Sizing is messed up! I'm 6'1” tall, 203lbs, with a 42.5” chest, 37” natural waist, and 34.5” sleeve length (dress shirt measurement). So, I follow the size chart for the Chore Coat,
Size Chart for Carhartt CT103828 Duck Detroit Jacket - A2ZClothing.com
Carhartt Men's Sandstone Active Jacket,Carhartt Brown,Small at Amazon Men's Clothing store: Work Utility Outerwear