How to Calculate the Percentage of Correct Answers

What is the percent-correct formula?

Percent correct = (correct answers ÷ total questions) × 100. The division gives you a decimal between 0 and 1, the share of the test you answered correctly, and multiplying by 100 turns that decimal into a percentage. It works the same way for a 10-question quiz, a 50-question exam, or a 200-question final.

When you know your wrong answers instead, use the equivalent form: percent correct = (total − wrong) ÷ total × 100. Seven wrong on a 40-question test is (40 − 7) ÷ 40 × 100 = 82.5%. Both versions give the same answer, so use whichever number is written at the top of the test.

• Count the questions you answered correctly, or subtract your wrong answers from the total.
• Divide that number by the total number of questions.
• Multiply the result by 100 to get the percentage.
• Round only at the end, using your teacher's rounding rule if the score lands on a half.

Percentage of correct answers: worked examples

The table below runs the formula on common test sizes and shows the letter grade each result earns on the standard plus/minus scale. The last two columns are where students usually second-guess themselves. A 33 out of 40 feels like a B but is a B−, and a 45 out of 48 feels like an A− but is a full A.

For a full table of every possible score on one test length, open the page for that size, such as the grading scale for 25 questions. For any other fraction, what grade is X out of Y? covers odd totals.

What if questions are worth different points?

When questions carry different point values, your percentage of questions correct and your percentage of points earned are two different numbers, and your grade uses the points. The simple formula assumes every question counts the same. Once a test mixes 2-point and 6-point questions, you have to divide points earned by points possible instead.

Here's a 20-question test with 15 multiple-choice questions worth 2 points each (30 points) and 5 short-answer questions worth 6 points each (30 points), 60 points in all. A student gets 14 multiple-choice and 2 short-answer questions right. That's 16 of 20 questions, or 80%, but only 28 + 12 = 40 of 60 points, which is 66.7%. The grade is a D, not the B the question count suggests. The points grade calculator handles mixed-value tests.

How do you count partial credit and half points?

Count partial credit as the fraction of the question's points you earned, then use points earned in the formula. If a 20-point quiz gives half credit on one question, your score might be 17.5 out of 20, and 17.5 ÷ 20 × 100 = 87.5%. Most calculators accept decimals, so you don't have to round the partial point away.

The mistake to avoid is counting a half-credit question as fully right or fully wrong. On a 10-question quiz with 8 fully correct answers and one half-credit answer, the score is 8.5 ÷ 10 = 85%. Rounding it to 9 correct gives 90%, and rounding it to 8 gives 80%. Neither is the real score.

Do blank answers and guessing penalties change the percentage?

A blank answer counts as wrong on almost every classroom test, so it's included in the total and lowers your percentage just like a wrong one. Tests with a guessing penalty (also called negative marking) go further and subtract a fraction of a point for each wrong answer, while blanks score zero. There, raw score = correct − (penalty × wrong), and percent = raw score ÷ total × 100.

The SAT used this system, taking off a quarter point per wrong answer, until the redesigned test dropped the penalty in March 2016. On a 50-question test with that penalty, 40 right, 8 wrong, and 2 blank gives a raw score of 40 − (0.25 × 8) = 38, or 76%, compared with 80% without the penalty. Check whether your test uses a penalty before deciding whether to guess. Without one, a guess can't lower your score.

Is percent correct the same as a percentile?

No. Percent correct is how much of the test you got right. A percentile is how you scored compared with other test takers. Answering 80% of questions correctly means you got 80 of every 100 right. Scoring in the 80th percentile means you did better than 80% of the people who took the test, whatever your raw score.

The two can be far apart. On a very hard exam, 65% correct might land in the 90th percentile. On an easy one, 90% correct might only reach the 50th. Classroom grades almost always use percent correct, while standardized tests and some curved courses report percentiles. The how do grade curves work guide explains when your rank changes your grade.

How do you turn percent correct into a letter grade?

Match your percentage to your school's grading scale: on the 10-point scale, 90–100% is an A, 80–89% a B, 70–79% a C, 60–69% a D, and below 60% an F. Plus/minus scales split each band further, so 82.5% is a B− and 84% a plain B. Your syllabus lists the exact cutoffs your teacher uses.

If the percentage lands on a half, such as 89.5%, your teacher's rounding policy decides whether it becomes an A− or stays a B+. The grade percentage chart lists every whole percentage with its letter on three scales, is 89% a B? settles the borderline cases, and the grade calculator converts a raw score to a letter in one step.