Baby Eye Color Calculator

Eye color depends on how much melanin, a brown pigment, sits in the front layers of the iris. Brown eyes have a lot of it, and blue eyes have much less¹. Your baby inherits the genes that control this pigment from both parents, so eye color can be predicted as odds, never as a sure thing.

What Baby Eye Color Probability Measures

This calculator gives the chance that your baby's settled eye color falls into each of three groups: brown, green or hazel, and blue or gray. It does not predict the color at birth, which often changes in the first year. It is not a genetic test, and eye color cannot show who a baby's biological parents are.

The Formula

Chance of each eye color = sum over the baby's possible gene combinations of (chance of that combination) x (chance of that eye color with that combination)

Chance of each combination = what Parent 1 passes on x what Parent 2 passes on (one version of each gene, picked at random)

What each parent likely carries = estimated from their own eye color and any grandparents entered, using Bayes' rule (a standard way to update odds with new facts)

The model follows two genes. The first is a single DNA letter in the HERC2 gene that acts as a key switch between blue and brown eyes². The chance of each eye color for each HERC2 combination comes from 3,168 people in Queensland, Australia, mostly adolescent twins and their families of northern European descent, whose eye color was mostly rated by a research nurse². The second gene is a stand-in for the many other genes that tip non-brown eyes toward green or hazel. It is not a named gene, and its frequency is set so the model matches the same study.

The model also uses each family's background, because the blue-linked version of HERC2 is common in northern Europe and rare in most of the world. Its frequency comes from the 1000 Genomes Project⁸: about 79% in northern and western Europeans, 37% in southern Europeans, 20% in samples from the Americas, 14% in African Americans, 7% in South Asians, 3% in Africans and 0.2% in East Asians. In mainly non-European families, where brown eyes are the norm, a person with a brown-linked copy is counted as brown 99% of the time. Mixed backgrounds are blended using average European ancestry⁹.

How This Calculator Computes Your Result

Choose each parent's natural eye color: brown, hazel, green, blue or gray. You can also add up to four grandparents, or leave them as Not sure, which has the same effect as leaving them out. Then choose each parent's family background. Not sure uses a European average. A parent with light eyes is treated as having a European background, because light eyes are rare elsewhere. Hazel is counted with green, and gray with blue, because the source study grouped them that way².

The result is three percentages, rounded to whole numbers that add up to 100. No color is ever impossible, so very small chances show as under 1%, never 0%.

What Your Result Means

The highest bar is the most likely color group, not a promise. When the top two are within 5 points, the calculator calls it a close call. This table shows results for parents only, with family background left as Not sure and no grandparents entered:

These numbers fit guidance from the American Academy of Pediatrics (AAP): two blue-eyed parents are very likely, but not certain, to have a blue-eyed child, and a brown-eyed and a blue-eyed parent give roughly even odds³. Grandparents shift the result. For two brown-eyed parents, one blue-eyed grandparent raises the blue chance from 13% to 17%, as the AAP's advice suggests³.

Why Family Background Matters for Brown-Eyed Parents

In families of northern European descent, brown-eyed parents often carry a hidden blue-linked copy of HERC2, and in that group even one blue-linked copy often gives green or hazel eyes instead of brown: only 55% of people with one copy had brown eyes². In most of the world the blue-linked copy is rare⁸, so two brown-eyed parents almost always have a brown-eyed baby. This table shows two brown-eyed parents from the same background, with no grandparents entered:

Simple answers that give two brown-eyed parents at least a 75% chance assume one brown-linked copy always gives brown eyes. The Queensland data show that is not true for families of European descent², which is why those families get lower numbers.

Why Two Blue-Eyed Parents Can Have a Brown-Eyed Baby

The old one-gene model says brown is dominant and blue is recessive, so two blue-eyed parents could only have blue-eyed children. Researchers now know this model is too simple, and blue-eyed parents can have brown-eyed children, though it is uncommon¹. A region on chromosome 15 that holds the HERC2 and OCA2 genes plays a major role, and other genes play smaller roles¹. A 2021 study of 192,986 people of European descent found 61 regions of DNA linked to eye color, and the common variants it found explained only about half (53.2%) of the differences between people⁴.

Old family studies show the same pattern. In one, 1 of 52 children of two blue-eyed parents had brown eyes, and in another, 26 of 223 had eyes that were not blue⁵.

How Baby Eye Color Changes in the First Year

Not all babies are born with blue eyes. In a Stanford study of 192 healthy newborns, 63% had brown eyes at birth, 21% blue and 6% green or hazel, and about 10% were hard to call⁶. Blue eyes were common in white newborns (55%) but rare in Asian newborns (2%)⁶. So the idea that babies start out blue or gray mostly fits families of European descent.

In the first months, a baby's eyes may look blue-gray and then get darker as pigment develops⁷. The pigment cells take about a year to finish their work, and the change slows after about 6 months, though it can continue³. Most babies have their lasting eye color by about 9 months⁷. Until then, blue or gray eyes may still turn green, hazel or brown.