Remember these 4 points: 0. Visa is just a valid document for travel upto Port-of-Entry. Neither it guarantee entry to the US nor it defines your duration of stay in the US. 1. US visa cannot be renewed inside the US 2. Visa renewal in isn't necessary if you aren't travelling outside the US 3. If your visa has expired and you need to travel outside the US, then you must get new Visa form the consulate in the you are visiting. For F1, your legal Duration of Stay (DoS) is defined by the expiration date of your I-20.