The mean adds everything up and divides by the count; the median is the middle value once the data is sorted; the mode is the value that appears most often. Use the mean for roughly symmetric data without extreme values, the median when outliers or skew are present (incomes, prices, response times), and the mode for categories or the most common value.
At a glance
| Mean | Median | Mode | |
|---|---|---|---|
| Definition | Sum ÷ count | Middle of the sorted list | Most frequent value |
| Affected by outliers | Strongly | Barely | No |
| Works for categories | No | No | Yes |
| Always exists | Yes | Yes | Not always unique |
| Best for | Symmetric data | Skewed data | Most common choice |
A worked example
Eight salaries: 32,000, 35,000, 35,000, 38,000, 41,000, 45,000, 52,000, 250,000.
| Measure | Value | How |
|---|---|---|
| Mean | 66,000 | Sum 528,000 ÷ 8 |
| Median | 39,500 | Average of the 4th and 5th values (38,000 and 41,000) |
| Mode | 35,000 | Appears twice |
| Range | 218,000 | 250,000 − 32,000 |
One very large salary pulls the mean far above what almost everyone earns. Without it, the mean of the other seven is 39,714 and the median is 38,000. The median barely moved (39,500 to 38,000) while the mean dropped by 26,286.
Use the Mean, Median, Mode & Range Calculator to compute all four at once, the Average Calculator for quick means, and the Statistics Calculator for spread and standard deviation.
Which should you choose?
- Typical value in skewed data: median.
- Total divided fairly among items: mean.
- Most common category or size: mode.
- Reporting honestly: show the mean and median together; a big gap signals skew.
For how spread is measured, see How Standard Deviation Works; for definitions, Mean, median and mode and Median.