A weighted grade multiplies each score by its weight, adds the results, and divides by the total weight: scores of 90, 80 and 70 weighted 30%, 40% and 30% give (27 + 32 + 21) ÷ 100 = 80%. To find what you need on the final, subtract the points already earned from your target and divide by the weight of the final.
Most courses do not average your assignments equally — a final exam worth 40% moves your grade four times as much as a quiz worth 10%. Enter each piece of work with the weight it carries and this calculator returns your true course grade, then works out what you need on whatever is left. Each weighted score is a percentage-of-a-number problem; the percentage calculator covers the general case if you want to check one by hand.
Grade Calculator
Checked against: Scores of 90, 80 and 70 weighted 30%, 40% and 30% = 80.00% Last reviewed:
- Weight entered
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- Needed on the rest
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Sources and method
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How a weighted grade works
Each assignment contributes points equal to its score multiplied by its weight. Your grade is the total points earned divided by the total weight:
Grade = ∑(score × weight) ÷ ∑(weight)
The useful way to think about it is that every assignment carries a pot of points equal to its weight. A final worth 40% is a 40-point pot; scoring 75% on it collects 30 of those points. Your grade is the fraction of all available points you have collected.
A worked example
A course with three components:
- Homework, worth 30%, scored 90% → 0.90 × 30 = 27 points
- Midterm, worth 40%, scored 80% → 0.80 × 40 = 32 points
- Final, worth 30%, scored 70% → 0.70 × 30 = 21 points
Total earned is 27 + 32 + 21 = 80 points out of 100, so the course grade is 80%.
Note how different that is from a plain average of the three scores — which is also 80% here only by coincidence. Change the midterm score to 60% and the weighted grade drops to 72% while the simple average drops to 73.3%. The more uneven the weights, the further apart the two methods drift.
Working out what you need on the final
This is the question most people actually arrive with, and it is straightforward arithmetic:
Needed = (Target − Points already earned) ÷ Weight remaining × 100
Suppose you have completed:
- Homework, worth 20%, scored 95% → 19 points
- Midterm, worth 30%, scored 78% → 23.4 points
That is 42.4 points banked from 50% of the course, with a final worth the remaining 50%. To finish on 85%:
(85 − 42.4) ÷ 50 × 100 = 85.2% needed on the final
Aiming for 90% overall would require 95.2%. Settling for 70% overall needs only 55.2%. Running the same sum against a few different targets is the fastest way to work out where your revision time is actually worth spending.
Reading your syllabus correctly
Nearly every wrong answer comes from misreading the weighting scheme rather than from the arithmetic. Things to check before you start entering numbers:
- Category weights versus individual weights. “Homework: 20%” usually means all homework combined is worth 20%, not 20% each. Average the homework scores first, then enter that average against a weight of 20.
- Dropped scores. Many courses drop the lowest quiz or assignment. Omit it entirely and spread its weight across the rest of that category.
- Points-based courses. Some syllabi assign raw points rather than percentages — a 200-point final in a 1,000-point course is a weight of 20.
- Attendance and participation. Small in weight but frequently overlooked, and they can decide a borderline grade.
- Extra credit. Usually added as points on top rather than as a weighted component, so treat it separately.
Partly finished courses
You do not need the weights to total 100 for the calculator to be useful. Entering only the completed work shows how you are performing so far, which is the honest read mid-semester.
Just remember what that number means. A 92% across the first 40% of a course is a strong position, not a final grade — there is still 60% of the weight outstanding, and it can move things a long way in either direction.
Letter grade scales
Percentage-to-letter conversion is set by your institution, but a very common scale runs:
| Letter | Percentage | Grade points |
|---|---|---|
| A | 93–100% | 4.0 |
| A− | 90–92.9% | 3.7 |
| B+ | 87–89.9% | 3.3 |
| B | 83–86.9% | 3.0 |
| B− | 80–82.9% | 2.7 |
| C+ | 77–79.9% | 2.3 |
| C | 73–76.9% | 2.0 |
| C− | 70–72.9% | 1.7 |
| D+ | 67–69.9% | 1.3 |
| D | 63–66.9% | 1.0 |
| D− | 60–62.9% | 0.7 |
| F | below 60% | 0.0 |
Plenty of courses subdivide these with plus and minus bands, and some curve results against the cohort rather than against fixed thresholds. Check the syllabus rather than assuming, particularly if you are close to a boundary.
What you need on the final
A final exam worth 40% of the course is one of the most common set-ups, so here is the whole grid at a glance.
| Average so far (60% of course) | For a C (70%) | For a B (80%) | For an A (90%) |
|---|---|---|---|
| 55% | 92.5% | not reachable | not reachable |
| 60% | 85.0% | not reachable | not reachable |
| 65% | 77.5% | not reachable | not reachable |
| 70% | 70.0% | 95.0% | not reachable |
| 75% | 62.5% | 87.5% | not reachable |
| 80% | 55.0% | 80.0% | not reachable |
| 85% | 47.5% | 72.5% | 97.5% |
| 90% | 40.0% | 65.0% | 90.0% |
Common mistakes
- Averaging the scores and ignoring the weights. This is the whole point of weighting, and it is the error that produces the biggest surprises at the end of term.
- Entering a category weight for every item in it. Three homeworks at 20% each is 60% of the course, not 20%.
- Mixing points and percentages in the same column. Convert everything to percentages first.
- Forgetting the work you have not done yet. Your current grade only covers the weight you have entered.
- Trusting the number over the registrar. This is a planning tool; your institution’s system is the record that counts.
Frequently asked questions
How do I calculate a weighted grade?
Multiply each score by its weight, add those products together, then divide by the total weight entered. Scoring 90 on work worth 30%, 80 on work worth 40% and 70 on work worth 30% gives 27 + 32 + 21 = 80, divided by 100, which is 80%.
What grade do I need on the final exam?
Subtract the weighted points you have already earned from your target, then divide by the weight of the remaining work. If you have earned 42.4 points out of a possible 50 so far and the final is worth 50%, reaching 85% overall needs (85 – 42.4) / 50 x 100 = 85.2% on the final.
What is the difference between weighted and unweighted grades?
An unweighted average treats every assignment as equally important. A weighted average reflects what the syllabus actually says – a final worth 40% moves your grade four times as much as a quiz worth 10%. Almost all courses are weighted.
Do the weights have to add up to 100?
Not for this calculator. It divides by whatever weight you have entered, so a part-finished course still shows an accurate grade for the work completed. You only need the full 100% when you want to know your final standing.
Why does the calculator say my target is unreachable?
Because the score needed on the remaining work comes out above 100%. If your target requires more points than the outstanding assignments can possibly award, no result on them will get you there, and it is worth speaking to your instructor about the options.
How do I handle a dropped lowest grade?
Leave the dropped assignment out entirely rather than entering it with a weight of zero. Then redistribute its weight across the remaining assignments in that category, following whatever your syllabus specifies.
How do I convert a percentage to a letter grade?
It depends on your institution, but a very common scale is A at 90 and above, B at 80 to 89, C at 70 to 79, D at 60 to 69 and F below 60. Some courses use plus and minus bands or curve the results, so check your syllabus rather than assuming.
What if an assignment is marked out of points rather than as a percentage?
Convert it first: divide the points earned by the points available and multiply by 100. A score of 42 out of 50 is 84%. Enter that percentage along with the weight the assignment carries in the course.