When the Right Bra Size Still Isn’t Right Not my size. How to find the right bra size. Okay, so you've figured out your bra size using all the rules for measurement and your bra still doesn't feel right. You either get the bunk-bed-boob syndrome (when the bra cuts into the breast, creating the appearance of an extra breast on top of each of your breasts) or your bra straps cut into your shoulders, or your boobs hang out of the bottom or sides of your bra, or something just doesn't feel right. Bra sizes can sometimes vary a lot, depending on the type of bra you're wearing, and even the name brand of the bra. So the best thing to do is go into the dressing room (if possible, try not to go right before your period, when your breasts might be fuller) and try on a bunch of different ones. You might want to ask the salesperson to help you find a particular type of bra: Maybe you want to get a bra with a lot of support, or a minimizer bra. Once you find a bra you like, you might want to jump around a little in the dressing room to see if the bra gives you the support you want, or lean forward in the mirror to see if the cups keep your breasts where you want them to be. It can also be helpful to see what the bra looks like under a T-shirt: Does the lace or any other decoration create weird bulges? Also, by adjusting the length of the straps and the hooks on the back of the bra, you can get a better fit. Wondering how to find the right bra size? Get helpful advice and tips from BeingGirl.