I ordered US12, which is labeled 4x in china and on the shirt's tag.  I usually wear a size 10 or 12, depending on the manufacturer.  My bra size is 38B and there is no room for my girls.  Now, grated, I do wear a padded bra, so maybe someone else with that size might fit better.  If you wear a bigger bra size, you might not fit.  There is stretch in the shirt and I'm hoping to stretch it out after the wash and let it air dry, because the shirt pulls and I can see in my shirt where there isn't a button.  I wish there wasn't any stretch and it was made bigger.  Other than that, it is a nice shirt, I'm just disappointed that I can't wear it and that there aren't bigger sizes. I wish there were more blouses with a body suit sewed in, so that they fit better and don't get untucked when crouching down.  BTW - always read the 1, 2, and 3 star reviews, because I feel like Amazon is not trustworthy anymore and that reviews are padded with fake 4 and 5 star reviews.