Eye Colour Calculator
Estimate a baby's eye colour chances from the parents' (and grandparents') eye colours.
Will the baby have brown, green or blue eyes? This calculator gives you a playful, rough estimate. You enter the eye colours of both parents and, optionally, of the grandparents, and the tool shows approximate probabilities for brown, green and blue eyes in a child. Grandparents' colours help because they hint at hidden (recessive) variants that parents may carry without showing them.
The calculator uses a simplified model that has traditionally been used in teaching: brown tends to dominate over green and blue, and green over blue. In reality, eye colour is polygenic: it depends on many genes, with OCA2 and HERC2 playing the largest roles, which together control how much melanin pigment the iris contains. This is why two blue-eyed parents can, occasionally, have a child with green or even brown eyes, and why shades such as hazel, grey and amber do not fit neatly into any simple scheme.
Many babies of European ancestry are born with blue or grey eyes that darken over the first months as melanin builds up; the final colour is usually settled somewhere between 6 months and 3 years. Treat the result as a fun estimate, not a genetic test or a statement about parentage.
How to use
- Select the eye colour of the first parent: brown, green (including hazel) or blue (including grey).
- Select the eye colour of the second parent.
- Optionally add the eye colours of the grandparents on both sides to refine the estimate.
- Press calculate to see the probabilities for brown, green and blue eyes.
- Read the explanation below the result to understand why real outcomes can differ.
Reading your result
The percentages show how likely each colour is under the simplified model, not a guarantee. A 75% chance of brown eyes still leaves a real chance of another colour, and rare outcomes outside the model are possible because of the many genes involved. Remember too that a newborn's eye colour can still change during the first years of life, so an early result is not final.
Eye colour itself is not a health issue. However, see a doctor if a baby's eyes are of clearly different colours (heterochromia) that appears or changes later, if one pupil looks white or unusual in photos, or if an adult's eye colour changes noticeably, because these can occasionally point to eye disease.
Caution: For entertainment and education only. It is not a genetic test and cannot prove or disprove parentage. Sudden change in eye colour or a white pupil reflex needs medical assessment.
Frequently asked questions
Can two blue-eyed parents have a brown-eyed child?
It is uncommon but possible, because eye colour is controlled by several genes rather than a single one. Simple models cannot fully predict it.
When do babies get their final eye colour?
Most changes happen in the first year, and colour usually settles by about age 3, although subtle shifts can continue later.
Is eye colour linked to eye health?
Lighter irises let more light through and may be associated with more glare sensitivity and slightly higher risk of some conditions, so UV protection is sensible for everyone.