How big is normal for a man's penis?

Shi Chengli in China once measured the penis size of 1,412 healthy young Chinese men and the erect penis length of 126 healthy men. The results showed that under normal circumstances, the longest was 14.5 cm, the shortest was 4 cm, and the average was 8.375 cm; the maximum circumference was 12 cm, the minimum was 4.5 cm, and the average was 8.3 cm. When erect, the longest is 16 cm, the shortest is 9 cm, and the average is 12 cm; when erect, the circumference is as large as 14 cm, the shortest is 8 cm, and the average is 10.75 cm. The penis lengths of 1,000 normal adult men investigated by Liu Guozhen and Cao Jian were: the normal range was 4.9-8.6 cm, with an average of 6.55 cm, the longest was 10.6 cm, and the shortest was 3.7 cm.

Wu Weicheng et al. measured the penises of 2547 male college students aged 16-40 years old. The average length was 7.43 cm and the average circumference was 8.17 cm. The average penis extension was 13.34 cm, which is similar to the calculated erection length of 13.08 cm. Therefore, it is considered that the extended penis can represent the length after erection. It can be seen that there are certain differences in the measurement results of different authors, and the results are also affected by region, nationality, etc.

In addition, the length of the penis of the same person is not constant under normal circumstances. For example, tension, cold or severe fatigue can cause the penis to shorten. In addition, the measurement methods themselves vary greatly, so it is difficult to judge whether the penis is normal simply by its length.

Therefore, the above figures can only be used as a reference, and you should never compare them with your own length. Clinicians are also reluctant to judge whether a penis is normal based on its length. As long as you can have normal sexual intercourse and complete the task of having children, it is normal. Otherwise, this family would have been eliminated long ago. For example, some people say that white people's penises are long, but not hard enough. In magnetic resonance imaging studies on sexual intercourse, the penises are all bent (like a boomerang). '

In order to further explain the reasons why the penis is large or small, let us review the occurrence and development process of the penis. For the convenience of description, we divide it into four stages:

(1) During the 10th to 12th week of pregnancy, the penis has just been differentiated and is only 3.5 mm long.

(2) During the second and third months of pregnancy, the penis grows rapidly and reaches 2.5-3.5 cm at birth.

(3) From birth to before puberty (around 7 years old), the penis grows slowly.

(4) After puberty begins, the penis grows rapidly and reaches adult size in only about 5 years.

So, what is considered a truly small penis? The penis is considered to be abnormally developed when it is shorter than 2.5 cm before puberty and shorter than 5 cm after puberty, and when the secondary sexual characteristics are underdeveloped, there is sexual dysfunction, infertility, and no sperm. By the way, the method of measuring penis length is very important. One is to measure the flaccid state, and the other is to measure the changes in the erect state. When measuring, the room temperature should be around 25°C. After you calm down and have had a proper rest, lift the penis with your hands, press one end of a hard ruler against the pubic symphysis with a little force to compress the subcutaneous fat layer as much as possible, and use the other end of the ruler as a reference to the external urethral opening of the glans penis. The number read is the normal length of the penis. Then use a tape measure to measure the circumference of the penis shaft 1 cm away from the coronal edge. Because patients are nervous or not used to the environment of the clinic, they often cannot have an erection in front of the doctor, so the stretched length of the penis is often used instead of the erection length.