This average percentage calculator averages up to ten percentages, optionally weighting each one by its sample size.
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Average Percentage Calculator
Average percentages, optionally weighted by sample size.
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About this calculator
Formula notes
Simple average = Σx ÷ n; with sample sizes, weighted average = Σ(xᵢ × nᵢ) ÷ Σnᵢ.
Worked examples
- Example: 80% from 1 sample and 100% from 3 samples weight to (80×1 + 100×3) / 4 = 95%.
- 80% from 1 sample and 100% from 3 samples weight to (80×1 + 100×3) / 4 = 95%.
How to use it
- Enter each percentage and, if applicable, its sample size.
- Choose how many entries to include.
- Read the simple or sample-size-weighted average.
Frequently asked questions
When should I weight by sample size?
When the percentages come from groups of different sizes: a 90% from 10 people should count ten times as much as a 90% from one person.
Why is the weighted result different from the simple average?
Weighting gives larger groups more influence; the simple average treats every percentage as equally important regardless of group size.
Limits and interpretation
- The weighted average is meaningful only when each percentage is paired with the group size it came from; mismatched pairs produce misleading results.
- Percentages from overlapping or non-independent groups cannot be combined correctly by any weighting scheme.