Weighted Average Calculator

1. Enter your values, separated by commas.
2. Enter a weight for each value, in the same order.
3. Read the weighted average.
4. Compare it with the simple average and see the total weight.

Here is what each result means:

A weighted average is a mean where some values count more than others. Instead of adding the values and dividing by how many there are, you multiply each value by a weight, add those products, and divide by the total weight. Values with larger weights pull the average toward themselves.

This matters whenever items are not equally important. A course grade where the final exam is worth more than a quiz, a price averaged over different quantities, or a rating averaged over many reviews all call for a weighted average. When every weight is equal, the weighted average is just the simple mean.

The weighted average always lands somewhere between the smallest and largest of the values, never outside that range. Where exactly it falls depends on where the heavy weights sit: put more weight on the high values and it rises, put more on the low values and it falls. That is what makes it a fair summary when some numbers deserve more say than others.

It multiplies each value by its weight, adds those, and divides by the total weight.

1. Multiply each value by its weight.
2. Add all those products together.
3. Divide by the sum of the weights.

For a grade-specific version that uses credits as weights, the weighted GPA calculator applies the same idea to courses.

Average the scores 90, 80 and 70 with weights 3, 2 and 1.

Calculation: the weighted total is 90(3) + 80(2) + 70(1) = 500, and the total weight is 6, so the weighted average is 500 / 6 = 83.3. The simple average would be 80, so the heavier weight on 90 pulls the result up.

The two agree only when all weights are equal.

When some items matter more, only a weighted average reflects that. With equal weights, the two are the same number.

Weights stand for how much each value should count.

Weights do not need to add to 100 or any set total; only their relative sizes matter.

The Size of the Weights

Only the relative weights matter. Doubling every weight leaves the average unchanged.

Which Values Are Heavy

A large weight on a high value pulls the average up; a large weight on a low value pulls it down.

The Spread of Values

When the values are far apart, the weights make a bigger difference to the result.

Grades and Scores

Combine assignments and exams that are worth different amounts.

Prices and Costs

Average unit prices across different quantities bought.

Ratings and Surveys

Average scores that have different numbers of responses.

1. Using a Simple Average by Mistake

If items count differently, a plain mean is wrong. Use the weights.

2. Forgetting to Divide by Total Weight

Divide by the sum of the weights, not by the number of values.

3. Mismatched Values and Weights

Each value needs its own weight in the same order.

4. Thinking Weights Must Total 100

Only relative weights matter. They can be any positive numbers.

5. Using Negative Weights

Ordinary weighted averages use non-negative weights that are not all zero.

The formula is exact; only the displayed decimals are rounded.

It is a mean where each value counts by a weight instead of equally. Multiply each value by its weight, add the products, and divide by the total weight. Heavier values pull the average toward them.

Multiply each value by its weight, sum those products, and divide by the sum of the weights. Scores 90, 80, 70 with weights 3, 2, 1 give 500 over 6, about 83.3.

A simple average counts every value equally. A weighted average lets some values count more. They match only when all the weights are equal.

No. Only the relative sizes of the weights matter, so they can be any non-negative numbers. Weights of 3, 2, 1 give the same result as 30, 20, 10.

Use whatever reflects importance: the percentage each grade is worth, the quantity bought at each price, or the number of reviews at each rating.

Ordinary weighted averages use non-negative weights. Negative weights can make the result behave strangely, so this tool does not allow them.

Then the weighted average equals the simple average, since every value counts the same. The weights only change the result when they differ.

Because each value contributes in proportion to its weight, not as one equal share. Dividing by the total weight scales the sum back to the value range.

No. The calculation runs in your browser and nothing you enter is stored or sent anywhere, unless you choose Save, which keeps the result only on this device.

• Weighted arithmetic mean (Wikipedia).
• Weighted mean explained (Maths Is Fun).
• Mean (Wikipedia).