the 2x was too small in the arms, but fit everywhere else, so I took a chance and ordered the non-prime size 3x (a bit of a blow to my pride, I'm a size 18 - firmly in the one or 2x size group). I get so many compliments on this dress. I usually wear it with a crinoline, but sometimes I don't want to wear that itchy adornment and the dress is cute with out it too.