Simulate your colors
| Original | Protanomaly (red-weak) | Deuteranomaly (green-weak) | Tritanomaly (blue-weak) | Remove |
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Export the simulated palette
Live text preview
This is body text rendered with your chosen foreground and background colors, simulated for the selected vision type. If the text becomes hard to read here, it will be hard to read for roughly one in twelve male visitors.
Simulation uses color-vision-deficiency transforms applied in linear RGB space using the physiologically-based severity matrices of Machado, Oliveira & Fernandes (2009), with interpolation between severity levels. For hard WCAG numbers on a specific pair, use our contrast checker; for a full accessible palette, try the palette generator. To check an entire live page, run the free Accessibility Scanner.
What the three types mean
- Protanomaly — reds look darker and can vanish against green or grey.
- Deuteranomaly — the most common form; red and green become nearly indistinguishable.
- Tritanomaly — very rare; blue and yellow merge together.
Practical rule: never rely on hue alone to convey meaning. Pair color with icons, labels or patterns — that is also what WCAG SC 1.4.1 requires.
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Frequently asked questions
How accurate is the simulation?
The tool uses the standard Machado et al. (2009) severity model for protanopia, deuteranopia and tritanopia — the same matrices used in professional design tools. It approximates how colors are perceived, but only a clinical test can diagnose color vision deficiency in a person.
Are my colors uploaded anywhere?
No. The simulation runs entirely in JavaScript in your browser. Your palette never leaves your device.
Which type should I check against?
Deuteranomaly (red-green) is by far the most common, so start there. If your design works for deuteranopia and tritanopia, it will almost always work for rarer types too. Check both text contrast and chart/status colors.
Does this replace a WCAG contrast check?
No — they answer different questions. A contrast checker tells you whether text is readable; this simulator shows whether two hues remain distinguishable when color vision is impaired. Use both: contrast for legibility, simulation for color coding.