When Do Children Stop Growing?
The short answer is that girls usually finish between 14 and 16, and boys between 16 and 18. But the age is a consequence, not a cause — what actually ends growth is a biological event that happens on the child's own schedule. Understanding that event explains why the ages vary so much between children, why the answer differs by two years between sons and daughters, and why predictions get sharper as a child gets older.
The short answer
| Spurt begins | Peak growth | Usually finished | |
|---|---|---|---|
| Girls | 9 – 11 | 11 – 13 | 14 – 16 |
| Boys | 11 – 13 | 13 – 15 | 16 – 18, sometimes 19 – 20 |
The two-year offset between the sexes runs through the whole sequence. It is the reason a class of 12-year-olds often has girls a clear head taller than the boys, and the reason that gap reverses entirely by 16. Girls also start their spurt from a shorter base and spend less time growing before it, which accounts for most of the eventual difference in adult height between men and women.
What actually stops growth
Long bones do not lengthen along their whole shaft. Near each end sits a band of cartilage — the epiphyseal plate, or growth plate — where cartilage cells divide, are pushed outward, and are progressively replaced by bone. That process is what makes a bone longer.
During puberty, rising sex hormones do two things at once. In the early phase they accelerate the plate dramatically, producing the growth spurt. At the same time, oestrogen steadily drives the cartilage to be replaced by solid bone. Eventually replacement outpaces production, the cartilage band is used up, and the plate fuses. From that point the bone's length is fixed.
Oestrogen closes the plates in both sexes. Boys produce oestrogen too, converted from testosterone, and it is that conversion that ends male growth. Because girls reach high oestrogen levels around two years earlier, their plates fuse earlier — which is the underlying reason for the whole two-year offset.
The plates do not all close at once. Those in the hands and feet fuse relatively early, which is why teenagers often stop needing new shoes a year or more before they stop needing longer trousers. The spine contributes the last centimetre or two, and continues fractionally after the leg bones have finished.
Girls: the first period is the key landmark
Menarche is the most useful marker parents have, because it arrives at a fairly consistent point in the sequence — after peak growth velocity has already passed. By the time a girl has her first period, the fastest part of her growth is behind her.
Typical remaining growth after menarche is around 5 to 7.5 cm, spread over one to two years and slowing throughout. There is real variation: girls who start unusually early tend to have more left, and those who start late rather less. A girl who has had periods for two years and has grown under a centimetre in the last twelve months is almost certainly finished.
Boys: later, longer, and less clearly signposted
Boys have no single equivalent landmark. The sequence begins with testicular enlargement, typically around 11 to 13, followed roughly a year later by the acceleration in height. Voice change and facial hair arrive relatively late — usually well after peak growth velocity, so a boy whose voice broke a year ago has already passed his fastest period.
Boys also spend about two extra years in pre-pubertal growth before the spurt begins, adding to their starting height, and their peak velocity is somewhat higher. Both factors feed into the adult height difference.
The tail is longer too. It is not unusual for a boy to add one to three centimetres between 17 and 19, and late developers can still be measurably growing at 20.
Signs a child is nearly finished
- Shoe size has been stable for a year or more. Feet finish early, so this is an early warning that the end is approaching — not that it has arrived.
- Trouser length has not changed in a year. A more reliable signal than shoes, since leg length is where most late growth appears.
- Measured growth under about 1 cm in twelve months, with puberty complete. This is the strongest at-home indicator.
- Puberty finished well over a year ago. In girls, periods established for two-plus years; in boys, full voice change and facial hair for a similar period.
Measure properly before drawing conclusions: same time of day, shoes off, heels and back against a wall. Height varies by up to a centimetre between morning and evening as spinal discs compress under the day's load, which is enough to manufacture a phantom growth spurt or hide a real one.
How a doctor can tell for certain
The definitive test is a bone age X-ray — a single image of the left hand and wrist. The pattern of ossification in those small bones shows how far skeletal maturity has progressed and whether the plates are open, closing or fused. A radiologist compares the image with a standard atlas and reports a skeletal age, which may sit ahead of or behind the child's actual age.
That comparison is genuinely informative. A 14-year-old with a bone age of 12 has substantially more growth ahead than his birthday suggests — the classic late-developer picture. A 12-year-old with a bone age of 14 has less. Adult-height estimates built on bone age are meaningfully more accurate than those built on chronological age, which is why paediatric endocrinologists order it when the answer matters.
Why predictions sharpen with age
An estimate for a six-year-old rests almost entirely on genetics and an assumption of average pubertal timing — and timing varies by three or four years between normal children. An estimate for a fifteen-year-old rests mostly on measured facts: how tall they already are, how much of puberty is behind them, how fast they are still growing.
This is why an honest calculator reports a wider range for younger children and a narrower one for older ones. The predictor on this page does exactly that — it widens the interval for younger ages, incomplete inputs and disagreement between methods, rather than reporting a fixed margin that would be misleading at both ends.
Frequently asked questions
At what age do children stop growing?
Most girls finish between 14 and 16, most boys between 16 and 18, and some boys add a little more into their late teens. Growth ends when the growth plates close, which follows the completion of puberty rather than any particular birthday.
What are growth plates and why do they close?
They are bands of cartilage near the ends of long bones where new bone is added. Rising oestrogen during and after puberty gradually converts that cartilage to solid bone. Once a plate has fully ossified it cannot lengthen again, in either sex.
How much does a girl grow after her first period?
Usually about 5 to 7.5 cm over the following one to two years. Menarche arrives after peak growth velocity has passed, so most of the spurt is already behind her. Girls who start early tend to have somewhat more remaining.
How can I tell if my child has stopped growing?
Stable shoe size for a year, unchanged trouser length, and under about 1 cm of measured growth in twelve months with puberty complete. A hand and wrist X-ray gives the definitive answer by showing whether the plates have closed.
Can anything restart growth after the plates close?
No. Once fused, no supplement, stretch, hormone or device lengthens bone. Growth hormone treatment works only while the plates are open and is prescribed for specific diagnosed conditions.
This page is general information for parents and carers, not medical advice, diagnosis or treatment. Ages given are typical ranges, and healthy children vary widely around them. If you are concerned about your child's growth or pubertal timing, speak to a paediatrician or family doctor.