Are You Wearing the Wrong Size Bra?

Like many items of apparel, how you feel about bras has likely been influenced by when you grew up. But, your choice of silhouette isn’t just a fashion statement. A woman’s choice of what does—or doesn’t—support her décolletage has come to imply more about her social views than practical needs.

The evolution didn’t jump straight from bullet to wonder, either. Check out this brief glimpse showing the modern bra’s many iterations:

If you gave it a watch, you might have noticed that many versions focus more on forcing a woman’s figure to conform to whatever silhouette is currently fashionable, more so than providing actual fit and support.

It’s this attitude of form over function that’s led to so many women (an estimated 80 percent) flat-out wearing the wrong bra size. That number almost makes you wonder, is there any reason to wear one at all?

To Bra or Not to Bra

This is as good spot as any to acknowledge that there’s no proof that wearing any bra, well-fitting or otherwise, staves off the eventual sagging of your breasts. There’s actually evidence to the contrary.

A 15-year study conducted by French professor Jean-Denis Rouillon tracked over 330 volunteers between the ages of 18-35. The final data showed that bra-wearers suffered increased boob-droop when compared to their unrestrained counterparts:

“Women who did not wear bras had a 7 millimeter lift as measured from their nipples each year. Their breasts were also firmer, and their stretch marks faded. There was also no evidence that the bras helped get rid of back pain.”

According to Rouillon, his results confirm that breasts don’t benefit from being deprived of gravity. Instead, he believes that wearing bras prevents the growth of breast tissue and leads to deterioration of the muscles that support breasts during regular movement.

Does the above mean you should burn your lingerie drawer? It’s entirely up to you. Rouillion’s research got a lot of press. However, it was considered only preliminary and, to date, there has yet to be any additional research supporting his findings.

How to Determine Your Bra Size

Sure, determining your correct fit is a tedious task at first, but wearing an ill-fitting bra isn’t any better. Not only can sporting the incorrect size cause your clothing to fit poorly, it feels uncomfortable—sometimes suffocating—and can lead to back and neck pain.

Take Your Measurements

Determining your bra size takes no less than five measurements, so grab your soft measuring tape. Also, note that these should be taken without a shirt or a bra:

  1. Your underbust comfortably snug (neither inhale or exhale for this, take it in a neutral position)
  2. Your underbust as tight as possible (exhale as much as possible for this, and pull the tape as tight as you can)
  3. Your bust while standing
  4. Your bust while leaning over 90 degrees
  5. Your bust while lying down

Calculate Your Size

Enter your five measurements into this bra size calculator. Most bra size calculators, including the one we’ve linked to, result in your UK bra size. That’s because UK sizes are standardized, unlike US bra sizes, leading many well-known brands on both sides of the pond to use this system. 

This means it’s most helpful to start off learning your UK bra size, then convert to your US size from there. The bra size calculator above shows a table converting both band and cup measurements.

Conversion tables still don’t help consumers overcome the lack of standardization found in US bra sizes. Some retailers, such as Her Room, attempt to help shoppers navigate various brand’s sizing systems by creating a universal cup size—you can check out their system here.

How to Tell Your Cup Size: Misconceptions About Cup Size

Many women believe that the average bust is between an A and C cup, while D+ measurements are reserved for the very well endowed—leading to shock at the letter cup size calculated from their measurements.

How could you really be an H after years of sporting size C cups? It starts with what’s providing support.

Instead of depending on shoulder straps, 80 percent of support should come from a bra’s band. To get the right fit, your band size should be the same as the underbust measurement; sizing methods that advocate adding inches or using the overbust method to determine band size are outdated.

Further, cup size isn’t static. Because bra cup size is relative to band size, when a bra’s band size increases, the relative cup volume is decreased. Conversely, when a bra's band size decreases, the relative cup volume increases. For example, a 28E is much smaller in volume than a 38E.

So, if you’ve been incorrectly wearing a band size 38, and now find that you should be supported by a band size of 32, your cup size will jump up by four letters.

To help women gain a realistic understanding of what their size looks like, the Bra Band Project features user-submitted images of different body types categorized by band and cup measurements.

Understanding How the Shape of Your Breasts Affects the Size of the Bra

Just like those with wider feet might need to go up a shoe size when sporting a heeled shoe, the shape of your breasts also plays a role in how certain styles of bra fit. 

One common shape difference is projected versus shallow shapes: Shallow breasts have the tissue spread out over a wider or taller root (where your breast meets your chest). This shape often struggles with bras cutting into your breast tissue at the top of the cup. Alternately, projected breasts have tissue that sticks out more and generally has a narrower or shorter root.

