The only reliable way to check whether your growth plates are closed is through imaging, most commonly an X-ray of the left hand and wrist. A trained clinician compares the image against a reference atlas to determine bone age, and if the small bones of the hand, wrist, and the ends of the forearm bones show complete fusion, the growth plates are closed and longitudinal bone growth has stopped. No blood test, home measurement, or online calculator can give you a definitive answer, but there is more to the process than just ordering an X-ray.
What a Growth Plate Actually Is and Why It Closes
Growth plates are thin layers of cartilage sitting near the ends of long bones. During childhood and adolescence, specialized cells in these plates keep dividing and producing new cartilage, which gradually hardens into bone and makes the bone longer. This is how you grow taller. The process does not go on forever. Under the influence of estrogen, the dividing cells in the growth plate gradually exhaust their ability to keep reproducing. Eventually the cartilage is fully replaced by solid bone, blood vessels move in, and the plate fuses shut.1PubMed Central. The growth plate: a physiologic overview Once that happens, the bone can no longer lengthen.
Estrogen drives this process in both males and females. Boys produce estrogen too, converted from testosterone by an enzyme called aromatase. This is why conditions that interfere with estrogen production or signaling can delay growth plate closure, sometimes dramatically.2PubMed Central. Effects of estrogen on growth plate senescence and epiphyseal fusion Estrogen does not just flip a switch. It works through receptors found across different zones of the growth plate, accelerating the exhaustion of the cells that fuel growth. During puberty, rising estrogen levels first help drive the growth spurt, then gradually shut it down by wearing out the plate’s regenerative capacity.3Clinical and Experimental Pediatrics. Growth plate closure and therapeutic interventions
When Growth Plates Typically Close
Growth plates do not all close at the same time. The body follows a predictable sequence, with the feet closing first and the wrist closing later. A cross-sectional MRI study of adolescents and young adults mapped this pattern in detail. In girls, the earliest closures happened around age 14 to 15, and by age 19 all of the studied sites were fused. In boys, closures began around 15 to 16, and by age 21 all sites were fully fused. The sequence moved upward: the heel bone closed first, then the ankle, then the knee, and finally the wrist.4PubMed Central. A cross-sectional magnetic resonance imaging study of factors influencing growth plate closure in adolescents and young adults
One often-overlooked site is the inner end of the collarbone. This is one of the very last growth plates in the body to fuse, and it can stay open well into the twenties. A CT study found that complete union of the collarbone growth plate first appeared at age 22 and was seen in everyone by age 27.5PubMed. Bone age determination based on the study of the medial extremity of the clavicle So even if the growth plates in your hand and knee have fused, the collarbone may still be finishing up. That said, the collarbone’s closure does not contribute to height, so for the purposes of “am I still getting taller,” the hand, wrist, and leg are the sites that matter.
The Standard Test for Growth Plate Status
If you want to know whether your growth plates are closed, your doctor will almost certainly order a single X-ray of your left hand and wrist. This has been the go-to method for decades. The image captures about 30 small bones, each maturing on a slightly different schedule, which gives a detailed picture of overall skeletal development. Two main methods are used to interpret the image. The Greulich-Pyle method compares the X-ray against a reference atlas of standard images, and a trained radiologist can read it in a few minutes. The Tanner-Whitehouse method scores individual bones more precisely and tends to be more reproducible, though it takes longer.6PubMed Central. Hand X-ray in pediatric endocrinology: Skeletal age assessment and beyond A third approach, the Fels method, also exists and uses slightly different criteria.7Frontiers in Pediatrics. Evaluation of Bone Age in Children: A Mini-Review
What the clinician is determining is your “bone age,” which may or may not match your calendar age. A 14-year-old girl whose bone age reads as 16 is closer to closure than her birthday suggests. A 15-year-old boy with a bone age of 13 likely has more growth ahead. If every bone in the image looks fully mature, the growth plates are closed.
The left hand is used by convention rather than for any deep biological reason. Standardizing on one side keeps results comparable across patients and studies. It also happens to be the non-dominant hand for most people, which was thought to be less affected by mechanical stress, though the practical difference is negligible.
Can You Check Without an X-Ray?
People often want to know if there is a way to figure this out at home. The honest answer is that no home method is reliable. That said, there are a few rough clues.
Foot growth tends to plateau before the main height growth spurt finishes. Distal body parts, meaning the extremities like feet and hands, reach their peak growth earlier than the trunk.8PubMed Central. The value of shoe size for prediction of the timing of the pubertal growth spurt Research on children’s foot measurements confirms that foot length stops correlating strongly with age around 10 to 12, well before most kids hit their peak height velocity.9Scientific Reports. Pediatric foot anthropometry and its correlation with growth assessment So if your shoe size has been stable for a year or two, it does not necessarily mean your growth plates are closed everywhere. It means the ones in your feet likely are, but your spine and legs could still be adding height.
