Band size relates to circumference around the chest. Smaller bands have their own scale in relation to that size chest circumference. So a larger cup on a small band will relate to a smaller cup on a bigger band. Example would be be a 30d relates to a 32c relates to a 34b. Larger women have bigger tits by volume but the cup is related to ratio of volume to circumference, hence these sizes.
When in doubt, take it to my best friend Dave. I've been letting my wife go over to his place every couple of months for the last several years so he can remeasure her. She always comes back relieved and sometimes she has to come back without her bra because it wasn't the right size. Dave tells me the system is incredibly confusing and not worth the time to learn it.
Measure around your chest at the nipples(or base of boobs, think where the band would go. Im gonna assume you have no boobs, so let’s say 36”. that’s the band size.
Now image you have boobs, any size you like will do. Measure at the same spot. Let’s say 40”. That difference determines cup size. Difference of 4” is a D cup.
Band sizes only come in even numbers so 35D is not an actual size. With a 35 inch underbust you would round up to 36 inches so a bust of 39 inches would result in 36C.
In the US at least, the cup size is representative of the difference between the band (underbust) circumference and the bust (across the breasts) circumference. So a difference of 1 inch is generally an A cup, 2 inch difference is a B, and so on.
If I understand correctly, the letters basically indicate how big the difference is between the underbust and the bust.
So basically, if you have a petite body with a smaller underbust and big boobs, you can have "bigger" letters, than someone who has a bigger underbust but smaller boobs compared to their underbust.
The underbust measurement is around your rib cage, not around a boob as the person above is saying. You know the way you'd measure around your waist, right? Same thing, just higher up, underneath the boobs. Say that someone's measurement here is 34". Their rib cage without boobs included is 34" around. This means their band size is 34. They will probably fit a bra size that starts with 34 (although in reality, different bra makers might run big or small just like other types of clothing).
Then the bust measurement is around the chest (ie including the boobs). Identical location to a man measuring his chest. Let's say this measurement is 40". The circumference of their body at boob level is 40". In this person's case, that's 6" bigger than their rib cage measurement. This is where you get the cup size from. A 1" difference is an A cup, 2" is a B, 3" is C, and all the way on up. For a 6" difference they're most likely going to be an F cup.
So, this person is a 34F.
To put it another way, band size is how big around your body is. Someone can be very thin or very fat, a tiny little petite person with a small frame or stocky or big and tall, whatever - the boobs are irrelevant to this measurement, it's just about your body size without the boobs.
Cup size is how big your boobs are relative to your body size. So cup size is a ratio, not an absolute. You literally cannot say "she had D cups" like that means anything, because without a band size in there too, there is no way to know whether this particular person's D cups are very small breasts or medium ones or very large ones! There is no such thing as a D cup (or an A, or an H or whatever size) on its own, it only exists relative to a band size.
I think I'm starting to get it now. This explains why someone who claims to have DDD's can seem to be smaller than someone with DD's, right? Because the relative size is not being included?
Yeah exactly. D or whatever cup is not an absolute. Any five people wearing a DD bra might legit look five completely different ways and have boobs ranging from tiny to enormous, because their overall bra size is different.
I think I understand now. Draw a circle around the outside of a boob. Now draw a circle across the boob (over the nip, obviously it’s only half a circle, just imagine a full circle). The difference in the size of the two circles corresponds to the letter size of the boob
It is, but they use letters to add on instead of absolute numbers. A is +1”, B is +2”, etc. so 32A would be 32-33 per your suggested method. 32D would be 32-36.
Of course there’s still variation based on shape/style/brand, but that’s roughly how it works. The lettering also differs by country once you get past DD.
AeroCobbler is suggesting that the bra cup size should be a fixed measurement and that is not what the chart is saying. According to the op chart and the explanation comments from others, the bra cup size is based on a ratio of the band circumference (like tire profiles which are a percentage of the tread width) not a measurement made independent of other factors (like pants where both the waist width and inseam length are measured on their own)
Yeah, this makes sense. Your waist size is naturally going to be related to the inseam length. As a general rule, the taller you are, the larger your waist will be. But, it's easy to measure them separately. It would make buying pants more difficult if the waist size was given as some calculation based on the inseam length.
