Excel FACT Function

The Excel FACT function returns the factorial of a given number. In mathematics, the factorial of a non-negative integer n is the product of all positive integers less than or equal to n, represented with the syntax n!

FACT takes just one argument, number, which should be a positive integer. If number is not an integer, the decimal portion of number will be removed before the factorial is calculated.

Examples

=FACT(3) // returns 6
=FACT(4) // returns 24
=FACT(5) // returns 120

If number is not an integer it will be truncated to an integer:

=FACT(3.2) // returns 6

When number is zero, FACT returns 1:

=FACT(0) // returns 1

If number is negative, FACT returns the #NUM! error:

=FACT(-3) // returns  #NUM!

Notes

• Number cannot be negative or FACT will return the #NUM error.
• If number is not an integer it will be truncated to an integer, then solved.