A well-fitting bra is essential for comfort and support. We recommend getting a professional fitting or at least finding a bra size chart and measuring yourself at home. However, slight sizing variations between manufacturers can leave you with an ill-fitting bra even if you bought it in your size. That's why it's important to know what to check for to see if your bra doesn't fit correctly.;Saggy cups indicate the cup size of your bra is too large. If your breasts spill out from the sides or top of the cup, the cup size is too small. When the back of your bra sits higher than your natural underbust line, even with the shoulder straps adjusted correctly, the band size of your bras is too small. A loose and unsupportive band, even on the smallest clasp, means your band size is too large.