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 - Light Blue18.527
Adult Medium - Light Blue18.527.5
Adult Large - Light Blue2229
Adult XL - Light Blue2430.5
Adult 2XL - Light Blue25.531