Per federal regulations, the program extension must be requested and processed before the end date on your I-20.
Program extensions must be requested no later than 15 business days (3 weeks) before the end date listed on your I-20.
In general, immigration requests are processed in about 10-15 business days (2-3 weeks). It is best to request a program extension at least 2 months before the program end date on your I-20. This ensures that a DSO will be able to process the extension in time. This also allows for any errors, or if you need to submit updated documentation.
Please Note: The SEVIS system will physically not allow us to process a Program Extension after the end date of your I-20 has passed. You MUST request a program extension with plenty of time before the end date of your I-20.