The fixed admission rule, as it applies to F-1 students and J-1 exchange visitors, will follow this general formula:
Your legal stay will be based on your Form I-20 or Form DS-2019 program end date, or four years, whichever is earlier. You will also be given a “grace period” of 30 days (for both F and J visa holders).
Example 1: You are an F-1 student and your I-20 was issued for a two-year program from September 1, 2026 - May 31, 2028. When you enter the U.S., your I-94 will fix your legal stay to May 31, 2028 plus 30 days, or June 30, 2028. That would be your deadline to depart the U.S. or to apply for an extension of stay.
Example 2: You are a J-1 student and your DS-2019 was issued for five years, from September 1, 2026 - May 31, 2031. When you enter the U.S., I-94 will fix your stay to four years ending around August 31, 2030. You would need to contact ISSS no later than early 2030 to talk about extension options, if you need more time after that.
Please keep in mind that each time you enter the U.S., you will receive a new Form I-94. You should check your I-94 after each arrival, since it can change.