Hello Aspirant, The opening and closing ranks for various NITs and IIITs vary each year depending upon the no. of students appeared each year, seat availability, difficulty level, etc.

You can see the previous years cutoff trends of various NITs given below ,

https://engineering.careers360.com/articles/nits-cutoff-for-top-btech-branches

And for the cutoff trends of various IIITs use the following link,

https://engineering.careers360.com/articles/jee-main-cutoff-for-top-iiits

Good luck