How accurate is mid-parental height?
Rough guide—about two-thirds of kids end within the ±8.5 cm window.
Child Height Predictor
Estimate a child's adult height from both parents using the classic mid-parental height method.
Parent heights and child sex
Enter biological parent heights. Result shows predicted cm and typical ±8.5 cm range.
About this calculator
How to use Child Height Predictor, plus the formulas and logic behind the results.
Tool description
Mid-parental height averages parental stature with a sex adjustment (+13 cm boys, −13 cm girls). Most kids land within ±8.5 cm of that midpoint.
How to use
- Select boy or girl.
- Enter both parents' heights in the same units.
- Calculate predicted adult height.
- Discuss growth with pediatrician if child tracks far outside the range.
Formulas & reference
Boys: (father + mother + 13) ÷ 2 cmGirls: (father + mother − 13) ÷ 2 cmTypical range: ±8.5 cm around prediction
When to ask a doctor
- Growth curve falling off percentiles
- No puberty signs by expected age (varies)
- Height far below mid-parental range for years
- Chronic illness or steroid use affecting growth
Calculation logic
Parent heights convert to cm, sex-specific mid-parental formula applied, then range displayed.
Nutrition, health conditions, and puberty timing cause wide variation. Not a guarantee of final height.
Child Height Predictor FAQ
Common questions about this calculator and how to use the results.
Adoptive parents?
Use biological parent heights when known; otherwise clinical growth charts matter more.
Grandparent height?
Not used in this simple formula—only both parents.
Can nutrition beat genetics?
Good nutrition helps reach genetic potential but rarely exceeds it dramatically.
Teen already taller than prediction?
Late growth spurts happen; pediatricians plot bone age for clarity.
Cm or feet?
Either—pick one system for both parents.