Weighted Average Calculator
Calculate a weighted average from a list of value and weight pairs.
Value / Weight Pairs
#1
#2
#3
Weighted Average
76.6667
Total weight: 6How to Calculate a Weighted Average
A weighted average multiplies each value by its assigned weight before averaging, so values with a larger weight count for more in the final result than values with a smaller weight. Add each value/weight pair below and the total weighted average updates automatically.
Example
Three values — 80 with weight 2, 90 with weight 1, and 70 with weight 3 — give a weighted average of (80×2 + 90×1 + 70×3) ÷ (2+1+3) = 460 ÷ 6 ≈ 76.67, which differs from the plain average of the three values (80) because the lower value (70) carries more weight.
Common Use Cases
- Calculating the average purchase price of a stock or asset bought in multiple lots.
- Combining survey or review scores where some responses carry more weight than others.
- Blending interest rates across loans or accounts of different sizes.
FAQs
What's the difference between a weighted average and a simple average?
A simple average treats every value equally, dividing the sum of values by the count of values. A weighted average instead gives each value an explicit importance (its weight), so values with larger weights pull the result toward themselves more strongly.
Do the weights need to add up to 100 or 1?
No — the formula divides by the total weight you enter, so it works correctly whether your weights are percentages, counts, dollar amounts, or any other consistent unit, regardless of what they sum to.
What happens if a weight is zero?
A row with a weight of zero is effectively excluded from the result, since it contributes nothing to either the weighted sum or the total weight. Negative weights aren't meaningful for a typical weighted average and should be avoided.