FACT Function in Excel: Factorial

⏱ 1 min readUpdated 28 September 2026

MathLevel: IntermediateAvailable in: Excel 2007+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. Common errors and fixes
  5. Related functions

FACT returns n! (1 × 2 × … × n). It grows absurdly fast: FACT(20) is already about 2.4 quintillion.

Syntax

=FACT(number)
Argument What it means
number Non-negative; decimals are truncated.

Examples

Example 1

=FACT(5)

120 ways to order five books on a shelf.

Common errors and fixes

You see Why, and the fix
#NUM! Negative input, or above 170 (the result overflows Excel’s number limit).

COMBIN · PERMUT

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