Hi Ayush,

It is not possible to calculate the exact rank from given percentile so there is a formula for calculating near about rank which is given as below

(100 - your percentile) *869010/100

According to this formula your rank would be around 15,700. According to the last year's trend there are little bit chances that you may get CSE branch in NIT Patna.

I would suggest you to appear in second attempt of JEE-Main exam in month of April. You should score above 99 percentile to get confirm chances of CSE branch in NIT Patna.

You can use JEE-Main College Predictor to predict the college according to your percentile and category.

I hope this answer helps you.

All The Best!!