Hello,
Cut off is given in terms of closing rank and opening rank for each category and branch.In 2019 the round 6 cut off was follows for SC home state category for various branches
It is difficult to give the exact percentile.But according to the number of candidates appeared in JEE Main January 2020 session you need to score 90-95 percentile to get such rank as in 2019 round 6 cut off rank.But cut off changes in 2020 depending on number of candidates appeared, seats available in each branch etc.
Please try our JEE main knockout program
https://learn.careers360.com/knockoutfull-jee-main-april/?icn=JEE_Main_knockout&ici=c360_sticky_qna_engineering
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile