I'm 5' 7 & 250lbs  Wear a size 18 bottom and usually 1x top.  I ordered this dress in the XXL size  And was surprised to see it a little loose ( As big girls know we order something and it usually fits like a size medium from Amazon)  I could have possibly went down a smaller size but I'm not ordering one to find out lol the XXL size fits beautifully and the dress is meant to be loose fitting, all I do is add a nice belt and it is an adorable daytime outfit  Don't think about it,  just buy it you will love it