It depends in where you go and how much time you are able to dedicate to it. You could get a Bachelors Degree in 3 years if you take
summer session. Many Universities offer a 1 year Masters Degree and a PH.D usually takes an additional 2-4 years, depending on how good your research is. You could have it finished in 6 years if you dedicate yourself to nothing but studying 24/7 for 6 years, it ...