Calculate Any Weighted Average Instantly
Add your values and weights, hit Calculate — get the weighted mean, each item’s contribution, and full step-by-step working. Works for GPA, investments, surveys, and any scenario where values matter differently.
What Is a Weighted Average?
A weighted average is a calculation that assigns different levels of importance to each value in a dataset before finding the mean. In a standard arithmetic mean, every number counts equally. A weighted average changes that — values with higher weights pull the result more strongly in their direction.
Think about how a university calculates your final grade. A 10-credit module should count for more than a 5-credit one, even if both have the same percentage score. A simple average would treat them identically and give you an inaccurate result. A weighted average — using credit hours as the weight — gives you the number that actually reflects your academic performance. The same logic applies in finance, business analytics, and data science.
The Weighted Average Formula
// Σ means “sum of all”
WA = (70×1 + 80×2 + 90×3) ÷ (1+2+3) = 490 ÷ 6 = 81.67
Weighted Average vs. Simple Average
| Situation | Simple Average | Weighted Average |
|---|---|---|
| All values equally important | ✓ Correct | ✗ Unnecessary |
| Values from different sample sizes | ✗ Inaccurate | ✓ Correct |
| Grades with different credit hours | ✗ Misleading | ✓ Correct |
| Investment portfolio with different allocations | ✗ Inaccurate | ✓ Correct |
| Survey scores from groups of different sizes | ✗ Biased | ✓ Correct |
Not sure which average to use? Our guide on mean vs median vs average explains the differences with real examples.
How to Calculate a Weighted Average — Step by Step
- List all the values you want to include — exam scores, returns, ratings, or any numbers.
- Assign a weight to each value that reflects its relative importance. Weights can be percentages, credit hours, investment sizes, or any positive number.
- Multiply each value by its corresponding weight.
- Add all the weighted values together to get the sum of products.
- Add all the weights together to get the total weight.
- Divide the sum of products by the total weight. That is your weighted average.
Tip: Your weights do not need to add up to 100. Using weights of 1, 2, 3 gives exactly the same result as 25%, 50%, 75% — because the formula divides by the total weight automatically.
Real-World Uses of Weighted Average
GPA & Grade Averages
Weight each subject grade by its credit hours. Use our grade average calculator for automatic GPA conversion too.
Investment Portfolios
Weight each asset’s return by its allocation. See also: stock average calculator for cost basis averaging.
Survey Analysis
When survey groups have different sample sizes, weight each group’s average by its sample count for an accurate overall result.
Stock Cost Averaging
When buying shares at different prices, weight each price by the number of shares. Try the stock average calculator for this.
WACC Calculation
Weighted average cost of capital weights each funding source (debt, equity) by its proportion of total financing.
Review Score Averages
Weight star rating counts so 500 five-star reviews carry more influence than 10 one-star reviews. Use our average score calculator.
Weighted Average in Excel and Google Sheets
If you prefer a spreadsheet, use the SUMPRODUCT function. With values in A2:A6 and weights in B2:B6:
// Works identically in Excel and Google Sheets
Our calculator does the same thing instantly — no spreadsheet setup needed, with full working shown automatically.