What is a grade calculator?
A grade calculator works out your overall course grade when different pieces of work count for different amounts, for example homework at 20%, a midterm at 30% and a final exam at 50%. It's a weighted average: each score counts in proportion to its weight. This one takes up to six components and also gives the letter grade.
The formula
Final grade = sum of (score × weight) ÷ sum of weights
Scores are percentages from 0 to 100. Weights are usually percentages too, but because the calculator divides by the sum of the weights, any consistent numbers work. Weights of 1, 1 and 2 give the same answer as 25, 25 and 50.
Worked example
| Component | Score | Weight | Score × weight |
|---|---|---|---|
| Quizzes | 88 | 20 | 1,760 |
| Midterm | 75 | 30 | 2,250 |
| Final exam | 92 | 50 | 4,600 |
| Total | 100 | 8,610 |
Final grade = 8,610 ÷ 100 = 86.1%, a B.
A plain average of the three scores would be 85.0%. The weighted grade is higher because the strongest score, the final, carries half the course.
Your grade so far
Leave out components you haven't done yet. With only the quizzes and the midterm entered:
(88 × 20 + 75 × 30) ÷ (20 + 30) = 4,010 ÷ 50 = 80.2%
That's your current grade on the 50% of the course already graded, not your final grade.
Letter grade scale
| Final grade | Letter |
|---|---|
| 90 and above | A |
| 80 to 89.9 | B |
| 70 to 79.9 | C |
| 60 to 69.9 | D |
| Below 60 | F |
This is a widely used US scale. Many schools add plus and minus grades or set different boundaries, so your syllabus is the final word.
How to use the calculator
- Find the grading breakdown in your course syllabus.
- For each component, enter your score as a percentage and its weight.
- Leave the weight blank for any slot you don't need, and it's skipped.
- Read the final grade, rounded to one decimal place, and the letter grade.
If a category such as homework has many assignments, average them first and enter the category as one line with its total weight.
Working out what you need on the final
The calculator doesn't solve backwards, but the arithmetic is short. If your current grade is G on the work done so far, and the final exam is worth w of the course (as a decimal), the score you need for a target T is:
Needed = (T − G × (1 − w)) ÷ w
From the example above, a current 80.2% with a final worth 0.5:
- For a B (80%): (80 − 40.1) ÷ 0.5 = 79.8%
- For an A (90%): (90 − 40.1) ÷ 0.5 = 99.8%
If the answer is above 100, the target isn't reachable through the final alone.
Limits
- Six components. Combine smaller items into categories if you have more.
- Dropped scores and extra credit aren't modeled. Apply your course's rules to the scores before entering them.
- Points-based courses. If your course totals raw points instead of weighting categories, divide total points earned by total points possible instead.
- Rounding. Some instructors round 89.5 up to 90. The calculator doesn't, so 89.96 shows as 90.0% but is graded as a B.
Related calculators
- GPA calculator: turn letter grades from all your courses into a GPA.
- Percentage calculator: convert points to percentages.
- CGPA to percentage calculator: for 10-point grading systems.
- Study time calculator: plan revision time before the final.
Last updated