Pubertal staging is another indirect indicator. Girls who have had their period for two or more years are typically approaching or past the end of their growth. Boys who have reached late Tanner stages of puberty (full facial hair, adult voice, etc.) are usually close. But “close” is vague, and individual variation is enormous. Some teens grow an extra inch or two after every outward sign of puberty seems complete. Others stop earlier than expected. These clues can narrow the window, but they cannot replace imaging.
AI-Assisted Bone Age Reading
In the last several years, artificial intelligence systems have entered the picture for reading hand and wrist X-rays. These algorithms analyze the image and spit out a bone age in seconds, and the early results are impressive. One study comparing an AI system to human radiologists found that the AI’s readings were significantly closer to the reference bone age, with an average deviation of about a third of a year compared to about four-fifths of a year for the human reader. Reading time dropped by roughly 87%.10PubMed Central. Artificial intelligence in bone age assessment: accuracy and efficiency of a novel fully automated algorithm compared to the Greulich-Pyle method Other deep learning approaches have shown similar performance, achieving discrepancies of about 0.8 years from manual assessment.11Medical Image Analysis. Deep learning for automated skeletal bone age assessment in X-ray images
For you as a patient, this means the turnaround on a bone age reading might be faster, and some institutions now use AI as a first read with a radiologist confirming. It does not change what you need to do: you still need the X-ray taken. The AI just reads it more consistently.
The Ethnicity Problem With Standard Atlases
The Greulich-Pyle atlas, the most widely used reference, was built from X-rays of white American children in the 1930s and 1940s. That has raised legitimate questions about whether it works well for children of different ethnic backgrounds. A systematic review and meta-analysis looking at this issue found that the atlas held up reasonably well for most groups, with no statistically significant differences between bone age and calendar age for Caucasian, Hispanic, or Asian female children. However, African females showed a small but significant advancement in bone age relative to their calendar age, averaging about four months ahead. Asian males showed larger discrepancies that varied by age, ranging from about one year behind at younger ages to half a year ahead at 17.12PubMed Central. Is the Greulich and Pyle atlas applicable to all ethnicities? A systematic review and meta-analysis
A separate study comparing American children of African and European descent found that individual variability was wide in every group. Prepubertal children of African descent had slightly more advanced skeletal maturation on average compared to children of European descent, but the spread within each group was large enough that any individual child could fall well above or below the atlas norms.13Pediatric Research. Skeletal Age Determinations in Children of European and African Descent: Applicability of the Greulich and Pyle Standards The practical takeaway is that a bone age reading is a useful estimate, not a laser-precise measurement. If your bone age comes back a few months ahead of or behind your calendar age, that gap might reflect normal individual variation or ethnic differences in maturation tempo rather than anything clinically concerning.
Alternatives to Hand and Wrist X-Ray
The hand X-ray is the standard, but it is not the only imaging option. In some clinical scenarios, particularly orthopedic evaluations, doctors image the growth plates of the knee or ankle directly using MRI. A study comparing ultrasound to MRI for assessing knee growth plate status found that ultrasound was actually more sensitive at detecting open growth plates in minors, though slightly less specific, and the examination took under three minutes compared to about 25 minutes for MRI.14PubMed Central. Forensic age assessment of the knee: proposal of a new classification system using two-dimensional ultrasound volumes and comparison to MRI Ultrasound is appealing because it does not involve radiation, but it is not yet widely used for routine bone age assessment. It shows up more often in forensic age estimation, where the goal is determining whether someone is a minor.
CT scans are used for specific sites like the collarbone, as mentioned earlier, but the radiation dose makes CT impractical for routine screening. MRI gives excellent detail of the growth plate itself and can show partial closure that an X-ray might miss, but it is expensive and slow. For the straightforward question of “are my growth plates open or closed,” a hand and wrist X-ray remains the simplest, cheapest, and fastest answer.
When Growth Plates Close Too Early or Get Injured
Sometimes growth plates close before they should. Premature growth arrest happens when some kind of insult damages part or all of the growth plate while it is still open. If the entire plate is affected, the bone simply stops growing and the limb ends up shorter than its partner on the other side. If only part of the plate is damaged, the bone can develop an angular deformity as the healthy side keeps growing while the damaged side does not.15PubMed Central. Risk Factor Analysis for Growth Arrest in Paediatric Physeal Fractures—A Prospective Study The most common cause of this kind of damage is fractures that cross the growth plate, particularly the type known as Salter-Harris fractures. Injuries that allow blood vessels to bridge across the fracture line are at higher risk for forming a bony bar that permanently halts growth at that site.16PubMed. Imaging of Pediatric Growth Plate Disturbances
This matters practically because a child who breaks a bone near a joint needs follow-up imaging to make sure the growth plate was not compromised. If a bony bridge does form, surgeons sometimes remove it surgically and place a spacer to allow resumption of growth. But the window for intervention is narrow and depends on catching the problem while enough growth potential remains.
