How to use the test score calculator
- Enter the points earned in the first field.
- Enter the total points possible for the test or assignment.
- Select a grading scale: Standard uses whole letters, while Plus/Minus adds pluses and minuses.
- Read the calculated percentage, letter grade, and points missed below.
How the test score percentage is calculated
The formula used by this test score calculator is straightforward: divide the points earned by the total points possible, then multiply by 100.
Percentage = (Earned / Total) x 100
For example, if you scored 42 out of 50 points: (42 / 50) x 100 = 84%. The result is rounded to remove floating point noise so that exact fractions like 1/3 display cleanly as 33.333... rather than long repeating decimals with rounding errors.
Standard grading scale reference
The Standard scale assigns whole letter grades based on ten point bands. This is the most common system in US high schools and many colleges.
| Percentage range | Letter grade |
|---|---|
| 90 to 100 | A |
| 80 to 89.99 | B |
| 70 to 79.99 | C |
| 60 to 69.99 | D |
| Below 60 | F |
If your school uses a different threshold, such as an A starting at 93 percent, select the Plus/Minus scale instead.
Plus and minus grading scale
The Plus/Minus scale breaks each ten point band into three parts. It gives more granular feedback and is widely used in universities.
| Percentage range | Letter grade |
|---|---|
| 97 to 100 | A+ |
| 93 to 96.99 | A |
| 90 to 92.99 | A- |
| 87 to 89.99 | B+ |
| 83 to 86.99 | B |
| 80 to 82.99 | B- |
| 77 to 79.99 | C+ |
| 73 to 76.99 | C |
| 70 to 72.99 | C- |
| 67 to 69.99 | D+ |
| 63 to 66.99 | D |
| 60 to 62.99 | D- |
| Below 60 | F |
Handling partial credit and decimal scores
Not every test uses whole numbers. If a teacher awards half points or partial credit, you can enter decimals directly. For instance, earning 33.5 out of 40 points gives (33.5 / 40) x 100 = 83.75%, which maps to a B on the standard scale.
This exam grade calculator accepts any non negative number, including values with several decimal places. Just make sure the points earned does not exceed the total points possible unless your instructor allows extra credit.
Common mistakes when calculating grades
A frequent error is dividing the total points by the earned points instead of the other way around. Always put the smaller earned number on top: Earned / Total.
Another mistake is mixing up the grading scale. An 89 percent is a B under the standard scale but a B+ under some plus/minus systems. Always check which scale your syllabus specifies before assuming your letter grade.
Finally, remember that weighted categories change things. If a test is worth 30 percent of your final grade, you need a weighted average across all categories. You can use the percentage calculator to work out weighted contributions.
Worked examples
Each result below was produced by the same code the tool runs, so you can check your own numbers against them.
| Example | Input | Result |
|---|---|---|
| Typical quiz | Points earned: 17; Total points possible: 20; Grading scale: standard | Percentage: 85%; Letter grade: B; Points missed: 3 |
| Final exam | Points earned: 82; Total points possible: 100; Grading scale: plussminus | Percentage: 82%; Letter grade: B-; Points missed: 18 |
| Partial credit | Points earned: 33.5; Total points possible: 40; Grading scale: standard | Percentage: 83.75%; Letter grade: B; Points missed: 6.5 |
| Perfect score | Points earned: 50; Total points possible: 50; Grading scale: standard | Percentage: 100%; Letter grade: A; Points missed: 0 |
FAQ
How do I calculate my test score as a percentage?
Divide the points you earned by the total points possible, then multiply by 100. For example, 42 out of 50 is (42 / 50) x 100 = 84 percent.
What letter grade is an 85 percent?
On the standard scale, 85 percent is a B. On the plus/minus scale, it is also a B because it falls between 83 and 86.99.
Can I use this test score calculator for extra credit?
Yes. If your earned points exceed the total possible points, the calculator will show a percentage above 100. Check whether your school caps grades at 100 percent.
Is my data sent to a server?
No. All calculations happen locally in your browser. Nothing you type is uploaded or stored.
What is the difference between the two grading scales?
The Standard scale uses five whole letter grades (A through F). The Plus/Minus scale adds modifiers like A- and B+, creating thirteen distinct grade levels for more precise scoring.
How many questions can I miss to get an A?
It depends on the total number of questions. On a 50 question test where each question is worth one point, you need at least 45 correct for a 90 percent (an A on the standard scale), meaning you can miss up to 5.