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)
Youth Small (6-8) - Faded Yellow1620
Youth Medium (10-12) - Faded Yellow16.522
Youth Large (14-16) - Faded Yellow17.523.5
Youth XS (2-4) - Faded Yellow1418