Bra Sister Sizes: Here is a Secret Every Woman Should Know

Bra Sister Sizes

Bra Sister Sizes: Here is a Secret Every Woman Should Know

Argh! I swear I cannot find a bra that fits me. Have you told yourself this sometime back? If so, you probably don’t know about bra sister sizes. Learn what bra sister sizes is and why you should know your sister sizes.

Shopping for clothes is easy; you simply need to check if the dress or pant you want fits you. However, when it comes to bras, things are not as simple as they may seem.

Many women struggle to find fitting bras, and it is not entirely their fault. I mean, with manufacturers following different sizing nomenclature, how are you supposed to know your true size? Why can’t there be a standard bra sizing nomenclature for all of us to follow?

To find a fitting bra, you have to consider various factors such as your cup size, band size, and the unique shape of your breasts.

You already know that these factors are rarely a neat single number or letter.

And this is where bra sister sizes come in.

What is Bra Sister Sizes?

Sister sizes refer to bras sizes that are equal in terms of cup volume. The bra sizes may be different but the bras will fit various cup volumes.

bra sister sizes

For example, a 36F (DDD) bra is in the same family as a 42C, 40D, and 38E.

If you are confused at this moment, continue reading as we’ll explain better below.

The main thing to remember is that there is a perfectly fitting bra for you out there. By the end of this article, you should know how to find you perfect bra size.

Most women think that when they find a fitting bra size, they should stick to it. End of story.

On the same note, you may not think that it is possible for someone to wear two different bra sizes; for example, a B cup and a D cup, unless their breast size actually changed (for instance, after surgery).

Well, you are actually wrong.

You can wear different bra sizes, which will fit you perfectly.

Bra sizes work more like ratios. The volume of the cup size usually determines the band size. Generally, the larger the cup size, the larger the band.

Read on for a better explanation.

Why You Should Know Your Bra Sister Sizes

If you have been struggling to find a perfectly fitting bra, chances are that you are not familiar with bra sister size. If you can’t find a fitting bra, the problem is not with your breasts but with the bra sizes.

However, if you can’t find a bra with a fitting cup or band size, knowing your sister sizes will be very helpful.

How to Calculate Bra Sister Sizes

Here is how to calculate your bra sister size.

Let’s assume that your current bra size band is too tight. In this case, go up a band size but down a cup size.

On the other hand, if your band size is too loose, go down a band size and a cup size up.

This sounds complicated but is really simple. We’ve created a handy sister bra size calculator that you can use below.

Bra Sister Size Chart US

wpDataTable with provided ID not found!

Your current bra size and sister sizes are listed on the same row. For example, if you are a 34D, your sister sizes are 30F (DDD), 32E (DD), 36C, 38B, and 40A.

The sizes in each row are a family of sister sizes.

As you can see from the chart above, an A cup can also be an E cup!

Bra sister sizes can be counterintuitive. However, they are helpful when you are looking for a fitting bra.

For example, if you are wearing a 32E (DD) and the band is too tight, you may think the solution is to go a size up to 34E (DD). However, if you size up this way, you are likely to end up with a bra whose cups are too loose because the sister size of 34E (DD) is 36D. Instead, the next size to try should be 34D, which is the sister size of 32E (DD). With this new size, the cups will still be the same but the band will be better fitting.

Finding a Fitting Bra with Sister Sizes

Here are some tips on what you should do in specific scenarios:

  • The band fits but the cups don’t. If the cups feel big, go a cup size down. If they feel too tight, go a cup size up. For example, if the 34C cups feel small, size up to 34C ½ . If the 34C cups feel big, size down to 32B ½.
  • The cups fit, but the band doesn’t. If the band does not fit, you will have to adjust it as well as the cup size. When going up a band size, you have to go down the cup size, and vice versa. For example, a 38B is the same as a 40A.
  • Both the cup and band don’t fit. In such as case, go up a band size if the band is too small or go down if the band is too big. You do not have to worry about changing your cup size, as it will naturally adjust with the band. For example, if a 34D is too small, go up 36D.

Bra sister sizes also work with half-cup sizes. For example, if you are a 34B ½ , you are also a 36A ½ and 32C ½ . Since these bras have the same cup size, you should look at their band to find one that fits you best.

Now that you know how bra sister sizes work, there is no reason for you to be wearing an ill-fitting bra.

Share this article with your friends to help them find their right bra sizes.


Editor's Recommended Articles

Jeanette is a certified professional bra fitter. Originally from Lyons, France, Jeanette moved to Houston, TX to head the Brabbly content team. When not talking about bras and underthings, she's usually tucked in her study writing a sci-fi novel.

Leave a Reply

Your email address will not be published. Required fields are marked *

Shopping Cart0

No products in the cart.