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 1726.5
Adult Medium1930
Adult Large21.531
Adult XL 23.532
Adult 2XL2532.5
Adult 3XL 2735