Measure By Size By Inch By Centimeter Age
XXS   6 18 3/4 48 Infant
XXS   6 1/8 19 1/8 49 Infant
XXS   6 1/4 19 1/2 50 Infant
XS   6 3/8 20 51 Toddler
XS   6 1/2 20 3/8 52 Toddler
XS XS/S 6 5/8 20 3/4 53 Toddler
S XS/S 6 3/4 21 1/8 54 Child/Adult
S S/M 6 7/8 21 1/2 55 Child/Adult
M S/M 7 22 56 Adult
M M/L 7 1/8 22 3/8 57 Adult
L   7 1/4 22 3/4 58 Adult
L L/XL 7 3/8 23 1/8 59 Adult
XL XL/2XL 7 1/2 23 1/2 60 Adult
XL XL/2XL 7 5/8 24 61 Adult
XXL XL/2XL 7 3/4 24 3/8 62 Adult
XXL   7 7/8 24 3/4 63 Adult
XXL 2XL/3XL 8 25 1/8 64 Adult
XXXL 2XL/3XL 8 1/8 25 1/2 65 Adult
XXXL 2XL/3XL 8 1/4 26 66 Adult
XXXL   8 3/8 26 3/8 67 Adult