An In Depth Look at Bra Fitting


  • Bras are designed using an averaged set of body measurements intended to fall somewhere in the middle of the wide range of body shapes and sizes, with the hope that it will provide an acceptable fit for as many people as possible. Since bodies have so many different proportions, bone structures, and tissue distributions, the average measurements that most bras are designed for can’t accommodate bodies that vary from that abstracted standard very well.
  • Sizing standards are confusing and inconsistent. Size labeling conventions vary widely from brand to brand, and some brands skew their standards using vanity sizing. Internationally, different markets rely on different sizing naming systems and even different systems of measurement (imperial vs. metric). All of this makes it very difficult to determine which size works best across all manufacturers and markets. 
  • Most of us don’t know our own body measurements or how our breast shape compares to the abstract standard most bras are designed to fit, and so don’t know where to begin to find bras that work best for our fit and support needs.


The simplest way to measure yourself for a bra is to take your full bust measurement and your underbust measurement. In US markets, your band size is typically the underbust measurement (plus four inches if even, plus five inches if odd). Your cup size is the difference between your full bust measurement and your underbust measurement, where each inch represents an increase in cup size.


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The more accurate way, especially if your rib cage or back proportions are broad or narrow, is to measure the front and back halves of the body separately. Measure your body circumference to get your band size, but to determine cup size, measure the full bust measurement in the front of the body only and the underbust measurement in the front of the body only. (It can be helpful to mark reference lines at your sides with something like an eyeliner pencil to be precise.)

Measuring yourself in this way can also be helpful as a starting point for analyzing your breast shape, spacing, and width as well, especially using an eyeliner pencil to mark your precise breast root where it meets the chest wall. If it isn’t clear exactly where this is, it can be helpful to push the breast tissue upward, downward, and side to side to see where the breast tissue meets the chest. It’s helpful to note if your breast spacing in the center is wider or closer than the approximate two fingers width that most bras use as a spacing standard. To consider breast shape, analyze the way the tissue is distributed, the amount of projection you have, and where the fullness is.


When shopping for ready to wear, using your measurements can help you know where to start in trying on different brands and sizes. There is so much difference in sizing and naming conventions between manufacturers, however, that fit testing is best because you may wear different sizes in different brands and styles.

Consider the band first, and independently of the other parts of the bra, since the bra band is so crucial for support, and because cup size is determined relative to band size. I’d suggest trying on bras without putting the cups in place or the straps on the shoulders to begin with. (For more about the function and importance of the bra band, see here.) When trying on, look for a band that fits closely to the body on the first hook of the closure, with wires that comfortably fit the shape of the breast root without digging, pinching, or sitting on top of the actual tissue. (For more on bust position and torso shape, see here.)

Once you’re satisfied with the band size, then start to look at cups. It’s easy to get the wrong cup size in part because it’s easy to mistake too shallow cups that hold breast tissue in place by compression for a proper fit. Ideally, though, the bridge in the center front of the bra should be flat against the sternum and the cups should encase the tissue. If the bridge is pulled away from the sternum, there isn’t enough depth in the cups.

It can also be difficult to find a cup that fits because most are drafted for a round shape with a lot of fullness on top. If you have less projection than that standard or less fullness on the top of the cup, there may be gaping and wrinkling that makes it seem like the is too large, but going down a cup size is too small in the wire area. The reverse is true as well, where if your breast shape has more fullness on top than the assumed standard, it can dig into tissue and seem too small, though increasing the cup size means a larger wire that may not fit the breast root correctly. This is where it can be helpful to know your shape and what styles work best for different tissue distributions.

For some of us, finding a properly fitting bra in ready to wear is still a more time consuming, often expensive trial and error process. If you have persistent problems finding a comfortable, supportive bra that fits your aesthetic and makes you feel good in it, sewing your own or having bras custom made can be a great alternative.