Color Blindness Simulator
See any image as people with protanopia, deuteranopia or tritanopia see it · free, no signup
Color Blindness Simulator — Check Your Design for Colour-Vision Accessibility
About 1 in 12 men and 1 in 200 women have some form of colour-vision deficiency, most often trouble telling reds from greens. If your chart, map, button or graphic relies on colour alone, they may not be able to read it. This simulator shows your image the way people with protanopia (no red cones), deuteranopia (no green cones), tritanopia (no blue cones) or achromatopsia (no colour) see it, side by side with the original.
The transformation uses the scientifically established Machado et al. (2009) model applied in linear RGB, with a severity slider from mild to complete. Upload a screenshot, logo, chart or photo, switch between types, and download the simulated image. It runs entirely in your browser, so unpublished designs stay private.
Key features
Four vision types
Protanopia, deuteranopia, tritanopia and achromatopsia.
Severity slider
From mild colour weakness to full deficiency.
Side-by-side view
Original next to the simulation.
Accurate model
Machado 2009 matrices applied in linear RGB.
How to use it
- Drop your image or screenshot on the box.
- Pick a vision type and adjust the severity.
- Compare with the original; look for colours that merge.
- Download the simulated image, then fix the design.
Worked example
Example
A red/green status chart under deuteranopia → both colours look olive-brown: add labels or icons.
Who uses this tool
Designers and developers
Check UI, charts and maps for accessibility.
Teachers and publishers
Make materials readable for everyone.
Anyone with colour-vision questions
Understand what others see.
Tips for the best results
- Never rely on colour alone — add text, patterns or icons.
- Use colour pairs with strong brightness contrast, not just hue.
- Blue/orange is a safe colour pair for most types.
- Test with real users where you can.
Common mistakes to avoid
- Assuming red and green are always distinguishable.
- Using only colour to mark errors or success.
- Treating the simulation as medical diagnosis — it is a design aid.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
How accurate is the simulation?
It uses the published Machado et al. (2009) model, widely used in accessibility tools, but real perception varies between people.
Is my image uploaded?
No. Processing is local.
What is deuteranopia?
The most common deficiency: green cones do not work, so reds and greens look similar.
Can this test if I am colour blind?
No. It shows what others see; use an Ishihara-style test or an optometrist to test your own vision.
What is the severity slider?
It blends between normal vision (0%) and complete deficiency (100%) for milder colour weakness.
How can I make my design accessible?
Add labels, patterns and icons and keep strong brightness contrast between colours.