Skewness Calculator

This skewness calculator works out the moment coefficient of skewness for any data set you enter, showing how asymmetric your numbers are around their average. Type in a list of values separated by commas, for example test scores, wait times or income figures, and the calculator instantly returns three results: the skewness value, the mean of your data, and the sample size, the count of numbers entered. A skewness of zero means your data is symmetric, spread evenly either side of the mean, much like the normal distribution. A positive value shows a long tail stretching to the right, where a few unusually large values pull the mean upward, while a negative value shows the opposite, a long tail to the left dragging the mean down. This matters because skewed data can make the mean misleading as a typical figure, in which case the median often describes the centre more fairly. The calculator uses the population standard deviation in its formula, the average of each value's deviation from the mean cubed, divided by the standard deviation cubed, then rounds results for easy reading. Below the calculator you will find the formula explained, a worked example using a symmetric data set to confirm a skewness of zero, and answers to common questions about interpreting positive, negative and zero skew for statistics assignments, research or everyday data analysis.

Data set, comma separated

Skewness = 0

Mean6

Sample size5

The formula

The moment coefficient of skewness is the third standardised moment: the average of (x minus the mean) cubed, divided by the standard deviation cubed (using the population standard deviation). Positive means right-skewed, negative left-skewed, zero symmetric.

Worked example

The symmetric set 2, 4, 6, 8, 10 has mean 6 and a skewness of 0, because the values balance evenly either side of the mean. Enter that set to confirm, then try an asymmetric one.

Frequently asked questions

What does skewness measure?

The asymmetry of a distribution. Positive skew has a long right tail, negative skew a long left tail.

What does zero skewness mean?

A symmetric distribution, where values are balanced either side of the mean, like the normal distribution.

Why does skewness matter?

It tells you whether the mean is pulled by a tail, and whether the median might describe the centre better.

Who this calculator is for

This calculator is for statistics students, researchers and analysts.

What this calculator assumes

You enter valid numbers.
The standard formula is applied.
Results are rounded for display.

Formula and sources

Related calculators

Standard Deviation Calculator: spread of data.
Z-Score Calculator: standard score.
Mean Median Mode Calculator: averages.

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