Most girls reach their final adult height between ages 14 and 16. The exact age depends on when puberty started, but by 16, the growth plates in the long bones have fully fused in nearly all females, making further height gain impossible. Girls who enter puberty earlier tend to stop growing earlier, while those who develop later may continue growing into their late teens.
How Growth Plates Control Height
Height increases because of soft, cartilage-rich zones near the ends of long bones called growth plates. During childhood and puberty, cells in these plates divide and multiply, lengthening the bones. Eventually the cartilage hardens into solid bone, a process called fusion. Once a growth plate fuses, that bone can no longer get longer.
In girls, complete fusion of the growth plates in the lower leg bones can begin as early as age 12 and is finished in all females by age 16, with no significant differences across ethnic backgrounds. X-rays of the knee show complete bony fusion starting around age 14 in girls, compared to 15 or 16 in boys. This earlier closure is the main reason girls typically finish growing one to two years before boys do.
The Role of Estrogen
Estrogen is the hormone that both drives and ultimately ends the female growth spurt. During early puberty, low levels of estrogen stimulate a burst of growth by boosting growth hormone and its downstream signals. This is the classic growth spurt most girls notice between ages 10 and 13. As puberty progresses and estrogen levels climb, the hormone flips from accelerator to brake. High estrogen in late puberty causes the cartilage cells in the growth plates to exhaust their ability to divide, triggering fusion.
This dual role explains a few things. Girls who are exposed to high estrogen levels earlier (through early puberty) fuse their growth plates sooner and may end up shorter than expected. And in rare cases where the body cannot produce or respond to estrogen, growth plates stay open well past the normal age, and the person keeps growing slowly into adulthood.
How Much You Grow After Your First Period
A common belief is that getting your first period means growth is nearly over. That’s not quite right. The average girl gains about 7 cm (roughly 3 inches) after her first period, and some gain considerably more.
Data from the Fels Longitudinal Study, one of the longest-running growth studies in the U.S., shows the relationship clearly. Girls who start menstruating at age 10 grow an average of 10 cm (about 4 inches) afterward. Girls whose first period arrives at age 15 grow only about 5 cm (2 inches) after that point. The earlier puberty begins, the more post-period growth remains because the growth plates haven’t yet accumulated enough estrogen exposure to fuse. So a 10-year-old who just got her period still has several years of growth ahead, while a 15-year-old in the same situation is closer to her final height.
What Affects When You Stop Growing
The single biggest factor is the timing of puberty, which is largely genetic. If your mother was a late bloomer, you’re more likely to be one too. But several other factors influence how long your growth window stays open and how much height you ultimately gain.
- Nutrition: Chronic undernutrition during childhood and adolescence can delay puberty and slow bone growth. Adequate protein, calcium, and vitamin D support normal growth plate activity.
- Sleep: Growth hormone is released primarily during deep sleep. Consistently poor sleep during puberty can reduce the amount of growth hormone available for bone lengthening.
- Chronic illness: Conditions like celiac disease, inflammatory bowel disease, or poorly managed asthma (particularly long-term oral steroid use) can suppress growth and delay puberty.
- Constitutional delay: Some girls are simply late bloomers with no underlying medical problem. In one study, girls with constitutional delay didn’t get their first period until an average age of 15.6 years and didn’t reach their final height until about age 19. They typically ended up shorter than their mid-parental height would predict, but they did reach the adult height that bone-age assessments had forecast for them.
Early Puberty and Adult Height
When puberty starts unusually early, before age 8 in girls, it’s called precocious puberty. The initial growth spurt can make a child seem tall for her age, but the rapid estrogen exposure fuses the growth plates well ahead of schedule. Historical data on untreated girls with precocious puberty showed an average adult height of about 152 cm (just under 5 feet). With treatment that temporarily suppresses puberty hormones, girls gained roughly 5 cm more, averaging 157 cm (about 5 feet 2 inches), and continued growing an average of 12 cm after treatment was stopped.
The takeaway is that early puberty compresses the growth window. The bones mature faster than they lengthen, so less total height accumulates before the plates close for good.
How Doctors Check If You’re Still Growing
If there’s any question about whether a girl has finished growing, a doctor can order a bone age X-ray, typically of the left hand and wrist. This image shows the growth plates clearly. Open plates with visible cartilage gaps mean growth is still possible. Narrow or absent gaps mean the plates are fusing or already fused. The X-ray is compared to a standardized atlas that matches bone maturity to chronological age.
A bone age that’s younger than a girl’s actual age suggests she has more growth time remaining. A bone age that matches or exceeds her chronological age means she’s at or near her final height. Ultrasound of the knee is also emerging as a radiation-free alternative for assessing growth plate status, though hand X-rays remain the standard.
The Typical Timeline
Putting it all together, here’s what growth generally looks like for girls:
- Ages 8 to 13: Puberty begins. Breast development is usually the first sign, followed by a growth spurt of 2 to 3 inches per year at its peak.
- Ages 10 to 15: First period arrives, on average around age 12. Growth slows but continues for another 2 to 3 years.
- Ages 14 to 16: Most girls reach their final adult height. Growth plates in the long bones complete fusion.
- Ages 17 to 19: Late bloomers with delayed puberty may still be adding their last inch or two.
After growth plates fully close, no amount of nutrition, exercise, or supplementation will increase your skeletal height. Small fluctuations of up to half an inch throughout the day are normal due to spinal disc compression, but actual bone growth is finished.