Posted on March 2, 2018May 16, 2019 by Administrator SM Fitted Hats-S/M, L/XL Measure the circumference around the head, above the eyebrow and at the widest part of the head. Divide number by 3.14 for hat size. S/M L/XL Hat Size 7 – 7 3/8 7 3/8 – 7 3/4 Post navigationPrevious post: SM-One Size Fits All(most)Next post: Charles River Mens Jackets