Use the free Test Score Percentage Calculator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
From Right Answers to a Percent
A test score percent answers a simple question: what fraction of the test did you get right, expressed out of 100? If you answered 17 of 20 questions correctly, the fraction is 17 ÷ 20 = 0.85, and as a percent that is 85 percent. The formula never changes: correct answers divided by total questions, times 100. It works for a 10-question quiz, a 100-question exam, and everything in between, because the percent always rescales the result to the same 0-to-100 range.
Percents are useful because they let you compare tests of different lengths. An 85 percent on a 20-question test and an 85 percent on a 50-question test mean the same proportion correct, even though the raw counts differ. Teachers use percents for exactly that reason, and grade boundaries are usually set in percents too. That is why this tool also shows a letter grade on the common A-F scale, so you can read your result the way many schools do.
How to Use This Calculator
Enter the number of correct answers and the total number of questions, then press Calculate percent. The tool shows the percent to two decimal places, the letter grade, the number wrong, and the formula with your numbers filled in. Seeing the formula matters, because it lets you check the answer by hand in seconds, and checking is how you catch typing mistakes.
The tool only accepts whole numbers with correct answers between zero and the total, and a total of at least one. If you enter more correct answers than there were questions, or a total of zero, it says so plainly instead of giving a nonsense percent above 100 or a division by zero. Those checks protect you from the most common input errors.
A Worked Example
Suppose a test has 40 questions and you got 34 right. The percent is 34 ÷ 40 × 100 = 85 percent, a B on the common scale, with 6 wrong. Try it in the tool and follow the formula line: 34 ÷ 40 × 100 = 85.00 percent. Now try a shorter test: 9 right out of 10 is 90 percent, an A, with 1 wrong. One question matters much more on a short test, which is why short tests feel harsher: each question on a 10-question test is worth 10 percent, while each question on a 100-question test is worth only 1 percent.
Another example shows why percents beat raw counts for comparison. A score of 45 out of 50 is 90 percent. A score of 88 out of 100 is 88 percent. The raw count of 88 looks bigger, but the percent shows the first result is actually stronger. Whenever you compare two tests, convert to percents first, and the comparison becomes honest.
What the Letter Grade Means
The letter scale used here is the common one: A for 90 percent and above, B for 80 to 89, C for 70 to 79, D for 60 to 69, and F below 60. Many schools and countries use different boundaries, and some use plus and minus grades, such as B+ for 87 to 89. Always check your own school’s scale before you treat the letter as official. The percent is universal; the letter is a local convention.
Also remember that a percent does not measure difficulty. An 85 percent on a hard exam may reflect stronger work than a 95 percent on an easy quiz. Teachers sometimes adjust for difficulty with curves or scaling, which change the reported grade without changing your raw percent. If your grade looks different from your percent, ask whether a curve was applied.
Common Mistakes
The most common mistake is dividing the wrong way round: total divided by correct, which gives a number above 100 and looks impressive but means nothing. Always put correct answers on top. Another mistake is forgetting unanswered questions: a blank answer is usually wrong, so it belongs in the total but not in the correct count. Counting only the questions you attempted flatters the result.
A subtler mistake is rounding too early. If you round 17 ÷ 20 to 0.9 before multiplying, you get 90 percent instead of 85. Keep full precision until the last step, which is what this tool does, and only round the final percent. Small rounding errors can cross a grade boundary, so the order of operations matters.
Try It Yourself
Take your last three test results, convert each to a percent, and compare them honestly. Then try a “what if”: how many more correct answers would you have needed to reach the next letter? That gap, in questions, is often smaller than it feels in percents, and seeing it as a count of questions makes the next test feel achievable. Every calculation runs in your browser, and nothing you type is sent anywhere.
Related tools
- Calculadora de Porcentaje de Examen (Spanish version)
- Final Exam Grade Calculator
- Attendance Percentage Calculator