Child Height Calculator
Predict a child’s adult height from the parents’ heights using the mid-parental method, with a likely range, in metric or imperial. Just for fun, in your browser.
Predicted adult height
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Show the math
The mid-parental method averages the parents and adjusts for sex:
height = (mother + father) ÷ 2 ± 6.5 cm
Add 6.5 cm (about 2.5 in) for a boy or subtract it for a girl. The ±8.5 cm band covers roughly the middle 95% of outcomes, this is a fun estimate, not a medical prediction. All math runs locally in your browser.
What this does
A child height calculator estimates how tall a child is likely to be as an adult from the heights of their two biological parents, using the well-known mid-parental ("Tanner") method. It is a rough guide for curiosity, not a medical prediction.
How to use it
- Choose the child’s sex.
- Enter the mother’s and father’s heights.
- Switch between metric and imperial if needed.
- Read the predicted adult height and likely range.
How it works
The two parents’ heights are averaged, then 6.5 cm (about 2.5 in) is added for a boy or subtracted for a girl. The likely range of ±8.5 cm covers roughly the middle 95% of outcomes.
height = (mother + father) ÷ 2 ± 6.5 cm
Understanding your result
The headline figure is a midpoint, not a guarantee — real adult height also depends on nutrition, health, and chance, so treat the ±8.5 cm band as the realistic spread. Most children land somewhere inside it.
Example
For a boy with a 165 cm mother and 180 cm father, the prediction is about 179 cm (roughly 170–188 cm).
Sources & methodology
Last updated .
Frequently asked questions
How accurate is this prediction?
The mid-parental method is a recognised rough estimate. Most children end up within about 8.5 cm of the predicted height, but nutrition, health, and genetics beyond the parents all play a part.
Does it work for adopted children?
No — it relies on the biological parents’ heights, so it is not meaningful when those are unknown or unrelated to the child.
Is anything stored?
No. Everything is calculated locally in your browser.
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