Free color blind test – online, no sign-up, works on any phone.
Red-Green Color Blind Test
Find out in 2 minutes whether you have a red-green color vision deficiency – and whether it is a red (protan) or green (deutan) weakness and how strong it is.
- ✓ Free
- ⏱ 2 minutes
- ◎ 22 test plates
💡 Turn screen brightness up and switch off night mode or blue-light filters before you start.
Which number do you see?
Your result
This online test gives a first indication only. It does not replace a diagnosis by an eye doctor or optician.
Color blindness in numbers: worldwide and in the US
Around 300 million people worldwide are color blind – most of them red-green. In the United States alone, an estimated 12.6 million people are affected. Many only find out by chance, because they have never known anything different.
Estimate: population × typical prevalence (approx. 7% of men and 0.5% of women).
How the test works
- 1
You see 22 plates made of colored dots. Each hides a number.
- 2
Tap the number you see. If you can’t see one, choose “Not sure”.
- 3
You instantly get your result: type and severity of your color vision deficiency.
Questions about red-green color blindness
What is red-green color blindness?
It is the most common color vision deficiency: about 8% of men and 0.5% of women find it hard to tell red and green tones apart. It is usually inherited and present from birth.
What is the difference between protan and deutan?
With protan (red weakness) the red-sensitive cones work less well, so reds look darker and duller. With deutan (green weakness), the most common type, the green-sensitive cones are affected and greens and reds blend into each other.
What is the Ishihara test?
The Ishihara test is the best-known color vision test, developed in 1917 by Japanese ophthalmologist Shinobu Ishihara. Numbers made of colored dots are hidden in a background of differently colored dots – people with a red-green deficiency cannot see some of them. This free online test uses the same principle.
How accurate is an online test?
The test is based on the Ishihara principle and gives a good first indication. Screens show colors differently, so only an eye doctor or optician can make a diagnosis.
Can glasses help with red-green color blindness?
Special filter glasses cannot cure color blindness, but they can make reds and greens stand out more clearly for many people with a red-green deficiency.
This online test gives a first indication only. It does not replace a diagnosis by an eye doctor or optician.