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) - Black
Youth Small (6-8) - Oxford Grey1520
Youth Medium (10-12) - Black1823
Youth Medium (10-12) - Oxford Grey1723
Youth Large (14-16) - Black1824
Youth Large (14-16) - Oxford Grey17.524
Youth Large (14-16) - Silver1824
Youth XL (18-20) - Black1925.5
Youth XL (18-20) - Oxford Grey18.527
Youth XL (18-20) - Silver19.525.5