Note : It is recommended to measure your chest with an inch tape first and then choose size so there is no confusion regarding the same.
Slim Fit : The Shirt will be on an average 4 Inch loose from the body, it will give you a perfect slim fit experience.
Relaxed Fit: The shirt will be on an average 6 Inches loose from your body. It will give you a sense of comfortable fit.
Choose according to your preference.
Note : Slim Fit is always recommended.