Calculate a weighted mean from a list of values and a matching list of weights.
| Weighted mean | – |
Use this calculator when some numbers count more than others: exam grades with credits, a portfolio, or a mixture. The lists must be the same length. Separate entries with commas, semicolons, or spaces.
The calculation is: mean = Σ(value × weight) / Σ weights. Weights that sum to 0 are rejected. Negative weights are allowed mathematically but rarely make sense for grades. The unweighted average page treats every number equally (weight 1).
Values: Numbers in order, for example 18, 24, 30.
Weights: One weight per value, same order, for example 1, 1, 2.
Weighted mean: The weighted average.
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