what marks are needed to get CS in any IIT??
JEE Advanced maximum marks are not defined :
Maximum Marks vary every year like below:
2017- 366
2016- 372
2015 - 504
2014 - 360
So, it is difficult to predict marks as exam pattern and marks change every year but you should score more than 50% marks to get good branch in Top IITs.
Expected cut off for getting IIT through JEE Advanced for 2017 for general category is more than 145.
You can also check the JEE Advanced cut off from the given below link
You are targeting which year for admission?
The exam pattern of Jee advanced keeps on changing year wise so it is quite difficult to predict any marks range but generally it would be better to get more than 60% for top IITs as this will be the safe score for the same.
Also, you can go through the below provided article to know the cut off for Jee advanced 2017 -
Hope this helps!!!
In terms of rank, aim a rank within 2000 to get the top branches in top IITs.
All the best.