How to calculate the average
The ordinary (arithmetic) average, or mean, takes two steps:
- Add up all the numbers.
- Divide by how many numbers there are.
mean = sum of the numbers / count of the numbers
Example: the numbers 12, 15, 9, 21, 15 and 18 add up to 90. There are 6 of them, so the mean is 90 / 6 = 15.
Separate numbers with commas, spaces or new lines, and don't use thousands separators: write 1500, not 1,500. You can also copy a column from Excel or Google Sheets and paste it straight in.
Mean, median and mode
The mean is not the only way to describe the "middle" of a list. There are three common measures of central tendency:
- Mean: the sum divided by the count. Sensitive to outliers.
- Median: the middle value when the numbers are sorted from low to high. With an even count it is the average of the two middle values. For 9, 12, 15, 15, 18, 21 the median is (15 + 15) / 2 = 15.
- Mode: the value that occurs most often. In the example 15 appears twice, so the mode is 15. There can be several modes, or none if every value appears once.
When to use the median
With outliers, the median often gives a fairer picture. Take five monthly salaries: $1,800, $2,100, $2,300, $2,500 and $9,500. The mean is $3,640, yet four of the five people earn less. The median is $2,300 and says more about a "typical" salary. That is why statistics offices often report household income and house prices as medians.
Spread
Two lists can have the same mean but be distributed very differently. That is why the calculator also shows:
- the minimum and maximum and the range (maximum minus minimum);
- the standard deviation, both for a sample and for the entire population. For an explanation and a step-by-step table, see the standard deviation calculator.
Weighted average
If some values count more than others, such as course grades with different weights, you need a weighted average. Use the grade calculator: enter a weight for each grade and see what you need on your next test.
Averages in Excel
In Excel and Google Sheets use =AVERAGE(A1:A10), =MEDIAN(A1:A10) and =MODE(A1:A10). Empty cells are skipped, but cells containing 0 are counted. Keep that in mind when you average a column with values that haven't been filled in yet.
Other kinds of averages
Besides the arithmetic mean there are specialised averages. The geometric mean is used for growth rates and investment returns, and the harmonic mean for averaging speeds over equal distances. If you drive 60 km at 30 km/h and 60 km back at 60 km/h, your average speed is 40 km/h, not 45.
Everyday uses
Averages are everywhere: your grade point average, the average price of groceries, average monthly spending, a batting average or the average temperature in a month. When you compare averages, always check how many values are behind them, because an average of three numbers is far less reliable than an average of three hundred.
Frequently asked questions
How do you calculate the average?
Add all the numbers and divide by how many there are. The average of 4, 6 and 8 is (4 + 6 + 8) / 3 = 6.
What is the difference between mean and median?
The mean is the sum divided by the count; the median is the middle value. With outliers they can differ a lot.
What is the mode?
The value that occurs most often. If every value appears once, there is no mode.
How do I enter decimals?
Use a decimal point (7.5) and separate numbers with commas, spaces or new lines. Don't use thousands separators.
How many numbers can I enter?
Up to 10,000 numbers. You can paste an entire column from a spreadsheet.
Does a 0 count in the average?
Yes, 0 is an ordinary value. Leave out numbers you don't want to include.
Last reviewed: 2026-10-06. Results are estimates for information only.