If the cups of your bra curl out on the top edges, your cup size is too small.
If the band is not level all the way around, your cup size is too small or your band size is too big. (Or your straps could be too tight!)
If your skin bulges out around the band of your bra, it could mean two things: either the band size is too small, or the band needs to be wider.
There are two reasons that proper fit is so important:
1. If your bra doesn’t fit correctly then your breasts aren’t getting the support they need. This can be bad for your breasts(because breasts ligaments never regain their perkiness) and it can be bad for your back if your girls are of the larger variety.
2. If your bra doesn’t fit you properly, your clothes might not be as flattering as they could be for you.