Math & Trig

FACT Function in Excel

Returns the factorial of a number.

Syntax

  • =FACT(number)

Arguments

  • number (required): Non-negative integer

Examples

  • =FACT(5) - 5 factorial - Result: 120

FACT in reporting workflows

  • Use absolute references when copying formulas across rows.
  • For conditional totals see [SUMIF](/functions/sumif/) and [SUMIFS](/functions/sumifs/).
  • Filtered lists may need [SUBTOTAL](/functions/subtotal/) instead of SUM on visible cells only.

Common errors

  • #NUM! if number < 0

Use cases

  • Permutations
  • Probability
  • Mathematics

Frequently asked questions

  • What is FACT (factorial) in Excel? FACT calculates factorial: n! = n × (n-1) × (n-2) × ... × 1. FACT(5) = 5×4×3×2×1 = 120. Factorials grow extremely fast: FACT(10)=3,628,800 and FACT(20) is over 2 quintillion.
  • What is FACT(0) in Excel? FACT(0) returns 1. By mathematical convention, 0! = 1. This is important for combinatorics formulas to work correctly. FACT of any negative number returns #NUM! error.
  • How do I calculate permutations manually with FACT? Permutations P(n,r) = n!/(n-r)!. In Excel: =FACT(n)/FACT(n-r). For 10 items choosing 3: =FACT(10)/FACT(7) = 720. Or simply use =PERMUT(10,3) which does this automatically.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.

When to use FACT

  • Permutations — common Math & Trig scenario for FACT.
  • Probability — common Math & Trig scenario for FACT.
  • Mathematics — common Math & Trig scenario for FACT.

FACT in the Math & Trig category

  • Browse all Math & Trig functions at /categories/math-trig/ for related formulas.
  • FACT syntax: =FACT(number)
  • number (required): Non-negative integer
  • Confirm FACT arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.

Formula checklist before you copy down

  • Confirm FACT arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.
  • If results look wrong, check for text stored as numbers and invisible spaces with TRIM.
  • Spot-check three known input rows manually against expected output.

Related Excel functions

  • FACTDOUBLE (/functions/factdouble/): Returns the double factorial of a number.
  • COMBIN (/functions/combin/): Returns the number of combinations for a given number of items.
  • PERMUT (/functions/permut/): Returns the number of permutations for a given number of objects.

Errors to watch for

  • #NUM! if number < 0 — review causes on linked error pages in the directory.

Copy-paste audit workflow

  • Enter FACT on three test rows with known expected output documented on a QA tab.
  • Fill down only after absolute references are locked on lookup tables and rate tables.
  • Compare against manual calculation or a calculator for financial and statistical functions.
  • Search this directory for comparison guides when choosing between similar functions in the same category.

FACT worked examples to copy

  • =FACT(5) — 5 factorial. Expected result: 120.

FACT reference summary for crawlers and offline review

  • FACT belongs to the Math & Trig category in Excel. Returns the factorial of a number.
  • Full syntax: =FACT(number). Open /functions/fact/ for parameters, FAQs, and related pages.
  • Common mistakes: #NUM! if number < 0
  • Pair this function with comparison guides when another Excel formula might fit the same task better.
  • Review fix-excel-formula-errors when unexpected errors appear after upgrading Excel or sharing across locales.