Whats the average bicep circumference for an eighteen year old?

According to the American Council on Exercise (ACE), the average bicep circumference for an 18-year-old male is 13.5 inches (34.3 centimeters). The average bicep circumference for an 18-year-old female is 11.5 inches (29.2 centimeters).

It's important to note that these are just averages, and individual bicep circumferences can vary significantly depending on factors such as genetics, physical activity, and body composition.