A weighted score
Values 80, 90, and 70 with weights 20, 30, and 50 give a weighted sum of 7800. Dividing by total weight 100 gives a mean of 78.
Combine values with unequal weights
Example: 80, 20 means a value of 80 with weight 20. Up to 200 rows. No header row.
Use commas, semicolons, or tabs between the two columns. Zero-weight rows have no effect. Negative weights are rejected.
Results
Weighted arithmetic mean
78
Total weight
100
Sum of value × weight
7800
| Value | Weight | Normalized weight | Value × weight |
|---|---|---|---|
| 80 | 20 | 20% | 1600 |
| 90 | 30 | 30% | 2700 |
| 70 | 50 | 50% | 3500 |
Weights are normalized automatically. Percentages can total 100, or use any nonnegative relative weights with a positive sum.
Calculations and exports run locally in your browser. Your entries are not sent to a calculation service.
How to use the Weighted Average Calculator
- 01
Enter one value and weight per line, separated by a comma, semicolon, or tab.
- 02
Use nonnegative weights; at least one weight must be greater than zero.
- 03
Check the normalized contributions and total weight. Copy or download the results table as CSV.
Examples
Frequency counts
If a value of 6 occurs twice and a value of 10 occurs three times, enter 6, 2 and 10, 3. The mean is (12 + 30) ÷ 5 = 8.4.
Relative rather than percentage weights
Weights 2, 3, and 5 produce the same weighted mean as 20, 30, and 50. Only their relative sizes matter.
How the denominator works
The weighted arithmetic mean is the sum of each value multiplied by its weight, divided by the sum of all weights. Normalization means weights do not have to total one or 100. The contributions table shows what fraction of total weight belongs to each row.
Choose weights for the quantity
Weights should reflect what the average represents, such as observation counts or assessment shares. Averaging rates may require a different denominator: equal-distance travel segments are not generally combined by taking an arithmetic mean of their speeds. Decide the measurement model before entering numbers.
Zero-weight rows stay visible
A row with weight zero has no numerical effect but remains in the output for inspection. Negative weights are rejected because this tool is designed for ordinary nonnegative weighting. All decimal arithmetic is performed with exact fractions before formatting.
What to know
- Up to 200 value–weight rows and 100,000 characters.
- This is an arithmetic weighted mean, not a harmonic or geometric mean. Displays truncate long decimals.
Common questions
Do weights have to total 100?
No. The sum is used as the denominator. If you intend percentages to total 100, check the displayed total yourself; the calculator does not assume that intent.
Can values be negative?
Yes. A negative observation can be combined with nonnegative weights. The weighted mean remains between the minimum and maximum positively weighted observations.
Can I paste a spreadsheet?
Yes, for two columns without a header. Tabs between a value and weight are accepted. Each row must contain exactly two numeric cells.