Hello Shivam,
According to the Round 7 of JoSAA counselling, opening and closing rank of Electronics and Electrical Communication Engineering of IIT Kharagpur (Open category) is
Opening rank- 535
Closing rank- 861
Go through the link below to check the Closing ranks according to your category for all the rounds of JoSAA Counselling to have an idea about the rank you need to score to get admission-

https://josaa.nic.in/webinfocms/Public/View.aspx?page=71

Good Luck!