Marks Percentage Calculator
Add each subject's marks and maximum to get your overall percentage, the per-subject breakdown and the letter grade for each.
How it works
The overall percentage sums every subject's marks and every subject's maximum, then divides. That is not the same as averaging the individual subject percentages unless all the subjects are out of the same total — a subject out of 150 should pull the average harder than one out of 50, and summing first is what makes it do so.
Each subject also gets its own percentage and letter so you can see which one is dragging the total down.
The formula
Overall percentage
percentage = (Σ marks scored ÷ Σ maximum marks) × 100
Subject percentage
percentage = (marks ÷ maximum) × 100
Marks needed for a target
marks = (target % × total maximum) ÷ 100
Worked examples
| Scenario | Working | Result |
|---|---|---|
| 78, 82 and 69 out of 100 each | 229 ÷ 300 × 100 | 76.33% |
| 45/50 and 120/150 | 165 ÷ 200 × 100 | 82.5% |
| The same two averaged as percentages | (90 + 80) ÷ 2 | 85% — the wrong method |
When you'd use it
- Working out your result before the school publishes it
- Checking an aggregate for a college application
- Seeing which subject is costing you the most
- Converting marks to a percentage for a scholarship form
Common questions
Why not just average the subject percentages?
Because subjects with different maximum marks should not count equally. Summing marks and maxima first weights each subject by its size, which is how boards and universities calculate an aggregate.
What if subjects have different weightings?
Set each subject's maximum to its weighted value. A subject worth double can be entered out of 200 rather than 100, and the aggregate will then weight it correctly.
How do I work out the marks I still need?
Multiply your target percentage by the total maximum and divide by 100 — that gives the total marks required. Subtract what you have already scored to see what remains.
Are my grades sent anywhere?
No. Everything is calculated in your browser, so nothing you type is uploaded, logged or stored. There is no account and no record of what you entered.