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FACT Function
Summary
The Excel FACT function calculates the factorial of a nonnegative integer, returning the product of all positive integers from 1 up to the specified number. Essential for permutation calculations and combinatorial analysis.
Syntax
FACT(number)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| number | Number |
Yes | The nonnegative integer for which to calculate the factorial. Truncated if not an integer. |
Using the FACT Function
Use FACT for mathematical calculations involving permutations, combinations, and probability where factorial values are needed. Perfect for counting arrangements of distinct objects.
Common FACT Examples
Basic Factorial Calculation
=FACT(5)Returns 120 (5! = 1×2×3×4×5) - number of ways to arrange 5 distinct items.
Zero Factorial
=FACT(0)Returns 1, as 0! is mathematically defined as 1.
Non-Integer Input
=FACT(1.9)Returns 1, truncating 1.9 to integer 1.
Negative Number Error
=FACT(-1)Returns #NUM! error for negative inputs.
Frequently Asked Questions
Common Errors and Solutions
#NUM!
Cause: Negative number input
Solution: Use only nonnegative numbers (0 or positive).
#VALUE!
Cause: Non-numeric input
Solution: Ensure the number argument contains valid numeric data.
Notes
- Maximum reliable input is around 170 due to Excel's number precision limits.
- Beyond 170, results may lose precision or overflow.
- Ideal for permutation calculations: P(n,r) = FACT(n)/(FACT(n-r))
- Use FACTDOUBLE for double factorials when needed
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003 and earlier
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+