Child Height Predictor & Genetic Target Height Calculator
How tall will your child be as an adult? Enter both parents' heights to calculate the pediatric mid-parental target height and expected adult height range using the Tanner and AAP formulas.
Enter parents' heights
Select your child's sex and enter the mother's and father's height in centimeters (cm). Optionally add your child's height at age 2 (24 months) to compare the second estimation method.
If known, enter your child's height at age 2 (in cm) to also see the AAP's 'double the 2-year height' estimate.
Genetic Target Height & Expected Range
Girl formula: (Mother + Father − 13 cm) ÷ 2- Genetic target height (midpoint)
- 164.5 cm
- Tanner target range (±8.5 cm)
- 156 – 173 cm
- Mid-parental average
- 171 cm
Expected central adult height based on the Tanner mid-parental formula
95% genetic corridor for children of the same parents
Raw average of mother's and father's height before the ±13 cm sex adjustment
This tool is for educational guidance, not medical diagnosis. Even full siblings often differ in adult height by several centimeters due to genetic recombination, nutrition, sleep, and puberty timing.
5 Key Factors That Shape Adult Height
Genetics (60–80%) & sibling variation
Inherited genes from both parents are the primary driver of height, but each child receives a unique combination. Full siblings raised in the same home can naturally differ by 8–10 cm in adult height.
Nutrition, deep sleep & physical activity
Balanced protein, calcium, vitamin D, and regular active play help children reach the upper end of their genetic potential. Growth hormone is released primarily during deep nighttime sleep.
Growth curve trajectory over single measurements
Pediatricians focus less on a single height reading and more on whether your child follows their own percentile curve steadily and whether that curve aligns with their mid-parental target range.
Puberty timing & growth spurts
Girls typically hit their pubertal growth spurt about 2 years earlier than boys. Early bloomers may be taller in childhood but stop growing sooner, while late bloomers often grow for longer.
When to consult a pediatrician
Talk to your pediatrician if your child crosses two major percentile lines downward, tracks well below their genetic target corridor, or shows signs of puberty before age 8 in girls or age 9 in boys.
The mid-parental height formula and target corridors are based on the American Academy of Pediatrics (AAP / HealthyChildren) and Tanner et al. (1970) pediatric growth standards.
Frequently Asked Questions About Child Height Prediction
How is a child's adult height calculated from parents' heights?
Pediatricians use the mid-parental height formula introduced by J. M. Tanner and colleagues in 1970. For boys, add the mother's and father's heights in centimeters, add 13 cm, and divide by 2. For girls, add both parents' heights, subtract 13 cm, and divide by 2. The 13 cm (about 5 inches) reflects the average adult height difference between men and women.
How accurate is the 'double the height at age 2' method?
The American Academy of Pediatrics (AAP) notes that doubling a child's height at age 2 (or 18 months for some girls, since girls mature faster) is a popular rule of thumb. While fun for a quick ballpark, clinical growth monitoring relies on the parent-based Tanner target corridor.
Why does the calculator show a ±8.5 cm range instead of one exact number?
No formula can predict exact adult height to the centimeter. In Tanner's data, 95% of children end up within ±8.5 cm (about ±10 cm per AAP) of their mid-parental target height. Every height inside this corridor is considered completely normal for that family.
What if my child's current percentile is outside their genetic target range?
If a child's height percentile tracks significantly below their mid-parental corridor or their annual growth velocity slows down, consult your pediatrician. They can evaluate nutrition, thyroid or growth hormone markers, and bone age (via a simple left-wrist X-ray) to assess remaining growth potential.
