Weighted Average Calculator
Calculate a weighted average from values and weights — grades with credit hours, portfolio returns, weighted marks — and compare it to the simple mean.
About the Weighted Average Calculator
A weighted average counts some values more than others. Instead of adding everything and dividing by the count, each value is multiplied by its weight, and the total is divided by the sum of the weights: weighted average = Σ(value × weight) ÷ Σ(weights). This calculator gives you rows for values and weights — add or remove as many as you need — and shows the weighted average, total weight and the simple average for comparison.
The classic example is a GPA: your grades are the values and credit hours are the weights, so an A in a 4-credit course moves your average more than an A in a 1-credit lab. The same math powers course grades (assignments 20%, midterm 30%, final 50%), average purchase cost across multiple buys, portfolio returns, weighted survey scores and blended prices.
Weights do not need to add up to 100 or 1 — the formula normalises by the total weight automatically, so you can use percentages, credit hours, quantities or any positive numbers. Everything computes live in your browser.
How to Use the Weighted Average Calculator
- 1Enter each value in the left column and its weight in the right column.
- 2Add rows for as many value-weight pairs as you need.
- 3Read the weighted average, total weight and the simple average for comparison.
- 4Use grades with credit hours for a GPA-style calculation, or scores with percentage weights for a course grade.
Frequently Asked Questions
How do I calculate a weighted average with an example?
Multiply each value by its weight, add the products, and divide by the total weight. Scores of 85, 90 and 70 with weights 3, 2 and 1 give (85×3 + 90×2 + 70×1) ÷ 6 = 505 ÷ 6 = 84.17. The simple average of the same numbers would be 81.67 — the weighting pulls the result toward the heavier values.
How do I calculate my course grade with weighted categories?
Use the category scores as values and their percentages as weights. If assignments (20%) average 92, the midterm (30%) was 78 and the final (50%) was 85, your grade is (92×20 + 78×30 + 85×50) ÷ 100 = 84.3%. Enter the three rows and the calculator does the rest.
Do the weights have to add up to 100?
No. The formula divides by the sum of the weights, whatever it is — credit hours summing to 17, percentages summing to 100, or share quantities summing to 350 all work. Only the relative size of the weights matters.
What is the difference between weighted and simple average?
A simple average treats every value equally; a weighted average lets important values count more. They are equal only when all weights are the same. This calculator shows both side by side, so you can see exactly how much the weighting shifts the result.
How is a GPA a weighted average?
Each course grade is converted to grade points (A = 4.0, B = 3.0, ...) and weighted by credit hours. An A (4.0) in a 4-credit course and a C (2.0) in a 2-credit course give (4×4 + 2×2) ÷ 6 = 3.33 GPA — not the 3.0 a simple average would suggest. For full grade-to-point handling use our GPA calculator.