I’m guessing that most people are familiar with the standard components of a bra size (at least in Canada & the US – I don’t know international sizes). There’s band size – a number, ostensibly in inches (e.g. 38) that represents the circumference of the ribs below the breasts, and there’s cup size – a letter or string of letters (AA, A, B, C, D, DD, etc*) which is based on the difference between the band size and the circumference around the broadest part of the breast (generally right over the nipples).

I needed some new bras and since it had been a long time since I had bought any, I figured I’d get sized. I went to Victoria’s Secret (since I assumed they’d know what they were doing) and they did the standard measuring. I picked out some bras I like (I prefer “T-shirt style” – no visible seams + underwire).

 

They’re torture.

 

The problem is that those two degrees of freedom, band & ‘cup’ don’t adequately cover all possible shapes, especially where there’s an underwire.
We also need ‘radius’.

Radius

Let’s say we have two people with the same circumference under the breasts & across them. Let’s also say they aren’t clones, and actually are shaped fairly differently:

Note that the underwire curve of each person is rather different.

Different underwire curves

These are not the same

So guess what happens when we don’t take that into account when building bras?

It’s 2015. We can do better.

*interestingly, some schemes stop adding new letters at D and just keep adding more Ds, (i.e. DDD=E, DDDD=F)