Weighted Average Calculator
Average values that count for different amounts: grades, prices, scores.
Good to know. An exam worth 50% moves your grade five times as much as a quiz worth 10%. That’s all weighting is.
How it works
In plain words
Multiply each value by its weight, add those products up, and divide by the total of the weights. If every weight is the same, this is the ordinary average.
The formula
weighted average = (v₁ × w₁ + v₂ × w₂ + …) ÷ (w₁ + w₂ + …)
Worked example
85 × 20 + 92 × 30 + 78 × 50 = 1,700 + 2,760 + 3,900 = 8,360, and 8,360 ÷ 100 = 83.6.
Sources
No outside data or rates: this is plain arithmetic.
5 automated tests check its answers on every change.
About the weighted average calculator
A weighted average is an average where some values count more than others. The most common use is a course grade: homework worth 20%, a midterm worth 30% and a final exam worth 50%. A plain average of 85, 92 and 78 would be 85, but because the final counts for half the grade, the weighted average is 83.6.
Enter one value and its weight per line, separated by a space. The weights can be percentages, credit hours, quantities or any other numbers, and they don’t need to add up to 100: the calculator divides by whatever they add up to. Grades of 85 and 92 weighted 1 and 3 give the same answer as weights of 25 and 75.
Weighted averages are everywhere once you look. The average price you paid for shares bought in several lots is weighted by the number of shares. A GPA is grade points weighted by credit hours. A restaurant’s average rating across many reviews, or the average speed over legs of different lengths, works the same way.
The plain average is shown too, so you can see how much the weights matter. If the two are far apart, the values with large weights are pulling the result their way.
Questions people ask
How do I calculate a weighted average?
Multiply each value by its weight, add the results, and divide by the sum of the weights. For 85 (20%), 92 (30%) and 78 (50%) that is 8,360 ÷ 100 = 83.6.
Do the weights have to add up to 100?
No. The calculator divides by the total of the weights, whatever it is.
How do I work out my grade with weighted categories?
Enter your average in each category with the category’s weight. The result is your overall grade so far.