UK sizing and European sizing use an F-cup, U.S. sizing does not. I know it can be very confusing!
Every brand fits differently, so it is important to be flexible about your size. Fortunately HerRoom has introduced ‘Universal Cup Sizing’, an easy-to-use system making it simple to work out your cup size in any brand, no matter what the nationality! If you are ‘spilling out’ of the cups, it’s obvious the cups are too small: Happily this particular style goes to a GG-cup (D7), so you can go up in the cup as much as you need to for that perfect fit. Judging by what you say I would try a 36G (36D6). Please also refer to Tomima’s 3 Steps to a Fabulous Fit
to help you.
Allison from Phx AZ