Measure your bust around the largest part of your chest and your waist around the slimmest part of your waist.

Size Bust (in) Waist (in)
XS 30 - 33.5 25 - 27
S 33.5 - 36 27 - 29
M 36 - 38 29 - 31
L 38 - 41 31 - 34
XL 41 - 44 34 - 37
2X 44 - 47 37 - 40
3X 47 - 50  40 - 43