Your Cup Letter Is Meaningless!

I said I’d talk about sister sizing, so here I go. Don’t worry if I confuse you; other bloggers have said what I’m saying much more concisely than I probably will, and I’m including links to them.

I want to start with a quiz: What do you think the bust measurement of someone who should wear a D cup is?
A) 32 inches
B) 36 inches
C) 40 inches
D) 44 inches

The answer is…

Super secret answer E) All of the above.  Because all the cup letter tells you is the bust measurement relative to the band size! All that “D-cup” really means is “this person has a bust measurement that is four inches larger than their underbust measurement.” A is one inch, B is two inches, C is three inches, DD is five inches, so on and so forth. By the way, the measurements in the quiz are for 28D, 32D, 36D, and 40D, respectively.   As you can imagine, those are all different sized breasts. A 28D is much smaller, volume-wise, than a 40D. Having trouble picturing this? Check out the galleries at The Bra Band Project.

So, exactly how does sister sizing work, then? Well, it works out that certain cup/band combinations have the same volume. For example, I wear a 32E (usually.) The cup volume of my bra is roughly the same volume as a 28FF, 30F, 34DD, 36D, 38C, 40B…you get the idea. Essentially if you go down in the band, go up in the cup; if you go up in the band, go down in the cup. This is helpful information to know if you come across a bra with a band that’s too tight or too loose. Or if you need a band size that a certain bra is not made in. For instance, a lot of smaller framed woman who need a 28 band or below rely on sister sizing because of the limited availability of smaller bands.

Want to see sister sizing in action? I happen to have a 34E and a 32F of the same bra, the Just Peachy Lace Non-Padded Balconette. The 34E was the first bra that I ordered online when I was figuring out my size. The cup fit basically okay but the band was too loose. Fit alright on the second hook, though, so I kept it and ordered a 32F, too. Take a look at them laid one on top of the other:

The blue one on the bottom is the 34E and the purple on top is the 32F. You can see from the pic that while the 34E obviously has a longer band that the cups are pretty much the same size. The wires on the purple are a little bit shorter, but thats made up for by the fact that the cup is a little deeper. So…roughly the same volume. And the fit is roughly the same in both. (I’ll review those more in-depth hopefully soon.)

Sister sizing isn’t always a viable option. Going down or up can change such things as the length of the wire, the width of the wire (making the cup either wider or narrower), the depth of the cups, the width of the wings (that side panel by the cups), the width of the band as a whole…probably some other stuff that I’m not even thinking of. Sometimes these changes are for the worse. Though, sometimes they can be beneficial.

Another thing I want to address in this post is a phenomenon commonly referred to in the bra world as “letterphobia,” which is basically a term used to describe a reluctance to wear a bra above a certain cup size. I know a lot of people probably look at my pictures and think “she doesn’t wear an E, her boobs aren’t that big at all!” But the people saying that wouldn’t bat an eye if I said I wear a 38C. (Which, remember, has the same cup volume!) This is because so many people have the misconception that cup size is a fixed volume. I know I had that impression. Along with some other wildly inaccurate ideas. You know, unreasonable ideas like thinking that anything above a D had to be veering into Dolly Parton territory (not that there’s anything wrong with large breasts…but that’s a different post.)

One of the (many) problems with those kind of misconceptions is that it messes up correct fit even more. For example, let’s say a woman is wearing a 34C. Let’s even say that’s the right size for her. Suppose she loses some weight and needs to move down to a 32 band. Let’s further assume that the weight loss hasn’t affected her breast volume (highly unlikely, but stay with me here.)  Because of sister sizing, she should move to a 32D. But if she assumes that cup letters are a fixed measurement, she won’t. She’ll buy a 32C. I know she will because I’ve done this. And it’s incorrect.  Granted, if she did lose breast volume as well a 32C might work. (Super Important Sidenote: If your body changes in any way it’s a good idea to re-check your breast measurements. Hell, re-check once in a while just for funsies. Boobs can change.) But I’m thinking that if this hypothetical woman (or, you know, me a few months ago) noticed that her breasts were smaller she’d buy a 32B. Because of the assumption that, well, “I wore a C before and they’re smaller now, so…B, right? B is always smaller than C, across the board, isn’t it.” BZZZT! WRONG!

A big reason why I started this blog is that I hope I can make a small difference on the “helping women feel better about their bodies” front, and I think that a properly fitting bra can be a good step in the direction of a more positive body image. Sounds a little silly, but I really do think that. I also know that a lot of women refuse to believe that they need a different bra and a fair amount of that is tied up in misconceptions (and harmful stereotypes) about certain cup sizes. Hopefully with so many bloggers getting the word out to clear up misinformation all of that will change.

Yeah, I’m still confused…
Read these posts (with helpful pictures) from The Butterfly Collection:
Why Do Cup Volumes Get Bigger As The Band Gets Bigger?
Bra School: Not all D cups are the same size

Or these ones from Braless in Brasil:
D’s just aren’t that big!
Cup sizes are NOT created equally


2 thoughts on “Your Cup Letter Is Meaningless!

  1. Pingback: Review: Wacoal Reveal T-Shirt Bra | Filling A Niche

  2. Pingback: Just Peachy Lace Non Padded Balconette Part 2: 32F | Filling A Niche

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