Add the marks of all subjects
Divide the total marks by the total maximum marks
Multiply the result by 100
Use the formula: Percentage = (Total Marks Obtained ÷ Total Maximum Marks) × 100
If CBSE asks for best 5 subjects, add the marks of the best 5 subjects only
Divide the best 5 total by 500 if each subject is out of 100
Multiply by 100 to get the percentage
Example: If total marks are 450 out of 500, percentage = (450 ÷ 500) × 100 = 90%