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 1827
Adult Medium 19.529.5
Adult Large 21.529
Adult XL 24.530
Adult Medium - Kelly Green1827.5