And note that Japanese bra sizes run consecutive letters but a little smaller than their US/European counterparts. A Japanese “A” size would overlap an American AA and an A cup and a B would overlap an A and a B. Apparently my ex-wife found this out when we lived in the States.
Depending on the clothing supplier, in Korea it’s the same. Every time I went to Costco in Korea, it cracked me up to see two large tables set up with the same clothing for sale, but one table labeled “Asian Sizes” and the other “Western Sizes”.
… add one cup size for nursing mothers … learned that the hard way …
You win the thread! 
Ref bob++: I’d bet most of the folks with pain are large-chested. Or just plain large. Who would tend to need bras bigger than commonly stocked at the local department store. Hence they’d buy what they could find, right fit or not.
I also suspect nowadays with all the emphasis on boobs shoved well out into public, wearing one too small and so spilling bounteously out the top is a common fashion decision.
Actually they are quite simple:
A = almost there
B = Barely there
C = Cant complain
D = Damn!
On the other hand, if you try on an actual fabric bra and it’s a really comfortable fit, then you can buy one bra. If there’s a standard that accurately reflects the variety of shapes and sizes, and you learn what your size is by that standard, then once you know you can buy as many bras as you want.
Like all women’s clothing sizes, they’re basically made up on the spot by the advertising department to fool consumers, they have no relation to anything else on the rack or in any other store or even by the same manufacturer, and you have to try every single thing on before you buy it because the idea that there are standard sizes is a cruel joke clothing manufacturers like to play on women.
I can’t wait for the metric measures. 
I had heard about bias on the other side. AAs and As are underrepresented in statistics derived from bra sales statistics because “just go without” is a more viable option.
The theory that if you are, say, a 34C you can just wear a 36B by going ‘up a band size, down a cup size’ - is pretty misleading.
The size 36 band would ride up from the size 34 ribcage, where it ought to be, onto lower front and sides of the breast tissue, leaving the elastic around a sensitive area. This is likely to be very uncomfortable. And the cups would be overflowing on all sides.
There’s no doubt women have it worse than men. But if you think men don’t also experience (some) meaningless marketing-driven sizing you haven’t shopped mens’ clothes all that much.
There are three versions, of which the one with two numbers appears to be disappearing:
-
number and letter, where the number is the band in cm.
-
number and letter, where the number is measured over the nipples and in cm. AKA French sizing.
The letters are for cup size and are the same as for people who use inches. -
numbers for great perimeter and band.
So, for example, someone with a 90/75 would have a 75C (cm) or 30C (inches) in bra+cup, and a 90C in great perimeter+cup.
Shocked - I am shocked that nobody has posted one of my favorite Seinfeld episodes regarding this topic.
Well, I buy pants sized in inches for both inseam and waist. I buy shirts sized in inches for the neck and the sleeve. I understand they’re only accurate to within two inches and there’s plenty of other fit problems I can run into that those numbers don’t clarify, but that’s all far better than having an entire outfit called “size 10”, whatever that means. Bras are supposed to be more objectively sized, but every woman I have spoken to tells me that is emphatically not the case.
I routinely buy clothes online. I’ve never met a woman who would buy anything more important than socks that way, at least not without a solid free-return guarantee and a month or two in advance of whatever event they needed those clothes for.
Not as complicated as shoe size, which are based on the barleycorn, which is 1/3rd inch. A size 12 is 12 inches and then count back in barleycorns. eg: size 11 is 12 inches - 1 barleycorn - 11.66 inches.
Children size zero is 12 barleycorns = 4 inches and then add a barleycorn for each size, eg: size 1 = 4.33 inches.
I’m having a hard time to think of any marketing-drive pressure that would affect mens’ clothing sizes. It’s not like anyone is ever going to brag about wearing a size L t-shirt or pants with a 36-inch waistband. I suppose there’s some marketing pishposh about whether a dress shirt is “slim-fit” or other subjective description.
So what are you saying; size matters?
You’re both right. “Slim fit” is one current scourge of men’s fashion. I don’t know if you remember the Seinfeld episode where Jerry wears jeans with the waist size printed on the visible label (Levi’s do this in real life, I think), and is caught altering the label to make it look like he still wears the same size as he did in high school, but that’s another example.
Still, pretty slim pickens when compared with the constant deluge of bullshit women have to put up with in the world of fashion.
I referenced it in post #15
I think we all agree they’re pretty amazing- men think so for some reason, babies for milk and women for one of their superpowers (growing humans, making milk… whether you do it personally). “Boobs” is so… denigrating. Breasts are pretty nice and we wouldn’t have survived as a big brained species without an extended period of intense brain growth fueled by mother’s milk.
Anyway… bra fitting is further messed up by complementary sizes. I don’t understand it, frankly so I ignore it. I have a great bra fitter at Nordstrom, she finds a brand that fits (Calvin Klein right now), I buy one or two full price. Then I keep an eye out for them at Marshall’s/TJ Maxx etc since full price is a lot. I wander into other brands but it’s iffier.
Good bra fitting. That’s important.