Color Blindness Simulator & Checker
Upload an image and preview how it looks with protanopia, deuteranopia, tritanopia and other color vision deficiencies — entirely in your browser.
Input
JPG, PNG, WebP… processed entirely in your browser.
No green cones — the most common full color blindness.
Simulated preview
Upload an image to see how it looks with the selected type.
Guides
See your images the way someone with color vision deficiency (CVD) sees them. Upload a photo, pick a type — protanopia, deuteranopia, tritanopia, achromatopsia, or one of their milder "anomaly" variants — and get a live simulated preview side by side with the original, plus a download of the simulated image.
How it works
- Upload an image (JPG, PNG, WebP, and most other common formats).
- Pick a vision deficiency type from the dropdown.
- For the partial ("anomaly") types, drag the Severity slider to control how pronounced the effect is — the full types (protanopia, deuteranopia, tritanopia, achromatopsia) always simulate at 100%, since by definition there's no partial version of them.
- Compare the original and simulated images side by side, then download the simulated PNG.
Everything runs as a canvas pixel transformation in your browser — your image is never uploaded to a server, and nothing is stored.
The types, explained
- Protanopia — no red cones; reds appear dark and muted.
- Deuteranopia — no green cones; the most common full color blindness.
- Tritanopia — no blue cones; blues and yellows are hard to distinguish.
- Achromatopsia — no color vision at all; the world appears in grayscale.
- Protanomaly / Deuteranomaly / Tritanomaly / Achromatomaly — the milder, partial ("anomalous") forms of the above. Deuteranomaly is the most common color vision deficiency overall.
Why does this matter for design and accessibility?
An estimated 1 in 12 men and 1 in 200 women have some form of color vision deficiency. If a design, chart, or infographic relies on color alone to convey information — a red/green "pass/fail" status, or a map legend — a meaningful share of your audience may not be able to tell the difference. Simulating how your image looks under each type is a quick way to check whether it still reads clearly.
Is this simulation exact?
It's a widely-used approximation, based on published color-vision-deficiency research (the transformation matrices are the same family used by many browser-based CVD simulators). It's accurate enough to reveal real accessibility problems — colors that collapse into each other, low-contrast text on a colored background — but it isn't a substitute for testing with people who actually have the condition, since severity and presentation vary from person to person.
Does this tool store my image?
No. The upload, the simulation, and the download all happen locally in your browser using the Canvas API — your image is never sent to our servers.