Dear Kirit, it depends on what your target Colleges are. If you want to get into IIMs, it should be nothing less than 95%. Other new IIMs might need a percentile of 90. And the cut offs go down further based on the reputation of the College.The basic eligibility criteria remains 50% aggregate for General Category in Graduation and 45% for Reserved Categories or equivalent CGPA from any recognised University. Because CAT exam will be held at different slots, CAT scores will be normalised to ensure equivalence in the difficulty levels of the exams for both slots. IIM Kozikhode will normalise the CAT scores using percentile equivalence. Adjustment of location and scale differences of score distributions across different norms and then scores will be normalised. These scores will be then converted into percentiles for shortlisting and selection purposes. Other than IIMs there are almost 100 Institutions that accept CAT score. Most colleges conduct Written Ability Test and Personal Interview as well. To be shortlisted for this round, your CAT composite score and your Academic track will also be assessed. For example, for IIM Indore, this is the criteria:
10th Standard: 36*[Z Candidate-Z min/Z max- Z min]
12th Standard: 40*[Z Candidate-Z min/Z max- Z min]
CAT 2019 score: 20*[Candidate's overall score /Highest CAT score]
Gender Diversity Factor: = 4 for female applicants
                                                 =0 for other applicants
Composite score= sum of the above scores
Great Lakes, Chennai considers freshers or Candidates with a minimum of 24 months of experience for its PGPM course. And for PGDM, it considers candidates with more than 24 hours of experience. And then your Category comes into picure. So considering all these factors, you shpuld aim at the following percentiles depending on your Category:
General Category: 90+
OBC-NCL: 80+
SC: 60+
ST: 50+
IIM Ahmedabad has a different rating for Commerce Stream
For 12th it is as follows:
Percent Scored              Rating Score
<=50                                                   1
>50 and <= 55                                  2
>55 and <= 65                                 3
>65 and <= 75                                5
>75 and <= 90                                 8
>90                                                   10


For Graduation, the percentage of marks secured will be considered final. If the Institution doesnt grant marks but grants grades or percentages, it will be calculated on the basis of marks obtained in the marks list.

That will be calculated as follows:

Percent Scored                Rating Score
                   
<= 55                                          1

> 55 and <= 60                         2

> 60 and <= 62                         3

> 62 and <= 65                         5

> 65 and <= 70                         8

> 70                                            10