Bra sizes

[Itscurtainsforyou]

Why do they fluctuate so much between brands?

I've been having problems with a bravissimo satine bra (underwires digging in) so start to wear an old nursing bra (no wires) while I wait to go bra shopping. The bravissimo bra is 36h and the nursing bra (Royce) is 36j. The band of the nursing bra is too tight (leaves marks)so I concluded that I should be in a 38 band.

Tried some 38s on today and they were enormous. I've ended up with a curvy kate bra in a 36h, which is lovely, but I just don't see how bras in the same size can vary so much.