Hi there!!! Since every year the maximum marks of paper and their difficulty level changes and the cutoff varies every year as well, there is as such no predefined marks on which you can get admission in IITs. Although you can use our college predictor which would give you an idea about possibilities for your admission in IITs. Its link is  https://engineering.careers360.com/articles/jee-advanced-college-predictor/amp

Hope this helps. Best of luck for your admissions.