The Transfeminine Bra Fitting Guide

by Emma Cadence

(Cassi Speaking: I recently realized that this incredible resource no longer existed online. I’m reproducing it here to that it doesn’t get lost. I’ve made some effort to find Emma to ask permission without success. If this is your writing please feel empowered to ask me to take this down, and also thank you so much for this work. It was so valuable to me early on, and I’d hate for those who need it to not find it. It was originally hosted on http://emmacadence.com, I tried to preserve some of its formatting here. Thanks! <3)

There’s no way around it—shopping for bras sucks. Earlier this year, I learned that my modest rack had grown a bit since the last time I had shopped for bras and would need to find replacements. Unfortunately, due to the breakdown of society in the wake of COVID-19, that meant putting up nearly $1500 to buy 30 combinations of bra sizes and styles online only to return all but four of them. (To be fair, being in the throes of a major OCD flare-up made me a bit unreasonable.)


To be clear, bra shopping sucks for everyone. (If you ever want to bond with cis women for some reason, bitching about how much you hate bras is a pretty reliable way of seeming relatable.) But for those of us who are just learning to do this late in life, it’s much worse. Not only do we have to sift through the mountain of bra fitting discourse (yes, bra fitting discourse is very much a Thing), most of it isn’t even written for us in the first place.

But I have good news: you can find a bra that fits. Even better news: it might, in fact, be easier for “AMAB” folks with breasts to find well-fitting bras than it is for cis women. Read on.


I wrote this guide for trans women and other transfeminine people who are bra shopping for the first, second, or seventh time, in hopes that it would ease the frustration. (I suspect that this guide will be helpful to cis women, too, even if that isn’t my primary goal.) Specifically, this is for people who have taken hormones long enough to have breast growth. If you’ve had top surgery, much of the guide may still apply, but there may be some variances depending on the details of your surgery. Conversely, if you have started HRT only recently or haven’t started yet, much of this won’t really matter, but I’ll include a brief aside at the end.


I am not the first person to write a trans bra fitting guide, of course. The problem I have with other online style/trans/fashion advice is that most of them are pretty straightforward and didactic… which is a problem when they also happen to contradict each other, making it hard to know what to believe. And even if they all agreed, every body is different—especially trans bodies. A one-size-fits-all (har har har) solution cannot possibly spit out the one true formula for converting a few measurements to a well-fitting bra for everyone. And so, this is a guide for people who are frustrated by easy formulas and answers and want to understand what is actually going on when you are fitting yourself for a bra and how the garment sizing actually works. The goal is to learn how to think about bra fitting.


What are bras for?


Before we proceed, it’s important to understand the basics: why wear a bra in the first place? After all, people did fine without them for the bulk of human history. What does a bra even do?


First, a bra is supposed to provide physical support for the breasts. Contrary to the perennial canard that bras are torture devices, a well-fitting bra is in fact supposed to be more comfortable than wearing none at all. (Otherwise, I’d have posted something much shorter: burn your bras. Problem solved.) Breasts can be heavy, and supporting their weight can sometimes strain the back. (Hence FLBP—”Future Lower Back Problems”—the term coined by the douchebags fine gentlemen editors of men’s “entertainment” website, theCHIVE.) A good bra will more evenly distribute the load and also stabilize the breasts, relieving back pain. This is probably a more pressing concern for most cis women, but probably less so for trans women, as without top surgery our breasts aren’t particularly heavy. (Since this is most important concern with respect to sizing, it means that you have permission to chill out a bit. If, say, your cups fit but your band isn’t super tight, it’s not the end of the world, as long as you’re comfortable.)


Second, a bra provides some stability to prevent chafing between the nipple and clothing. This is probably the most important concern for trans women in early stage growth, when even the vibrations of walking down stairs are torture. The good news is you don’t need much, just a layer between the nipple and the shirt.


Third, a bra changes your silhouette under clothing, making your breast shape more even (or, in some cases, larger and rounder). And, crucially, in a culture that insists the female nipple is a sex object, it keeps your nipples from showing. This is probably the main reason that I personally wear a bra, despite not needing much physical support—it’s simply socially compulsory. Nevertheless, this does add some constraints to the fit—gaping cups, for example, will look weird under some clothes.


