Breast implant size is measured as volume in cubic centimetres (cc), while profile describes how far an implant projects from the chest compared with how wide its base is. Both are chosen to suit your chest measurements and tissue, not a bra cup size.
Most people start thinking about breast augmentation with a picture in mind, and often a cup size too. That’s completely normal. The planning, though, works in a different language: millimetres, cubic centimetres and how much stretch your skin has. This article explains that language, so the numbers you hear at consultation make more sense.
Why cup size is not used for planning
Surgeons don’t plan breast augmentation around cup sizes because bra sizing isn’t standardised. A C cup in one brand can fit like a D in another, and cup size depends on the band size it’s paired with. It also says nothing about the width of your chest or the thickness of your breast tissue.
Instead, planning is based on measurements that stay the same no matter which shop you walk into. Your surgeon may still ask how you’d like your breasts to look and feel, and that conversation matters. It just gets translated into dimensions rather than a letter on a label.
What does implant size (cc) actually mean?
Implant size refers to volume. One cubic centimetre is the same as one millilitre, so a 300cc implant holds roughly the volume of 300 ml of liquid. Implants come in a wide range of volumes, usually in small steps, so there is a lot of room to fine tune.
Volume on its own won’t tell you much about the final look, though. You can take 300cc and spread it over a wide, flat base, or fit it into a narrower implant that sits further forward. On a petite frame that may look quite obvious. On a broader chest it might barely show. So there isn’t really a size that suits everyone, and the number a friend chose says very little about what would work for you.
What is implant profile and projection?
Implant profile is how far an implant projects forward for a given base width. Projection is the forward measurement itself, from the back of the implant to its front. Two implants with the same volume but different profiles will sit and look differently on the same person.
Manufacturers use slightly different names, but the general idea is similar:
- Low profile implants are wider and flatter, with less forward projection.
- Moderate profile implants sit in the middle and are commonly used.
- High profile implants have a narrower base and project further forward for the same volume.
Some ranges also include in-between or extra-high options. No profile is better than another. Each simply suits different chest shapes and goals.
Base width and tissue cover
Ideally, the base of the implant matches the natural width of your breast. If it’s too wide, it can sit out towards the armpit or too close to the breastbone. If it’s too narrow, the breast may not look properly filled.
Tissue cover is just as important. Your skin, fat and breast tissue form the layer that drapes over the implant. Where that layer is thin, implant edges or folds (rippling) may be easier to see or feel, particularly with larger volumes. Where the implant sits, over or under the chest muscle, also makes a difference.
How size and profile are matched to you
Size and profile are matched through measurements and an examination, combined with an honest talk about your goals. Your surgeon will typically assess:
- The width and height of each breast, and the distance from the nipple to the fold underneath.
- How much your skin stretches, and how thick your upper and lower breast tissue is.
- The shape of your chest wall, and any differences between your two sides.
- Your lifestyle, work and exercise habits.
- The overall look you’d like, from subtle to more noticeable.
From there, a suitable range of implant dimensions can be worked out. Some surgeons use trial sizers worn in a bra, or imaging tools, to help patients picture different options. These can be useful, but they are only a guide. Your final result also depends on how your tissues respond and heal.
It’s worth saying clearly: no surgeon can promise a particular cup size. A good plan gives you a range that suits your body, along with a realistic idea of what that range may look like.
Round vs teardrop (anatomical) implants
Round implants are widely used in Australia. They are the same shape all the way around, so the look doesn’t change if one rotates within the pocket. Teardrop (anatomical) implants are fuller at the bottom and taper towards the top. They have more selected uses and need to stay in a set position, because rotation can change the breast shape.
Implant surface is part of this discussion too. In 2019 the Therapeutic Goods Administration (TGA) took regulatory action on a number of textured breast implants because of their association with breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), a rare cancer of the immune system. Your surgeon can explain which implant types are currently available and the reasons behind any recommendation.
Lifestyle, sport and implant size
It helps to think about what a normal week looks like for you. If you run, lift weights, ride or play contact sport, you might lean towards a more moderate volume, because bigger implants bring extra weight and movement during high-impact exercise. Some people with very large implants also notice that weight on their chest and shoulders as the years go on.
That said, there is no fixed rule. Plenty of active people choose a range of sizes. The aim is to find a size you can live with comfortably, both now and in the years ahead.
Future changes: pregnancy, weight and ageing
Pregnancy, breastfeeding, weight change and ageing can all change how breasts with implants look over time. The implant itself doesn’t change size, but the tissue around it does. Skin may stretch, breast volume may rise or fall, and some droop can develop.
These changes are worth thinking about before surgery, particularly if you’re planning a family or expect your weight to shift. Some people later consider further surgery, such as a breast lift with enlargement or implant exchange. Implants are not lifetime devices, and our article on how long breast implants last explains what to expect over time.
