Dear aspirant,

It is quite hard to predict mark versus rank scenario for IAT as it depends on the difficulty level of the question paper, number of students attempting the exam etc. Looking at the previous year trends we can say that you have a fair chance of getting IISER Tirupati, Bhopal and Bherampur. It'll be hard the old IISERs like Pune, Mohali but you might have to wait for a few rounds before you can get any sort of idea. So, please keep other options open.

Hope this helps.