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)
Juvenile 413.5017
Juvenile 5-61419
Juvenile 71619.50
Toddler 2T - Navy Blue11.514
Toddler 3T - Navy Blue12.515.5
Toddler 4T13.5016