Puberty typically ends between ages 15 and 17 for girls, and between 16 and 18 for boys. But “ending” isn’t as clean-cut as it sounds. Some physical changes, like height growth and bone development, can continue into your early 20s even after the most visible signs of puberty are complete.
When Puberty Ends for Girls
Girls generally finish puberty around age 15 to 17. By this point, breasts have reached their adult size, menstrual cycles have become more regular, and pubic hair has fully developed. Most girls reach their peak height by age 16, though some continue growing through age 20.
The total duration of puberty in girls is usually about four to five years. Girls who start puberty earlier tend to go through it more slowly, while those who start later often progress through the stages faster. This appears to be the body’s way of compensating, so most girls end up finishing around a similar age regardless of when they started.
When Puberty Ends for Boys
Boys start puberty later than girls, usually between ages 9 and 14, and they finish later too. Most boys complete puberty somewhere between 16 and 18, though continued changes in muscle mass, body hair, and facial hair can stretch into the early 20s. Voice deepening, one of the more noticeable changes, is typically complete by 16 or 17.
Height growth in boys peaks later than in girls, usually around 13 to 15, with final adult height often reached by 18 or 19. The growth plates in the long bones of the legs don’t fully close until around age 19 in most males, which is why a small amount of height gain after 18 is still possible.
What “Finished” Actually Means
Doctors track puberty using a five-stage scale. Stage 5 is the final phase, representing full physical adulthood. Reaching this stage means the reproductive system is mature, adult body proportions are established, and sex hormone levels have stabilized to their adult range.
But some development continues well past Stage 5. Bone density keeps increasing into the mid-20s. The growth plates at the wrist and ankle, for instance, don’t fully fuse until around 15 to 19 in females and around 19 in males. And the brain keeps maturing until the mid-to-late 20s, with the areas responsible for decision-making, impulse control, and long-term planning among the last to finish developing. So while the hormonal and reproductive changes of puberty wrap up in the teens, the body isn’t truly “done” developing for several more years.
What Affects How Long Puberty Takes
Genetics is the biggest factor. Twin studies show that heredity accounts for roughly 50 to 80 percent of the variation in puberty timing. If your parents went through puberty early, you likely will too.
Body weight also plays a role. Higher body fat is linked to earlier onset of puberty, particularly in girls. This tracks with a broader historical trend: as nutrition and overall health have improved over the past century, puberty has been starting earlier in both sexes. Girls who begin earlier tend to spend more time in puberty overall, sometimes taking a year or more longer to reach the final stage compared to girls who start later.
Chronic stress, certain medical conditions, and exposure to hormone-disrupting chemicals can also shift the timeline in either direction, though these effects are smaller than genetics and nutrition.
When Puberty Is Considered Late
For boys, puberty is considered delayed if there are no signs of development by age 14. For girls, the threshold is typically age 13 with no breast development, or age 15 with no menstrual period. Delayed puberty is more common in boys and often runs in families, a pattern sometimes called “late blooming.” In most cases, puberty eventually starts on its own and progresses normally, just on a shifted timeline. When it doesn’t, a doctor can evaluate whether an underlying hormonal or nutritional issue needs to be addressed.
On the other end of the spectrum, puberty that begins very early (before age 8 in girls or age 9 in boys) is called precocious puberty. It can compress the growth window and lead to a shorter adult height if not evaluated.