Baby Eye Color Calculator

Welcome to the baby eye color calculator, a tool that will help you to predict your baby's eye color. And not just that, you may also use it to understand the possibilities of eye color genetics based on the parent's eye colors (some assumptions were made, see below).

Have you ever been curious about:

• When babies' eyes change color?
• Can brown-eyed parents have a blue-eyed baby? 👁️👁️
• What color eyes will my baby have? or
• How 3-allele Mendelian genetics works?

If so, continue to read all about our baby eye color predictor!

💡 Disclaimer. Our calculator models the eye color problem as a 3-allele Mendelian schema. Keep in mind this is a simplification because eye color is, in fact, a polygenic trait that is not yet fully understood by science. According to the current knowledge, there are about 16 different genes involved in the process. The results returned by our tool are, therefore, necessarily, only an approximation.

A specific set of genes determines the eye color and their tendency to express as dominant or recessive genes. The different variants of a gene are known as alleles. You can learn more about alleles in our allele frequency calculator.

Eye color genetics is more complicated than they seem due to the involvement of multiple genes that determine eye color. The brown eye allele is the most dominant one, compared to blue and green. And the green eye allele is dominant to blue. Hence blue is considered the most recessive of the gene alleles passed on to the next generation. But this pattern is the reason why parents with the same eye color can still have a different eye color baby. For instance, parents with brown eyes have a chance of green- or blue-eyed babies.

An exciting phenomenon regarding eyes and eye color is heterochromia. It is a harmless mutation in which a person is born with different colored eyes. Isn't nature truly amazing?

The baby eye color calculator is a convenient and time-saving tool that will help you to predict your baby's eye color.

Whether you are a first-time parent or getting ready for your next bundle of joy and trying to know everything you can beforehand, you are in the right place.

We understand that knowing the color of your baby's eyes is significant to you. So, the only thing you need to know to use our tool is the eye colors of both parents.

Let's walk through the steps.

1. From the drop-down, input the color of the father's eyes.
2. Next, input the color of the mother's eyes. and
3. As a result, the calculator displays the possibilities of the eye color the baby can have in percentages.

These results are, by default, under the following assumptions:

• A brown-eyed parent has a 50% chance of having a brown and blue allele and a 50% chance of having a brown and green allele; and

• A green-eyed parent has a green and blue allele.

These assumptions can be changed in the advanced mode of our baby eye color calculator. Read on to understand why we need such assumptions and how they influence the results.

Distributions of allele combinations

Recall that in Mendelian genetics, we need to know the genotype of a parent to predict what traits will be inherited by his or her offspring. In the current context, if you tell us that a parent has blue eyes, we know 100% (s)he has a blue-blue allele. However, if you tell us that (s)he has brown eyes, we know there must be two brown alleles OR one brown and one green OR maybe one brown and one blue. But we have no way of knowing which option is the true one!

Consequently, to make any calculations, we need to assume some probability distribution: for instance, we can assume it's 33% brown-brown, 33% brown-blue, and 33% brown-green. This uniform distribution would reflect our ignorance regarding the genes underlying the brown eyes of a parent.

However, in the context of predicting baby eye color, a more widespread approach is to assume the uniform distribution on heterozygotic combinations (two different alleles, i.e., brown-green, brown-blue, green-blue) and exclude, that is, assume zero chance, the homozygotic combination (two identical alleles, i.e., brown-brown).

Why do we use such a strange distribution? People with homozygotic combinations exist, don't they?

They do! To understand the reason behind this assumption, note that if just one parent had brown-brown genes, then the kid is 100% sure to have brown eyes no matter what genes the other parent provides! In other words, increasing the probability of the brown-brown combination of either parent increases the chances of a kid inheriting the dominant brown eyes.

As a result, by excluding the homozygotic brown-brown combination, we estimate from below the kid's probability for brown eyes and from above the probability for blue and green eyes. In other words, if both parents have brown eyes, the kid has at least a 75% probability of brown eyes and, at most, a 25% probability of blue or green eyes. If we allowed the homozygotic brown-brown combination, the probability of a brown-eyed kid would only increase.

The same principle stands behind excluding the homozygotic green-green combination of alleles. The probability of green eyes in a baby is estimated from below and blue eyes from above.

If you think you do not have access to or are going to be in a situation where you won't be able to use our baby eye color predictor, then we suggest it would be wise to maintain a baby's eye color chart.

As we've explained in the previous section, some assumptions about the distribution of genotypes are hidden behind each baby's eye color chart.

Here is the chart of possible eye colors in babies under the assumption that the parents can have only heterozygotic combinations of allele (homozygotic combinations are excluded!), and each such combination is equiprobable.

This baby's eye color chart is what you've most certainly already seen somewhere as THE chart for baby eye color because, as we've mentioned above, it uses the most popular assumption about the allele. See the previous section for details.

For comparison, below we include the chart of possible eye colors in babies, assuming that each combination of allele in each parent (including homozygotic) is equiprobable.

The parents' eye color combination determines the baby's eye color. Even though eye color genetics are complicated, if you are both blue-eyed, your kid will most likely have blue eyes.

If your partner is:

• Brown-eyed, your baby can have brown (most probable) but also blue or green eyes; (yes!) and
• Green-eyed, your baby can have blue or green eyes.

A baby's eyes change color during the first few months of life.

Some children are born with grey or greyish-blue eyes, rarely their permanent eye color.

With the passage of time and exposure to light, the eyes develop pigment and show their true colors.

Yes, two brown-eyed parents can have a blue-eyed baby. Theoretically speaking, there is a 6%-7% chance of a baby having blue eyes when both the parents have brown-colored eyes.

If both parents have a pair of brown eyes and both have recessive blue genes, they may pass on the recessive blue gene to their child. Then the baby can have blue eyes.

If you are green-eyed but both your parents are brown-eyed, there is nothing to worry about because two brown-eyed parents can give birth to a green or blue-eyed kid, even if a brown-eyed baby is more likely. So there is no need to be concerned 😉 because you did get your eyes from your parents, just a less likely combination.