What this calculator does
Turn the number of questions you got right or wrong into a percent score and a letter grade. A test score is just a fraction: the questions you got right divided by the questions on the test. It's written as a percent. This calculator does that division for you, whether you know how many you got right or how many you missed. It shows the points you earned, too. Then it turns the percent into a letter grade, using cut-offs you can change.
It also builds a grading table for your test size. The table lists every possible number wrong, with its points, percent and letter. Teachers use a table like this to mark a stack of papers quickly. Students use it to see how many questions they can miss and still get the grade they want.
Where it's used
Why this math matters outside the classroom:
- Scoring a quiz. Answering 27 of 30 questions correctly is a score of 90%.
- Points lost. Missing 7 of 25 questions leaves 18 correct, which is 72%.
- Grading scales. Teachers turn a percentage into a letter grade using the cutoffs on their grading scale.
- Making answer keys. Teachers build a table of scores for each number correct before grading a stack of tests.
Grade level and standards: Grade 6; Common Core State Standards for Mathematics 6.RP.A.3.c. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Choose whether you're entering the number wrong or the number correct.
- Enter the total number of questions and the count you chose, plus the points each question is worth.
- If your class doesn't use 90, 80, 70 and 60, adjust the letter cut-offs.
- Read your score and letter. Then scroll the grading table to see every other possible result.
What the inputs mean
- Total questions
- Every question that counts toward the score, from 1 to 500. Don't include bonus questions.
- Points per question
- What each question is worth. It changes the points earned but not the percent, because every question is worth the same amount.
- Lowest percentage for an A
- The lowest percentage that still earns an A. Each cut-off must be lower than the one above it.
- Lowest percentage for a D
- Anything below the D cut-off is an F.
Formula and method
correct = total − wrong score % = correct ÷ total × 100 points earned = correct × points per question letter = the highest letter whose cut-off is at or below the score
In the formulas, "total" is the number of questions, and "wrong" and "correct" are how many you missed and got right. Every question counts the same. So the percent is the same whether you count questions or points. For example, 22 of 25 questions is 88%, and 88 of 100 points is also 88%. The points per question only changes how the raw total looks.
Each question is worth 100 ÷ total percentage points. So on a 25-question test, every miss costs 4%. On a 40-question test, it costs 2.5%. To find the letter, the calculator checks the cut-offs in order. At or above the A cut-off is an A. Otherwise, at or above the B cut-off is a B, and so on. Everything under the D cut-off is an F.
Behind the scenes, the calculator works out correct × 100 ÷ total instead of (correct ÷ total) × 100. That way, a score landing exactly on a cut-off isn't nudged below it by computer rounding. For example, 18 of 20 stays exactly 90%.
Worked example
A 25-question quiz is worth 4 points per question, and a student misses 3 questions. The class uses a 90/80/70/60 scale.
- Questions correct: 25 − 3 = 22.
- Points: 22 × 4 = 88 earned out of 25 × 4 = 100 possible.
- Score: 22 ÷ 25 × 100 = 88%.
- 88% is below 90 but at least 80, so the letter is a B.
Result: The student scores 88%, a B. Each missed question on this quiz costs 4 percentage points.
Understanding the result
Use the grading table to find the most questions you can miss for a given letter. Look for the last row that still shows that letter.
On short tests, each question swings the grade a lot. On a 10-question quiz, one miss drops the score by 10 points. That's a whole letter on a standard scale.
The 'Each question is worth' result tells you how much a single question moves your percent.
Assumptions and limitations
- Every question is worth the same number of points.
- There's no partial credit, and no penalty for wrong answers beyond losing that question's points.
- A score exactly on a cut-off earns that letter.
- If sections of a test have different point values, score each section separately, or use a weighted average.
- Plus and minus grades aren't shown. Schools that use them split each letter band further.
- Some teachers round scores, for example 89.5% up to 90%. This calculator doesn't round before assigning the letter.
Frequently asked questions
How many questions can I miss and still get an A?
Multiply the total by (100 − A cut-off) ÷ 100 and round down. On a 25-question test with a 90% cut-off, that's 25 × 0.10 = 2.5. So you can miss 2 and still have 92%. A third miss gives 88%. The grading table shows this for you.
Does the points value change my percentage?
No. When every question is worth the same, points earned ÷ points possible always equals questions correct ÷ total questions. The points value is there so the raw total matches what's written on the paper.
What if my teacher uses a different scale?
Change the four cut-offs. Some schools use 93, 85, 77 and 70, for example. The letter result and every row of the grading table update to match.
How do I handle a test with bonus questions?
Enter only the regular questions as the total, and score the bonus separately. Bonus points add to the points earned without adding to the points possible. That can push the score above 100%.
How this calculator is checked
Method: Definition of a percentage score (correct ÷ total × 100) and threshold-based letter grading. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
Embed this calculator
Put this Test Grade Calculator on your own website or blog for free. Paste this code where you want it to appear: