Can someone explain bra sizing to me?

[Elmo311]

Hi all!

I really should know this by now but just need someone to explain it!
I have always worn a 34B bra (for like 15yrs) but recently noticed the bras weren't comfortable so went to get measured. She measured my band size as 32 and got me to try on D, and DD's! They fit really nicely.
So are my boobs bigger or what? I also tried on a few C's which were also a good fit so i am confused!

Thank youuuu (please don't judge me !)

It's about the difference between your back and the fullest part of your bust. A is 1 inch difference, B is 2 etc.

So bigger the cup size usually equals bigger boobs but like a 40B will have bigger boobs than a 30B because the whole body will be different.

People often take their bra size as some kind of identity rather than a measurement and don't change for years, or assume if their bra doesn't fit they've put on weight and need to go up a back size not cup size. So most people wear bras with too big a back size, too small a cup size. Leads to unsupported boobs and possibly pain and looking lumpy!

To complicate matters manufacturers vary quite widely between sizes just like with clothes, so two 32Ds won't always be the same size in practice though they should be in theory. Boobs are also different shapes as are bras, so you might find one manufacturer suits you better.

I'm a HH cup so no choice but to know this crap, I'd be in lots of pain if I didn't!

The actual underbust measurement is the band size. This is the most important bit and were things most often go wrong.

So, say you measure 32 then a 32 is the right size, with an odd number (say 31) you'd try band sizes either side, the smaller of the two is often the best fit.

Cup size is relative to band size rather than being an absolute volume of breast IYSWIM. 1 inch = 1 cup size. A 32 underbust and a 33 over bust would be an A cup - 32A. A 42 underbust and 43 overbust would also be an A cup (40A) but the volume of the cup will be significantly bigger in the 40.

The volume of the cup of a 30d, 32c, 34b and 36a are the same.

There are subtle (and not so subtle) variations between manufactures and styles so (as with clothes) you have to faff about to get the actual best fit.

I put 40 twice where I meant to put 42

Thank you!