Color Blindness Simulator

Runs on your device. Nothing is sent.Your image never leaves your device - it's processed in the browser.

Drop an image here or click to choose

A photo, screenshot, chart or design - JPG, PNG, WebP, GIF

See any photo, chart or design the way people with color blindness do - protanopia, deuteranopia, tritanopia and more, side by side. No upload.

Check whether your design, chart, map or photo still works for the one in twelve men and one in two hundred women with color vision deficiency. Drop in an image and see it as people with deuteranopia, protanopia, tritanopia and achromatopsia see it, all at once or one at a time with a before-and-after slider. Lower the severity to see the milder anomalous forms, which are the most common, and download any view as a PNG. The simulation follows the Machado (2009) model used by browser developer tools, and your image never leaves your device.

Frequently asked questions

How accurate is the simulation?

It uses the physiologically based model by Machado, Oliveira and Fernandes (2009), the same one Chrome and Firefox developer tools use, applied in linear RGB. No simulation can show exactly what one person sees - color vision varies - but it reliably shows which colors become hard to tell apart.

What's the difference between -opia and -anomaly?

In deuteranopia, protanopia and tritanopia one of the three cone types is missing. In deuteranomaly, protanomaly and tritanomaly it is present but shifted, so colors are weaker rather than gone. The anomalous forms are far more common: deuteranomaly alone affects about 5% of men.

How do I make a design color-blind friendly?

Don't rely on color alone: add labels, patterns, icons or line styles. Avoid red/green and green/brown pairs for meaning, give important colors a clear difference in lightness, and prefer palettes such as blue/orange. Then check the result here in every type.

Is my image uploaded?

No. The image is opened and processed in your browser with the canvas API; nothing is sent to a server, and the page keeps working offline once loaded.

Color Blindness Simulator

Frequently asked questions

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