To determine your head size, snugly wrap a tailor (flexible) measuring tape around the head just above the eyebrows and the ears. Select the larger size if the result is in between sizes.

U.S.MetricInches
6 1/25220 3/4
6 5/85320 7/8
6 3/45421 1/8
6 7/85521 1/2
75621 7/8
7 1/85722 1/4
7 1/45822 5/8
7 3/85923
7 1/26023 1/2
7 5/86123 7/8
7 3/46224 1/4
7 7/86324 5/8
86425 1/4