Color blindness checks for UI design
Color Blindness Simulator helps teams find color-only communication problems before users encounter them in charts, forms, alerts, maps, and status-heavy interfaces.
Color & Design Tools
Color Blindness Simulator
Preview color shifts for common color-vision deficiencies.
Use the tool
Use Color Blindness Simulator to preview how a palette, screenshot, or UI color choice may appear under common color vision deficiencies.
Use the tool
Upload image and preview it under different color-vision conditions.
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Why use Color Blindness Simulator
- Review charts, badges, alerts, buttons, and status colors that rely on hue differences.
- Check whether key UI information remains understandable without normal color perception.
- Test palette candidates before adding them to a design system.
- Prepare accessibility review notes for designers, developers, and product teams.
About this tool
Do not rely on color alone
Simulation can reveal when red and green, blue and purple, or similar tones become hard to distinguish. Add labels, icons, patterns, and text cues for important meaning.
Use with contrast testing
Color blindness simulation and contrast checking solve different problems. Use both when reviewing accessible palettes, data visualization, and product UI states.
Example usage
Input
Success #22C55E, warning #F59E0B, error #EF4444
Output
Simulation notes showing which status colors need labels or stronger separation.
Practical guide for Color Blindness Simulator
Best practices
- Test any UI where color communicates status, category, severity, or selection.
- Pair color with labels, icons, shapes, or patterns for important meaning.
- Run contrast checks in addition to color blindness simulation.
Common mistakes
- Using red and green as the only difference between critical states.
- Testing the palette but not the actual UI composition.
- Assuming simulation replaces feedback from users with accessibility needs.
How this tool works
Step 1
Open Color Blindness Simulator and review the default example input.
Step 2
Paste your own input or upload source data when required.
Step 3
Run Color Blindness Simulator to generate output instantly in the browser.
Step 4
Verify the output using the preview and formatting helpers on the page.
Step 5
Copy the final result and continue with a related tool if needed.
Related tools
Use related links to continue your workflow and keep your output consistent across ToolHarbor pages.
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FAQ
What does Color Blindness Simulator show?
It previews how colors may shift under common color vision deficiencies so risky hue-only differences become easier to spot.
Does simulation exactly match every user experience?
No. It is an approximation. Individual vision varies, but simulation is still useful for catching obvious accessibility risks.
What UI elements should I test?
Test charts, status badges, alerts, buttons, maps, form validation, focus states, and any color-coded information.
How do I fix a failing color-only design?
Add text labels, icons, patterns, stronger luminance contrast, or different shapes so meaning is not carried by hue alone.