Hello,

Yes. The 10th and 12th marks matter for admissions in IIM Ahmedabad. The most important criteria for getting shortlisted is your CAT percentile. The 10th and 12th marks matter for getting shortlisted from the selected candidates.

10th marks ( A ) :

1. If you got more than 90% in 10th std., you will get rating score 10.

2. If you got percentage in the range 80% to 90% , you will get rating score 8.

3. If you got percentage in the range 70% to 80%, you will get rating score 5.

4. If you got percentage in the range 60% to 70% then you will get rating score 3.

5. If you got percentage in the range 55% to 60% then you will get rating score 2.

6. If you got percentage less than 55% then you will get a rating score 1.

12th Marks ( B ):

The rating scores for Science stream student is same as that of rating scores of 10th.

For Commerce Stream candidate,

1. If you got score more than 90% then you will get rating score 10.

2. If you got score in the range 75% to 90% then you will get rating score 8.

3. If you got score in the range 65% to 75% then you will get a rating score 5.

4. If you got score in the range 55% to 65% then you will get a rating score 3.

5. If you got score in the range 50% to 55% then you will get a rating score 2.

6. If your score is less than 50% then you will get a rating score 1.

After 10th and 12th, the percentage of Bachelor's degree and your years of experience are also taken into consideration and like the ratings given on percentage range of 10th and 12th, ratings on the basis of range of Bachelor's degree percentage and no. of years experience are given ( C & D respectively )

And finally, your overall rating is calculated as A + B + C + D and further you are shortlisted.

Best Wishes.

The following facts will clear your doubt:
A) 2 IIMs (IIM Ahemadabad and Shillong) give 0% weight age to Acads +Work Ex
B)2 IIMs (IIM Calcutta and Lucknow) give 7-8% weight age to Acads +Work Ex
C)4 IIMs (IIM Ranchi, Raipur,Udaipur and Shillong) give 11-15% weight age to Acads +Work Ex
D)3 IIMs (IIM Kozhikode, Rohtak& Trichy) give 17-20% weight age to Acads +Work Ex
E)2 IIMs (IIM Bangalore and Indore) give 47-50% weight age to Acads +Work Ex
Beside these FMS Delhi , MDI Gurgaon , SP Jain Mumbai ,NITIE , MICA , IMT Ghaziabad also take CAT scores.

it really depends on your CAT percentile (and of course GD+PI later on). but when it'll come down to the wire, where they will have to choose between a normal chap and an IITian with a 90+ SSC and HSC; sorry to say, you (we) might end up disappointed.
REASON: mainly because of the stiff competition, a lot of students get par the 99 percentile barrier and the when the stakes are so high even the most minute things make a big difference - which includes your background acads which unfortunately can't be altered.
MY SAY: don't focus on these stats, focus on one and only one thing - CAT, because if you don't get a good CAT percentile, nothing will save you from the cut - not even your star studded history.