7 3/8 hat size, 7 5/8 fitted hat, 7 3/4 hat, and a size 8 hat are some of the most common hat sizes for big heads we carry Don't know your head size?. We have made it easy for you to find your head size with a cool tape measure for large heads. ONE SIZE 5460 21 1⁄8 23 1⁄2 6 5⁄8 7 3⁄8 ASOS One size caps are adjustable and have been designed to fit head circumference of between 225 inches (57cm) and 23 inches (59cm) *These charts are for reference only Fit may vary depending on the construction and materials.