Weighted Average Calculator
Some numbers count more than others. Enter each value with its weight and get the weighted average, with the working shown.
- Runs in your browser
- Any weights: %, credits, hours
- Shows the working
- Free
Weighted average
Weights don't have to add up to 100. We divide by the total weight.
Show the working
How a weighted average works
Multiply
Multiply each value by its weight. Scores 92, 85, 78 with weights 30, 30, 40 give 2760, 2550 and 3120.
Add both columns
Add the products: 8430. Add the weights: 100.
Divide
8430 ÷ 100 = 84.3. If the weights had added to 50 instead, you would divide by 50, so they never need to total 100.
Where weighted averages show up
Grades
Homework 20%, midterm 30%, final 50%. Each score is weighted by its share. Grade average calculator →
GPA
Each course grade is weighted by its credit hours. A 4-credit A counts more than a 1-credit A.
Money
Average purchase price of shares bought in several lots, or a portfolio return weighted by how much is in each holding.
Questions people ask
How do you calculate a weighted average?
Multiply each value by its weight, add up all those products, then divide by the sum of the weights. For values 92, 85, 78 with weights 30, 30, 40: (92×30 + 85×30 + 78×40) ÷ (30 + 30 + 40) = 8430 ÷ 100 = 84.3.
Do the weights have to add up to 100?
No. The calculator divides by the total of the weights, so 30/30/40, 3/3/4 or 0.3/0.3/0.4 all give the same answer.
What is the difference between a weighted average and a normal average?
A normal average treats every value equally. A weighted average lets some values count more, according to their weight. If all weights are equal, both give the same result.
Can a weight be zero?
Yes. A zero weight means that value is ignored. If every weight is zero there is nothing to divide by, so there is no result.
How do I average percentages?
If each percentage came from a different-sized group, weight each one by its group size. Averaging 50% of 10 people and 100% of 90 people gives 95%, not 75%.