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 Small1824.50
Adult Medium19.5027
Adult Large2028.50
Adult XL22.5029
Adult 2XL23.5029.50
Adult 3XL24.5030