How to work out 18 out of 20
Divide the score by the total and multiply by 100: 18 ÷ 20 = 0.9, and 0.9 × 100 = 90%.
That means 2 answers were wrong, and each question was worth 5% of the total. One more correct answer (19/20) would be 95%.
Grading chart for 20 questions
| Wrong | Score | Percent | Grade |
|---|---|---|---|
| 0 | 20/20 | 100% | A+ |
| 1 | 19/20 | 95% | A |
| 2 | 18/20 | 90% | A− |
| 3 | 17/20 | 85% | B |
| 4 | 16/20 | 80% | B− |
| 5 | 15/20 | 75% | C |
| 6 | 14/20 | 70% | C− |
| 7 | 13/20 | 65% | D |
| 8 | 12/20 | 60% | D− |
| 9 | 11/20 | 55% | F |
| 10 | 10/20 | 50% | F |
| 11 | 9/20 | 45% | F |
| 12 | 8/20 | 40% | F |
| 13 | 7/20 | 35% | F |
| 14 | 6/20 | 30% | F |
| 15 | 5/20 | 25% | F |
| 16 | 4/20 | 20% | F |
| 17 | 3/20 | 15% | F |
| 18 | 2/20 | 10% | F |
| 19 | 1/20 | 5% | F |
| 20 | 0/20 | 0% | F |
Letter grades use the common US scale (A ≥ 93%, B ≥ 83%, C ≥ 73%, D ≥ 63%, with ± bands). Your school may use different cut-offs.