How to use this calculator
- Enter or choose child.
- Enter or choose heights in.
- Enter or choose father’s height.
- Enter or choose mother’s height.
- The target adult height updates as you type. Use Copy result or Share to keep it.
Method
Boy: (Father + Mother + 13 cm) ÷ 2; Girl: (Father + Mother − 13 cm) ÷ 2; Range: target ± 8.5 cm
- 13 cm (5.12 in)
- average difference between adult male and female height
- 8.5 cm
- about two standard deviations either side of the target
Worked example
- Add the parents’ heights: 180 + 165 = 345 cm.
- For a boy add 13 cm and halve: (345 + 13) ÷ 2 = 179 cm.
- Range: 179 − 8.5 = 170.5 cm to 179 + 8.5 = 187.5 cm.
A boy whose parents are 180 cm and 165 cm has a target adult height of about 179 cm (5 ft 10.5 in), most likely between 170.5 and 187.5 cm.
What the result means
The target is where a child’s growth would be expected to head given the parents’ heights. Many children end up a few centimetres from it, and some outside the range. A child whose growth is moving well away from their target range is worth discussing with a doctor, who will use growth charts and other measurements.
Assumptions and limits
- Mid-parental (target) height method of Tanner, Goldstein and Whitehouse (1970), as presented by the MSD Manual.
- Both parents’ adult heights are measured, not estimated.
- The child’s growth is not affected by illness, nutrition problems or medication.
- It does not use the child’s own height, age or bone age, so it cannot detect early or late growth.
- It works less well when parents’ heights are very different or unusually tall or short.
Questions
How accurate is it?
The ±8.5 cm range covers roughly 95% of children whose growth is typical. Methods that also use the child’s current height and bone age, done in a clinic, are more precise.
Can I use inches?
Yes. Choose inches; the method is the same with 5.12 in in place of 13 cm.
Sources
Please note: This is a general screening estimate for adults, not medical advice or a diagnosis. Talk to a qualified health professional about your health.