Growth plates usually close in the mid to late teens. In girls they typically close between ages 13 and 16. In boys they close later, usually between 15 and 19. Once a growth plate closes, the bone can no longer add length, so a child has reached their adult height. The exact timing depends on puberty, genetics, and overall health.
If you are reading this at 11pm with a worried feeling, you are not alone. Most parents who search this question are really asking something quieter: how much time do we have left.
This guide gives you the honest answer. The timeline, the signs, and what actually matters while the window is still open.
What Are Growth Plates?
Growth plates are areas of soft, growing cartilage near the ends of a child's long bones, like the bones in the legs and arms. They are where new bone is made. As long as the plates stay open, a child can keep growing taller.
During puberty, rising hormone levels signal the plates to slowly harden into solid bone. Doctors call this fusion. When a plate fuses, that bone is done growing. According to Nemours KidsHealth, this is a normal part of finishing development, not a problem to fix.
When Do Growth Plates Close in Girls?
In girls, growth plates usually close between ages 13 and 16. Girls tend to start puberty earlier than boys, so their fastest growth and their final growth both happen sooner. Many girls reach close to their adult height within a year or two of their first period.
This is a range, not a fixed date. A girl who starts puberty later may keep growing into her later teens. A girl who starts early may finish sooner.
When Do Growth Plates Close in Boys?
In boys, growth plates usually close between ages 15 and 19. Boys start puberty later than girls, so their growth window stays open a couple of years longer on average. That is why a boy who is shorter than his classmates at 14 can still have meaningful growing left to do.
Again, the range matters more than the number. Late puberty often means a later close. This is the honest version of the old "he is a late bloomer" line.
Growth Plate Timeline: Boys vs Girls
Here is the difference at a glance.
| Topic | Girls | Boys |
|---|---|---|
| Growth plates typically close | 13 to 16 years | 15 to 19 years |
| Growth window open | Childhood to early or mid teens | Childhood to mid or late teens |
| Main driver of closure | Puberty hormones | Puberty hormones |
| Height gain possible after closure | No | No |
What Causes Growth Plates to Close?
Puberty is the main driver. As a child moves through puberty, hormone levels rise and gradually tell the cartilage in the growth plates to harden into bone. When that process finishes, the plate is closed.
This is why the timing of puberty matters more than a child's current height. Two boys can be the same height at 13, and the one who enters puberty later will usually have a longer runway.
How Do You Know If Your Child's Growth Plates Are Still Open?
You cannot tell for certain by looking. The only reliable way to know is a bone age X-ray, usually of the hand and wrist. A pediatrician or pediatric endocrinologist can read it and compare bone age to actual age.
There are softer signs that a child is still growing: needing larger shoes, outgrowing trousers, and steady gains at checkups. But if you genuinely need to know whether the window is open, ask your pediatrician about a bone age scan. A guess from a forum is not the same as an X-ray.
Can You Still Grow Taller After Growth Plates Close?
No. Once growth plates fuse, the long bones cannot add length, and no supplement, stretch, or exercise reopens them. Claims that a product can keep growth plates open longer or restart them are not supported by evidence.
This is the part the supplement industry tends to go quiet about. It is also the most important thing for a parent to understand, because it changes what you should focus on.
You do not get the growth window back. That single fact is what this whole topic comes down to.
What Actually Matters While the Growth Window Is Open
Here is the honest framing. Genetics sets the ceiling. It accounts for roughly 60 to 80 percent of a child's final height. You cannot change that.
Nutrition, sleep, and activity influence the rest. They do not raise the ceiling. What they do is decide whether a child reaches the upper end of their own genetic range, or leaves height on the table because of a gap that was fixable.
The research is specific about this. A study of 140 children found that correcting a real zinc shortfall supported measurably more growth than a placebo over six months. But a large trial published in JAMA Pediatrics, following more than 8,000 children for three years, found that giving vitamin D to kids who were already getting enough did not add height.
Read those two findings together and you get the real rule. Fixing a genuine nutrition gap can help. Piling extra nutrients onto a child who is already well nourished does not. The job is to close gaps, not to chase inches.
For most kids the common gaps are calcium, vitamin D, zinc, magnesium, and omega 3, especially for picky eaters who skip fish, dairy, or vegetables. The NIH Office of Dietary Supplements sets the daily calcium target at 1,000 mg for ages 4 to 8 and 1,300 mg for ages 9 to 18. Many children fall short.
This is the thinking behind Tallori. It is a zero sugar daily gummy built to fill those common gaps during the ages 5 to 16 window, when the plates are still open and nutrition can still do its job. It will not make a child taller than their genetics allow. Nothing will. What a complete formula can do is make sure a fixable gap is not the reason a child finishes short of their own potential.
The Bottom Line
Growth plates usually close around 13 to 16 in girls and 15 to 19 in boys, and the timing follows puberty more than the calendar. After they close, height stops, and nothing reopens them.
While the window is open, the honest goal is simple. Support good sleep, keep your child active, and close any real nutrition gaps so their body can grow as far as its genetics allow. If you want to understand the supplement side of that, read do height growth gummies actually work for kids and our science-backed parent guide to kids growth supplements.
Keep Reading
- Do Height Growth Gummies Actually Work for Kids?, the science behind growth supplements
- Kids Growth Supplements: A Science-Backed Parent Guide, what to look for and what to skip
- Best Growth Gummies for Children in 2026, an honest ranking of the major brands
Frequently Asked Questions
At what age do growth plates close?
Growth plates usually close in the mid to late teens. In girls they typically close between ages 13 and 16. In boys they close later, usually between 15 and 19. The exact timing depends on when a child goes through puberty, along with genetics and overall health.
Can growth plates reopen after they close?
No. Once growth plates fuse into solid bone, they cannot reopen, and the long bones cannot add length. No supplement, exercise, or stretching routine reopens a closed growth plate. Any product claiming to do so is not supported by evidence.
How can I tell if my child's growth plates are still open?
You cannot tell for certain by looking. The reliable method is a bone age X-ray, usually of the hand and wrist, read by a pediatrician or pediatric endocrinologist. Softer signs that growth continues include needing bigger shoes and steady height gains at checkups.
Do girls or boys stop growing first?
Girls usually stop growing first. Because girls start puberty earlier, their growth plates typically close around 13 to 16, while boys' plates close later, around 15 to 19. On average, boys keep growing a couple of years longer than girls.
Can you still grow taller after 18?
For most people, no. By 18 the growth plates have usually closed, especially in girls. Some boys with later puberty may add a small amount of height into their later teens, but significant growth after 18 is uncommon. A bone age X-ray can confirm whether any window remains.
Does nutrition affect when growth plates close?
Nutrition does not meaningfully change the timing of growth plate closure, which is driven mainly by puberty hormones. What nutrition does affect is how much growth a child achieves while the plates are still open. Correcting real nutrient gaps supports growth; closure timing stays tied to puberty.
Can a supplement keep growth plates open longer?
No. No supplement keeps growth plates open longer or delays their closure. A good growth supplement works only while the plates are naturally open, by helping fill nutrition gaps so a child reaches the upper end of their own genetic height range. It does not extend the window itself.
Medical disclaimer: This article is for information only and is not medical advice. Growth concerns should be discussed with your pediatrician, who can order a bone age X-ray and check for any underlying issues. Last updated 24 May 2026.