Weighted average calculator
An average that accounts for the credits or weight of each subject.
Calculator inputs
Results
Enter your values and press “Calculate” to see the result.
In short
- What it calculates
- An average that accounts for the credits or weight of each subject.
- Formula used
Weighted average = Σ (grade × weight) / Σ weights- Example
- Grades 8, 7, 9 and 6 with credits 6, 3, 9 and 4.5:
Weighted average calculator
When subjects carry different credit values, a simple average misleads: a 3-credit elective should not weigh the same as a 9-credit core module.
This calculator applies the right weight to every grade.
How it works
Each grade is multiplied by its weight, the products are added, and the total is divided by the sum of the weights.
The simple average is also shown so you can see the difference.
Formula
Weighted average = Σ (grade × weight) / Σ weights
Simple average = Σ grades / n
Worked example
Grades 8, 7, 9 and 6 with credits 6, 3, 9 and 4.5:
Products: 48 + 21 + 81 + 27 = 177
Sum of credits: 22.5
Weighted average: 177 / 22.5 = 7.87
The simple average would be 7.5.
Explanation
Where it appears outside the classroom
The weighted mean is not just for academic records. The consumer price index weights each spending category by its share of the household basket. An investment portfolio calculates its return by weighting each asset by the capital invested. An average purchase price weights each batch by the units acquired.
The mistake of averaging averages
If a shop sells at a 20% margin in January and 30% in February, the average margin for the two months is not 25% unless it sold exactly the same amount in both. Averaging percentages without accounting for the volume behind each is one of the most widespread errors in management reporting.
Weights do not have to add up to a hundred
They can be credits, hours, units sold or euros invested. The formula divides by the sum of the weights, so the result is correct whatever the total. Converting them to percentages is optional and only makes them easier to read.
When a weight is zero
An item with zero weight takes no part in the result, however high its score. It is the usual way to exclude an exempted subject or a period without activity, without having to delete the row.
Frequently asked questions
Can I use percentages as weights?
Yes. If an exam is worth 60% and coursework 40%, enter 60 and 40 as the weights.
Do the weights have to add up to 100?
No. The formula divides by the actual sum, so credits, hours or percentages all work.
Can I average percentages directly?
Only if they all represent the same volume. Otherwise each percentage must be weighted by the quantity behind it, or the result will mislead.
What happens if a weight is zero?
That item drops out of the calculation without affecting the result. It is how you exclude a row without deleting it.
Need to calculate something else?
These tools are often used alongside this calculator.
Grade average
Mean, median and pass count from your list of marks.
Grade needed
The minimum mark you need to reach your target for the course.
Average
Paste your list of numbers and get the mean, median, mode, range and standard deviation.