JEE Main OBC category cut off marks to qualify for JEE Advanced for 2017 was 49.

To check the cut off to get NITs/IIITs and GFTIs you can refer below link

JEE Main Cut off

Determining Factors of JEE Main Cutoff 2018

- Number of applications received for JEE Main 2018
-Number of questions asked in the paper
- Difficulty level of the exam
- Performance of the candidates
- Previous years’ cutoff trends of JEE Main

Good Luck!!