How Bra Sizing Works


Bra sizing is a paradox. On the one hand, because bra size really matters, bra sizing is remarkably precise, as it is for any other garment where size really matters (e.g., shoes). There is unanimous agreement about what “36C” means, for example, in terms of the size of the physical garment, and brands and styles don’t differ by more than a step. (Unlike, say, dresses, where I can fit into anything from an XS to an XL depending on the brand.) On the other hand, bra sizing has a such a bad reputation because there is wide disagreement about what kind of bodies these precisely-sized garments are supposed to fit.


Let’s start by just considering the sizes. Bras come in two dimensions: a band size, and a cup size. The band size is most straightforward. In the US, the band size is just a number of inches. The bands of a 36B and 36H should be exactly the same. Band sizes are all even numbers.


Cup size, contrary to popular belief, doesn’t actually measure anything on its own: it is a relative measure of the breast size to the band size. “A” does not mean “small” and “DD” does not mean “large”; the actual dimensions of the cups in a 40A bra are in fact the same size as the cups in a 32DD. In general, given a bra size, a bra that is one band size (that is, two inches) smaller than another bra, but with the same size cups, will have a letter size that is one larger: e.g., the cup sizes of 32C and 34B bras are the same. This phenomenon is called “sister sizing.” Again, this bears repeating: cup size is not an absolute measure of the size of your bust, but a relative one. I personally wear a 32D in some brands; nobody would ever say my breasts are large. When we get to the next section, this fact will be significant.


You may hear about so-called “UK” sizes, as well as European sizes. The usage varies by brand, but conversion charts can be found online. Many bra fitting blogs advocate for the UK system over the US, but the reality is that the two systems differ only in their handling of cup sizes above DD (the UK goes to E when US goes to DDD). The stereotypical transfeminine person won’t have breasts large enough for this to be an issue, but if you happen to require a larger cup size, just know that you need to confirm what the sizing system for that brand actually means. (Cis women: spoiler alert, but most of you actually do require bra sizes in this range.)


Bra Fitting: Matching Sizes to Bodies


So let’s talk about figuring out what size of bra works for you. As I mentioned before, this is the contentious part. The reason there is so much disagreement about measuring bra size is the “sister size” phenomenon mentioned above, in addition to the near-universal misconception that cup size actually measures something. If you change the way you measure your band size, you end up dramatically changing the cup size as well. So, by one method I am a 32D; by another I could be barely be considered to be a 36A.


The traditional algorithm is something like this: take measuring tape and measure your underbust (the area under your breasts). (Mine is about 33.25 inches). Add three, then round it to the nearest even number. (In my case, 36). Then measure your bust size in inches, subtract the number you got for the band size, and for each inch, go up a cup size starting from A. (My bust is about 36″ as it is, so by this algorithm I guess I would be a 36AA, if such a size exists.) There are variations to this method. For example, some methods add 2 or 4 to the measured underbust size instead of 3. Victoria’s Secret measures diagonally, from the underbust area in the back, to over the chest, which lengthens the measurement, but then doesn’t add anything. Regardless, the distinguishing property of the traditional method is that the band size is larger than the underbust measurement.


Against that, over the past few decades there have been online communities and blogs advocating for a new method of sizing. I am most familiar with the /r/ABraThatFits subreddit, but there is a similar group on facebook and these communities once existed on forums and blogrings in an earlier web. There is an online calculator (it even has an AMAB setting!) for their method, but the basic is this: don’t add anything to your underbust measurement, except to round. Cup size is determined by standing, leaning, and lying-down measurements and averaged with some math that, while simple, isn’t really important for the purpose of this post (the full algorithm can be found here, as well as an MTF-specific version). This results in bra sizes with much smaller band sizes and much larger apparent cup sizes than traditional fittings. Very few cis women have apparent cup sizes smaller than D (for their new band size) by this method; many are Fs or larger.


