A new study conducted by sexuality researchers at Indiana University has found that the average size of an erect penis is 5.57 inches (14.15 centimeters).
In the study, 1,661 men were asked to measure their penis’s length and girth for condom fitting purposes. Dr. Debby Hebernick, co-directer of the Center for Sexual Health Promotion at Indiana University’s School of Public Health-Bloomington, incentivized men to be honest, as she explains on Psychology Today:
Unlike most previous studies of self-reported penis size, [subjects] had good reason to report accurate data to us because we were using their size data to match them to a condom that was sized to fit their erect penis. If they reported a bigger-than-reality size to us, they would get a baggier condom. If they reported a smaller-than-reality size to us, the condom would be too tight.
Not surprisingly, the study found that penises come in all shapes and sizes. The smallest erect penis in the study was about 1.6 inches (4 centimeters) long, and the largest was 10.2 inches (26 centimeters) long. It was also determined that other characteristics of a man, such as his race or orientation, weren’t good predictors of size.
Finally, the study also found that all erections are not created equal. Different methods of obtaining an erection may lead to different size measurements — men in the study who became aroused through oral sex reported larger penis size on average than those who attained erections through fantasizing. “We don’t know if that means that when men have oral sex that it’s more arousing and they get a bigger erection, or means that men who have bigger penises could be getting more oral sex in the first place,” Herbenick said.
I’m 4 inches (10 cm) erect.