Color Blindness Simulator

Simulate how colors appear to colorblind users free online. Real transformation matrices for protanopia, deuteranopia, and tritanopia -- not a guess, genuine color science.

or test a single color

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How to Use This Tool

Upload an image or pick a colorTest a design, chart, or single swatch

See all three deficiency types at onceProtanopia, deuteranopia, tritanopia side by side

Identify problem areasCatch color-only information that becomes ambiguous

Real Color Science, Not a Visual Approximation

Simulating color vision deficiency accurately requires transforming colors through LMS cone-response space using established research-derived matrices, not simply desaturating or shifting hues arbitrarily. This tool applies those genuine transformation matrices for each of the three main deficiency types, producing scientifically grounded simulation rather than a rough visual approximation.

Why Testing All Three Types Matters

Protanopia, deuteranopia, and tritanopia affect color perception in genuinely different ways, since each corresponds to a different missing cone type. A design that holds up under one simulation might still fail under another, which is why testing all three side by side catches problems a single check would miss.

The Real Design Risk This Catches

Charts, status indicators, and form validation that rely purely on red-versus-green coloring to convey meaning can become genuinely ambiguous or unreadable for users with red-green color vision deficiency, which affects a meaningful share of the population. Seeing your actual design under simulation makes this risk concrete rather than abstract.

Frequently Asked Questions

Established color transformation matrices based on research into how each type of color vision deficiency affects color perception in LMS (long, medium, short wavelength cone) color space -- a scientifically grounded simulation method, not an arbitrary visual filter.

Protanopia is the absence of red-sensing cones, deuteranopia is the absence of green-sensing cones, and tritanopia is the absence of blue-sensing cones -- each affects color perception differently, which is why this tool simulates all three separately rather than applying one generic 'colorblind' filter.

Color vision deficiency affects a meaningful percentage of the population (especially red-green types, which affect roughly 8% of men). Designs relying solely on color to convey information -- like red versus green status indicators -- can become genuinely unusable for these users, which is exactly the kind of problem this simulator helps catch before publishing.

Yes, uploading an image applies the same transformation matrix to every pixel, letting you see how an entire design, chart, or photo would appear under each type of color vision deficiency, not just an isolated color swatch.

This simulates how colors shift under specific color vision deficiencies, which is genuinely useful for catching problems, but full color accessibility also involves not relying on color alone to convey critical information (adding patterns, labels, or icons alongside color), which this tool doesn't directly enforce.