Weighted Average Calculator
Enter each value with its weight and instantly get the weighted average — ideal for grades, GPA and investment portfolios.
What is a weighted average?
A weighted average (or weighted mean) is an average in which each value contributes according to how important it is, expressed as its weight. Instead of treating every number equally — as a simple average does — you multiply each value by its weight, add up those products, and divide by the sum of the weights. The result is pulled towards the values that carry more weight.
Worked example: final course grade
Suppose your course mark is built from three components, each worth a different share of the final grade. List the score you got and the weight of each component:
| Component | Score | Weight | Value × Weight |
|---|---|---|---|
| Assignments | 78 | 20 | 1,560 |
| Mid-term | 85 | 30 | 2,550 |
| Final exam | 92 | 50 | 4,600 |
| Total | — | 100 | 8,710 |
Add the products: 1,560 + 2,550 + 4,600 = 8,710. Add the weights: 20 + 30 + 50 = 100. The weighted average is 8,710 ÷ 100 = 87.1. Notice this is higher than the simple average of 85, because the strong final exam carries the most weight.
Where weighted averages are used
Exams, assignments and projects each count for a different percentage of the final mark. The weighted average gives your true overall grade and is the basis of GPA and CGPA.
To find a portfolio's average return, weight each holding's return by how much money is invested in it. A large position moves the portfolio return more than a tiny one.
Weighted average cost values stock bought at different prices, and consumer price indices weight each item by how much households actually spend on it.
Frequently asked questions
What is the difference between a weighted average and a simple average?
A simple average treats every value equally — you add them up and divide by how many there are. A weighted average lets each value count by a chosen amount (its weight), so more important values influence the result more. When all weights are equal, the weighted average equals the simple average.
How do I calculate a weighted average?
Multiply each value by its weight, add up all of those products to get Σ(value × weight), then divide by the sum of the weights, Σ(weight). In formula form: Weighted Average = Σ(value × weight) ÷ Σ(weight).
Do the weights have to add up to 100 or 1?
No. Weights can be any positive numbers — percentages, credit hours, rupee amounts, or arbitrary points. Because you divide by the total of the weights, the calculator normalises them automatically, so 20/30/50 gives the same answer as 2/3/5.
Can a weight be zero or negative?
A weight of zero simply removes that value from the average. Negative weights are unusual and can produce misleading results, so this calculator is designed for zero or positive weights. If the total weight is zero, no weighted average can be calculated.
How is GPA a weighted average?
In GPA, each course grade point is weighted by the number of credit hours for that course. A 4-credit subject influences your GPA twice as much as a 2-credit subject, which is exactly a weighted average of grade points using credit hours as weights.