Weighted Values Mean Calculator

Find a weighted mean from matching value and non-negative weight lists. A larger weight gives an observation more influence.

How to use Weighted Values Mean Calculator

1. Enter Values and Weights as matching lists where weights are used; separate numbers with commas, spaces, semicolons or new lines. 2. Keep all observations on one unit or scoring scale. 3. Select Calculate or press Enter, then read weighted mean. 4. Copy result copies the answer; Reset clears the form. Do not use thousands separators inside lists.

Why use this tool?

Combine comparable values with known frequencies or importance weights instead of assuming every entry has equal influence.

How the calculation works

Weighted mean = sum(value × weight) ÷ sum(weights). At least one weight must be positive; zero-weight entries contribute nothing. The result uses the same unit as the values. Weights may be relative proportions and do not need to add to 1 or 100. Results use up to six decimal places, or six significant digits in scientific notation for nonzero magnitudes below 0.000001. Calculations use browser floating-point arithmetic. Each list supports up to 20,000 numbers. Entry and result magnitudes must not exceed 9,007,199,254,740,991; unrepresentable variance or weighted products are rejected. General descriptive-statistics reference: https://www.itl.nist.gov/div898/handbook/eda/section3/eda351.htm. Weighted conventions are defined explicitly on this page.

Example

Values = 60,80,100 and Weights = 1,2,1 give (60 + 160 + 100) ÷ 4 = 80.

Practical tip

Keep values and weights in matching order. Multiplying every weight by the same positive factor leaves the mean unchanged.