Most boys still have a few centimeters of height left to gain after turning 16, though the amount varies widely depending on how far along puberty has progressed. A boy who hit his growth spurt early might be nearly done growing by 16, while a late bloomer could still have several inches ahead of him. Growth plate imaging studies show that the major long bones in males are not fully fused until around age 19 on average, and some sites do not reach complete closure until the early twenties. The interplay of genetics, hormones, nutrition, and pubertal timing makes this one of those questions where “it depends” is genuinely the most honest starting point.
What Growth Plates Reveal About Remaining Height
Your height comes from the lengthening of long bones in your legs and spine, and that lengthening depends on growth plates, the cartilage zones near the ends of bones that gradually harden into solid bone as you mature. Once a growth plate is fully fused, that bone can no longer get longer. The timing of this fusion is the single biggest factor in how much a boy grows after 16.
An MRI-based study of adolescents and young adults found that by age 19, complete growth plate fusion had occurred in roughly 90 to 98 percent of males across the major long-bone sites, including the femur, tibia, and radius.1PubMed Central. A cross-sectional magnetic resonance imaging study of factors influencing growth plate closure in adolescents and young adults For comparison, girls reached a similar degree of fusion about two years earlier, around age 17. A separate study focused on knee-joint epiphyses found that complete union in males began appearing at 17 to 18, but 100 percent of males did not show complete fusion at the knee until the 21-to-22 age group.2PubMed Central. Bone Age Determination of Epiphyseal Fusion at Knee Joint and Its Correlation with Chronological Age That means a small number of boys retain open growth plates at the knee well into their early twenties, though the amount of growth coming from those last-to-close plates is usually minimal.
In practical terms, most boys gain the bulk of their remaining height between 16 and 18. After 18, any additional growth tends to be slight and comes mainly from the spine rather than the legs.
Why Boys Keep Growing Longer Than Girls
The reason boys get a longer growth window than girls comes down to estrogen, which might seem counterintuitive. People tend to think of testosterone as the growth hormone in males, and testosterone does matter for building muscle and widening bones. But the signal that actually tells growth plates to close is estrogen. Boys produce estrogen too, just in smaller quantities, and the slower buildup of estrogen during male puberty is precisely why their growth plates stay open longer.
Research on the male skeleton has established that estrogen is the primary driver of both the pubertal growth acceleration and the eventual closure of the growth plates.3PubMed Central. The endocrine role of estrogens on human male skeleton Testosterone plays a complementary role, contributing to bone width and density, but the timing of when a boy stops getting taller is controlled more by how quickly estrogen levels rise than by testosterone itself.4PubMed. Sex steroids and the male skeleton: a tale of two hormones Both the androgen receptor and the estrogen receptor are needed for a boy to reach his full genetic height potential, but the estrogen receptor is the one that flips the switch on growth plate fusion.
This has a direct practical consequence: boys who enter puberty later have lower estrogen levels at 16, so their growth plates remain more open and they have more growing left to do. Boys who matured early have had estrogen circulating longer, and their plates close sooner.
Early Bloomers Versus Late Bloomers
Pubertal timing is the single most useful predictor of how much height a 16-year-old boy has left. Research tracking boys through adolescence has consistently found that those who hit their peak growth spurt later also had a greater magnitude of growth at that peak.5PubMed. Timing and magnitude of peak height velocity and peak tissue velocities for early, average, and late maturing boys and girls An early maturer might reach peak height velocity at 12 or 13 and be essentially done by 16. A late maturer might not hit that peak until 14 or 15, meaning he’s still in the tail end of his growth spurt at 16 and could comfortably add several more inches over the following years.
Constitutional delay of growth and puberty is the clinical term for what people casually call being a “late bloomer.” It’s not a disease. It simply means puberty started later than average, and everything that follows, including the growth spurt and eventual plate closure, is shifted later as well. Boys with this pattern are often the shortest in their class at 14 or 15 but can continue growing into their late teens or even early twenties. One long-term follow-up of boys with untreated constitutional delay found that most eventually reached a normal adult height, though about half of the participants felt their growth delay had affected them socially or at school.6PubMed Central. Final height in boys with untreated constitutional delay in growth and puberty A broader review noted that delayed puberty can carry psychological and even metabolic consequences into adulthood, which is worth knowing if you’re currently going through it and feeling frustrated.7PubMed Central. Adult Consequences of Self-Limited Delayed Puberty
The reassuring part is that constitutional delay is by far the most common reason a boy is still short at 16. It does not change the ultimate destination, just the timetable for getting there.
