The most reliable way I suggest is

1. Predict your rank using any online rank predictors (They give you ranks based on last year's data)

https://engineering.careers360.com/jee-main-rank-predictor

2. Download the cutoff ranks list available on www.kea.kar.nic.in ( http://www.kea.kar.nic.in/ )

3. Compare and know which college you might get.

Good Luck