Weighted Average Calculator
Compute weighted average of up to three values with individual weights. Ideal for grades or blended rates where values contribute unequally to the mean.
How to use this tool
- Enter value 1, weight 1, value 2, weight 2, value 3 and weight 3 in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your weighted average and the full breakdown beneath it.
Formula
WA = sum(vi * wi) / sum(wi)
How it works
Multiply each value by its weight, sum those products, then divide by the total weight: WA = Σ(v·w) / Σw.
Worked example
Grades 80(x1), 90(x2), 70(x1)
- Numerator: 80+180+70 = 330
- Denominator: 1+2+1 = 4
- WA = 330/4 = 82.5
Common mistakes to avoid
- Assigning equal weights to all values when the weights actually differ, effectively computing a simple unweighted average.
- Forgetting to divide the weighted sum by the total weight rather than the count of values.
- Using percentages as weights that do not sum to 100 without normalizing, skewing the result.
Key terms
Frequently asked questions
- Does it matter what units I use for the weights?
- No. Weights are relative. Whether you enter 1/2/3 or 10/20/30, the weighted average is the same because the tool divides by the total weight.
- How is a weighted average different from a simple average?
- A simple average treats every value equally. A weighted average lets high-weight values pull the result more, useful when values contribute differently to the whole.
- Can I compute a GPA with this tool?
- Yes. Enter each course grade as a value and the credit hours as its weight. The weighted average equals the standard GPA calculation.