Size chart for Men

Active-X Low Cut

US Men US Youth Euro SOCK SIZE
4-5 Y4–Y5 36-37.5 S
5.5-7 38-40 M
7.5-9 40.5-42.5 L
9.5-10.5 43-44.5 XL
11-12 45-46.5 XXL

(If you are between sizes, size up.)

Active-X Mid & High Cut

US Men US Youth Euro SOCK SIZE
Y2–Y3 33.5-35 XS
3.5-5.5 Y3.5–Y5.5 35.5-38 S
6-8 38.5-41 M
8.5-10 41.5-44 L
10.5-12 44.5-46.5 XL
12.5-13.5 47-48.5 XXL

(If you are between sizes, size up.)

Secret 3.0 Low, Mid, & High Cut

US Men US Youth Euro SOCK SIZE
4-5.5 Y4–Y5.5 36-38 S
6-8 38.5-41 M
8.5-10.5 41.5-44.5 L
11-12.5 45-47 XL

(If you are between sizes, size up.)