Deliberately Closing a Growth Plate
Oddly enough, there are situations where surgeons intentionally close a growth plate. The procedure is called epiphysiodesis, and it is used in children with significant leg length discrepancies, typically when one leg is projected to end up between 2 and 5 centimeters longer than the other. The surgery is done percutaneously, meaning through small incisions, and either destroys the growth plate with drills or tethers it with metal implants so it cannot produce new bone. It is an outpatient procedure, kids bear weight early afterward, and complication rates in recent studies are under 10%, mostly minor.17Current Opinion in Pediatrics. Closing the growth plate: a review of indications and surgical options The timing is critical: the surgeon needs to operate while the growth plates are still open and with enough growth remaining so that the shorter leg catches up by the time both legs stop growing.
Environmental Chemicals and Bone Maturation
An emerging area of research looks at how environmental chemicals influence how fast the growth plate matures. Substances called endocrine-disrupting chemicals, found in plastics, personal care products, and industrial processes, can mimic or interfere with estrogen and other hormones. A study examining several of these chemicals in children found complex and sometimes contradictory effects. Some compounds were associated with advanced bone age in prepubertal girls, while others were associated with delayed bone maturation, and the effects differed depending on body weight and pubertal stage.18Ecotoxicology and Environmental Safety. Divergent effects of EDCs on bone maturation: Role of body mass index and puberty The research is still in early stages, and nobody is suggesting that chemical exposure is a major driver of growth plate timing for most children. But it underscores that bone maturation is sensitive to hormonal signals from many sources, not just the body’s own puberty machinery.
Growth Hormone, Aromatase Inhibitors, and the Quest for Extra Height
Because growth plate closure is the hard deadline for gaining height, there is natural interest in whether you can delay it. Two interventions come up frequently in this context. Growth hormone therapy is used in children with documented growth hormone deficiency or certain other conditions, and it does accelerate growth. However, high-dose growth hormone treatment also accelerates bone maturation, meaning the growth plates advance toward closure faster. In one study, treated children showed bone age advancing at a rate of about 3.6 years for every two calendar years, compared to the expected two years of maturation in that same period. The net effect on adult height was unclear because the faster growth was partly offset by the faster march toward closure.19PubMed Central. High dose growth hormone treatment induces acceleration of skeletal maturation and an earlier onset of puberty in children with idiopathic short stature
Aromatase inhibitors, which block the conversion of testosterone to estrogen, have been explored as a way to delay growth plate closure. Since estrogen is the key signal driving fusion, reducing estrogen levels could theoretically keep the plates open longer and allow more growth. There is evidence that locally generated estrogen from aromatase activity plays a central role in fusion.20PubMed. Delayed closure of epiphyseal cartilages induced by the aromatase inhibitor anastrozole. Would it help short children grow up? These drugs are sometimes used in boys with predicted short stature, though their use for this purpose remains controversial and is not universally endorsed by pediatric endocrinology guidelines. The long-term safety data is still being gathered, and the potential gain in adult height has to be weighed against hormonal side effects during a critical developmental period.
Genetic Conditions That Alter Growth Plate Behavior
Some children have growth plate abnormalities driven by genetics rather than hormonal timing. One well-studied example involves deficiency of the SHOX gene, which plays a role in how growth plate cartilage cells go through their normal life cycle of dividing, swelling, and then dying to make way for bone. When this gene is missing or impaired, the programmed cell death that normally occurs in growth plate cartilage is disrupted, leading to skeletal changes including disproportionately short limbs and characteristic wrist and forearm deformities.21Clinical Pediatric Endocrinology. Skeletal Deformity Associated with SHOX Deficiency SHOX deficiency is one of the more common genetic causes of short stature and is part of the picture in Turner syndrome. For children with these conditions, the growth plate is not working normally to begin with, so standard bone age readings can be less predictive of final adult height.
This highlights a broader point: a bone age X-ray tells you where you are on the maturation timeline, but it does not tell you everything about how much growth remains. Two children with the same bone age can have very different amounts of growth left, depending on their genetics, their growth velocity, and the underlying condition if one exists. A pediatric endocrinologist interprets the X-ray in context, alongside growth charts, family height, pubertal staging, and sometimes blood work for hormone levels.