Size guide MEN'S SHIRTS Standard COLLAR (inches) COLLAR (cm) XS S M L XL XXL 14 14 ½ 15 15 ½ 15 ¾ 16 16 ½ 17 17 ½ 17 ¾ 18 36 37 38 39 40 41 42 43 44 45 46 Reiss Philippa Denim Jacket. * Please take a look that this is a guide only and the measurements can be different depends on the brand and style of clothes.