How to Measure Bra Size and Other Bra Shopping FAQs, Answered

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.