Height is about 80% genetic, so parents’ heights are the best simple predictor. Nutrition, health and the timing of puberty affect where in the target range a child ends up. Bone-age X-rays give more precise predictions.
How to use the Child Height Predictor
- Sex
- Father’s height
- Mother’s height
- Child’s height at 2 years (boys) or 18 months (girls) – optional
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter both parents’ heights and the child’s sex, and optionally the child’s height at 2 years (boys) or 18 months (girls).
Inputs explained
| Field | What to enter |
|---|---|
| Sex | Choose one: Male, Female |
| Father’s height | Units: cm, in, m, ft, mm |
| Mother’s height | Units: cm, in, m, ft, mm |
| Child’s height at 2 years (boys) or 18 months (girls) – optional | Units: cm, in, m, ft, mm |
What each result means
- Target range from = [Predicted adult height (mid-parental)] – 8.5
- Target range to = [Predicted adult height (mid-parental)] + 8.5
Example values
How the main result changes when Father’s height changes and everything else stays at the example values above:
| Father’s height (cm) | Predicted adult height (mid-parental) (cm) |
|---|---|
| 89 | 133.5 |
| 133.5 | 155.8 |
| 178 | 178 |
| 222.5 | 200.3 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Mid-parental height: boys = (father + mother + 13 cm) ÷ 2; girls = (father + mother − 13 cm) ÷ 2
Target range ≈ mid-parental height ± 8.5 cm
Rule of thumb: adult height ≈ 2 × height at age 2 (boys) or at 18 months (girls)
Worked example
Inputs — Sex: Male; Father's height: 178 cm; Mother's height: 165 cm; Child's height at 2 years (boys) or 18 months (girls) – optional: 0 cm.
Results — Predicted adult height (mid-parental) = 178 cm; Target range from = 169.5 cm; Target range to = 186.5 cm; Prediction from early height = 178 cm.
Key terms
- Mid-parental height
- Average of the parents' heights adjusted for sex.
Frequently asked questions
How accurate is mid-parental height?
About 95% of children end up within ±8.5 cm of it.
Can my child grow taller than predicted?
Yes – nutrition, sleep and health all play a part, and genetics is not exact.
When do children stop growing?
Usually around 14–16 for girls and 16–18 for boys.