Can Excel Calculate Standard Deviation?

When analyzing a dataset, you'll often want to know how spread out your values are from the average, and that's exactly what standard deviation measures.

Contents:

1. Quick Answer

2. Which Standard Deviation Function Should You Use?

2.1 STDEV.S - For a Sample

2.2 STDEV.P - For an Entire Population

3. A Quick Example

4. What About STDEV and STDEVP?

Quick Answer

Yes, Excel can calculate standard deviation. The two main functions are STDEV.S (for a sample) and STDEV.P (for an entire population). For most everyday use, STDEV.S is the one you want.

Which Standard Deviation Function Should You Use?

Excel gives you two modern standard deviation functions, and picking the right one comes down to one question: does your data represent everyone you care about, or just a subset?

STDEV.S - For a Sample

Use STDEV.S when your data is a sample drawn from a larger population. This is the most common case. For example, if you surveyed 50 employees out of 500 to measure satisfaction scores, you'd use STDEV.S.

= STDEV.S(number1, [number2], ...)

number1 - The first value, cell, or range of cells in your dataset. You can pass up to 255 arguments.

STDEV.P - For an Entire Population

Use STDEV.P when your data contains every single member of the group you're measuring. For example, if you have the test scores for every student in one specific class and that class is the entire population you care about, use STDEV.P.

= STDEV.P(number1, [number2], ...)

The formula structure is identical to STDEV.S. The difference is in the math underneath: STDEV.S divides by n-1 (Bessel's correction), while STDEV.P divides by n. STDEV.P will always return a slightly smaller number than STDEV.S on the same dataset.

A Quick Example

Let's say you have monthly sales figures for a sales rep named John Smith in cells B2:B13, and you want to know how consistent his numbers are.

= STDEV.S(B2:B13)

That's all there is to it. Excel reads the twelve values and returns the standard deviation. A low result means John's sales are steady month to month. A high result means they're volatile.

You can also pass multiple separate ranges if your data isn't contiguous:

= STDEV.S(B2:B6, D2:D6)

STDEV ignores text, logical values, and empty cells automatically, so you don't need to clean those out first.

What About STDEV and STDEVP?

You might see the older STDEV and STDEVP functions referenced elsewhere. These are legacy functions that have been around since early versions of Excel. They still work, but Microsoft recommends using STDEV.S and STDEV.P instead since they make the sample vs. population distinction explicit in the name.

If you share workbooks with people on very old versions of Excel (pre-2010), the legacy versions are your safest bet. Otherwise, stick with the modern ones.

There are also STDEVA and STDEVPA, which work the same way but include TRUE/FALSE logical values in the calculation (TRUE = 1, FALSE = 0). Those come up rarely, but they exist if you need them.

If you're doing more advanced date-based analysis alongside your stats work, it pairs well with knowing how to calculate the number of days between two dates or how to calculate weighted averages for situations where not all data points carry equal weight.