ugh... i may be the worst person to answer that question, because no matter what i cant seem to get any measurements to agree with the most comfortable size!
conventionally, that is usually correct... but make sure you try on to find out what is comfortable!!
yes it's 1 inch for every cup size...unless you are going from a AA cup to A cup, then it's 2inches...like when I started I measured 31 inches at my bust with a 32band size and I had to grow 2inches to get to 33inches to put me at an Acup.
