How to Measure Your Bra Size

Bras have a real bad rap, but if you look forward to flinging off your bra the moment you step through the door, it’s possible that the issue isn’t the bra itself, but its fit. A well-fitting bra can be so comfortable that you hardly notice you’re wearing it (seriously) — and on the flip side, an ill-fitting bra that gapes, slips, rides up your back or digs into your back and ribs is quite possibly one of the most irritating feelings in the world.

Whether it’s a strapless bra, wireless bra or sports bra, finding the right fit is the most important step of scoring the best bra for you, regardless of if you’re in the market for a bra for a large bust or the best bra for small busts — fit is equally important for all breasts!

How to find your bra size with measuring tape

Step 1: Find your bra band size

Wearing an unlined, non-padded bra (not over your clothes!) or a fitted t-shirt,run the measuring tape all the way around your back where your band sits, being careful to keep the tape level. “Take a couple deep breaths and make sure the band isn’t too snug — you should be able to comfortably fit two fingers beneath the tape measure,” says Emma Seymour, senior product analyst in the Good Housekeeping Institute Textiles Lab.

If you don’t get a whole number (e.g. 33 and 1/2 inches), or you get an odd number that’s between traditional band sizes (e.g. 33 inches), round up to the nearest whole, even number (34 inches). That number is your band size.

Step 2: Measure your bust

The best way to measure your bust is to run the measuring tape around your back, just under your shoulder blades, and up around the fullest part of your bust. The tape should just skim the bra in front.

Step 3: Calculate to find your cup size

If you’re still wondering: “What is my cup size?” All you need to do is a little bra math:Subtract your band size from your bust measurement to find your cup size. The difference in inches corresponds to your cup size. For example, if your bust measures 37 inches, and your band size is 34, the difference will be 3. On the chart below, you’ll see a 3 is equal to a C cup, meaning your bra size is 34C.

Bra size chart

How to find your bra size without a measuring tape

No measuring tape? No problem! You can easily measure yourself with a household item like “a piece of string or ribbon (just make sure it’s not stretchy!),” says Seymour. “Then, measure your bust and band sizes with the string, and then you can measure the length of the ribbon with a ruler.” As with the measuring tape though, you’ll want to be sure that your string is level and isn’t too snug around your back and bust.

What is a bra “sister size”?

If you’ve measured meticulously, shopped for your breast shape and your bra still isn’t fitting perfectly, you might need to shift your sizing a bit. “A sister size refers to a bra size that has the same cup capacity with a different band size,” says Seymour. “You should opt for a sister size when the cups fit but the band doesn’t,” she advises.

If you try on a bra and the cups fit but the band is too tight, you can’t just go up a band size: “You’ll actually end up with larger cups if you do this,” Seymour explains. “Choose a sister size instead with a larger band for a better fit.” The below chart makes easy work of finding your sister size:

Bra sizing FAQ

What’s the right bra for my breast shape?

Just because you’ve found your correct bra size (yay!) doesn’t mean your work is done (sorry!). If you’re not finding the perfect fit even after measuring yourself, you might be missing an important piece of context: your breast shape. Even if you’re wearing the ‘correct’ size, it might be that you’re wearing the wrong bra for your shape.

Fit is dictated as much by size as it is by breast shape, so you shouldn’t be afraid to try additional sizes from various brands to find the bra that looks the most flattering and feels the most comfortable. Here are some tips to ID your breast shape:

• Round breasts carry fullness all over. For full breasts, our experts recommend triangle or plunge bras that hug breasts without digging in.
• Teardrop breasts mostly carry fullness on the bottom. Try sweetheart demi silhouettes or fabric overlays that keep cups laying flat.
• Compact breasts sit high, and you might find that bras sit away from your body or that lace or fabric doesn’t lie flat. Shop for stretch fabrics or bras with contoured padding.
• Wide-set breasts carry fullness on the sides. Look for bras with gently curving underwires and generously spaced gores (the center part of the bra between cups).
• Asymmetric breasts are different sizes. Look for stretchy, shallow cups or contour styles sized to the larger breast. (Hint: Always shop for the larger breast to avoid telltale spillover.) You can also shop for bras with removable padding to compensate for the smaller side.

• How do I know know if my bra fits correctly?

  • The band sits level all the way around your ribcage without riding up, constricting, or squeezing.
  • The center of the bra lays completely flat against the breastbone. That center piece between the cups is called the gore, and it shouldn’t hover above the chest.
  • The straps fit snugly without digging in. They should be adjusted to fit tightly enough for support, but not so tight that they dig in. Indentations or tired shoulders are a sign they’re too tight.
  • The cups don’t gape or dig into the breasts, even when you move around. Be sure to walk, dance and wiggle around a bit to see how your breasts settle into the cups, and check both the sides and the front for potential spillage.
  • Lastly, raise your arms. If the bra stays in place, then you have found a good fit for you.

  How often should I be measuring my bra size?

  You should be measuring your bra size yearly. This can help you celebrate the body you have and ensure full comfort in your underpinnings. It will also help indicate whether or not it is time to find a new bra.