OneTaskBy Tim King · Updated
Child Height Predictor
How Tall Will My Child Be?
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How the Child Height Predictor works
This child height predictor estimates how tall your child will be as an adult from the mother's and father's heights. Enter heights as 5'10" or in centimetres and it shows the predicted adult height with the range most children end up in.
How the child height predictor works
Height is mostly inherited, so the parents' heights are the best simple predictor. Doctors use the mid-parental height method, which averages the parents after adjusting for the 13 cm (5 in) average gap between men and women. The formula is boy = (mother + father + 13 cm) ÷ 2 and girl = (mother + father − 13 cm) ÷ 2. About 95% of children end up within 8.5 cm (about 3.3 in) either side of that. The optional doubling rule doubles a boy's height at 2 years or a girl's at 18 months as a cross-check.
First example. A boy whose mother is 5'5" and father is 5'10" is predicted to reach about 5'10" (178 cm), with a likely range of 5'7" to 6'1".
Second example. A girl whose mother is 165 cm and father is 180 cm is predicted to reach about 166 cm, with a range of 158 to 175 cm. If she was 84 cm at 18 months, the doubling rule gives 168 cm.
How many inches does the range cover? About 3.3 in either side of the prediction, so roughly 6.7 in from bottom to top.
Nutrition, health and the timing of puberty also matter. A doctor can give a more precise estimate from a bone age X-ray if growth is a concern.
Predicted adult height by father's height, for a mother of 160 cm or 170 cm
| Father | Boy, mother 160 cm | Boy, mother 170 cm | Girl, mother 160 cm | Girl, mother 170 cm |
|---|---|---|---|---|
| 160 cm | 167 cm | 172 cm | 154 cm | 159 cm |
| 162 cm | 168 cm | 173 cm | 155 cm | 160 cm |
| 164 cm | 169 cm | 174 cm | 156 cm | 161 cm |
| 166 cm | 170 cm | 175 cm | 157 cm | 162 cm |
| 168 cm | 171 cm | 176 cm | 158 cm | 163 cm |
| 170 cm | 172 cm | 177 cm | 159 cm | 164 cm |
| 172 cm | 173 cm | 178 cm | 160 cm | 165 cm |
| 174 cm | 174 cm | 179 cm | 161 cm | 166 cm |
| 176 cm | 175 cm | 180 cm | 162 cm | 167 cm |
| 178 cm | 176 cm | 181 cm | 163 cm | 168 cm |
| 180 cm | 177 cm | 182 cm | 164 cm | 169 cm |
| 182 cm | 178 cm | 183 cm | 165 cm | 170 cm |
| 184 cm | 179 cm | 184 cm | 166 cm | 171 cm |
| 186 cm | 180 cm | 185 cm | 167 cm | 172 cm |
| 188 cm | 181 cm | 186 cm | 168 cm | 173 cm |
| 190 cm | 182 cm | 187 cm | 169 cm | 174 cm |
| 192 cm | 183 cm | 188 cm | 170 cm | 175 cm |
| 194 cm | 184 cm | 189 cm | 171 cm | 176 cm |
| 196 cm | 185 cm | 190 cm | 172 cm | 177 cm |
| 198 cm | 186 cm | 191 cm | 173 cm | 178 cm |
| 200 cm | 187 cm | 192 cm | 174 cm | 179 cm |
FAQ
How accurate is the mid-parental height method?
About 95% of children end up within 8.5 cm (3.3 in) of their predicted height. It works best when both parents' heights are measured rather than remembered, and when the child is healthy and well fed.
What is the doubling rule?
Many children reach about half their adult height at around 2 years old for boys and 18 months for girls, so doubling the height then gives a rough prediction. It is a useful second opinion only.
Can a child be taller than both parents?
Yes. Height comes from many genes, so children can end up taller or shorter than either parent. Better nutrition and health over generations also mean children are often a little taller than parents.
When do children stop growing?
Girls usually stop growing at around 14 to 16, about two years after their first period. Boys usually stop at around 16 to 18, though some keep growing slowly into their early twenties.
When should I worry about my child's height?
See a doctor if your child is far outside the predicted range, crosses down through centile lines on their growth chart, or grows much more slowly than friends of the same age over a year or more.
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