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 Medium - Brown Heather19.527
Adult Large - Brown Heather2129
Adult XL - Brown Heather23.529.5
Adult 2XL - Brown Heather25.531