The band size being 30 shows that you are a smaller girl, but the cup size being a B means that you definitely do have breasts that aren't small- they are more like medium size.
Is 30C cup size big?
For example, a 30C is actually quite small as its sister sizes would fit a popular size of a 32B cup and a 34A cup.
What size is a 30A bra?
Alpha Size UK & IRE Size EU Bra Size
---------- ------------- -----------
XS 30A 65A
XS 30B 65B
XS 30C 65C
XS 30D 65D
Is 32A or 32B bigger?
The letter is the cup size starting with A, and getting bigger from there, so 32B is a bigger cupped bra then a 32A.
What bra size is the same as 30A?
Is 30D the same as 34B?
However, a 34B is also equivalent in cup volume to a 30D, 32C, and a 36A. All three aforementioned sizes are a B cup despite what their cup letter indicates. This is called sister sizing.20 Feb 2019
What is a 28DD equivalent to?
A 28DD cup is like a 32C or 34B cup size - it's the band that's smaller. A DD cup would probably not appear “small” on a 28-inch chest. Based on those measurements, your cup size would appear more full in proportion to your frame.