Enter how many questions were on the test and how many were wrong. You get the percent, the letter grade and a grading chart for every possible score, like a teacher's EZ-grader.
How a test score is calculated
Score % = (questions − number wrong) ÷ questions × 100
With points instead of questions, it's the same idea: points earned ÷ points possible × 100. Each question is worth 100 ÷ questions percent, so on a 20-question test every miss costs 5 points.
Worked example
A 25-question quiz with 4 wrong: 25 − 4 = 21 right. 21 ÷ 25 = 0.84, so the score is 84%. On the usual scale, 84% is a B. One more right answer (22 of 25) would be 88%, a B+.
The grading scale used
By default this uses the most common US scale. Each letter covers 10 points. With plus and minus grades on, the top 3 points of each band get a plus and the bottom 3 get a minus.
| Letter | Percent | Letter | Percent |
|---|
| A+ | 97–100 | C+ | 77–79.99 |
| A | 93–96.99 | C | 73–76.99 |
| A− | 90–92.99 | C− | 70–72.99 |
| B+ | 87–89.99 | D+ | 67–69.99 |
| B | 83–86.99 | D | 63–66.99 |
| B− | 80–82.99 | D− | 60–62.99 |
| F | below 60 | | |
If your school starts an A at 93 or a D at 70, open Change the grading scale and enter its cut-offs. The plus and minus bands move with them.
How this differs from a class grade
This page scores one test. To combine several tests, quizzes and homework with different weights, use the grade calculator. To find what you need on an upcoming exam, use the final grade calculator.
Limitations
- Questions worth different points: use Points mode, because counting wrong answers assumes every question is worth the same.
- Rounding: some teachers round 89.5% up to 90%, and others don't. Pick the rounding that matches your class.
- Curves, drops and extra credit change the final grade. A score over 100% is shown, but the letter tops out at A+.
How we checked this
Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:
- 20 questions, 3 wrong: 85%, a B ✓
- 60 questions, 47 right: 78.33%, a C+ ✓
- 43.5 of 50 points: 87%, a B+ ✓
- 48 questions, 5 wrong: 89.58% is a B+, or an A− when rounded to 90% ✓
- Grading table for 7 questions: 1 wrong is 85.71% ✓
- Custom scale (A 93, B 85, C 77, D 70): 91% is a B+ ✓
- More wrong than questions is caught ✓
Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.
Questions people ask
How do I calculate a test score?
Subtract the number wrong from the number of questions, divide by the number of questions, and multiply by 100. 18 right out of 20 is 18 ÷ 20 × 100 = 90%.
What grade is 17 out of 20?
85%, which is a B on the usual scale (83–86.99%). Each question on a 20-question test is worth 5%.
How many can I miss and still get an A?
Look at the grading chart for your test length. On a 20-question test you can miss 2 (90%). On a 25-question test you can also miss 2 (92%), but 3 wrong is 88%, a B+.
Is 89.5% an A?
Only if your teacher rounds to the nearest whole percent. Without rounding, 89.5% is a B+. Use the Rounding option to see both.
What is an EZ-grader?
A slide chart teachers use to read off the percent for each number wrong. The grading chart under the result does the same for any test length.