Hello Aspirant ,

Calculating the percentage  through NAT percentile is not possible. You should wait for the official results to be out.

But there is a simple formula through which we can calculate the approximate rank using NAT percentile.

JEE Main 2019 rank (probable) = (100- NTA percentile score ) X 874469 /100

If NTA percentile score is 90.70, JEE Main rank will be (100-90.70 ) X 874469/100 = 81325

Consider the NTA score of 80.60 then JEE Main 2019 rank = (100-80.60) X 874469 /100. The rank will be 169646.

** This formula would not be for a 100 percentile score as those are the top ranks.

Good Luck!