Simulate different types of color blindness and test your designs for accessibility. See how colors appear to people with protanopia, deuteranopia, tritanopia, and achromatopsia.
Original Color
How it appears with Protanopia (Red-Blind)
Protanopia: Red-blind. Affects ability to distinguish red and green colors (~1% of males).
Deuteranopia: Green-blind. Most common form, affects red-green distinction (~1% of males).
Tritanopia: Blue-blind. Affects blue-yellow distinction (rare, ~0.001% of people).
Achromatopsia: Total color blindness. Only grayscale vision (very rare, ~0.003%).
A color blindness simulator is a tool that transforms colors to show how they appear to people with different types of color vision deficiencies (CVD). Color blindness affects approximately 1 in 12 men (8%) and 1 in 200 women (0.5%) worldwide—about 350 million people. This means a significant portion of your audience may perceive colors differently than you intend, making color accessibility crucial for inclusive design.
Our free Color Blindness Simulator uses scientifically-based color transformation algorithms to accurately simulate how colors are perceived by people with protanopia, deuteranopia, tritanopia, and achromatopsia. Simply select a color and choose a simulation type to see instant results. This helps designers and developers create accessible interfaces that work for everyone, regardless of their color vision capabilities.
Color blindness testing is essential because color plays a critical role in user interface design, data visualization, and information communication. If important information is conveyed solely through color, users with CVD may miss it entirely. For example, red error messages may be indistinguishable from black text for someone with protanopia. Green "success" states may blend with red "error" states for someone with deuteranopia.
Testing for color blindness accessibility improves user experience for everyone, not just those with CVD. It ensures your designs are robust, clear, and functional regardless of how colors are perceived. It also helps meet WCAG (Web Content Accessibility Guidelines) standards, which require that color is not the sole means of conveying information. By testing early and often, you prevent costly redesigns and ensure your product is truly inclusive from the start.
Protanopia is a type of red-green color blindness caused by the absence of red photoreceptors (L-cones) in the eye. People with protanopia cannot perceive red light and have difficulty distinguishing between red, orange, yellow, and green. Red appears as dark gray or black, while green appears beige or gray. This affects about 1% of males and is the second most common form of color blindness.
Design implications: Red/green color coding (common in error/success messages) is problematic. Red text on black backgrounds may be nearly invisible. Traffic lights can be challenging to distinguish.
Deuteranopia is the most common form of color blindness, affecting about 1% of males. It's caused by the absence of green photoreceptors (M-cones). People with deuteranopia have similar red-green confusion as protanopia but perceive colors slightly differently. Reds appear brownish-yellow, and greens appear beige. The distinction between red, orange, yellow, and green is difficult or impossible.
Design implications: Like protanopia, red/green distinctions fail. However, deuteranopia tends to have slightly better perception of darker reds compared to protanopia.
Tritanopia is a rare form of color blindness affecting approximately 0.001% of people (1 in 10,000). It's caused by the absence of blue photoreceptors (S-cones). People with tritanopia have difficulty distinguishing between blue and green, and between yellow and violet. Blue appears as green, purple appears as red, and yellow and orange appear as pink or light red.
Design implications: Blue/yellow color schemes are problematic. Blue hyperlinks may be difficult to distinguish from text. However, red/green distinction remains intact, unlike protanopia and deuteranopia.
Achromatopsia is extremely rare (~0.003% of people) and involves complete absence of color perception. People with achromatopsia see only in shades of gray, like a black-and-white photograph. This is caused by the absence or malfunction of all three types of cone cells. Achromatopsia often comes with other vision problems like extreme light sensitivity and poor visual acuity.
Design implications: Any color-based distinctions completely fail. Contrast and brightness become the only visual differentiators. Clear labeling, icons, and patterns are essential.
Our simulator uses LMS (Long, Medium, Short wavelength) color space transformation. Here's the process:
Each type of color blindness has a specific transformation matrix derived from scientific research on cone cell responses. These matrices accurately model how the absence or malfunction of specific cone types affects color perception.
Some color combinations work better for color-blind users:
The Web Content Accessibility Guidelines (WCAG) provide specific requirements:
Using our simulator helps identify potential violations of these criteria, but should be combined with contrast checking tools for complete accessibility testing.
Our color blindness simulator:
Note: Simulators provide approximations based on research. Individual experiences vary, and the best accessibility testing includes feedback from actual users with CVD.
No simulator is perfect. Our tool uses research-based algorithms that provide good approximations, but individual experiences vary. Color blindness exists on a spectrum, and our simulator shows the most common manifestations. For critical applications, test with actual users who have CVD.
Deuteranopia (green-blind) is the most common, affecting about 1% of males. Combined with protanopia (red-blind), red-green color blindness affects about 8% of males and 0.5% of females of Northern European ancestry.
Yes, red-green color blindness (protanopia and deuteranopia) is X-linked, making it much more common in males. However, tritanopia and achromatopsia affect males and females equally.
Use our simulator to test colors, ensure you don't rely solely on color to convey information, add text labels or icons, use patterns or textures, maintain sufficient contrast, and test with color-blind users when possible.
Not necessarily, but don't use them as the sole differentiator. Red and green can be used if they're also distinguished by text, icons, position, or other non-color cues. For example, a red error icon with an X is fine, as the X symbol provides the primary distinction.