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 - Gray Heather1727.5
Adult Medium - Gray Heather1929
Adult Large - Gray Heather2129.5
Adult XL - Gray Heather2331