Color Blindness Simulator
See how colors appear to people with different types of color vision deficiency. Enter a color or build a palette to check accessibility.
Simulate a Single Color
Enter a color via hex, RGB, or the color picker to see all simulations side by side.
Palette Accessibility Checker
Add multiple colors to see if they remain distinguishable under each type of color blindness.
Types of Color Blindness
Protanopia
~1% of males
Complete absence of red cone cells. Reds appear dark and brownish. Difficulty distinguishing red from green, and red from black in dark shades.
Deuteranopia
~1% of males
Complete absence of green cone cells. Greens shift toward beige/tan. Similar to protanopia but reds don't appear as dark. Most common dichromacy.
Tritanopia
~0.003% of population
Complete absence of blue cone cells. Blues appear greenish, yellows appear pink/violet. Very rare, affects males and females equally.
Achromatopsia
~1 in 30,000
Complete color blindness — only shades of gray are perceived. Caused by non-functioning or absent cone cells. Often accompanied by light sensitivity.
Protanomaly
~1% of males
Reduced sensitivity in red cones. Reds, oranges, and yellows appear shifted toward green. Less severe than protanopia — some red-green distinction remains.
Deuteranomaly
~5% of males
Reduced sensitivity in green cones. The most common form of color blindness. Greens look more red/yellow. Mild cases may go unnoticed for years.
What is a Color Blindness Simulator?
A color blindness simulator is an accessibility tool that transforms colors using mathematical models of color vision deficiency. It helps designers, developers, and content creators understand how their color choices appear to people with different types of color blindness. By testing your palette before shipping, you ensure that color-coded information — status indicators, charts, navigation elements — communicates effectively to all users.
Understanding Color Vision Deficiency
Human color vision relies on three types of cone cells in the retina, each sensitive to different wavelengths: long (red), medium (green), and short (blue). Color blindness occurs when one or more cone types are absent (dichromacy) or have shifted sensitivity (anomalous trichromacy):
- Protan defects (red): Protanopia (no red cones) and protanomaly (reduced red sensitivity). Affects ~2% of males. Reds appear darker and can be confused with greens and browns.
- Deutan defects (green): Deuteranopia (no green cones) and deuteranomaly (reduced green sensitivity). Affects ~6% of males. The most common category. Greens shift toward reds and browns.
- Tritan defects (blue): Tritanopia (no blue cones) and tritanomaly (reduced blue sensitivity). Very rare (~0.003%). Blues and yellows become hard to distinguish.
- Achromatopsia: Total color blindness. Only luminance (brightness) is perceived. Extremely rare (~1 in 30,000).
How the Simulation Works
This tool converts your input color from sRGB to linear RGB, applies a color transformation matrix specific to each deficiency type, then converts back to sRGB for display. The matrices are based on research by Brettel, Viénot, and Machado, widely used in accessibility tools. Anomalous trichromacy (protanomaly, deuteranomaly) uses interpolated matrices that blend between normal vision and full dichromacy to model the partial sensitivity loss.
Design Tips for Color Accessibility
Never rely on color alone to convey meaning. Pair color with text labels, icons, patterns, or varying brightness. Use the palette checker to verify that all colors in your UI remain distinguishable under each type. Pay special attention to red/green combinations in status indicators, charts, and form validation. Aim for sufficient luminance contrast between any adjacent colors.
Frequently Asked Questions
What is color blindness?
Color blindness (color vision deficiency) is a condition where certain cone cells in the retina don't function normally, making it difficult to distinguish between specific colors. About 8% of men and 0.5% of women worldwide have some form of color blindness.
What are the different types of color blindness?
The main types are: protanopia (no red cones), deuteranopia (no green cones), tritanopia (no blue cones), achromatopsia (total color blindness), protanomaly (reduced red sensitivity), and deuteranomaly (reduced green sensitivity — the most common form, affecting ~5% of males).
How does this simulator work?
The simulator applies color transformation matrices in linear RGB space to approximate how each type of color vision deficiency changes color perception. Each matrix models the specific cone deficiency or sensitivity reduction for that condition.
Why should I test my designs for color blindness?
With roughly 300 million people affected worldwide, failing to consider color blindness means a significant portion of your audience may miss important information conveyed through color alone, such as status indicators, chart data, or form validation states.
How can I make my designs more accessible?
Use the palette checker to verify your colors are distinguishable under all vision types. Add patterns, labels, icons, or varying brightness alongside color. Avoid relying on red vs. green alone for status indicators. Ensure sufficient luminance contrast between adjacent elements.
Related Tools
- Color Palette Generator — Generate beautiful color schemes with harmony modes and contrast checking.