Most data studies show that the static length of the penis of adult males is about 5 to 7cm, and the length in the erect state is about 10 to 15cm, and the average may be around 11cm. However, the length of the penis of each adult male is different due to factors such as genetic factors, acquired developmental factors, excessive masturbation during puberty as well as phimosis and so on, and it can’t be generalized. The length of the penis is around 2.5cm when a baby boy is born, and the growth rate is relatively slow in the following two years, which can be around 0.5cm, and at the age of 2 to 11 years old, the length will only increase by around 0.2cm per year. After puberty, the growth rate may accelerate rapidly and can reach adult levels in about 5 to 6 years. There is basically no uniform standard for the length and size of the developing penis, but most studies have shown that the static length of the adult male penis is about 5-7cm, and the length in the erect state is about 10-15cm, with an average of about 11cm. However, if the length of adult male penis is less than 4.5cm in resting state or less than 7.5cm in erect state, it will be regarded as short penis. If you find that the development of male penis is significantly smaller than that of your peers, it is recommended that you seek medical treatment as soon as possible.