I'd ordered a size 6 & 10 (as the back up). I normally wear an 8, but I've lost some weight and have been in between a 6 and 8. The size 6 wouldn't zip completely. So thank the LORD for the backupI They didn't have an 8 so I had to go with a 10, and I'm glad I did! The tightest part of the dress is right where the belt ties, and about 3 inches higher. So it was difficult to get over my chest. BUT, once it was zipped.. It was STUNNING! Very flowy! I hated sending this dress back!