The sizing chart refers to actual body measurements in inches.
Garment measurements are larger to allow 'EASE' of fit. Adult sizes are "unisex" sizes and are a "generous fit".
YOUTH S M L XL
T-Shirt (chest) 26-28" 28-30" 30-32" 32-35"
Pullover Hoodie (chest) 26-28" 28-30" 30-32" 32-34"
Crew Neck Sweatshirt (chest) 26-28" 28-30" 30-32" 32-34"

ADULT XS S M L XL 2XL 3XL 4XL 5XL
Adult T-Shirt (chest) 30-32" 34-36" 38-40" 42-44" 46-48" 50-52" 54-55" 56-57"
Women's T-Shirt (chest) 32-34" 35-36" 37-38" 39-41" 42-44" 45-47" 48-51" 52-55"
Pullover Hoodie (chest) 34-36" 38-40" 37-40" 42-44" 46-48" 50-52" 54-55" 56-57"
Crew Neck Sweatshirt (chest) 36-38" 39-41" 42-44" 45-48" 49-52" 53-56" 57-60" 61-64"