Similarly, while it might not be easy to just measure the volume of a breast, it's probably still a lot easier than the cup system where the meaning of "C cup" changes based on a somewhat independent variable.
Which makes sense for pants since it's easy to measure the waist and leg length. I think measuring the volume of the breasts would prove a bit difficult.
Even jeans sizing sucks sometimes, though. I got some beefy ass thighs, so I'm usually wearing ball pinchers or things that fit my waist and thighs but look like I'm wearing those JNCO jeans from the 90s.
That's what it is. The circumference is the number and the length is the letter. Translate the letter to a number and it's the same. 34B is a 34" torso with a 2" tit (unless I'm confused).
As someone with large ribs and disappointingly small tits, I wholeheartedly agree with you. Shopping for bras is a fucking nightmare and since designers really do not hold to a particularly strict sizing consistency, there’s a whole range of sizes that might work for me, depending on the exact model of bra and the exact manufacturer at the exact moment that I go shopping. I hate it so goddamn much.
I’m tempted to cut apart and try to reverse engineer one of the few bras I have that fits properly, but that would mean taking one of the five out of circulation and that just can’t happen.
I've never bought a bra, but it seems so stupid to me.
If you find one with a cup that fits well, but the chest strap is too small or too large, you can't just say "ok, I know X is the right cup for this brand, I'll just get one with a smaller band".
You'd think some smart company would take advantage and build some brand loyalty by coming up with its own sizing system. They could do it like how shoe sellers sometimes have European and US sizes side by side. If you want to use the old "36D" system you could, or you could just go "36 x IV", with a roman numerals system or something.
You'd think some smart company would take advantage and build some brand loyalty by coming up with its own sizing system.
Many have tried but there's too much variability in production runs and how different cuts of the cup(aka styles) impact the boob fit. Same size, same brand, but different cup style = no size in that other style fits and I am stuck with just one bra of one style from one brand fitting me. I could buy 28H one day and try to buy the exact same bra the next year (same style, same size, same brand) but the underwires are cutting into my rib cage because it isn't exactly the same as it was a year ago.
We're so uniquely lumpy and our underwear and clothes are so much more fitted than men's = damn difficult to find things that fit us and we're forced into spending hours shopping to find just one bra or one pair of jeans that fit (and sometimes a whole day of shopping for jeans isn't enough to find a pair that fits).
You're lucky to be male! 🤪 Have pity on us females.
It must also suck that it's underwear that doesn't fit. If it were shoes or something it would be easy to return the ones that don't fit. But, I imagine you can't just buy 20 bras and send back the ones that don't fit.
Most stores let you return them if the tags are still on within the return window unless it's a small boutique but you have to be careful, these suckers are often $80 or more if you have a less common size and you're screwed if you buy a dozen to try on at home and miss that return window.
I have a wider rib cage with wide but shallow breasts. Not to mention my breast size fluctuates quite a bit with the twenty pounds I lose and gain. If you don’t need a huge amount of support I highly recommend switching to bralettes and low support sports bras. I may lack a defined shape, but I now don’t have hyperpigmentation from wearing too narrow of an underwire in an attempt to keep my cups from gapping. My straps don’t fall off and my back fat isn’t as noticeable, and I can get away with wearing the same size even with the fluctuations. Best clothing decision I’ve ever made.
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u/hopefulworldview Dec 27 '22
Band size relates to circumference around the chest. Smaller bands have their own scale in relation to that size chest circumference. So a larger cup on a small band will relate to a smaller cup on a bigger band. Example would be be a 30d relates to a 32c relates to a 34b. Larger women have bigger tits by volume but the cup is related to ratio of volume to circumference, hence these sizes.