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 1727.50
Adult Medium 18.5028
Adult Medium - Off-White19.528.5
Adult Large 2030
Adult XL 2331
Adult XL - Off White
Adult 2XL 2531