How to use
- Enter the father's and mother's heights in feet and inches or in centimetres.
- Choose the child's sex. Optionally enter the child's age and current height.
- Read the predicted adult height, the likely range and each method's result.
Options explained
- Mid-parental height
- Boys (father + mother + 13 cm) ÷ 2; girls (father + mother − 13 cm) ÷ 2. About 95% of children end up within 8.5 cm of this.
- Current height percentile
- The child's height is placed on the CDC growth chart (WHO on non-English pages) and followed along the same percentile line to age 20. It works best from about 4 years until puberty starts.
- Combined estimate
- When the current height is entered, the main result is the average of the mid-parental and percentile estimates, which is usually closer than either alone.
Examples
| Father | Mother | Boy (mid-parental) | Girl (mid-parental) |
|---|---|---|---|
| 170 cm | 158 cm | 170.5 cm | 157.5 cm |
| 175 cm | 162 cm | 175.0 cm | 162.0 cm |
| 180 cm | 165 cm | 179.0 cm | 166.0 cm |
Frequently asked questions
How accurate is this?
Genes explain roughly 70% of adult height, so any formula gives a range rather than a number. Nutrition, sleep, health and the timing of puberty all play a part.
Is there a more accurate method?
Adding the child's current height (the percentile method here) helps, especially between 4 years and puberty. Clinical methods such as Bayley–Pinneau also use bone age from a hand X-ray and need a doctor's assessment.
Can I enter heights in feet and inches?
Yes. Switch the units to feet and inches; results are shown in feet and inches with centimetres underneath.
Why can the child's current percentile differ from the genetic target?
Children who start puberty early are temporarily taller for their age, and late bloomers temporarily shorter. A big gap between the two estimates before puberty is worth mentioning at the next check-up.
Privacy
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