Weighted Average Calculator

A mean in which each value carries a weight reflecting its importance. Instead of treating every value equally, it multiplies each by its weight before averaging, so heavier items influence the result more.

A normal (arithmetic) mean adds the values and divides by how many there are — every value counts the same. A weighted average lets values count by different amounts. They coincide only when all weights are equal.

Weighted average = Σ(value × weight) ÷ Σweight. Multiply each value by its weight, add the products, and divide by the sum of the weights.

One pair per line, value first then weight, separated by a space or semicolon — for example "90 40". Do not use a comma between them, because a comma is read as a decimal separator inside a number.

No. They can be any non-negative numbers — percentages, credit hours, counts, anything. The formula divides by their total, so 40 and 60 give the same result as 0.4 and 0.6.

Yes. A weight of 0 removes that value from the average without deleting the line. At least one weight must be positive, though, otherwise the total weight is zero and there is nothing to divide by.

Values can be negative, but weights cannot — a negative weight has no sensible meaning here and is rejected. Use a weight of 0 to exclude something instead.

To make the effect of weighting visible. Comparing the weighted result with the plain mean shows how much the weights shifted the answer.

Weighted course grades and GPAs, blended review scores, portfolio returns, survey results with different sample sizes — anywhere items should count in proportion to their importance.

Yes. Everything is calculated in your browser; the values and weights you enter are never uploaded.