At What Age Does Penis Growth Begin?

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Penis growth is influenced by the hormones of puberty. As such, the penis begins to grow more rapidly than usual between ages 10 and 14 and can continue to grow until ages 16 to 21. Many young men become concerned or self-conscious about penis size during adolescence, but the vast majority reach a completely normal penis size by the late teen years.


In addition to other physical changes experienced during puberty, such as becoming more muscular and getting taller, this is the time when your penis may become erect in response to becoming sexually aroused, during sleep, or even at unpredictable times. Your testicles begin to grow larger and pubic hair begins to emerge.

The most rapid growth occurs between the ages of 12 and 16. The penis grows in length first and then begins to grow in girth (width). The changes in your penis size can be sudden and fast. You may notice that your body, including your penis, goes through rapid changes for a few weeks, and then remains the same for months before changes begin again.

You will reach your fully developed penis size between the ages of 18 and 21.

In general, your penis may continue to grow for one or two years after you stop growing in height, or four to six years after your testicles enlarge. It's important to know, however, that starting later or earlier is not in any way related to your eventual penis size.

Normal Penis Size

Though men often underestimate the size of their penis because of the angle at which they see it, or misconceptions about how big an average penis measures, chances are good that your own penis is well within the range of most men's sizes. In general, condoms come in sizes that only vary slightly, fitting an erect penis ranging from 7 to about 8 inches in length, and 1.5 to 2 inches in width.

A flaccid penis is much smaller than an erect one, of course. If you are curious about how you compare, you can learn to accurately measure your penis.

How to Measure a Penis
 Verywell / JR Bee

If you can urinate and engage in sexual activity (even of the solo kind) without any problems in functioning, you should not worry.


There are myths about penis size, and young men may hear or spread things that make each other privately worry.

  • Erection ability: The size of your flaccid penis doesn't reflect the size of your erect penis. In many cases, a relatively small flaccid penis can become quite large when erect.
  • Sexual satisfaction: Studies have shown that penis size doesn't actually matter when it comes to sexual satisfaction of either partner.
  • Link between penis size and other body parts: The size of a man's penis is not correlated with the size or development of other body parts, such as hands, feet, facial hair, or baldness, so there is no external or obvious sign that can be used to gauge penis size, function, or abilities.
  • "Manliness": Though a rather stereotypical definition, many associate men with having traits like athleticism and aggression. Penis size is in no way related to one's physical abilities, personality traits, or masculinity.


If you feel that you might be late in going through puberty, or you have concerns that your penis is abnormally small, you should consult with your healthcare provider. There is no need to feel awkward about bringing up the topic.

Your healthcare provider has studied the normal and abnormal aspects of physical development, has heard all types of concerns, and will be able to answer your questions so that you don't have to worry and wonder anymore.

A Word From Verywell

It's not uncommon to feel some anxiety about penis size, particularly during adolescence. But these concerns are usually centered around the above myths.

As you process the facts and become more confident in yourself, concern about your penis (whatever its size) is more likely to become a thing of the past. If you still wish to have a larger penis, it's worth getting all the facts about penile enlargement treatments before moving ahead with any of them.

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  1. Mautz BS, Wong BB, Peters RA, Jennions MD. Penis size interacts with body shape and height to influence male attractiveness. Proc Natl Acad Sci USA. 2013;110(17):6925-30. doi:10.1073/pnas.1219361110

  2. Prause N, Park J, Leung S, Miller G. Women's Preferences for Penis Size: A New Research Method Using Selection among 3D Models. PLoS ONE. 2015;10(9):e0133079. doi:10.1371/journal.pone.0133079

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