Example 1
- List: 2 4 6
4
Sum 12, three numbers: 12÷3 = 4.
Arithmetic mean calculator
Type a list of numbers in one field, with spaces or commas. The arithmetic mean is the sum divided by how many items you entered. 2 4 6 gives 4. 3 4 5 4 5 gives 4.2. One outlier, like 1000 next to 10 12 11, pulls the result to 258.25.
The arithmetic mean is the sum of all numbers divided by how many there are. Every value affects the result - including a very large or very small one. If one extreme warps the picture, compare with the median.
Result
Enter a list of numbers to see the mean.
What it means
Take scores: 4, 5, 3. The sum is 12, there are 3 numbers, the mean is 12÷3 = 4. The same for any list: add everything, divide by the count. 2 4 6: sum 12, mean 4. 3 4 5 4 5: sum 21, mean 4.2.
The result does not have to be one of the typed numbers. 3 6 9 12 gives 7.5. The mean describes a typical value when the numbers are alike. When one value spikes, 10 12 11 1000 becomes 258.25; the median would sit nearer 11-12.
One Numbers field. Separate with spaces, semicolons, or commas. For a decimal use one comma or one period: 3.5. Type 2 4 6, click Calculate. The calculator also shows the sum and the count, so you can check the arithmetic.
The median sorts and takes the middle. An arithmetic series sum assumes an equal step; here there is no step. −2 0 4 8 10 has mean 4.
Without a list, nothing computes. A zero in the list counts as a value. The header does not average 2 4 6 differently.
2 5 9 11 20 gives 9.4. 10 10 10 10 50 gives 18. 1 1 2 3 100 gives 21.4. Compare those lists with the median when 100 spoils the picture.
Where it helps
- Average grades, scores, and measurements.
- A quick “how much per item”.
- Comparing groups of numbers at school and day to day.
- A starting point for more statistics (for example spread).
How to use
- Type numbers in Numbers, separated by spaces, semicolons, or commas, for example 2 4 6.
- Write a decimal with one comma or one period, for example 3.5.
- Click Calculate. 2 4 6 gives 4. 3 4 5 4 5 gives 4.2.
- Check the sum and the count next to the mean. 12÷3 = 4.
- When one outlier spoils the picture, open the median. 10 12 11 1000 here is 258.25.
Mean, sum, and median
The arithmetic mean is the sum of the numbers divided by how many you typed. 2, 4 and 6 give 4, because 12 divided by 3.
- mean
- The sum divided by the count. 3 4 5 4 5 gives 4.2. 10 10 10 10 50 gives 18, not 10.
- sum
- Every entry added together. For 2 4 6 the sum is 12. The result is it beside the mean so you can check 12÷3.
- median
- The middle after sorting, on the next card. For 10 12 11 1000 the mean is 258.25, while the median sits near 11 and 12.
Examples
Example 2
- List: 3 4 5 4 5
4.2
Sum 21, five numbers: 21÷5 = 4.2.
Example 3
- List: 10 12 11 1000
258.25
1000 pulls the mean up a lot. The median would sit near 11-12.
Example 4
- Numbers: 2 5 9 11 20
9.4
Quiz scores 2, 5, 9, 11 and 20: sum 47, mean 9.4.
Example 5
- Numbers: 1 1 2 3 100
21.4
Four small amounts and one 100: mean 21.4, because the hundred pulls the sum.
Example 6
- Numbers: 10 10 10 10 50
18
Four tens and a 50 give a mean of 18, not 10.
Example 7
- Numbers: 3 6 9 12
7.5
The list 3 6 9 12: sum 30, mean 7.5, which is not on the list.
Example 8
- Numbers: -2 0 4 8 10
4
Minus two enters the sum: −2 0 4 8 10 gives a mean of 4.
Related calculators
FAQ
What is the mean of 2 4 6?
The mean is 4. You add 2, 4 and 6 to the sum 12, then divide by three, the number of values you typed.
What is the mean of 3 4 5 4 5?
It comes out 4.2. Five numbers add to 21, and 21 divided by 5 is 4.2, the same case as on the page.
How do I separate the numbers?
Use spaces, semicolons, or commas between values. Write 3.5 with one decimal mark, or the calculator reads it as the list 3 and 5.
What is 10 12 11 1000?
The mean jumps to 258.25, because one thousand enters the sum just like eleven. The median of that four would sit between 11 and 12.
What is 3 6 9 12?
The sum 30 divided by 4 gives 7.5. The mean does not have to be one of the numbers you typed.
What is −2 0 4 8 10?
The mean is 4. Minus two lowers the sum to 20, and five numbers still split that twenty evenly.
How is the mean different from the median?
The mean feels every value, including an outlier. After sorting, the median takes the middle: for 1 1 2 3 100 the mean is 21.4 and the median is 2.
What is 10 10 10 10 50?
Four tens and a fifty give a mean of 18. The sum 90 divided by 5 does not stay at ten.
Is 2 5 9 11 20 equal to 9.4?
Yes. The quiz scores add to 47, and five numbers give 47÷5 = 9.4, exactly as on the example card.
Is this the sum 3+6+…+21 = 84?
No. That sum assumes an equal step and lives on the arithmetic-series page. Here the list can be any numbers, with no fixed step.
Knowledge sources
The calculator computes the same formula as the definition below.
Page updated in 2026.