Width is measured across the chest below the sleeves from seam to seam. Height is measured from the bottom of the shirt to the highest point on the shoulder (where the seam meets the neck).

Please note that each product has its own specific sizing chart.
SizeWidth (inches)Height (inches)
Adult Small 17.526.5
Adult Medium2028.5
Adult Large21.531
Adult XL2332
Adult 2XL 2633
Adult 3XL 27.533