Weighted Average Calculator
Enter each value with its weight to get the weighted average, the total weight and what every row contributes, so you can see why it differs from a simple average.
Last updated November 3, 2026
Result
Weighted average = 83.333333
Total weight: 6. Simple average of the values: 80.
| Value | Weight | Share | Weight x value |
|---|---|---|---|
| 90 | 3 | 50% | 270 |
| 80 | 2 | 33.333333% | 160 |
| 70 | 1 | 16.666667% | 70 |
Show the work
Formula: weighted average = sum(weight x value) / sum(weights)
- Multiply each value by its weight: 3 x 90 = 270; 2 x 80 = 160; 1 x 70 = 70.
- Sum of weight x value = 500.
- Sum of weights = 6.
- Weighted average = 500 / 6 = 83.333333.
Result: 83.333333
How a weighted average is calculated
weighted average = sum(weight × value) ÷ sum(weights)
A weighted average is an average where some values count for more than others. Multiply each value by its weight, add up those products, and divide by the sum of the weights. A value with a large weight pulls the result toward itself, and a value with a small weight barely moves it.
The weights can be anything that says how much a value counts: percentages, credit hours, number of shares, how many times a value occurred, or just 1, 2 and 3. Only the ratio between weights matters, so weights of 2 and 3 give the same answer as weights of 40 and 60.
The calculator lists each row’s share of the total weight and its weight × value product, then compares the result with the simple average of the values. If all weights are equal, the two averages match.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Also useful alongside this calculator: Weighted Grade Calculator, GPA Calculator and Z-Score Calculator.
Weights do not need to add up to 100
Because the formula divides by the total weight, the weights can sum to any positive number. Scores of 70 and 90 with weights 40 and 60 give (2,800 + 5,400) ÷ 100 = 82. Weights of 2 and 3 give (140 + 270) ÷ 5 = 82 as well.
The weights must not be negative, and they cannot all be 0, because the total weight would be 0 and the division would be undefined. A row with weight 0 is allowed and simply counts for nothing.
Weighted versus simple average
A simple average treats every value the same. For 90, 80 and 70 it is 80. If the 90 counts three times and the 70 once, the weighted average rises to 83.333333, because the largest value now has the largest say.
Use the Average Calculator when every number counts equally. Use this page when the numbers represent groups of different size, such as batches, categories or credit hours.
Common uses
Grade point average weights each grade by its credit hours. A 4.0 in a 3-credit course, a 3.0 in a 4-credit course and a 3.7 in a 2-credit course give (12 + 12 + 7.4) ÷ 9 = 3.488889. For graded categories with percentage weights, the Weighted Grade Calculator adds a target mode.
Investors use it for the average price paid. Buying 10 shares at 50, 20 at 40 and 30 at 35 costs 500 + 800 + 1,050 = 2,350 for 60 shares, an average of 39.166667 per share. Treat it as arithmetic only, not financial advice.
Averages from a frequency table
When a value appears several times, its count works as the weight. The values 1, 2 and 3 occurring 5, 3 and 2 times give (5 + 6 + 6) ÷ 10 = 1.7. This is the same as writing all ten numbers out and taking their mean.
How to use the Weighted Average Calculator
- Enter the first value and its weight in the first row.
- Use Add row for each further value; rows left completely blank are ignored.
- Read the weighted average, the total weight and the share of each row.
- Open Show the work to see the products, then use Copy, Print or Share.
Worked example
Take the values 90, 80 and 70 with weights 3, 2 and 1. The products are 270, 160 and 70, which sum to 500. The total weight is 6, so the weighted average is 500 ÷ 6 = 83.333333, while the simple average is 80.
| Value | Weight | Share of weight | Weight × value |
|---|---|---|---|
| 90 | 3 | 50% | 270 |
| 80 | 2 | 33.33% | 160 |
| 70 | 1 | 16.67% | 70 |
| Total | 6 | 100% | 500 |
Frequently asked questions
What is a weighted average?
It is an average in which each value is multiplied by a weight that says how much it counts, then the sum of those products is divided by the sum of the weights.
Do the weights have to add up to 100?
No. Any positive total works because the calculator divides by the total weight you enter. Only the ratio between the weights affects the answer.
Can a weight be zero or negative?
A weight of 0 is allowed and means the value is ignored. A negative weight is rejected, and so is a set of weights that adds up to 0.
When is the weighted average the same as the simple average?
When every weight is equal. It also matches when the larger weights fall on values close to the simple average, but in general the two differ.
Are my numbers stored or sent anywhere?
No. The calculation runs in your browser and nothing you enter is saved or uploaded unless you copy or share a link yourself.