Upload any image and instantly see how it appears to people with deuteranopia, protanopia, tritanopia, and achromatopsia. Free color blindness checker — runs entirely in your browser.
Drag and drop or click to upload any JPG, PNG, or WebP image. Everything stays in your browser — nothing is uploaded to a server.
See your image through four types of color blindness: deuteranopia (green-blind), protanopia (red-blind), tritanopia (blue-blind), and achromatopsia (total color blindness).
Identify problem areas where important information is lost. Adjust your color palette so your designs, games, and content work for everyone.
Approximately 8% of men and 0.5% of women have some form of color vision deficiency. Here are the four types this tool simulates:
The most common type, affecting about 6% of males. People with deuteranopia cannot distinguish between red and green hues. Reds, greens, and browns may all appear as shades of yellow or tan.
Affects about 1% of males. People with protanopia have no red cone cells. Red appears as dark brownish-green, and orange and green are nearly indistinguishable. Reds also appear much darker than normal.
Rare, affecting fewer than 1 in 10,000 people. People with tritanopia cannot distinguish blue from green, or yellow from violet. Blues appear greenish, and yellows appear pink or light grey.
Extremely rare, affecting roughly 1 in 30,000 people. People with achromatopsia see the world entirely in shades of grey. They rely solely on brightness differences to distinguish objects.
Over 300 million people worldwide have some form of color vision deficiency. If your design relies on color alone to convey information — red for errors, green for success, color-coded charts — a significant portion of your audience may miss critical details.
For game developers, inaccessible color choices mean players cannot distinguish between teams, power-ups, or hazards. For web designers, poor color contrast makes navigation impossible. For content creators, infographics and thumbnails lose their meaning.
Testing your designs with a color blindness checker before publishing is the fastest way to catch these issues. Use shape, pattern, texture, and labels alongside color — never rely on color as the sole differentiator.
Color blindness (color vision deficiency) is a condition where a person cannot distinguish certain colors or perceives them differently than most people. It affects approximately 1 in 12 men (8%) and 1 in 200 women (0.5%) globally — that is roughly 350 million people worldwide. The condition is usually inherited and caused by absent or altered photoreceptor cells (cones) in the retina. The most common forms involve difficulty distinguishing red from green.
These are the three main types of dichromacy (two-cone vision). Deuteranopia (green-blind) is by far the most common, affecting ~6% of males — the green-sensitive cones are missing, making red and green look similar. Protanopia (red-blind) affects ~1% of males — the red-sensitive cones are missing, causing reds to appear very dark and hard to distinguish from greens. Tritanopia (blue-blind) is extremely rare — the blue-sensitive cones are missing, making it hard to tell blue from green and yellow from violet. Each type merges a different pair of colors, which is why testing with all three simulations matters.
The golden rule is: never use color as the only way to convey information. Supplement color with text labels, icons, patterns, or shapes. For charts, add direct labels or use distinct line patterns (dashed, dotted). For UI elements, pair red/green status indicators with icons (checkmarks, X marks). Maintain high contrast ratios (WCAG recommends at least 4.5:1 for text). Avoid problematic color pairs: red/green, green/brown, blue/purple, and green/grey. Tools like this color blindness checker help you verify your palette before publishing.
The most problematic combinations are red + green (indistinguishable for deuteranopia and protanopia), green + brown, blue + purple (problematic for tritanopia), green + grey, and red + brown. Safe color palettes often rely on blue + orange (distinguishable by nearly all types of color blindness), high-contrast black + white, or blue + red. When in doubt, upload your design to this checker and verify all four simulation types. If critical information disappears in any simulation, adjust your palette.
This tool uses the Canvas API in your browser to apply scientifically-derived color vision deficiency (CVD) matrices to every pixel in your image. Each matrix simulates how a specific cone deficiency alters color perception by transforming the RGB values. For example, the deuteranopia matrix remaps green-channel information to approximate what a person without green cones would see. All processing happens client-side — your image never leaves your device. The tool supports JPG, PNG, and WebP files.
This tool is a simulator, not a diagnostic test. It shows people with normal color vision what an image looks like through color-blind eyes. If you want to test your own color vision, look for an Ishihara plate test or an anomaloscope test administered by an eye care professional. That said, comparing the original image with the simulations can be informative — if you cannot see differences between the original and a particular simulation, it may indicate you have that type of color vision deficiency, and you should consult an optometrist for a formal diagnosis.
Your image is completely private. This color blindness checker runs entirely in your browser using the HTML5 Canvas API. No data is sent to any server. The image is loaded into memory, processed locally, and discarded when you close the page. This makes the tool safe for checking confidential designs, unreleased game assets, or any other sensitive visual content.
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