Math & Statistics · Browser · Free

Weighted Average Calculator

Enter numbers into Data values and weights into Weights, then press Calculate to find the weighted average and the sum of weights.

What this calculator does

Enter numbers into Data values and corresponding weights into Weights. Press Calculate and the answers appear in cards below the button: Weighted average and Sum of weights.

The form computes only when the button is pressed. Results appear in cards below the button. Copy writes a result and its unit to the clipboard. Clear resets the form. Everything runs in the browser and nothing is uploaded.

Reading the results

Each answer sits on its own card. For Data values: 1.5, 2.5 with Weights: 0.5, 1.5 the cards read Weighted average: 2.25 and Sum of weights: 2.

The sum of weights is reported alongside the weighted average because it is the number the weighted total is divided by. With Data values: 70, 80, 90 and Weights: 2, 3, 1 the cards read Weighted average: 78.3333333333333 and Sum of weights: 6.

Weighted average formula

Multiply each data value by its weight, add those products together, and divide the total by the sum of the weights. A value with a larger weight contributes more to that total than a value with a smaller one.

For Data values: 70, 80, 90 and Weights: 2, 3, 1 that works out to (2 × 70 + 3 × 80 + 1 × 90) / (2 + 3 + 1) = 470 / 6 ≈ 78.3333333333333.

For Data values: 10, 20 and Weights: 1, 3 it is (1 × 10 + 3 × 20) / (1 + 3) = 70 / 4 = 17.5.