How to calculate Standard Deviation?

The standard deviation is a mathematical term, and symbolizes the measurement of how spread out outlaid numbers are. We are going to perform the standard deviation calculation.

Example 1 STDEV way

How to calculate the Standard Deviation using the STDEV Excel function?

Let's start by preparing your data. From this data, we will see how to calculate the Standard Deviation here.

Standard Deviation data

Click on a blank column and type in =STDEV(choose all columns with numbers in them, ex. A1:A11), and then press enter.

Standard Deviation formula

The Standard Deviation is calculated.

Standard Deviation calculated

Simple and quick. Luckily, Excel has a dedicated STDEV function for Standard Deviation calculations. There are also other Excel functions:

  • STDEV.P: Standard deviation of the population.
  • STDEV.S: Standard deviation of the sample.
  • STDEVA: Sample standard deviation, which does not ignore logical values.
  • STDEVPA: Standard deviation of the population that does not ignore logical values.

Example 2 Data Analysis way

LEt's calculate the Standard Deviation using the Data Analysis ToolPak Add-In.

First, you need to make sure your Data Analysis Toolpak Add-In is installed. Here is a lesson on how to install the Data Analysis Toolpak Add-In.

Navigate to the Data Tab on the Ribbon. Click the Data Analysis button.

Data Analysis ribbon button

A new window appears. Choose Descriptive Statistics and click OK.

standard deviation variance descriptive statistics

Enter the proper parameters:

  • Input Range: Your data range ($A$1:$A$11 in my example).
  • Labels in first row: There are no labels in my data table.
  • Output Range: Choose where you want to get your standard deviation calculated (I picked the same Sheet $F$1:$G$14).
  • Summary statistics: Make sure it is checked.

Standard Deviation Descriptive Statistics

And this is how you can see my statistics summary. The Standard Deviation is calculated in row 7. The result is the same as in Example 1, where we checked how to calculate the Standard Deviation using the STDEV Excel function.

Standard Deviation Analysis Toolpak addin calculated

Excel really helps you with statistics. Maybe now you can see that.

Further reading: 
Statistical process control chart
Calculating forecast accuracy and precision
How to calculate the variance in Excel?