Color Blindness Simulator
Preview any image or color the way people with protanopia, deuteranopia, tritanopia and five other types of color vision deficiency see it. Free and private — everything is simulated right in your browser.
or click to browse — JPG, PNG, WebP, GIF · stays on your device
| Vision type | Appears as | HEX |
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How to use the Color Blindness Simulator
- Upload an image or pick a color. Drag a JPG, PNG, WebP or GIF into the box above, or switch to Single color mode and enter any HEX code.
- Choose a vision type. Select protanopia, deuteranopia, tritanopia or one of five other deficiencies — the preview updates instantly. Press Compare all types to see every simulation side by side.
- Download or copy the result. Save any simulated image as a full-resolution PNG, or copy the simulated HEX codes for your accessibility notes and design reviews.
About this tool
Roughly 1 in 12 men and 1 in 200 women have some form of color vision deficiency, with red-green types (deuteranomaly, deuteranopia, protanomaly and protanopia) being by far the most common. This color blindness simulator lets designers, developers, teachers and data-visualization authors check whether charts, maps, status indicators, game interfaces and brand palettes still communicate clearly when red and green — or blue and yellow — become hard to tell apart.
The simulation uses the physiologically-based model published by Machado, Oliveira and Fernandes (2009): each pixel is converted to linear RGB, transformed with the matrix for the selected deficiency, and converted back to sRGB. All of this happens locally in your browser — your images are never uploaded to a server, so private photos and unreleased design mockups stay on your device. The tool is completely free, with no watermarks or sign-up.
Frequently asked questions
What do protanopia, deuteranopia and tritanopia mean?
They name which cone cells in the eye are affected. Protan types involve the L (red-sensing) cones and deutan types the M (green-sensing) cones — both cause red-green confusion. Tritan types affect the rare S (blue-sensing) cones and cause blue-yellow confusion. The “-opia” ending means the cone type is missing entirely (dichromacy), while “-anomaly” means it is present but shifted, giving a milder deficiency. Achromatopsia is the near-total absence of color perception.
How accurate is the simulation?
It is based on the widely cited Machado, Oliveira & Fernandes (2009) model, applied in linear RGB. Dichromatic types use full severity and the “-anomaly” types use a moderate 0.6 severity. Real color vision deficiency varies from person to person and screens differ, so treat the result as a faithful approximation rather than an exact reproduction of any individual’s vision.
Is my image uploaded to a server?
No. The image is read and processed entirely in your browser with the HTML5 canvas. Nothing is transmitted, stored or logged, so the tool is safe for confidential screenshots, medical imagery and unpublished artwork.
How can I make my designs color-blind friendly?
Never rely on hue alone: pair color with labels, icons, patterns or position, and keep strong lightness contrast between important elements. Avoid red/green combinations for critical states — blue/orange pairs are far safer. Run your palette or interface through this simulator and confirm that every state is still distinguishable in each vision type.