All size measurements are in inches, unless otherwise noted.

Boys’ Activewear Size Chart

Size Chest Waist Seat Height
XS 4 22 21 23 39
5 23 21.5 24 44
S 6 24 22 25 45
7 24.75 22.5 25.75 48.5
M 8 26.25 23.25 26.5 50
L 10 28 24.25 28 54
12 29.5 25.25 30 58
XL 14 31 26.5 32 61
16 32.5 27.5 34 64
2XL 18 34 28.5 35.5 66

Boys’ Undershirts Size Chart

Size Height Chest
2T/3T 27 - 34 34 - 38
4T 35 - 38 39 - 42
S 2 34 21
4 40 23
M 6 41 24
8 50 26
L 10 51 27
12 58 29
XL 14 59 30
16 64 32

Boys’ Underwear Size Chart

Size Weight (lbs) Waist
2T/3T 27 - 34 20.5
4T 35 - 38 21.5
XS 2 27 20
4 41 22
S 6 42 22
8 56 24
M 10 57 24
12 89 26
L 14 90 26
16 118 28
XL 18 119 28
20 138 30