Verified by 
A new research study from our Indiana University research team was published online today in the Journal of Sexual Medicine. Its title? Erect Penile Length and Circumference Dimensions of 1,661 Sexually Active Men in the United States. Here’s a bit about our study:
Did we really measure the erect penises of 1,661 men in the US?
No, we did not personally measure men’s penises. Rather, like many studies of penis size, we relied on men to report their penis size.
Were we concerned that men would lie about their size?
Most people are honest—including in sex research studies. Also, men didn’t have any reason to lie to us. In fact, unlike most previous studies of self-reported penis size, they had good reason to report accurate data to us because we were using their size data to match them to a condom that was sized to fit their erect penis. If they reported a bigger-than-reality size to us, they would get a baggier condom. If they reported a smaller-than-reality size to us, the condom would be too tight.
So what did we find?
Well, for people who care about penis size averages (and many people do, based on the questions I receive from readers through Kinsey Confidential and my other work), we found an average erect length of 14.15 cm and an average erect circumference of 12.23 cm as can be seen in the abstract of the article on the Journal of Sexual Medicine’s website. Personally, however, I am more interested in the broad range of penile sizes than only the averages. For those reading the full article, you can find the distribution of reported sizes in Table 3 of our article. There you will note that men in our study had erect penis lengths of 4 to 26 centimeters and erect penis circumferences of 3 to 19 centimeters.
What else interested us?
We also found that reported size varied by how men got the erection that they used for measurement purposes. For example, men who received oral sex as part of the measurement process reported a greater erect length and circumference than did some other men. Is that because oral sex is more arousing to men and thus they have larger erections from it than they do from other sexual behaviors (e.g., self-masturbation with hand or hand stimulation from a partner or fantasy only, etc)? Or are men who have a larger erect penis are more likely to receive oral sex from a partner (or more regularly)? We cannot tell from these data.
What's next?
As a field, I'd like to see more studies that examine women's genitals. There have been numerous studies of penis size and very few studies that examine the size of the female genitals. Though size doesn't matter to everyone, it matters to some people. We have found fairly consistent results for penile dimensions.
But what about women?
Especially given how increasingly common it is to see advertising for female genital cosmetic surgeries, such as labiaplasty, it might help more women to see that there is a wide range of labia size and shape, glans clitoris size and shape, not to mention coloration, etc. (I'm so passionate about helping women to think positively about their genitals that I've been working with a local artist to create a beautiful art poster - based on our scientific research - that shows what women like about their genitals! Check it out here.)
I don't know that I would have ever personally conducted a penis size study, to be honest—it's more that penile size was relevant to the condom study we were conducting (i.e., we need to assess men's penile size in order to provide them with condoms to fit the size of their erect penis) and later thought that others might be interested in the data, particularly because the men would have presumably been motivated to report their penis size accurately in order to receive condoms to fit their penis.
Does size matter?
Research on sexual satisfaction tends to suggest that other factors (such as intimacy, affection, and psychological connection) are more important than a person's genital size. That doesn't mean that genital size is never important to some people, but it does suggest that human qualities—and qualities about how people interact with each other emotionally and psychologically—are among the more important aspects of human sexuality. If you'd like to improve your sexual life with a partner, check out books about sex (I've written a few but so have many other well-respected people), attend a sex-positive workshop if your community offers one, and/or consider sex counseling or therapy. You can also just try talking with your partner to share more about what you'd like to try, how you want to connect, and what you crave in terms of intimacy. Ask your partner what he or she wants and needs from you, too.
If you’d like to learn more about research from our team at the Center for Sexual Health Promotion at Indiana University – including opportunities to participate in future research studies – you can fill out this online form to be added to our mailing list. To receive a copy of the full article from our penis size study, email us at cshp (at) indiana (dot) edu.
Dr. Debby Herbenick is a sex researcher, educator, and author. She is the co-Director of the Center for Sexual Health Promotion at Indiana University School of Public Health-Bloomington and a sexual health educator at The Kinsey Institute for Research in Sex, Gender and Reproduction. Dr. Herbenick is also the author of several books about sex and love.
