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 Small15.5026
Adult Medium18.5028.50
Adult Large2028.50
Adult XL2228.50
Adult 2XL2429
Adult 3XL2629.50