How to use the STDEV function

Author: Oscar Cronquist Article last updated on December 07, 2020

The STDEV function calculates the standard deviation of a group of values. The standard deviation shows how much the values differ from the mean value of the group.

Formula in cell C3:

=STDEV(B3:B14)

Excel Function Syntax

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

Arguments

number1	Required. This argument can be an array of constants or a cell reference to a group of values.
[number2]	Optional. Up to 254 additional arguments.

How to use the STDEV function

Comments

There are newer better functions that may have improved accuracy, this function is available for compatibility with earlier Excel versions.

What is Standard Deviation?

what is standard deviation

Standard deviation tells you how far from the average values are spread out. Both charts above have numbers and an average plotted, they share the same average however, the numbers are not the same.

Chart A above shows that the values are more spread out than the values in chart B. Standard deviation is used in statistics.

How is the STDEV function calculated?

The STDEV function is entered in cell D3, here is how the function calculated the output:

stdev formula

x ̅ is the average.
n is how many values.

Step 1 - Calculate the average

14 + 18 + 30 + 26 + 67 + 35 + 41 + 2 + 80 + 16 + 48 + 58 = 435

435/12 = 36.25

Step 2 - Subtract the average and square the result for all values

(14-36.25)^2 + (18-36.25)^2 + (30-36.25)^2 + (26-36.25)^2 + (67-36.25)^2 + (35-36.25)^2 + (41-36.25)^2 + (2-36.25)^2 + (80-36.25)^2 + (16-36.25)^2 + (48-36.25)^2 + (58-36.25)^2

becomes

(-22.25)^2+(-18.25)^2+(-6.25)^2+(-10.25)^2+(30.75)^2+(-1.25)^2+(4.75)^2+(-34.25)^2+(43.75)^2+(-20.25)^2+(11.75)^2+(21.75)^2

becomes

495.0625+333.0625+39.0625+105.0625+945.5625+1.5625+22.5625+1173.0625+1914.0625+410.0625+138.0625+473.0625

and returns

6050.25

Step 3 - Divide with the total count minus 1

6050.25/11 equals 550.022727272727

Step 4 - Square root the result

550.022727272727^(1/2) equals 23.4525633411942

Standard deviation based on a sample

The STDEV function estimates an output based on a sample of values, the STEDV.P however, calcualtes the standard deviation based on the entire population of values.

STDEV function formula:

stdev formula

STDEV.P function formula:

subtotal tool standard deviationP1

These formula differences explain why the functions return different values even if you use the same values.

What is the difference between the standard deviation and variance?

VAR function formula:

subtotal tool variance sample

STDEV function formula:

stdev formula

Standard deviation is the square root of the variance.

Functions in this article

STDEV

Functions in 'Compatibility' category

The STDEV function function is one of many functions in the 'Compatibility' category.

BETADIST function

Calculates the beta distribution, it represents outcomes in the form of probabilities.

BETAINV function

Calculates the inverse of the beta distribution.

BINOMDIST function

Calculates the individual term binomial distribution probability

CHIDIST function

Calculates the probability of the chi-squared distribution.

CHIINV function

Calculates the inverse probability of the chi-squared distribution.

CHITEST function

Calculates the test for independence, the value returned from the chi-squared statistical distribution and the correct degrees of freedom. Use this function to check if hypothesized results are valid.

CONFIDENCE function

Calculates the confidence interval for a population mean, using a normal distribution.

COVAR function

Calculates the covariance meaning the average of the products of deviations for each pair in two different datasets.

CRITBINOM function

Calculates the minimum value for which the binomial distribution is equal to or greater than a given threshold value.

EXPONDIST function

Calculates the exponential distribution representing an outcome in the form of probability.

FDIST function

Calculates the F probability of the right-tailed distribution for two tests.

FLOOR function

Rounds a number down, toward zero, to the nearest multiple of significance.

FORECAST function

Calculates a value based on existing x and y values using linear regression. Use this function to predict linear trends.

FTEST function

Calculates the value from an F-test. The value shows if the variances from two data sets are not significantly different.

GAMMADIST function

Calculates the gamma often used in queuing analysis (probability statistics).

LOGNORMDIST function

Calculates the cumulative lognormal distribution of argument x, based on a normally distributed ln(x) with the arguments of mean and standard_dev.

MODE function

Calculates the most frequent number in a cell range.

PERCENTRANK function

Calculates the percent rank of a given number compared to the whole data set.

QUARTILE function

Returns the quartile of a data set, use the QUARTILE function to divide data into groups.

RANK function

Calculates the rank of a specific number compared to a list of numbers.

STDEV function

Calculates the standard deviation of a group of values.

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Math and trigonometry

You will find functions in this category that calculates random values, round numerical values, create sequential numbers, trigonometry, and more.

Statistical

Calculate distributions, binomial distributions, exponential distribution, probabilities, variance, covariance, confidence interval, frequency, geometric mean, standard deviation, average, median, and other statistical metrics.

Text

Functions that let you manipulate text values, substitute strings, find string in value, extract a substring in a string, convert characters to ANSI code among other functions.

Web

Get data from the internet, extract data from an XML string and more.

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Lets you control what a user can type into a cell. It allows you to specifiy conditions and show a custom message if entered data is not valid.

Drop Down List

Lets the user work more efficiently by showing a list that the user can select a value from. This lets you control what is shown in the list and is faster than typing into a cell.

Named Ranges

Lets you name one or more cells, this makes it easier to find cells using the Name box, read and understand formulas containing names instead of cell references.

Excel Solver

The Excel Solver is a free add-in that uses objective cells, constraints based on formulas on a worksheet to perform what-if analysis and other decision problems like permutations and combinations.

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An Excel feature that lets you visualize data in a graph.

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Lets you quickly summarize vast amounts of data in a very user-friendly way. This powerful Excel feature lets you then analyze, organize and categorize important data efficiently.

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VBA stands for Visual Basic for Applications and is a computer programming language developed by Microsoft, it allows you to automate time-consuming tasks and create custom functions.

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How to use the STDEV function

Excel Function Syntax

Arguments

How to use the STDEV function

Comments

What is Standard Deviation?

How is the STDEV function calculated?

Step 1 - Calculate the average

Step 2 - Subtract the average and square the result for all values

Step 3 - Divide with the total count minus 1

Step 4 - Square root the result

Standard deviation based on a sample

What is the difference between the standard deviation and variance?

Functions in this article

Functions in 'Compatibility' category

Excel function categories

Excel categories

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