How Limbs and Trunk Grow at Different Rates
Growth after 16 doesn’t happen uniformly across the body. Hands and feet tend to stop growing first, followed by the forearms and shins, then the upper arms and thighs, and finally the trunk and spine. This pattern, where the farther body segments from the center finish growing before the closer ones, has been documented in longitudinal studies of adolescent limb growth.8PubMed. A longitudinal analysis of the growth of limb segments in adolescence
This is why a 16-year-old boy sometimes looks lanky or out of proportion: his arms and legs may have nearly reached adult length while his torso still has catching up to do. That last bit of height gain in the late teens often comes from the spine lengthening rather than the legs getting longer. It also explains why shoe size stabilizes well before a boy reaches his full adult height. If your feet haven’t changed size in a year but you’re still 16 or 17, that doesn’t mean your height is locked in. It just means the distal growth plates closed first, as expected.
The Face Keeps Changing After Height Stops
One of the less obvious forms of growth after 16 is craniofacial growth, particularly the jaw. A study tracking males from age 16 to 20 found statistically significant mandibular growth during both the 16-to-18 and 18-to-20 age windows.9PubMed. Facial growth in males 16 to 20 years of age The lower jaw continued to move forward and downward, the chin became more prominent, and overall facial proportions shifted. This is one reason a 20-year-old man’s face often looks distinctly different from his face at 16, even though his standing height may not have changed much.
This lingering facial growth has practical implications for anyone considering jaw surgery or orthodontic work. Surgeons and orthodontists typically prefer to wait until facial growth has slowed sufficiently, and for males that often means waiting until at least 18 to 20 rather than proceeding at 16. What looks like a jaw alignment problem at 16 might partially resolve, or change character, as growth continues.
Bone Density Keeps Building After You Stop Getting Taller
Even once the growth plates have fused and height gains stop, the skeleton is not finished developing. Young men continue to gain bone mass and bone size well into their twenties through a process sometimes called “consolidation.” During this phase, bones get wider and denser rather than longer. Research tracking bone development found that bone size kept increasing even after the growth plates closed, with little change in the internal density of the bone itself. That suggests the continued gain in bone mass comes from the outer dimensions of bones expanding rather than from the existing bone tissue becoming more mineralized.10PubMed. Attainment of peak bone mass at the lumbar spine, femoral neck and radius in men and women: relative contributions of bone size and volumetric bone mineral density
Peak bone mass in men is typically reached somewhere in the mid-to-late twenties. This matters because the bone mass you accumulate by that point acts as your lifelong reserve against later bone loss. Building a bigger skeleton in your teens and twenties, through adequate nutrition, weight-bearing exercise, and sufficient calcium and vitamin D, is the best investment you can make against osteoporosis decades down the line. The fact that height growth has ended does not mean skeletal development has ended.
Predicting How Much Growth Remains
The most common clinical tool for estimating remaining growth is a bone-age X-ray, usually of the left hand and wrist. A radiologist compares the degree of growth plate maturation to reference standards and assigns a “bone age” that may or may not match the boy’s calendar age. If a 16-year-old has a bone age of 14, he likely has substantially more growth remaining than his peers. If his bone age is already 17, he’s close to done.
Automated methods have improved the accuracy of these predictions. One system based on computerized bone-age determination achieved a root-mean-square prediction error of about 3.3 cm for boys aged 10 to 15, which was modestly better than older manual methods.11The Journal of Clinical Endocrinology & Metabolism. Prediction of Adult Height Based on Automated Determination of Bone Age A newer model incorporating pubertal staging alongside bone age has narrowed the average prediction error further, down to nearly zero mean error in a validation cohort, though individual predictions can still miss by a few centimeters.12Journal of the Endocrine Society. Clinically Optimized Adult Height Prediction From Key Bone and Pubertal Stages: Prospective Validation to Adult Height
A simpler and freely available method is the mid-parental height formula: average the parents’ heights, add about 6.5 cm for a boy (or subtract for a girl), and that gives a rough target. A family-based study found this Victorian-era method explained about 40 percent of the variation in adult height, which sounds modest but is hard to beat without medical imaging.13European Journal of Human Genetics. Predicting human height by Victorian and genomic methods Heritability estimates for height land around 0.75 to 0.78, meaning genetics accounts for roughly three-quarters of the variation in adult stature, with the rest coming from nutrition, health, and environment.14Pediatric Research. Target Height as Predicted by Parental Heights in a Population-Based Study
Nutrition, Catch-Up Growth, and the Limits of Late Gains
For boys who were well-nourished throughout childhood, nutrition at 16 has relatively little effect on final height. The genetic program is mostly executing on schedule, and adding extra calories or protein will not push a boy past his genetic ceiling. However, for boys who experienced significant malnutrition or chronic illness earlier in life, the situation is different. Their bone maturation is often delayed along with their height, which paradoxically preserves growth potential. A review of catch-up growth in malnourished children found that when environmental conditions improved, through better nutrition, treatment of underlying disease, or adoption into more favorable settings, substantial catch-up growth was common. In some cases, growth continued into the early or mid-twenties, and near-complete reversal of stunting was possible.15PubMed. Is complete catch-up possible for stunted malnourished children?
