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 1727.5
Adult Medium 1928
Adult Large2129.5
Adult XL 23.530
Adult 2XL 25.532
Adult 3XL 2631.5