Brown is by far the most common eye color in the world, belonging to roughly 70% to 80% of the global population. Blue comes in a distant second at 8% to 10%, followed by hazel and amber at about 5% each. Green is the rarest of the standard eye colors, found in only about 2% of people worldwide.
Global Eye Color Distribution
The dominance of brown eyes is hard to overstate. Nearly all people of African descent, South Asian descent, and East Asian descent have brown eyes. In East Asian populations, green eyes are exceptionally uncommon and blue eyes are virtually absent. Brown is the default human eye color in a biological sense: it reflects a high concentration of pigment in the iris, which is the ancestral state for our species.
Blue eyes are concentrated primarily in populations of European descent, though they appear in scattered frequencies elsewhere. Hazel eyes, which blend brown and green with occasional gold flecks, account for about 5% of people globally. Amber eyes, a solid golden or coppery color distinct from hazel, sit at roughly the same frequency. Green eyes are the clear outlier, with just 2% of the world’s population carrying them.
How Eye Color Varies by Region
Where you look in the world dramatically changes what “common” means. A large literature review covering European and Central Asian countries illustrates this well. In Iceland, nearly 75% of people have blue or gray eyes, and fewer than 10% have brown eyes. The Netherlands is similar: about 61% blue or gray, only 22% brown. In Great Britain, blue and gray eyes edge out brown at roughly 43% versus 32%, with another 25% in the intermediate range that includes green and hazel.
Move south and east, and the picture reverses. In Armenia, 80% of the population has brown or hazel eyes and only 3% has blue. In Uzbekistan, those figures shift even further: over 90% brown, about 3% blue. Kazakhstan follows a nearly identical pattern. France sits somewhere in the middle, with 34% brown, 44% intermediate (green, hazel, or yellow tones), and 22% blue.
These regional differences are the product of thousands of years of population history, migration, and natural selection in different light environments.
Eye Color in the United States
The U.S. population is more diverse than most European countries, and the eye color distribution reflects that mix. A massive dataset of over 235 million driver’s license records from 31 states found brown or black eyes in 53% of holders. Blue came in at 23.7%, hazel at 10.3%, green at 9%, and gray at less than 1%. Another 3.3% were recorded as other colors.
That means if you live in the U.S., roughly one in four people you meet has blue eyes, and about one in eleven has green. Green eyes are far more common in the U.S. than they are globally (9% versus 2%), largely because of the country’s heavy European ancestry.
What Determines Your Eye Color
Eye color comes down to how much pigment sits in the front layer of your iris and how tightly it’s packed. The iris contains two types of pigment: one that’s black or brown and one that’s red or yellow. But more important than the ratio of these two pigments is the density of pigment-producing structures in the iris. There’s a smooth gradient: as pigment density increases, eye color shifts from blue to gray to green to hazel to brown.
Two genes on chromosome 15 do most of the heavy lifting. One produces a protein that helps pigment-producing structures in cells mature properly. The more functional protein you produce, the more pigment ends up in your iris. Variations in this gene reduce the protein’s output, which means less pigment and lighter eyes. The second gene acts like a dimmer switch, controlling how active the first gene is. A specific variation in this regulatory gene can dial down pigment production, pushing eye color toward blue.
That said, eye color isn’t a simple two-gene trait. At least 16 genes contribute to the final result, which is why two brown-eyed parents can occasionally have a blue-eyed child. The subtle differences between gray, hazel, and green eyes come from individual variation in pigment ratios and the way light scatters through the iris’s internal structure. Blue eyes, for instance, contain very little pigment. The blue appearance is actually a trick of light scattering, similar to why the sky looks blue.
When Eye Color Develops
Babies aren’t born with their permanent eye color. Many newborns, particularly those of European descent, start with blue or gray eyes because their irises haven’t yet accumulated much pigment. Color typically begins shifting between 3 and 9 months of age, most often around the 6-month mark. But the process isn’t always fast. It can take up to three years for a child’s eye color to reach its final shade. Eyes almost always darken rather than lighten over time, because pigment is being added, not removed.
Babies born with dark brown eyes are unlikely to see much change, since their irises already have substantial pigment from the start. The biggest surprises tend to happen in lighter-skinned families, where an infant’s initial blue may settle into green, hazel, or brown as the months pass.
The Rarest Eye Colors
Green takes the title among standard eye colors at 2% of the global population. But there are even rarer variations. Gray eyes, distinct from blue, appear in less than 1% of the U.S. population and are concentrated in people of Northern and Eastern European ancestry.
Heterochromia, the condition of having two different-colored eyes (or two colors within the same eye), affects only about 1% of people worldwide. It can be inherited or caused by injury, disease, or certain medications. Most cases are harmless and purely cosmetic.
Red or violet eyes are the rarest of all and are almost exclusively associated with albinism. In people with very little or no pigment in the iris, blood vessels behind the eye become visible, giving the iris a red or pinkish hue. Under certain lighting conditions, this can appear violet. True violet or red eyes outside of albinism are so uncommon that reliable statistics on their frequency don’t exist.