It’s time to figure out your real bra size

Heavy is the head that wears the crown—and so is the back that carries around big boobs.
Bras should be cute, but above all, functional. Klaus Nielsen / Pexels

As vital and fun as breasts are, they can also be a real pain. Wearing the right bra size can solve a lot of the problems that come with an ample bosom, but utterly confusing sizing systems and an overall lack of education about the functional role of these garments prevent large swaths of people from getting the chest support they need. 

Picking the right bra size for you is easier said than done, but knowing what to look for can help you avoid garments that look nice but do little, and go for the ones that will take a load off your shoulders—literally. 

It’s not about fashion—it’s about health

Bras are definitely an iconic fashion item: they can be haute couture, made out of precious jewels, come in myriad colors, and even have your favorite cartoon characters all over them.  

What we often forget is that bras were conceived as functional garments first. Stylish bras are nice, but they’re no good if they’re not doing what they’re supposed to do. A 2014 study found 50 percent of its participants reported suffering from breast pain, while research published in 2018 identified neck, shoulder, and back pain as other effects stemming from a lack of support. These issues can eventually result in bad posture, permanently grooved skin under the bra straps, spinal problems, unnecessary breast reduction surgeries, and even neurological issues. And it makes sense: breasts can weigh up to 2 pounds each

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“You have nerves in your arms where the bra strap sits, and if there’s really high pressure, sometimes it can cause numbness, and pins and needles, down the arm and into the hand,” says Joanna Wakefield-Scurr, professor of biomechanics and head of the Research Group in Breast Health at the University of Portsmouth in the UK. “We’ve even seen cases of complete paralysis in the little finger because of the pressure of the shoulder strap.” 

Breast structure also makes them prone to stretch marks. The glandular tissue—one of the three types of breast tissue—is only attached to the body by delicate skin and ligaments. Lack of proper support forces the skin to stretch and rupture with gravity, leaving permanent scarring, Wakefield-Scurr says.   

Then there are the psychological consequences of wearing an ill-fitting bra, which can have their own health repercussions. 

“Women with large breasts tend not to exercise as much,” says Jenette Goldstein, founder of Jenette Bras, a specialized bra store with locations in Los Angeles and Atlanta. “It starts when they’re young girls—can’t find a good sports bra, they’re bouncing around, they’re embarrassed, so they don’t exercise. It’s harder to run with large breasts.” 

This is not only based on anecdotal evidence. A 2018 study, for example, found that larger breasts are associated with less frequent and less intense exercise. The 355 Australian women who participated in that research said their breast size was one of the reasons why they were not exercising as much or as intensely as other women.

How to find a bra that fits

Ideally, everyone who needs a bra would go to their local bra store and get fitted by a professional once a year, Goldstein says. Unfortunately, this is not an option for many people, and because there’s no standard level of competency for bra fitters at stores, the trip may end with the purchase of yet another ill-fitting bra. This is why it’s important to know what to look for so you know if it’s a match or if you should continue swiping left. 

Try on every bra

There’s no way around it: the best way to know for sure if a bra fits is to try it on. This can be a problem if you’ve reduced your shopping to scrolling through websites, but if your goal is to find a well-fitting bra, doing your business IRL is your best bet. 

Keep in mind that once you find the bra equivalent to your personal Holy Grail, you may not be able to get the same fit, even within the same brand. Manufacturers sometimes change materials and patterns, so a specific size and model that fits great one day might feel a little big a year later. And the more elastic a fabric is, the less support it provides, Goldstein says. Even dyeing processes can affect sizing, with darker colors making for denser, more supportive fabrics, Wakefield-Scurr explains. You’ll need to keep trying bras on before you buy them.

Get the band right

You might think the straps provide most of the support, but the unsung hero of the bra is actually the band (or under-band). This is the piece that goes around your body and is actually responsible for providing 90 percent of the support when you wear a well-fitting bra, Wakefield-Scurr says.

