Excel STDEVP Function — How to Use It (with 3 Examples)

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What does STDEVP do?

STDEVP calculates standard deviation — how spread out values are from the average — assuming your data is the complete population, not a sample.

Standard deviation is just the square root of variance, so STDEVP relates to VARP exactly the way STDEV relates to VAR.

=STDEVP(number1, [number2], ...)

Argument	Description
number1 required	A number or range representing the entire population.
number2, ... optional	Additional numbers or ranges.

Example 1

Standard deviation of every employee's tenure

=STDEVP(A2:A50)

Appropriate only if A2:A50 truly is every employee, with nobody excluded.

Example 2

Compare to the sample version

=STDEV(A2:A50)

If A2:A50 is a sample, STDEV is the correct choice and will return a slightly larger number than STDEVP on the same data.

Example 3

Use inside a margin of error formula

=1.96*(STDEVP(A2:A50)/SQRT(50))

Standard deviation feeds directly into confidence interval and margin of error calculations.

⚠️ Using STDEVP for a sample

As with VARP, this is the most common mistake — most real-world data is a sample, where STDEV is correct.

Which is more commonly used, STDEV or STDEVP?

STDEV (sample) is used far more often in business contexts, since complete populations are rare outside controlled settings.

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STDEV VARP VAR