Weighted Average Calculator
Enter each value with its weight, as raw numbers (credits, quantities) or percentages, and get the weighted average with every step of the math shown.
Step-by-step
| Item | Value (x) | Weight (w) | w × x | Share of weight |
|---|
- Enter at least one value with a weight.
How to use the Weighted Average Calculator
- Choose the weight type: raw weights (credits, units, quantities) or weights in %.
- Enter each value and its weight on its own row. Press + Add row or Enter in the last row for more.
- Or paste two columns from a spreadsheet (value, weight, with an optional label first) and press Convert to rows.
- Press Calculate weighted average (results also update live) and read the result.
- Check the step-by-step breakdown and copy it if you need to show your work.
Weighted average formula
The weighted average (weighted mean) of values x₁, x₂, … with weights w₁, w₂, … is
x̄ = (w₁x₁ + w₂x₂ + … + wₙxₙ) ÷ (w₁ + w₂ + … + wₙ) = Σ(w·x) ÷ Σw
If the weights are percentages that add up to 100%, dividing by Σw is the same as converting each percentage to a decimal and adding the products.
Worked example: course grade
| Component | Score (x) | Weight (w) | w × x |
|---|---|---|---|
| Homework | 92 | 20% | 1,840 |
| Quizzes | 85 | 15% | 1,275 |
| Midterm exam | 78 | 25% | 1,950 |
| Final exam | 88 | 40% | 3,520 |
| Total | 100 | 8,585 |
Weighted average = 8,585 ÷ 100 = 85.85. The simple mean of the four scores is 85.75: the heavily weighted final exam pulls the result up slightly.
Where weighted averages are used
- Grades and GPA: scores weighted by percentage of the final mark, or grade points weighted by credit hours.
- Average purchase price: price per unit weighted by the number of units bought (for example shares or stock bought in batches).
- Surveys and ratings: average rating weighted by the number of responses at each level.
- Finance: portfolio return weighted by the amount in each investment.
Tips
- Weights only matter relative to each other: weights of 1, 2, 3 give the same result as 10, 20, 30.
- To find the score you need on a final exam, enter your other results first; the calculator shows your average over the weight completed so far.
Frequently asked questions
What is the weighted average formula?
Weighted average = Σ(w × x) ÷ Σw: multiply each value by its weight, add the products, then divide by the sum of the weights.
How do I calculate a weighted grade?
Multiply each score by its percentage weight, add them and divide by the total weight. Homework 92 (20%), quizzes 85 (15%), midterm 78 (25%) and final 88 (40%) give (1840 + 1275 + 1950 + 3520) ÷ 100 = 85.85.
What if my percentage weights don't add up to 100?
The calculator still divides by the total weight you entered. If you have only finished 60% of a course, it shows your average so far over that 60%.
What is the difference between a weighted average and a normal average?
A normal (arithmetic) mean treats every value equally. A weighted average gives more influence to values with bigger weights, such as a 4-credit course compared with a 1-credit course.
Can weights be decimals or zero?
Yes. Weights can be any non-negative numbers, including decimals. A weight of zero means the value is ignored. At least one weight must be greater than zero.
How do I calculate GPA as a weighted average?
Use each course's grade points as the value and its credit hours as the weight. For example A (4.0) in a 4-credit course and B (3.0) in a 3-credit course gives (16 + 9) ÷ 7 = 3.57.