Hi,

To get admission in an NIT, minimum cutoff can be above 97 percentile. To get admission in top NITs like Trichy, Warangal, Surathkal etc., you will require 98.5+ percentile while for the most popular branches like CSE, you may require 99.6+ percentile. 

This year around 9.65 lakh students appeared for JEE Mains.  So, to qualify for JEE Advanced, for general candidates, the overall cutoff percentile can be somewhere between 75-78 percentile.

Also, for admission in IITs/ NITs/ IIITs/ CFTIs, you will need at least 75% marks in class 12th or have to be in the top 20 percentile in your respective board.

Best Wishes.

Hope this helps.

Cheers!