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 Small1726
Adult Medium18.5026
Adult Large - Red19.7527.50
Adult XL22.5030
Adult 2XL2432
Adult 3XL25.5034