enter the colour and this page applies the standard simulation matrices for the three common types of colour blindness, showing swatches side by side — on your device with no upload.
Why does this matter for design?
Roughly one in twelve men has some colour-vision deficiency. If two of your UI colours look identical under simulation, users may not be able to tell states apart, so pair colour with another cue.
Is my colour uploaded anywhere?
No. Simulation runs entirely in your browser and nothing is transmitted or stored, which you can verify by turning off your Wi-Fi.
Which types are covered?
Protanopia (red-weak), deuteranopia (green-weak) and tritanopia (blue-weak) — the three dichromacies that cover most cases.
Limits
Simulates single colours with standard matrices; it is an approximation, not a medical or per-image tool.
Related
The contrast checker verifies legibility; the Tailwind shade generator builds scales.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.