What Is Normal Size and What Does It Mean?

Answer:

Researchers at Kings College London analyzed data from more than 20 studies with more than 15,000 men, who underwent penis size measurements by health professionals using a standardized procedure. The average man’s lengths were 3.61 inches flaccid, 5.17 inches erect; the average circumferences were 3.67 inches flaccid and 4.59 inches erect.

While it’s possible that there are racial differences in penis size, there’s little evidence. Regardless, there’s still a great deal of variation within racial groups, anyway.