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 XL 23.530.5
Adult 2XL 25.530.5
Adult Small 1725.5
Adult Medium 19.528
Adult Large 2228