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Child height predictor
Enter both parents' heights for the mid-parental height doctors use: a target adult height and the range most children end up in.
Formula from the Singapore Medical Journal (2016). Read on 5 Nov 2026.
Predicted adult height
How it is worked out
For a boy, add 13 cm to the mother's height and average it with the father's. For a girl, take 13 cm off the father's height and average it with the mother's. The Singapore Medical Journal says 8.5 cm either side of that number covers the 3rd to the 97th percentile of expected adult height. The Royal Children's Hospital Melbourne uses the same numbers.
The American Academy of Pediatrics uses the same formula with a wider range of 10.2 cm either side. Either way, treat the result as a range, not a promise.
Questions parents ask
How do you predict a child's adult height?
Doctors use mid-parental height. For a boy: (father's height + mother's height + 13 cm) / 2. For a girl: (father's height + mother's height - 13 cm) / 2. The Singapore Medical Journal gives a range of 8.5 cm either side.
How accurate is it?
It gives a range rather than a number. The Singapore Medical Journal says 8.5 cm either side covers the 3rd to 97th percentile of expected adult height; the American Academy of Pediatrics uses 10.2 cm either side.
Sources
- Goh LH. Failure to thrive in babies and toddlers. Singapore Med J 2016;57(6):287-291 (read 5 Nov 2026)
- Royal Children's Hospital Melbourne: Short stature pre-referral guideline (read 5 Nov 2026)
- American Academy of Pediatrics EQIPP: Mid-parental height (read 5 Nov 2026)
