Weighted Average: Your Questions Answered
These are the questions people ask most often about weighted average. Each answer is short; follow the links for the full detail.
What does a weighted average calculation tell me?
Calculates averages where items count differently, like weighted exam components.
What is the formula?
Weighted mean = Σ(value × weight) ÷ Σweight.
What do I need to enter?
Values, Weights.
Can I use any units?
Yes, as long as every input uses the same unit. The answer will be in that unit (squared for areas, cubed for volumes).
Can you show an example?
For example, with these inputs:
- Values: 80, 72, 90
- Weights: 30, 30, 40
the calculator returns:
- Weighted average: 81.6
Any tips?
- Estimate the answer roughly first so you can spot a result that is clearly wrong.
- For exam work, show your method; marks are often given for working, not just the answer.
- Use brackets to make the order of operations explicit.
Background
Calculators are best used to check working rather than replace it, especially for exams where method marks count. Work the problem by hand first, then confirm with the calculator.
Each formula has assumptions built in. Area formulas assume flat shapes, volume formulas assume regular solids and statistical measures assume the data you enter is the data you want to describe. Knowing the assumptions helps you pick the right tool.
Rounding is a common source of small errors. Keep full precision during intermediate steps and round only the final answer to the number of decimal places or significant figures the question asks for.
Related calculations
- Area of a Trapezium Calculator: Calculates the area of a trapezium from the measurements you enter.
- Area of a Parallelogram Calculator: Calculates the area of a parallelogram from the measurements you enter.
- Area of an Ellipse Calculator: Calculates the area of an ellipse from the measurements you enter.
- Area of a Rhombus Calculator: Calculates the area of a rhombus from the measurements you enter.
Try it yourself with the Weighted Average Calculator.
Run your own numbers: Weighted Average Calculator