Weighted Average Calculator
Calculate the weighted average (weighted mean) where individual observations contribute proportional influence based on assigned weights, credits, or volume allocations.
List of numerical values, scores, or returns
Corresponding weight, credit, or percentage for each value
Sum of (value × weight) divided by sum of weights
How to Use This Calculator
- Enter values separated by commas or spaces.
- Enter the corresponding weights in matching sequential order.
- Review the weighted average alongside the unweighted simple mean.
Formula & Calculation Methodology
Each value x_i is multiplied by its corresponding weight w_i. The sum of these products is divided by the aggregate weight total Σw_i.
Worked Example
Class grading: 85 (20%), 90 (20%), 75 (30%), 95 (30%)
Credit weighted GPA: Grade 4.0 (3 credits), Grade 3.0 (4 credits)
Frequently Asked Questions
Do weights need to add up to 100?↓
No. The formula automatically divides by the sum of weights Σw, so credits (e.g. 3, 4, 1) or counts work just as well as percentages.
What occurs if there are more values than weights?↓
The engine evaluates items up to the shortest list length, pairing values with weights index-by-index.
Can weights be negative?↓
Standard physical weights in statistics, grading, and portfolios must be non-negative. Negative weights can cause indeterminate or zero denominators.
What is a limitation of the weighted average?↓
It relies completely on the subjective validity of the assigned weights; distorted weighting produces distorted results.
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Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.