All About Bra Fitting: Bust Position and Torso Shape

For part three of my informal exploration into the elements of bra fit, I want to look at bust position and torso shape. A lot of bra advice focuses on the breast itself, and while that is hugely important, the torso that provides the base for the breast can have a dramatic effect on fit and comfort, too.

Since bra manufacturers are attempting to sell their design bra to as many people as possible, they have to settle on one averaged sizing standard that hopefully (sort of) fits as many of their customers as possible as a basis for their bra designs. As anyone who sews knows, it’s hard to fit a wide range of bodies with a specific sizing standard without the fit being off somewhere for most people, which is why patterns rarely fit perfectly right out of the envelope. The proportions of certain body measurements like back torso width to front torso width, breast diameter, and breast spacing can vary widely between women, but for production purposes for any given bra brand, there are only a single, averaged set of measures being used, unless the brand specializes in a particular subset of body types (petite, curvy, tall, plus sizes).

What this means is that if you have body proportions that differ dramatically from that standard, you may have certain fit problems. A simple, very common fit issue happens when bust spacing is different than the assumed standard, which is one to two finger widths apart. If your breasts have less space than this or are touching in the center, underwires in a standard bra don’t rest against the sternum, but instead sit painfully on top of or jab into the breast tissue, and there may be some gaping at the outer side of the cup. (A possible solution to this is a plunge style bra or a bra with a very low, narrow gore.) If your breasts are more widely spaced than the assumed standard, this will usually mean that the cup gapes in the center front near the gore while wires jab or rest on top of the breast tissue on the outer edge of the breast. (Bras with a wider center gore can help with this, and shorter wired styles like demi bras can help with wire issues on the outside of the breast.) Some other common bust position issues arise if your breasts have a wide or narrow root (more on this in a hugely-relevant-to-this-stuff future in-depth look at breast shape), or if your back is particularly broad or narrow. Both of these may throw off the proportions of the bra wings to the cup placement, landing underwires in the wrong place relative to the breast.

But there are also other, less obvious factors of body anatomy that complicate bra fit. Overall ribcage shape, both vertically and horizontally speaking, can dramatically affect how a bra rests against the body and whether the breast tissue can then fully supported by the cups. Since the majority of a bra’s support is provided by the bra band and the cups, if these aren’t positioned in a way to effectively hold and distribute the weight of breast tissue, the bra is unlikely to offer much support or comfort. Most mass bra production uses a horizontally oval shaped, vertically gradually tapered to the waistline type of rib cage shape as their baseline for shaping the bra band and positioning bra cups within it. But, of course, not all rib cages are shaped this way.

Here’s a great illustration of rib shapes viewed from the side that comes from a site (Butterfly Collection Blog) that seems down at the moment. (I don’t agree with the shape terminology used here, because I’ve seen rib flare describe something else in other contexts, curved vs. rounded is confusing, etc, but the visual is great).

Torso and Bra Fit

Vertically speaking, rib cages can be very straight, and barely taper to the waist at all, especially in more rectangular torso shapes without a very defined waistline. Rib cages can also be rounded or what might be called barrel chested, which means the ribs don’t taper inward toward the waistline as much as the standard but are more curved outward. Rib cages can be very dramatically tapered inward toward the waistline, especially in dramatic hourglass type shapes with a very small waist. Each of these variations will change the ratio of band to cup, and can require different adjustments to the vertical shape of the band to help it fit more closely to the body as it must in order to give adequate support..

Horizontally speaking, rib cages can have a variety of shapes other than oval that can mean the way breast tissue fills cups is different than with the standard oval shape. Here is an illustration of rib cage shapes in cross section that might help explain. It happens to be male, but you can get an idea of how breast tissue stacked on these shapes would cause breasts to project differently:


The “standard” chest has an oval shaped front and relatively flat chest wall on which the typical bra can rest evenly against the body. On a more barrel shaped chest, the chest wall is more rounded, and when a standard bra is positioned on this shape, bra cups may point outward in what is often called an east/west position. I’m not an expert on anatomy and my knowledge here is limited, but I’d expect that bodies exist in a continuum of shapes, and that the projecting rib cage (pectus carinatum) and inwardly curved rib cage (pectus excavatum) pictured here are probably extreme examples of shapes that occur to a lesser degree in plenty of people.

