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 - All Over Print1826.5
Adult Medium - All Over Print1927
Adult Large - All Over Print2128
Adult XL - All Over Print22.529
Adult 2XL - All Over Print24.528.5