Color Blind Simulator

How to use Color Blind Simulator

1. •Enter a color using the color picker, a hex code, or RGB values. You can also upload an image to simulate how an entire design appears under different types of color blindness.
2. •Browse the simulation results that show how your chosen color appears under each type of color vision deficiency: protanopia, deuteranopia, tritanopia, protanomaly, deuteranomaly, tritanomaly, achromatopsia, and achromatomaly.
3. •Compare the original and simulated colors side by side to identify where your design may lack sufficient contrast or relies too heavily on color alone.
4. •Iterate on your design by adjusting problematic colors until the simulated versions are distinguishable from one another.

What is color blindness?

Color blindness (color vision deficiency, or CVD) affects approximately 8% of men and 0.5% of women of Northern European descent, with varying prevalence across other populations. It is typically inherited and caused by absent or altered cone photoreceptor cells in the retina.

The three most common types are related to red-green perception. Protanopia is the absence of red cones, causing red to appear dark and indistinguishable from certain greens and browns. Deuteranopia is the absence of green cones, making green difficult to distinguish from red — this is the most common form. Tritanopia, the rarest form, involves the absence of blue cones and affects blue-yellow differentiation.

Each type also has an "-anomaly" variant (protanomaly, deuteranomaly, tritanomaly) where the cones are present but have an altered spectral sensitivity. These individuals have reduced color perception rather than total loss. Finally, achromatopsia is total color blindness — the person sees only in shades of gray.

Designing for color accessibility does not mean avoiding color. It means never relying on color alone to convey information. Use labels, patterns, icons, or sufficient brightness contrast in addition to color differences.

Common use cases

• •UI design review: Verify that status indicators (success/error/warning) are distinguishable without relying solely on green/red/yellow.
• •Data visualization: Ensure chart colors remain distinguishable under all common types of CVD. Avoid red-green as the only differentiator.
• •Brand guidelines: Check that brand color palettes maintain sufficient contrast and distinction for colorblind users.
• •Accessibility compliance: Meet WCAG 2.1 guideline 1.4.1 (Use of Color) by verifying that color is not the only visual means of conveying information.
• •Game design: Ensure game elements like team colors, health indicators, or item rarity colors are accessible to all players.

FAQ

Q: What percentage of users are affected? A: Roughly 1 in 12 men (8%) and 1 in 200 women (0.5%) have some form of color vision deficiency. Deuteranomaly (reduced green sensitivity) is the most common type.

Q: Is it enough to just avoid red and green together? A: Avoiding pure red/green combinations helps, but it is not sufficient. The best practice is to always provide a non-color indicator (text label, icon, pattern) alongside color.

Q: How accurate is the simulation? A: The simulator uses well-established color transformation matrices based on research by Brettel, Vienot, and Machado. The results are a close approximation of how affected individuals perceive colors.

Is my data safe?

Yes. This tool runs entirely in your browser. Your data is never sent to our servers.