How to Measure a Shirt: Short Sleeve Opening
The short sleeve opening width is measured along the bottom edge of the sleeve opening. Start with the shirt buttoned up fully, facing up. On a firm, flat surface, spread the shirt sleeve out such that the opening of the sleeve is perfectly flat and the front and back edges are straight and aligned over each other. Run your hands across the sleeve in a spreading motion to be sure there are no wrinkles underneath. The starting point of this measurement is at the bottom corner of the sleeve opening. Place one end of the measuring tape at this point. Run the measuring tape along the edge of the sleeve opening to the top corner. Measure to the top edge of the sleeve. Round up to the nearest ¼ inch.