Percentage is the simplest way to compare marks across subjects and exams. The formula is short, but small mistakes with totals cause many errors.
The basic formula
Percentage = (marks obtained / maximum marks) x 100
Example: you score 438 out of 600.
438 / 600 = 0.73, so 0.73 x 100 = 73%.
Add everything first
When subjects have different maximum marks, do not average the individual percentages. Add the marks and the maximums, then divide.
| Subject | Obtained | Maximum |
|---|---|---|
| Maths | 82 | 100 |
| Science | 70 | 100 |
| English | 38 | 50 |
| Total | 190 | 250 |
190 / 250 x 100 = 76%.
You can enter each subject into the marks percentage calculator and it adds them for you.
Finding the marks you need
Marks needed = (target percentage / 100) x total maximum marks
Example: you want 70% in an exam of 600 marks.
0.70 x 600 = 420 marks.
If you already have 250 marks from earlier papers worth 350 in total, and the final papers are worth 250, you need 420 - 250 = 170 out of 250 in the final papers.
Percentage change
To compare two scores, use:
Change = (new - old) / old x 100
Going from 60 to 69 is 9 / 60 x 100 = a 15% increase. The percentage calculator handles this too.
Common mistakes
- Forgetting to include a subject with a different maximum.
- Dividing by the wrong total, such as 500 instead of 600.
- Rounding too early. Keep decimals until the final answer.
- Mixing a CGPA with a percentage. If your result is a CGPA, convert it using your own university’s rule. See our guide on CGPA conversion.
Classes and cut-offs
Many boards label 60% and above as first class and 75% and above as distinction, but cut-offs vary. Always check the official rules of your board or university.
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