The fallacy of “too big” and “too small”

Boobs are a little more complicated than “small” and “big”.

A fit specialist might tell you to size up for a bra, like getting a baggier T-shirt if the tighter one doesn’t fit right.

The theory behind sizing up goes something like this: an orange might not fit into a martini glass, but it’ll fit into a bowl. So can’t you just size up?

The short answer is: no.

Bras function best when they’re an exact fit. You wouldn’t be very happy if you could only get shoes in sizes Small, Medium, and Large.

If you wouldn’t shove your feet into a general solution, you wouldn’t want to shove your boobs into a general solution, either. Breast tissue is malleable, but your sternum isn’t.

Wait! But we use two parameters, like 34B.

Let’s think about that for a second. The band size parameter, 34, refers to the circumference under the bust. The cup size parameter, B, refers to the difference between your full bust and under bust measurement.

These are all busts that can be classified as 34B. In these diagrams, the blue circle measures to 34″ and the pink circle measures to 36″.

Cross-sectional view from top down. Blue indicates under bust measurement, pink indicates full bust measurement, and yellow represents actual breast tissue distribution.

Imagine that we try to put this 34B bra onto them all.

If you happen to match what lingerie brands think of as the median bust, congrats! You’ve hit the bra jackpot. Otherwise…ouch. Remember, purple means metal wire and yellow means soft tissue.

So… why are people talking about bras in terms of one dimension, like “too big” or “too small”?

Why are people even talking about bras in terms of two dimensions, like 34B?

Isn’t the thing… three dimensional? Aren’t YOU a three-dimensional being?

And that’s my problem with bras.

People are complex. Boobs are complex, with a lot of variations along the possible parameters: 1) rib cage angle between top of boob to bottom of boob, 2) rib cage softness, 3) position of boob on rib cage in the vertical axis, 4) position of boob on rib cage in the horizontal axis, 5) separation between boobs, 6) width of each breast root, where it is attached to rib cage anywhere between underarm and sternum, 7) height of each breast root, where it is attached to the rib cage anywhere between collarbone and abdomen, 8) projection of tissue, 9) tissue density, and 10) shoulder width.

In the 1970s, North American bra manufacturers and industry professionals attempted to convene and put a stop to the madness of not having a universal standard. They came away without a system.

Can you guess why?

It’s the same reason why a lingerie store doesn’t have enough stock to address the entire population (and the same reason a pharmacy doesn’t sell prescription glasses). If each of the above 10 variables can be described on a scale of 1 to N, we end up with N^10 bra combinations.

So it turns out that this is a really hard problem.

There are too many boobs in the world, with more variations than two variables can account for.

Even if we could define bra sizes with a bunch of variables like root width and height, how can you collect this data with a user experience that is non-invasive, quick, and accurate? Imagine this: