1
Add your values
Use Add value to include every number in the set, including zero or negatives.
Math
Free tool
Average Calculator
Calculate the arithmetic mean of a set of finite numbers and see the sum and count used.
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Calculate an arithmetic average
Add as many values as you need. Negative numbers, zero and decimals are allowed.
Result
How to use this calculator
Three steps to an answer you can interpret.
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Calculate the mean
The tool sums the values and divides by how many you entered.
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Check the context
Compare the result with the inputs; extreme values can pull the mean.
Understand the result
In everyday mathematics, average often means the arithmetic mean: add all values and divide by how many values there are.
Arithmetic mean formula
Mean = Σx ÷ n, where Σx is the sum of the values and n is the number of values.
Worked example
For 10, 20 and 30, the sum is 60 and the count is 3, so the average is 20.
The sum and number of values remain visible alongside the mean.
Average vs median
The average uses every value in the sum. The median is the middle value after sorting, so the two measures answer different questions.
Effect of outliers
An unusually large or small value can pull the arithmetic mean toward it, sometimes making the median more representative of a typical observation.
Negative values
Negative numbers and zero are valid. Mixed positive and negative values are summed with their signs before division.
Common mistakes
- Dividing by the wrong count.
- Forgetting a negative sign.
- Rounding intermediate values before the final result.
More useful tools
View allFrequently asked questions
Can I enter decimals?
Yes, finite decimals are supported.
Is average always the same as median?
No. They coincide for some data sets but are different statistical measures.