Breast Implant Sizes Explained | Size, Shape & Profile

By Dr Benjamin Norris FRACS, Specialist Plastic Surgeon, Form & Face (Bondi Junction & Bella Vista, Sydney)

If you are trying to make sense of breast implant sizes, you have probably found it more confusing than you expected. Implants are not sold in cup sizes; the same number can look completely different from one woman to the next, and there are shapes and profiles to weigh up on top of the volume. It is a lot to take in, and most of the confusion comes from starting with a number rather than starting with your own body.

This guide breaks down how implant size, shape and profile actually work, why cup size is a poor way to plan, and how sizing is done properly at a consultation. Dr Benjamin Norris is a Specialist Plastic Surgeon (FRACS) who performs breast augmentation at Form & Face in Bondi Junction (Eastern Suburbs) and Bella Vista (The Hills District). The aim here is to help you walk into your consultation understanding the language, not to lock you into a number. All surgery carries risks, and the right choice always comes back to your individual measurements and goals.

How are breast implants measured? (why it is cc, not cup size)

Breast implants are measured in cubic centimetres (cc), a measure of volume, not cup size. A 300cc implant holds 300 cubic centimetres of filler, whether that is silicone gel or saline. Cup sizes, by contrast, are not standardised: a C cup varies between bra brands and countries, so it is far too loose a measure to plan surgery around.

Working in cc gives your surgeon something fixed to plan with. It also explains a common surprise: two women can both ask to “go up a cup” and still need quite different implants. The volume itself does not change. What that volume looks like, once it is in place, comes down to the body carrying it.

Why does the same cc look different on every body?

The single most important thing to understand about implant sizes is this: the same cc looks different on every body. A 350cc implant on a petite woman with a narrow chest looks far larger than the same 350cc on a taller woman with a broad frame. The number does not change; the canvas does.

A few features of your own anatomy decide how any given volume will look:

Chest and base width: how wide your chest is sets how much of the implant’s width you can carry naturally. A narrow chest cannot comfortably fit a wide implant.
Tissue cover: how much natural breast tissue and fat you have over the implant affects how visible or hidden it is, and how soft it feels.
Skin elasticity: looser or tighter skin changes how the breast drapes over the implant and how much volume it can hold well.
Overall frame and height: your shoulders, ribcage and torso length all shape how proportionate a given size appears.

This is why choosing by a number alone, or by copying a friend’s implant size, so often disappoints. Volume only means something once it matches the body it will sit on.

The three linked decisions: size, shape and profile

Size, shape and profile are not three separate choices made one at a time. They are worked out together, starting from your chest measurements rather than from a photo or a target number. Change one and the others usually have to shift too.

In practice, your base width tends to come first, because your chest can only comfortably carry an implant up to a certain width. Once that width is set, the profile (how much the implant projects forwards) determines how much volume you can add within it. Shape then influences the overall look, whether that is fuller and rounder or more gently sloped.

Working in this order, from measurements outward, is what produces a result that suits your frame. Working backwards from a number you have seen online usually does not.

Implant shape: round vs teardrop (anatomical)

The two main implant shapes are round and teardrop (also called anatomical). Round implants carry volume evenly, giving more fullness in the upper part of the breast. Teardrop implants are shaped with more volume at the bottom and a gentler slope at the top, which some people feel looks closer to a natural breast profile.

Neither shape is better in the abstract; they suit different goals and body types. A few points worth knowing:

Round implants: give upper-pole fullness and cannot rotate out of position, because they look the same whichever way they turn. Modern round implants still settle into a soft, natural-looking shape when standing.
Teardrop (anatomical) implants: give a sloped profile that some patients prefer, but because the shape is not symmetrical, there is a small risk of rotation, which can distort the breast and may need correcting.

Which shape suits you depends on your existing breast tissue, your frame, and the look you are after. This is a conversation to have at consultation, where the options can be tried against your own anatomy.

Implant profile: what do low, moderate, high and extra high mean?

Profile describes how far an implant projects forwards from the chest for a given base width. For the same volume, a higher-profile implant is narrower and projects more, while a lower-profile implant is wider and projects less. Profile is how a surgeon fits the right volume onto a specific chest width.