So, why use a more complicated method? The argument goes something like this. The traditional method for measuring bras comes from a time where stretchy synthetic materials didn’t really exist yet. Adding extra inches to the underbust was necessary for the garment to even fit. (36″ was also the ideal feminine measurement at some point in history, and since most women are smaller than that the pressure to add inches to get that 36 number might be an early instance of so-called vanity sizing.) But in a world with spandex and elastic, the extra inches aren’t necessary, and are in fact harmful. For most cis women, who are wearing bras for physical support, a tight band is necessary for the bra support the weight of the breasts.


There’s also some cynical reasons for this: Even if the traditional method is inadequate, it vastly simplifies the array of sizes that need to be made commercially available; the vast majority of customers will fit in sizes 32-40 and cup sizes A-D. (It’s also easier to make two measurements in a store; you don’t need to do any leaning or lying measurements and you don’t need your salespeople to do weighted averages in their heads.) The problem is that this leads to people wearing bras that seem to fit but don’t actually provide the necessary support and end up being uncomfortable.


If you haven’t picked up on it, I tend to favor the “online bra-fitting warriors” method, for a number of reasons. First, the online bra-fitting community is surprisingly trans-inclusive and they did a lot of work adjusting their formulas to work with transfeminine folks (and have some binding advice for transmascs). The same… can’t really be said for the garment industry, who will just listlessly repeat the same formula as if our bodies were the same as a cis woman’s.


But there’s also just a very pragmatic reason for it to: the ABTF method gives me a size that actually exists; the traditional method does not. The strange irony of being a trans woman is that, given a better method for bra fitting, it is actually far easier to find a bra in commercially-available sizes than it is for cis women, since cis women using this method will tend to have sizes larger than DD, which are rare in stores, while trans women (who haven’t had top surgery) will tend to have sizes in the A-D range. I am, of course, privileged to have a somewhat average frame; some trans women may have underbust sizes of 42, even without adjustments. But, regardless, the ABTF method tends to, on the whole, make finding a bra actually possible, while the traditional one doesn’t.


Ultimately, though, the result of any bra fitting system just gives you a starting point. By the ABTF calculator, I’m a 34B; in reality I’m a 34C or 32D. There are specific criteria that determine bra fit, that will be obvious when you actually put the garment on, which we’ll get to in a moment. But again, if you’re looking for a starting point for your first online order, the ABTF calculator comes highly recommended.


Breast Shape


Unfortunately, there’s more to this story. Breasts come in all shapes and sizes, and therefore the two dimensions of band size and cup size won’t suffice to cover three dimensions of complexity. Transfeminine people tend to have shallow breasts, which ABTF community covers in detail here, in addition to blog posts from around the web. You may well have a different shape, in which case you will need to do some investigation, but here are the highlights for shallow breasts:

  • Demi-cup and balconette bras tend to work best, as the cups of these styles don’t come up so high. Shallow breasts don’t have a lot of volume up top and so it might be hard to fill any coverage at the top of the cup.

  • Push-up bras are particularly challenging—because shallow breasts already start high on the chest, they don’t really need to be lifted up. Padding is generally a better bet. (I personally have found a push-up bra that works, but it’s a pretty unusual one).

  • Plunge bras tend to be particularly bad; although some brands are notable exceptions.

Actually Buying a Bra


So!  We’ve got all the preliminaries. Go get some tailor’s measuring tape, go to the calculator mentioned above, and fill it out. (Perhaps telling you to go use a different calculator is a bit anticlimactic, but the point is that you now know why you should use that one instead of the things that other sites will tell you, which is the point of this post.)


The number you get is a starting point.  Every body is different, and trans bodies are especially different depending on stages of transition, age, etc. Expect to try on several shapes and sizes. At this moment, I get a measurement of 34 B. There are lots of factors that might change this. For example, my underbust measurement is closer to 33 inches, and I have a lot of “squish” when I do a tight underbust measurement, and so in some brands I am actually better served by a 32 band size. But remember, to get the same size cups when I take the band size down, I need to go “up” an apparent cup size, even though nothing has changed—so that comes out to a 32C.


