Calculators
Weighted Average Calculator
Calculate a weighted average from value and weight pairs with relative weights, counts, or percentages in your browser.
Give each value its appropriate share of the average.
The weighted average is Σ(value × weight) divided by Σ(weight). For example, values 80, 90, and 100 with weights 20, 30, and 50 have a weighted sum of 9300 and total weight of 100, giving an average of 93. Weights may be counts, proportions, or percentages and do not need to add up to 100. Zero weights contribute nothing; negative weights are rejected. Values may be negative. Use consistent units for all values and a consistent weight scale. Results use browser floating-point arithmetic and display up to 12 significant digits. Everything runs locally without uploading or storing your data.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
How do you calculate a weighted average?
Multiply each value by its weight, add those products, and divide by the sum of all weights. For 80 with weight 20, 90 with weight 30, and 100 with weight 50, the result is (1600 + 2700 + 5000) / 100 = 93.
Do the weights have to add up to 100?
No. Weights are relative: 2, 3, and 5 give the same average as 20, 30, and 50 or 0.2, 0.3, and 0.5. Use the same scale for every weight.
Can values or weights be negative or zero?
Values can be negative or zero. Weights must be nonnegative, with at least one positive weight. A zero weight excludes its value from the weighted sum and average.
How is this different from a regular average?
A regular arithmetic mean gives every value equal importance. A weighted mean gives larger weights more influence. Equal positive weights produce the regular mean.
How do I enter the data?
Enter one value and weight pair per line, separated by a comma, semicolon, or spaces. Use decimal points without thousands separators. Scientific notation is supported. All calculations run in your browser.