Formula
weighted average = Σ(value × weight) ÷ Σ(weight)
- value — each number being averaged
- weight — how much that number counts
Multiply each value by its weight, add them up, then divide by the total weight.
Worked example
Three weighted scores
- Value and weight on each line
- 85, 30 90, 20 70, 50
Weighted average
78.5
Total weight: 100
Sum of value × weight: 7,850
Simple (unweighted) average: 81.666667
How it works
With scores of 85, 90 and 70 weighted 30, 20 and 50, the weighted sum is 85×30 + 90×20 + 70×50 = 7,850 and the total weight is 100, so the weighted average is 78.5. The ordinary average of the same scores would be 81.67 — the heavily weighted 70 pulls the result down.
Weights can be percentages, credits, hours or any positive numbers. Only their proportions matter. For course grades with a letter grade see Weighted Marks and Grade Calculator; for a plain mean see Average Calculator.
Assumptions and limits
- Weights can't be negative, and they can't all be zero.
Related tools
Average CalculatorMean, median, mode, range, sum and count for a list of numbers.Weighted Marks and Grade CalculatorStudentOverall course percentage and letter grade from scores with different weights.CGPA CalculatorStudentCumulative GPA from semester grades, optionally weighted by each semester's credits.GPA CalculatorStudentSemester GPA from letter grades and credits on the US 4.0 scale, with cumulative GPA.Percentage CalculatorFind X% of a number, what percent one number is of another, or the whole from a part.