Question: When a girl says she’s a small C cup does that mean she actually is a full B? What’s the difference between a small C and a full B cup?
Best Answer: It varies, really. If a woman wants to know her bra size, she measures twice: Once around her rib-cage, and once around the fullest part of her breast. She then subtracts the rib-cage measurement from the breast measurement.
For example: Thirty eight inches around the rib-cage, forty one inches around the breasts – that gives her a three inch difference.
The actual number of a bra size has absolutely nothing to do with your cup size. The number is how many inches around your ribcage you measure. The cup size is the difference that you figured out – one inch difference is an A cup, a two inch difference is a B cup, and a three inch difference is a C cup… it keeps going, obviously). SO really, that would give the example girl a 38C measurement, which is pretty average.
What really makes the difference in a “small C” or a “full B” is the shape of the breast. If the breasts are slightly narrow, the fullest part will still measure out to a C, but the overall diameter might be smaller than the actual C sized cup. Since most sizes go by inches (A cup being one inch, B cup being two, remember, etc.), there can actually be a lot of difference between a full B and a small C. Half an inch can mean a lot when it comes to being comfortable, but some bra lines do offer half sizes for this reason.
Basically, if a girl’s bra doesn’t fit, go to a department store like JCPenney’s. They’ll measure for you. Hope this helped.
I worked at a women’s clothing store for a while, and most of the customers didn’t know their real bra sizes.