As a general rule, a narrower chest often suits a higher profile (to add volume without an implant that is too wide), while a broader chest can carry a lower or moderate profile comfortably. The main profile options are:

Profile	General characteristics
Low	Wider base, least forward projection. Suits broader chests wanting a subtle result.
Moderate	A balanced middle ground between width and projection.
Moderate plus	Slightly more projection than moderate, a very common all-rounder.
High	Narrower base, more forward projection. Often suits narrower chests.
Extra high	Narrowest base, greatest projection, for a more prominent result on a narrow frame.

Manufacturers do not all use the same labels, so do not get too attached to the words. The principle is what counts. Profile is the lever that lets a surgeon fit a suitable volume to the chest width you actually have.

A rough cc-to-cup-size guide (with a big caveat)

Patients ask for a conversion, so here is the rough one. Somewhere around 150cc to 200cc of added volume usually reads as about one cup size. On that basis, 250cc to 300cc might move someone up one to two cups. It is a ballpark figure and nothing more. It is not a promise about your result.

The caveat deserves more of your attention than the numbers do. Cup sizing is not standardised anywhere, and as above, the same cc sits differently on different bodies. Give two women 300cc implants and they can land in different bra sizes, because their frames, tissue and starting volume were never the same. Use the conversion to orient yourself, then leave the actual sizing to measurements taken at your consultation.

Placement: over or under the muscle, and why it matters for size

Depth matters here as much as volume. An implant can go under the chest muscle, usually in what is called a dual-plane position, or it can sit over the muscle and under the breast tissue, described as sub-glandular. How much natural tissue you have to cover the implant feeds straight into that decision.

Tissue cover is the key link to sizing. If you have thin tissue and choose a larger implant placed over the muscle, the edges of the implant are more likely to be visible or to show rippling. Placing the implant partly under the muscle adds cover, which can give a smoother, more natural result, particularly with larger volumes. Dr Norris will recommend a placement based on your tissue, your chosen size and your goals.

How is sizing actually done at a consultation?

Nobody picks a size off a chart. It is a hands-on process and it starts with a tape measure. Your surgeon takes your chest and base-width measurements, checks the quality of your skin and tissue with a gentle pinch test, and asks what you are hoping to look like afterwards. A sensible range comes out of that conversation, not before it.

Several tools help you picture the result:

Trial sizers: soft implant sizers placed inside a bra so you can see and feel an approximate volume on your own frame.
3D imaging: simulation software such as Crisalix can generate a rough visual of different volumes on a model of your body, which many patients find helpful for setting expectations.
Measured planning: once your base width is known, most implants on the market are ruled out immediately. What survives that filter is your shortlist.

Sizers and 3D images are useful, but they are approximations. They exist to help you form realistic expectations. They cannot show you your own result ahead of time, and no outcome can be guaranteed.

Common sizing mistakes to avoid

A handful of avoidable mistakes come up again and again in consultations:

Choosing by a friend’s cc. The same volume that suited them may look very different on your frame.
“Going as big as possible.” Oversized implants for your frame can stretch tissue, increase rippling, and raise the chance of problems and revision surgery down the track.
Ignoring your lifestyle. If you run, lift or play sport, very large implants can be less comfortable and harder to support.
Fixating on one number. A specific cc from a photo online tells you little without the measurements of the person it sat on.

Why choose Dr Norris for breast implant surgery in Sydney

Dr Benjamin Norris is a Specialist Plastic Surgeon and a Fellow of the Royal Australasian College of Surgeons in the Division of Plastic and Reconstructive Surgery (FRACS), which is the specialist surgical qualification recognised in Australia for this field. He has trained for more than 20 years, in Sydney and overseas, to reach full qualification as a Plastic and Reconstructive Surgeon. He is registered with the Australian Health Practitioner Regulation Agency (AHPRA registration number MED0001160589).

It is worth knowing that the title “Specialist Plastic Surgeon” is protected and regulated by AHPRA and the Medical Board of Australia, and is not the same as “cosmetic surgeon”. Implant sizing is a measurement-driven process, so it is worth understanding what that qualification covers before you decide who to consult.

