How big is the average penis?

There is tremendous variability regarding the size of the flaccid or non-erect penis. Flaccid penile length is a poor predictor of erectile length. The average erect human penis is approximately 5-6.2 inches (12.7-16 cm). Research studies that rely of self-measurement will report higher than average lengths compared to those measurements made by an investigative staff member. An adult human penis with an erect length of less than 2.8 inches (7cm) but otherwise “normal” in appearance is medically considered to be a micropenis.

When it comes to penis size, there are generally two meaningful dimensions. The first is penis length, the measurement from the base of a man's penis (usually close to where his pubic hair begins) to the tip (where the urethra opens at the end of the glans).

The second dimension is girth, which is the distance around a penis (the circumference), usually measured at the middle of a man's penile shaft. The review of studies in BJU International found that, in a sample of more than 11,500 men, the average penis ranged in length between 5.5 and 6.2 inches and between 4.7 and 5.1 inches in girth. That's in line with the results of a survey by LifeStyle Condoms, which put the average penis size at 5.9 inches long and about 4.9 inches wide.

These measurements refer to the erect penis -- the size of a flaccid penis has little to do with the size of an erection: Some men with small flaccid penises (sometimes jokingly called "growers, not showers") can get much larger when hard; others aren't noticeably bigger.