Average is about 5 to 5 1/2"
You might think that as long a man's penis works, he would have no problem with it. You would be wrong.
Penis size is a key element of a man's self-image. Yet when he's not boasting to other men, the average man significantly underestimates the relative size of his penis.
Here's an example: Over a two-year period, 67 men asked an Italian hospital for surgical correction of a small penis. All turned out to have normal-size penises.
"A few days ago, I had a patient who spent an hour taking measurements of his penis and thinking it is too small," Gilbert says. "Yet it was normal."
That man isn't alone. About 45% of his brethren want a bigger penis. Never mind that 85% of heterosexual women say they are satisfied with their partners' penis parameters.
Many men worry about the size of their erections. Many more worry about how their penis looks when it's limp, studies find.
So how can a man know if he's normal, super-sized, or small? Not by his shoe size, a common and disproved myth about estimating penis length. Like so much else in life, direct measurement is the key.
How to Measure a Penis
Men may be surprised to learn that penis length isn't measured on the erect penis. Too many variables are involved.
Instead, the most reliable penis measurement is called SPL -- stretched penis length. The longer a man's SPL, the longer his erect penis length, according to studies done on brave young men who volunteered to have erection-stimulating penis injections.
To learn your SPL, measure the penis while it's flaccid. Press the ruler tight against the pubic bone at the base of the penis. Don't just measure from where the penis separates from the scrotum, or you'll lose precious centimeters. Now gently, but very firmly, stretch the penis as far as it will go. Measure from the pubic bone to the tip of the stretched penis.