Start by making sure it stays in position, she says. When you try on the bra, first make sure you latch it to the loosest hook—this will extend the life of your garment as you’ll be able to get a snugger fit as the fabric gives with wear and tear. Then, lift your arms and move around: If the band rides up your back, the bra is too small. 

If the bra passes this test, pull the band out, away from your side. If you can pull it more than 2 inches (5 centimeters), it’s either too big or too stretchy and not the right style of bra for you. 

A well-fitting band should feel snug but comfortable, Goldstein says, but what that means will depend entirely on you. “What feels like pinching to someone may feel right and snug to somebody else,” she explains.

Adjust the straps 

Just like eyebrows, boobs are sisters, not twins. Breast asymmetry is common and Wakefield-Scurr says 97 percent of all pairs are unequal in size, volume, position, or form. This is why it doesn’t make a lot of sense for you to try to adjust your bra straps at the same height and expect your breasts to be level. 

Since every body is different, you’ll have to adjust the straps until they look and feel right for you, keeping in mind that they shouldn’t dig into your shoulders. 

“It’s like a backpack—the more weight you have on the front, the more you need to put that waist strap on,” Goldstein says. “So, if you feel [the bra straps] digging into your shoulders, it means your band needs to be snugger.”

When you finish, double-check each strap’s length by pulling it up at the top with your thumb—you don’t want a gap of more than 2 inches (5 centimeters).

Don’t let the cups spill

The most challenging part of finding a well-fitting bra is getting the cup size right. 

Start by making sure all of your breast tissue is in the cups. You can use the good ol’ scooping technique: once the bra is on, slip your hand into the cup and use it to lift and scoop your breast to the front. Or you can get a little help from the force—not the one you’re thinking about, Star Wars fans. 

“You want to put a bra on while leaning over: gravity takes your breasts naturally and makes them go to the center,” Goldstein says.

Once the bra is on correctly, stand up straight and pay attention to the very edge of the cups. If your breasts are spilling out, the cups are too small; if there’s a gap, they’re too big. 

While you’re at it, if you’re wearing a bra that separates the breasts, make sure the separator sits flat on your sternum. If it doesn’t, you may need to try a bigger cup size. 

Goldstein recommends choosing cut and sewn bras (made from fabric pieces that, as their name suggests, are cut and sewn) over molded models made with pre-shaped foam. The latter types, she explains, do not adapt as well to the body and its movements, so it’ll always be harder to find a great fit.

Underwires are your friends—no, really

A lot of people have sworn off underwire bras after getting poked and even outright stabbed by these sneaky pieces of metal. This usually happens with bras manufactured with cheap fabrics that are incapable of holding the wire in place and preventing it from digging into your flesh when you least expect it. 

But both Goldstein and Wakefield-Scurr say underwires are actually useful and help provide the support you need, especially if your breasts are on the larger side of the spectrum. To make sure you buy the right size, Wakefield-Scurr suggests making sure the underwire is not sitting on any breast tissue. 

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“The best place to check that is under the arm—push in the underwire and if it hits bone, then you’re in the right place,” she explains. “If it hits squishy or sort of fleshy tissue, then it’s probably sitting on breast tissue.”

You should also make sure the wire sits flush against the root of each breast, Goldstein says. This is right where your boobs and your abdomen meet.

You’re not a size—you wear a size

Because of their particular structure and the cyclical nature of our bodies, breasts are changing all the time, so you should probably make peace with the fact that the search for the perfect bra might not actually be a goal, but an ongoing adventure. 

It’s a good idea to have a couple of different-sized bras at hand to make sure you’re comfortable throughout your menstrual cycle, especially the two weeks prior to your period when breasts tend to increase in size and become more tender. Then, when your period is over, you can go bra shopping, knowing your hormones won’t be there to ruin the fun. 

Despite what the fashion industry, advertising, and societal pressure may say, remember that sizes exist so we can find garments that fit our bodies—not the other way around.