There are a number of things you need to consider when evaluating the fit of a bra.

  • Whenever you put on a bra, whether for every day wearing or trying it on in the store, you must “stoop, scoop, and swoop”: that is, stoop over, use your right hand to reach into the left cup and scoop up all the tissue—including tissue around the sides—and swoop it all into the cup. Then stand up straight again, and do it with the opposite side. (See this video for an example.)

  • Is the bra comfortable? This is a garment you will be likely be wearing at least twelve hours a day, every single day. Contrary to popular belief, a well-fitting bra can be comfortable—it should more comfortable than no bra, in fact. If it isn’t, put it back on the rack.

  • Is the band too small? Does it dig into your sides? Is it visibly digging into your back somehow? Does it create flabby chunks under your armpits or in your back? (Note that what might appear as flabs of armpit fat is sometimes actually breast tissue, which may be a cup size issue instead of a band size issue.)

  • Is the band too loose? There is a fairly reliable test for the band size: you should be able to put two to four fingers between the band and your back, just where the clasps are, and set them at a 90-degree angle against your back. But you should not be able to move your hand away from your back without great effort; the elastic should keep it in place.

  • Always buy bras with bands that that fit on the loosest hook. Modern bras stretch over time, so you need the other hooks to compensate for it six and twelve months down the road.

  • Are the shoulder straps tight, or falling off? Straps can be easily adjusted, so make sure to adjust them to a realistic length as you’re trying them on. (After you purchase a bra, you should re-tighten the straps about once a month.)

  • How do the underwires fit? Do they dig in to your skin at any point? How about when you move around? (If you’re reading this guide, you probably have wide, shallow breasts, so you will need bras with longer underwires.)

  • Are the cups too small? Is there any “spillover” along the tops of your breasts? Are the cups digging in? If so, go up a cup size.

  • Do you notice any blobs of “armpit fat” hanging out of your sides? That is often breast tissue that could be scooped into your cups… but sometimes it’s also an indication that your band is too tight. Also note that tissue on the side of your front shoulder may also be the “tail of spence”, a part of breast tissue that does not normally need to be in the cup. See this diagram and this post.

  • Are the cups too large? Feel around the cup of the bra. Is there any dead space where your breasts aren’t filling out the cups? Do you have any “gaping” at the top where it doesn’t quite meet the skin?

    This is really important: the area where the two cups meet in the middle is called the “center gore.” The gore is supposed to “tack”, that is, it is supposed to rest cleanly against your chest. Almost all bra fitting issues I have tend to be related to the center gore. This tends to be harder for transfeminine people because our rib cages tend to be wider, leading to some stretching and the gore sort of “floating” off the chest a bit. Sometimes this addressed by going down a sister size (i.e., smaller band, with compensating cup size change).

  • Okay, so you have a bra that seems to fit. How does it look under clothing? Some bras, especially those with lace or other decoration, can look weird under clothing. Be sure to bring, say, a tight-fitting top with you to the store. (Note also: white bras tend to show under white clothing; if you need something for that, find a bra closer to your skin tone.)

You will usually have to try several sizes to get it right. If I were starting from scratch, with an evaluated size of 34 B/C, given my measurements, I would probably try everything from a 32B-D and a 34A-C. (If you rounded your band size down, you would probably need to try one band size up). Even if you are confident in your size, you will need to try on several sizes. I recently ordered no less than 30 bras when going through my last bra-fitting journey during COVID-19 social distancing, because I couldn’t do any tryings-on in the store—there really are no shortcuts. (Thank goodness for return policies! Most places that sell bras understand.) And that was with me already knowing generally the sizes and styles that work for me! Be prepared to take a long time.


Never buy a bra without trying it on. Even if it’s the same style and size as a bra you already know that fits, but a different color, you still need to try it on. (You may think I’m joking, but this has literally been a problem for me before, at Aerie. The same style had tan and off-white colors; it turned out the off-white was made of a mix of slightly different material, and the band was looser.)


