Math & Statistics
Average and Weighted Mean Calculator
Compare an ordinary mean with a weighted mean for four observations and their relative weights. The calculator uses weighted mean = Σ(value × weight) ÷ Σweights. It returns more than one result so you can check the main answer against a useful secondary measure. A weighted mean gives more influence to observations with larger weights. Weights must represent a defensible importance, frequency, probability, or exposure measure.
Check the displayed units, assumptions, and rounding before relying on the result.
Calculate and compare
Use the number box for precision or the slider for fast scenario testing.
Scenario results
Ordinary mean
78.75
Every value counts equally.
Weighted mean
83
Uses the entered relative weights.
Total weight
7
Denominator of the weighted mean.
How the calculation works
Use consistent units and retain full precision until the final display step.
Worked example
Reproduce the displayed scenario, then change one assumption at a time.
Assumptions behind the result
- • Inputs use the units shown beside each control.
- • The displayed formula is applied without hidden market or demographic data.
- • Rounding occurs only for display; calculations keep full numeric precision.
- • A weighted mean gives more influence to observations with larger weights.
- • Weights must represent a defensible importance, frequency, probability, or exposure measure.
Mistakes that change the answer
- • Mixing percentages with decimals or mixing incompatible units.
- • Relying on a rounded intermediate value instead of the full result.
- • Changing several assumptions at once instead of testing value 1 separately.