Color Blindness Simulator
betaThis free colour blindness simulator shows how your image or design appears to people with colour-vision deficiencies. Drop an image and compare the original with protanopia, deuteranopia, tritanopia (and their milder anomalous forms) plus full achromatopsia, side by side. Use it to check that charts, maps and UI stay readable for everyone. Everything runs in your browser.
See how your design looks to someone with colour blindness. Drop an image and switch between types of colour-vision deficiency, side by side with the original. Everything runs in your browser.
How to use Color Blindness Simulator
- 1 Drop or paste an image (a chart, design or screenshot).
- 2 Pick a colour-vision deficiency to simulate.
- 3 Compare the original and simulated views side by side.
- 4 Download the simulated image if you need it.
Frequently asked questions
Which types can I simulate?
Protanopia, deuteranopia and tritanopia (the three dichromacies), their milder anomalous versions, and achromatopsia (no colour at all).
Is my image uploaded?
No. The simulation runs on a canvas in your browser, so your image never leaves your device.
How accurate is it?
It uses the widely used dichromacy approximation matrices. They are a strong guide for design review, not a medical diagnostic.
Why does this matter for accessibility?
About 1 in 12 men has some colour-vision deficiency. Simulating it helps ensure charts, maps and status colours are distinguishable without relying on colour alone.
Does it work offline?
Yes. GoodWebTools is a PWA, so once loaded the simulator works with no internet connection.