The mean and the median are both "averages", but they can tell very different stories about the same numbers. Here is when they agree, when they don't, and which one to trust.
When someone says "the average" without saying which, they almost always mean the mean.
If values are spread evenly around the middle, the mean and median land in the same place:
Here it doesn't matter which you report. The difference only shows up when the data is lopsided.
Five homes on a street sell for $210k, $225k, $240k, $260k and $1.2M.
The mean is higher than four of the five prices, because the one mansion drags it up. The median describes a typical home on that street much better. An outlier is a value far from the rest; the mean feels it, the median barely notices.
Use the median when a few values can be much larger (or smaller) than the rest:
The mean is the right choice when every value should count, and especially when you need a total:
The mode is the most common value. It's the only average that works for categories and for "which one is most popular" questions. A shoe store selling sizes 8, 9, 9, 10, 9 and 11 should stock more size 9, the mode. The mean size, 9.33, isn't a size anyone wears.
| Your data | Use |
|---|---|
| Evenly spread, no extreme values | Mean (median gives the same) |
| A few values far bigger or smaller than the rest | Median |
| You need to work out a total later | Mean |
| Some values count more than others | Weighted mean |
| Categories, or "most common" questions | Mode |
When in doubt, work out both. If they're far apart, your data has outliers, and the median is usually the more honest summary.
Try each one, then open the answer.
Compare them on your own numbers. The Average Calculator shows the mean, median, mode and range of any list side by side.