How tall will your child be? This free height calculator predicts a child’s adult height from both parents’ heights using the mid-parental method, with a likely range around the estimate.
An estimate based on parents’ heights – genetics, nutrition and health all play a part, so actual adult height can differ. Ask a pediatrician for growth concerns.
How Height Calculator Works
This tool predicts a child’s likely adult height using the mid-parental height method, a simple statistical approach based on both parents’ heights and the child’s sex. It’s a widely used estimate, not a medical measurement, so treat the result as a starting point rather than a guarantee.
Formula: Mid-parental height = (Mother’s height + Father’s height) ÷ 2. For a boy, add 6.5 cm to that average to get the predicted adult height. For a girl, subtract 6.5 cm instead. The calculator also shows a likely range of ±8.5 cm (±3.3 in) around the predicted number to reflect natural variation between children.
- Mother’s height — the biological mother’s height, entered in cm or ft/in
- Father’s height — the biological father’s height, entered in cm or ft/in
- Child’s sex — boy or girl, since the adjustment applied to the average differs by sex
- Mid-parental height — the simple average of both parents’ heights before the ±6.5 cm sex adjustment
Example Scenarios
| Mother’s height | Father’s height | Child’s sex | Predicted adult height |
|---|---|---|---|
| 165 cm | 180 cm | Boy | 179 cm (±8.5 cm) |
| 165 cm | 180 cm | Girl | 166 cm (±8.5 cm) |
| 160 cm | 175 cm | Boy | 174 cm (±8.5 cm) |
| 170 cm | 190 cm | Girl | 173.5 cm (±8.5 cm) |
| 155 cm | 170 cm | Boy | 169 cm (±8.5 cm) |
Height Calculator FAQ
How accurate is the mid-parental height prediction method?
It’s a population-level estimate, not a precise forecast. The calculator shows a ±8.5 cm likely range around the prediction because genetics, nutrition, health, and puberty timing all influence how tall a child actually grows.Does this calculator use growth charts or bone-age X-rays?
No. It only uses the mid-parental method, which averages both parents’ heights and applies a sex-based adjustment. Clinical tools like growth-chart percentile tracking or a bone-age X-ray give a more individualized picture and should come from a pediatrician.Why does the same pair of parent heights give a different result for a boy versus a girl?
The formula adds 6.5 cm to the parents’ average for a boy and subtracts 6.5 cm for a girl, reflecting the typical adult height difference between sexes. That’s why entering identical parent heights produces a 13 cm gap between the boy and girl estimates.Can I use this if I only know one biological parent’s height?
The formula needs both biological parents’ heights to work as intended. If one is unknown or a parent isn’t biologically related to the child, the result becomes far less meaningful — a pediatrician can track growth-chart percentiles instead.What if my child’s actual growth is tracking differently from this prediction?
That’s expected sometimes, since this is only a statistical estimate. If a child’s growth curve sits noticeably above or below expected percentiles over time, or growth seems to stall, it’s worth discussing with a pediatrician rather than relying on this number alone.Does the calculator support both metric and imperial units?
Yes. You can enter both parents’ heights in centimeters or in feet and inches. Imperial entries are converted internally to centimeters (using 2.54 cm per inch) before the mid-parental formula is applied.Related Calculators
Once you have a predicted adult height, it can help to explore related growth and body metrics. Try the ideal weight calculator to see a healthy weight range for a given height, the BMI calculator to check body mass index once your child reaches adulthood, or the body frame size calculator to understand how frame size affects healthy weight ranges.