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 41418
Juvenile 5-61518.50
Juvenile 715.2518.75
Toddler 2T1114.50
Toddler 3T1215.50
Toddler 4T1316.50