How a test grade is worked out
The score is the share of the test answered correctly, written as a percentage.
score % = (total − wrong) ÷ total × 100
- Take the number wrong away from the total to get the number correct.
- Divide the number correct by the total.
- Multiply by 100 for the percentage.
- Match the percentage to the letter scale: 90 and up is an A, then 10 points per letter down to F below 60.
Worked example — A 20 question test with 3 wrong: 17 ÷ 20 × 100 = 85%, which is a B.
Common test scores
| Questions | Wrong | Score | Letter grade |
|---|---|---|---|
| 10 | 1 wrong | 90% | A |
| 20 | 3 wrong | 85% | B |
| 25 | 5 wrong | 80% | B |
| 30 | 4 wrong | 86.67% | B |
| 40 | 7 wrong | 82.5% | B |
| 50 | 12 wrong | 76% | C |
| 100 | 15 wrong | 85% | B |
Swipe the table sideways to see the rest.
Percentages are rounded to two decimal places.
Things to consider
- For tests with uneven marks, enter points instead of questions.
- Half marks work: enter 2.5 wrong on a 40 point test.
- Some schools use plus and minus grades or a different scale. The percentage stays the same either way.
- The grading chart below lists every whole number wrong, ready to mark a stack of papers.
Frequently asked questions
How do I work out a percentage grade?
Divide the number correct by the total and multiply by 100. 17 out of 20 is 85%.
What letter grade is 85%?
On the common scale used here, 85% is a B. A is 90% and up.
Do all schools use this scale?
No. Grading scales vary by school, state and country. Some use plus and minus grades, others use bands like HD, D, C, P. Check your school's scale.
Can I enter the number correct instead?
Yes. Switch to Number correct and the calculator works out the number wrong for you.
Does it work for points, not questions?
Yes. Enter the total points available and points lost, including half points.
Results are estimates for general information only, not financial, medical or professional advice.