Ordered in a 2x as I'm a 42F and didn't know what size to purchase.  I might be able to go up a size as the band rolls a little but I would probably lose support in the boob area if I did.  I really like this bra for lounge wear.  It's very comfortable, it doesn't pinch or dig into me. The girls have enough support that I don't feel like I'm going braless.  I'm not sure how long it will last as it is made of the same material that tights are made with, so I don't know how long it will hold it's shape.  It wasn't expensive so when it wears out I'll buy another and try the 3x to see the difference in fit.