Weighted Average Calculator
When some values count for more than others.
When some values count for more than others. A weighted average lets some values count for more.
Optional.
Optional.
Weighted mean
87
Arithmetic mean is 85
A weighted mean lets some values count for more. It is the ordinary mean when every weight is equal, and the difference from 85 here is entirely down to the weighting — which is exactly how course grades, index funds and survey results are built.
How the Weighted Average Calculator works
A weighted average lets some values count for more. It reduces to the ordinary mean when every weight is equal, so any difference between the two is entirely down to the weighting, which is exactly how course grades, index funds and survey results are built.
Also known as: weighted mean calculator · how to calculate weighted average · weighted grade average · weighted average formula
Where to go next
The Weighted Average question rarely arrives on its own. These are the ones that usually come with it:
- Average Calculator — Mean, median, mode, range, and standard deviation.
- Harmonic Mean Calculator — The right average for speeds and rates.
- Final Grade Calculator — The score you need on the final, and whether it is reachable.
- Percentage Calculator — Every common percentage question in one place.
Frequently asked questions
How do I calculate a weighted average?
Multiply each value by its weight, add those products, and divide by the total weight. An 80 at 30% and a 90 at 70% average to 87, not 85.
Do the weights need to add to 100?
No. They are normalised by their own total, so 3 and 7 work exactly the same as 30% and 70%.
When is a weighted average the wrong tool?
When the quantities are rates over a fixed distance or time — average speed, for instance — where the harmonic mean is correct instead.
Why is my weighted average different from the simple one?
Because the weights are pulling it toward the more heavily weighted values. If they were equal the two would agree exactly.
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Related calculators
Average Calculator
Mean, median, mode, range, and standard deviation.
OpenHarmonic Mean Calculator
The right average for speeds and rates.
OpenFinal Grade Calculator
The score you need on the final, and whether it is reachable.
OpenPercentage Calculator
Every common percentage question in one place.
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