Tanner Stage 5 is the final stage of puberty, representing full physical maturity. It’s the endpoint of a five-stage scale that pediatricians use to track how a young person’s body is developing. Reaching Stage 5 means the major physical changes of puberty are complete, from growth in height to the development of adult body hair, genitalia, and breast tissue.
How the Tanner Scale Works
The Tanner scale was developed in the late 1960s and early 1970s by James Tanner and W.A. Marshall, who studied the progression of puberty in British children. They identified five distinct stages of development, starting at Stage 1 (the prepubescent body) and ending at Stage 5 (the fully mature adult body). The scale tracks different features depending on sex: genital development and pubic hair in boys, breast development and pubic hair in girls.
Pediatricians still use this system today. It helps them assess whether a child’s development is progressing on a typical timeline, or whether it may be unusually early (precocious puberty) or delayed.
What Stage 5 Looks Like in Boys
In boys, Tanner Stage 5 means the genitalia have reached their adult size. The testes are greater than 4.5 centimeters in length, and the penis typically reaches its mature size by around age 16.5. Pubic hair has spread to the inner thighs in an adult distribution pattern, and facial hair appears on the sides of the face. The overall body has taken on what’s described as the mature male physique, with broader shoulders and increased muscle mass.
Voice changes, which begin earlier in puberty, are largely complete by this point. Research tracking boys through puberty found that the most abrupt drop in voice pitch happens between Stages 3 and 4, with more gradual settling through Stage 5. Height growth stops by around age 17, as the growth plates in the long bones close. The growth spurt that defines earlier stages of puberty has wound down significantly by the time a boy reaches full maturity.
On average, boys reach genital Stage 5 at about 15.6 years, based on a large Danish study of more than 7,000 boys. Pubic hair tends to reach its adult pattern slightly earlier, at around 14.7 years. But there’s wide individual variation. Original research by Marshall and Tanner found that some boys completed genital development in as little as 1.8 years after it started, while others took as long as 4.7 years. In 95% of boys, the genitalia began developing between ages 9.5 and 13.5, with full maturity reached anywhere between ages 13 and 17.
What Stage 5 Looks Like in Girls
In girls, Tanner Stage 5 describes the adult breast shape. The key feature is that the areola has receded to match the general contour of the breast, rather than projecting as a separate mound (which is the hallmark of Stage 4). This final breast shape is typically reached by an average age of 15, though a large population study found the average closer to 15.8 years when assessed across a broad cohort of more than 7,600 girls.
Pubic hair, as in boys, has spread to the inner thighs in an adult distribution. Girls in Stage 5 have also reached their final adult height, with growth typically stopping by around age 16. Menstruation has usually been established for at least a couple of years by this point, though it can take time after periods begin for cycles to become fully regular and consistently ovulatory.
The Wide Range of Normal
One of the most important things to understand about Tanner stages is how much the timing varies from person to person. The Danish study found that the range for reaching genital Stage 5 in boys spanned from about 12.6 to 18.6 years. For breast Stage 5 in girls, the range was even wider: roughly 11.9 to 19.7 years. A 13-year-old who looks fully mature and a 17-year-old who is still developing can both be completely normal.
This variability is one reason the Tanner scale exists in the first place. Rather than relying solely on a child’s age, it gives doctors a way to assess where someone is in the process of puberty regardless of when they started. Two teens the same age can be at entirely different stages, and that alone is not a cause for concern.
What Happens After Stage 5
Reaching Tanner Stage 5 doesn’t mean every aspect of physical development is instantly finished. Bone density continues to increase into the mid-20s. Some boys continue to develop chest and facial hair well into their early 20s. Body composition can still shift. But the major, visible markers of puberty that the scale tracks, including genital size, breast shape, pubic hair pattern, and height, have reached their adult form. From a clinical standpoint, puberty is complete.