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 Small17.526.5
Adult Medium 1929
Adult Large20.530
Adult XL 2231.5
Adult 2XL 24.532
Adult 3XL26.533