Girl predicted height: mom 155cm, dad 168cm
Here’s the mid-parental height estimate for a girl with a mother at 155cm and a father at 168cm.
Different parent heights? Use the height calculator above.
About the height calculator
This calculator estimates a child's predicted adult height using the mid-parental height method, a well-known formula from pediatric growth literature. It starts by averaging both parents' heights, then adjusts for the typical height difference between adult men and women: for boys, add 13cm to the average and the result is the midpoint estimate; for girls, subtract 13cm instead. In formula form: boys = (father's height + mother's height + 13) ÷ 2, and girls = (father's height + mother's height − 13) ÷ 2.
The 13cm adjustment isn't arbitrary — it reflects the average adult height gap between men and women observed across large population studies, and it's what allows the same two parent heights to produce a sensible estimate for either a son or a daughter.
The midpoint number alone is not the whole picture, which is why this calculator also shows a typical range of plus or minus 8.5cm around it. That range represents roughly a 68% confidence interval — in other words, about two-thirds of children with those exact parent heights end up somewhere within that band as adults, while the rest fall outside it in either direction. A single midpoint number without a range overstates how precise this kind of genetic estimate actually is.
Mid-parental height is a starting point based purely on genetics, but a child's actual adult height also depends heavily on nutrition during childhood and adolescence, overall health, chronic illness, hormonal factors, and simple individual growth variation — siblings with identical parents regularly land at different points within (or outside) the predicted range.
This tool is meant for general curiosity and rough planning, not medical assessment. A pediatrician tracking a child's height and growth velocity on a proper growth chart over time — factoring in growth percentiles, bone age, and pubertal timing — gives a far more accurate and individualized prediction than any formula based on parent height alone.
Height calculator questions
How the mid-parental height prediction method works, and its limits.
How do you calculate a child's predicted adult height from parents' height?
Using the mid-parental height method: for boys, (father's height + mother's height + 13) ÷ 2 in centimeters; for girls, (father's height + mother's height − 13) ÷ 2. This gives a midpoint genetic estimate of adult height.
Why is 13cm added for boys and subtracted for girls?
The 13cm adjustment reflects the average height difference between adult men and women observed in population studies, which lets the same pair of parent heights produce a sensible estimate for either a son or a daughter.
How accurate is the mid-parental height prediction method?
It's a reasonable genetic estimate, not a guarantee. The typical range is about plus or minus 8.5cm around the midpoint, meaning roughly 68% of children with those parent heights land within that range as adults — the rest fall outside it.
What other factors affect a child's final adult height besides parents' height?
Nutrition during childhood and adolescence, overall health and chronic illness, hormonal factors, and individual growth variation all play a role — which is why siblings with the same parents can end up at different heights.
Can this height calculator replace a pediatrician's growth chart assessment?
No. This is a rough genetic estimate for general curiosity. A pediatrician tracking growth percentiles, bone age, and pubertal timing on a proper growth chart provides a far more accurate, individualized prediction.
Can I use feet and inches instead of centimeters?
Yes — toggle to Imperial units and enter each parent's height in feet and inches. The calculator converts internally to centimeters for the formula and displays the result back in your chosen units.