Excel STDEV.S Function (Sample Spread) – Examples & Practice
Practice the Excel STDEV.S function online with an interactive grid, instant feedback, and clear formula help.
Instruction
Calculate sample standard deviation for values in B2:B6.
Formula Syntax
=STDEV.S(number1, [number2], ...)
- number1: First number or range in the sample.
- [number2], ...: Optional additional numbers or ranges.
What it does
STDEV.S estimates the standard deviation of a population based on a sample. It uses the unbiased sample estimator commonly taught in statistics courses.
Excel STDEV.S Function Examples
Sample of customer spend
=STDEV.S(B2:B50)
Estimates spread when B2:B50 is a sample from a larger customer base.
Two sample columns combined
=STDEV.S(B2:B20, D2:D20)
Only valid if treating the union as one combined sample is statistically appropriate.
Classroom quiz variability
=STDEV.S(C2:C31)
Shows how widely scores vary week to week.
statistics-sample.xlsx
| A | B | |
|---|---|---|
| 1 | Sample | Value |
| 2 | S1 | 12 |
| 3 | S2 | 15 |
| 4 | S3 | 15 |
| 5 | S4 | 18 |
| 6 | S5 | 21 |
| 7 | Output |
Input Formula
Need Help?
Tips
- Plot histograms or box plots alongside SD for context.
- Align with **AVERAGE** for reporting mean ± spread narratives.
- Document sample selection criteria.
STDEV.S Function Use Cases
- Survey samples and A/B test metrics
- Manufacturing samples when full population is not measured
- Risk reporting on historical return samples
- Teaching inferential thinking in spreadsheets
- Pair with confidence-interval discussions outside Excel
Common mistakes - STDEV.S function not working
- Using STDEV.S when you truly have the entire population (use STDEV.P)
- Mixing units (dollars with counts)
- Including a text header row inside the range
- Confusing SD with standard error of the mean
- Tiny n with over-interpretation
FAQ
STDEV.S vs STDEV.P?
STDEV.S uses the sample formula (divide by n−1). STDEV.P uses the population formula (divide by n) when data are the full population.
Is STDEV.S the same as old STDEV?
In modern Excel, STDEV.S is the recommended name for the sample standard deviation.
How small can n be?
With fewer than two numeric points, Excel cannot compute a sample SD and returns an error.
Does STDEV.S ignore text?
Text should be avoided in the numeric range; blanks are typically ignored.
Should I remove outliers first?
That is an analytical choice—document whether outliers are errors or real variability.
Comparison
| Function | Use case |
|---|---|
| STDEV.S | Random sample |
| STDEV.P | Full population |
| VAR.S | Sample variance |
Example
=STDEV.S(B2:B6)=STDEV.P(B2:B6)
Advanced examples
Sample CV
=STDEV.S(B2:B50)/AVERAGE(B2:B50) for relative dispersion when the mean is meaningful.
Filter then STDEV.S
=STDEV.S(FILTER(B2:B100, A2:A100="North")) on dynamic Excel when you need SD for one segment.