Statistics function

Excel STDEV.P function

Q: What is the difference between STDEV.P and STDEV.S?

STDEV.P divides by n and suits a complete population. STDEV.S divides by n - 1 and suits a sample. The S result is always a little larger.

Q: Is STDEVP the same as STDEV.P?

Yes. STDEVP is the older name and returns the same result.

Q: How do I find values more than one standard deviation from the mean?

Compare each value with the mean plus or minus the standard deviation, as in the COUNTIFS example, or compute a z-score with STANDARDIZE and test ABS(z) > 1.

STDEV.P returns the standard deviation of a whole population: how far, on average, the values sit from their mean, in the units of the data. Use it when the range holds every value, such as the scores of every student in one class. For a sample, use STDEV.S.

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

Arguments

number1: The first number, cell or range.
number2: Optional. More numbers or ranges. Text, TRUE/FALSE and empty cells inside a range are skipped.

STDEV.P examples

Every result below was calculated from this sample sheet by the same spreadsheet engine the Cellwise app uses.

	A	B
1	Student	Score
2	Ava	72
3	Ben	85
4	Chloe	90
5	Dev	66
6	Ella	78
7	Finn	88
8	Gia	95
9	Hugo	74

Download this sheet as an Excel practice file (.xlsx)

=ROUND(STDEV.P(B2:B9),2)
Result: 9.39
The class averages 81, and scores typically sit about 9.39 points from that.
=ROUND(STDEV.S(B2:B9)-STDEV.P(B2:B9),2)
Result: 0.65
Treating the same scores as a sample gives a result 0.65 points higher, because STDEV.S divides by n - 1.
=COUNTIFS(B2:B9,">="&AVERAGE(B2:B9)-STDEV.P(B2:B9),B2:B9,"<="&AVERAGE(B2:B9)+STDEV.P(B2:B9))
Result: 6
Six of the eight students score within one standard deviation of the mean, between about 71.6 and 90.4. Dev and Gia are outside it.
=STDEV.P(B2)
Result: 0
A single value returns 0: one number has no spread. STDEV.S returns #DIV/0! instead.

How to use STDEV.P

Click the cell for the result.
Type =STDEV.P( and select the numbers.
Press Enter.
Round it for display with ROUND(...,2).

Common STDEV.P mistakes

Treating a sample as the population

If the scores are from a few classes out of many, they are a sample: use STDEV.S. STDEV.P is for the complete group.

Mixing in a totals row

A total or average row inside the range is counted as one more value and inflates the spread. Stop the range above it.

Blank scores typed as 0

Zeros count, empty cells do not. A missing score entered as 0 drags the mean down and the deviation up.

STDEV.P FAQ

What is the difference between STDEV.P and STDEV.S?

STDEV.P divides by n and suits a complete population. STDEV.S divides by n - 1 and suits a sample. The S result is always a little larger.

Is STDEVP the same as STDEV.P?

Yes. STDEVP is the older name and returns the same result.

How do I find values more than one standard deviation from the mean?

Compare each value with the mean plus or minus the standard deviation, as in the COUNTIFS example, or compute a z-score with STANDARDIZE and test ABS(z) > 1.

Guides that use STDEV.P

Related functions

Updated November 3, 2026