I had spent the best part of an hour reading reviews and had noted that some women thought the bra was a little on the tight side where the back size is concerned, so before purchasing this bra, I actually went into a department store to try it on before hand. I am usually a 36DD, so this was the size I tried. The back size was perfect. It was easily fasten at the front and twisted round quite comfortably, yet it was tight enough to stay in place. What I did find however, was that the cup was a little on the big side. I didn't bother to try on a 36D, I went straight home and ordered it on Amazon for £14 less (bargain)! The bra arrived and fitted perfectly! What a result. It is incredibly comfortable, I don't find that it digs in (again, an issue for other women) and the cleavage in the bra is fantastic. I don't think I have ever come across a strapless bra as amazing as this one to be honest. If you are going to buy this bra online without trying it on before hand, through personal experience I would suggest purchasing it in your normal backsize, but one cup size less. If you can do what I did though, try it on in store first!