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 - Off White1728
Adult Medium - Off White1929
Adult Large - Off White2129.5
Adult XL - Off White2330.5
Adult 2XL - Off White2531.5