How the score is calculated
Score = correct answers ÷ total questions × 100. If you know the number wrong, correct = questions − wrong. Points earned = correct × (total points ÷ questions), so each question is worth the same share of the total.
The letter grade comes from the unrounded percentage and the scale you choose: the common 90 / 80 / 70 / 60 scale, a plus/minus scale, or your own cut-offs for A to D.
| Grade | From |
|---|---|
| A+ | 97% |
| A | 93% |
| A− | 90% |
| B+ | 87% |
| B | 83% |
| B− | 80% |
| C+ | 77% |
| C | 73% |
| C− | 70% |
| D+ | 67% |
| D | 63% |
| D− | 60% |
| F | below 60% |
Worked example
A 20-question test with 3 wrong: 17 ÷ 20 × 100 = 85%. On a 100-point test each question is worth 5 points, so the student earns 85 points and a B on the 90/80/70/60 scale.
The chart below the result lists every possible number wrong, from 0 to 20, which is handy for grading a stack of papers.
Assumptions
Every question is weighted equally and there is no partial credit. For tests with sections worth different amounts, use the weighted average or grade calculator instead.
Grading scales differ between schools and teachers, so check the syllabus before relying on a letter grade.