Weighted Average Calculator
Calculate weighted average from values and weights. GPA, portfolio returns, grades. Free calculator.
When to Use Weighted Average
Use weighted average when data points have different importance. GPA: A grade in a 4-credit course matters more than a 2-credit course. Portfolio returns: A stock that is 40% of your portfolio matters more than one that is 5%. Survey results: Responses from a larger sample should weigh more. Simple averages treat everything equally — weighted averages reflect reality.
Formula and Example
Weighted average = sum(value x weight) / sum(weights). Three test scores: 85 (weight 3), 92 (weight 4), 78 (weight 2). Calculation: (85x3 + 92x4 + 78x2) / (3+4+2) = (255 + 368 + 156) / 9 = 86.6. The simple average (85+92+78)/3 = 85.0 is different because it ignores the weights.
Your GPA, the S&P 500, and your credit score are all weighted averages. The S&P 500 is weighted by market cap. Your credit score weights payment history at 35%, utilization at 30%, length at 15%.
