Will 300cc Implants Take a B to a D Cup?

I would try a 300 cc sizer on and then wear different bras to assess and predict the final cup size. There is no definitive method of predicting your final cup size but these methods do allow you to estimate.

Really difficult to say as there are no pictures for us to look at.  Also would need to see measurements as well.  If you truly are a 36B then a 300 cc implant may not get you what you are looking for.

I would not be fixated on size, I am not sure how you came up with the 300 cc size, but I would recommend seeing a board certified plastic surgeon that is knowledgable in the procedure.

Good luck.

300cc seems a bit small to go from a B to a D cup.  In order to make an accurate size recommendation, I would need to assess your chest wall and breast mound measurements and characteristics.  Unfortunately, there is not a general rule of thumb or objective criteria to implant selection.

Your plastic surgeon will perform several measurements of your chest wall and breast anatomy and determine a range of implants that both fit your chest wall and reach your desired goals.
The next step is to try on this range of implants in the office with your doctor.   The key to this success is showing your surgeon the body proportion you desire with a bra sizer and allowing your surgeon to guide you to the right implant.   It will be much easier to communicate in implant cc's than cup size when determining the appropriate implant for you.
I wish you a safe recovery and fantastic result.
Dr. Gill