Please measure one of your Favorite T-Shirt at home from Armpit to Armpit before purchasing.

US Medium Armpit to Armpit 20.7" Inches / 52.5 cms

US Large Armpit to Armpit 21.5" Inches / 54.5 cms

US X-Large Armpit to Armpit 22.3" Inches / 56.5 cms

US 2X-Large Armpit to Armpit 23.1" Inches / 58.5 cms