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Weighted Average Calculator

Enter values and their weights to get the weighted mean, with the total weight and the plain average shown for comparison. Updates as you type.

Values and weights

Values and weights can be whole, decimal, or negative. Calculated in your browser. Nothing is uploaded.

Weight mode
Weighted average

3 values used

Weighted average
87.5
value × weight, summed and divided by the total weight
88.3333
Arithmetic mean
unweighted average
6
Total weight
sum of weights
3
Values counted
rows used
Weight distribution
  • Value 903 (50%)
  • Value 802 (33.33%)
  • Value 951 (16.67%)

How to calculate a weighted average

  1. Enter values and weights

    Type each value and its weight into a row, adding or removing rows as you need them.

  2. Read the weighted average

    The weighted average, total weight, and plain arithmetic mean update automatically as you type.

  3. Compare and copy

    Switch the weights to percentages to see each share, then copy the full summary with one click.

Why use this tool

Weighted mean, instantly

Enter any number of value and weight pairs and the weighted average is recalculated the moment you type. There is no run button to press.

Plain average for comparison

The unweighted arithmetic mean is shown next to the weighted result, so you can see how much the weights move the number.

Weights as percentages

Switch to percentage mode to normalize the weights to 100% and read each value share of the total weight.

Handles messy input

Blank or half filled rows are skipped, and a total weight of zero is caught instead of showing an undefined result.

Weight distribution at a glance

Each row shows its share of the total weight with a small bar, so you can see which values dominate the average.

Runs entirely in your browser

Everything happens on your device. The numbers you enter are never uploaded, stored, or logged.

About this tool

A weighted average gives some values more influence than others. Instead of adding the numbers and dividing by how many there are, each value is multiplied by a weight, those products are summed, and the total is divided by the sum of the weights. This calculator does that for any list of value and weight pairs: enter a value and its weight on each row, add or remove rows freely, and the weighted mean updates as you type. It fits grades weighted by credit hours, review scores weighted by importance, prices weighted by quantity, or survey results weighted by sample size.

Alongside the weighted average you get the total weight, the number of rows used, and the plain arithmetic mean, so you can see exactly how much the weights shift the result. Values and weights can be whole numbers, decimals, or negative, and rows that are blank or only half filled are skipped rather than breaking the calculation. If the weights add up to zero the weighted average is undefined, so the tool says so instead of showing a misleading figure. Turn on percentage mode to normalize the weights to 100% and read each value share of the total, which helps when your weights are meant to be proportions.

Everything runs in your browser and nothing is uploaded. For a straight mean, median, and mode of a list, use the average calculator. To weight course grades by credit hours on a 4.0 scale, the GPA calculator is purpose built, and the percentage calculator handles shares and changes.

Frequently asked questions

How is a weighted average calculated?
Multiply each value by its weight, add up all of those products, then divide by the sum of the weights. For example, values 90, 80, and 95 with weights 3, 2, and 1 give (90x3 + 80x2 + 95x1) divided by (3 + 2 + 1), which is 525 divided by 6, or 87.5.
What is the difference between a weighted average and a normal average?
A normal, or arithmetic, average adds the values and divides by the count, treating every value equally. A weighted average lets each value carry a different weight, so values with larger weights pull the result toward themselves. This tool shows both figures side by side.
What if my weights do not add up to 100?
That is fine. Scaling every weight by the same amount does not change the weighted average, because the tool always divides by the sum of the weights. Percentage mode simply normalizes your weights to add up to 100% so you can read each share more easily.
What happens if the total weight is zero?
The weighted average is undefined when the weights sum to zero, since that would mean dividing by zero. Rather than showing a broken result, the tool flags it and asks you to give at least one row a weight that is not zero.
Can I use decimals or negative numbers?
Yes. Values and weights can be whole numbers, decimals, or negative. Rows left blank or with only one field filled are skipped and counted so you can see how many values were actually used.
Is my data uploaded anywhere?
No. Everything runs in your browser; nothing is sent to a server. The values and weights you enter are never uploaded, stored, or logged.

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