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 - Kelly Green17.528
Adult Medium - Kelly Green19.529
Adult Large - Kelly Green21.530
Adult XL - Kelly Green2430.5
Adult 2XL - Kelly Green24.530.5