Quiz Grade Calculator: Turn Quiz Scores Into Grades
Turn quiz scores into percentages and letter grades. Enter total questions and incorrect answers to get correct answers, percentage, and letter grade.
Formulas verified against standard references. Calculator logic tested with verified worked examples. Last reviewed: October 2026. Our methodology
How a quiz grade works
A quiz grade starts from two numbers: how many questions there were in total, and how many you got wrong. Subtract the wrong answers from the total to find the correct answers, then turn that into a percentage.
For a single quiz, this is simpler than a full course calculation. If you want to combine several tests or assignments, use the test score calculator instead.
Formula and worked example
Correct answers = total questions - incorrect answers
Percentage = (correct answers / total questions) x 100
Worked example: a quiz has 20 questions and you got 3 wrong. Correct answers = 20 - 3 = 17. Percentage = (17 / 20) x 100 = 85%. On the standard 10-point scale, 85% is a B.
Standard grade scale and grade table
The calculator uses the standard 10-point scale. Some schools use plus and minus grades or different cutoffs, so always check your course syllabus if your grade looks different.
| Letter grade | Percentage range |
|---|---|
| A | 90-100 |
| B | 80-89 |
| C | 70-79 |
| D | 60-69 |
| F | Below 60 |
Example grades for a 20-question quiz:
| Wrong answers | Correct answers | Percentage | Grade |
|---|---|---|---|
| 0 | 20 | 100% | A |
| 1 | 19 | 95% | A |
| 3 | 17 | 85% | B |
| 5 | 15 | 75% | C |
| 8 | 12 | 60% | D |
| 9 | 11 | 55% | F |
Tips for using your quiz grade
Use the percentage, not just the letter, to see how close you are to the next grade. One more correct answer on a 20-question quiz is worth 5 percentage points, so a single question can move you across a boundary.
To see how a quiz fits into your overall course mark, check the GPA calculator, which combines grades across courses.
Remember that a quiz grade is one result. It does not include homework, participation, or exam weighting unless your teacher counts it that way.
Frequently asked questions
How do I calculate a quiz grade from wrong answers?
Subtract the wrong answers from the total questions, divide by the total questions, and multiply by 100. For example, 20 questions with 3 wrong gives 17 correct, which is 85%.
What is 17 out of 20 as a percentage and grade?
85%, which is a B on the standard 10-point scale.
What percentage is an A?
90% to 100% on the standard scale. Some schools add plus and minus grades, so 90% to 92% may be shown as A- there.
What is the passing grade for a quiz?
Most schools use 60% or 70% as the pass mark, but your teacher or school sets the exact cutoff.
Can incorrect answers be more than total questions?
No. Incorrect answers cannot exceed the total number of questions, and the calculator will show an error if they do.
Does this calculator work for any number of questions?
Yes. It works for any quiz length, from a short 5-question quiz to a long 100-question quiz.
How is a quiz grade different from a course grade?
A quiz grade covers one quiz. A course grade combines many quizzes, tests, homework, and exams, often with different weights.
