The Short Answer
You can make a rough guess at a baby's eye color from the parents' eyes, but not a reliable prediction. Eye color depends on many genes, and the old one-gene "brown beats blue" model is wrong often enough that MedlinePlus Genetics (US National Library of Medicine) calls it too simplistic. The American Academy of Ophthalmology puts it plainly: you can't predict a child's eye color just from looking at the parents' eyes.
This page has no calculator. It explains how inheritance works, what online eye color calculators do, and why their percentages should be read as rough odds.
The Genetics Behind Eye Color
Eye color is polygenic, meaning several genes shape it. The biggest effect comes from a region on chromosome 15 with two genes, OCA2 and HERC2; other genes, including SLC24A4, TYR, and IRF4, add smaller effects.
That is why the old "two blue-eyed parents can't have a brown-eyed child" rule is not always true. It is uncommon, but MedlinePlus notes that parents with blue eyes can have children with brown eyes.
What Eye Color Calculators Do (and Don't)
Most eye color calculators you will find online take the parents' (and sometimes grandparents') eye colors and apply a simplified model — usually one or two genes — to give percentages for brown, green, and blue.
Those numbers are useful as a rough sense of which outcomes are more likely. They are not a forecast: the models leave out most of the genes involved, treat "hazel" and "green" as tidy categories, and cannot see which gene variants the parents actually carry.
Where Hazel and Green Fit In
Hazel and green come from a moderate amount of pigment combined with the way light scatters in the iris, not from a simple on/off gene. A child can end up with hazel or green eyes even when neither parent has exactly that shade, depending on the combination of variants passed down — another reason calculators struggle with these colors.
Baby Eye Color Changes Over Time
Many babies are born with lighter eyes because the pigment in the iris is still developing. According to the American Academy of Ophthalmology, most babies have the eye color that will last their lifetime by about nine months, and the AAO also notes that slight changes during the first three years are not uncommon. The American Academy of Pediatrics' HealthyChildren.org adds that pigment cells take about a year to finish their work, so calling a baby's eye color before the first birthday is a gamble.
Eyes usually darken as pigment arrives. If one of your baby's eyes looks different in color from the other, see the heterochromia guide — an infant with two different eye colors should be examined by a pediatrician and an eye doctor.
From Prediction to Real Color
To know an actual eye color, look at the iris itself once the color has settled. For the inheritance side, eye color genetics explains why two brown-eyed parents can have a blue-eyed child. Our Eye Color Analyzer app (free on iOS and Android) can also give a probability-style estimate of a child's likely eye color from two parent photos — treat it the same way, as rough odds rather than a prediction.
