Can you tell me how long does it take (on average) for estrogen pills to increase breast size?

Male or female?: If you are female you will not generally see a change in the size of your breasts with appropriate medical dosages of estrogen. If you are a transgender male, you may begin to see enlargement of breast tissue within a couple weeks. This can be painful as the tissues stretch, and your growing breasts are likely to be tender, as in an adolescent female. How long they grow depends on dose & you.