Syntax
STDEV(value1, [value2, ...])
| Parameter | Description |
|---|---|
| value1 | Parameter of the STDEV function. |
| [value2 | (Optional.) Parameter of the STDEV function. |
| ...] | Parameter of the STDEV function. |
Examples
Sales variability
Formula
=STDEV(B2:B13)
Returns the standard deviation of 12 months of sales. A high value means revenue swings widely; a low value means consistent sales.
Quality control spread
Formula
=STDEV(D2:D500)
Measures how much product weights vary from the average. If the mean is 100g and STDEV is 2g, most products weigh between 98g and 102g.
Comparing consistency
Formula
=STDEV(A2:A50) < STDEV(B2:B50)
Returns TRUE if column A's values are more consistent (less spread) than column B's.
Common Errors
#DIV/0!
Returned when fewer than 2 numeric values are provided. Standard deviation of a sample requires at least 2 data points.
#VALUE!
Occurs when non-numeric arguments are passed directly.
Tips
Sample vs. population
STDEV divides by n-1 (sample). If your data IS the entire population (not a sample), use STDEV.P which divides by n.
68-95-99.7 rule
For normally distributed data, about 68% of values fall within 1 STDEV of the mean, 95% within 2, and 99.7% within 3.
Text and blanks are ignored
STDEV skips text and blank cells. If you want text treated as 0, use STDEVA instead.
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