Penile length measurement is rarely used to monitor pubertal progress.
The timing of puberty
differs in each individual. Tanner stage 5 is characterized by adult genitalia. To answer your question, though, mean penile stretch length (non-erect) by late puberty is around 3.75 in, for white males. Mean erect adult human penis is between 5 and 6 inches in length.
...The doctor will see you now ›