View Current Sweet Protection Helmet Size Chart
 

CM	Helmet Sizes				Inches	Hat Size
53	S/M				20 7/8	6 5/8
54					21 1/4	6 3/4
55					21 5/8	6 7/8
56			M/L		22	7
57					22 3/8	7/18
58					22 3/4	7 1/4
59				L/XL	23 1/4	7 3/8
60					23 5/8	7 1/2
61					24	7 5/8