This is a genuinely optimistic finding. It means that for the large number of boys worldwide whose growth was compromised by poverty or illness, the window for catching up extends well beyond the age at which well-nourished boys finish growing. The mechanism is the same one that helps constitutional late bloomers: delayed puberty and delayed bone maturation keep the growth plates open longer, giving the body more time to close the gap once conditions improve.
Aromatase Inhibitors and Other Clinical Approaches
Because estrogen is the hormone that drives growth plate closure, researchers have explored whether blocking estrogen production could extend the growth window and increase adult height. Aromatase inhibitors, drugs that prevent the body from converting testosterone into estrogen, have been trialed for this purpose in boys with short stature or predicted short adult height.16PubMed Central. Aromatase inhibitors for short stature in male children and adolescents The idea is straightforward: less estrogen means slower plate fusion, which means more time to grow.17PubMed. Use of aromatase inhibitors to increase final height
Early results showed that aromatase inhibitors could increase predicted adult height by several centimeters, but enthusiasm has been tempered by concerns about long-term safety. Estrogen does important things beyond closing growth plates. It helps build bone density, and suppressing it during adolescence could theoretically weaken the skeleton in ways that show up decades later. The evidence base is still limited, and these drugs are not widely recommended for this purpose outside of research settings. For most healthy boys who are simply shorter than they’d like, the risk-benefit calculation does not favor pharmacological intervention.
Population-Level Trends in Growth
Today’s boys are, on average, taller than boys a century ago. This secular trend in height has been well documented across many countries and is attributed primarily to improvements in nutrition, sanitation, and overall health. In Northern Europe, where the trend has been studied most extensively, adult height has largely plateaued, suggesting that populations with excellent nutrition and healthcare have essentially reached their genetic potential.18PubMed. The secular trend in human physical growth: a biological view
Interestingly, one study tracking children born between 1978 and 1993 found that the secular increase in height was clearly visible at ages 4, 9, and 14, but had essentially disappeared by age 18.19PubMed Central. Secular trends in physical growth, biological maturation, and intelligence in children and adolescents born between 1978 and 1993 In other words, children were taller at younger ages compared to earlier cohorts, but final adult height did not change much. The likely explanation is that more recent generations were reaching their adult height earlier due to earlier puberty and faster maturation, not that they were growing to a taller endpoint. This is a useful reminder that looking taller at 14 or 16 does not necessarily mean ending up taller at 20. The timing of growth has shifted even when the final destination has not.
Population Differences in Fusion Timing
Growth plate closure does not follow the same timetable in every population. A forensic study comparing knee ossification in modern Australian and North American children found that the timing of active knee fusion and complete fusion varied between groups, with interpopulation differences becoming especially prominent in later adolescence and early adulthood for males.20Journal of Forensic Sciences. New PMCT multi‐indicator ossification standards for age estimation of the knee in modern Australian and North American children Active knee fusion occurred in Australian males between ages 12 and 18, while North American males showed a slightly different range. The study’s authors recommended using population-specific standards, particularly for the later fusion stages after age 15 to 16, to avoid applying one group’s timeline to another.
This matters if you’re trying to interpret a bone-age X-ray or a doctor’s estimate of remaining growth. Standards developed from one ethnic or geographic population may not precisely apply to a boy from a different background. The broad strokes are similar everywhere, boys grow later and longer than girls, growth plates close in the late teens to early twenties, but the fine details shift enough that a one-size-fits-all answer about growth after 16 does not exist.
When Ongoing Growth at 16 Warrants Medical Attention
For most 16-year-old boys, continued growth is completely normal and expected. But in rare cases, unusual growth patterns at this age signal something worth investigating. A boy who is growing much faster than peers at 16, particularly if he is already very tall, might warrant evaluation for pituitary gigantism, a condition where excess growth hormone drives abnormal height gain. Tall stature is formally defined as height more than two standard deviations above the average for age and sex, and distinguishing constitutional tall stature from pathological causes during the transition age is clinically important because the systemic complications of untreated gigantism are serious.21SpringerLink / Journal of Endocrinological Investigation. Tall stature and gigantism in transition age: clinical and genetic aspects-a literature review and recommendations
On the other end, a boy who shows no signs of puberty by 16, or whose growth has completely stalled without explanation, should also see an endocrinologist. Constitutional delay is harmless and self-resolving, but it can only be diagnosed after ruling out other causes like growth hormone deficiency, thyroid disorders, or chronic illness. A bone-age X-ray is usually the first step in that evaluation, providing a snapshot of how much skeletal maturation has occurred and how much growth potential likely remains.