Color Blindness Simulator
See your image the way someone with color blindness would.
A free online color blindness simulator — upload an image and preview it under protanopia, deuteranopia, or tritanopia, side by side with the original. No signup, everything runs in your browser.
What does a color blindness simulator do?
A color blindness simulator transforms an image's colors to approximate how someone with a color vision deficiency would perceive it — the tool applies a standard RGB transformation for each type of color blindness. It's a quick way to check whether a design, chart, or graphic still communicates clearly when certain colors become hard to distinguish, without needing a colorblind volunteer on hand.
The three simulation types
Protanopia and deuteranopia both cause difficulty distinguishing red from green — together they make up the vast majority of color blindness cases, with deuteranopia (reduced green sensitivity) being more common than protanopia (reduced red sensitivity). Tritanopia, a blue-yellow deficiency, is far rarer but produces a very different confusion pattern — blues and yellows become hard to tell apart instead.
Why it matters for design
Roughly 1 in 12 men and 1 in 200 women have some degree of color vision deficiency. Any interface that relies purely on color to convey meaning — a red/green pass-fail indicator, a line chart with similarly-hued series, a map legend — risks being unreadable for that share of users. Pairing color with a second cue (an icon, a label, a pattern) is the standard fix once a simulation reveals the problem.
How the simulation works
Each pixel's red, green, and blue values are transformed through a fixed matrix specific to the chosen deficiency — this is the standard RGB approximation used across most web-based simulators, close enough for design review purposes though not a substitute for testing with actual colorblind users when accessibility is critical.
Frequently asked questions
How do I simulate color blindness on an image?
Upload or drag in an image, then pick a simulation type — protanopia, deuteranopia, or tritanopia. The original and simulated versions appear side by side, updating instantly.
What's the difference between protanopia, deuteranopia, and tritanopia?
Protanopia and deuteranopia both affect red-green discrimination and are the most common forms of color blindness — deuteranopia (reduced green sensitivity) is more common than protanopia (reduced red sensitivity). Tritanopia, a blue-yellow deficiency, is much rarer.
Why should I test my designs against color blindness?
Roughly 1 in 12 men and 1 in 200 women have some form of color vision deficiency. If a design relies only on color to convey meaning — a red/green status indicator, a chart with similarly-toned lines — simulating color blindness reveals whether that information is still readable to a meaningful share of users.
Is my image uploaded anywhere?
No. The simulation runs locally in your browser using a canvas — your image never leaves your device, and nothing is stored on a server.
Related tools: Color Contrast Checker · Color Name Finder · Grayscale Image
