How to Measure Your Bra Size: A Step-By-Step Guide

Did you know that 70% of women are wearing the wrong bra size? It’s true! Finding the right size can be confusing, but it’s essential for both comfort and confidence. Wearing the wrong size can lead to discomfort, poor posture, and an unflattering silhouette.


In this guide, we’ll show you two simple ways to measure your bra size—by using our Bra Size Calculator or following a few easy manual steps. Whichever method you choose, we’re here to help you get the support you need to feel comfortable and confident all day long!

Method 1: Use BOOMBA's Bra Size Calculator

 

If you'd rather skip the manual steps, try our easy-to-use Bra Size Calculator! All you need to do is input your underbust and overbust measurements, and we'll calculate your perfect bra size for you.


HOW TO MEASURE YOUR UNDERBUST
in.


HOW TO MEASURE YOUR OVERBUST
in.


YOUR BOOMBA SIZE:

US = EU = UK = FR/ES = IT = AU/NZ =
RESET


This tool takes out all the guesswork, ensuring that you get the most accurate fit without doing any math. Perfect for those who prefer a quick, reliable answer!


 

 

Method 2: Measure Manually at Home



What You Need

 

    • Tape measure
    • The best-fitting non-padded wired bra
    • Pen and paper to write down your measurements

     

    How to measure your bra size correctly

    Step 1: Find Your Band Size

     

    Wrap the tape measure snugly around your rib cage, directly under your bust. Be sure it’s not too tight or too loose. Round this number to the nearest whole number.

     

    • Example: If your underbust measurement is 31 inches, add 1 inch to determine your band size.

     


    Step 2: Measure Your Bust Size

     

    Next, measure around the fullest part of your bust, typically across the nipple line. Keep the tape parallel to the floor, and ensure it rests comfortably on your skin—not too tight, but not too loose either.


    Step 3: Calculate Your Cup Size

     

    Subtract your band size (from Step 1) from your bust measurement (from Step 2) to determine the difference. Use the chart below to find your cup size.

     

    Example: If your bust size is 38 inches and your band size is 32 inches, then 38 - 32 = 6. According to the chart, a 6-inch difference means you’re a DDD/F cup.

    DIFFERENCE (INCHES) CUP SIZE
    less than 1 AA
    1 A
    2 B
    3 C
    4 D
    5 DD/E
    6 DDD/F
    7 G
    8 H
    9 I
    10 J
    11 K
    12 L
    13 M
    14 N
    15 O
    16 P
    17 Q
    18 R

    Note that this chart uses US cup sizes.

     

    Now, combine your band size with your cup size. For example, if your band size is 32 and your cup size is DDD/F, your bra size is 32DDD/F.

    How to Choose the Right BOOMBA Size

     

    Now that you know your bra size, selecting the correct size for your BOOMBA inserts is a breeze! Simply refer to our chart below, and don’t forget to size up if you’re in between sizes to ensure the perfect fit with our inserts.

     

    BRA SIZE

    US BOOMBA
    BRA SIZE
    SIZE
    CATEGORY
    28A AA X-Small
    30A AA X-Small
    32A AA X-Small
    34A A X-Small
    36A B Small
    38A C Small
    40A D Medium
    42A E Medium
    44A F Medium
    28B AA X-Small
    30B AA X-Small
    32B A X-Small
    34B B Small
    36B C Small
    38B D Medium
    40B E Medium
    42B F Medium
    44B G Large
    28C AA X-Small
    30C A X-Small
    32C B Small
    34C C Small
    36C D Medium
    38C E Medium
    40C F Medium
    42C G Large
    44C H Large
    28D A X-Small
    30D B Small
    32D C Small
    34D D Medium
    36D E Medium
    38D F Medium
    40D G Large
    42D H Large
    44D I Large
    28DD/E B Small
    30DD/E C Small
    32DD/E D Medium
    34DD/E E Medium
    36DD/E F Medium
    38DD/E G Large
    40DD/E H Large
    42DD/E I Large
    44DD/E J X-Large
    28DDD/F C Small
    30DDD/F D Medium
    32DDD/F E Medium
    34DDD/F F Medium
    36DDD/F G Large
    38DDD/F H Large
    40DDD/F I Large
    42DDD/F J X-Large
    44DDD/F K X-Large
    28G D Medium
    30G E Medium
    32G F Medium
    34G G Large
    36G H Large
    38G I Large
    40G J X-Large
    42G K X-Large
    44G L X-Large
    28H E Medium
    30H F Medium
    32H G Large
    34H H Large
    36H I Large
    38H J X-Large
    40H K X-Large
    42H L X-Large
    44H M X-Large
    28I F Medium
    30I G Large
    32I H Large
    34I I Large
    36I J X-Large
    38I K X-Large
    40I L X-Large
    42I M X-Large
    44I N X-Large

    BRA SIZE

    US BOOMBA
    BRA SIZE
    SIZE
    CATEGORY
    28J G Large
    30J H Large
    32J I Large
    34J J X-Large
    36J K X-Large
    38J L X-Large
    40J M X-Large
    42J N X-Large
    44J O X-Large
    28K H Large
    30K I Large
    32K J X-Large
    34K K X-Large
    36K L X-Large
    38K M X-Large
    40K N X-Large
    42K O X-Large
    44K P XXL
    28L I Large
    30L J X-Large
    32L K X-Large
    34L L X-Large
    36L M X-Large
    38L N X-Large
    40L O X-Large
    42L P XXL
    44L Q XXL
    28M J X-Large
    30M K X-Large
    32M L X-Large
    34M M X-Large
    36M N X-Large
    38M O X-Large
    40M P XXL
    42M Q XXL
    44M R XXL
    28N K X-Large
    30N L X-Large
    32N M X-Large
    34N N X-Large
    36N O X-Large
    38N P XXL
    40N Q XXL
    42N R XXL
    28O L X-Large
    30O M X-Large
    32O N X-Large
    34O O X-Large
    36O P XXL
    38O Q XXL
    40O R XXL
    28P M X-Large
    30P N X-Large
    32P O X-Large
    34P P XXL
    36P Q XXL
    38P R XXL
    28Q N X-Large
    30Q O X-Large
    32Q P XXL
    34Q Q XXL
    36Q R XXL
    28R O X-Large
    30R P XXL
    32R Q XXL
    34R R XXL
    28S P XXL
    30S Q XXL
    32S R XXL
    28T Q XXL
    30T R XXL
    28U R XXL

    How to Know If Your Bra Fits Correctly

     

    Once you’ve found your size, it's important to make sure your bra actually fits. Use this checklist to double-check the fit:

     

      • Straps: They should rest comfortably on your shoulders without digging in.
      • Band: It should be snug but comfortable, with enough room to fit two fingers underneath.
      • Underwire: The underwire should sit flat against your rib cage without poking or lifting away.
      • Cups: The cups should fully encase your breasts without any spillage on the sides or over the top.

    Conclusion

     

    Finding your perfect bra size doesn’t have to be complicated. Whether you prefer using our Bra Size Calculator or measuring manually, we’ve made it easy to discover the right fit. Once you know your size, shopping for bras becomes a lot more fun and less of a hassle!

    Ready to shop? Explore BOOMBA products today and find your new favorites. If you need any help, don’t hesitate to reach out via email or DM—we’re always here to assist!