Weighted Average Calculator
Calculate a weighted average (weighted mean) from values and their weights. Ideal for grades, ratings, portfolios and survey data.
Last reviewed by the Radiatus Cloud team
Compute a weighted mean where each value counts according to its weight.
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Calculate a weighted average
A weighted average, or weighted mean, is an average in which some values count more than others according to a weight. Each value is multiplied by its weight, the products are added together, and the total is divided by the sum of the weights. When all weights are equal this reduces to the ordinary average, but when they differ the result reflects the greater importance of the heavily weighted values.
Enter your values and a matching list of weights in the same order. The calculator shows the weighted mean along with the weighted total, the total weight, and the plain unweighted average so you can compare the two.
Common weighted-average problems
Weighted means appear everywhere importance varies. Teachers combine test, coursework and exam scores that each count for a different percentage. Investors find a portfolio return from holdings of different sizes. Shoppers average product ratings that have different numbers of reviews. Survey analysts weight responses to match a population.
The values and weights must have the same number of entries, and the total weight must not be zero. Weights can be whole numbers, percentages or any positive figures, since only their relative sizes matter. All calculation happens locally in your browser.
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Frequently Asked Questions
How is a weighted average calculated?
Multiply each value by its weight, add those products, then divide by the sum of the weights. Equal weights give the ordinary average.
Do the weights have to add up to 100?
No. Only the relative sizes of the weights matter, so you can use percentages, credit hours, counts or any positive numbers.
What if I have more values than weights?
Every value needs a matching weight in the same order. The tool asks you to fix the lists if the two counts differ.
Can weights be decimals?
Yes. Weights and values can both be decimals. Avoid a total weight of zero, which would make the average undefined.
How does it differ from a normal average?
A normal average treats every value equally. A weighted average lets chosen values influence the result more, according to their weights.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Enter values and matching weights, one pair per line or as comma lists.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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