Upload an image or pick a color and preview how it looks to people with different types of color vision deficiency.
🔒 100% private — your image never leaves your device
Drag & drop an image
or click to browse — you can also paste (Ctrl/Cmd + V)
JPGPNGWEBPGIF
Enter a hex value (e.g. #e11d48) or use the swatch.
How it works
Everything runs on your device — no upload, no wait.
1
Add your source
Drop in an image, paste a screenshot, or pick a single color to test.
2
See every CVD type
Each preview is redrawn on a canvas using the standard color-vision transform matrices.
3
Save or copy
Download the simulated images, or copy the transformed hex values for a single color.
About the color-vision types
Protanopia and deuteranopia are the two most common forms
of red-green color blindness — protanopia is a missing L (long / red) cone, deuteranopia a
missing M (medium / green) cone. Together they affect roughly 8% of men.
Tritanopia is a rare blue-yellow deficiency (missing S / short cone), and
achromatopsia is total color blindness, where the world is seen in shades
of grey.
Each preview is produced by converting pixels to the cone-response space and applying the
widely used Brettel / Machado-style linear transform matrices, then drawing the result back
onto a <canvas>. It's a close approximation — useful for checking whether
your design, chart or UI stays readable — not a medical diagnosis.
🔒
Private by design. Your image is decoded and simulated entirely in your browser. Nothing is uploaded — we never see it.
Frequently Asked Questions
What types of color blindness can I preview?▼
You can simulate the four main types: protanopia (red-blind), deuteranopia (green-blind), tritanopia (blue-blind) and achromatopsia (total color blindness). Show them all at once or focus on a single type.
How accurate is the simulation?▼
It uses the widely accepted color-vision transforms that most accessibility tools rely on, so it's a close, practical approximation. It's great for checking whether a design, chart or interface stays readable, but it is not a medical diagnosis.
Can I test a single color instead of an image?▼
Yes. Switch to Single color mode, pick a color or type a hex value, and you'll see how that exact shade shifts for each type of color vision deficiency, with copyable hex values.
What image formats can I upload?▼
JPG, PNG, WEBP and GIF all work. You can drag and drop a file, click to browse, or paste a screenshot directly with Ctrl/Cmd + V.
Can I save the simulated results?▼
Yes. In image mode you can download each simulated preview as a PNG, and in single-color mode you can download or copy the transformed color values.
Is my image uploaded anywhere?▼
No. Your image is decoded and simulated entirely in your browser. Nothing is uploaded and we never see it — everything stays on your device.