Height Calculator

The most widely used quick estimate is the mid-parental height formula. Add the mother's and father's heights in inches; for a boy add 5 inches, for a girl subtract 5 inches; then divide by 2. Example: mother 5 ft 4 in (64 in) and father 5 ft 10 in (70 in) gives a boy (64 + 70 + 5) ÷ 2 = 69.5 in ≈ 5 ft 9.5 in, and a girl (64 + 70 − 5) ÷ 2 = 64.5 in ≈ 5 ft 4.5 in. It's a statistical estimate of genetic potential, not a guarantee — most children end up within about 4 inches either side of the number.

It's a rough genetic midpoint with a wide error band: most children end up within about 4 inches (10 cm) of the estimate either way, and some land outside it. Height is influenced by many genes plus childhood nutrition and health, so no simple formula can be precise. Clinicians use the mid-parental number as a screening reference alongside growth-chart tracking — a child's own percentile curve on a CDC chart, followed over time from about age 2, is generally a better everyday predictor, and pediatric endocrinologists refine estimates further with a bone-age X-ray.

Only very roughly. The folk rule — double a boy's height at age 2 (some versions use 18 months for girls) — half-works because children reach about half their adult height around age 2. But it hangs everything on a single measurement taken on a single day, carries no error range, and drifts badly for early or late bloomers. A 34-inch two-year-old doubles to 5 ft 8 in, which is plausible but not dependable. Treat it as a curiosity; the mid-parental formula plus CDC growth-chart tracking is the better estimate.

Typical patterns: girls hit their growth spurt earlier — often around ages 10–14 — and most reach adult height around 15–16, commonly about two years after their first period. Boys spurt later, often between 12 and 16, and most finish around 16–18, with some adding a little height into their late teens. Growth stops when the growth plates in the long bones fuse after puberty. Timing varies widely from child to child, and late bloomers are common and usually completely normal — a pediatrician can assess maturity with a bone-age X-ray if there's concern.

Yes. Height is polygenic — shaped by many gene variants that shuffle in every generation — so siblings with the same parents can differ by several inches. Statisticians also expect regression toward the mean: children of very tall parents tend to be somewhat shorter than their parents on average, and children of very short parents somewhat taller. That's exactly why this calculator reports a ±4 inch range rather than a single number, and why childhood nutrition and health can move the outcome within that genetic range.

Mostly by tracking, not formulas. Pediatricians plot a child's height on CDC growth charts at each visit and watch the percentile curve — after about age 2, healthy children tend to follow roughly the same curve, so where the curve leads is the working prediction. When precision matters, a pediatric endocrinologist can X-ray the hand and wrist to read bone age (skeletal maturity) and estimate remaining growth. A child who falls across percentile curves, or who is far shorter or taller than expected for the family, is worth discussing with a pediatrician.

Yes — in one direction. Chronic undernutrition or long-running illness in childhood can prevent a child from reaching their genetic height potential, which is why growth tracking is a core part of pediatric care. But the reverse doesn't hold: once a child is eating a normal, balanced diet, extra food, protein powders or supplements will not push height beyond what their genes allow. Adequate overall nutrition, sleep and general health let a child reach their potential; nothing sold in a bottle raises the ceiling.

No — once the growth plates in the long bones fuse after puberty, adult height is fixed, and no stretching routine or supplement changes it. What does vary is measurement: most people are around 1–2 cm (up to about half an inch) taller first thing in the morning than at night because spinal discs compress during the day, and posture affects apparent height. So measure at a consistent time of day, without shoes, against a wall — and be suspicious of anything that claims to add height after the teenage years.

CDC's NHANES survey — which physically measures participants rather than asking them — puts the average US adult man at about 5 ft 9 in (about 175 cm) and the average adult woman at just under 5 ft 4 in (about 161 cm). The Advanced level of this calculator plots your child's predicted height against those averages. Remember that averages are midpoints of wide distributions: a prediction an inch or two either side of average is entirely ordinary.