To find the grade you need on your final, use: required final score = (target grade − current grade × (1 − final weight)) ÷ final weight.
To find the grade you need on your final, use: required final score = (target grade − current grade × (1 − final weight)) ÷ final weight. For example, if you have 85% in the class, the final is worth 20% and you want 90% overall, you need (90 − 85 × 0.8) ÷ 0.2 = 110%, which isn't possible, but 88% overall needs (88 − 68) ÷ 0.2 = 100%.
That formula looks fiddly, but it's just a weighted average solved backwards. Once you see how it works, you can check any class in under a minute and stop guessing how much the final really matters.
This guide explains the formula step by step, gives worked examples for common weightings, a lookup table, and what to do when your class uses points instead of percentages. If you'd rather not do the arithmetic, the grade calculator works out weighted averages and the final score you need.
In this guide:
Your overall grade is a weighted average of everything before the final and the final itself:
Overall = current grade × (1 − w) + final score × w
Here, w is the weight of the final as a decimal. A final worth 25% has w = 0.25. "Current grade" is your average on everything else, on the same 0 to 100 scale.
To find the final score you need, rearrange for the final score:
Required final = (target − current × (1 − w)) ÷ w
In words: work out how many points your coursework already locks in, subtract that from your target, and divide what's left by the weight of the final.
Everything should be in percentages, and the weights of all parts of the course should add up to 100%. If your syllabus lists weights such as homework 20%, quizzes 15%, midterm 25% and final 40%, then w = 0.40 and your current grade is your weighted average of the other 60%.
Suppose you have 78% going into the final, the final is worth 30%, and you want at least 80% overall.
So you need about 85% on the final to finish with an 80%.
Check it by plugging the answer back in: 78 × 0.70 + 84.7 × 0.30 = 54.6 + 25.4 = 80.0. It's always worth doing this check, because it catches mistakes like using 30 instead of 0.30.
You have 88%, the final is worth 25% and you want to keep at least 85%.
(85 − 88 × 0.75) ÷ 0.25 = (85 − 66) ÷ 0.25 = 76%. You can score quite a bit lower than your current average and still keep your grade.
You have 72%, the final is worth 40% and the class needs 70% to pass.
(70 − 72 × 0.60) ÷ 0.40 = (70 − 43.2) ÷ 0.40 = 67%.
You have 80%, the final is worth 20% and you want 90% overall.
(90 − 80 × 0.80) ÷ 0.20 = (90 − 64) ÷ 0.20 = 130%. That's not achievable unless there's extra credit, so 90% is out of reach. The highest overall grade possible is 80 × 0.80 + 100 × 0.20 = 84%.
You have 65%, the final is worth 50% and you want 70%.
(70 − 65 × 0.50) ÷ 0.50 = (70 − 32.5) ÷ 0.50 = 75%. Heavily weighted finals give you the most room to change your grade, in either direction.
Final score needed for a range of starting grades and final weights, with a target of 80% overall. Values over 100% mean the target isn't reachable without extra credit; values under 0% mean you've already secured it.
| Current grade | Final worth 15% | Final worth 20% | Final worth 25% | Final worth 30% | Final worth 40% |
|---|---|---|---|---|---|
| 70% | 137% | 120% | 110% | 103% | 95% |
| 75% | 108% | 100% | 95% | 92% | 88% |
| 78% | 91% | 88% | 86% | 85% | 83% |
| 80% | 80% | 80% | 80% | 80% | 80% |
| 82% | 69% | 72% | 74% | 75% | 77% |
| 85% | 52% | 60% | 65% | 68% | 73% |
| 90% | 23% | 40% | 50% | 57% | 65% |
Notice the pattern. If your current grade equals your target, you need exactly your target on the final, whatever its weight. Above your target, a lighter final protects you more; below it, a heavier final gives you a better chance to catch up.
Many US classes add up raw points instead of weighting categories. In that case you don't need weights at all; just count points.
Required final points = (target % × total course points) − points you already have
Example: a course has 500 points in total, of which the final is worth 100. You have earned 340 of the 400 points so far and want 85% overall.
