Weighted Average Calculator (Values and Weights)

About this calculator

A weighted average gives each value in a list its own level of importance instead of treating all values equally: it’s calculated as the sum of each value multiplied by its weight, divided by the sum of all the weights — Σ(value × weight) ÷ Σ(weight). This differs from a simple average, which implicitly gives every value the same weight of 1, and it matters whenever some inputs should count for more than others.

Teachers and students use weighted averages to calculate course grades where exams count more than homework, investors use them to find the average cost basis or return of a portfolio where different holdings represent different amounts of capital, and statisticians use them when combining survey data or measurements that carry different sample sizes or reliability levels.

This calculator takes a list of values and their matching weights and returns the resulting weighted average.