I Hated (and Avoided) Bra Shopping for Years. Then a Fit Expert Taught Me This

All products featured on Glamour are independently selected by our editors. However, when you buy something through our retail links, we may earn an affiliate commission.

As someone who has practically made having big boobs she didn’t want her personality, I ought to know how to measure bra size, what cup size I wear, or, quite frankly, how to shop for the bras I need. Alas, I do not. I sized out of Victoria’s Secret before I turned 12. So while my peers had the formative experience of being (relatively) properly sized by an unfriendly sales associate with a tape measurer at the mall, I was told to shove my somewhere-around-F-or-G-cups into a DD and hope for the best.

My approach to bra shopping hasn’t evolved much since: It’s a “hoping for the best!” situation even two decades later. Though honestly, it was working relatively fine until my breasts changed size again this year. (Apparently this happens every so often from either weight gain or loss or, I don’t know, the wind blowing a bit too mightily.)

Determined to grow as a person—and fit my hopefully now dormant breasts into a bra—I set out investigate, and ultimately write, how to properly purchase bras once and for all. In doing so, I’ve learned my undergarment ineptitude isn’t uncommon—and neither is my complete and utter contempt and disdain toward having to shop for them. Mostly for the obvious reasons, like lingering body shame and trauma from yesteryear’s dressing rooms, but also because it’s unusually difficult to find straightforward resources on the subject.

I’d like to change that. Ahead, see everything you need to know about shopping for bras, from how to measure bra size to finding your breast type, courtesy of undergarment experts.

How often should I check my bra size?

You’d think that we’re done growing as adults, so we shouldn’t keep needing to buy new bras. But the truth is, everyone’s body, and therefore breasts, are constantly changing and evolving. “There really is no ‘final’ breast size, as bodies change constantly, especially female bodies,” Nicole Bonello, owner of Fitgame Apparel, tells Glamour. “You might wake up one day and feel a slight gaping in the bra you usually wear, and you might wake up another day and find that you have some spillage from the top of the cups of this same bra.”

What’s more, over the longer term, such things as hormonal changes, weight gain, weight loss, and surgery can also affect bra size and breast shape. “This might mean that you should buy the same size but need a different style to better suit your needs,” Bonello continues. “Due to the changes mentioned, it is recommended that people get fitted by a professional at least once per year.”

How long do bras last?

Bras have a shorter lifetime than one might think. “With respect to bras, most will have a lifespan of around six to nine months if you use the same ones consistently,” says Bonello. “This is because the elastic in the band and the straps will start to deteriorate and become looser over time.”

That’s why Bonello recommends that new bras fit you on the loosest hook and eye setting, unless you’re pregnant or a teen (and therefore still growing). “As you use it over time and start stretching out the elastic, you can then use the tighter hook settings to make full use of your bra,” she says. “Proper hand washing and having a rotation of bras that you can use will of course give you a longer lifespan.”

How to measure bra size

Experts universally suggest being fitted by a professional, which you can have done at department stores like Macy’s, Saks, JC Penney, or Nordstrom, or specialty lingerie and bra stores in your area. If that’s not possible, you can purchase bras from sites that offer virtual fittings.

“I recommend buying bras from a website that offers you virtual fittings with a fitting expert, so you can make sure you get that same professional experience you get in a store,” says Charly Rhodes, brand manager for BoodyDoo sports bras. “If virtual fittings aren’t your thing, use their online resources such as videos or how-to guides to check if your new bra fits correctly.” You can get fitted online with brands like Bravissimo, Curvy Kate, and Wacoal, and find fitting resources on BoodyDoo, Fitgame Apparel, and The Rack Shack.

If you need to measure at home, that’s okay too: Just know that traditional way of doing so, which is known as the “under-over” method, isn’t always exact. “This is a very basic way of getting your bra size, as it will mostly underestimate the cup size you need,” Bonello explains. “That’s why I would recommend that you measure while wearing your best-fitting noncompressive bra that also doesn’t add to your volume.” This way, you’re more likely to receive results closer to your final size, which is especially important if you have pendulous breasts.

Soft Tape Measure

Perfect Body Tape Measure

Once you’ve identified the ideal bra to wear for measurement, find a flexible tape measure and prepare to take two sets of measurements: Under, or your band size, and over, which is your full bust. “First measure under, which is around your ribcage underneath your bust,” says Rhodes. “The tape measure should sit taut and straight across but without digging in as you breathe in normally.” Note this measurement down; it’s your band size.

Next, take the over, or bust, measurement. “The over measurement is taken a bit higher up, this time around the fullest part of your bust. Again, note this down in inches.”

From there, you can either use an online bra calculator, or calculate it yourself by subtracting the band measurement (or under) from the bust (or over) measurement. The number you get should correlate with your cup size, while your band remains your band size. The larger the number, the larger the cup you will need.

