Dear Sophie, it is very difficult to be specific about cup size because it is not a precise science. Furthermore, the shape and the profile of the implant are critical in producing the result as a 250cc implant could come in a variety of shapes and profiles and it would depend on the dimensions of your frame and the sort of look that you were trying to achieve as to which shape and profile would suit you. I hope my short video is helpful.Good luck.
The change will vary with the person, but generally a 250 cc implant in a 32A breast would take you to a B or possibly a C cup depending on the bra maker.The final cup size depends on what you start with, what you ad, and who makes the bra.