80% of Moms Get Their Daughter’s Training Bra Size WRONG. How Can You Find the Right Fit?

80% of Moms Get Their Daughter’s Training Bra Size WRONG. How Can You Find the Right Fit?

We get it! Getting your daughter’s first training bra is a big step—an exciting, emotional milestone in your girl’s growth and development. Maybe you knew it was time. Maybe your tween took the initiative to ask for some shopping help. No matter how it happened, chances are that one of you doesn’t feel quite ready.

Well, the mother-and-daughter duo behind Her-Rah! Bra is here to help.

McKenna Hopla founded Her-Rah! after a disappointing first bra shopping experience, and her mother, Carole, has been by her side every step of the way. These girl bosses want all tweens and teens to have the best possible first bra (and have fun finding it)—and that means getting the best possible fit. By following the training bra fitting guidelines below, you can make sure your girl feels comfortable, confident, and fully supported.

Before you begin shopping for your daughter’s first bra, you need to find your daughter’s bra size.

Trying on bras in a store’s changing room can feel … weird. McKenna still remembers how embarrassed she felt when she had to show the changing room attendant the training bras she wanted to try on. (It was a boy!)

To minimize cringe factor and narrow your focus, know your girl’s bra size before you go to the store. This requires taking some very specific measurements in some potentially sensitive places.

Before you break out the measuring tape, make sure your daughter understands that everyone grows differently and has their own unique shape. No bra size is preferable to another! It’s completely common for breasts to grow at different rates, even from each other! Whatever that measuring tape tells her is totally normal.

Band and cup sizes don’t measure maturity or fitness level or beauty or weight. They only say what size bra will feel better on her body.

  1. Measure her rib cage to find her best band size.
    Wrap a measuring tape around her rib cage right where a bra would go. Keep it even all the way around. Pull it snug but not tight. How many inches? If you are between inches, round UP.

    Take that number and add 4. If your daughter has a 28-inch ribcage, she will probably feel best in a 32 band. If she has a 30-inch ribcage, see how a 34 band feels.
  1. Measure her breasts to find her cup size.
    Same deal as the rib cage—only this time, move the measuring tape up around the fullest part of her breasts. Once again, if she is between inches, round UP.

    Now it’s time for some math. Subtract your daughter’s rib cage measurement from her breast measurement. The difference between these two numbers will tell you her target cup size:
  • 0” = AA
  • 1” = A
  • 2” = B
  • 3” = C
  • 4” = D
  • 5” = DD

If your daughter had a 30” rib cage and measures 31” across her breasts, she is an A-cup.

Even if your daughter measures as an AA, she may still need a training bra to support her during early breast growth. It really helps that tingly, stretchy-skin feeling to have extra protection and support.

  1. Put them together to find your daughter’s standard bra size.
    Is she a 28AA or a 32B? Knowing before you go shopping lets you focus more on colors, fabrics, and styles she finds appealing.

    Many bralettes and training bras do not use standard cup and band sizes. They use XS, S, M, L, and XL. Some of these bras will have a chart on the packaging to give you a better idea of how they compare. For others, you may need to guess—and grab a few to try on!

Take a moment to have a talk about how bodies come in all shapes and sizes, and how we only see a very few of those shapes and sizes in popular media. If you are going to a lingerie store, your daughter may look nothing like the models shown on displays and advertisements—and that’s okay! We should all focus on looking in the mirror and loving what we see.

When you shop for your daughter’s first training bra, know a good fit when you see it.

Ask your daughter to think about how easily a particular training bra was to put on or take off. Get her to move and stretch a bit with the training bra on. And it can be helpful to bring a close-fitting top or tee to put on over bras she is considering so she can get a sense of how much coverage and support a particular bra provides.

Let your daughter know that different brands, bra styles, and fabric choices make a HUGE difference in how bras fit. For instance, did you know that most black bras run smaller than their stated size? Sizes are kinda … relative. It’s just a funny thing about the clothing industry that all women learn to find their way around.

If your daughter is apprehensive about shopping for her first bra in a physical store, why not order her first bra online? She can try bras on in her own room, ask for your opinion or talk to her friends, and make a decision that feels good to her.

After you buy your daughter’s first bra, check in with her regularly about how it fits.

Girls grow fast at this age. Her body shape can change almost overnight! But don’t try to buy a bigger bra so she can “grow into it.” (This can plant the idea that bigger breasts are better.) Meet her where she is and celebrate the shape she has. And support her completely, through all the excitement and growth ahead!

Your daughter’s bra shopping days are just beginning.

Remember—a training bra is a celebration, not a cover-up operation! Now that you know how your daughter’s first bra should fit, start shopping at Her Rah! Bra to find her a bra she will love.


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1 comment

This was a super helpful article. Even being a big busted lady, my older daughter is developing a little early and I honestly wasn’t quite ready. This helped me figure out sizing and how to talk about it more in depth with her thank you!


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