Weighted Average Calculator
Enter paired values and weights to calculate a weighted mean. Inspect normalized weight shares, each contribution and a comparison with the unweighted average.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Pair each value with the weight in the same position. Add weights, divide each weight by their total, multiply the value by its normalized share, then add these contributions. Weights do not need to add to 100.
weighted mean = Σ(value × weight) / Σweight; normalized share = weight / Σweight
Worked example
Values 80, 90 and 70 with weights 20, 30 and 50 give contributions 16, 27 and 35, for a weighted average of 78. The unweighted mean is 80. Weights 2, 3 and 5 give the same weighted result.
Assumptions and input details
Use the same measurement scale for all values. Weights must be non-negative with at least one positive weight; zero-weight entries do not affect the weighted mean. This normalizes the supplied weights and does not assume missing course work is zero or enforce a grading policy. Separate entries with spaces, commas or new lines; commas are separators, not decimal or thousands punctuation. Charts show up to the first 20 entries; the table includes all entries.
References: OpenStax: weighted mean
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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