In the United States and Europe, the numbers correlate with the following cup sizes: 0=AA; 1=A; 2=B; 3=C; 4=D; 5=DD; 6=F; 7=FF; 8=G; 9=GG; 10=H; 11=HH; 12=J.

In British sizing, the numbers correlate with the following: 0=AA; 1=A; 2=B; 3=C; 4=D; 5=DD; 6=E; 7=F; 8=FF; 9=G; 10=GG; 11=H; 12=HH.

Does that mean you’ve found your definitive bra size? Not exactly (more on that below). “It’s not an exact science, as different bra brands fit differently, but it can give you a starting point,” Rhodes clarifies. “Ideally, do this during a virtual fitting appointment so you can get support and guidance from a fitting expert.”

How to know if a bra fits

When trying new bras, you want to check the fit on the three main anchors of a bra: the band, the cups, and the straps, says Rhodes. “Before assessing, you want to put the bra on properly, on the loosest set of hook and eyes, and do the ‘swoop and scoop,’ where you lean forward slightly and swoop your breast tissue into the cups, one at a time, to make sure no breast tissue is sitting under the band,” she says.

Next, check the fit of the band. “It should be firm but comfortable; you should be able to slide two fingers under the band without much resistance. If it is too tight, go up a size (e.g., from 34 to 36); if it is too loose, go down a size (e.g., from 34 to 32),” she says. “Your breasts should fill the cups without any gaping or overspill. If your breasts are spilling out of the cups, then go up a size (e.g., from C to D), if there are visible gaps or wrinkling of the cups after the swoop and scoop, then go down a size (e.g., from C to B).”

Finally, consider the straps. “Adjust them so there is one to two inches of give if you gently pull upwards from the shoulder with your fingers underneath,” Rhodes suggests. “If you regularly suffer from back pain, or indentations and red marks on your shoulders, from the straps, it can be a sign that your band size is too big and the straps are taking the weight of your breasts.”

Finding the best bra for your breast type

Now that you have a ballpark for your bra size, you’re almost ready to find your bra soulmate. But not quite yet! “It’s hard because every brand fits really differently and every bra shape is different, so it doesn’t only come down to size, per se,” Laura Henny, owner of The Rack Shack, a boutique bra and lingerie shop in Brooklyn, tells Glamour. “There are many aspects: If you have narrow breast roots, you need something with narrower wires with deeper cups. If you have wider breast roots, you need something with wider wires and shallower cups.”

Some people also have closer breasts, meaning they need something with a lower gore, which is the middle part between the breasts where the wires meet. “If that’s too high for some people, it’s very uncomfortable because it pokes them,” Henny explains. “There are a lot of other aspects, so I always recommend doing a deep dive on what kind of breast shape you have and calculating your size.” Don’t worry: Both Boodydoo and The Rack Shack have entire guides on breast shape.

In the meantime, Bonello offers some very basic guidelines for breast shapes and corresponding bra types: “If you’re full on top, it’s best if you wear balcony or fuller cup styles. Plunge styles might not be very good for you because you might fall out of them at the top, even if they’re in your correct size,” she says. Don’t know if you’re full on top? The Rack Shack defines this as “being blessed with natural Bridgerton boobage.”

Freya Idol Underwire Balconette Bra

$70

Chantelle Everyday Graphique Full Lace Plunge Underwire

$76

“If you’re full on the bottom, it’s best if you wear styles like balcony and plunge bras. You might not fill out fuller cup styles, so you might have some wrinkling or gaping in the cup in these styles if in your correct size,” Bonello continues. “If you fluctuate a lot, or have asymmetric breasts, try a bra with stretch lace or mesh at the top of the cup as this will stretch to accommodate your shape better.”

Cuup The Plunge Mesh Bra

$68

Fitgame Apparel Empower Bra

$38

The same goes for sports and high-impact bras. “The band is where 80% of the support comes from in a bra, so it is crucial that you get this fitting correctly in your sports bra so it gives you the support you need for high impact activities,” says Rhodes, who suggests Panache Women’s High Impact Underwire Sports Bra and Freya Lingerie as ideal options for fuller busts. Fitgame Apparel also made their sports bras with larger busts in mind.

Panache Ultimate High-Impact Underwire Sports Bra

$75

Elomi Kintai Full-Coverage Mesh Underwire Bra

$66

Finally, if you’re someone with a smaller back and very large breasts—or very wide breast roots (as in, they sort of start in your armpit)—Henny suggests bras from Ewa Michalak, which are custom made, and Elomi.

See? Buying bras doesn’t have to be so bad, now does it? (This is me talking to me.) Happy shopping!

Danielle Sinay is the associate beauty editor at Glamour. Follow her on Instagram @.