Hello Aakash..

With the result announcement of JEE Main on April 30, JAB has announced the qualifying cutoff of JEE Main for JEE Advanced 2018. Apart from the qualifying cutoff for JEE Advanced 2018, JAB has also released JEE Main 2018 cutoff for admission to National Institutes of Technology (NITs), Indian Institutes of Information Technology (IIITs) and Government Funded Technical Institutes (GFTIs). The JEE Main cutoff 2018 is the closing rank at which admission to a particular B.Tech programme at a particular institute is closed. This means that candidates having a lower rank than JEE Main 2018 cutoff (for a particular course/institute) will not be considered for admission. In other words, candidates have to secure a rank or JEE Maincutoff 2018 which is above the closing rank. It must be noted that the cutoff of JEE Main 2018 is available category-wise, institution-wise and branch-wise and it varies from candidate to candidate as per the institution/programme/category. 

For more detailing you check it: https://engineering.careers360.com/articles/jee-main-cutoff