Approximately 8% of men and 0.5% of women have some form of color vision deficiency. That is roughly 300 million people worldwide who experience your color palette differently from how you designed it. The Color Blindness Simulator lets you see your palette through their eyes — before you ship.
Color blindness simulation is a critical step in accessibility testing that is often skipped because it requires specialist software or knowledge. FreeColorPalettes makes it free and instant: paste your palette into the simulator, choose a vision deficiency type, and see exactly how your colors appear to a person with that condition.
The most common form — deuteranopia (red-green color blindness affecting green cone sensitivity) — affects 1 in 12 men. Under deuteranopia, red and green colors collapse into similar yellow-brown ranges, making many common color coding systems (traffic lights, error/success states, data charts) difficult or impossible to read.
What It Does
The Color Blindness Simulator applies scientifically modeled transformations to your palette colors to simulate how they appear under four common vision conditions: protanopia (missing red cones), deuteranopia (missing green cones), tritanopia (missing blue cones), and achromatopsia (complete color blindness/monochromacy). You can see both the original and simulated palette side by side for any combination.
Who It's For
Designers and developers building inclusive products, accessibility testers auditing existing UIs, data visualization engineers ensuring charts are distinguishable by colorblind users, and anyone whose design uses color to encode meaning in charts, maps, or status indicators.
How to Use This Tool
- 1Open the Color Blindness Simulator tool
- 2Paste or enter your palette's hex colors
- 3Select a simulation type (protanopia, deuteranopia, tritanopia, achromatopsia)
- 4Compare the simulated palette with your original
- 5Adjust colors that become indistinguishable under any condition
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Frequently Asked Questions
What types of color blindness should I test for?
Test for deuteranopia (red-green, green deficiency — most common at 5% of men) and protanopia (red-green, red deficiency — ~1% of men) as your minimum. These are by far the most prevalent forms. Tritanopia (blue-yellow) and achromatopsia (complete color blindness) are rarer but worth checking for critical accessibility requirements.
How do I make my color palette colorblind-friendly?
Avoid using red and green as the only distinguishing elements between states or data series. Supplement color with shape, pattern, label, or icon. Use a blue/orange polarity instead of red/green for critical binary distinctions. The Color Blindness Simulator shows you exactly which combinations fail under which conditions.
What percentage of users are color blind?
Approximately 8% of men and 0.5% of women worldwide have some form of color vision deficiency. For a product with 1 million male users, that is roughly 80,000 users who experience your color palette differently. This is too large an audience to ignore in any professional product.
Can I fix red-green color blindness issues without removing red and green?
Yes — the key is not to rely on red vs green as the only distinguishing signal. You can keep both colors if you add a secondary differentiator: a + symbol with green gains, a - symbol with red losses; a checkmark icon with success, an X with error; different saturation levels between states. Color + symbol = redundant coding = accessible.
Ready to try it?
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Open Color Blindness Palette Simulator