What Is the Most Common Eye Color? Over 70% of People Have It

There's a scientific reason for the most common eye color. Laurence Monneret / Getty Images

Eye contact helps build trust and communication whether in business, friendships or romantic pursuits. Its importance in human socialization means that we're more likely to take note of eye color and wonder, "What is the most common eye color?"

People with lighter eye colors may also be perceived as friendlier or more trustworthy, even though eye color is a genetic signifier largely outside of an individual's control. Having an uncommon eye color may also draw attention, even though eye color itself indicates nothing about a person's character.

Here, we break down which eye colors are more or less common in the world's population, and detail some of the science behind eye color development.

What Determines Eye Color?

Like so many other traits in the body, your eye color is determined by particular genes passed down from your parents. These genes directly affect the amount of melanin present in the blood vessels of the iris during development, giving them a trademark color.

Melanin is the same chemical which causes pigmentation of skin. Higher levels of pigmentation generally result in dark brown eyes developing, while lowers levels of pigmentation result in blue or green eyes. Much more rare expressions of color like albinism and violet eyes can be caused by genetic mutations or environmental factors.

The genes that determine eye color are also more complicated than the child having the same eye color as a parent. Two blue-eyed parents can have a baby with brown eyes, just as two brown-eyed parents can have a baby with blue eyes.

One thing we do know is that the genetic signifiers which cause blue or gray eyes are significantly more common in white populations than those of other ethnic groups. This suggests that blue eyes began as a genetic mutation somewhere in Europe, but these genes are likely to spread in other ethnic groups over generations as global populations mingle with one another.

Brown Is the Most Common Eye Color

An estimated 70 to 80 percent of the world's population has brown eyes, ranging from dark almost black shades to a lighter brown. All races and ethnic groups on Earth carry genes to express brown eyes, suggesting that we share some common genetic ancestor who also had brown eyes.

People with brown eyes make up the vast majority on non-white ethnic groups. If you sample majority Asian or African ethnic populations, you are much less to find people with an eye color other than brown.

3 Other Typical Eye Colors

Hazel Eyes (10%)

Another variation is hazel eyes. Hazel eyes account for about 10 percent of the world's population and may appear brown under dark lighting, then take on a more yellow appearance in bright light.

On closer inspection, hazel eyes may also contain flecks of green or blue inside the iris which give them a unique appearance. This type of pigmentation with light colored eyes is more common in southern European countries, North Africa and the Middle East, as well as in diaspora populations from those territories.

Blue Eyes (10%)

Blue-eyed people are relatively common in white populations while being much rarer in other ethnic groups.

Overall, blue eyes account for about 10 percent of the world's population. There is also a lot of variation among blue eyed people, as some may appear a deep, solid blue; others may appear lighter with green or brown flecks.

Gray Eyes (3%)

Gray eyes, which are typically a light blue color on closer inspection, make up for about three percent of the total population. It's likely that the same or similar genetic markers which cause blue and green eyes may also cause gray eyes in some circumstances.

Health conditions like cataracts may also cause the eyes to take on a dull gray appearance, but this not directly tied to eye color.

Green Eyes (2%)

Like blue eyes, green eyes are almost entirely unique to white populations, but they are significantly rarer than blue eyes even in those populations. Green-eyed people account for only about two percent of the total population, making them more likely to stand out in a crowd.

How Genetic Mutations Affect Eye Color

Very small portions of the population may also be host to genetic mutations which cause their eye colors to express themselves in unique ways.

Violet Eyes

A mutation to the FOXC2 genetic marker can cause a lack of pigmentation in the eyes, and people who would normally have blue eyes will instead have what appears to be a violet or purple shade. Violet eyes are exceptionally rare, with one notable example found in actress Elizabeth Taylor.

Albinism

Albinism is a mutation which can appear in several types of animal species including humans. The mutation causes little or no melanin to be present throughout the body.

Skin and hair develop to be very pale, along with red or pink eyes. The eyes appear this way due to a lack of melanin in the iris and the underlying blood vessels showing through the tissue.

Heterochromia

Heterochromia is a condition which causes one eye to be one color (like brown) and the other eye to be a different color (like blue). Heterochromia may also express itself as "slices" of color which split up one or both of the eyes.

Apart from genetic mutation, it's also possible for an injury or nerve damage sustained to one eye early in life to cause it to develop into a different color.