The cut off marks for various courses are released by the universities and colleges. You can calculate the cut off with the help of your marks in 12th boards. Keep an eye on the cut off list released by the college you are interested in to stay up to date.

Here's how you can calculate the cut off :
4 core subjects are considered each evaluated out of 200 marks.
4 * 200= 800 marks in total (which is further converted to 100 marks).
Divide marks of each subject with 8 and add all of them together to get a final mark out of 100.

Good luck.