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 18.5027
Adult Medium 19.7527.50
Adult Large 2129
Adult XL 2429.50
Adult 2XL25.7531