From what I’ve been able to find about these variations, a convex, outwardly curving front rib cage shape causes a range of fit problems because of how a bra rests against this shape and where the breast tissue is distributed relative to the resulting angle of the bra cups. Bra cups may be too far apart, with gaping at the sides and not enough fullness in the center front of the cup. Fashion Incubator has a great in depth write up on this particular shape with some illustrative pictures here.

My intuition is that with a chest wall that curves in a more concave way in front, the fit problems in a standard bra might be similar but reversed. My guess is that a standard bra would be tilted inward in a way that it would smoosh the cups together. The problem then is that the cups will be positioned differently than the breast tissue is actually distributed on the body, so there may be some gapping in the center front of the cups, and they might not be full enough to contain all the breast tissue at the sides. I suspect underwires might be especially uncomfortable in the center for this body type.

This is a lot of information and it seems a bit overwhelming, but my belief is that better fit begins with a better understanding of one’s own body shape. Knowing the physical factors that affect bra fit can help you know where to begin to look for answers. The internet has some amazing resources that deal with issues like these in depth, like Her Room, which links to recommended bra brands known to work well for specific fit issues, or Bratabase, which is a community dedicated to finding good fit and reviewing bra brands by actual wearers. There’s even a reddit community dedicated to A Bra That Fits.

I also feel like there is a huge amount of psychological baggage that comes along with bra fitting. A bra that flatters us can make us feel not only comfortable but attractive and confident. Trying on 37 bras and not ever being able to feel good about the results has this nasty way of eating away at your confidence. Never being able to find a standard bra that fit well or looked good on me for at least a decade of adulthood (along with a ton of jokes about being small chested in the era of cleavage and push up bra fashion) gave me a lot of negative feels about my appearance. Sadly, I know my experience is very, very, very common, and that no matter what shape or size they are, it’s all too easy for women (and men) to feel that there is something inferior or inadequate about their bodies. I’d like to yell it from the rooftops now that just because a person’s body doesn’t fit the “standard” doesn’t mean it’s somehow lesser or there’s something “wrong.” All fit standards are abstractions, not ideals. And even the fit “problems” I describe above aren’t “problems” so much as merely shape differences that just require style tweaks or certain adjustments in order to achieve support and comfort.

I think that’s it for today (*climbs down from favored soapbox*), but my next deep dive in bra fitting will explore the very related issue of breast shape and underwire types. (For quick reference, here are part one, Anatomy of a Bra and How to Know if a Bra Fits and part two, All About the Bra Band: It’s Cantilevered!).



All About the Bra Band: It’s Cantilevered!

For part two of my exploration of the bra, an in depth look at the bra band, its relationship to cup size, and its role in complicating everything about finding a bra that fits. 

The bra band is really the base of the bra. It’s where the vast majority of the support comes from, and the support it provides is cantilevered horizontally from the close fitted band and the cups holding the weight of the bust up, rather than support by suspending weight from the shoulders, which hurts and doesn’t work very well. 

vertigo cantilevered bra
Oh, yes, Jimmy, it is a veritable marvel of modern engineering.

The bra band also establishes circumference of the torso at the underbust (for simplicity, I’m disregarding for a moment the way that the old plus four inches issue muddies the waters for certain sizing systems). Bra band size is the starting point for how we describe bra sizes. Cup sizes are relative, and the letters actually have no meaning without a bra band to give them context. Even though we talk about double Ds or B cups as if they describe an objective size, they actually don’t mean anything, because they are relative to the band size that defines them. Here’s a better visual explanation of how cup size relates to torso/band size:

The way that we write bra sizes as a numerical value and a letter is kind of like a little math equation where the bra band is the base circumference of the body at the underbust, and each letter increase adds an inch to this to end up with enough room for the circumference of the bust at the fullest point:

AA = .5 inch

A = 1 inch

B = 2 inch

C = 3 inch

D = 4 inch

DD or E = 5 inch

And upward, though the specific letters used sometimes vary from manufacturer to manufacturer or European system versus American sizing system, etc. If you wrote it as a math problem, it would be something like this: 

Numerical band size/underbust circumference + letter to specify extra cup inches = full bust circumference

So for a 36B, it’s basically an equation that says: 36″ rib cage + 2″ total added in the cups = 38″ full bust measurement. This is why sister sizing works, where you can go down a band size but a cup letter, or up a band size and down a cup letter, to approximate a fit like your exact size (more on this another day).  

This sounds simple enough, but then everything gets complicated, because A) different fabrics are reduced by different amounts depending on stretch and recovery properties, so a band designed for a 36″ rib cage probably will measure smaller than that, B) all bodies are not the same and the broad backed and non-standard torso-ed among us (*raises both hands*) are statistical outliers who can’t find an appropriate size this way, and C) the plus 4 phenomenon.

