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 - Red Heather1725
Adult Medium - Red Heather18.527
Adult Large - Red Heather20.527
Adult XL - Red Heather2230.5
Adult 2XL - Red Heather2629.5