Weighted average calculator
A weighted average multiplies each value by its weight, sums, and divides by the total weight.
Weighted average
82.4
- Unweighted mean
- 78
- Effect of the weighting
- 4.4
- Total weight
- 100
Show the working
- Value 1 = 85
- Weight 1 = 30
- Value 2 = 72
- Weight 2 = 20
- Value 3 = 90
- Weight 3 = 40
- Value 4 = 65
- Weight 4 = 10
- Total weight = 30 + 20 + 40 + 10 = 100
- weighted_sum = 85*30 + 72*20 + 90*40 + 65*10 = 8240
- Weighted average = 100 != 0 ? 8240 / 100 : 0 = 82.4
- Unweighted mean = (85 + 72 + 90 + 65) / 4 = 78
- Effect of the weighting = 82.4 - 78 = 4.4
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
Scenarios & local history
Compare a saved scenario
Recent calculations
The formula
- weighted mean = sum(value x weight) / sum(weight)
Set a weight to zero to leave that row out.