Weighted Average Calculator
Average values that contribute with different weights.
Result
Weighted average: 85
Weights are relative; multiplying every weight by the same amount does not change the average.
- Weighted sum
- 255
- Total weight
- 3
- Number of rows
- 2
https://calcgallery.com/everyday-math/weighted-average-calculator/
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How to use the Weighted Average Calculator
- Enter each value and its positive relative weight.
- Add rows for every distinct value or group.
- Check the weighted sum and total weight behind the average.
Contribution divided by total weight
Each value is multiplied by its weight. Those contributions are added and divided by the sum of the weights:
weighted average = Σ(value × weight) ÷ Σ(weight)Only relative weights matter. Scaling every weight by the same positive amount does not change the result. Do not average already-computed group averages without weighting them by the sizes of their groups.
With your numbers
- Weighted sum = 255; total weight = 3.
- Weighted average = weighted sum ÷ total weight = 85.
Quick reference
Weights are relative; multiplying every weight by the same amount does not change the average.
| Example | Weighted average |
|---|---|
| 80 twice and 95 once | 85 |
| Equal weights | 20 |
| Percentage-style weights | 81 |
| Decimal weights | 7 |
| One value | 42 |
| Negative values | 5 |
Common questions about the Weighted Average Calculator
- What does a weight mean?
- It states how strongly a value contributes relative to the others. It can be a count, percentage share or another positive importance measure.
- Do weights need to add to 100?
- No. The formula divides by their total, so weights of 2 and 1 give the same average as 20 and 10.
- Can a weight be zero?
- This calculator requires positive weights. Remove a row instead of including a value that contributes nothing.
- Is a weighted average the same as an ordinary mean?
- Only when every value has the same weight.