Syntax
FACT(number)
| Parameter | Description |
|---|---|
| number | Parameter of the FACT function. |
Examples
Basic factorial
Formula
=FACT(5)
Returns 120 (5×4×3×2×1 = 120). There are 120 ways to arrange 5 distinct items.
Zero factorial
Formula
=FACT(0)
Returns 1. By mathematical convention, 0! = 1. This is important for combinatorial formulas to work correctly.
Larger factorial
Formula
=FACT(10)
Returns 3,628,800. Factorials grow extremely fast — 10 items can be arranged in over 3.6 million ways.
Common Errors
#NUM!
Negative numbers don't have factorials. =FACT(-1) returns #NUM!.
#VALUE!
Non-numeric input like text returns #VALUE!.
Tips
Factorials grow fast
FACT(20) is already over 2.4 quintillion. Most spreadsheets can handle up to about FACT(170) before overflowing.
Non-integers are truncated
FACT(5.7) returns FACT(5) = 120. The decimal part is truncated before computing the factorial.
Use COMBIN instead
For combinations, use =COMBIN(n,k) instead of =FACT(n)/(FACT(k)*FACT(n-k)). It's cleaner and avoids overflow for large values.
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