So how does the regular man size up? The mean length of a flaccid penis is 3.6 inches, and the mean length of an erection is 5.16 inches, according to a paper titled "Am I Normal?" published Tuesday in the British Journal of Urology....If you're keeping score at home, an average guy's erect circumference is 4.59 inches, the researchers found.

Discuss. Or don't. Just don't measure yourself at work.