Quick Presets
| # | Label (optional) | Value | Weight | Weight % |
|---|
Weighted Average
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💡 Note: Weights do not need to add up to 100% — the calculator normalizes them automatically. You can use percentages, credit hours, or any relative numbers as weights.
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Sources & Methodology
Weighted average formula verified against standard mathematical and statistical references from Khan Academy and NCTM.
Khan Academy — Weighted Mean & Statistics
Mathematical foundation for weighted average calculations and mean calculations
National Council of Teachers of Mathematics (NCTM)
Curriculum standards for weighted average calculations used in educational settings
Methodology: Weighted Average = Σ(Value × Weight) ÷ Σ(Weight). Each value is multiplied by its corresponding weight, all products are summed, then divided by the total sum of weights. Weight percentages are calculated as (individual weight ÷ total weight) × 100.
⏱ Last reviewed: March 2026
How to Calculate a Weighted Average
A weighted average gives different values different levels of importance based on assigned weights. Unlike a simple average that treats all values equally, a weighted average reflects the relative significance of each item.
The Formula
Weighted Average = Σ(Value × Weight) ÷ Σ(Weight)
Example: Three test scores — 80 (weight 2), 90 (weight 3), 85 (weight 1)
= (80×2 + 90×3 + 85×1) ÷ (2+3+1)
= (160 + 270 + 85) ÷ 6
= 515 ÷ 6 = 85.83
= (80×2 + 90×3 + 85×1) ÷ (2+3+1)
= (160 + 270 + 85) ÷ 6
= 515 ÷ 6 = 85.83
Common Uses of Weighted Averages
| Use Case | Values | Weights |
|---|---|---|
| Course Grade | Assignment scores | % of final grade |
| GPA Calculation | Grade points (A=4, B=3…) | Credit hours per course |
| Investment Portfolio | Return % per asset | Dollar value invested |
| Employee Review | Scores per category | Importance of each category |
| Price Index | Price of each item | Quantity sold |
| Survey Results | Response scores | Number of respondents |
Weighted Average vs Simple Average
The key difference: a simple average gives equal importance to all values. A weighted average allows some values to count more than others. For example, if your final exam is worth 40% of your grade and a homework assignment is worth 5%, the final has 8× more impact — a simple average would ignore this completely.
💡 Pro Tip: Weights don't need to add up to 100. You can use any numbers — the formula normalizes them. Using 40, 30, 30 gives the same result as 0.4, 0.3, 0.3 or 4, 3, 3. Use whatever is most natural for your situation.
Frequently Asked Questions
Multiply each value by its weight, add all the products together, then divide by the sum of all weights. Formula: Weighted Average = Σ(Value × Weight) ÷ Σ(Weight). Example: scores of 80 (weight 2) and 90 (weight 3) = (80×2 + 90×3) ÷ (2+3) = (160+270) ÷ 5 = 86.
A simple average treats all values equally. A weighted average gives more importance to values with higher weights. For example, a final exam worth 50% of your grade has far more impact on your course grade than a quiz worth 5%. A simple average of the two scores would be misleading.
No — weights can be any positive numbers. The formula divides by the sum of weights automatically, so 40+30+30=100, 4+3+3=10, and 0.4+0.3+0.3=1 all give identical results. Use whatever unit is most natural — percentages, credit hours, dollar amounts, or arbitrary numbers.
Multiply each course's grade points (A=4.0, B=3.0, etc.) by its credit hours, sum all the products, then divide by total credit hours. Example: Course A (3.7 grade × 4 credits = 14.8) + Course B (3.0 × 3 credits = 9.0) = 23.8 ÷ 7 credits = 3.4 GPA. This calculator handles this automatically — just enter grade points as values and credit hours as weights.
Use a weighted average whenever different items have unequal importance or size. Classic examples: course grades with different assignment weights, investment portfolio returns (weighted by dollar amount), employee performance reviews with different criteria importance, and price indexes. If all items are equally important, a simple average is sufficient.
In finance, weighted averages are used for portfolio return calculation (each holding's return weighted by its value), Weighted Average Cost of Capital (WACC), weighted average cost of inventory, and price-weighted vs. market-cap-weighted indexes. The S&P 500 is a market-cap-weighted index — larger companies have more influence on the index value.
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