Arithmetic mean calculator
Enter as many values as you like and the calculator works out their arithmetic mean along with the total and the count. Add or remove rows at any point.
The arithmetic mean of 3 numbers is 18.00.
Formula
x₁ … xₙ are the numbers and n is how many there are. Add every value and divide by the count.
How we got there
The mean need not be one of the data values — the mean of 12, 18 and 24 is 18, but the mean of 1 and 2 is 1.5.
How to work out an arithmetic mean by hand
- Add all the numbers
12 + 18 + 24 = 54. The order you add them in makes no difference.
- Count how many numbers there are
Three in this example. That becomes the denominator.
- Divide the total by the count
54 ÷ 3 = 18. That is the arithmetic mean of the set.
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Frequently asked questions
Add all the numbers and divide the total by how many there are. For 12, 18 and 24: 54 ÷ 3 = 18.
No. The mean of 1 and 2 is 1.5, which is not in the set at all.
Because every number enters the total with the same weight. In those cases the median describes the set better.
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