i had to post because my quest to find one that fits and is comfortable is neverending.
i've tried nearly every suggested method i can find. i've been fitted at victoria's secret 3 times -- 2 stores, 3 people, 3 results. (btw, none of those fit and felt comfortable no matter what style i tried.)
i just know that all that "add 5 inches" business is bullshit. so far, all band sizes i'ved tried with a number larger than my rib measurement have been too big.
as i'm typing this and conducting further research, i just stumbled upon an article in a student magazine for a university in canada.
if you want to have a look, it's in volume 11, issues 3 and 4.
it mentioned a method and a calculator at afraidtoask.com, which i tried because she complained about them yielding different results. i just wanted to see if it was still screwy since it was written over a year ago. the instructions tell me 38c, but the calculator says... 38g. after measuring my ribs again, i decided to add an allowance...just in case. so i added another inch. instructions: 40a. calculator: 40ddd/f. there's no way in hell they'd fill a 40ddd.
anyway, it did mention a method developed by a plastic surgeon named edward pechter. the link in the article doesn't work, but i found it here: http://www.breastreduction4you.com/bra_sizing.htm
it still recommends adding 4" for an even rib measurement/5" for odd, but i still don't like that whole idea.
i have hope for his cup size method. i tried measuring the cups from a few bras, and they were pretty consistent with the chart. i also noticed that if i subtracted my bust measurement from rib measurement (rounded up to 34") using the standard charts to determine cup size, i'm on the larger end of the cup size... the same cup size i come up with using pechter's method. i'm going to give that a shot, but stick with my rib measurement for the band size... now i just need to find a 34ddd.