Points systems are really weighted averages in disguise: the final's weight is its share of total points, here 100 ÷ 500 = 20%. Check your syllabus to see which system your teacher or professor uses, because the same scores can give different results under each.
If your gradebook doesn't show a running total, calculate it yourself from the categories you've completed. Multiply each category average by its weight, add them up, and divide by the total weight completed so far.
| Category | Weight | Your average | Weight × average |
|---|---|---|---|
| Homework | 20% | 88% | 17.6 |
| Quizzes | 15% | 95% | 14.25 |
| Midterm | 30% | 76% | 22.8 |
| Total so far | 65% | 54.65 |
Current grade = 54.65 ÷ 0.65 = 84.1%. The remaining 35% is the final. To finish on 80%, you'd need (80 − 54.65) ÷ 0.35 = 72.4% on it.
Notice the shortcut in that last step. When you already have "weight × average" totals, you can skip computing the current grade and simply divide the points still needed by the final's weight. A percentage calculator helps if you only have raw scores like 38 out of 45.
Once you know your likely percentage, you'll usually want the letter grade. Scales vary by school, so always check your syllabus, but a common US scale is:
| Letter | Typical percentage | GPA points (4.0 scale) |
|---|---|---|
| A | 90 to 100 | 4.0 |
| B | 80 to 89 | 3.0 |
| C | 70 to 79 | 2.0 |
| D | Mid to high 60s | 1.0 |
| F | Below that | 0.0 |
The College Board's guide on converting grades to a 4.0 GPA scale uses this kind of table, and points out that many schools use pluses and minuses or different cut-offs. Colleges may also recalculate GPAs using their own rules.
Thresholds matter. If you're at 79.4% and your school rounds to the nearest whole number, a slightly better final could move you from a C+ to a B−. Run the formula with the exact cut-off as your target.
The same maths applies in UK universities, where a module mark is often a weighted mix of coursework and an exam. If coursework is 40% and you scored 62, and you want a 70 for the module, you need (70 − 62 × 0.4) ÷ 0.6 = 75.3 in the exam.
Watch for two differences from US classes. First, UK marks above 70 are already a first-class standard, so a "required 85" may be very demanding. Second, some modules require you to pass each component separately, often with 40 as the minimum, regardless of the weighted average.
For how module marks roll up into a final degree, see our guide to working out your degree classification.
The gradebook trap is the big one. If your online portal shows 62% two weeks before the final, check whether it's treating the unsat final as 0. Divide by the weight completed so far to get your real standing.
The required score is most useful as a planning tool, not a source of stress:
Running the formula for two or three targets, such as an A, a B and a pass, gives you a clear picture in minutes.
Use required final = (target − current × (1 − w)) ÷ w, where w is the final's weight as a decimal. With 78% now, a final worth 30% and a target of 80%, you need (80 − 54.6) ÷ 0.3 = 84.7%.
Then the target grade is not reachable from the final alone unless your class offers extra credit. Work out the highest possible grade by assuming 100% on the final, and set your target at the next achievable boundary.
It depends on the weight. Your grade can move by up to the final's weight multiplied by the gap between your current grade and your final score. A 20% final taken 10 points below your average lowers your grade by 2 points.
Multiply your target percentage by the total course points, subtract the points you already have, and divide by the points the final is worth. That gives the percentage you need on the final.
Multiply each completed category average by its weight, add those together, then divide by the total weight completed. Do not include the final as a zero.
Sometimes. With 85% and a final worth 40%, reaching 90% overall needs (90 − 51) ÷ 0.4 = 97.5% on the final. With a lighter final, it may be impossible.
Yes. Treat coursework and exam weights the same way. For example, coursework worth 40% with a mark of 62 needs 75.3 in the exam to reach a module mark of 70. Check any separate pass requirements too.
A weighted grade gives each category a share of the final grade, such as homework 20% and exams 50%. You multiply each category's average by its weight and add the results together.
Last checked: 19 October 2026. Figures, settings and guidance can change, so confirm anything important with the sources linked above.
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