The average penis size varies slightly depending on the study, but most studies estimate the average to be within the range of 5.1 to 5.5 inches (12.95-13.97 cm) when erect. The average length of a flaccid penis is around 3.61 inches (9.16 cm) . It is important to note that penis size varies widely and falls within a normal range. Many men wish their penises were larger when in reality they have normal-sized penises. It is also worth noting that penis enlargement methods exist, but many may be harmful, do not work, or only have temporary effects.