Is 500cc too large on 5ft 3 inch 118lb?

It is very difficult without assessing you in person to know what implant size will be a good size for you. Keep in mind that implant size selection not only depends on your personal preference, but it also depends on your unique measurements. There are various types of implants that can help you attain the look you are going for. A thorough consultation with a board certified plastic surgeon will allow you to communicate what your desired result is and will inform you as to what is possible to achieve your goals and determine if a lift is necessary. There are various factors that need to be considered when deciding whether or not you need a lift. We have a device called the Vectra 3D imaging system that shows you what you will look like with any implant with or without the lift. Our patients are very happy with the choice of implant they make when using this system. To learn more about breast augmentation, you can read “A Comprehensive Guide to Breast Augmentation.”

The best option for your body and aesthetic goals can be determined in a thorough implant sizing session.
Implant sizing depends on several factors. One of the most important factors is your breast width. Generally, your surgeon will measure your breast width, and then provide you with a range of implant sizes appropriate for your native breast size. There are more nuances to it than just what I've described, but this approach works for most women.
I usually have my patients bring in a large bra and a tight t-shirt to do sizing. I'll then choose 3-4 implants that I feel are appropriate, and have my patients place them in the bra under the tight t-shirt. My patients can then look in the mirror and get a good sense of what they will look like with the provided implant sizes. My patients like this approach and get a great idea of how they will look.
By using this technique, your surgeon can outline a range of appropriate implant sizes that will be aesthetically pleasing, and you make the final decision.
I hope this helps. Good luck!
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500
cc implants weight over 1 lb each and will not fit sub-muscular.  You describe your breasts as sagging so you
would benefit from a lift.  An
alternative would be The Bellesoma Method. 
This will reshape your breast tissue creating upper pole fullness
without implants, elevate them higher on the chest wall and more medial to
increase your cleavage.  Vertical scars
are avoided, nipple sensation and the ability to breast feed are maintained.  At the same time or later, fat transfers can
be performed if additional volume is desired.Best Wishes,Gary Horndeski, M.D.

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation.  The size, profile, and shape of the
implant is based on your desired breast size/shape, your chest wall
measurements, and soft tissue quality.  This decision should
be based on a detailed discussion with equal input from both you
and your surgeon.   Make sure you specifically look
at before and after pictures of real patients who have had this surgery
performed by your surgeon and evaluate their results.   The most
important aspect is to find a surgeon you are comfortable with. I recommend
that you seek consultation with a qualified board-certified plastic surgeon who
can evaluate you in person.
Best wishes and good luck.
Richard G. Reish, M.D.  FACS
Harvard-trained plastic surgeon

Patients often think in terms of cup size when considering augmentation. Unfortunately, devices are sized in terms of milliliters (cc) of volume. This can lead to some confusion when sizing. Additionally, it is important to remember that cup size itself is not standardized with variations from one manufacturer to another. Unfortunately, as many women can attest their cup size in an industry leader such as VS is not necessarily transferable to another brand.
Another point which is often under appreciated is that of anatomy and starting point. Any implant will add volume to the volume which is already present. The implant is additive. A particular volume will not necessarily confer the same cup size to different patients (often times it will not even confer the same cup size to different breasts in the same individual...remember they are "sisters" not "twins"). 
A general rule of thumb is that 125cc can represent somewhere between 1/2 to a full cup size increase. Smaller volume differentials (25-50cc) are typically less consequential representing a volume change of less than a shot glass. However, I have found these numbers, at least anecdotally, to be of little help. Patients often present with notions/goals which do not correlate with these sorts of sterile volumetric assessments.
When sizing patients, there are a number of useful tools including:
-3D imaging (has the added benefit of offering a volumetric analysis of the pre-operative breast)
-Breast sizers (rice bags)
-Goal photos
I also recommend that patients commit to a particular look rather than a cup size. Once a patient settles on a look that pleases them the overall cup size increase becomes less relevant.The key to obtaining a natural result is to stay within the parameters defined by your BWD. This will ensure that you avoid the dreaded "fake" look. 
With regards to your specific question, "too big" is a personal question based upon expectations and goals. As long as you have been sized appropriately and are staying within the parameters as defined by your BWD you should get a reasonable result. 500 cc is a larger implant. However, without photos or measures it is difficult to say. At 5'3" and 118 lbs, this may be a larger implant. If there is no concern for a "natural" result, this is less of a concern.
As always, discuss your concerns with a board certified plastic surgeon (ABPS).

