Hello Aspirant. I hope you have performed well and given your best effort for cracking JEE Mains. Basically, Percentile depends on  candidate's performance as in the percentage of students against whom he/she scored better. For instance, if you have secured 98 percentile then that means you have performed and scored better than 98 percentage of the people who have appeared for a particular JEE Mains session.

Based on previous years' reports and assuming the difficulty of the paper to be moderate, in order to secure 98 percentile, you have to fetch marks somewhere around 160 to 180 (out of 300). Please note this assumption may vary from actual and it depends on the number of students appeared in the particular session of the exam, difficulty level of exam , other students' performance and of course, your performance etc.

If you want to predict tour rank based on your percentile or marks, feel free to use JEE Main 2021 Rank Predictor:

If you want to get detailed report on your eligibility for various streams in different colleges then use JEE Main 2021 College Predictor:

I hope you have got a clear idea.

Thank you and all the best for your future and career.