Weighted Average Calculator
Enter each value with its weight on its own line. The weights decide how much each value counts towards the final average.
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The formula
Weighted average = (v1 x w1 + v2 x w2 + ...) / (w1 + w2 + ...)
How a weighted average works
A normal average treats every number equally. A weighted average lets some numbers count for more. You multiply each value by its weight, add those products together, and divide by the total weight.
The weights do not have to add up to 100. They can be percentages, credit hours, quantities or anything else, because dividing by the total weight takes care of the scaling.
A worked example
You scored 90 on the exam (worth 50%), 80 on the project (30%) and 70 on homework (20%). Weighted total: 90 x 50 + 80 x 30 + 70 x 20 = 4,500 + 2,400 + 1,400 = 8,300. Divide by the total weight, 100, and your weighted average is 83.
A simple average of the same three scores would have been 80, so the weighting helped you here because the best score counted most.
Other uses
- Average price paid when you bought shares in several batches
- Survey scores where some groups are larger than others
- Costing, when ingredients or materials have different quantities
Examples to check
Type these into the calculator above to see how it behaves. Every result below was produced by the same calculator code that runs on this page.
| What you enter | What you get |
|---|---|
| Values and weights (one pair per line: value weight): 90 50, 80 30, 70 20 | Weighted average: 83 |
| Values and weights (one pair per line: value weight): 85 40, 92 35, 78 25 | Weighted average: 85.7 |
| Values and weights (one pair per line: value weight): 100 1, 60 3 | Weighted average: 70 |
Weighted Average Calculator: frequently asked questions
Do my weights have to total 100?
No. The calculator divides by whatever the weights add up to, so 5, 3 and 2 work just as well as 50, 30 and 20.
Can a weight be zero?
Yes, that value is then ignored. But at least one weight must be above zero or there is nothing to average.
Do I have to separate numbers with commas?
No. Commas, spaces and new lines all work, so you can paste a column straight from a spreadsheet.
How accurate is this calculator?
It uses standard double-precision arithmetic, accurate to about 15 significant digits. Results are rounded only for display.
Is what I enter in this calculator saved or sent anywhere?
No. The calculation runs in your browser, so what you enter is not sent to our servers. We only count, anonymously, whether a tool ran successfully.
Is this calculator free to use?
Yes. It is free, needs no sign-up and has no usage limit.
Last reviewed: October 3, 2026