If any of your measurement is on the borderline between two sizes, you can pick the smaller size for a tighter fit or the larger size for a looser

Size  CHEST  LENGTH
in in
X-Small 17.5'' 27''
Small 19'' 28''
Medium 20.5'' 29''
Large 22'' 30''
X-Large 24'' 31''
XX-Large 26'' 32''
XXX-Large 28'' 33''
XXXX-Large 30'' 34''