# Excel STDEV Function

## Summary

The Excel STDEV function returns an estimated standard deviation based on a sample. Standard deviation is a measure of how widely values are dispersed from the mean. The mean can be found using the AVERAGE function.

The STDEV function is currently available as a compatibility function. Microsoft has replaced STDEV with STDEV.S and recommends that you use this function for improved accuracy.

## Syntax

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

## Syntax Breakdown

Number 1
Required. The first number that corresponds to a sample of a population.

Number 2
Number 2 and subsequent number arguments are optional. The function can accept up to 255 arguments. An array or reference to an array can also be used.

## Usage Notes

STDEV returns the standard deviation from data that is representative of a sample of a population. To calculate the standard deviation for an entire population, use STDEVP or STDEV.P.

Standard deviation is used to calculate the variance in a set of numbers compared to the average, or mean, of the numbers. STDEV is intended to estimate the standard deviation for a sample, not the entire population.

Standard deviation is calculated using the "n - 1" method.

Logical values and text representations of numbers that are entered directly into an argument are counted. The function ignores logical values, text representation of numbers, error values, and empty cells that are contained in an array or reference.

Use the STDEVA function to calculate logical values and text representation of numbers.

Variations of Standard Deviation Functions in Excel
Function Data Set Text & Logical Values
STDEV Sample Ignored
STDEVP Population Ignored
STDEV.S Sample Ignored
STDEV.P Population Ignored
STDEVA Sample Evaluated
STDEVPA Population Evaluated