Weighted average calculator

Enter values and weights in the same order, separated by commas. The calculator computes Σ(w·x)/Σw. 80 and 90 with weights 2 and 1 give 83.33. 4, 5 and 6 with equal weights give 5.

A single pair works too: 80 with weight 2 stays 80, because 160/2 = 80. If the weight count does not match the value count, the result stays blank.

Input data

Results

Enter data and click Calculate.

How it works

A weighted average is the sum of each value times its weight, divided by the sum of the weights. The calculator reads both lists in the same order. 80 and 90 with weights 2 and 1 give (160 + 90) / 3 = 83.33.

A single pair is valid too: 80 with weight 2 is 160/2 = 80. Equal weights reduce the formula to a plain mean: 4, 5 and 6 with weights 1, 1 and 1 give 5.

The two lists must have the same length. If the weights do not add up to a number other than zero, the result stays blank. A comma, a space, or a semicolon separates the numbers.

This is not an ECTS average and not an arithmetic mean from one field. Those tools sit next door when you need credit-weighted grades or a list without weights.

Formula

average = Σ(w·x) / Σw

How to use

  1. Enter the values, for example 80, 90.
  2. Enter the weights in the same order, for example 2, 1.
  3. Click Calculate. The result is 83.33.
  4. 4, 5 and 6 with weights 1, 1 and 1 give 5.
  5. 10 and 20 with weights 1 and 3 give 17.5.

80 and 90 with weights 2 and 1 give 83.33

The calculator computes Σ(w·x)/Σw. One pair or several pairs, as long as the lists have the same length.

values
The first field. 80, 90 or a single number, for example 80.
weights
The second field, in the same order. 2, 1 or a single weight, for example 2.
average
The sum of products divided by the sum of weights. 80 and 90 with 2 and 1 give 83.33.

Examples

Example 1

  • 80, 90
  • 2, 1

83.33

What do 80 and 90 with weights 2 and 1 give? 83.33. That is (160 + 90) / 3.

Example 2

  • 4, 5, 6
  • 1, 1, 1

5

What do 4, 5 and 6 with equal weights give? 5. Equal weights become a plain mean.

Example 3

  • 10, 20
  • 1, 3

17.5

What do 10 and 20 with weights 1 and 3 give? 17.5. The larger weight pulls the mean toward 20.

Related calculators

Arithmetic mean calculator

Arithmetic mean calculator: a list of numbers in one field, with spaces or commas.

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Geometric mean

Geometric mean: two numbers.

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Common questions

What do 80 and 90 with weights 2 and 1 give?

83.33. The calculator computes (160 + 90) / 3.

Is this Σ(w·x)/Σw?

Yes. The sum of each value times its weight, divided by the sum of the weights.

What do 4, 5 and 6 with weights 1, 1 and 1 give?

5. Equal weights become a plain arithmetic mean.

What do 10 and 20 with weights 1 and 3 give?

17.5. The larger weight on 20 raises the mean.

What if the weights do not match the values?

The result stays blank. The two lists must have the same length.

What if the weights add up to 0?

The result stays blank. The calculator does not divide by zero.

Knowledge sources

The calculator computes Σ(w·x)/Σw from the value and weight lists.

Page updated in 2026.