How to Measure Your Bra Size

A few simple tips will help you find the perfect bra for your body.

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The right bra is one that fits perfectly—but fit is no simple science in the bra world! The wrong bra can ruin an outfit while the right bra isn’t noticeable. It is really easy to wear the wrong bra size, but it can be difficult to realize the size is not the right fit for you. Let’s break it down.

How To Tell You’re Wearing The Wrong Bra Size:

  • Your straps fall often. If this can’t easily be fixed by adjusting the straps, it’s time to look for a new bra.
  • You can slide a few fingers under the band of your bra. You should only be able to slide one finger under your bra’s band, otherwise the band is probably too big.
  • You’re spilling out of the cups—on the bottom, on the sides, on top, if you are experiencing serious spillage, you need a bra with a larger cup size.
  • The cups pucker, meaning they don’t look completely full. It’s easiest to see this if you put a fitted shirt on over your bra. If this happens, you probably need to go down a cup size.

 

How To Measure Yourself:

We recommend finding an expert to measure you instead of measuring yourself, but this is a great place to start if you don’t have the time or proximity to the lingerie section of a department store or other intimates-focused shop. Shopping for bras online can be really tricky, so make sure you understand the return policy before you purchase!

In order to measure yourself, you’ll need:

  • Soft measuring tape or a string
  • Mirror or friend
  • Your best-fitting non-padded bra with underwire
  • Basic arithmetic (or a calculator)

Step 1: Determine Your Band Size

Using a soft measuring tape, measure the circumference of your band which is directly under your bust. Essentially, this is the circumference of your rib cage. When measuring, make sure the tape is parallel to the ground so that it is level. Round to the nearest whole number. If that number is odd, round up to the next even number.

Step 2: Measure Your Bust

Wearing a non-padded bra, measure the circumference of your body around the fullest part of your bust. Using a mirror or a friend, make sure that the tape is level while you are measuring. Your arms should not be included in this measurement. Round to the nearest whole number. Remember your bust measurement, because here is where things can get tricky!

Step 3: Calculate Your Cup Size

Using both your band and bust measurements, you can decipher your cup size. Take your bust measurement and subtract your band measurement to find the difference between the two. Once you determine the difference between bust and band, use the chart below to determine your cup size. For each inch, the cup size goes up by a letter.

Ex: If your band measurement is a 42 and your bust measurement is 45 inches, there’s a difference of 3 inches. That 3-inch difference determines your cup size is a C.

Use this chart to determine your cup size. Keep in mind that every bra manufacturer has their own unique size charts and not every brand uses this method to size their bras, however this is generally accepted as the industry standard.

 

Sister Sizing:

Just like how some pairs of jeans can fit differently—even pairs in the same size from the same brand!—bras too are unique. Trying on is crucial! If you aren’t comfortable in the size that you’ve calculated, try on some bras in sister sizes. Your sister size is another bra size that is close to your size that you have measured.

Here’s how sister sizing works:

  • Try a cup size up and a band size down
    • Ex: If you wear a 38DD, give a 36DDD a try.
  • Try a band size up and a cup size down
    • Ex: If you wear a 38DD, give a 40D a try.

 

Want to see a bra fitting in action? Check out our episode of Dear Ashby on Facebook Live in which Dia Stylist Ashby talked with a bra expert to find her size and learned about the various forms of shapewear. Ready to find a sports bra with the support you need? Check out our Sports Bra 101 post.