Height calculator
A child’s likely adult height from the parents’ heights.
About this calculator
How tall will my child be? This height calculator predicts a child's likely adult height from the heights of both parents.
It uses the mid-parental method that doctors use to check whether a child is growing as expected.
How it works
The mid-parental method averages the parents’ heights, then adds 6.5 cm (2.5 in) for a boy or takes off 6.5 cm for a girl. That is the same as (mother + father ± 13 cm) ÷ 2.
Last reviewed:
Worked example
- Units: Feet and pounds
- Child: Girl
- Mother’s height: 5 ft 5 in
- Father’s height: 5 ft 10 in
Likely adult height: 5 ft 4.9 in (the mid-parental target)
Common questions
How accurate is a height prediction?
Most children end up within about 8.5 cm (3.3 in) of the mid-parental target. Diet, health and genes from grandparents all play a part.
When do children stop growing?
Girls usually stop growing a year or two after their first period, around 14 to 16. Boys usually stop between about 16 and 18.
Is there a more accurate method?
Doctors can estimate from a hand X-ray that shows bone age, combined with the child's current height. Ask your doctor if you're worried.
The story behind it
Where the idea came from: The British growth expert James Tanner popularised the mid-parental height method in the 1970s.
Tanner studied thousands of children to build the growth charts doctors still use. Comparing a child's growth with their parents' heights helps spot children who may need a check-up.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, not medical advice.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
Meet the founder