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 - All Over Print16.525
Adult Medium - All Over Print18.526.5
Adult Large - All Over Print20.528
Adult XL - All Over Print21.528
Adult 2XL - All Over Print2428