Color Blindness Simulator
Test how your designs appear to users with different types of color vision deficiency.
About 1 in 12 men has some form of color vision deficiency. Deuteranopia (red-green) affects ~6% of men globally. Always test your UI palette against multiple deficiency types and combine with the WCAG Contrast Checker for full accessibility compliance.
Color Blindness Simulator — Design for Every Type of Vision
With approximately 300 million people worldwide experiencing some form of color vision deficiency, testing your designs through a color blindness simulator is an essential step in any accessibility-conscious workflow. Colaro's free color blindness simulator lets you upload an image or screenshot and immediately see how it appears to users with deuteranopia, protanopia, tritanopia, and achromatopsia — revealing whether your color choices communicate clearly for everyone.
Types of Color Blindness Explained
Color blindness isn't a single condition — it encompasses several distinct types of color vision deficiency, each affecting perception differently. Deuteranopia (green-weak) and protanopia (red-weak) are the most common, together affecting about 6% of males. Both cause difficulty distinguishing red and green hues, which can make traffic lights, status indicators, and charts using only red-green color coding ambiguous or invisible. Tritanopia (blue-weak) is much rarer, affecting fewer than 0.01% of people, and causes confusion between blue and yellow tones. Achromatopsia, the most severe form, results in complete color blindness — the world appears in grayscale, making sufficient luminance contrast absolutely critical.
Designing for Deuteranopia and Protanopia
The most impactful design change for red-green color blind users is to stop using red and green as the sole differentiators for important information. Add a textual label, icon, or pattern alongside the color — for example, a checkmark icon for success states rather than just green, or an X icon for errors rather than just red. In data visualization, use shape, line style, or direct labeling alongside color encoding. Blue-orange and purple-yellow color palettes are much more accessible for deuteranopic and protanopic users than traditional red-green schemes.
WCAG Guidelines for Color Blindness Accessibility
WCAG 2.1 Success Criterion 1.4.1 states that color must not be used as the only visual means of conveying information. This directly addresses color blindness — if a form field turns red to indicate an error, it must also include an error icon or text message. Criterion 1.4.3 (contrast) and 1.4.11 (non-text contrast) ensure sufficient luminance contrast that helps color-blind users distinguish elements regardless of hue perception. Use this simulator alongside Colaro's contrast checker to cover both criteria in one workflow.
Frequently Asked Questions
How many people are color blind?
Approximately 300 million people worldwide have some form of color vision deficiency, including about 8% of males of Northern European descent.
What is the most common type of color blindness?
Deuteranomaly (partial green deficiency) is the most common, affecting about 5% of males. Combined red-green color deficiencies affect roughly 8% of males.
Can color blind people see all colors?
Most people with color blindness can see colors, but have difficulty distinguishing specific hue pairs (typically red-green or, more rarely, blue-yellow). Complete color blindness (achromatopsia) is rare.
Does this simulator work for web app screenshots?
Yes. You can upload screenshots of any digital interface to see how it appears to users with different types of color vision deficiency.