Grading a stack of quizzes or checking your own test score? This test grade calculator converts the number of questions you got wrong — or right — into a percentage and a letter grade instantly. It also builds a full grading chart showing the score for every possible number wrong, the same “easy grader” chart many teachers keep beside them while marking. The chart updates as soon as you change the total.
The letter grade uses the most common U.S. scale with plus and minus grades (A 93–96, A− 90–92 and so on). Schools set their own cutoffs, so check your syllabus. When the term ends, turn letter grades into a GPA with the high school gpa calculator or the weighted gpa calculator for honors and AP courses.
How to use the test grade calculator
- Enter the total number of questions, or the total points if questions carry different weights.
- Choose whether you will enter the number wrong (points lost) or the number right (points earned).
- Enter that number. The percentage, letter grade and chart appear instantly.
- Teachers: keep the total fixed and read each student's score straight off the chart.
Formula
Each question is worth 100 ÷ Total percentage points. On a 25-question test, every question is worth 4 points; on a 40-question test, 2.5 points. Scores are shown to two decimal places — round according to your school's policy.
Worked example
A 25-question quiz, and you got 3 wrong.
- Correct answers: 25 − 3 = 22.
- Score: 22 ÷ 25 × 100 = 88%.
- On the standard scale, 88% is a B+ (87–89).
With points instead: a test worth 80 points where the student lost 14 scores (80 − 14) ÷ 80 = 82.5%, a B.
Standard U.S. letter grade scale
| Letter | Percent | GPA points (4.0 scale) |
|---|---|---|
| A+ | 97–100 | 4.0 |
| A | 93–96 | 4.0 |
| A− | 90–92 | 3.7 |
| B+ | 87–89 | 3.3 |
| B | 83–86 | 3.0 |
| B− | 80–82 | 2.7 |
| C+ | 77–79 | 2.3 |
| C | 73–76 | 2.0 |
| C− | 70–72 | 1.7 |
| D+ | 67–69 | 1.3 |
| D | 63–66 | 1.0 |
| D− | 60–62 | 0.7 |
| F | Below 60 | 0.0 |
This is a widely used convention, not a universal standard. The College Board's BigFuture notes that some schools do not use pluses and minuses and others use different cutoffs.
Curving a test: three common methods
Teachers sometimes adjust scores when a test turned out harder than intended. Whatever method you use, apply it the same way to every student and tell them how it works.
- Add flat points. Add the same number of percentage points to every score, for example +5%. Simple and transparent, but it can push top scores over 100%.
- Scale to the top score. Divide each score by the highest score in the class and multiply by 100. If the best student scored 92%, a 78% becomes 78 ÷ 92 × 100 = 84.8%.
- Drop a question. If one question was flawed, remove it from the total for everyone. A 25-question test becomes 24 questions, and each remaining question is worth 4.17%.
To check the effect of dropping a question, just lower the total in the calculator above and re-read the chart.
Caveats and assumptions
- Grading scales vary by school, district and teacher; some use 90/80/70/60 without plus and minus, others use 94/87/80.
- If questions are worth different points, enter points rather than question counts.
- Partial credit works fine — enter decimals such as 2.5 points lost.
- Extra-credit questions that push a score above 100% are not modelled; add them to points earned manually.
Frequently asked questions
How do I calculate my test grade?
Subtract the number wrong from the total, divide by the total and multiply by 100. For example, 18 right out of 20 is 18 ÷ 20 × 100 = 90%.
What is 7 wrong out of 30?
23 right out of 30, which is 76.67% — a C on the standard plus/minus scale.
How much is each question worth?
Divide 100 by the number of questions. On a 20-question test each question is worth 5%; on a 50-question test, 2%.
What letter grade is 85%?
On the common plus/minus scale, 85% is a B (83–86). On a simple 90/80/70/60 scale it is also a B.
Can teachers use this as an easy grader?
Yes. Enter the total once and use the grading chart, which lists the percentage and letter grade for every number of wrong answers.
Sources
- College Board BigFuture — How to Convert Your GPA to a 4.0 Scale — letter grades, percent ranges and 4.0 scale
- NCES — High School Transcript Study (NAEP) — national data on high school grades and coursework
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.