Color Blindness Simulator
See any image or screenshot as people with protanopia, deuteranopia, tritanopia or achromatopsia do. Free, in your browser, no upload.
- No uploads
- No limits
- No signup
Drop an image to see it through colour-blind eyes
JPG, PNG, WebP or HEIC, or paste a screenshot with Ctrl+V (⌘V on Mac).
- Input:
- Image
- Output:
- Colour-blind views · PNG
- Runs on:
- Your device
- Size limit:
- None
- Account:
- Not needed
How to use Color Blindness Simulator
Add your image
Drop a screenshot, chart, map or photo, or paste one straight from the clipboard. It opens in your browser and is never uploaded.
Compare the simulations
See all seven types of colour blindness at once, or put one next to the original. Move the severity slider to see milder or stronger anomalous vision.
Download what you need
Save any simulation as a full-resolution PNG to share with your team or add to an accessibility report.
Why Color Blindness Simulator on Toolshed
No uploads
Everything runs in this browser tab. Your files never leave your device.
No limits
No file-size caps, no daily quotas. Process as much as your device can handle.
No signup
No account, no email, no watermark.
Frequently asked questions
How accurate are the simulations?
They use the models researchers use: Viénot et al. (1999) for protanopia and deuteranopia, Brettel et al. (1997) for tritanopia and Machado et al. (2009) for the anomalous types, all computed in linear RGB. They show what a typical person with each type sees on a standard sRGB screen; individual vision varies.
What is the difference between -opia and -anomaly?
In protanopia, deuteranopia and tritanopia one type of cone is missing. In protanomaly, deuteranomaly and tritanomaly it works, but shifted, so colours are only partly confused. The severity slider sets how strong that shift is; 100% is close to the matching -opia.
Is my image uploaded?
No. The simulations run in your browser, in a background thread so even large photos don't freeze the page. Nothing is sent to a server.
Are my files uploaded anywhere?
No. Color Blindness Simulator runs entirely in your browser. Your files are processed on your device and are never sent to a server.
Is there a file size limit?
No fixed limit. The only limit is your device's memory. Very large files work best in a desktop browser.
Is Color Blindness Simulator really free?
Yes. There's no account and no watermark. A short optional ad, or a 20-second wait, unlocks each download. That's how we keep it free.