Weighted Average Calculator
Find the weighted mean of a list of values, with each product w × x, the total weight, and the division steps used on paper.
Σ(w × x) / Σw = 490 / 6
- 2 × 90 = 180.
- 3 × 80 = 240.
- 1 × 70 = 70.
- Add the products: Σ(w × x) = 490.
- Add the weights: Σw = 6.
- Divide: 490 / 6 = 81.6666666667.
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All calculations run locally in your browser. Your entered values are not sent to an external service.
How to Use the Weighted Average Calculator
Enter each value and the weight that belongs with it, then select Calculate. The tool multiplies, adds the products, adds the weights, and divides.
- Type a value and a weight on each row. Use Add Row for more pairs.
- Weights can be counts, credits, or percents. They only need to be non-negative.
- Reset restores the three-score classroom example.
The Mean, Median, Mode Calculator finds the unweighted mean. That is the special case where every weight is 1, which the Equal weights preset shows. The GPA Calculator is the same formula with letter grades turned into points on a 4.0 scale.
The Weighted-Mean Formula
Each weight stretches or shrinks that value’s pull on the average. A score of 90 with weight 2 contributes 180 to the numerator and 2 to the denominator. A score of 70 with weight 1 contributes only 70 and 1.
The weights do not have to add to 1 or to 100. Doubling every weight leaves the ratio unchanged: 4, 6, and 2 give the same average as 2, 3, and 1.
Weighted Average Examples
Three test scores
90 with weight 2, 80 with weight 3, and 70 with weight 1 give 490 / 6 = 81.6666666667. The unweighted mean is 80, because the 90 is counted more often than the 70.
Category percents
An 85 on a 40% exam and a 90 on a 60% exam: 85 × 40 + 90 × 60 = 8800, and 40 + 60 = 100, so the course average is 88.
Equal weights
4, 8, 15, 16, 23, 42 with weight 1 each is 108 / 6 = 18, the same mean as on the Mean, Median, Mode Calculator.
A single pair
One value 10 with weight 5 is 50 / 5 = 10. A weighted average of one number is that number.
All weights zero
If every weight is 0, the denominator is 0 and the average is undefined. The Zero weights preset shows that error.
When Weights Matter
Use a weighted average when the numbers are not equally important: exam categories, repeated measurements, population sizes, or credit hours. Use the ordinary mean when each observation should count once.
This page does not convert letter grades, compute a weighted standard deviation, or forecast a final exam score. For letter grades and credits, use the GPA Calculator.
Common Weighted-Average Mistakes
Averaging the values and ignoring the weights
90, 80, and 70 average to 80. With weights 2, 3, and 1 the answer is 81.67. The unweighted mean is shown so you can see the difference.
Forcing the weights to add to 100
Percents that already add to 100 are fine, but 2, 3, and 1 work the same way. Only the ratio of the weights matters.
Averaging group averages without the group sizes
If one class of 30 averages 70 and one class of 10 averages 90, the combined mean is not 80. Use 70 with weight 30 and 90 with weight 10: 3000 / 40 = 75.
Using a negative weight
A negative weight is not a standard classroom weighted mean. Enter zero or a positive weight, or drop the row.
Treating this as a GPA tool
GPA still needs the letter-to-points table. This page wants the numeric values already in hand.
Weighted Average FAQs
How do you calculate a weighted average?
Multiply each value by its weight, add those products, and divide by the sum of the weights.
What is the weighted average of 90, 80, and 70 with weights 2, 3, and 1?
81.6666666667, because 490 ÷ 6.
Do the weights have to add to 100?
No. Any positive total works. Percents that add to 100 are just one convenient choice.
When is the weighted average the same as the mean?
When every weight is equal. The Equal weights preset matches the Mean, Median, Mode Calculator.
Is GPA a weighted average?
Yes. Credits are the weights and grade points are the values. Use the GPA Calculator when you have letter grades.
Are my numbers sent to a server?
No. The calculation runs locally in your browser.
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Reviewed by Prof. Dr. Khalil Mudassar (PhD) · Last updated: [mc_modified_date]
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Disclaimer
This calculator is for general educational use. It computes an unnormalized weighted mean of numeric values. It is not a GPA official record, a survey estimator, or a professional statistics package.