Weighted Average Calculator

A weighted average is a mean calculated by assigning different levels of importance (weights) to each data point. Unlike a simple average where all values contribute equally, a weighted average multiplies each value by its corresponding weight, sums the results, and divides by the total sum of weights. This gives more influence to values with higher weights.

A simple average treats all data points equally — you just add them up and divide by the count. A weighted average accounts for the relative importance or frequency of each value. For example, if a final exam is worth 50% of your grade but a quiz is only worth 10%, a weighted average reflects that difference accurately while a simple average would not.

The formula is: Weighted Average = (w₁×x₁ + w₂×x₂ + ... + wₙ×xₙ) / (w₁ + w₂ + ... + wₙ), where x represents each data value and w represents its corresponding weight. You multiply each value by its weight, sum all those products, then divide by the total sum of all weights.

Not always — it depends on the context. A weighted average is better when data points have unequal importance or frequency, such as grading systems, financial portfolios, or survey results with different sample sizes. If all items are equally important, a simple average is perfectly appropriate and easier to compute.

Finance uses weighted averages extensively. Common examples include the Volume-Weighted Average Price (VWAP) of a stock, weighted average cost of capital (WACC), weighted average portfolio returns (where each asset is weighted by its share of the total portfolio), and inventory cost methods like weighted average cost (WAC).

No, the weights do not need to sum to 100 or any specific number. They can be any positive values — percentages, counts, frequencies, or arbitrary importance scores. The calculator automatically divides the total weighted sum by the sum of all weights, so the scale of the weights does not affect the final result as long as their relative proportions are correct.

To calculate a weighted average portfolio return, assign each asset's weight as its proportion of the total portfolio value (e.g., a stock worth $6,000 in a $10,000 portfolio has a weight of 0.6 or 60%). Multiply each asset's return by its weight, then sum all the products. This gives the overall portfolio return adjusted for how much of your money is in each investment.

Yes. Enter each assignment, quiz, or exam score as a value and its percentage weight in the course as the weight (e.g., 85 with weight 30 for a 30% assignment). The calculator will compute your weighted course average, showing exactly how each component contributes to your final grade.