Color Blindness Simulator

Color Blindness Simulator

The Color Blindness Simulator previews how HEX colors, interface pairs, and palettes may appear under common color vision deficiencies. It is useful for checking buttons, alerts, chart colors, dashboards, maps, form states, and brand palettes before color-only meaning creates accessibility problems.

Supported Simulation Types

This tool simulates protanopia and protanomaly for red-cone deficiencies, deuteranopia and deuteranomaly for green-cone deficiencies, tritanopia and tritanomaly for blue-cone deficiencies, plus achromatopsia and achromatomaly for grayscale-style review.

How To Use This Tool

• Use Pair mode to test text, buttons, badges, alerts, error states, and selected states.
• Use Palette mode to check charts, dashboard series, map layers, and status-color systems.
• Use Single mode to inspect one brand or UI accent color and copy its simulated HEX value.
• Move the severity slider when you need a partial simulation instead of the full matrix effect.

Why Contrast Still Matters

A color pair can look distinct in a simulation and still fail luminance contrast. After checking color vision risk here, run the same pair through the Color Contrast Checker to verify WCAG contrast thresholds for normal text, large text, and UI components.

Accessible Design Tips

• Do not rely on color alone to communicate success, warning, danger, active, inactive, or selected states.
• Add labels, icons, underlines, borders, patterns, or shape differences when colors carry meaning.
• Check hover, focus, disabled, pressed, selected, error, and loading states, not only static screens.
• Keep chart legends close to chart marks and avoid red/green-only comparisons.
• Use direct text like "Failed", "Required", or "Selected" when the state matters.

Limitations

Color blindness simulation is an approximation. Real vision, displays, browser color management, lighting, and user settings vary. Treat this as a practical screening tool, not a medical model or accessibility certification.

Related Tools

• Color Contrast Checker for WCAG AA and AAA contrast ratios.
• HEX / RGB / HSL Color Picker for color conversion, previews, and related colors.
• Color Palette Generator for complementary, analogous, triadic, and monochromatic palettes.
• HTML Beautifier for formatting interface markup before accessibility review.

References

• W3C WCAG use of color guidance
• W3C WCAG contrast minimum guidance
• Nielsen Norman Group guidance on using color in design
• WebAIM overview of color blindness and web accessibility

FAQ

Is this color blindness simulator accurate?

It uses deterministic sRGB simulation math to approximate common color vision deficiencies. It is good for screening UI risks, but real users and displays vary.

Which color blindness type should I test first?

Start with deuteranopia and protanopia because red-green deficiencies are common. Then check tritanopia and grayscale modes when colors are used in charts, maps, or status systems.

Does passing this tool mean my design is accessible?

No. Passing simulation only means the checked colors stayed reasonably distinct by this tool's distance model. You still need contrast, keyboard, screen-reader, and real-use testing.

Can I test charts and dashboards?

Yes. Paste chart colors into Palette mode to find simulated collisions between series colors, KPI states, or map categories.

Should I still run a contrast checker?

Yes. Color vision simulation and contrast testing catch different issues. Use both before shipping important UI states.