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 Navy1828.5
Adult Medium - Light Navy2028.5
Adult Large - Light Navy2229
Adult XL - Light Navy2430.5
Adult 2XL - Light Navy2531