Free tool · For parents
Child Height Predictor
How tall will your child be? Estimate their adult height with the mid-parental method doctors use, combined with where they sit on the WHO growth curve today.
Your child's estimate appears here — nothing you enter is collected or stored.
The mid-parental height formula
The genetic anchor behind this child height calculator is the formula pediatricians have used for decades — the mid-parental (Tanner) target height:
For a boy: (father's height + mother's height + 13 cm) ÷ 2
For a girl: (father's height + mother's height − 13 cm) ÷ 2
Most children end up within roughly 8–10 cm of their mid-parental target. This calculator goes one step further than the bare formula: it also looks at where your child sits on the WHO growth curve today — the share of adult height typically reached at their age and sex — and blends the two. A child who is currently tall or short for their age pulls the estimate accordingly, which is exactly what the formula alone misses.
The result comes with an honest range: wide for young children (many growth years and puberty timing still unknown), narrower for teenagers, and wider whenever a parent's height is missing.
What parents should actually watch
A single predicted number matters less than the pattern over time. Pediatricians track whether a child follows their own percentile curve — steady tracking on the 25th percentile is healthy; sliding from the 50th to the 10th is what warrants a conversation. If you're unsure where your child sits right now, start with our height comparison tool.
And the everyday levers are the boring ones: enough sleep for their age, regular protein and calcium, and daily movement. None of these push a child beyond their genetic range — but shortfalls during the growth years can leave part of that range unclaimed.
Height percentile calculator: what the curves actually mean
A height percentile calculator answers a different question than the prediction above — not "how tall will he end up?" but "how does his height today compare with other children his age?" If your son is on the 25th percentile, 25 out of 100 boys his age are shorter and 75 are taller. Everything from the 5th to the 95th percentile is a normal height — including the low end.
Pediatricians read the curve, not the single number. A boy tracking the 25th percentile year after year is growing exactly as expected. The pattern worth a doctor's visit is a drop across two or more percentile lines — say from the 50th to below the 25th — or a height far outside the typical range for the age. This predictor already reads where your child sits on that curve before projecting adult height, and the GoTaller app keeps the curve updated as they grow.
Child height FAQ
How does the mid-parental height formula work?
Add both parents' heights in centimeters, then add 13 cm for a boy or subtract 13 cm for a girl, and divide by two. That's the child's genetic target height — most children land within roughly 8–10 cm of it. This calculator combines that target with where the child currently sits on the WHO growth curve, which makes the estimate more personal than a plain mid-parental height calculator.
When do children have growth spurts?
After the fast growth of the toddler years, children typically grow at a steady 5–6 cm per year until puberty. The pubertal growth spurt usually arrives around ages 10–13 for girls and 12–15 for boys, and is the last big push before growth plates close.
Should I worry if my child is below average height?
Being below the 50th percentile is not a problem in itself — half of all children are, by definition, and children of shorter parents are expected to track lower curves. What matters clinically is the pattern over time: a child who drops across percentile curves, or sits far outside the typical range, is worth discussing with a pediatrician. This tool is a positioning cue, not a diagnosis.
How accurate is a child height predictor?
For younger children the honest range is wide — many years of growth and puberty timing remain unknown — and it narrows as the child gets older. That's why the result always shows a range, and widens it when a parent's height is missing. No calculator can promise a number.
Is my child's data collected or stored?
No. Everything is computed locally in your browser. Nothing you enter is collected, stored, transmitted, or used for tracking.
What does my child's height percentile mean?
It's your child's rank among children of the same age and sex: the 40th percentile means 40 out of 100 are shorter. A percentile describes today's height, while the prediction above estimates adult height — the two work together. A stable percentile, high or low, is what normal growth looks like; it only becomes a conversation for the pediatrician when the curve changes sharply.
START HERE
Height comparison
Where does your child sit on the curve today? Check their percentile first.
FOR TEENS
How tall will I be?
Is your teen asking for themselves? The self-serve version speaks their language.
IN THE APP
Track the trend
GoTaller logs measurements over time and reads the trend, not the noise — the pattern pediatricians care about.
Related reading: how accurate are height predictors? · the best height predictor for a child
The estimate is free. The follow-through is in the app.
GoTaller tracks your child's growth against the estimate and turns sleep, nutrition and posture into a simple daily routine.
Estimate only · not medical advice