ClarityKitFind a tool
Math

Weighted Average Calculator

Find an average when observations have different weights.

Exact method explained belowEditable inputs

Set up your calculation

Runs on your device

SOLUTION

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter values, matching weights.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Weighted mean = Σ(value × weight) ÷ Σweights. Match each value with the weight at the same position.

A WORKED EXAMPLE

Scores of 80 and 90 with weights 1 and 3 have a weighted average of 87.5.

What to keep in mind

Weights must be nonnegative and at least one positive. Both lists must have the same length. Use a dot for decimals and no thousands separators.

Common questions

Must weights add up to 100?

No. Relative weights work; 1 and 3 give the same result as 25 and 75.

Can a value have zero weight?

Yes. It contributes nothing to the weighted sum but still needs a matching list position.

Methodology maintained by ClarityKit. How these tools are built and checked.