Color Blindness Simulator
See how your color choices look to people with different types of color vision deficiency — essential for accessible design.
Frequently Asked Questions
About this calculator
Pick a colour or type a hex code and see how it looks to people with different types of colour-vision deficiency.
Roughly one in twelve men is affected, so checking your palette is part of accessible design.
How to use it
- Pick a colour.
- Press Simulate Color Blindness.
- Compare the results.
Types of colour blindness
About 8% of men and 0.5% of women have a colour-vision deficiency. Protanopia (no red cones) and deuteranopia (no green cones) make red and green hard to separate. Tritanopia (blue) is rare. Achromatopsia is full colour blindness. The simulator applies colour-transformation matrices that approximate what each group sees.
Worked example
Risky pairs
| Red and green | Hard for protanopia and deuteranopia |
| Blue and purple | Can merge in tritanopia |
| Green and brown | Often confused |
| Safe approach | Add icons, labels or patterns, not colour alone |
Tips and common mistakes
- Never use colour as the only signal (add text or icons).
- Use strong lightness differences, not just hue.
- Blue and orange are a safe pair.
- Check charts and status badges.
- Test with real users when possible.
Frequently asked questions
What is colour blindness?
Reduced ability to distinguish certain colours.
What are the types?
Protanopia, deuteranopia, tritanopia and monochromacy.
How common is it?
About 8% of men and 0.5% of women.
Is a simulation exact?
No, it is an approximation.
Why does it matter for websites?
Many people cannot tell red from green.
What is a safe palette?
One that also differs in lightness and uses labels.