Height Calculator guide
Height Calculator: Predict a Child's Adult Height
Use our height calculator to estimate how tall a child will be as an adult from their parents' heights, or convert heights between cm and feet.
By the AllCalculator editorial teamUpdated 16 October 20261 min read
How tall will my child be? Genes play the biggest part, so parents' heights give a good estimate. Our Height Calculator uses the method doctors use, and also converts heights between centimetres and feet.
How to use the calculator (Height Calculator)
To predict a child's adult height:
- Choose boy or girl.
- Enter the mother's and father's heights, in centimetres or feet and inches.
Or choose convert a height to switch between cm and feet and inches.
The mid-parental height method
- Boys: (mother's height + father's height + 13cm) ÷ 2
- Girls: (mother's height + father's height − 13cm) ÷ 2
The 13cm allows for the average height difference between men and women. About 95% of children end up within 8.5cm of this target.
A worked example
With the calculator's default settings, a girl whose mother is 165cm and father is 178cm has a predicted adult height of (165 + 178 − 13) ÷ 2 = 165cm (5ft 5in), likely between 157cm and 174cm.
Frequently asked questions
How accurate is it?
It's a rough guide. Nutrition, health, sleep and when puberty starts all play a part.
Is there a more accurate method?
Doctors can estimate it more precisely using an X-ray of the hand to see how much growing is left.
Should I be worried about my child's height?
Your health visitor or GP tracks growth on the UK-WHO charts in your child's red book. Ask them if you're worried.
To check an adult's weight for their height, use our Healthy Weight Calculator.
Sources and further reading
Links open official and independent websites in a new tab.
This guide is general information to help you understand your options. It isn't financial, tax, legal or building advice and doesn't take your personal circumstances into account. Figures were checked when the guide was last updated and can change, so confirm anything important with GOV.UK, HMRC, a regulated adviser or a qualified tradesperson.