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) - Royal Blue13.520
Youth Medium (10-12) - Royal Blue1621.5
Youth Large (14-16) - Royal Blue17.523
Youth XL (18-20) - Royal Blue1925.5