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 Medium - All Over Print2128.5
Adult Large - All Over Print2328
Adult XL - All Over Print24.528.5
Adult 2XL - All Over Print26.528.5