Growth plate calculator: are yours still open?
Five questions about your age, your growth spurt and your puberty milestones. You get an estimate of whether your growth plates are still open and roughly how much growing time is left.
What growth plates are
Growth plates, or epiphyseal plates, are thin layers of cartilage near the ends of the long bones in children and teens. Cartilage cells in the plate multiply, stack up, and are gradually replaced by bone. That is how a bone gets longer, and it is the only way it can.
During puberty, rising sex hormones first speed the plates up, which is the growth spurt, and then shut them down. Estrogen does the shutting down in both boys and girls. The cartilage thins until bone bridges across it. Doctors call that fusion, and once it happens the bone stays the length it is.
Growth plate closure by age
Typical timing. Individual teens run up to two years earlier or later, usually in line with when their parents went through puberty.
| Age | Girls | Boys |
|---|---|---|
| 8 to 11 | Puberty begins. Plates wide open, growth speeding up. | Steady childhood growth. Plates wide open. |
| 11 to 13 | Peak growth spurt, then first period for most. | Puberty begins. Growth starts to speed up. |
| 13 to 15 | Growth slows sharply. Plates begin to fuse. | Peak growth spurt. |
| 15 to 17 | Most have reached adult height. | Growth slows. Plates begin to fuse. |
| 17 to 20 | Plates closed in nearly all. | Most reach adult height by 18. Late bloomers finish by 20. |
How the calculator estimates your status
It starts from where the average teen of your age and sex is on the CDC growth curve, then adjusts for the three things that best predict timing without an X-ray: how much you grew in the last year, where you are relative to your growth spurt, and how long ago a late-puberty milestone happened.
Recent growth counts most. A plate that is adding height is open by definition. For a height estimate to go with the timing, use the height calculator, or read the growth plate guide.
Frequently asked questions
Can growth plates stay open longer?
Not through anything you can do yourself. Plates fuse when puberty hormones, mainly estrogen in both sexes, tell them to, and that timing is largely genetic. No food, stretch, supplement or sleep schedule delays it. Doctors can slow fusion with prescription medicine in specific medical conditions, but that is a specialist decision, not a growth hack. What you can do is get the most from the time they are open: sleep 8 to 10 hours, eat enough protein, calcium and vitamin D, and stay active.
How to tell if growth plates are closed without an X-ray
You cannot know for certain without one, but the signs are fairly reliable together. Plates have probably closed if your height has not changed in 12 months, your shoe size has been stable for a year or more, and you are at least two years past your first period (girls) or past your voice settling (boys). If you are still gaining height, they are open.
At what age do growth plates close?
In most girls between 14 and 16, and in most boys between 16 and 18. Different bones finish at different times: hands and feet first, then the legs, with the spine and collarbone last, sometimes into the early twenties.
Can you grow taller after growth plates close?
No. Once a plate has fused, that bone cannot get longer. Better posture can recover a centimetre or two of height you already have, and height varies by up to 2 cm between morning and evening, but neither is new growth.
Does lifting weights close growth plates early?
No. That is a myth. Supervised strength training with good form does not damage growth plates or stunt growth, and pediatric and sports medicine bodies consider it safe for teens. The real risk to a plate is a fracture through it, which comes from falls and collisions far more often than from the gym.
How is a growth plate X-ray done?
A doctor orders a single X-ray of the left hand and wrist. It takes a few minutes and uses a very small dose of radiation. A radiologist compares the bones with reference images to give a "bone age", which shows how much growing is left.