500cc is a large implant but it could be a good option depending on various factors such as your chest wall measurements, your tissue elasticity, your desired results and the skill and techniques of your surgeon. If you are still having second thoughts about the surgery, it would be best to have a detailed discussion with your surgeon regarding the processes involved in the surgery and the rationale for choosing 500cc.

If you desire to look top heavy  and have people  stare at your chest, then 500cc implants will do it. But a PE is necessary before making that determination. I would suggest some computer imaging and evaluation by an experienced PS.

My best advice: more communication.
It is definitely worth spending more time (prior to the date of surgery) with your plastic surgeon to discuss further.  As you know, it will be important for many reasons, that you feel comfortable that you and your plastic surgeon are on the "same page" prior to proceeding.
One question that might be helpful for you to consider: would you be more disappointed if you are slightly too big or slightly too small after the breast augmentation procedure?
Ultimately, careful communication of your goals (in my practice I prefer the use of goal pictures, direct examination/communication in front of a full-length mirror, in bra sizers, and computer imaging) as well as careful measurements (dimensional planning) will be critical.
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. For example, I have found that the use of words such as “natural” or "D or DD 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, the use of computer imaging has been very helpful during the communication process, in our practice.
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, after the use of temporary intraoperative sizers.
I hope this helps. Best wishes for an outcome that you will be very pleased with. 

Hello. Thank you for your inquiry.

It is important to have an in-person assessment regarding your concerns as it is difficult to determine virtually.
There are many different factors that go into choosing a breast implant size which will correspond with your body dimensions while concurrently achieving your aesthetic results. Some of these factors are: Implant size (CC's), Implant profile (Low, Moderate, High), Placement of the implant (Subglandular vs. Dual Plane) etc. We utilize smooth round cohesive silicone gel 'gummy bear' implants for the best results.
During a consultation your aesthetic goals are heard and taken into account with the measurements of your breasts and the integrity of your tissue, as well as level of ptosis (sag). From here we collectively can find your 'perfect fit'. You are able to try out sizers and different implants in our office such that you can get an idea of what size you would be post-operation. We also offer Crisalix 3D plastic surgery virtual simulator during our in-person and virtual consultations to preview potential results. After your consultation, you will receive your very own implant sizers to take home with you (at a small cost) whether or not you decide to go forward with your procedure.
I usually recommend that my patients stop smoking, take vitamin C daily, and avoid aspirin/ibuprofen and vitamin E 3 weeks prior to surgery. I specialize in the 24-hour Recovery method which minimizes trauma to the breast and decreases pain post-operatively.
We encourage you to look at our website and Instagram (drkaraplasticsurgery) for lots of before and after pictures!
Please note that this response does not substitute patient-doctor relationship. We welcome any and all patients seeking advice to come in for a complimentary consultation available for limited time only.
During the COVID-19, we are offering complimentary online consultations as well as in-office consultation with social distancing and masks. Procedure done in-hospital private surgical facility while taking covid-19 precautions. We utilize UV-light to clean the air of viruses and bacteria during our consultations and surgery.
We invite you to come in to discuss your options more thoroughly. Please send us an email at info@drkaraplasticsurgery.com with the subject line: "Attention Meagan" and we will be happy to coordinate your appointment!

M.Kara,MD,FRCSC (27+ years experience) - Specializing in 24 hour recovery/ out to dinner breast augmentation in-hospital private surgical facility for your added safety and peace of mind

The answer will depend on your goal. At your height and weight I would think 500cc will look extremely large and artificial. That may be your goal.  In general with my patients of your body size it seems something in the mid 300's or so gives a large C to a D cup.