Measure your sleeve and chest based on the directions below for a perfect fit.
Sleeve: For accurate measuring, start at the back and center (nape) of your neck, down to your shoulder, then to your elbow, and finally, ending at your wrist where the edge of the cuff would be. Don't forget you'll want a small bit of shirt sleeve showing beyond your jacket sleeve.
Chest: Standing upright, have someone measure around your chest. Make sure the measuring tape crosses your shoulder blades, around the fullest part of your chest. Tape measure should be snug and not too light.