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 1825.50
Adult Medium 19.5027
Adult Large 2128
Adult XL 2328.50
Adult 2XL 24.5029
Adult 3XL 22629.50