01
How to use this calculator
- List each value beside its weight.
- Multiply each value by its corresponding weight.
- Divide the sum of those products by the sum of weights.
02
A little understanding goes a long way.
A weighted average gives larger influence to values with larger weights. Weights may be counts, proportions or percentages, provided they use a consistent scale.
THE FORMULA
Weighted mean = Σ(value × weight) ÷ Σweights
TRY IT ON PAPER
A worked example
Scores of 80 and 90 with weights of 40% and 60% produce (80 × 0.4) + (90 × 0.6) = 86.
03
A few common questions
Must weights total 100?
Only if your chosen convention requires it. Dividing by the total weight also works for weights such as 2, 3 and 5.
How is it different from the mean?
An ordinary mean gives every value the same weight. A weighted mean allows the influence of each value to differ.