It may actually depend on the college youre seeking admission into. Check their admission criteria. Generally the best of 5 rule is applicable to CBSE students. But it is still better to check with the college you need. And to be safe account for all your subjects. 

Hello student!

For calcuation of percentage in class 12, you are to count the marks of best 5 and find your percentage. Generally, while taking admission into universities like DU, they take into consideration the marks of your best 4 subjects. So whatever you want to find, select the requisite number of subjects.

Cheers!