Child Height Predictor

Estimates a child's adult height and its likely range from the parents' heights, using the mid-parental (target height) method.

How to use

1. Choose cm or "ft and in" under "Units".
2. Choose "Boy" or "Girl" under "Child's sex".
3. Enter the father's and mother's heights. The estimate and the expected range appear at once, with a range bar.
4. Optionally tick "Also try the height-at-age-2 rule of thumb (folk rule)" and enter the height around the 2nd birthday.

How it works

• Boy = (father + mother + 13 cm) ÷ 2; girl = (father + mother − 13 cm) ÷ 2. The formula was proposed by Tanner and colleagues in 1970.
• The expected range is the estimate ± 8.5 cm, which reflects how much the heights of children of the same parents vary.
• Twice the height at age 2 is an old rule of thumb, not a tested method.
• This is a statistical estimate and the actual height can differ. If you are worried about growth, talk to a pediatrician.

Questions and answers

How tall will my child be if the father is 5 ft 10 in and the mother is 5 ft 4 in?

A boy is estimated at about 5 ft 9.6 in and a girl at about 5 ft 4.4 in, each with a range of about ± 3.3 in.

Why add or subtract 13 cm?

It is the usual difference between average adult male and female height, so both parents' heights are brought to the child's sex before averaging.

How accurate is the mid-parental height?

Children of the same parents differ in height, so read the result as a range. It can be further off when the parents' heights differ a lot or are very short or very tall.

Can I use centimetres?

Yes. Switch "Units" to cm. The calculation always uses 1 in = 2.54 cm.