Not all bras are going to fit. As you get more experience, you may be able to tell early on if the problem is the bra or the size (e.g., a bra that fits in every way but the band is a little too stretchy is probably just a size issue; a bra that seems too fit except for the center gore is in my experience probably not going to be fixed by resizing). There is nothing wrong with you or your body if the bra doesn’t fit; it’s just not meant for bodies with your specific needs.


Do not be afraid to say “no” to a bra you don’t like, and conversely, do not be afraid to spend money, if you can afford it. You will be wearing bras for most of your waking hours. You should never dread wearing a specific bra, or hate the way one looks. Spending $60 on a good bra will get you far more bang for your buck than spending $60 on three T-shirts.


That said, because transfeminine people typically don’t have a major physics problem and can fit in commercially-available sizes, having an expensive bra isn’t as necessary. In fact, in your first year of transition, you should probably intentionally buy cheap bras, because you don’t know how much you will be growing. No need to invest $60 in something that you’ll have to replace in six months—you can go to Aerie or Target.


Taking Care of Your Bras


After doing all the work to find a bra that fits, you will want to take care of it so you don’t have to repeat the experience. Don’t wear the same bra every day; alternate when possible. Otherwise, you’ll stretch them out.


Cleaning bras also requires special care; they are delicate garments and expensive, and the washing machine will kill it. Hand-washing is not actually as hard as you might think. I recommend using a product called Soak; all you need to do is submerge your bra in a bowl with a teaspoon/capful of Soak for about fifteen minutes, and then hang it up to dry when you’re done. Regular laundry detergent will also work, but you will need to rinse it after taking it out of the water. If you must machine-wash a bra, use a lingerie bag and run it on gentle cycle. Never tumble dry a bra; even low heat will distort the wires.


Even hand washing a bra will cause strain on it, and so make sure you get 3-4 wears out of each bra before washing it. I usually have four bras, and each week I alternate between two of them.


Bras should last about a year. As I’ve been saying, trans women put a little less strain on bras than cis women, and so you may be able to squeeze some more use out it—just make sure to periodically evaluate the fit the same way you would a new bra (especially the band size, because that stretches). You’ll need to move to a new hook after several months of stretching, and you’ll probably need to retighten straps about once a month.


Other Situations


If you’re pre-HRT, you probably don’t need a bra. If you would like to wear a bra and especially if you want to stuff it, you don’t need to overthink it. Measure your underbust, round to the nearest even number, and choose a cup size. You don’t need to do anything fancy to stuff a bra under clothes; a sock or two will do wonders. If you’re stuffing, there is no need for a push-up bra; in my own experience it just looked kind of weird.


If you’ve just started HRT, are budding, and want to hide that fact while you are in “boy mode”, a sports bra is all you really need. Sports bras aren’t particularly complicated—they typically come in S/M/L sizing—just be sure to find one without padding. It’ll look like you’re just wearing a tank, so long as you aren’t wearing skin-tight clothes over it. If you can afford it, merino wool is a good fabric for keeping cool, and you can get several wears out of it (even while working out!).


Concluding Remarks

This has probably been a lot of information, so to conclude:

  • Use this calculator for finding the bra size to start with.

  • Bra shopping requires patience. Most bras won’t fit most people, even if you have what is theoretically the right size, and buying a bra that doesn’t fit is an uncomfortable mistake. Try not to go shopping when hungry, tired, or in a hurry, and bring a friend. 

That said, bra shopping is not actually impossible, and in many ways our smaller cup sizes make it easier to find bras in your size. Most cis women using the ABTF method could never hope to find their size represented at a place like Aerie (since the cup sizes in store only go up to DD or so), but I’ve had success there. There’s also far less at stake, because our bras do not usually need to solve complicated physics problems.


Hopefully this is helpful. I’m one person, and you shouldn’t take what I say as gospel; however, I hope I’ve given you the tools to understand why people make the claims about bra measurement that they do and you can put it in a broader context to find what works best for you. At the end of the day, you are the best judge of what your body needs and what looks good on you.