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 Small1827
Adult Medium2029.5
Adult Large21.531
Adult XL 2431.5
Adult 2XL25.533
Adult 3XL2833.5