If you are male, it is unlikely that you will experience any growth at all, since these programs are specifically designed to only affect females of age 18 or older, and only if the woman consciously wants to increase her breast size.

If you are female, 18 years old or older, and you consciously want to increase your breast size, the observed rule of thumb for how much growth a woman's breasts can achieve using this program will be as follows:

If she starts off as a D cup or larger, she will usually gain 0 to 1 cup sizes.
If she starts off as a C cup, she will usually gain 1 cup size.
If she starts off with a B cup, she will usually gain 1 or 2 cup sizes.
If she starts off with an A cup or smaller, she will usually gain between 1 and 3 cup sizes.

The smaller the breast size a woman starts off with, the more likely she is to have the natural capacity to increase her breast size. Not every woman will have the natural capacity to increase her breast size, as her breasts may already be at their maximum capacity for size.