Weighted Average Calculator
Find the weighted average of values that count for different amounts, such as test marks worth different shares of a final grade.
One per line: the value, a space, then its weight (e.g. marks and the percentage each part counts).
Weighted average
84.9
- Simple average, for comparison
- 82.3333
- Total weight
- 100
The weighted average is 84.9, against a simple average of 82.3333.
How it's worked out
- Multiply each value by its weight
85 × 30 + 72 × 20 + 90 × 508,490 - Divide by the total weight
8,490 ÷ 10084.9
The formula
Weighted average = Σ (value × weight) ÷ Σ weights
Worked example
Marks of 85, 72 and 90 counting 30%, 20% and 50%: (85 × 30 + 72 × 20 + 90 × 50) ÷ 100 = 8,490 ÷ 100 = 84.9. The simple average would be 82.33.
Questions people ask
How do I calculate a weighted average?
Multiply each value by its weight, add the results, and divide by the total of the weights.
How is it different from a normal average?
A normal average counts every value equally. A weighted average lets bigger weights count more: a final exam worth 50% moves the result more than a quiz worth 20%.
Do the weights have to add up to 100?
No. Any weights work, because the total is divided out at the end.
About this calculator
Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem