How the Grade Calculator Works
A grade tells you how well you did in a test or in a whole course. The Grade Calculator turns points into a percentage and a letter, combines the parts of a course by their weights, and shows what you need on the final exam to reach a grade that you want.
Mode 1: one score
percentage = points earned / total possible points x 100
The percentage is rounded to 2 decimals, and the letter is taken from the rounded percentage. For example, 85 out of 100 is 85%, which is a B. A score of 89.996 out of 100 rounds to 90.00% and gets an A.
The calculator also shows the points you missed. If your score is higher than the total, which can happen with extra credit, the percentage goes above 100%.
The letter grades
| Percentage | Plain letter | With plus and minus |
|---|---|---|
| 97 to 100 | A | A+ |
| 93 to 96.99 | A | A |
| 90 to 92.99 | A | A- |
| 87 to 89.99 | B | B+ |
| 83 to 86.99 | B | B |
| 80 to 82.99 | B | B- |
| 77 to 79.99 | C | C+ |
| 73 to 76.99 | C | C |
| 70 to 72.99 | C | C- |
| 67 to 69.99 | D | D+ |
| 63 to 66.99 | D | D |
| 60 to 62.99 | D | D- |
| Below 60 | F | F |
Schools do not all use the same scale. Some have a different cutoff for an A or a D, and some do not use plus and minus. Check the scale of your school.
Chart: the grade scale
Each block is 2.5 percentage points. The calculator draws this scale with a marker at your grade.
0% 100% ████████████████████████████████████████ F (under 60) D 60-69 C 70-79 B 80-89 A 90-100
Mode 2: a weighted grade
In most courses, some parts count more than others. Each part has a score, a total and a weight. The calculator finds the percentage of each part, multiplies it by the weight, and adds the results:
weighted grade = sum of (percentage x weight) / sum of the weights
Example:
| Part | Percentage | Weight | Points of the grade |
|---|---|---|---|
| Homework | 92% | 30% | 92 x 0.3 = 27.6 |
| Midterm | 78% | 30% | 78 x 0.3 = 23.4 |
| Project | 88% | 40% | 88 x 0.4 = 35.2 |
| Total | 100% | 86.2% (B) |
Each block below is one point of the final grade, and the color shows the letter of that part.
Homework ████████████████████████████ 27.6 points Midterm ███████████████████████ 23.4 points Project ███████████████████████████████████ 35.2 points
If the weights do not add up to 100%, for example because the final exam is still to come, the calculator divides by the sum of the weights that you entered. The result is your grade for the work that is done so far.
Mode 3: what do I need on the final?
needed = (wanted grade - current grade x (1 - weight)) / weight
The weight is the share of the final in the course grade, written as a decimal (30% = 0.30). Example: your grade is 88%, the final is worth 30%, and you want to end with 85%. Needed = (85 - 88 x 0.70) / 0.30 = (85 - 61.6) / 0.30 = 78%.
The table shows what you need for a current grade of 88% and different weights of the final:
| Weight of the final | To get 90% | To get 85% | To get 80% |
|---|---|---|---|
| 10% | 108.0% | 58.0% | 8.0% |
| 20% | 98.0% | 73.0% | 48.0% |
| 30% | 94.7% | 78.0% | 61.3% |
| 40% | 93.0% | 80.5% | 68.0% |
| 50% | 92.0% | 82.0% | 72.0% |
Chart: the score needed for an 85%
The more the final is worth, the closer the score you need is to the grade that you want. Each block is 2.5 points. Your current grade is 88%.
10% ███████████████████████ 58.0% 20% █████████████████████████████ 73.0% 30% ███████████████████████████████ 78.0% 40% ████████████████████████████████ 80.5% 50% █████████████████████████████████ 82.0%
If the answer is more than 100%, the grade is out of reach unless there is extra credit. If it is 0 or less, you already have the grade even with a zero on the final. The calculator also shows the worst case (0 on the final) and the best case (100%).
Tips
- Use the weights from your syllabus. They are often given as a percent for each type of work.
- Enter the parts you have finished. Leave the others out to see your grade so far.
- Check how your teacher rounds. Some round 89.5% up to 90%, and some do not.
- Some courses drop the lowest score. This calculator does not do it, so remove that part yourself.
What this calculator does not include
- Grade point averages (GPA), or a scale of 4.0.
- Dropping the lowest score, and points-based courses where every point counts the same. For the second, use mode 1 with the total points.
- The rules of your school, such as pass and fail cutoffs.
This tool gives an estimate for planning. Your teacher or school decides your final grade.