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Weighted Average Calculator

This weighted average calculator finds the mean when some values count more than others, such as grades with different weightings. Enter the values and their weights; it multiplies, adds and divides, showing each step.

Separate values with commas or spaces.
Weights can be percentages, credits or counts.

Result

Enter values and press Calculate to see the result.

Formula

xˉw=∑wixi∑wi\bar{x}_w = \frac{\sum w_i x_i}{\sum w_i}

Multiply each value by its weight, add the results, then divide by the total weight.

How to use this calculator

  1. Enter the values, then their weights in the same order.
  2. Weights do not need to add up to 1 or 100: the calculator divides by their total.
  3. Press Calculate to see the weighted average and the working.

Worked examples

Marks 80, 90 and 70 with weights 2, 3 and 5

80 × 2 + 90 × 3 + 70 × 5 = 160 + 270 + 350 = 780.

The weights add up to 10, so the weighted average is 780 ÷ 10 = 78.

Percent weights: 72 (40%) and 85 (60%)

72 × 40 + 85 × 60 = 2880 + 5100 = 7980.

7980 ÷ 100 = 79.8.

Common mistakes

  • Taking the ordinary mean, which treats every value as equally important.
  • Dividing by the number of values instead of the total weight.
  • Listing weights in a different order from the values.

Frequently asked questions

How do you calculate a weighted average?

Multiply each value by its weight, add these products, and divide by the sum of the weights.

Do the weights have to add up to 100%?

No. Dividing by the total weight takes care of it: weights 2, 3, 5 work the same as 20%, 30%, 50%.

When is a weighted average used?

Course grades with weighted assignments, grade point averages with credit hours, and averaging prices bought in different quantities.