Weighted Average Calculator
Calculate weighted averages online for free. Our weighted average calculator supports up to 20 value-weight pairs with optional labels. Enter your values and weights to get the weighted mean, each item's contribution, a visual breakdown, and a comparison with the simple average. No signup required - all calculations run locally in your browser.
Enter up to 20 values with their weights. Labels are optional. Weights can be any positive numbers - they do not need to sum to 100. All calculations run locally in your browser.
Why Use Our Weighted Average Calculator?
Accurate Weighted Average Calculation
Computes the weighted mean using the standard formula Σ(Value × Weight) / Σ(Weight). Supports up to 20 items with optional labels. Weights do not need to sum to 100 - they are normalized automatically.
Contribution Breakdown with Visual Bars
See exactly how much each item contributes to the final weighted average, with a proportional bar for each entry. Instantly shows which items carry the most weight in the result.
Fully Private - No Data Sent to Servers
All calculations run locally in your browser. Your values and weights are never transmitted to any server, stored, or tracked. Complete privacy with no signup required.
100% Free, No Installation Required
Use the weighted average calculator directly in any modern browser. No downloads, no plugins, no account needed. Free forever with no usage limits.
Common Use Cases for Weighted Average Calculator
Grade & GPA Calculation
Calculate weighted course grades where exams, assignments, and participation each carry different percentages. Enter each grade as a value and its weight percentage to get your final weighted grade.
Survey & Research Analysis
Aggregate survey scores where different respondent groups represent different population sizes. Use population count as the weight to get a representative weighted mean.
Project Management Scoring
Score project proposals or vendor options where criteria have different importance levels. Assign weights based on business priority and compare weighted scores across candidates.
Portfolio & Investment Averaging
Calculate the weighted average cost or return across investments of different sizes. Use position size or allocation percentage as the weight for each asset.
Health & Fitness Metrics
Combine multiple health indicators that carry different diagnostic importance. Useful for scoring wellness assessments where each metric has a defined clinical weight.
Engineering & Quality Control
Compute composite quality scores where different test results contribute unequally to an overall pass/fail threshold. Standard practice in manufacturing and compliance assessments.
Understanding Weighted Average and How to Calculate It
What is a Weighted Average?
A weighted average is a mean that accounts for the varying importance of different values. Unlike a simple average - where every value contributes equally - a weighted average multiplies each value by its assigned weight before summing. This makes it the correct tool whenever values should not contribute equally to the final result, such as when course grades have different percentage weights or when combining metrics of different sample sizes.
Weighted Average Formula
The formula is: Weighted Average = Σ(Value × Weight) / Σ(Weight)
For example, with three exam scores of 90 (weight 40%), 75 (weight 35%), and 85 (weight 25%):
- Numerator: (90×0.40) + (75×0.35) + (85×0.25) = 36 + 26.25 + 21.25 = 83.5
- Denominator: 0.40 + 0.35 + 0.25 = 1.00
- Weighted Average = 83.5 / 1.00 = 83.5
The weights do not need to sum to 1 or 100. The calculator normalizes them automatically, so weights of (40, 35, 25) give the same result as (0.40, 0.35, 0.25).
Weighted Average vs Simple Average
A simple average divides the sum of values by the count of values. It treats all items equally. A weighted average gives more influence to items with higher weights. They produce the same result only when all weights are equal. Whenever values represent different sample sizes, different importance levels, or different time periods, weighted average is the appropriate measure.
How the Contribution Breakdown Works
The contribution of each item = (Value × Weight) / Total Weight. This shows how much each individual item adds to the final weighted average. The sum of all contributions always equals the weighted average. The percentage weight shows what fraction of the total weight each item carries.
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Frequently Asked Questions About Weighted Average Calculator
A weighted average calculator computes the mean of values where each has a different importance (weight). Our calculator supports up to 20 items with optional labels, shows each item's contribution to the final result, and compares the weighted mean to the simple average.
Weighted Average = Σ(Value × Weight) / Σ(Weight). Multiply each value by its weight, sum the products, then divide by the total weight. Our calculator shows this formula with your actual numbers after each calculation.
No - weights can be any positive numbers. Our weighted average calculator normalizes them automatically. Weights of (40, 35, 25), (0.40, 0.35, 0.25), and (4, 3.5, 2.5) all produce identical results.
Enter each grade component as a value and its percentage weight. For example: Midterm 78 (weight 30), Final 85 (weight 40), Assignments 90 (weight 30). The calculator computes your weighted grade and shows each component's contribution.
Simple average treats all values equally. Weighted average accounts for different importance levels, giving more influence to higher-weight items. They are equal only when all weights are identical. Our calculator shows both so you can compare them directly.
Yes. Weights can be any non-negative decimal number. You can use percentages (30, 40, 30), decimals (0.3, 0.4, 0.3), or any other positive numbers - the calculator normalizes them automatically.
Absolutely. All calculations happen locally in your browser using JavaScript. Your values and weights are never sent to any server, stored, or tracked in any way.
Yes - 100% free with no signup, no usage limits, and no premium features. Calculate as many weighted averages as you need, completely free.