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 - Navy Heather1827
Adult Medium - Navy Heather20.528.5
Adult Large - Navy Heather2129.5
Adult XL - Navy Heather23.530
Adult 2XL - Navy Heather2530.5