What is the average head circumference of a 4-year-old boy?

The average head circumference for a 4-year-old boy is typically around 49 to 51 centimeters (approximately 19.3 to 20.1 inches). However, individual measurements can vary widely, and factors such as genetics and overall health can influence head size. It's important to consult growth charts and pediatric guidelines for more specific assessments.