Example
For 12, 15, 19, 20, 24, the sum is 90 and the count is 5, so the arithmetic average is 18. Because the median is 19, the mean and median tell a similar story for this balanced dataset.
What kind of average this calculator uses
The main result is the arithmetic mean: add the values and divide by the count. For 12, 15, 19, 20, 24, the sum is 90 and the count is 5, so the average is 18.
Why median and range are shown too
The mean can look reasonable even when the dataset is skewed. Showing median and range beside the mean helps you see whether one extreme value is pulling the average away from the typical value.
How to interpret the result
A mean is most useful when all values measure the same thing over the same time period and extreme values are meaningful rather than data-entry errors. If the mean and median are far apart, inspect the values before relying on one summary number.
Common mistakes
- Dropping zeros even when zero is a real value.
- Combining values from different units, currencies or time periods.
- Using mean for skewed data without checking median.
- Rounding every input before calculating instead of rounding the final result.
When another measure fits better
Use median for skewed data, mode for the most common category or value, and standard deviation when spread is important. A single average can hide the shape of the data.
Last reviewed: 2026-05-17