There is no specific percentile that will get you into IIM Calcutta. But if you want to stay on the safer side you meet to score at least 99.65-99.70+ in CAT. The minimum cutoff required for the general category remained 85 percentile, however, the actual cutoff to get a call remained much higher i.e around 98-99 percentile.
For the final selection, 4 parameters are considered:
CAT score (weightage 30)
Personal Interview (weightage 48)
Point awarded for Academic Diversity at Bachelor’s level for Non- Engineering degree (weightage 4)
Work Experience (weightage 8)
Since you are a fresher you need to work hard for the Personal Interview as it carries the highest weightage.