How Tall Will Your Child Be as an Adult?
It is the question every parent asks at some point — and pediatricians have a science-backed answer: the mid-parental height method. By averaging both parents’ heights and adjusting for the child’s gender, it predicts adult height to within about ±8.5 cm for most children.
This free calculator runs that method instantly in centimeters or feet & inches, shows the full working, and gives the likely range — not just a single number. No signup, everything runs privately in your browser.
Mid-parental height method
Please enter both parents’ heights greater than zero.
Predicted adult height
A population estimate, not a medical prediction. Genetics sets the range, but nutrition, sleep, exercise and health move a child within it. About two-thirds of children land within ±8.5 cm of the mid-parental value. If you are concerned about a child’s growth, a pediatrician — not a calculator — is the right next step.
How to Use the Height Calculator
- Enter both parents’ heights — in centimeters, or feet and inches. Use barefoot morning heights for best accuracy.
- Select the child’s gender and press Predict. Boys get +13 cm (the average adult male–female gap); girls get −13 cm.
- Read the range. The headline is the midpoint; the likely range spans ±8.5 cm around it, where roughly two-thirds of children land.
The Formula: Mid-Parental Height
Girl: (father + mother − 13 cm) ÷ 2
Likely range: prediction ± 8.5 cm
Worked example: father 180 cm, mother 160 cm. Boy: (180 + 160 + 13) ÷ 2 = 176.5 cm (5′9.5″), range 168–185 cm. Girl: (180 + 160 − 13) ÷ 2 = 163.5 cm (5′4.4″), range 155–172 cm.
What Moves a Child Within the Range?
| Factor | Effect |
|---|---|
| Nutrition | Adequate protein, calcium, vitamin D support full genetic potential |
| Sleep | Growth hormone releases mainly during deep sleep |
| Exercise | Active play supports bone health and posture |
| Health | Chronic illness or hormonal conditions can shift growth |
Who Uses Height Prediction
- Curious parents wondering about the teenage years ahead.
- Pediatricians checking whether a child’s growth tracks their genetic target.
- Coaches getting a rough sense of athletes’ future frames (with all the usual caveats).
Height Conversion Chart (cm to Feet and Inches)
Predictions come out in centimeters for much of the world and in feet and inches elsewhere. These are the common adult heights, converted at exactly 2.54 cm per inch and rounded to the nearest inch:
| Centimeters | Feet / inches | Centimeters | Feet / inches |
|---|---|---|---|
| 150 cm | 4′11″ | 175 cm | 5′9″ |
| 155 cm | 5′1″ | 180 cm | 5′11″ |
| 160 cm | 5′3″ | 185 cm | 6′1″ |
| 165 cm | 5′5″ | 190 cm | 6′3″ |
| 170 cm | 5′7″ | 195 cm | 6′5″ |
Other Ways to Estimate a Child’s Adult Height
Mid-parental height is the simplest method, not the only one. The old doubling rule says a boy’s height at age 2 (or a girl’s at 18 months) is roughly half his adult height — double it for a quick estimate. It needs no parent heights at all, but it is rougher than the mid-parental method. The Khamis-Roche method adds the child’s own current height and weight to the parents’ heights and is generally the most accurate formula approach for children aged 4 and up. When a clinician has real concerns, a bone-age X-ray of the hand and wrist — comparing bone development against age standards — is the reference method both formulas defer to.
Frequently Asked Questions
How accurate is the mid-parental height method?
It is the best simple estimator available: about two-thirds of children end up within ±8.5 cm of the prediction. It is a population estimate, not a guarantee for any individual child.
At what age can you predict adult height?
The mid-parental method works at any age since it only needs the parents’ heights. Pediatricians refine it after age 2–3 using the child’s own growth curve and, in teens, bone-age X-rays.
Do boys always end up taller than predicted and girls shorter?
No — the ±13 cm adjustment already accounts for the average sex difference. Individual children scatter around their own prediction regardless of gender.
Can nutrition make my child taller than predicted?
Good nutrition helps a child reach the top of their genetic range; it cannot push them past it. Chronic undernutrition, on the other hand, can leave a child well below prediction.
Why 13 cm and 8.5 cm?
13 cm is the average adult height gap between men and women in the reference populations; 8.5 cm is roughly one standard deviation of the prediction error, covering about two-thirds of children.
Should I worry if my child is tracking below the range?
A single calculator result is not a diagnosis. If a child’s growth curve is flattening or far from their genetic target, a pediatrician — not a website — is the right next step.
How tall will my child be if I double their height at age 2?
The doubling rule takes a boy’s height at age 2 (a girl’s at 18 months) as roughly half of adult height, so doubling gives a ballpark adult height. It is a fun first guess but less reliable than the mid-parental method above, because it ignores both parents’ heights entirely.
What is the Khamis-Roche method?
A height-prediction method that uses the child’s current height and weight plus both parents’ heights, developed for children from about age 4 into the teens. Because it includes the child’s own growth so far, it is usually more accurate than mid-parental height alone, though it still gives a range, not a certainty.
Do growth charts predict adult height?
Not directly. Growth charts track which percentile a child is following over time — a child holding steady near the 40th percentile is usually growing normally for them. Pediatricians combine that trajectory with the mid-parental target range; the chart shows the path, the formula estimates the destination.
Final Thoughts
Height prediction is science-backed fun — useful for curiosity and for pediatricians tracking growth, but never a verdict. Feed them well, let them sleep, keep them active, and whatever the number says, they will land where their genes intended.
Try our BMI calculator for healthy weight ranges.