F-1 Visa processing time is much shorter than other US Visas such as E-1, J-1, Q1 and M-1.
Most of the times, F-1 visa is processed immediately after your interview.
The interview is the last step of your F-1 visa. By the end of the interview, you will be told if your application is approved or not.
The F-1 visa processing will take around 3 days to a week.