Baby Eye Color Calculator
Select both parents' eye colors to see the probability that your baby will have brown, hazel, green, or blue eyes. Add grandparent eye colors for a more refined estimate - if a brown-eyed parent has a blue-eyed grandparent, they likely carry a hidden recessive allele that shifts the odds. The percentages come from a simple population-level model built around HERC2 and OCA2, the two genes behind most human eye color variation. This is a for-fun tool for general interest, not medical, genetic, or diagnostic advice, and no clinical body publishes eye color odds of this kind.
How eye color genetics works
Eye color is determined by the amount and type of melanin (pigment) in the iris. More melanin produces brown eyes; less produces green or hazel; very little produces blue or gray, which appear blue because of the way low-density irises scatter light. Although early genetics textbooks presented brown as simply dominant over blue, modern research has identified more than 16 genes that influence eye color. The two most important are OCA2 and HERC2 on chromosome 15. A single variant in HERC2 switches OCA2 on or off and accounts for most blue-versus-brown variation, but dozens of modifier genes fine-tune the result, which is why siblings can have noticeably different eye colors despite sharing the same parents.
Why grandparents matter for eye color prediction
A brown-eyed parent may carry a "hidden" copy of a low-melanin allele inherited from a blue- or green-eyed grandparent. If both parents carry such a recessive allele, their child has a real chance of lighter eyes even though both parents look dark-eyed. This calculator accounts for that possibility: when you add grandparent data and one grandparent has blue or green eyes, the probability of lighter outcomes increases noticeably. Without grandparent information the tool uses only the parents' observed phenotypes, which gives a reasonable but slightly less precise estimate.
When does a baby's eye color become permanent?
Most babies of European descent are born with blue or gray eyes that deepen over the first six to twelve months as melanin production ramps up. By about twelve to eighteen months the color is largely settled, though subtle shifts can continue until age three. Babies with more melanin at birth, common in African, Asian, and South Asian populations, tend to have brown eyes from the start that remain stable. A sudden change in eye color outside of infancy is worth mentioning to a doctor, as it can occasionally indicate a medical condition.
Brown, hazel, green, and blue: what sets them apart
Brown eyes have the highest melanin density and are the most common globally, carried by about 55-80% of people worldwide. Hazel eyes have a moderate but uneven distribution of melanin, giving a mix of brown, gold, and green tones that can look different under different lighting. Green eyes, carried by roughly 2% of people worldwide, result from a small amount of melanin plus structural light-scattering - they contain no green pigment. Blue and gray eyes have the least melanin; the color comes entirely from the way light interacts with the collagen fibers of a largely unpigmented iris, the same principle that makes the sky look blue.
Common parent eye color combinations and typical probabilities
| Parent 1 | Parent 2 | Brown | Hazel | Green | Blue |
|---|---|---|---|---|---|
| Brown | Brown | 75% | 13% | 6% | 6% |
| Brown | Hazel | 50% | 38% | 6% | 6% |
| Brown | Green | 50% | 12% | 25% | 13% |
| Brown | Blue | 50% | 12% | 13% | 25% |
| Hazel | Hazel | 25% | 50% | 12% | 13% |
| Hazel | Green | 13% | 38% | 38% | 11% |
| Hazel | Blue | 13% | 38% | 13% | 36% |
| Green | Green | 0% | 13% | 75% | 12% |
| Green | Blue | 0% | 13% | 50% | 37% |
| Blue | Blue | 0% | 1% | 1% | 98% |
Approximate percentage chances from this calculator's own population-level model, offered for general interest. No clinical or genetics body publishes an official parent-phenotype eye color table, so these are illustrative rather than validated figures. Grandparent eye colors can shift them by up to 20 percentage points.
Frequently asked questions
Can two blue-eyed parents have a brown-eyed baby?
It is very rare but genetically possible. If an ancestor introduced a brown-eye allele that passed silently down the family line, both blue-eyed parents could carry it without showing it. The chance is well under 1%, which is why the table above rounds it to 0% rather than treating it as a realistic outcome.
Can two brown-eyed parents have a blue-eyed child?
Yes - roughly 6% chance with the most conservative estimates. Each parent would need to carry a low-melanin allele from a lighter-eyed ancestor. If one or both parents have blue- or green-eyed grandparents, the probability rises considerably.
How accurate is this eye color calculator?
Treat it as a fun estimate, not a test. It works from parental phenotype alone, which is far less information than a genetic test uses, and no published study reports an accuracy figure for parent-phenotype eye color prediction. For context, the IrisPlex DNA test reads six eye color SNPs directly and still reports roughly 90% accuracy for blue and brown but only about 11% for intermediate shades such as hazel and green. A calculator working from eye color alone will do no better, so the odds here are indicative rather than predictive.
At what age is eye color permanent?
For most babies, eye color is settled by 12-18 months of age. The iris produces melanin progressively during infancy, so eyes that start out blue or gray often darken toward green, hazel, or brown in the first year. Very dark brown eyes present at birth tend to stay brown. Subtle shifts in shade can continue until around age three.
Why do siblings sometimes have different eye colors?
Each child inherits a random 50% of each parent's DNA. If both parents carry alleles for multiple eye colors - for example both carry one brown and one blue variant at the HERC2/OCA2 locus - each sibling's combination is an independent draw. This is why two children from the same parents can end up with notably different eye colors.
Is hazel closer to brown or green?
Hazel is its own category with moderate, uneven melanin distribution. The iris typically contains patches of brown, gold, amber, and green that shift in appearance under different lighting conditions. For genetics purposes, hazel behaves as an intermediate: hazel-eyed individuals can produce both darker and lighter outcomes in their children.
What do I select if a grandparent's eye color is unknown?
Select "Unknown" and the calculator will use only the parental phenotypes for that side of the family. The grandparent fields are optional; leaving them as Unknown simply prevents any grandparent-based adjustment from being applied, giving you the standard phenotype-based estimate.
Sources
- Sturm RA et al. (2008). A Single SNP in an Evolutionary Conserved Region within Intron 86 of the HERC2 Gene Determines Human Blue-Brown Eye Color. American Journal of Human Genetics.
- Simcoe M et al. (2021). Genome-wide association study in almost 195,000 individuals identifies 50 previously unidentified genetic loci for eye color. Science Advances.
- Walsh S et al. (2011). IrisPlex: a sensitive DNA tool for accurate prediction of blue and brown eye colour in the absence of ancestry information. Forensic Science International: Genetics. Shows that even direct SNP typing predicts intermediate eye colours poorly.