Weighted grade calculator
Put one score and weight on each line, for example "82, 20". Add an optional target and the calculator tells you what the rest of the course needs to average.
How this calculator works
Courses rarely count every piece of work equally. A final exam might be worth 40 percent while a quiz is worth 5. To combine them fairly, multiply each score by its weight, add the results and divide by the total weight completed so far.
The more useful question is usually "what do I need on the final?". If you have finished 70 percent of the course and are on 81 percent, the remaining 30 percent must supply whatever is missing from your target. The calculator rearranges the formula for you and flags a target that is out of reach.
The formula behind it
- current grade = Σ(score × weight) ÷ Σ weight
- needed = (target × 100 - Σ(score × weight)) ÷ remaining weight
A worked example
Scores of 82 (20%), 74 (30%) and 91 (20%) give 5,680 weighted points over 70% completed, which is 81.14%. To finish on 80% overall, the remaining 30% needs (8000 - 5680) ÷ 30 = 77.33%.
Questions people ask
Do the weights have to add up to 100?
Not for the entries you have so far. The total must not exceed 100, and whatever is left is treated as the work still to come.
What if the needed score is over 100%?
Then the target is out of reach unless extra credit exists. Lower the target and see what is realistic.
Can I use points instead of percentages?
Convert each to a percentage first by dividing by the maximum and multiplying by 100, so 18 out of 24 is 75.
Does this match my school's system?
Most use exactly this method. Some drop the lowest score or round at the end, so check your syllabus for special rules.