(I have created a percentile calculator updated every year (updated to CAT 2023. that can be accessed publicly. You just need to enter your credentials and it will tell you the percentile you need to get a call : Percentile Calculator. An NA implies that it is not possible to get a call, unless you're in the top 50 of your stream. Please note that these will give you a ballpark estimate, as they are based on historical data. Just download the file using save as and enter your credentials to know what you need to score)For starters, the various shortlisting criteria are available online for IIM Ahmedabad, IIM Bangalore and IIM Calcutta.Every institute has these shortlisting criteria for which they select candidates for interviews. Every institute has a minimum application score you must clear to make it to the interview shortlist.The institute that you graduate from also no bearing, except the scaling that the IIM's do with the CGPA. Most good institutes have their CGPA's unchanged, some are scaled down/up marginally.IIM Ahmedabad:The application rating cutoff this year for candidates who were not stream toppers** was .72. The application rating consists of a scaled maximum of .3 from pre CAT (10th, 12th, Undergrad) and a scaled maximum of .7 from the CAT (refer to application rating). So your pre CAT application score would be 40.5 (exactly as much as mine) and your scaled contribution to the application rating would be .27, leaving .72-0.27 = .45 for the CAT to cover. (0.45/0.7)*450 = 289.3 ~ 290 to be on the safe side. This would come to be a percentile of 99.5 to get an interview call assuming you are a not a stream topper.**From this year, IIM A has tweaked their PI shortlisting to be more inclusive. As mentioned in their application rating, you can get a call if you are amongst the top 50 of your background. Here, the application rating cut-off isn't considered and you are given a direct interview call. If you aren't in the top 50, you must clear the application rating.IIM BangaloreI wasn't able to find an online version of their PI/WAT shortlist cut-off criteria, but because they include work experience and have a good amount of weightage to their pre CAT I personally do not know anyone below a 99.75 who got a call with these credentials (assuming you are a fresher). I am also aware that they are very strongly inclined to high acads for graduation. (An important point has been pointed out by Aditya in the comments)IIM CalcuttaAn important thing to note is that they do not take your CGPA into consideration (woot for everyone who screwed up theirs!).IIM Calcutta had its cutoff as 69.96. Taking in your credentials and assuming you are a male candidate you would need 69.96 - 20 = 49.96 (out of 77) of the CAT Score which works out to 292/450 which would be 99.62 percentile. (Refer to the application rating). The cutoff is also present hereMy .02$ : Score as much as you can. Being in the 'safe zone' never works. Work hard. Score well. A very high percentile will open all interview doors to you. And the interview is really important.