Mean, Median, Mode Calculator
Enter a set of numbers to find the mean, median, and mode with explanations of which measure is most appropriate for your data.
How Mean, Median, and Mode Are Calculated
These three measures of central tendency describe the “center” of a data set, each in a different way.
Mean (Average):
Mean = Sum of all values / Count of values
Median (Middle Value): Sort values in order. If count is odd, take the middle value. If even, average the two middle values.
Mode (Most Frequent): The value that appears most often. A dataset can have no mode, one mode, or multiple modes.
Worked Example: Data set: 4, 7, 7, 9, 13, 15, 15, 15, 21
- Mean = (4+7+7+9+13+15+15+15+21) / 9 = 106 / 9 = 11.78
- Median = middle value (5th of 9) = 13
- Mode = 15 (appears 3 times)
When to Use Each:
- Mean: Symmetric distributions without outliers — exam scores, heights, temperatures
- Median: Skewed data or data with outliers — income, house prices, response times
- Mode: Categorical data or finding most common occurrence — shoe size, favorite color
Outlier Effect Example: Salaries: $30k, $32k, $35k, $31k, $500k
- Mean = $125.6k — misleading (skewed by CEO salary)
- Median = $32k — better reflects typical employee
- Mode = none
Standard Deviation measures spread around the mean. For this dataset: range (max−min) = 17, which gives a quick rough sense of spread.