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)
Toddler 2T - Kelly Green11.514.5
Toddler 3T - Kelly Green1216
Toddler 4T - Kelly Green1317