Best way to assess sizing: Grab your current favorite Tee from your closet and measure the width at one inch below the armpit. Check the size chart below and make your decision. 

Unisex Lightweight Tee: 

Inches Width Length
XS 16.5 27
S 18 28
M 20 29
L 22 30
XL 24 31
2XL 26 32
3XL 28 33

Long Sleeved Hoodie Tee: 

Inches Width Length
S 18 28
M 20 29
L 22 30
XL 24 31
2XL 26 32
3XL 28 33

Sweatshirt Hoodie: 

Inches Width Length
XS 20.5 27
S 22 28
M 23.5 29
L 25 30
XL 26.5 31
2XL 28 32
3XL 30 32.5