Grade Calculator

Grade calculator at a glance#

How do you calculate a weighted grade?#

Multiply each score by its weight, add the results, then divide by the total weight. Homework at 90 worth 20%, quizzes at 84 worth 15% and a midterm at 78 worth 25% give (18 + 12.6 + 19.5) ÷ 0.60 = 83.5%. Type each score and weight into the Average grade tab above and you get the weighted grade, its letter and the total weight you've entered.

What grade do I need on my final?#

Subtract the points you've already locked in from the grade you want, then divide by the final's weight. With 83.5% going into a final worth 40%, a course grade of 85% needs (85 − 83.5 × 0.6) ÷ 0.4 = 87.25% on the final. The Final grade tab does this from three numbers: your current grade, the grade you want and what the final is worth.

How do I calculate my grade with points?#

Add up the points you've earned and divide by the points possible. 412 points out of 480 is 412 ÷ 480 = 0.8583, or 85.83%. That only works when your teacher grades on total points. If the syllabus lists categories with percentages, use the weighted method instead.

Why a weighted grade isn't a plain average#

Most syllabi split the course into categories and give each one a share of the grade. A final exam worth 40% counts eight times as much as a homework set worth 5%, so you can't just average your scores. Each category's score has to be scaled by its weight first.

Here's the class used on this page. The syllabus says homework is 20%, quizzes 15%, the midterm 25% and the final exam 40%. You've finished everything except the final, with 90 on homework, 84 on quizzes and 78 on the midterm.

1. Turn each weight into a decimal: 0.20, 0.15 and 0.25.
2. Multiply each score by its weight: 90 × 0.20 = 18, 84 × 0.15 = 12.6 and 78 × 0.25 = 19.5.
3. Add the products: 18 + 12.6 + 19.5 = 50.1. These are the course points you've earned so far.
4. Divide by the weight that's been graded: 50.1 ÷ 0.60 = 83.5%.

That last step is the one people skip. The three categories only cover 60% of the course, so 50.1 points out of a possible 60 is your current grade, 83.5%. Dividing by 1 instead would make it look like you're failing at 50.1%. The calculator handles this for you because it always divides by the weights you've entered, so they don't need to add up to 100. It only stops you if they go over 100.

A plain average of 90, 84 and 78 would be 84, half a point higher than the real grade, because the midterm you scored lowest on carries the most weight of the three.

The same method shows up in instructors' own grading guides. A handout from a Troy University instructor walks through it category by category: work out a separate grade for each category, multiply it by the category's weight and add the results.

Categories with several assignments#

Most categories hold more than one score. Average the category first, then weight it. Four quizzes of 80, 88, 84 and 84 average 336 ÷ 4 = 84, which is the 84 used above. The average calculator does that step for any list of scores.

You can also enter each quiz as its own row and split the category's weight between them, 3.75% each for four quizzes in a 15% category. Both ways give the same course grade, and both are right only when every quiz is worth the same number of points. If they aren't, add the quiz points and divide by the points possible to get the category score.

What you need on the final exam#

The final-grade formula is the weighted grade run backward. Call the final's weight w, written as a decimal.

Score needed on the final = (target grade − current grade × (1 − w)) ÷ w.

For a target of 85% with a current grade of 83.5% and a final worth 40%:

1. The work you've done counts for 1 − 0.4 = 0.6 of the course, so it contributes 83.5 × 0.6 = 50.1 points.
2. You need 85 − 50.1 = 34.9 more points from the final.
3. The final is worth 40 points of the course, so you need 34.9 ÷ 0.4 = 87.25% on it.

Check it with the Average grade tab: add a fourth row for the final at 87.25 with a weight of 40 and the course grade comes out at exactly 85.

Every point on a 40% final moves your course grade by 0.4 points. Scoring 10 points higher on the final lifts the course grade by 4.

The calculator also tells you when a target is out of reach. Aiming for 93% from 83.5% would take 107.25% on a 40% final, so it reports the target isn't possible even with an A+. At the other end, if you'd keep your target even with an F on the final, it says so too.

Letter grades in the calculator#

Both tabs accept letter grades as well as percentages. When any row holds a letter, the calculator turns every score into a letter and then into grade points. Those run from 4.3 for an A+ and 4.0 for an A down to 0.7 for a D- and 0 for an F. Stanford gives an A+ the same 4.3. The calculator averages the grade points by weight and reports a letter.

That's what you see in the calculator's starting example. Homework of 90 is an A- worth 3.7, the project's B is worth 3.0 and a midterm of 88 is a B+ worth 3.3. Weighted by 5%, 20% and 20%, that's (3.7 × 5 + 3.0 × 20 + 3.3 × 20) ÷ 45 = 144.5 ÷ 45 = 3.21, which the calculator labels a B.

With numbers only, it reports the weighted percentage and finds the letter from the scale below, rounding to the nearest whole percent first, so 89.5% shows as an A-. Your school may draw the lines differently, so check the syllabus. To turn letter grades from several courses into one number, use the GPA calculator.

Score needed on the final, by weight#

The table runs the formula for a current grade of 83.5%. Each cell is the final exam score you need for the course grade in the left column. A heavier final makes a target above your current grade easier to reach, and a target below it harder to hold on to.

Sources#

• Troy University, How to Calculate Your Grade (instructor handout on weighted categories)
• Stanford Student Services, How Do I Calculate My Grade Point Average (GPA)? (letter grade points)

Frequently asked questions#

How do I calculate my grade if the weights don't add up to 100?#

Divide by the weights you have so far instead of by 100. Scores worth 60% of the course that earn 50.1 weighted points give 50.1 ÷ 0.60 = 83.5%. The calculator always divides by the total weight you enter, so you can use it partway through a term.

What do I need on my final to get an A?#

It depends on your current grade, the final's weight and where your class draws the line for an A. With 83.5% and a 40% final, finishing at 90% takes a 99.75% on the final. Finishing at 93% isn't possible, since it would take 107.25%.

How much is my final exam worth to my grade?#

Multiply the change in your final exam score by the final's weight. On a 40% final, every point you gain or lose moves your course grade by 0.4 points. On a 20% final it moves it by 0.2.

Can I enter letter grades instead of percentages?#

Yes. Type a letter such as B+ in the grade box. Once a letter is in the list, the calculator works in grade points, with an A at 4.0 and an A+ at 4.3, and returns a letter grade with its point average.

How do I find my test grade as a percentage?#

Divide the points you scored by the points possible and multiply by 100. 45 out of 50 is 45 ÷ 50 × 100 = 90%. The percentage calculator does the same for any pair of numbers.

Why is my weighted grade lower than my average?#

Your lowest scores are probably in the categories with the biggest weights. In the example on this page the midterm, the lowest score at 78, carries 25%, so the weighted grade is 83.5% while the plain average of the three scores is 84.