Weighted Average Calculator
Calculate a weighted average from values and their weights.
Last updated · View algorithm, constants and default inputs (JSON)
Weighted average: 87.10
About this calculator
A weighted average pairs each value with the weight in the same position. Both lists must contain the same number of finite values; weights must be non-negative and have a positive total. Separate entries with commas or spaces. In locales that use decimal commas, separate entries with semicolons (for example, 1,5; 2,5).
Worked example
calculated with the default values below
Values (comma/space; semicolon for decimal comma) 85, 92, 78 · Weights (comma/space; semicolon for decimal comma) 0.3, 0.5, 0.2 Weighted average 87.1000 · Total weight 1.0000 · Simple average 85.0000 · Number of values 3
General background references
Disclaimer
These calculators give general mathematical results. They suit study, planning and estimation — verify anything that feeds a graded submission, a published figure or a financial commitment.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
x̄_w = Σ (x_i × w_i) ÷ Σ w_i
- x_i
- Values list
- w_i
- Weights list
- n
- Paired count
- x̄_w
- Weighted average
Lists must have equal lengths; entries pair by index. Weights must be nonnegative with Σw>0. Separate with commas/spaces for decimal-point values; with decimal commas, use semicolons between entries (commas within numbers are converted to decimal points). Inputs are limited to 1,000 entries.
Frequently asked questions
Why is the simple average also shown?
The simple average gives every entered value equal weight. The weighted average instead multiplies each value by its matching non-negative weight and divides by the positive sum of weights; a zero total is invalid.