Silicone CCs in order to go from a small B to full C cup? I'm about 5'3", 120lbs. (Photo)

Something in the 300-3500 cc range should get you into a C cup.  A high profile implant should fit your chest wall nicely.  Again, just a rough guess and best to be fitted by your surgeon prior to surgery.  Best wishes!

At
size 34 B each 100 cc’s of implant corresponds to 1 cup size change.To achieve a C would require 100 cc
implants.I always recommend small round
textured silicone gel implants placed retro-pectoral since they look and feel
more natural, are more stable, less likely to ripple or have complications
needing revision.Implant profile is
irrelevant in the retro-pectoral position since the muscle compresses it.Best Wishes,Gary Horndeski, M.D.

The best cosmetic
result in any particular breast augmentation patient depends on a variety of
factors, including: your individual anatomy, desired result, realistic expectations, a thorough
discussion with the plastic surgeon about the options, and an understanding of
the pros and cons of any particular implant choice. Proper sizing is not just
about the number of cc’s. The thickness of your tissue, breast dimensions which
include the width, height, and projection, as well as chest wall width all need
to be considered when choosing an implant. Trying on implant “sizers” of
various shapes and volumes while wearing a tight t-shirt, bra, or bathing sit
at a preoperative visit will help you and your surgeon choose the optimal
implant.

There are no manufacturers' standards for cup sizing in the bra industry. The
cups of a 34 C and a 38 C are significantly different. Cup size varies from
manufacturer to manufacturer and even within styles from any particular
manufacturer.

Keep in mind that following the advice from a surgeon on this or any other
website who proposes to tell you exactly what to do without examining you,
physically feeling the tissue, assessing your desired outcome, taking a full
medical history, and discussing the pros and cons of each operative procedure
would not be in your best interest. I would suggest you find a plastic surgeon
certified by the American Board of Plastic Surgery and ideally a member of the
American Society for Aesthetic Plastic Surgery (ASAPS) that you trust and are
comfortable with. You should discuss your concerns with that surgeon in
person.

Robert Singer, MD FACS

La Jolla, California

Over the internet we can ONLY guess. I pick a 350 cc UHP. But best to seek IN PERSON opinions from the over 80 boarded PSs in South Florida... 

Thank you for the question and picture. Based on the photograph, you are starting at a good place and should have a very nice outcome with breast augmentation surgery. There is no accurate correlation between size of breast implant and cup size achieved.
Generally speaking, the best online advice I can give to ladies who are considering  breast augmentation surgery ( regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "full C cup”  etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate. Again, best not to discuss your goals and/or judge the outcome of the procedure performed based on achieving a specific cup size.
 The use of computer imaging technology may also be very helpful during this communication process.
3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery. I generally select appropriate breast implant size/profile after the use of temporary intraoperative sizers and viewing the patient's chest in the upright and supine positions.
I hope this (and the attached link) helps.

Thank you for your question.  You have very natural normal pretty breasts and should be an excellent candidate for breast augmentation.In addition because of your normal breast shape and position I suggest that you have a sub-muscular breast augmentation which has less chance of capsular contraction and other problems.Your plastic surgeon certainly should be able to answer your questions about cc of breast implant.This decision should be based on measurements of your breast base width, and a breast implant sizing system evaluation.  During your breast implant sizing specially shaped implants of various cc sizes will be placed into a non-padded bra so that you can look in a mirror  and get an idea of how you will look with that number of cc.Generally speaking it takes 200 cc of breast implants to enlarge you by 1 cup size.  However since you are a small B and want to be a full C  you may well need a breast implant in the 350-450 cc size range.  Again  breast base width measurements and a breast implant sizing evaluation is necessary.If you cannot achieve complete answers with your current plastic surgeon then seek a second opinion from a board certified plastic surgeon who is very experienced in breast augmentation surgery.You have excellent breasts and are an excellent candidate for breast augmentation.  It is crucial that you achieve the result that you want and to help you achieve this goal you need the best, most experienced, board certified plastic surgeon in your area.  The Smart Beauty Guide is a good place to start.For more information on choosing breast implant size please read the following link: