According to 2010 data collected by the Centers for Disease Control, the average waist size for an adult male over 20 years old is 39.7 inches. The average height is 5 feet 8 inches, and the average weight is 195.5 pounds.
The top-selling pant waist size in the United States, as of 2014, is a size 34. The disparity between this number and actual waist size averages is explained in part by "vanity sizing," in which the actual size of the pant is different from the size advertised. When vanity sizing is used, waist measurements are usually 1 1/2 to 2 inches larger than those stated on the tag.