Color Blindness Simulator
Upload an image to see how it looks to someone with protanopia, deuteranopia, tritanopia, or another color vision deficiency — with a side-by-side before/after comparison you can download.
Drop an image here or choose a file
JPG, PNG, or WebP — up to 10 MB
Your image stays on your device. It is processed locally in your browser.
How to use the simulator
- Drag an image onto the upload area, or click it to choose a file from your device.
- Choose which color vision deficiency to simulate from the dropdown.
- Compare the original and simulated versions side by side.
- Download the simulated image to share with your team or include in a report.
What the output means
Each simulation applies a color transformation matrix that approximates how a given color vision deficiency changes perceived color. Protanopia, deuteranopia, and tritanopia are complete (dichromatic) forms affecting red, green, and blue perception respectively. Their "-anomaly" counterparts are weaker, partial versions. Achromatopsia removes color entirely, leaving only lightness.
Common use cases
Check whether a chart, map, or UI screenshot still communicates clearly to color-blind users, or preview a logo or infographic before publishing to catch color combinations that lose meaning under common color vision deficiencies.
Your image is never uploaded — simulation runs entirely on your device using your browser's built-in Canvas API.
Frequently asked questions
Which color vision deficiencies can this simulate?
Protanopia, deuteranopia, tritanopia (the three dichromatic forms), protanomaly, deuteranomaly, tritanomaly (the weaker anomalous-trichromacy forms), and achromatopsia (complete color blindness).
Is this simulation medically precise?
It uses well-established sRGB transformation matrices that are widely used for accessibility previews. It's a helpful approximation for design decisions, not a clinical diagnostic tool.
Is my image uploaded anywhere?
No. The image is decoded and simulated using the Canvas API directly in your browser. It is never sent to a server.
Can I download the simulated image?
Yes — click "Download simulated image" to save the current simulation as a PNG.