This is an "easy to fit" piece considering it's made of a stretchy elastic that wraps around your bust & back. This makes it hard to provide accurate bust measurements. The measurements below are of the "non-stretchy" parts of the dress.
Order your true hj top size, unless your pant size is 2 sizes or + bigger than your top size, in that case size up one size. (I.e if top is XS and pants L, go with the S)