Becoming an internist takes around 8 to 10 years and in some cases 13 years for completion of all the schooling to become an internist doctor.
Most internist need to complete at least 4 years of undergraduate school and 4 years of medical school to become an internist.
So that schooling alone equals 8 years to become an internist.
And if the internist is specializing in other fields of medicine then they will need to complete between 3 to 8 years of internship and residency programs.
So some internist doctors can complete the schooling and education and become an internist in 8 years while some may need 10 to 13 years to complete the education and get into the specialty that they are working in.