the cutoff generally varies from college to college and is different for every specialization, below mentioned link shall specify opening and closing ranks for each IITs and NITs.

https://engineering.careers360.com/articles/jee-advanced-cutoff

However, the following factors shall determine the cutoffs.

1.Total number of applicants for JEE Advanced 2018

2.Total number of questions asked JEE Advanced paper

3.Difficulty level of the examination

4.Performance of the candidates in the test

5.JEE Advanced previous years’ cutoff trends

Students with ranks more than 15000 also do have chances to secure seats in newer IITs with less preferred branches.