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 Small1727.50
Adult Medium 2028.50
Adult Large 2129.50
Adult XL 22.5030.50
Adult 2XL 24.5032