Height Calculator

Child Height Predictor

How tall will your child likely become? Enter both parents' adult heights and the child's sex for a mid-parental height estimate — always shown with its honest likely range, never as a single exact number.

Please note: these are educational estimates based on published growth references, not medical advice. If you have concerns about a child's growth, consult a pediatrician.

Predict adult height

Parents' heights in cm or ft/in, plus the child's sex. The formula needs both parents — it won't guess from half the inputs.

Child's sex
Parents' heights
Father's adult height
cm
Mother's adult height
cm

The formula

This is the classic Tanner mid-parental height formula, long used in pediatrics as a quick estimate of a child's genetic target height:

  • Boy: (father's height + mother's height + 13 cm) ÷ 2
  • Girl: (father's height + mother's height − 13 cm) ÷ 2

The ±13 cm adjustment reflects the average adult height difference between men and women. Enter heights in centimetres or feet and inches — the conversion uses the exact 1 inch = 2.54 cm definition.

How accurate is it, honestly?

The prediction estimates genetic target height — not a guaranteed outcome. Most children end up within ±8.5 cm of the predicted value (roughly ±2 standard deviations of prediction error). No method predicts a child's adult height exactly, and any site that gives you a single precise number without a range is overselling.

Beyond genes, final height is shaped by nutrition, childhood health, the timing of puberty, and ordinary genetic variation — factors no formula can fully capture. Treat the range as likely, not certain, and enjoy watching where they land.

What to explore next

Already know the child's current height? See where they stand today with the boys percentile calculator or girls percentile calculator, or plot them on the interactive boys growth chart and girls growth chart.

FAQ

Child height predictor FAQs

How does the child height predictor work?

It uses the classic mid-parental height formula: for a boy, (father's height + mother's height + 13) ÷ 2; for a girl, (father's height + mother's height − 13) ÷ 2 — all in centimetres. The 13 cm adjustment reflects the average height difference between adult men and women.

How accurate is the prediction?

It estimates genetic target height, not a guaranteed outcome. Most children end up within ±8.5 cm of the predicted value — roughly ±2 standard deviations of prediction error. No method predicts a child's adult height exactly, which is why the range is always shown as part of the answer.

What can make a child end up outside the predicted range?

Nutrition, health conditions, the timing of puberty, and plain genetic variation all shift final height. The formula captures the biggest single factor — parents' heights — but it can't account for everything, so treat the range as likely, not certain.

Does it work for adopted children or if I don't know a parent's height?

The formula needs both parents' heights to work as designed. Without them, any 'prediction' would be a guess — so this tool asks for both and won't fabricate a result from half the inputs.

Is my family's data stored?

No. The calculation runs entirely in your browser; nothing you enter is sent to a server or stored.

More height calculators

Boys Height Calculator

Quick height check for boys against CDC growth references.

Girls Height Calculator

Quick height check for girls against CDC growth references.

Baby Height Calculator

Length-for-age percentiles for babies 0–24 months (WHO).

Boys Height Percentile Calculator

Exact percentile + z-score with CDC / WHO / UK-WHO switcher.

Girls Height Percentile Calculator

Exact percentile + z-score with CDC / WHO / UK-WHO switcher.

Boys Growth Chart

Interactive CDC/WHO percentile curves — plot your own point.

Girls Growth Chart

Interactive CDC/WHO percentile curves — plot your own point.

UK Boys Height Percentile

UK-WHO chart percentiles for ages 2 weeks–4 years.

Based on published growth references

Every percentile on this site is computed from official LMS tables — the same references pediatricians use. We never estimate outside the ages each reference covers.

  • CDC (US)

    CDC 2000 Growth Charts, stature-for-age (National Center for Health Statistics)

    Official source

  • WHO

    WHO Child Growth Standards, length/height-for-age (WHO Multicentre Growth Reference Study, 2006)

    Official source

  • UK-WHO

    UK-WHO growth charts (RCPCH): ages 2 weeks-4 years follow the WHO Child Growth Standards

    Official source