How to work it out
15 ÷ 30 = 0.5
0.5 × 100 = 50%
Divide the score by the total, then multiply by 100. 15 out of 30 means you got 15 of 30 right and missed 15, so each question is worth 3.33%.
18 out of 30 (60%) would move you up to a D−.
Every score out of 30
| Score | Percent | Letter grade |
|---|---|---|
| 30 out of 30 | 100% | A |
| 29 out of 30 | 96.67% | A |
| 28 out of 30 | 93.33% | A |
| 27 out of 30 | 90% | A− |
| 26 out of 30 | 86.67% | B |
| 25 out of 30 | 83.33% | B |
| 24 out of 30 | 80% | B− |
| 23 out of 30 | 76.67% | C |
| 22 out of 30 | 73.33% | C |
| 21 out of 30 | 70% | C− |
| 20 out of 30 | 66.67% | D |
| 19 out of 30 | 63.33% | D |
| 18 out of 30 | 60% | D− |
| 17 out of 30 | 56.67% | F |
| 16 out of 30 | 53.33% | F |
| 15 out of 30 | 50% | F |
| 14 out of 30 | 46.67% | F |
| 13 out of 30 | 43.33% | F |
| 12 out of 30 | 40% | F |
| 11 out of 30 | 36.67% | F |
| 10 out of 30 | 33.33% | F |
| 9 out of 30 | 30% | F |
| 8 out of 30 | 26.67% | F |
| 7 out of 30 | 23.33% | F |
| 6 out of 30 | 20% | F |
| 5 out of 30 | 16.67% | F |
| 4 out of 30 | 13.33% | F |
| 3 out of 30 | 10% | F |
| 2 out of 30 | 6.67% | F |
| 1 out of 30 | 3.33% | F |
| 0 out of 30 | 0% | F |
Letter grades use the common US scale (93 and up is an A, 90–92 an A−, and so on, below 60 an F). Your school or teacher may use a different one.