The plus four thing is an often repeated piece of advice bra fitting – take your actual rib cage measurement, if it’s even, add four inches, and if it’s odd, add five inches to get your band size. To me, this seems illogical and stupidly complicated, and it seems more intuitive to just use your actual rib cage measurement. There are interesting historical reasons that this developed that I’m reading up on and will write about, but it seems to have been a vanity sizing tick that happened around the ‘50s or ‘60s when bra sizing as we now know it began to emerge as an industry standard. Things get really, really complicated these days, because sizing standards vary by market (American, UK, EU, Japanese, Australian, to name a few), and because in the US market, some companies no longer add these inches into the band sizes, and some companies do. This means a 36 band brand A might not be drafted for the same rib circumference as brand B, so your 36B is not the same size across brands. For those of us who don’t want to try on 37 bras at the mall to find one with a good fit, this is exasperating.

This isn’t exactly the bra manufacturer’s fault, since it is very hard to accommodate the wide range of bust shapes, sizes, and body proportions that exist in the real world into a single approximation. It’s a complicated supply/demand and consumer knowledge problem. Even if there were more variations available, most of us (my pre-lingerie-addiction self included) would not know where to begin to understand our particular shape and support needs. That being said, some kind of standardization on band measurement seems to me like it would make it much easier for all of us. (In my own drafting and bra sizing, I use an exact rib cage measurement as a starting point, since the plus four model assumes a certain standard tapered rib cage typical of more of an hourglass shape than the vast majority of women have. Statistically most of us are much more rectangular.)

I’ll be rambling about bust position next in my sprawling Ted talk on the mechanics of the bra. 🙂 I’d love to hear any thoughts, and if anyone knows more about the weird history of bra size standards, I’d love to hear more on this.

Achievement Unlocked: New Etsy Shop

I’m excited (and a bit jittery) to say that my Etsy lingerie shop is finally open. I’ve been setting it up for a few weeks and still have *so many things* I want to add to it, but it’s a start that I feel proud of. Also excited to say I’m testing sizing and writing up directions for a sewing pattern I hope to release soon. The crafter life goals of sewing for others and pattern drafting do work well together.

So far, no full cradle bras because I’m writing up my 95 theses of how to fit a bra. Not really 95, but a few pages for sure. I’ve been reading a lot on sizing standards and the history of different measurement practices and vanity sizing, and now I see why most of us are totally confused by manufacturer sizing. More on this later when I get my fitting guide all hammered out, but the issue of adding four or five inches to your underbust measurement really throws a wrench in everything. What’s even more frustrating is that just using your raw underbust measure seems like it would clear up everything, but then you have to grapple with figuring out which manufacturers add inches to the underbust measure for their bands and which don’t, and with how individual brands approach sizing, because a 36B in one brand might be another brand’s 32DD. (I intend to use the raw underbust measure, myself, though I’ve found the high bust to be a better place to measure – right under the armpits, over the bonier part of the upper chest, since the underbust measure can vary so dramatically with breathing, sitting vs. standing, bloating, etc. It tends to be slightly larger than the underbust measure by an inch or two, which works out perfectly for me with my broad back and unusual proportions, but may not for everyone.)

For now, I’ve focused on lacy bralettes, underwear and garter belts in the shop, and I’m still learning the ins and outs of SEO and writing copy and it’s been actually kind of amazing in researching all of that to realize how much snake oil marketing stuff floating around out there is promising starry-eyed budding entrepreneurial dreamer types like myself that a fortune is there for the taking if we just fork out 2k for whatever guru’s online course! Ugh, gross. (They tell me that if I don’t set up a mailing list, the howling abyss demon of failure and loneliness and bad skin will come for me, so if you’d like to join the mailing list, it’s (here), and I did set up a 10% off code that will be sent to your email, and I promise I won’t spam you. Especially not with false scarcity marketing or canned enthusiasm adspeak crap, because the world has more than enough of that.)

Learning photography is infinitely more fun, though I think I lost at least a week to cussing my camera controls and my cat for jumping in the shot when I finally got all the elastics to lie flat for two seconds. You can really see the eternal conflict between my antique feminine, Marie Antoinette delicate aesthetic and my Morticia Addams for life/what would Cersei wear sensibilities:

And now I’m off to bed to listen to the rain. Mmm, gothic novel spring weather.