Penis length measurements include both erect and non-erect measurements with a straightedge. Regardless of whether it is measured with or without erection, the specific measurement of penis length is to hold a straightedge against the pubic symphysis above the penis and keep the penis parallel to the straightedge, then measure the distance from the pubic symphysis to the tip of the head of the penis, that is, the length of the penis. The average length of male penis is 4~8cm in natural state and 10~13cm in erect state, if the male penis is less than 4cm in soft state and 8cm in erect state, the penis is considered short. Short penis may cause physiological harm to men, and such patients are advised to actively seek medical treatment. Other than that, normal penis length has no significant effect on the human body, and men are advised not to be too concerned about penis length.