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 - Oxford Grey17.527.5
Adult Medium - Oxford Grey1929
Adult Large - Oxford Grey2130
Adult XL - Oxford Grey23.531