I would like to tell you that unlike previous years, this year the cut off would be based on the NTA score which is a percentile measure of the students’ performance.

JEE Main 2019 Cut-off of Total NTA Score Based on Paper-I for JEE Advanced 2019

• Common Rank List-89.7548849
• Economically Weaker Section (EWS)-78.2174869
• Other Backward Class (OBC-NCL)-74.3166557
• Scheduled Caste (SC)-54.0128155
• Scheduled Tribe (ST)-54.0128155
• People with Disability (PWD)-0.1137173

The admission authority will release the cutoff for top B.Tech branches of NITs for the admission of candidates in different NITs through JEE Main. 

Factors determining the NITs cutoff for top B.Tech branches

• Total number of applications received for the admission in the institute
• Total number of candidates appearing for the JEE Main exam
• Number of B.Tech seats available
• The difficulty level of the JEE Main 2019 exam
• Previous years’ cutoff trends

I would suggest you visit the careers360's link given below for detailed info of the cutoff

All the best