What will my child’s adult height be?
Enter the child's sex and both parents' heights. See the predicted adult height and the range most children of those parents fall in.
- Predicted adult height
- 69.6 in
The predicted adult height is 69.6 in (5 ft 9.6 in), likely between 66.2 in and 72.9 in.
- In feet and inches, or metres
- 5 ft 9.6 in
- In centimetres
- 176.7 cm
- Likely range from
- 66.2 in
- Likely range up to
- 72.9 in
Predicted adult height: 69.6 in. The predicted adult height is 69.6 in (5 ft 9.6 in), likely between 66.2 in and 72.9 in.
This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use
How to calculate
Predicts a child’s adult height from the parents’ heights with Tanner’s mid-parental method: (father + mother + 13 cm) ÷ 2 for a boy, − 13 cm for a girl, ± 8.5 cm.
Example with the default inputs (Child’s sex Boy, Father’s height 5 ft 10 in, Mother’s height 5 ft 4 in): The predicted adult height is 69.6 in (5 ft 9.6 in), likely between 66.2 in and 72.9 in.
Method: Predicted adult height = (father’s height + mother’s height + 13 cm) ÷ 2 for a boy, or − 13 cm for a girl; range ± 8.5 cm.
- Men are on average about 13 cm taller than women, so a parent’s height is moved by 13 cm to the child’s sex before averaging.
- The range of 8.5 cm either side is Tanner’s target range, about the 3rd to 97th centile for children of these parents.
- The parents are the biological parents, and the child grows in good health and nutrition.
- This is a rough guide for families, not a medical prediction. A pediatrician can use growth charts and bone age for more.
Worked examples
Each example is checked against the calculator on every build.
- Child’s sex Boy, Father’s height 5 ft 10 in, Mother’s height 5 ft 4 in gives Predicted adult height 69.6 in, Likely range from 66.2 in, Likely range up to 72.9 in.Source: Tanner et al. 1970 (mid-parental height ± 8.5 cm); hand calculation in content.mdx
- Child’s sex Girl, Father’s height 5 ft 10 in, Mother’s height 5 ft 4 in gives Predicted adult height 64.4 in, Likely range from 61.1 in, Likely range up to 67.8 in.Source: Tanner et al. 1970; hand calculation in content.mdx
- Child’s sex Girl, Father’s height 5 ft 10.9 in, Mother’s height 5 ft 5 in gives Predicted adult height 65.4 in, In centimetres 166 cm.Source: Tanner et al. 1970; hand calculation in content.mdx
- Child’s sex Boy, Father’s height 6 ft 2 in, Mother’s height 5 ft 7 in gives Predicted adult height 73.1 in, Likely range up to 76.4 in.Source: Tanner et al. 1970; hand calculation in content.mdx
How it works
Mid-parental target height (Tanner, 1970), with heights in centimetres:
- Boy: predicted adult height = (father's height + mother's height + 13) ÷ 2
- Girl: predicted adult height = (father's height + mother's height − 13) ÷ 2
The likely range is the prediction − 8.5 cm to the prediction + 8.5 cm, Tanner's target range (about the 3rd to 97th centile).
Heights in feet and inches are changed to centimetres first (1 in = 2.54 cm exactly). The prediction and its range are shown in inches to one decimal (US) or centimetres (Metric). The prediction is also shown in feet and inches (US) or in metres to 3 significant figures (Metric), and in centimetres to one decimal. For feet and inches, the height in inches is first rounded to one decimal, then split into whole feet and the inches left, so 71.98 in shows as 6 ft 0 in. Parents' heights can be 1 to 2.5 metres.
Assumptions
- The parents are the child's biological parents, and the child grows up healthy and well fed.
- 13 cm is the average difference in adult height between men and women.
- This calculator gives a rough guide for families. It is not medical advice or a diagnosis. If you are worried about a child's growth, talk to their pediatrician.
Worked examples by hand
A boy; father 5 ft 10 in, mother 5 ft 4 in. 70 in = 177.8 cm and 64 in = 162.56 cm. Prediction = (177.8 + 162.56 + 13) ÷ 2 = 353.36 ÷ 2 = 176.68 cm, which is 176.68 ÷ 2.54 = 69.56 in, or 5 ft 9.6 in. Range: 168.18 cm to 185.18 cm (66.2 in to 72.9 in).
A girl with the same parents. Prediction = (177.8 + 162.56 − 13) ÷ 2 = 163.68 cm = 64.44 in = 5 ft 4.4 in. Range: 155.18 cm to 172.18 cm.
A girl; father 180 cm, mother 165 cm. Prediction = (180 + 165 − 13) ÷ 2 = 166 cm = 65.35 in = 5 ft 5.4 in.
A boy; father 6 ft 2 in, mother 5 ft 7 in. 74 in = 187.96 cm and 67 in = 170.18 cm. Prediction = (187.96 + 170.18 + 13) ÷ 2 = 185.57 cm = 73.06 in = 6 ft 1.1 in. The top of the range is 185.57 + 8.5 = 194.07 cm.
Other questions people ask
How can I predict my child's adult height?
A common method is the mid-parental height (Tanner, 1970). Add the parents' heights, add 13 cm (5 inches) for a boy or take away 13 cm for a girl, and divide by 2. With a 5 ft 10 in father and a 5 ft 4 in mother, a boy's prediction is about 5 ft 9.6 in and a girl's about 5 ft 4.4 in.
Why add or take away 13 cm?
On average, adult men are about 13 cm (5 inches) taller than adult women. Moving one parent's height by that amount puts both parents on the same scale as the child before averaging.
How accurate is the prediction?
It is a rough guide. Tanner's target range is 8.5 cm (about 3.3 inches) either side of the prediction, about the 3rd to 97th centile, so two children of the same parents can end up quite far apart. Nutrition, health and puberty timing also matter.
Is there a more accurate method?
Methods that also use the child's own height, weight and age, or an X-ray of the hand to find bone age, can be more precise for a given child. A pediatrician can use these and the growth charts to follow how a child is growing.
Does this work for adopted children?
No. The method uses the biological parents' heights, because it is built on how height runs in families.
Can I enter heights in centimetres?
Yes. Switch each height to cm or m, or use the Metric switch. The result is shown in inches, feet and inches, and centimetres, or in centimetres and metres with the Metric switch.