Dr Norris takes a tissue-based approach to sizing, using measurements, trial sizers and, where helpful, 3D imaging, so you can set realistic expectations before surgery. Every procedure is performed in a fully accredited Sydney hospital with an experienced specialist anaesthetist, and every implant is recorded in the Australian Breast Device Registry. He is a member of ASPS and ASAPS, and Form & Face provides ongoing follow-up care after your surgery. Consultations are detailed and unhurried, with a full discussion of implant options and the risks involved.

Dr Norris consults and operates from two Sydney locations: Bondi Junction (Eastern Suburbs, Waverley Council) and Bella Vista (The Hills District, Greater Western Sydney). If you would like help working out the right size, shape and profile for your frame, the clearest next step is a consultation. You can book by calling 1800 376 677 or through the Form & Face contact page.

Independent profiles you can check for yourself:

Common questions about breast implant sizes

What size breast implant should I get?

There is no single right size, and no number can honestly be settled before you have been measured. What suits you follows from your chest and base-width measurements, how much tissue cover you have, the condition of your skin, and the look you are after. That is the reason sizing happens at a consultation, with a tape measure and trial sizers, rather than off a figure you have read somewhere.

How many cc is a good breast implant size?

Any cc can be right or wrong depending on your body. Common augmentations often fall somewhere between roughly 250cc and 400cc, but a good size for you is whatever suits your frame and goals. A petite frame and a broad frame can need very different volumes for a similar visual result.

What is the most popular breast implant size in Australia?

Volumes in the mid-range, broadly around 300cc to 400cc, are commonly requested, but popularity is not a reason to choose a size. What matters is how a volume sits on your individual chest width and tissue. A popular number on someone else can look completely different on you.

What is the difference between round and teardrop implants?

Round implants spread volume evenly, so they add fullness in the upper breast, and because they are symmetrical they cannot rotate out of position. Teardrop, or anatomical, implants hold more volume low down with a gentler slope at the top. They are not symmetrical, so rotation is a small but real risk with them. Which one suits you comes back to your anatomy and what you want.

What does implant profile mean?

Profile describes how far the implant sits forward from the chest at a given base width. Hold the volume steady and a higher profile will be narrower with more projection, while a lower profile spreads wider and projects less. It is the adjustment that lets a surgeon fit a suitable volume to your chest width.

How many cc equals one cup size?

As a very rough guide, roughly 150cc to 200cc of volume increases the breast by about one cup size. This is only an approximation, because cup sizes are not standardised and the same cc looks different on every body. Use it to get oriented, not as a promise.

Can I choose my implant size before my consultation?

You can research and bring a rough idea of the look you want, which is genuinely helpful. A firm size, though, can only be settled at consultation, once your chest is measured and sizers are tried on your frame. Coming in with goals rather than a fixed number tends to work best.

Medical references

Australian Society of Plastic Surgeons (ASPS). Breast augmentation procedure and implant information. Australia’s professional body for Specialist Plastic Surgeons, which publishes its own patient guidance.

Australian Breast Device Registry (ABDR). abdr.org.au. The national registry that records breast implants and monitors device safety in Australia.

Therapeutic Goods Administration (TGA). Breast Implant Hub. The TGA’s central consumer resource on breast implants, including safety updates.

Healthdirect Australia. Breast implants. Government-funded national health information service.

Cleveland Clinic. Breast Implants: Types, Surgery, Recovery and Risks. Medically reviewed patient information on implant types and considerations.

Medical disclaimer: This article is general information only and is not a substitute for personalised medical advice. Any surgical or invasive procedure carries risks, including bleeding, infection, scarring, changes in nipple or breast sensation, capsular contracture, rippling, implant malposition, asymmetry, and the possible need for further surgery. Individual results vary and outcomes cannot be guaranteed. A seven-day cooling-off period applies after you sign a consent form for a cosmetic surgical procedure. Before proceeding, always seek a second opinion from an appropriately qualified health practitioner. Read more about surgical risks at formandface.com.au/surgery-risks-and-complications/.

How to Choose Breast Implant Size, Shape and Profile: A Sydney Surgeon’s Guide