Hello,

To calculate your 12th Grade percentage, take any 5 subjects and find out your percentage. To calculate best four percentage, you can take any four subjects and calculate the percentage. 

Some colleges may ask you to include all 6 subjects while calculating overall percentage. 

To calculate the percentage : 

Take the sum of the marks obtained in the subjects (4/5/6 subjects), then divide it by the total of those subjects (400 in case of 4 subjects, 500 in case of 5 subjects and 600 in case of 6 subjects) and then multiply by 100.

Hope this helps you.

All the best!

Please do tell in case you have any further queries.