Hi

The cutoff would depend on several factors like your category, home state, desired branch etc. Check the link below to get cutoffs according to your particulars:
https://engineering.careers360.com/articles/jee-main-cutoff-for-top-iiits

In the above link, ranks are mentioned. To go from rank to percentile, use the following formula:

rank = (100- percentile)/100 * 9.34 lakhs, where 9.34 lakhs is approximately the number of students who sat for JEE Mains this year.