First, let's clarify terms. I assume that by "doctor" you mean a physician... an MD or DO. Also, I'm discussing this using US terminology and standards. If you're interested in becoming a physician in Another Country, the rules may be different; in some cases they're very different.
Minimally, about 8 years of actual school are required after high school (we'll discuss what "actual school" means later).
Most medical schools require that you already have a Bachelor's degree before starting, so that's 4 years (at a few places, you can combine the last year of college with the first year of medical school, but this is a special case; it's also possible, if you go to school in the summers and get advanced placement, to finish a Bachelor's in three rather than four years).
Medical school itself is a 4 year program of class and lab work. That, plus the 4 for The Bachelor's, is the 8 years I was talking about. At this point you are officially an MD (or possibly DO), and can use the title "doctor".
However, you can't actually practice medicine. You're required to complete a year of "residency" first. This is low-paid work at a hospital where you get practical training (as opposed to all the theory you've gotten in med school) in a supervised environment.
Only after that can you actually practice medicine on your own. Also, if you're wanting to specialize in an area like pediatrics or oncology or surgery or something like that, expect to spend another 2-4 years of training similar to the residency in that specialty.
So, to sum up:
After graduation from high school, 4 years (college) + 4 years (med school) + 1 year (residency) + 2-4 years (specialization) = overall, at least 9 years just to be a General Practitioner and possibly up to 13 for some specialties. Careful planning can shave a year off of that, by either enrolling in one of the combined programs or just finishing the Bachelor's in 3 years (and, honestly, if you're good enough at schoolwork to even be thinking about trying to get into med school, finishing a Bachelor's in 3 years isn't beyond the realm of possibility).
Very long to go to school
10 years
12 years
200 months
about 8 or 9 years
Any as long as it has the right course to become a doctor; if you are going to become a doctor you need to get into med school however, you do need good grades to get in .
4 years of basic college and 4 years of medical school
yes you have to go yo medical school
To become a doctor, after high school you must go to college, and then go to medical school.
it all depends what kind of doctor you want to be but it can take normally 8-10 years
go to medical school
Becoming a doctor is easy but can take some time. If you want to become a doctor you can go to any high school but have to go to a college that has a degree in doctor.