On a 15-question test, each question is worth 6.67% of the grade. Miss 1 and the score is 93.3%; miss 2 and it is 86.7%. A passing grade of 60% (D−) allows up to 6 wrong answers, and an A needs at least 14 correct.
How many you can miss for each letter grade
Each row shows the lowest score that still earns that letter on the standard scale, and the most wrong answers allowed to stay there on a 15-question test.
| Letter grade | Minimum % | Correct needed | Most you can miss |
|---|---|---|---|
| A | 93% | 14 / 15 | 1 |
| B | 83% | 13 / 15 | 2 |
| B− | 80% | 12 / 15 | 3 |
| C | 73% | 11 / 15 | 4 |
| D | 63% | 10 / 15 | 5 |
| D− | 60% | 9 / 15 | 6 |
| F | 0% | 0 / 15 | 15 |
Full 15-question grading chart
Every wrong-answer count from a perfect paper down to zero correct, with the percentage rounded to one decimal place and the matching letter grade.
| Wrong | Correct | Percentage | Letter grade |
|---|---|---|---|
| 0 | 15 | 100% | A |
| 1 | 14 | 93.3% | A |
| 2 | 13 | 86.7% | B |
| 3 | 12 | 80% | B− |
| 4 | 11 | 73.3% | C |
| 5 | 10 | 66.7% | D |
| 6 | 9 | 60% | D− |
| 7 | 8 | 53.3% | F |
| 8 | 7 | 46.7% | F |
| 9 | 6 | 40% | F |
| 10 | 5 | 33.3% | F |
| 11 | 4 | 26.7% | F |
| 12 | 3 | 20% | F |
| 13 | 2 | 13.3% | F |
| 14 | 1 | 6.7% | F |
| 15 | 0 | 0% | F |
What a B and a passing grade look like here
On the standard scale a B runs from 83% to 86%, which on a 15-question test is 13 or more correct — at most 2 wrong. The lowest passing grade in most US schools is 60%, a D−, which needs 9 correct, so missing more than 6 questions drops the paper to an F. Colleges often require a C (11 correct here) or better for a course to count toward a major or prerequisite.
Different scale or partial credit?
This page uses the standard A–F scale with whole-question scoring. For strict or lenient thresholds, half or quarter points, or bonus questions, open the grade calculator and set the total to 15. To compare the percentage ranges for every letter, see the US grading scale.