So, bra sizes, yeah. A bra size contains two measurements: an around-the-chest measurement, and a cup size. The first is a number, the latter a letter (or letters).
But in foreign countries that don’t use our alphabet, such as China, Russia, and Japan, what do they use to designate cup size? Or are the letters a worldwide standard?
Well, my mom bought me some bras in brazil, and all they say is “44.” Just one number – no cup size – and 44 of what!? I’d like to know. (My USA bra size is 34 B or C)
Warning: I am not a professional bra handler.
Methods of calculating bra size in the US/UK vary a little, but the most common industry measure [AFAIK] is: Measure around the torso just below the bust (in inches). If the measurement is an odd number, then add five inches to obtain the bra band size. If the measurement is an even number, then add four inches. Clearly, the ‘industry’ measurement is imprecise (e.g. it essentially goes in 2" increments); Most manufacturers use a variant. That’s why two different brands of the same size can fit so differently
Each European nation uses its own system(s) but the EU system is fairly common: measure under the bust (unterbrustweite/dessous de poitrine) in centimetres. For many countries (including Switzerland and Germany, where I learned this, shopping for my GF), this measurement is the bra size. In French and standard EU sizing, add 15cm to this measurement (dessous de poitrine + 15cm) to obtain the bra size.
Don’t even get me started on cup sizes. I’ve never seen a Europe/US chart that looked entirely satisfactory across the entire range. Fortunately, most people, myself included, get by nicely by simply memorizing the handful of relevant measurements [pun? What pun?]