Weighted Average Calculator
Average a set of values where some count more than others — add as many value-and-weight pairs as you need and see both averages.
How to use it
- Enter each value with the weight that goes with it.
- Weights do not need to add up to 100 — they are normalised for you.
- The plain average is shown alongside so you can see the difference weighting makes.
Examples
| 90×3, 76×2, 84×5 | 84.2 |
| Equal weights | Same as the plain mean |
A weighted average gives each value influence in proportion to its weight, rather than treating every entry the same. It answers a different question than a plain mean: not 'what's typical across these items' but 'what's the overall result once size, importance or credits are accounted for'.
Worked example — course grade with credit weighting
A student scores 90 in a 3-credit course, 76 in a 2-credit course and 84 in a 5-credit course. The plain average of 90, 76, 84 is 83.3 — but the weighted average, (90×3 + 76×2 + 84×5) ÷ (3+2+5) = 842 ÷ 10 = 84.2, reflects that the 5-credit course counts for half the total workload. That's the number that actually matches a GPA calculation.
Where this differs from a plain mean
- Portfolio returns — a large holding should move the average more than a small one.
- Survey results — combining groups of different sample sizes.
- Course grades — credit hours, not course count, should drive the GPA.
- Manufacturing quality — a batch of 10,000 units shouldn't count the same as a batch of 10.
Questions people ask
When should I use a weighted average instead of a plain one?
Whenever the items are not equally important — course credits, portfolio holdings, survey samples of different sizes. A plain mean silently treats them all the same.
Is anything sent to a server?
No. Every calculation runs in your browser, so nothing you type is uploaded and the page keeps working offline once it has loaded.
Also searched for
People find this page looking for weighted average formula.
Last updated 17 August 2026