STDEV function in Excel calculates the sample standard deviation of a supplied set of values. Standard Deviation, measures the deviation of number from the average value.
Standard Deviation is calculated using formula

Sample Standard Deviation is calculated using formula
Where,
- X takes each value in the set;
- X̄ is the average of the set of values;
- N is the number of values.
Syntax of STDEV Function in Excel:
STDEV (number1, [number2], … )
Where the number arguments are numeric values for which you want to calculate the sample standard deviation.
Example of STDEV Function in Excel
The Above example calculates the sample standard deviation of subject scores with formula
= STDEV (A2:A13)
Which results in value 13.36776