Test Grade Calculator & EZ Grader
Grade a test or quiz in seconds: enter the total and the number wrong to get the percentage and letter grade — or print a full grading chart for the whole class.
A test grade is (correct ÷ total) × 100. If a test has 40 questions and a student gets 6 wrong, they answered 34 correctly: 34 ÷ 40 × 100 = 85%, a B on the standard US scale. Each question on a 40-question test is worth 2.5 percentage points.
How to use the test grade calculator
- Enter the total number of questions or points on the test.
- Choose what you are entering — the number wrong (points lost) or the number correct (points earned).
- Type the number. The percentage and letter grade appear instantly.
- Use the grading chart below the result. It lists every possible score, and you can switch to half-point steps for partial credit.
- Print the chart to keep beside your stack of papers.
Test grade formula
Worked examples
- 25 questions, 4 wrong: 21 ÷ 25 × 100 = 84% (B). Each question is worth 4 points.
- 50 points, 7.5 points lost: 42.5 ÷ 50 × 100 = 85% (B).
- 18 questions, 2 wrong: 16 ÷ 18 × 100 = 88.9% (B+).
- 120-point exam, 102 earned: 102 ÷ 120 × 100 = 85% (B).
Sample EZ grader chart: 20 questions
| Wrong | Correct | Score | Letter |
|---|---|---|---|
| 0 | 20 | 100% | A+ |
| 1 | 19 | 95% | A |
| 2 | 18 | 90% | A− |
| 3 | 17 | 85% | B |
| 4 | 16 | 80% | B− |
| 5 | 15 | 75% | C |
| 6 | 14 | 70% | C− |
| 7 | 13 | 65% | D |
| 8 | 12 | 60% | F |
The calculator builds this chart for any total from 1 to 500, in whole or half points.
For teachers: fast, fair grading
- Weight questions fairly. If some questions are worth more, grade by points rather than by questions — enter the total points and points lost.
- Partial credit. Choose half-point steps to include scores like 17.5 out of 20.
- Curving. A simple curve adds the same number of points to everyone; a more common approach scales scores so the top score becomes 100%. Decide on the method before you return papers.
- Record the raw score. Keep the number correct as well as the percentage, so you can re-grade if a question is dropped.
For students: what does this test do to my grade?
One test is usually part of a weighted category. Once you have your percentage, enter it into the weighted grade calculator to see its effect on your class grade, or the final grade calculator if it is your final.
How many questions can you miss?
This quick reference shows the most questions you can get wrong and still reach each grade (standard US scale: A− 90%, B− 80%, C− 70%, D 65%).
| Questions on test | For an A− (90%) | For a B− (80%) | For a C− (70%) | To pass (65%) |
|---|---|---|---|---|
| 10 | 1 | 2 | 3 | 3 |
| 20 | 2 | 4 | 6 | 7 |
| 25 | 2 | 5 | 7 | 8 |
| 30 | 3 | 6 | 9 | 10 |
| 40 | 4 | 8 | 12 | 14 |
| 50 | 5 | 10 | 15 | 17 |
| 100 | 10 | 20 | 30 | 35 |
Grading on a curve
A curve adjusts scores after a test, usually because it turned out harder than intended. The three common methods are:
- Flat curve: add the same number of points to every score — for example +5 if the class average was 5 points lower than expected.
- Highest score to 100%: multiply every score by 100 ÷ highest score. If the top score is 92%, an 80% becomes 87%.
- Bell curve: set grade boundaries by the class distribution (for example the top 10% receive an A). This is less common in schools and is announced in advance when used.
Whichever method is used, apply it to the raw scores and then convert to letters — this calculator handles the conversion from raw score to percentage and letter grade.
Frequently asked questions
How do I calculate a test score percentage?
Divide the number of correct answers (or points earned) by the total number of questions (or points), then multiply by 100. 34 out of 40 is 34 ÷ 40 × 100 = 85%.
What is an EZ grader?
An EZ grader is a chart or slide-rule that lists the percentage for every number of wrong answers on a test of a given length. Teachers use it to grade a stack of papers quickly. This calculator generates one for any test length.
How many questions can I miss and still get an A?
On the standard scale an A starts at 93% (or 90% for A−). On a 50-question test you can miss 3 questions for 94%; on a 20-question test you can miss 1 for 95%. The chart shows the cut-off for your test.
How much is each question worth?
Divide 100 by the number of questions. On a 25-question test each question is worth 4 percentage points; on a 40-question test, 2.5 points.
Can I grade with partial credit?
Yes. Enter points instead of questions and choose half-point steps. For example, 7.5 points lost out of 50 gives 85%.