F-1 Visa

F visas are the category of visas used by the U.S. Department of State for individuals coming to the United States for the primary purpose of study. The F-1 visa is for the student, and F-2 visas are for the student's accompanying spouse and children, if any.  Visas are issued at the discretion of a consular officer in a U.S. embassy or consulate and entered into your passport. The length of validity of an F visa (i.e. it expiration date) can vary and it will probably not be the same as the end date of your program of study. The expiration date of your visa does not correspond to your permitted period of stay in the U.S. Rather, your permitted period of stay is determined by the program end date shown on your Form I-20. 

Remember that you do, however, need a valid, unexpired F visa to re-enter the United States if you depart during your period of study.  If your F visa has expired and you are returning to the U.S. to continue your studies, you must apply for and obtain a new visa while you are outside the U.S.  You may not re-enter the U.S. with a different category of visa.  Nor may you re-enter under the Visa Waiver Program, which is solely for short-term tourist or business travel. 

While you are in the United States, your immigration status is referred to as F-1 status.