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)
Adult Small - Bright Yellow1826.5
Adult Medium - Bright Yellow19.529
Adult Large - Bright Yellow2229
Adult XL - Bright Yellow2430
Adult 2XL - Bright Yellow25.531.5