Bra Fitting: Are half-cup sizes helpful?

Here is something I've noticed as a trend emerging in bra fitting among some companies that make bras and lingerie: getting very specific about fit, right down to half-cup sizes and figuring out new ways to tell customers exactly which bra will work best for them. But, how much of this is useful information? When does it begin to become too confusing and discouraging for those who already struggle to navigate bra sizing because they don't conform to any standard fitting method?

Example 1: Petite Bra Fitting at Little Women

Some of the intense focus on fit can, in fact, be helpful -- like if a company is providing a necessary alternative size for an under-served population. For example, creating an AAA cup size is an interesting choice that some petite bra specialists have made in order to help very small women get a better idea of how their bras are scaled down to smaller proportions. Little Women, a UK boutique brand specializing in small-cup bras, sells AAA cups for those who find that AA cups are too large in volume; in other words, too deep.

What the AAA cup size does, in effect, is separate those who have a half-inch difference between full bust and underbust measurements (AA cup) from those who have less than that (AAA). Here's how it works at Little Women if you're shopping online: you take a fitting quiz, in which you are asked what size bra you are currently wearing and how well it fits. Depending on how tight or loose the band is, and whether you are spilling out of the cups or have gaps in them, you are then told to size up or down in one or the other, or both.

I experimented with this using A and AA cup sizing. In the fit quiz, what happens if you tell them you're wearing an A cup but it gaps significantly is that you are advised to try an AAA cup. If you tell them your bra gaps slightly, you are directed to try an AA.

Little Women bra size chart (there isn't one).

What this company doesn't do is provide a bra sizing chart to help customers figure out their own fit by measurement. Instead, as the screenshot at left from their website demonstrates, it strongly pushes its specialized fitting service via video or in-person consultation.

There is a brief explanation here, in their introduction to AAA cup sizing, about why this is necessary for small cup sizes -- but nothing about how to tell whether or not you'll be able to wear a size AA or if you really need the AAA. In this article, they also note that you

"may also consider AA cup bras for small busts or A cup bras for small breasts. Explore our bras for small busts." 

And so, at that point, women looking at these sizes are back at the beginning: consider all of them, and if you still don't know, we'll look at you over a video call and tell you what to get.

Helpful, or not? You tell me. I think if I had tried a number of different AA cup bras and none of them fit, I'd probably be interested in the AAA option. But in my experience helping very small-breasted women find a good bra, the half-inch difference between these two sizes is not substantial enough to guarantee that the AAA cup will reliably be a better option. That's because bras differ in cup structure, coverage level, material, shape, amount of padding, underwire or wireless... you get the idea. There are too many variables to be certain of fit when you're talking about less than half an inch.

Example 2: Half-Cup Sizes at ThirdLove

ThirdLove bra sizing chart.

ThirdLove is a company that offers a "100% Fit Guarantee." This quote is from one of their sponsored ads. The language should tell you something about what kind of marketing strategy they're using: the hard sell. This is defined in an AI overview search response from Google as follows:

A hard sell is an aggressive, high-pressure sales technique focused on getting a buyer to make an immediate purchase. It relies heavily on urgency, scarcity, and assertive persuasion rather than relationship-building. [1, 2, 3]

The phrase is also commonly used to describe an idea, product, or policy that is simply very difficult to convince people to accept or agree with. [1, 2]

But before we rush to judgment, let's take a look at where ThirdLove's promise of the perfect fit is coming from. Its sales tactics don't necessarily mean it isn't providing something valuable.

In fact, this company does provide lots of information about bra fitting for its customers. My own website, when I had an AI tool analyze it, compared unfavorably to ThirdLove in how many common questions about bra fitting I answer; the likely common perception of my level of expertise on the subject (lacking); and my overall estimated reputation as a trusted and well-liked source of guidance online ("neutral," while ThirdLove rated as highly positive).

The fitting method they're using is half-cup sizing, but not for unusual or difficult-to-measure dimensions. This is, more or less, calling yourself "B/C-ish," as I often do when describing my ideal bra size. Many, if not most, people are going to fit into this category. It's not often you'll find someone who is a perfect 34D, or any other bra size, every single time.

So in fact, half-cup sizing for average women who can easily find themselves on a standardized bra fitting chart does make sense... sort of. It's something most of us can relate to. For me, when I heard that they were doing this, I thought: "that sounds great. I love the idea of having a B/C-ish bra that fits me just right, as if it were made for my body." Who wouldn't want such a thing?

Unfortunately, according to many reviews of ThirdLove bras, my B/C-ish fantasy may be just that: a dream that they can't make into reality. Unlike Little Women, there is a chart for the brand's sizing; it does exactly what you would expect, which is separate cup sizes into "possibly this one, or maybe that one" by grouping them into flexible ranges. So if you're at the higher end of the B-cup range, for example, they call this a B+; smack in the middle, a B; and at the lower end, a B-... also known as A+.

Guess what: all B cup bras actually have this range. ThirdLove's bra size chart is the same as most others, with some overlap between both band and cup sizes so that it's possible to find your measurements corresponding to more than one size. All they've done is provide new labels for what is already provided by most other brands as well, and apparently it hasn't done much for how well their bras actually fit. Critics of ThirdLove have found its sizing unreliable and overly reliant on the stretch of their materials, rather than on proper technical construction based on shape.

Do some people love their bras? Sure, and that's just fine. But their marketing tactics strike me as deceptive, and what they're actually creating doesn't seem to be backing up all the hype of their claims. Compared to Little Women, a company that is in fact serving a demonstrated need, ThirdLove has not clearly established itself as having much of an impact on the evolution of bra fitting.