Science-based calculator built on Mendelian and polygenic inheritance models. Predict eye colour, hair, height, skin tone and 17 more traits , completely free, no sign-up needed.
Every tool is built on established genetic science. Click any trait below to get started instantly.
Calculate the probability of brown, blue, green, hazel, or grey eyes based on parental and grandparental eye colours using OCA2 and HERC2 gene models.
Open Calculator →Predict potential hair colour combinations including black, brown, blonde, and red using polygenic pigment inheritance and MC1R gene analysis.
Open Calculator →Calculate your child’s estimated adult height using the validated mid-parental height formula with growth percentile tracking.
Open Calculator →Explore how melanin inheritance and multiple genes combine to influence your baby’s likely skin tone, especially useful for mixed-ethnicity families.
Open Calculator →Find out whether your baby will likely have straight, wavy, curly, or coily hair based on inherited gene variants from both parents.
Open Calculator →Determine the likelihood of your baby inheriting facial dimples using classical dominant inheritance analysis applied to both parents.
Open Calculator →Discover how the MC1R gene influences freckle formation and the probability of your child developing freckles based on family history.
Open Calculator →Predict whether your baby will have attached or free earlobes using simple Mendelian dominant and recessive genetic inheritance grids.
Open Calculator →Calculate the probability of cleft chin inheritance based on dominant genetic factors passed from both parents through classical Mendelian patterns.
Open Calculator →TraitGen translates peer-reviewed genetic models into tools anyone can use. Here is how every calculator works, step by step.
Based on one brown-eyed parent carrying a blue-eye variant and one blue-eyed parent. Results update instantly when you change the inputs.
Every tool and article on TraitGen is rooted in established genetic research, not guesswork or entertainment.
Traits like earlobe type, cleft chin, dimples, and tongue rolling follow classical dominant and recessive patterns first described by Gregor Mendel in 1866. Our calculator apply these exact models updated with modern gene-mapping data.
Height, skin tone, hair colour, and eye colour are controlled by many genes working together. Our polygenic models factor in both parents and in some cases grandparents, producing probability ranges that reflect how the science actually works.
Every factual claim on this site is traceable to published genetics research from sources including the National Institutes of Health (NIH), OMIM (Online Mendelian Inheritance in Man), and peer-reviewed journals in human genetics.
All calculations happen locally in your browser. We never transmit, store, or process any genetic data you enter. Your family’s information stays entirely on your own device. This is a deliberate design and ethical commitment.
45+ in-depth articles explaining how genes work, why traits skip generations, and what modern genetics can and cannot predict.
Eye color is not a simple dominant switch. At least 16 genes are involved. Here is what actually determines whether your baby gets blue, brown, or green eyes.
Read article →A plain-language guide to how dominant and recessive inheritance patterns work, with real family examples and what they mean for your children.
Read article →Your child looks just like your grandmother but nothing like you. Here is the genetics of recessive traits and why they reappear unexpectedly across generations.
Read article →TraitGen is a genetics education platform. All calculator provide probability estimates based on established genetic models, not certainties. Our tools are not a substitute for professional genetic counselling, medical diagnosis, paternity testing, or any clinical service. If you have concerns about hereditary health conditions, please consult a qualified genetic counsellor or your healthcare provider. No personal genetic data is collected, stored, or transmitted by this website.
Our calculator provide probability estimates based on established genetic models, not guaranteed outcomes. For simple Mendelian traits the models are well-validated. For complex polygenic traits, results are probability ranges because many genes and environmental factors contribute. Think of outputs as informed estimates, not certainties.
Completely private. All calculations run locally in your browser. No data is sent to our servers, stored in a database, or shared with third parties. You can verify this by checking that the calculations still work without an internet connection once the page has loaded.
Yes, that is one of the most common uses. Expecting parents use our eye colour, hair colour, height, and skin tone predictors to explore what combinations are genetically possible. Results are always probabilities, and the real outcome will be a beautiful surprise regardless.
Mendelian traits are controlled by a single gene with clear dominant and recessive versions, such as attached or free earlobes. Polygenic traits are influenced by many genes, producing a spectrum of outcomes. Height, eye colour, and skin tone are polygenic, which is why they show so much variety even within the same family.
No. TraitGen is strictly an educational platform. Our tools are not designed for medical decisions, health risk assessments, paternity testing, or clinical use. For anything medically relevant related to genetics, please consult a certified genetic counsellor or your doctor.
39 free calculator and 45+ genetics articles. No sign-up. No cost. Just science.