Weighted average calculator
Find an average when values contribute different weights. Pair each value with its weight in the same list position.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Values | Separate values with commas, semicolons or new lines. Use dots for decimals. Maximum 1,000 values. |
| Weights | Separate values with commas, semicolons or new lines. Use dots for decimals. Maximum 1,000 values. |
Understanding your result
Read Weighted average, Total weight in the units and model stated on this page. The formula weighted mean = Σ(x × w) ÷ Σw defines the relationship; measurement accuracy and model applicability are separate from numerical precision.
Common mistakes
- Using a different mathematical definition or operation than the one stated by this tool.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Calculation checks, sources and review limits
What is the average when some values count more than others?
Enter values and matching weights in the same order. The result accounts for the different contribution of each value instead of treating them equally.
Common uses
- Combine scores with different weights.
- Average values across groups with different sizes.
How it works
Multiply each value by its weight, sum those products, then divide by the sum of the weights. Both lists must have the same length. Weights can be zero but cannot be negative, and their total must be positive. Relative weights need not add to 1 or 100.
Worked example
Values 80 and 90 with weights 1 and 3 give (80 × 1 + 90 × 3) ÷ 4 = 87.5.