1. Same system, different scales
This is the most important one to wrap your head around. While most lingerie brands use 'cup and band' sizing eg 14C, 12DD, they actually use different scales for each size. This means one brands 14C can measure very differently to another brands 14C. It's a simple impossibility that you will be one size across a range of brands.
2. International variances
Countries have different systems within the 'cup and band' sizing model. For example in the USA they have D, DD and a DDD - this means their DDD is in fact an E cup. We also commonly see some European countries excluding the FF and GG, while many others include this. One of our brands, Anita, do not include a DD cup which means any size above a D will be a cup size out. Seriously, there is no way you can keep up with all this if you're not in the game 🤷.
3. Some styles just don't fit true to size
It's honestly that simple. Sometimes within brands we see certain styles fitting large in the cup, small in the band etc etc - as bra fitters we just automatically make the size adjustment for these styles. But it's important to not get disheartened by this if you're out shopping solo (not recommended 😉).
4. Understanding sister sizing is essential
Sister sizing is a whole seperate article in it's own right, but at least knowing that it's 'a thing' will set you ahead of most ladies. Sister sizing is referring to the fact that a 10DD and a 12D actually have the same cup volume/size, but fit differently in the band. They are 'sister sizes'. Cup sizes eg A or G cup are not a set unit of measurement, the cup volume is determined by the band size in combination with the cup size. So, if you're out shopping and the 12D fits well in the cup but is too firm in the back then you need to go for the 14C - not the 14D. The 14C in that instance will fit the same in the cup as the 12D, but will be roomier in the back. If you go for the 14D it will be a better fit in the back, but will have added a whole cup size of unnecessary volume. Phew! Get it? 🤷
5. Styles that aren't made for you
There is no bra that will work for every woman. Our breasts are set differently. Some are set wide, some are set close, some sit high, some sway low, some are voluminous, some are not. So if you are trying your hand at a style that perhaps isn't actually designed for 'you' then you may need to adjust your size to make it work. I'm not advocating it, but I know it happens a lot 'out there' so it's worth being aware of.
How do we tackle this at She Science?
Thanks for reading along. I am the co-founder and director of She Science, a Specialty Sports and Everyday Bra store in Melbourne. I have completed Advanced Bra Fitting training both locally and internationally as well as tertiary education in biomechanics. I love to follow the latest research on breast biomechanics and Sports Bra design to ensure that She Science remains the most advanced Sports Bra shopping environment in the world. I view my bra fitting business as a vehicle to inspire and enable women of all shapes and sizes to participate actively in life. Find me online via @SheScience.