Upload an image or UI screenshot to simulate how people with Protanopia, Deuteranopia, Tritanopia, or Achromatopsia see your design.
Drag any panel to pan — all five stay in sync so you can compare the same detail across every deficiency.
Approximately 8% of men and 0.5% of women have color vision deficiency. Testing UI accessibility ensures interactive elements rely on icons and text rather than color alone.
The Severity slider linearly blends each panel between the original colors (0%) and the full-severity matrix (100%) — a simple, common way to preview "how much does this matter" that most on-screen simulators use, including browser devtools' own vision-deficiency emulation. It is not a physiologically validated model of anomalous trichromacy: real partial color blindness comes from a nonlinear shift in cone spectral sensitivity, not a blend toward normal vision. Treat intermediate values as an approximation for design intuition, not a diagnosis.
100% Private: Image manipulation uses HTML5 Canvas in local browser memory.
