The Excel FACT function is a Math formula that returns the factorial of a given number. Factorial of a number n (denoted as n!) is the product of all numbers that are less than or equal to that number (n! = n x (n-1) x (n-2) x ... x 2 x 1).  Frequently used in probability and statistics, Excel factorial calculations are fairly simple to execute. In this guide, we’re going to show you how to use the FACT function and also go over some tips and error handling methods.

Supported versions

  • All Excel versions

Excel FACT Function Syntax




The number to be used in a factorial calculation. It must be greater than or equal to 0.


Common Use Cases

Let's take a simple combination example. Say you have 3 dishes to serve 3 people, and want to find out in how many different ways you can serve the dishes. You need to find the permutation of the dishes by using the following formula.

=FACT(3) returns 6

Other Examples

You can't calculate the factorial of a negative or a decimal number. While negative numbers will give a #NUM! error, decimal numbers will be truncated.

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Summary and Tips

  • If any of the values entered as an argument is not an integer, it will be truncated.
  • Use the FACTDOUBLE function to calculate the double factorial of a number.
  • The factorial of zero (0!) is equal to 1.


  • If any argument is a negative number, the FACT function returns a #NUM! error.