‘What’s the Average Size of a Man’s Johnson?’ — Ask Dr. Harry Fisch

"How big is the average penis?"

The average length of an erect penis is a little more than 5 inches long. Of course there’s variation.

On the small side of things, a guy is considered normal if his erect penis is at least 3 inches long. And some men have longer-than-average penises. In his book 'Penis Size and Enlargement: Facts, Fallacies, and Proven Methods,' Garry Griffin found about 15 percent of men have a penis longer than 7 inches when erect; 3 percent of men are bigger than 8 inches when erect; and one man in 10,000 has a 10-inch erection.

But remember: longer is not necessarily better. In fact, a longer-than-normal erect penis may cause a woman pain during sex because the tip of the penis hits the woman’s cervix.

Dr. Harry Fisch is a board certified urologist at New York Presbyterian Hospital/Weill Medical College of Cornell University. Each week, he’ll answer reader questions in an effort to get guys to ‘man up about health.’