You can calculate your JEE All India Rank from your percentile by using the formula:

100-your percentile * (no.of Candidates who appeared for the session)/100. And, 869010 Candidates appeared for January session. Going by that,

100-70*869010/100 = 243322 is your All India Rank. With an All India Rank of 243322, a seat in a NIT is difficult even with SC reservation. You have to appear for April session. But to check the possibilities for a seat in other colleges, with this rank, please use our College predictor: