Hey aspirant, A proper marks to percentile conversion is not available but you can get to know the rank you can expect at this percentile.

At this percentile, your expected rank will be about 87 thousand.

You can calculate your marks from the student responses released by NTA before the release of percentile result. Use the response sheet and find out your marks.

You can find the Correct answers for the Set you have given easily on the Internet.

Hope you will understand.

the percentile cannot be said purely on the basis of marks, but on the basis of the overall difficulty of paper and how other students have answered with respect to your performance.Maybe in a year, 90 percentile comes out to be at 135 and in next year, it comes out to be 180. So, its not possible to judge in that way. But i can assure you that a score of 180 or above is considered to be good.