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Color Blindness Simulator: Protanopia, Deuteranopia, Tritanopia

This free color blindness simulator shows how a color looks to people with protanopia, deuteranopia, tritanopia and achromatopsia. Check whether two colors stay different for them.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

Color blindness changes how people tell colors apart. About 8 percent of men cannot easily tell some reds, greens or browns apart. A chart that relies on red versus green can be unreadable to them.

Enter one color, or two to compare. The tool shows what each looks like for four types of color vision, so you can see whether your pair is still distinct.

How to Use This Tool

  1. Type the first color.
  2. Optionally type a second color to compare.
  3. Press Simulate.
  4. Look at each row: if the two colors become the same, the pair is a risk.

How the Calculation Works

Each color is converted to linear RGB and multiplied by a 3 by 3 matrix for each type of color vision, based on Machado et al. (2009). The result is converted back to sRGB. Achromatopsia is simulated as a grey with the same luminance.

Worked Example

Red #e11d48 and green #16a34a look very different to normal vision, but with deuteranopia both become muddy yellow-browns that are hard to tell apart.

Common Uses

  • Checking charts and maps.
  • Designing status colors and badges.
  • Accessibility reviews.
  • Choosing safe color pairs.

Tips and Common Mistakes

  • Add shapes, labels or patterns, not only color.
  • Blue and orange are a safe pair for most types.
  • Also check text contrast with the contrast checker.

Next, you may need the color contrast checker, color difference calculator, color palette generator, color converter.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

About 1 in 12 men and 1 in 200 women have some form of red-green color blindness. Blue-yellow and total color blindness are much rarer.
Protanopia is the lack of working red cone cells and deuteranopia the lack of green ones. Both make reds and greens look similar and muddy.
A rare lack of blue cones. Blues look greener and yellows look pinkish or light grey.
It uses the Machado, Oliveira and Fernandes 2009 matrices at full severity. It is a good guide, but real vision varies between people.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.