Size (inch)	XS	S	M	L	XL	2XL	3XL	4XL
Width	18	19,3	20,5	21,6	22,8	24	25,2	27,2
Height	26	27	28,5	29	30	30,7	31,5	32,2

To get good measurements, lay the shirt (preferably the one you love) on a flat, hard surface, then if there are any creases, smooth them out as much as possible

Width: place the ruler from the bottom of the sleeve and measure the width stopping under the other sleeve.

Height: measure from the highest point of the shoulder (top of the collar) to the bottom of the shirt.