Color Blindness Simulator & Accessibility Checker
Preview colors, design palettes, and visual assets across all 8 forms of color vision deficiency to verify WCAG 2.1 accessible design with instant client-side execution.
At a glance
Color Blindness Simulator & Accessibility Checker is a free web tool that simulates color vision deficiencies online. It instantly checks whether text color pairs pass or fail AA/AAA standards under color blindness. Drag and drop screenshots and UI mocks to see how color-blind users perceive your product. All processing is local: nothing is uploaded, and no account is required.
100% Client-Side LMS Matrix Simulation
Color blindness models, image pixel transformations, and WCAG contrast evaluations process locally in browser memory.
Prevent Red/Green Traps
Over 8% of men and 0.5% of women have red-green color deficiency. Pairing red errors with green success buttons without icons causes critical UI confusion.
WCAG 2.1 Compliance
Ensure your designs maintain at least 4.5:1 contrast for normal text and 3:1 for large text across simulated dichromacy conditions.
In-Browser Canvas Processing
Upload screenshots, dashboards, and branding assets to simulate full color deficiency pixel-by-pixel with zero server uploads or latency.
Why Use This Color Blindness Simulator & Accessibility Checker?
How to Use Color Blindness Simulator & Accessibility Checker
Select Vision Deficiency
Choose a color vision deficiency mode (e.g. Deuteranopia, Protanopia, or Tritanopia) and adjust severity.
Test Colors or Upload Image
Explore palette swatches and contrast ratios, or upload an image to inspect simulated visual perception.
Export Results
Copy simulated hex codes, check WCAG compliance badges, or download the simulated image.
Traffic Light Red Simulation under Deuteranopia
Demonstrates how pure red is perceived by green-blind users as a dull olive-yellowish shade.
#FF0000 (Pure Red)
#8B7700 (Olive Ochre)
Technical Specifications & Engine Details
| Specification | Details |
|---|---|
| Supported Formats | TEXT/PLAIN, IMAGE/PNG, IMAGE/JPEG, IMAGE/WEBP → TEXT/PLAIN, IMAGE/PNG |
| Execution Mode | 100% Client-Side In-Browser (client) |
| Browser Requirements | Modern browser with JavaScript enabled. |
| Performance Constraints | Runs client-side in browser memory. Performance and file limits are bounded by available local device RAM. |
100% Client-Side Privacy Guarantee
Your files remain strictly on your local device. Zero data is transmitted to external servers.
Frequently Asked Questions
What is the most common form of color blindness?
Why is testing red-on-green contrast so important for UX?
Are my uploaded design images sent to an external server?
Methodology
This tool runs entirely in your browser. The example above shows a representative input and the result it produces.
Last updated .