How Many CCs to Reach a Full C?

It is difficult to determine exact cup size post-operatively. Every manufacturer produces a variety of bra styles, which may differ in size and shape. Clear communication with your plastic surgeon is important in achieving the desired goals of the patient.  I like to communicate with patients with “goal” pictures.  During surgery, I use temporary sizers to determine the size/profile that will give the patient the look she is looking for. Trying to predict the size of the implant preoperatively is not ideal.  I think it is too much responsibility for the patient to choose the size of the implant.  Ideally, the surgeon would make that determination once he/she is in the operating room with sizers in and examining the patient in the upright and supine position.  There are many variables that come into play when choosing the correct implant size (how much breast tissue the patient currently has, the shape of the chest wall (concave vs. convex), etc..

On this site, I do my best to give advice without a physical examination but I want you to know that a physical examination by a board certified physician is always the best way to get the most accurate information.
 

It is hard to predict a bra size after breast augmentation.  Depending on brand, style, and shape, the cup size often varies.  With 300cc implant volume, you may be full C, possibly small D.  Wait on buying new bras for 3-4 weeks.

Without a posted photos very hard to advise. But my guess is a 300 cc will make you a small C cup. I think a 375 to 400 cc HP would have been a wiser choice, just my opinion.