Dear Aspirant,

It is not possible to predict the exact situation as it depends on the number of students attempting the exam the preferences of the students and the seat matrix of the college.

There are 1300 seats in IISERs reserved for IAT Candidates and about 130 of them are reserved for EWS candidates.

Usually if you have a rank below 500 you have a really good chance of getting into IISERs.

With a category rank of 869, you have a small chance of getting into IISER Behrampur or Tirupati in the last or post allotment rounds. Please keep other options open.

Check out the link below for more details.

IISER cut-off

Hope this helps.