Identifying labels for top & bottom shapesClick the image to enlarge. Image via Reddit

Other factors that influence fit are bottom fullness or breasts that are splayed (pointing outwards). Again, Her Room has devised a helpful “Classify Your Breasts” quiz that guides users through various shape questions before suggesting different brands and models based on fit. You can find the tool here, but be warned that it features illustrations of bare breasts and is not safe for work.

How to Tell If Your Bra Fits Correctly

Checking if a bra fits well means looking at each part, including the band, straps, cups, wires, and the gore (which is the piece in between the cups, over your sternum):

Band: A properly fitting bra band shouldn’t ride up in the front or back, nor should it feel uncomfortably tight. If you think you’ve calculated your band size correctly, but it still feels uncomfortably tight, your cup size may be too small. To test the fit of the bra band alone, put on your bra backward (or upside down), so that your breasts aren’t putting strain on the cups. It should be snug enough that you can’t pull the band more than two finger widths away from your body. If your band now fits correctly when on backward, go up a cup size but stay the same band size.

Straps: Straps shouldn’t be painful, but they also shouldn’t be so loose that they slip off your shoulders. If your straps continue to dig into your shoulders, your band may be too loose for proper support. While a good fit can usually be found by adjusting straps to comfort, women with narrow or sloping shoulders may need to purchase racerback clips to solve the problem of slipping. 

Cups: Your breasts should fill cups completely without overflowing. One sign of poorly fitting cups are wrinkles, which indicate that cups are either an incorrect shape or too large of a size. However, if you’re spilling out the sides of your bra cups or experiencing “quad-boob” (when the top of your bra causes an indent in breast tissue like a muffin top), you’ll likely need to size up.

Wires: These should follow where your breast meets your chest wall without sitting on breast tissue—another sign that cups may be too small.

Gore: This triangle-shaped piece of fabric should lay flat against your sternum. If it floats, meaning that there’s a space in between the gore and your skin, it’s likely that your cup size is too small. An exception is women who have a sunken sternum, otherwise known as pectus excavatum, who will experience a floating gore even with a perfect fit.

Here’s a handy chart of how to tackle fit each fit problem:

Bra Fit IssuesClick the image to enlarge.

Because you might be experiencing more than one fit issue, you may need to combine multiple remedies to achieve your perfect fit. For example, if a 36B’s band rides up while simultaneously being too-tight in the cups, they would need to go down a band size and up one cup volume, resulting in a 36B on the chart below:

Bra sizingClick the image to enlarge.

If you’re left a little confused by bra size charts, you can find an even more in-depth explanation of how to read them here or check out the video below:

Making Sure Your Favorite Bras Last

Now that you’ve gone to all the trouble of finding a bra that fits correctly, you’ll want to make sure that the garment lasts as long as possible. How to best care for your bras?

  1. Don’t wear the same bra every day. It’s important to rotate the bras you wear, making sure they get at least a day or two of rest. The time off allows a bra’s elastic to regain its shape.

  2. Hand wash your bras. Because they’re in direct contact with your skin, bras should be washed after every two to three wears—which is fairly frequent. To help keep them in tip-top shape, consider purchasing a lingerie wash or using gentle baby shampoo. If you must machine wash, use a lingerie bag and choose the most delicate cycle your machine offers.

  3. Air dry only. Using any kind of heat to dry your bras can damage the elastic, cause your band to wear out, and shift around molded materials—all of which lead to a poor fit.

Even with exceptional care, bras generally need to be replaced after six months to one year of wear. Signs that a bra needs to be replaced include:

  • A band that’s become loose and no longer offers support
  • Underwires that are poking through
  • Cups that have lost their shape
  • A band that curls when lying down, indicating that the elastic has lost its shape
  • Fabric that’s started to fray

How long a bra lasts depends on how often you wear it and how well-constructed it was to begin with. Bras fall under the “you get what you pay for” category, as some versions contain up to 50 individual pieces! If you’re wondering why they cost so much in the first place, you can learn more about bra construction here.

A Well-Fitting Bra Should Be Comfortable

No matter what kind of bra you choose, finding a comfortable piece generally means you've also found one that fits. Trying on your bra before purchasing—even if it's the size you usually wear—is highly recommended.

We also recommend that you try on bras underneath a few of your go-to wardrobe pieces, especially since it’s helpful to see how your bra looks in your favorite tee, sweater, or blouse.

Additionally, seeing the shape a bra creates with your favorite clothes on can often help you assess its fit a bit more objectively, since we’re all prone to concentrate on (sometimes skewed) body perceptions in the buff.

Bottom line? Selecting your bra definitely causes some added frustration, especially since so many women are wearing the wrong bra size to begin with. 

Just remember that whether you’re trying on what’s currently in your closet or shopping for new bras in the store, a finding the right fit is all about how it feels—no matter what size is on the label.

Autumn Yates

Autumn draws from a reporting background and years of experience working remotely, while living abroad, to focus on topics in travel, beauty, and online safety.

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