hello Welcome to careers360!

you can check your Jee rank using following tool

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

or you can visit

https://engineering.careers360.com/articles/how-calculate-jee-main-2019-rank-based-on-nta-percentile-score

The approximate formula for calculating your rank is

((100-your percentile score) *1150000) /100

This is the formula used for careers360 rank predictor tool by considering total appearing number of students equal to 1150000.

This will be only an approximate Prediction. 

Hii

The rank list for JEE Mains has not been declared by NTA Yet, but you can use the following formula to calculate your expected rank-
100 - your score * total students appeared /100
Here total students of january session are 874469.
So as per the above formula you can calculate the expected rank but yes please be informed that the rank will vary in the final result as the best of two scores would be used and also the no. of students will increase.
So you need to wait for final results for any confirmation.
You can also use the careers360 rank predictor tool, again this also does not guarantee the confirmation but is just for the reference purpose.
here is the link for the same-  https://engineering.careers360.com/jee-main-rank-predictor

Hope this helps
Feel free to revert back for any more doubt.
THanks!!!