At what age do boys stop growing?

There's no single universal age. Growth generally continues later and more gradually in boys than in girls, tapering off somewhere between about 16 and 19 for most, with real individual variation being normal.

What causes boys to stop growing?

Growth plates (epiphyseal plates) at the ends of long bones fuse and stop lengthening. In males, complete fusion can begin as early as age 14, and virtually all males have fused growth plates by 19.

Why do boys stop growing later than girls?

Boys typically enter puberty roughly two years later than girls on average, and the pubertal growth spurt and subsequent growth-plate fusion follow that later timeline, pushing the whole process later too.

Does CDC height data show boys' growth tapering off?

Yes, but more gradually than for girls. This site's CDC/NHANES reference shows a still-large jump from 169.0cm at 14 to 173.8cm at 15, then a much slower climb — roughly 0.6cm a year — through to 175.9cm at 19.

Can a boy still grow after 19?

It's uncommon but not impossible for a small amount of growth to continue past 19, since growth-plate fusion timing varies between individuals. By 19, virtually all males have fused growth plates, so further change is typically minimal.

Should I worry if my son's growth seems unusual?

This article describes a general population pattern, not medical advice. If you have a specific concern about a child's growth, a GP or paediatrician can assess it properly, including checking growth-plate status if needed.

When do boys stop growing?

Boys’ height growth continues later and more gradually than girls’, usually tapering off somewhere between about 16 and 19. CDC data shows a still-substantial jump between 14 and 15, then a much slower climb into the late teens. The underlying cause is growth-plate fusion, and this is a general pattern, not medical advice for a specific child.

CDC male height by age: growth tapering, not stopping sharply

Age	Median height (CDC/NHANES)
13	163.9cm
14	169.0cm
15	173.8cm
16	174.5cm
17	174.8cm
18	175.3cm
19	175.9cm
20 (adult aggregate)	175.1cm

Unlike the sharper female plateau, the jump from 14 to 15 here is large — about 4.8cm — showing the growth spurt is still in full swing at that age. From 16 onward the climb slows markedly, averaging roughly 0.6cm a year through to 19, and the adult (20+) aggregate of 175.1cm sits close to the age-19 figure. Boys’ growth doesn’t stop sharply at one age in this data; it tapers off gradually instead.

See where 174.5cm at age 17 — close to this table’s own age-16/17 figures — lands on the wider CDC reference curve.

Percentile

49th

At 174.5 cm and age 17, you are taller than approximately 49% of the CDC reference population for your sex.

z-score -0.03

See this height on the comparison board

Why growth stops: growth plates fusing

The biological cause is the same one behind girls’ growth stopping, just on a later timeline. Long bones lengthen from growth plates (epiphyseal plates) near each end. While these plates are open, bone can keep lengthening; once they fuse into solid bone, that particular bone stops growing longer for good.

In males, complete growth-plate fusion can begin as early as age 14 in some bones. Virtually all males have fused growth plates by age 19, broadly matching where the CDC median curve above has essentially flattened out.

Puberty timing explains why this runs later than girls. Boys commonly enter puberty around two years behind girls on average, so the pubertal growth spurt, and the growth-plate fusion that follows it, both land later on the calendar too. The mechanism is identical; the schedule is shifted.

Height isn’t the only thing that changes around this time, either. Puberty brings a cluster of other physical changes alongside the growth spurt, and growth-plate fusion is simply the skeletal event that eventually brings height growth specifically to a close, distinct from those other changes.

Why there’s a range, not one exact age

Individual variation is normal here too. Two boys can enter puberty at noticeably different ages, and growth-plate fusion timing tracks puberty rather than a fixed calendar age. That’s why “when do boys stop growing” doesn’t have one universal answer.

The honest answer is a range: most boys’ height has largely tapered off somewhere between about 16 and 19, with earlier puberty generally meaning an earlier finish, and later puberty meaning growth continues a little further. Neither pattern is a problem on its own; it’s simply how variation in pubertal timing plays out.

Genetics, nutrition and general health during childhood all influence the timing and extent of the pubertal growth spurt as well, which is part of why no single age applies to everyone equally, and part of why boys’ overall spread of final adult heights is wider than one number can capture.

Calendar age versus bone age

Growth-plate fusion tracks a body’s biological development, sometimes called bone age, rather than calendar age alone. Two boys born on the same day can have growth plates at different stages of fusion, because puberty and skeletal maturity don’t run on a fixed calendar.

This is why a clinician assessing a specific child’s growth would typically look at more than just age in years. Bone age can be read from an X-ray by a specialist, which is a clinical assessment this article can’t replace, only describe in general terms.

It’s also part of why boys’ final adult heights vary more widely around the median than a single age-by-age table can capture. A late-maturing boy can keep gaining height well after an early-maturing peer has essentially finished.

How this compares to girls

Growth-plate fusion follows the same basic biology in girls, but on an earlier timeline, because girls typically enter puberty around two years ahead of boys on average. The result is a growth curve that plateaus more sharply and finishes earlier, rather than the more gradual taper visible in the male data above.

See the companion article on when girls stop growing for the equivalent CDC data and age range.

What the CDC data does and doesn’t show

The table above uses this site’s CDC/NHANES reference table, the same data behind the percentile calculator. It reports median height at each single year of age from the underlying NHANES sample, plus one aggregate figure for all adults 20 and over.

It’s a snapshot of a US population sample, not a growth curve tracking the same individuals over time. The CDC/NHANES adult figures used across this site are also approximated from published percentile columns rather than the original LMS growth-chart constants — a documented approximation, not an exact clinical growth chart. Even with that caveat, the pattern of continued, gradually slowing growth through the late teens is clear and consistent in the data.

A general pattern, not medical advice

Everything on this page describes population-level patterns, not a diagnosis or a guarantee for any individual child. Growth-plate fusion timing genuinely varies between individuals, and some boys will continue growing slightly later than 19, or finish somewhat earlier than 16.

If you have a specific concern about a child’s growth — whether it seems too fast, too slow, or has stopped unusually early — a GP or paediatrician is the right person to assess it. They can examine growth history properly and, where appropriate, check growth-plate status directly, which no online table or calculator can do.

A boy who seems to be growing later than friends of the same age isn’t necessarily unusual. Puberty timing varies widely within the normal range, and a later start often simply means a later, sometimes longer, growth spurt rather than a smaller eventual height.

Method and sources

The age-by-age median heights in the table come directly from this site’s CDC/NHANES stature-for-age reference (Fryar et al., 2016), the same table used by the percentile calculator above. The growth-plate fusion timing and puberty-linked timing description are drawn from Wikipedia’s “Epiphyseal plate” article and the PMC review “Pubertal growth and epiphyseal fusion,” both cited below, which themselves draw on peer-reviewed fusion-timing research.

Try the percentile calculator to check a specific age and height against the CDC reference, see also when do girls stop growing for the equivalent pattern in females, or open the comparison board to see any two heights side by side.