Standard length will be about 2 (give or take) inches under your bust.
Long length will be about 4 (give or take) inches under you bust.
XS : 32" bust
S : 33-33.5" bust
M : 34-35" bust
L : 36-37" bust
XL : 38" bust
2XL : 39-40" bust
3XL : 41-42" bust
4XL : 43-44" bust