Weighted Average Calculator
Combine values with their weights into a weighted average — for grades, prices, portfolios or any figures that do not count equally.
How it works
Weighted average = Σ(value × weight) ÷ Σ(weight)
A weighted average lets some numbers count more than others by multiplying each value by a weight, summing, and dividing by the total weight. It is the right tool whenever items differ in importance, size or frequency — course grades by credit hours, share prices by number of shares, or survey answers by group size. When every weight is equal, it collapses back to the ordinary mean.
Worked example
Scores of 90, 80 and 70 with weights 0.5, 0.3 and 0.2 give 90 × 0.5 + 80 × 0.3 + 70 × 0.2 = 45 + 24 + 14 = 83. The weights already sum to 1, so the weighted average is 83 — higher than the simple average of 80 because the top score carries the most weight.
Sources: Weighted arithmetic mean — Wikipedia
Frequently asked questions
Do the weights have to add up to 1?
No. The formula divides by the total weight, so any positive scale works — weights of 5, 3, 2 give the same result as 0.5, 0.3, 0.2. Percentages, counts and raw importance scores are all fine.
How do I use this for a GPA or course grade?
Enter each assessment’s score as a value and its share of the grade (or its credit hours) as the weight. The weighted average is then the overall grade, correctly reflecting that a final exam worth 40% counts more than a quiz worth 5%.
What happens with a zero weight?
An item with a weight of zero drops out entirely — it contributes nothing to the numerator and nothing to the total weight, exactly as if it were not listed.
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