When does a penis stop growing?
Many years ago, Dr. Tanner divided adolescence into five stages to make the progress in changing from a child to an adult easier to track. These stages are now known as the Tanner Stages.
Stage 1: This is the stage you were in as a child, before puberty started. No external changes are noticeable in the genitals and there is no secondary sex characteristics, such as hair growth. (Testicle volume is 1 to 3 milliliters.)
Stage 2: This is when puberty generally is said to start, even though the hormones causing sexual changes have been rising for almost a year. The testicles and the scrotum begin to enlarge. (Testicle volume is 4 to 6 milliliters.) Toward the end of this stage some hair growth may be detected near the base of the penis. Stage 2 normally begins somewhere between age 9 and 16. The average age is between 11 and 12.
Stage 3: The penis begins to lengthen. The testicles and scrotum continue to grow. (Testicle volume is 7 to 16 milliliters.) Pubic hair, the hair around your genitals begins to grow. It starts out fine, but by the end of this stage it takes on a coarser texture. It is during this stage that most boys experience their growth spurt. Leg and arm hair begins to appear. The voice also begins to change toward the end of this stage. Stage 3 normally begins two years after stage 2. The average age is between 13 and 14.
Stage 4: In addition to lengthening, the penis begins to widen in circumference. The testicles and scrotum continue to grow. (Testicle volume is 12 to 24 milliliters.) Pubic hair now covers most of the groin area between the thighs. Underarm hair begins to grow at the beginning of this stage. Mid-way, facial hair begins to develop on the upper lip and on the chin. The voice continues to deepen and growth begins to slow down. Stage 4 normally begins one to two years after stage 3. The average age is between 14 and 15.
Stage 5: While all growth has not stopped, the body has taken on an adult shape. The shoulders begin to widen and chest hair begins to appear. Facial hair is more complete and shaving is deemed necessary. The pubic hair covers the groin and has spread to the inside thighs. The penis and testicles now have an adult shape and stop growing (Testicle volume is 16 to 27 milliliters.) Stage 5 normally begins two years after stage 4. The average age is between 16 and 17.
To estimate what stage of development you are in, see the Tanner Stage Calculator for Boys.