Hey for getting into IITs you first need to crack the JEE MAINS examination and qualify for the JEE advance. And the usual cutoffs for qualification into JEE advance in JEE mains exam for general category are 88 percentile in 2019, 85 marks in 2018 and 75 marks in 2017. And you need excellent ranks in JEE ADVANCE to get into software engineering fields in IITS. So hoping that you are from general category, IIT BOMBAY had cutoff rank 63, IIT DELHI 93, IIT Kanpur 213, IIT khadagpur 283, IIT Roorkee 412, IIT Gandhinagar 1548, IIT Patna 2617, IIT Bhubaneshwar 2088, IIT Jodhpur 3110.

So basically to be on the safer side, you need rank in top 3000 ti get into IITs software engineering. And to get even better colleges, you will need 300 and lesser ranks.

Refer to this site for more detailed information..

https://engineering.careers360.com/articles/iits-cutoff-for-b-tech-computer-science-and-engineering

Best wishes. Thank you.