What is the average size of a willie?

The average size of an adult human penis varies by studies and populations, but research suggests that the average erect penis size is about 5 to 6 inches (12.7 to 15.2 cm) in length and around 4.5 to 5 inches (11.4 to 12.7 cm) in circumference. It's important to note that individual sizes can vary widely and that these averages do not determine one's worth or abilities.