Penis length varies from age to age. Pre-pubertal lengths can range from 4cm-7cm and adult lengths can be around 13cm, all of which are stretched lengths. The average penis length at age 1 is 4.0cm, at age 2 is 4.6cm, at age 3 is 5cm, and from age 7 to pre-pubescent is 7cm, with a diameter of 1cm-2.7cm.The penis grows faster at puberty, with an average erectile length of 13cm, with a diameter of 2.24cm-3cm.There is no strict clinical size for the penis, as it can be around 13cm in adult life. Clinically there is no strict penis size, because the size of the penis is affected by different races, genetics and other factors. It is mostly individualized. Studies have found that people with long and thin body types have large penises, and people with short and fat body types have small penises.