Based on information from Score Sports, here are some numbers (in inches) to help you with uniform sizing. Presumably chest size is more relevant for the jersey and waist size for the shorts, but we order jersey and shorts as a unit with a single size. In the Registration, the field you will be required to fill in is labeled as "jersey size".

 

Youth
YXS	YS	YM	YL
26--28	30--32	32--34	34--36
18--20	20--22	22--24	24--26

 

Adult
	AS	AM	AL	AXL
Chest:	36--38	38--40	40--42	44--46
Waist:	28--30	32--34	36--38	40--42