How to use the test grade calculator
- Number of questions or points — the total possible on the test. If questions carry different weights, enter total points instead.
- Number wrong or number correct — choose whichever is quicker to count. Half points are allowed for partial credit.
- Grading scale — the plain 10-point A–F scale, or a plus/minus scale.
- Rounding — tick the box if your school rounds 89.5% up to 90% before giving the letter.
The grading chart below the result lists every possible number wrong for that test length with its percentage and letter, so you can mark a class set without retyping. Use your browser's Print command to keep a paper copy.
The formula
Percentage = correct ÷ total × 100, and correct = total − wrong. Each question is worth 100 ÷ total percent, so on a 25-question test every miss costs 4 points.
Worked example
A test has 40 questions and a student misses 7:
- Correct: 40 − 7 = 33
- Percentage: 33 ÷ 40 = 0.825, so 82.5%
- Letter: a B on the 10-point scale, a B− on the plus/minus scale
Each question is worth 2.5%, so the student was 3 questions away from an A (4 wrong is exactly 90%).
Grading scales
The 10-point scale is the most familiar in U.S. schools: A from 90%, B from 80%, C from 70%, D from 60%, F below 60%.
The plus/minus scale here follows the percent ranges in the College Board's GPA conversion chart: A+ 97–100, A 93–96, A− 90–92, B+ 87–89, B 83–86, B− 80–82, C+ 77–79, C 73–76, C− 70–72, D+ 67–69, D 65–66 and F below 65. The College Board notes that schools may use different cutoffs, so check your district's or syllabus's grading policy if it differs.
How many can you miss? Quick chart
The most questions a student can get wrong and still earn each letter on the 10-point scale:
| Questions | Each worth | A (90%) | B (80%) | C (70%) | D (60%) |
|---|---|---|---|---|---|
| 10 | 10% | 1 | 2 | 3 | 4 |
| 15 | 6.67% | 1 | 3 | 4 | 6 |
| 20 | 5% | 2 | 4 | 6 | 8 |
| 25 | 4% | 2 | 5 | 7 | 10 |
| 30 | 3.33% | 3 | 6 | 9 | 12 |
| 40 | 2.5% | 4 | 8 | 12 | 16 |
| 50 | 2% | 5 | 10 | 15 | 20 |
| 100 | 1% | 10 | 20 | 30 | 40 |
Tests with 10, 20, 50 or 100 questions divide evenly; with 15 or 25 questions some scores land between whole percentages, which is where the rounding setting matters.
Tips for teachers
- Weighted sections: if multiple choice is worth 1 point and essays 10, grade on total points rather than question count.
- Extra credit: the calculator caps the score at the total, so add any bonus percentage to the result yourself.
- Course grades: to see how one test moves a semester grade, use the final grade calculator; for grade point averages, the GPA calculator.
Frequently asked questions
How do I calculate a test score percentage?
Divide the number correct by the total number of questions and multiply by 100. 21 correct out of 25 is 21 ÷ 25 × 100 = 84%.
What grade is 7 wrong out of 40?
33 correct out of 40 is 82.5% — a B on the 10-point scale and a B− on the plus/minus scale.
Does 89.5% round up to an A?
It depends on the school. Many teachers round to the nearest whole percent, which makes 89.5% a 90% and an A; others require a full 90%. Tick the rounding box to match your policy.
Can I grade by points instead of questions?
Yes. Enter the total points possible and the points lost (or earned). Half points are accepted for partial credit.
How do I print the grading chart?
The chart opens automatically under the result. Use your browser’s Print command (Ctrl+P or Cmd+P) or copy the table into a spreadsheet.
Last updated: October 8, 2026