Weighted Average: What It Is, How to Calculate It, and How It Differs from a Simple Average
A weighted average is an average in which every grade has a weight, so a grade with a large weight moves the result more than one with a small weight. To calculate it, multiply each grade by its weight, add up the products, and divide by the total of the weights. That is how a degree average is calculated from credits, and how a final course grade is calculated from percentages.
The formula
The weight can be anything that expresses importance. Across a degree it is the number of credits a course carries. Inside a course it is the percentage of each component, such as the exam and the assignments. On a 4.0 scale it works the same way: multiply each course's grade points by its credit hours.
Example 1: a degree average by credits
| Course | Grade | Credits | Grade × credits |
|---|---|---|---|
| Calculus 1 | 88 | 5 | 440 |
| Intro to Economics | 92 | 4 | 368 |
| Statistics | 79 | 3.5 | 276.5 |
| Total | 12.5 | 1,084.5 |
The weighted average is 86.76. A simple average of the three grades would be 86.33, because it treats the 3.5-credit Statistics course as if it counted as much as the 5-credit Calculus course. The gap is small here, but it grows as the difference between heavy and light courses grows.
Example 2: a final course grade by percentages
| Component | Grade | Weight | Grade × weight |
|---|---|---|---|
| Final exam | 84 | 70% | 58.8 |
| Assignments | 95 | 30% | 28.5 |
| Total | 100% | 87.3 |
When the weights are percentages that add up to 100, you only need to add up the last column: the final grade is 87.3. A simple average of 84 and 95 would be 89.5, because it gives the assignments the same weight as the exam.
Weighted average vs simple average
| Simple average | Weighted average | |
|---|---|---|
| How to calculate | Sum of grades divided by how many there are | Sum of (grade × weight) divided by the sum of the weights |
| Weight of each grade | Equal for all | By credits, percentages or units |
| When they match | Only when every grade has the same weight | |
| Where it is used | Mostly quick mental math | Degree average, final course grade, GPA |
The rule worth remembering: a weighted average is pulled toward the grades with the largest weights. A low grade in a 6-credit course drags the average down much more than the same grade in a 2-credit course. So when you decide which course gets more of your time, look at the credits too.
How to calculate a weighted average in Excel or Google Sheets
Put the grades in one column and the weights in the column next to it. With the grades in B2 to B4 and the weights in C2 to C4, the formula is:
SUMPRODUCT multiplies each grade by its weight and adds up the products, and SUM adds up the weights. The same formula works in Google Sheets. If you add a course, extend the range in both parts of the formula.
Three mistakes that change the result
- Dividing by the number of grades instead of the total weight. This is the most common one. In the first example you divide by 12.5 (the total credits), not by 3 (the number of courses).
- Percentages that don't add up to 100. If a component has no grade yet, for example an exam that hasn't happened, divide by the weights you already have. The result is your current grade, not your final one.
- Including courses without a numeric grade. A pass/fail or exempted course earns credits but usually doesn't count toward the average. Rules differ between institutions, so check yours if in doubt.
You don't have to do it by hand. Focusity has two free calculators that run in your browser, no sign-up: a GPA calculator by credits and a final grade calculator that also shows what you need on the exam to reach your target.
Calculate my averageFrequently asked questions
What is a weighted average?
An average in which every grade has a weight, so a grade with a larger weight moves the result more. Across a degree the weight is the number of credits a course carries, and inside a course it is the percentage of each component.
How do you calculate a weighted average?
Multiply each grade by its weight, add up the products, and divide by the total of the weights. For example, 88 in a 5-credit course, 92 in a 4-credit course and 79 in a 3.5-credit course give 1,084.5 divided by 12.5, which is 86.76.
What is the difference between a weighted average and a simple average?
A simple average gives every grade the same weight and divides by the number of grades. A weighted average gives more weight to the grades that matter more and divides by the total weight. The two are equal only when every grade has the same weight.
How do I calculate a weighted average in Excel?
Put the grades in one column and the weights in the next, then use =SUMPRODUCT(B2:B4,C2:C4)/SUM(C2:C4), with the grades in column B and the weights in column C. The same formula works in Google Sheets.
What if the percentages don't add up to 100?
Divide by the total of the percentages that already have a grade, instead of by 100. This usually happens when an exam hasn't taken place yet, and the result is your current grade in the course rather than the final one.
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