To take admission in IIT Kharagpur you have to appear for JEE Advanced Exam.

In order to be eligible for JEE Advanced you have to qualify for JEE main exam first.

To be eligible make sure you should have 75% marks in your boards exam or you should be in top 20 percentile.

For ST/SC you should have 65% marks. 

JEE Advanced maximum marsk are not defined

Maximum Marks vary every year like below:

2017- 366

2016- 372

2015 - 504

2014 - 360

So, it is difficult to predict marks as exam pattern and marks change every year but you should score more than 50% marks to get good branch in Top IITs

Good Luck!!