Helmet Size

Inches

Centimeters

Hat Size

Small

21.65-22.05

55/56

6 7/8-7

Medium

22.44-22.83

57/58

7 1/8 - ¼

Large

23.23 - 23.62

59/60

7 3/8 - 7 ½

X-Large

24.02

61

7 5/8

XX-Large

25 1/4"

62

7 7/8