Yes, you can go down to a C cup with a breast reduction, but it may or may not look good on you. How small you can be is really not the question, because a surgeon can remove all of your breast tissue entirely. What really matters is how small you can be while maintaining a pleasing breast shape that is in proportion to your body. Your overall height and body shape influence how different breast sizes and shapes look on your body. There are many factors your surgeon will take into account to give you a shape and size that suit your body. There is a balance to maintain in order to end up with nice looking breasts, and includes breast size, shape, cup volume, nipple position, symmetry, chest width, torso height, etc. If you are told an expected cup size after surgery, keep in mind that is only a guess. Most surgeons do not speak in terms of cup sizes because your cup size will vary based on what brand lingerie you buy. Also, when patients describe what cup size they want, they are not just referring to the breast volume they like, but the shape that they like when the breasts are in a bra. When the breasts are reduced, the relative proportions of the breasts, stomach, hips, etc all change. It's not just the breasts that appear different after surgery. When a large volume is reduced, some patients feel like their stomach looks bigger, or their hips look wider, or their back fat has increased, etc. It's not that the surgeon touched the stomach or hips or back, but now the breasts are smaller so all of the proportions look different. In larger women, from a side view the stomach could even stick out more than the breasts, because the breasts no longer droop over the stomach. Patients are not expected to know all of these things, but your surgeon should be aware of all of the considerations. If you have really large breasts sometimes the nipple could be at risk for losing some blood supply, and the technique of breast reduction is important in keeping the nipples alive. I would recommend consulting with a board certified plastic surgeon to see what is a reasonable size reduction for you. Good luck!