The tag says it is a size 11 but the measurements are a bit smaller then an 11 that is why I placed a 6-7 petite on it because that was the size I was wearing at the time I had tried on this dress a long while back. (im no where near that size now lol)
When I placed it on the dummy in the photo to the smallest setting 39 bust and 30 waist. it zipped up great till the top 3 inches then i could barely zip all the way up so i know that the bust is a bit smaller then 39 and the waist is about 30-32 I just did it again to be sure the measurements for you and i would say that the bust is about 36-38 and the waist is about 30-32