Height Calculator (Child Height Predictor)
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About Height Prediction
“How tall will my kid be?” has three grades of answer: the parent-based formula here (instant, ballpark), percentile-tracking on growth charts (a child who rides the 75th percentile usually finishes near it), and bone-age X-ray assessment (the clinical gold standard when it medically matters). This tool delivers the first — honestly labeled.
Enter both parents' heights and the child's sex for the estimate and its likely range. Siblings share the same mid-parental number yet routinely land several centimeters apart — that's the ±8.5 cm band doing exactly what it says.
Tracking where a child stands against peers right now? That's the Height Percentile Calculator
The Mid-Parental Formula
One average, one sex offset:
Boy: (mother + father) ÷ 2 + 6.5 cm Girl: (mother + father) ÷ 2 − 6.5 cm Likely range: estimate ± 8.5 cm (± 3.3 in)
Worked example: mother 165 cm, father 180 cm → mid-parental 172.5. A son estimates 179 cm (5′10″), range 171–188; a daughter 166 cm (5′5″), range 158–174. The 13 cm gap between the two estimates is the average adult sex difference — the formula's entire adjustment.
Example Predictions
The formula across common parent combinations (computed by this calculator):
| Mother | Father | Son (est.) | Daughter (est.) |
|---|---|---|---|
| 155 cm (5′1″) | 170 cm (5′7″) | 169 cm (5′7″) | 156 cm (5′1″) |
| 160 cm (5′3″) | 175 cm (5′9″) | 174 cm (5′9″) | 161 cm (5′3″) |
| 165 cm (5′5″) | 180 cm (5′11″) | 179 cm (5′10″) | 166 cm (5′5″) |
| 170 cm (5′7″) | 185 cm (6′1″) | 184 cm (6′0″) | 171 cm (5′7″) |
| 175 cm (5′9″) | 190 cm (6′3″) | 189 cm (6′2″) | 176 cm (5′9″) |
Every cell carries the same silent ±8.5 cm — reading the table without the range is how formulas get oversold.
What Moves the Outcome
Within the genetic range, the levers are unglamorous: adequate nutrition (the reason average heights climbed a full head over the last century in many countries), managed chronic conditions, and sleep — growth hormone pulses strongest in deep sleep. Puberty timing shifts the schedule more than the destination: early bloomers spurt sooner and stop sooner; late bloomers keep growing after peers plateau.
When prediction turns clinical: a child crossing percentile lines downward on the growth chart, sitting far below the parental range, or showing very early/late puberty warrants a pediatric conversation — bone-age assessment separates 'late bloomer' from conditions worth treating. For the record, the other folk formula (doubling height at age 2, or 18 months for girls) is a rougher cousin of the same idea — the growth chart beats both.
Frequently Asked Questions
How tall will my child be?
Average the parents' heights and adjust for sex: +6.5 cm for boys, −6.5 for girls. Mother 165/father 180 predicts a 179 cm son or 166 cm daughter — within ±8.5 cm for most children. Growth-chart tracking with a pediatrician refines it over time.
How accurate is the mid-parental method?
Honest ballpark: most children land within ±8.5 cm (±3.3 in) — a wide band, because siblings share parents yet differ. It's a starting estimate; percentile tracking and (when indicated) bone-age assessment are the upgrades.
Does doubling a child's height at age 2 work?
As folklore with a kernel: 2-year-old height correlates with adult height (girls' version uses 18 months), but it inherits every measurement quirk of a squirming toddler. The mid-parental formula plus growth-chart percentile is the steadier pair.
Which parent determines a child's height?
Both — height is polygenic across hundreds of variants inherited from each parent, which is why the formula averages them. No 'height comes from the father' shortcut survives the data; the mid-parental average IS the genetic summary.
Can nutrition or exercise make a child taller?
Adequate nutrition lets a child REACH their genetic range — deficiency can cost real centimeters — but surplus food or supplements don't add beyond it. Exercise is excellent for development and neutral for adult height; only the deficiency direction moves the needle.
When should I worry about my child's growth?
Signals worth a pediatrician visit: dropping across percentile lines, height far below the parental target range, growth under ~4 cm/year in mid-childhood, or puberty notably early/late. Most cases are constitutional timing; the visit sorts which.
Methodology. This calculator uses formulas and health categories recognized by the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC). It is reviewed and maintained by the Vast Calculators editorial team.
Last updated · July 11, 2026
Disclaimer. This tool provides estimates for general informational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider before making decisions about your health.