Baby eye color: what can we expect?
Pick each parent’s eye color. The baby eye color calculator lists the eye colors your baby can have and the chance of brown, green and blue eyes, using the two-gene model geneticists use to teach eye color.
- Possible eye colors
- Brown, green or blue
Your baby’s eyes could be: Brown, green or blue.
- Chance of brown eyes
- 50% to 100%
- Chance of green or hazel eyes
- 0% to 50%
- Chance of blue or grey eyes
- 0% to 50%
Possible eye colors: Brown, green or blue. Your baby’s eyes could be: Brown, green or blue.
How to calculate
Gives the eye colors a baby can have from the parents’ eye colors, with the chance of brown, green and blue eyes by the two-gene model of eye color.
Example with the default inputs (Parent 1 eye color Brown, Parent 2 eye color Blue or grey): Your baby’s eyes could be: Brown, green or blue.
Method: Brown = at least one BEY2 brown allele; green = no brown allele and at least one GEY green allele; blue = neither. Each parent passes each allele with chance 1/2.
- This is the two-gene teaching model. Eye color depends on many genes, so real children can have colors the model rules out, such as brown eyes from two blue-eyed parents.
- A parent known only by eye color may have several genotypes, so each chance is shown as the lowest to the highest over them.
- Hazel counts as green and grey as blue.
Worked examples
Each example is checked against the calculator on every build.
- Parent 1 eye color Blue or grey, Parent 2 eye color Blue or grey gives Possible eye colors Blue only, Chance of brown eyes 0%, Chance of green or hazel eyes 0%, Chance of blue or grey eyes 100%.Source: The Tech Interactive, Ask a Geneticist, Which eye color alleles do I have? (Patel, 2005: in the two-gene model, a working copy of BEY2 gives brown eyes whatever GEY has; with no working BEY2, a working GEY gives green; with neither, blue), https://www.thetech.org/ask-a-geneticist/articles/2005/ask108/ (retrieved 2026-10-03)
- Parent 1 eye color Green, with a blue-eyed parent, Parent 2 eye color Blue or grey gives Possible eye colors Green or blue, Chance of brown eyes 0%, Chance of green or hazel eyes 50%, Chance of blue or grey eyes 50%.Source: The Tech Interactive, Ask a Geneticist, Which eye color alleles do I have? (Patel, 2005: in the two-gene model, a working copy of BEY2 gives brown eyes whatever GEY has; with no working BEY2, a working GEY gives green; with neither, blue), https://www.thetech.org/ask-a-geneticist/articles/2005/ask108/ (retrieved 2026-10-03)
- Parent 1 eye color Brown, with a blue-eyed parent, Parent 2 eye color Blue or grey gives Possible eye colors Brown, green or blue, Chance of brown eyes 50%, Chance of green or hazel eyes 0% to 25%, Chance of blue or grey eyes 25% to 50%.Source: The Tech Interactive, Ask a Geneticist, Which eye color alleles do I have? (Patel, 2005: in the two-gene model, a working copy of BEY2 gives brown eyes whatever GEY has; with no working BEY2, a working GEY gives green; with neither, blue), https://www.thetech.org/ask-a-geneticist/articles/2005/ask108/ (retrieved 2026-10-03)
- Parent 1 eye color Brown, Parent 2 eye color Brown gives Chance of brown eyes 75% to 100%, Chance of green or hazel eyes 0% to 25%, Chance of blue or grey eyes 0% to 25%.Source: The Tech Interactive, Ask a Geneticist, Which eye color alleles do I have? (Patel, 2005: in the two-gene model, a working copy of BEY2 gives brown eyes whatever GEY has; with no working BEY2, a working GEY gives green; with neither, blue), https://www.thetech.org/ask-a-geneticist/articles/2005/ask108/ (retrieved 2026-10-03)
How it works
Two genes. BEY2 has the alleles B (brown) and b (blue); GEY has G (green) and g (blue). Eye color: brown with at least one B; green with bb and at least one G; blue with bb and gg.
Parent choices and the genotypes they allow:
| Choice | Genotypes |
|---|---|
| Brown | BB or Bb, each with GG, Gg or gg (6 genotypes) |
| Brown, with a blue-eyed parent | Bb with Gg or gg |
| Green or hazel | bb GG or bb Gg |
| Green, with a blue-eyed parent | bb Gg |
| Blue or grey | bb gg |
One cross. Each parent passes one allele of each gene, each with chance 1/2, and the two genes are passed independently. For one gene, the chance of at least one dominant allele is (the number of the 4 allele pairs with a capital letter) ÷ 4. With b = that chance for BEY2 and g = that chance for GEY: brown = b; green = (1 − b) × g; blue = (1 − b) × (1 − g).
Ranges. The calculator works out the chances for every pair of genotypes the two parents could have and shows, for each color, the lowest to the highest chance (x%, or x% to y% when they differ). Possible eye colors lists the colors whose highest chance is above 0, in the order brown, green, blue, written “Brown, green or blue”, “Green or blue”, or “Blue only” (first letter capital).
Assumptions. This is the two-gene teaching model; real eye color involves many genes.
Worked examples by hand
Blue × blue. bb gg × bb gg: every child is bb gg, blue 100%.
Green with a blue-eyed parent × blue. bb Gg × bb gg: BEY2 is always bb (brown 0%). GEY gives Gg or gg, half each: green 50%, blue 50%.
Brown with a blue-eyed parent × blue. Bb × bb gives Bb half the time: brown 50%. The other half are bb: with Gg × gg, half of those get G (green 25%, blue 25%); with gg × gg, none do (green 0%, blue 50%). So green 0% to 25% and blue 25% to 50%.
Brown × brown, genes not known. BB × anything gives brown 100%; Bb × Bb gives bb a quarter of the time, so brown is 75% to 100%. With Bb GG × Bb GG the quarter that is bb is all green (25%); with Bb gg × Bb gg it is all blue (25%). So green and blue are each 0% to 25%.
Other questions people ask
How is eye color inherited?
In the two-gene model, one gene (BEY2) has a brown and a blue allele, and brown is dominant. A second gene (GEY) has a green and a blue allele, and green is dominant over blue. Any brown allele gives brown eyes; with no brown allele, any green allele gives green; with neither, blue.
Can two blue-eyed parents have a brown-eyed baby?
Not in the two-gene model, which gives blue eyes only. In real life it is uncommon but possible, because eye color depends on many genes. MedlinePlus Genetics notes that the old one-gene rule was too simple.
Why does the calculator show a range like 0% to 25%?
A brown-eyed parent may carry hidden blue or green alleles, or not, and eye color alone does not tell which. The calculator works out every set of genes the parents could have and shows the lowest to the highest chance. Knowing that a parent has a blue-eyed parent narrows it.
What does “with a blue-eyed parent” change?
A blue-eyed person passes only blue alleles. So a brown-eyed parent whose mother or father has blue eyes must carry one blue BEY2 allele (Bb), and a green-eyed parent with a blue-eyed parent must be Gg. That turns some ranges into single numbers.
How accurate is this?
It is a teaching model, not a test. The Tech Interactive notes that at least 50 genes play a part, so a real baby can have a color the model gives as 0%. Use it for fun and to learn how dominant and recessive alleles work.
Where do hazel and grey eyes fit?
The model has only three colors. The calculator counts hazel as green and grey as blue.