First you have to graduate from high school, and that takes 12 years of schooling. Then you have to go to pre-pharmacy school. Many pre-pharmacy schools require you to have a bachelor's degree prior to being accepted at their school. Other pre-pharmacy schools only require some prior college coursework. Pre-pharmacy school can take as little as a year if you already have a relevant bachelor's degree in math or science. Pre-pharmacy school will take about two years if you did not get a relevant bachelor's degree prior to being accepted. After pre-pharmacy school, you will need about four years of more focused coursework and and internship, which are likely to be done simultaneously to some extent. The total years needed after high school varies. I would say two years at a university working towards a science major plus two years in pre-pharmacy school plus four years of focused coursework and the internship equals an average of about eight years after high school.