Hello Aspirant,

As a matter of fact percentile and marks are different and they will vary shift to shift.Percentile means the percentage of students who have scored less than you in your shift.That means you have scored more than 78% students who appeared the exam on the same day and shift with you and not with all the students who appeared the exam.However when the final ranks will be calculated your percentile will be used with respect to all the students who appeared.

For example,A person appeared the exam in a given shift and batch of 1,20,000 students and got 70 percentile. Suppose a total of 14,00,000 students appeared.When his final rank will be calculated it will be calculated w.r.t the 14,00,000 students(total candidates who appeared the exam).

Hope this helped to solve your query

Regards