Weighted Average Calculator (Values and Weights)

How it is calculated

Each value is multiplied by its own weight, the products are added up, and the sum is divided by the total of the weights.

x̄ = (v₁·w₁ + v₂·w₂ + … + vₙ·wₙ) ÷ (w₁ + w₂ + … + wₙ)

v are the values (any unit, such as points or percent) and w the weights. Weights can be percentages, credits or any non-negative numbers; only their proportions matter, so they do not need to add up to 100. Separate numbers with commas, spaces or semicolons. A decimal point always works inside a number; a decimal comma such as 1,5 is read as 1.5 only when the entries are separated by spaces or semicolons (for example 88; 76,5; 93). Both lists must have the same number of entries. The average is shown to 4 decimals and the total weight to 2. There is no result if the lists differ in length, an entry is not a number, any weight is negative, or the weights add up to zero.

Common mistakes

• Putting the lists in a different order, so a score is paired with another item's weight. The first value always pairs with the first weight.
• Entering a different number of weights than values; the tool then gives no result instead of guessing.
• Typing weights with a percent sign (30%) or as a negative number. Enter plain non-negative numbers such as 30; a % sign or a negative weight gives no result.
• Mixing up decimal commas and separating commas. In a list written only with commas, such as 1,5,2, every comma separates entries, so it is three numbers; to use a decimal comma separate the entries with spaces or semicolons (1,5 2 or 1,5; 2), or simply write 1.5.
• Expecting weights to add up to 100. They do not have to, but then the total weight shown is not 100 and the average is still correct.