The highest college degree is generally considered to be a
Doctor of Philosophy (PhD) or other research doctorates like a Doctor of Science (ScD) or Doctor of Education (EdD). These are terminal degrees, meaning they are typically the highest degree available in a given field.
The time it takes to earn a PhD varies considerably, but it typically takes 4 to 7 years beyond a bachelor's degree. Some programs may be shorter or longer, depending on the field of study, the student's research progress, and other factors.