Risks of choosing an implant that is too large for your tissue
An implant that is too large for your tissue may increase the risk of certain problems. These can include thinning or stretching of the skin and breast tissue, visible or palpable implant edges, rippling, the implant sitting too low or too far to the side, and a greater chance of needing revision surgery later. Larger implants also add ongoing weight that your tissues have to support.
All breast augmentation carries risks, whatever the size or profile. These include bleeding, infection, capsular contracture (tightening of the scar tissue around the implant), changes in nipple or breast sensation, implant rupture, asymmetry and scarring. Rare conditions such as BIA-ALCL, and the range of symptoms some people describe as breast implant illness, should also be discussed. Our article are breast implants safe covers these in more detail.
Not everyone wants or suits implants. For a more modest change using your own tissue, fat transfer for a subtle volume increase may be an option worth discussing.
In Australia, cosmetic surgery requires a referral, preferably from your usual GP, at least two pre-operative consultations, and a cooling-off period of at least seven days before you can book surgery or pay a deposit. This gives you time to think through size, profile and risks. You may also wish to seek a second opinion from an appropriately qualified health practitioner.
FAQ
How do I choose the right breast implant size?
You choose implant size with your surgeon by matching implant volume and dimensions to your chest measurements, breast width, tissue thickness and goals. It is not based on cup size. The outcome is a suitable size range for your body rather than a guaranteed result.
What is the difference between implant size and profile?
Size is the implant’s volume, measured in cubic centimetres (cc). Profile is how far the implant projects from the chest for its base width. Two implants of the same size can look different because of their profile.
What does a breast implant’s profile refer to?
Profile is the relationship between how far the implant comes forward and how wide its base is. A low profile implant is broad and fairly flat. Moderate profile sits in between. A high profile implant has a narrower base and sits further forward, even at the same volume.
Can I choose my exact cup size before surgery?
No. A surgeon cannot guarantee an exact cup size, because bra sizes vary between brands and don’t reflect chest measurements. Planning uses cubic centimetres and millimetres, and your final result also depends on your tissue and healing.
Do larger implants cause more problems?
Implants that are too large for your tissue may increase the risk of skin thinning, rippling, visible edges, implant malposition and revision surgery. They also add weight your tissues must support over time. Your surgeon can help you balance your goals with what your anatomy can support.
About Dr Anh Nguyen, Specialist Plastic Surgeon in Perth
Dr Anh Nguyen is a female Specialist Plastic Surgeon based in Perth. She holds an MBBS (Hons) and a Postgraduate Diploma in Surgical Anatomy (PGradDipSurgAnat), and is a Fellow of the Royal Australasian College of Surgeons in Plastic and Reconstructive Surgery, FRACS (Plast). She is registered with AHPRA as a Specialist Plastic Surgeon (registration number MED0001193810) and is a member of the Australian Society of Plastic Surgeons (ASPS) and the Australasian Society of Aesthetic Plastic Surgeons (ASAPS).
Dr Anh studied medicine at the University of Melbourne and later completed an aesthetic fellowship at The Melbourne Institute of Plastic Surgery. In 2023 she was inducted into the Western Australia Women’s Hall of Fame for her contribution to healthcare.
At consultation, Dr Anh examines and measures your chest and breast tissue, talks through implant size, profile and placement, and explains the risks and recovery involved. You’ll also go through the two-consultation process and cooling-off period required in Australia, so there is time to think things over before making a decision.
Dr Anh is listed with these professional bodies:
- Australasian Board Certified Plastic Surgeons (ANZBCPS): https://boardcertified.org.au/surgeon/anh-nguyen/
- Australian Society of Plastic Surgeons (ASPS): https://plasticsurgery.org.au/surgeon/dr-anh-nguyen/
- Australasian Society of Aesthetic Plastic Surgeons (ASAPS): https://aestheticplasticsurgeons.org.au/surgeon/anh-nguyen/
Follow Dr Anh on Facebook (https://www.facebook.com/DrAnhNguyen/) and Instagram (@dranhnguyen).
To arrange a consultation, call (08) 9322 2659 or email enquiries@dranh.com.au. The clinic is at 88 Belmont Ave, Rivervale WA 6103. Please bring your GP referral to your first appointment.
Further reading
- How long do breast implants last?
- Are breast implants safe?
- How long does it take to recover from breast augmentation surgery?
- Breast lift with enlargement
Medical references
- Therapeutic Goods Administration (TGA), Breast implant hub
- TGA, Breast implant associated cancer: consumer information
- healthdirect, Breast augmentation (breast implants)
- Australian Society of Plastic Surgeons, Breast augmentation (implants)
- Australian Breast Device Registry (ABDR)
- Medical Board of Australia, Guidelines for registered medical practitioners who perform cosmetic surgery and procedures
- US Food and Drug Administration (FDA), Types of breast implants
- FDA, Risks and complications of breast implants
- Cleveland Clinic, Breast augmentation
- American Society of Plastic Surgeons, Breast implants
Disclaimer: This article provides general information only and is not a substitute for personalised medical advice. Any surgical or invasive procedure carries risks, and individual results vary. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.
