Test Grade Calculator

Enter your points earned, or just how many questions you got wrong, and this calculator returns your percentage and letter grade with the working shown. It also builds two tables for your test: how many questions you can miss and still hold each grade, and the score for every possible number wrong.

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How test grades are calculated

A test grade is the fraction of available points you captured, written as a percentage. Whether you know your points earned or only how many questions you missed, it is the same arithmetic from two directions, and the letter is read off a scale. This calculator does both, shows the working, and then builds two tables for your specific test: how many questions you can miss and still hold each grade, and the score for every possible number wrong.

The formula

Grade % = (points earned ÷ points possible) × 100  =  ((total - wrong) ÷ total) × 100

Points earned is your raw score and points possible is the test's maximum. In the second form, total is the number of questions and wrong is how many you missed, with every question weighted equally.

Worked example

Points mode: you scored 52.5 out of 60 points. (52.5 ÷ 60) × 100 = 87.50%, a B+ on the plus / minus scale.

Wrong-answers mode: you missed 8 of 40 questions. ((40 - 8) ÷ 40) × 100 = 80.00%, a B-.

On that 40-question test each answer is worth 2.50 points, and the room you have is countable: 2 wrong still holds an A, 8 wrong still holds a B-, and 10 is the most you can miss and still hold a C.

The table that answers the real question

Most people looking up a test grade are not really asking what they scored, because they can usually work that out. They are asking how much room they have. So the results include a table running the arithmetic the other way: for every letter on your scale, the largest number of questions you can get wrong and still hold it.

That number is always a whole number, which is what makes it useful. On a 40-question test you can miss 2 and keep an A, or 4 and keep an A-, or 8 and keep a B-. Knowing that during a test tells you exactly how much slack you have on the questions you are unsure about, and knowing it afterwards tells you precisely how close a thing it was.

The per-question shortcut

Each question on an equally weighted test is worth 100 ÷ N points. On a 25-question quiz that is 4 points each, so every miss costs a predictable 4%, and three wrong is an 88%. On a 20-question quiz it is 5 points each, and on a 50-question test it is 2. This is worth knowing before a test rather than after, because it tells you what a single question is actually worth, and the answer is usually less than the anxiety attached to it.

Rounding is a policy, not maths

On a borderline score, no calculator can tell you what happens next, because it is not an arithmetic question. Some teachers round 89.5 up to the next letter, some truncate, and some round only the final course grade rather than individual tests. All three are legitimate and all three are decisions somebody made. If you are sitting on a number that is half a point from a boundary, your syllabus has the answer and this page does not. It is also a completely reasonable thing to ask about.

Which grading scale is yours?

Scales genuinely differ, so this calculator asks rather than picking one silently. Most colleges use a plus / minus scale where an A starts at 93. Most US high schools use a straight 10-point scale where an A starts at 90. Some schools use the traditional 7-point scale, where an A also starts at 93 but the passing line sits at 70 instead of 60. The same 91% is an A- on the first, a plain A on the second, and a B on the third, so the scale is worth thirty seconds to get right.

When a score comes out above 100

Usually extra credit, and usually good news. It is worth a quick check that your teacher counts it the way you are assuming, because some classes cap a test at 100 even when extra credit is on offer, and some let it run over. The calculator will happily compute a score above 100 and say so rather than silently trimming it, since quietly changing your number would be the less honest option.

Frequently asked questions

How do I calculate a test grade?

Divide the points you earned by the points possible, then multiply by 100. A 52.5 out of 60 is (52.5 / 60) x 100 = 87.50%. If you only know how many questions you missed, subtract them from the total first: 8 wrong out of 40 is ((40 - 8) / 40) x 100 = 80%.

How many questions can I get wrong and still get an A?

It depends on the length of the test and your scale, and the results work it out for you. On a 40-question test with an A starting at 93, you can miss 2. On a 25-question test you can miss 1. The table in your results gives that number for every letter grade, and it is always a whole number you can count.

What is each question worth?

On an equally weighted test, 100 divided by the number of questions. A 25-question quiz is 4 points per question, a 20-question quiz is 5, and a 50-question test is 2. Worth knowing before a test rather than after, because a single question is usually worth less than the worry attached to it.

What letter grade is an 87.5%?

On the plus / minus scale it is a B+, because that band runs from 87 to 89.99. On a straight 10-point scale it is a B, and on the 7-point scale it is also a B. Switch the scale selector to the one your class uses and the calculator will name the cutoff your score cleared.

Does my teacher round up?

That is a policy question rather than a maths one, and no calculator can answer it. Some teachers round 89.5 up to the next letter, some truncate, and some round only the final course grade rather than individual tests. All three are legitimate. If you are half a point from a boundary, your syllabus has the answer, and it is a perfectly reasonable thing to ask about.

What if my score is above 100%?

That usually means extra credit, and the calculator will compute it and say so rather than quietly trimming it back to 100. It is worth checking your teacher counts it the way you are assuming, because some classes cap a test at 100 even with extra credit on offer and some let it run over.

What if the questions are not all worth the same?

Then use the points mode rather than the questions mode. Add up the points you actually earned across the whole test and the points that were available, and enter those two totals. The questions-wrong mode assumes every question carries equal weight, which is what makes its grading chart possible.

Which grading scale should I pick?

The one your class uses. Most colleges use a plus / minus scale where an A starts at 93, most US high schools use a straight 10-point scale where an A starts at 90, and some use the traditional 7-point scale where the passing line is 70 rather than 60. The same 91% is an A- on the first, an A on the second and a B on the third.

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