Over 15,000 penises have been measured in hopes of bringing men some final peace of mind that whatever you are packing is normal. This vast collection of penile length and girth is not a small result of a larger study, but instead a compendium of 20 studies of penis sizes. "There's nothing fantastic about it, it's a very simple study," says David Veale, a consultant psychiatrist at Maudsley Hospital and lead author of the study.

This research brought together 15,521 penises from men who were ages 17 or over. All measurements had to be done by a health professional. These men could not be suffering from erectile dysfunction or be complaining of small penis size — something that experts note may have skewed the results. Furthermore, not every study contained numbers for each measurement. There were fewer measurements available for erect length and circumference, as well as flaccid circumference.

Still, the results were clear: All together, the numbers showed that the mean length of a flaccid penis is 3.6 inches and the mean length of an erect penis is 5.16 inches. It found that the average girth is 3.7 inches when flaccid and 4.6 inches when erect. The study also found very little evidence that penile length relates to finger ratio, testicle size, age, or foot size. Four of the studies did show a significant relationship between stretched length and erect length.

Overall, these numbers fall in line with previously reported averages from other research, which makes sense, considering this is a collection of past studies. Even though it reaffirms what seems to have been established, the hope for this work is that it can have a positive impact. "It's a bit of a jokey subject, but it is something some men are very worried about, very ashamed about. So, it's important," says Veale. Preoccupation with penis size can range from passing concern (which Veale says can usually be fairly easily addressed) to rare cases where the concern is distracting and debilitating, a form of body dismorphic disorder (BDD). BDD often requires more elaborate treatment, which can involve cognitive behavioral therapy and medication. 

Looking up average penis size prior to this study gave much the same results as Veale and his colleagues reported but, for those who didn't get the reassurance they needed from the Internet, here are 15,521 penises from around the world sending one, encouraging message: You are normal.