Grading scale for 13 questions
On a 13-question test each question is worth about 7.69% of the score. Subtract the wrong answers from 13, divide by 13 and multiply by 100: with 2 wrong, (13 − 2) ÷ 13 × 100 ≈ 84.62%, a B on the common US plus/minus scale.
The chart gives every score from 0 to 13 wrong. Print it on one page, or switch to your class cutoffs first.
13-question grading chart
Letter scale: Common US plus/minus scale
The plus/minus cutoffs Wikipedia lists for US colleges: A+ from 97%, A 93, A- 90, B+ 87, B 83, B- 80 and so on down to D- at 60. It is not universal, so use your syllabus's cutoffs when they differ. Source: Wikipedia, “Academic grading in the United States”.
| Letter | Lowest % | Remove |
|---|
Each letter starts at its lowest percentage and runs up to the next letter.
Rounding and decimal places
Follow your syllabus. A displayed percentage can round up while the unrounded score stays below a cutoff.
Only changes how results are shown. Extra places appear when rounding would push a score over a letter cutoff.
Wrong answers for each letter: A+ 0 · A- 1 · B 2 · C 3 · D+ 4 · D- 5 · F 6 to 13. No score out of 13 is A, B+, B-, C+, C- or D.
13 questions · Common US plus/minus scale · no rounding before letters
| Wrong | Correct | Score | Letter |
|---|---|---|---|
| 0 | 13 | 100% | A+ |
| 1 | 12 | 92.31% | A- |
| 2 | 11 | 84.62% | B |
| 3 | 10 | 76.92% | C |
| 4 | 9 | 69.23% | D+ |
| 5 | 8 | 61.54% | D- |
| 6 | 7 | 53.85% | F |
| 7 | 6 | 46.15% | F |
| 8 | 5 | 38.46% | F |
| 9 | 4 | 30.77% | F |
| 10 | 3 | 23.08% | F |
| 11 | 2 | 15.38% | F |
| 12 | 1 | 7.69% | F |
| 13 | 0 | 0% | F |
classgradecalculator.com/grading-scale/13-questions
Mark the papers
The easy grader opens set to 13 questions and this chart’s cutoffs: tap once for each wrong answer, save each paper, and it keeps the class average and how many papers earned each letter.
Mark 13-question papersGrading scales checked . Sources are at the bottom of the page.
How each score is worked out
Score % = (13 − wrong) ÷ 13 × 100
Every row uses the easy grader’s formula. Scores show up to two decimal places, and more only where rounding would carry a score over a letter cutoff, so the letter beside a score is the one the unrounded score earns.
A half-right answer counts as half wrong: 2.5 wrong is halfway between the rows for 2 and 3. Type it in the easy grader for the exact score.
Your class cutoffs
The chart starts on the common US plus/minus scale, where an A starts at 93% and an A- at 90%. Choose another scale under “Letter scale”, or type your own cutoffs; the chart, the letters line above it, the printout and the CSV all follow. If your class rounds to the nearest whole percent before giving the letter, choose that under “Rounding and decimal places”.
When questions are worth different points, use the test grade calculator with the points earned and possible instead.