Weighted Average Calculator
Use this when items count unequally, such as marks with different shares of a final grade.
Weighted average
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Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Values read in each list —
Unweighted average —
Total weight —
Reading this —
The formula
weighted average = Σ(value × weight) ÷ Σ(weight)
With equal weights this is the ordinary mean.
What to watch out for
Multiply each value by its weight, add the results and divide by the total weight. The weights can be percentages, credits or counts.
Frequently Asked Questions
Do the weights have to add up to 100?
No. The division handles any total. Weights 2, 3, 5 give the same answer as 20, 30, 50.
What is a worked example?
Marks of 70, 85 and 90 weighted 20, 30 and 50 average 84.5, against a plain mean of 81.6667.