What Is the Mean (Average)?
The arithmetic mean, commonly called the average, is the most widely used measure of central tendency. It tells you the "typical" value in a data set by balancing all the numbers around a single point. You find it by adding up every value and dividing the total by how many values there are. This calculator does that work for you and also reports the sum and the count so you can see exactly how the result was produced.
How to Use This Calculator
Type or paste your numbers into the box. You can separate them however you like — with commas, spaces, tabs, or one number per line — and you can even mix these styles freely. Empty entries and stray separators (like a trailing comma) are ignored, so a messy paste still works. Decimals and negative numbers are fully supported. Press calculate to see the average, the count of values, and their sum.
The Formula Explained
The mean is written as \(\bar{x}\) (read "x-bar"). The formula is $$\bar{x} = \frac{\sum x_i}{n},$$ where \(\sum x_i\) is the sum of all the values and \(n\) is the number of values. In plain words: total everything up, then divide by how many things you totaled. If there are no numbers (\(n = 0\)) the average is undefined, so the calculator asks you to enter at least one value instead of dividing by zero.
Worked Example
Suppose your data is 9, 10, 12, 13, 13, 13, 15, 15, 16, 16, 18, 22, 23, 24, 24, 25. There are \(n = 16\) values and their sum is 268. The mean is therefore $$\bar{x} = \frac{268}{16} = 16.75.$$ The calculator shows Average = 16.75, Count = 16, and Sum = 268, along with the worked line "Average = Sum / Count = 268 / 16 = 16.75".
FAQ
What's the difference between mean and median? The mean averages all values and is sensitive to outliers, while the median is the middle value when the data is sorted and resists extreme values.
Can I include negative or decimal numbers? Yes. Negatives, decimals, and integers are all accepted and treated correctly in the sum and average.
What happens to non-numeric text? Tokens that are not valid numbers are simply skipped so they do not affect the result.
