Expected Height Calculator
An expected height calculator estimates how tall a child is likely to be as an adult. The free tool above takes both parents' heights, your child's age and current height, and returns a range rather than a single number. Below is how the number is worked out, what it means, and where it goes wrong.
How expected adult height is worked out
The standard method is the mid-parental (target) height: average the two parents' heights, then add 6.5 cm (2.5 in) for a boy or subtract 6.5 cm for a girl. The extra 13 cm is the average difference between men and women. Treat the result as the centre of a range about 5 cm either side, not a promise.
| Father / mother | Expected height, son | Expected height, daughter |
|---|---|---|
| 165 cm / 155 cm | 167 cm (5'6") ± 5 | 154 cm (5'1") ± 5 |
| 172 cm / 160 cm | 173 cm (5'8") ± 5 | 160 cm (5'3") ± 5 |
| 175 cm / 165 cm | 177 cm (5'10") ± 5 | 164 cm (5'5") ± 5 |
| 178 cm / 168 cm | 180 cm (5'11") ± 5 | 167 cm (5'6") ± 5 |
| 182 cm / 170 cm | 183 cm (6'0") ± 5 | 170 cm (5'7") ± 5 |
| 188 cm / 175 cm | 188 cm (6'2") ± 5 | 175 cm (5'9") ± 5 |
Want to try your own numbers in cm or feet and inches? The mid-parental height calculator has the full lookup table.
Expected height for age is a different question
Searching "expected height" can also mean "is my child's height normal for their age?" That is answered by percentiles on a CDC or WHO growth chart: a child at the 50th percentile is taller than half of children the same age and sex. A child between roughly the 5th and 95th percentile is usually within the normal range. See growth chart percentiles and the height chart by age.
Why use both numbers together
- Family target only. Ignores how your child is actually growing, so it can be off for early or late developers.
- Percentile only. Says where your child is now, not where they will finish.
- Both. A child whose percentile is far from their family target is worth watching over several measurements, not one.
Timing moves the answer. Two 13-year-olds with the same parents and the same height today can finish 10 cm apart if one has already had the growth spurt and the other has not started.
What does not change expected height
- Supplements and stretching devices. Nothing you can buy lengthens bone. Enough food and sleep help a child reach their ceiling; they do not raise it.
- One tall or short parent. Each parent counts for half, so a father who is 10 cm taller moves the target by only 5 cm.
↑ Run the free calculator — 60 seconds, result shown without an account.
Frequently asked questions
What is expected height?
Expected height usually means one of two things: the adult height you are expected to reach given your parents' heights (the target or mid-parental height), or the height that is typical for your age on a growth chart. This calculator gives the first and uses the second to sharpen it.
How do you calculate expected adult height?
Add both parents' heights, divide by two, then add 6.5 cm (2.5 in) for a boy or subtract 6.5 cm for a girl. The true result usually falls within about 8.5 cm (3.3 in) of that number for roughly 95% of people (Tanner et al., 1970).
How accurate is an expected height calculator?
It is a statistical estimate, not a measurement. Siblings with the same parents commonly differ by several centimetres. Using your child's current height and age on a growth chart narrows the range, but it never becomes a single exact number.
Is expected height the same as predicted height?
Close, but not identical. Expected height from parents is a family average. A predicted height also uses the child's own growth so far, such as percentile and how far through puberty they are, so it can differ from the family target.
What if my child's expected height and current growth disagree?
That is common and often fine. A child who is tall for their age but has an average family target may be an early developer who finishes nearer the target. A late developer can look short now and still reach it. A doctor should check a child who keeps crossing downward percentile lines.
This tool provides a statistical estimate for general information only. It is not medical advice, diagnosis or treatment. If you are concerned about your growth or your child's, speak to a paediatrician or family doctor.