How to use it
- Choose the first parent's eye color.
- Choose the second parent's eye color.
- Read the most likely color and the estimated chances.
- Remember that real eye color genetics is more complex.
Estimated chances
| Parents | Brown | Green / hazel | Blue / gray |
|---|---|---|---|
| Brown × Brown | 94% | 4.7% | 1.6% |
| Brown × Green | 75% | 22% | 3.1% |
| Brown × Blue | 75% | 12.5% | 12.5% |
| Green × Green | 0% | 94% | 6.3% |
| Green × Blue | 0% | 75% | 25% |
| Blue × Blue | 0% | 0% | 100% |
These numbers come from the model described below, not from population studies. In reality, brown-eyed parents have a better chance of a blue-eyed baby if blue eyes run in either family, and two blue-eyed parents can, rarely, have a brown-eyed child.
The two-gene model
The calculator uses a simplified model often taught in biology classes:
- Gene 1 (brown/blue): the brown version is dominant. One brown copy is enough for brown eyes.
- Gene 2 (green/blue): only matters if gene 1 has no brown copy. The green version is dominant over blue.
- Blue eyes appear only when both genes carry two blue copies.
The calculator doesn't know which hidden versions each parent carries, so it considers every genetic combination that matches their eye color as equally likely and averages the results.
Reading the example: brown and blue
Take a brown-eyed and a blue-eyed parent, the default setting. The blue-eyed parent can only pass on blue versions of both genes. The brown-eyed parent might carry two brown copies of gene 1 (then every child has brown eyes) or one brown and one blue copy (then each child has a 50% chance of not getting brown). Averaging over all the possibilities the model allows gives 75% brown, with the remaining 25% split between green and blue.
Knowing the grandparents helps: if the brown-eyed parent has a blue-eyed parent, they almost certainly carry a blue copy, and the real chance of a blue- or green-eyed child is higher than the average shown here.
Why it's only an estimate
Real eye color is a polygenic trait. The biggest single factor is a region on chromosome 15 that includes the OCA2 and HERC2 genes, which affects how much melanin the iris makes, but at least a dozen other genes contribute. That's why there are so many shades between brown and blue, why hazel eyes can look green or brown depending on the light, and why the simple model can't explain every family.
Treat the result as a fun prediction, not a forecast.
When does a baby's eye color settle?
Many babies, especially those with lighter-skinned parents, are born with blue or gray eyes because the iris has little melanin at birth. Melanin builds up over the first months, and eyes may darken to green, hazel or brown. Most of the change happens during the first year, though subtle shifts can continue for a few years. Babies born with brown eyes usually keep them.
If a baby's eyes look very different from each other, if the pupil looks white or cloudy in photos, or if you have other concerns, ask your pediatrician. This calculator is for entertainment and information only and isn't medical advice.
The calculation happens in your browser. For an inheritance calculator based on firmer rules, try the blood type calculator.
Frequently asked questions
Can two blue-eyed parents have a brown-eyed baby?
In this simple model, no. In real life it is rare but possible, because more genes are involved than the model includes.
Can two brown-eyed parents have a blue-eyed baby?
Yes. If both carry hidden blue versions, a blue-eyed child is possible; the model estimates about 1.6% when nothing else is known.
Is brown eye color dominant?
In the classic model, yes: one brown version is enough. Real inheritance is more complex, so dominance isn't absolute.
When do babies get their permanent eye color?
Most changes happen during the first year as melanin builds up in the iris; some babies' eyes keep changing subtly for a few years.
How accurate is this calculator?
It's a simplified teaching model, good for a rough idea and for fun, not for reliable predictions.
Sources
- MedlinePlus Genetics – Is eye color determined by genetics?
- The Tech Interactive (Stanford at The Tech) – How is it possible that I have blue eyes when my father has brown and my mother green?
Last reviewed: November 14, 2026 · Kitpebble editorial team
Change log
- : Sources expanded; FAQ and content reviewed.
- : Sources expanded; FAQ and content reviewed.
For general information only; not medical advice or a diagnosis. How we write and review our pages