Normally a man’s penis is 4.5 to 11 centimeters when it is not erect and 10.7 to 16.5 centimeters when it is erect. Men’s penises can usually be categorized into two states: non-erect and erect, and the exact length of the penis may vary due to the individual’s physical condition and hormone secretion level. The penis is usually around 4.5 to 11 centimeters when it is not erect, and when it is erect the penis can be twice as long as when it is not erect, usually around 10.7 to 16.5 centimeters. Men whose penis size is not up to par, but does not interfere with their sex life or fertility, usually do not need treatment. It is recommended that men try to keep a relaxed mood and avoid stress in their lives, as well as pay attention to the cleanliness of the penis. If a man has a short penis and it affects his sex life, he is advised to go to a regular hospital for examination as soon as possible and under the guidance of a doctor for treatment.