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 - Green Heather1827.5
Adult Medium - Green Heather19.526
Adult Large - Green Heather2128.5
Adult XL - Green Heather23.530