Online Tool Store
Weighted Average Calculator
Calculate a weighted mean from editable values and weights with automatic normalization and a clear item-by-item formula breakdown in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Inputs
Values and weights
How it works
- Enter every value and its relative weight.
- Add or remove rows and optionally normalize weights to 100%.
- Read the live weighted result and item-by-item calculation breakdown.
Weighted average = Σ(value × weight) ÷ Σ(weights)
FAQ
What is a weighted average?
A weighted average gives some values more influence than others. Each value is multiplied by its weight, those products are added, and the total is divided by the sum of the weights.
Do weights have to total 100%?
No. The formula normalizes any positive total automatically, though percentages totaling 100% are often easiest to understand. Use Normalize weights if needed.
Can weights be decimals?
Yes. Values and weights can both be decimals, and weights must be zero or greater.
Are my numbers saved or uploaded?
No. The calculation runs locally with JavaScript and nothing is sent from your browser.
What happens if I enter a negative weight?
It's flagged as invalid - weights must be zero or greater, since a negative weight doesn't have a meaningful interpretation in a weighted average.
How we compare
| Feature | Online Tool Store | Spreadsheet | Basic calculator |
|---|---|---|---|
| Editable rows | ✓ | ✓ | Manual |
| Formula breakdown | ✓ | Formula only | No |
| One-click normalization | ✓ | Manual | No |