HEAD CIRCUMFERENCE
(inches) 
HELMET SIZE 
HAT SIZE 
HEAD CIRCUMFERENCE
(metric)
19 3/4 - 20 1/8 Child S/M  6 1/4 - 6 1/2 50 - 52
21 1/4  Child L/XL  6 5/8 - 6 3/4 53 - 54
21 1/8  XXS Small 6 3/8 - 6 1/2 51 - 52
21 1/4  XS Small  6 5/8 - 6 3/4 53 - 54
21 5/8  Small 6 7/8 - 7 55 - 56
22 3/8  Medium 7 1/8 - 7 1/4 57 - 58
23 1/8  Large 7 3/8 - 7 1/2 59 - 60
23 1/2  X Large 7 5/8 - 7 3/4 61 - 62
24 1/4  XX Large 7 7/8 - 8 63 - 64
24 5/8  XXX Large 8 3/8 - 8 1/2
65 - 66