What's the maximum number I can use with FACT?

FACT works with integers 0 to 170 in most spreadsheets. Inputs above 170 return #NUM! error. FACT(0) returns 1 by mathematical convention; negative numbers are always undefined.

How do I calculate combinations of agents or tickets using FACT?

Apply the combination formula C(n,k) = n! / (k! × (n-k)!). Example: to select 2 agents from your 5-person team, use =FACT(5)/(FACT(2)*FACT(3)) = 10 possible pairings.

Why use FACT instead of PRODUCT?

FACT calculates n! directly (1 × 2 × 3 × ... × n), while PRODUCT multiplies any arbitrary range of cells. Use FACT when you specifically need a factorial; PRODUCT is better for flexible range multiplication.

Can I calculate factorials of decimal or negative numbers?

No; FACT only accepts non-negative integers. Decimals typically truncate or cause #VALUE! error, and negative numbers always produce #NUM!. Use INT or TRUNC to round decimals, or validate with IF first.

FACT function

FACT calculates the factorial of a number (n!), returning the product of all positive integers from 1 to n; use it for permutations and combinations.

=FACT(number)

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Arguments

How FACT reads its arguments

Argument	Required	Description
number	Required	A non-negative integer (0–170 in most spreadsheets); decimals are typically truncated or cause #VALUE! error, and negative numbers produce #NUM! error.

Returns

A positive integer representing n!, the product of all integers from 1 to n; FACT(0) returns 1 by convention.

Availability

Excel: All · Google Sheets: Supported

Worked examples

1. Calculate permutations of critical-priority tickets

Ticket ID	Priority	Agent	CSAT
TK-001	Critical	John Smith	5
TK-002	Critical	Sarah Chen	4

=FACT(2)

Result: 2

With 2 critical tickets in queue, FACT(2) returns 2! = 2 × 1 = 2, representing the two different orderings in which to process or assign them.

2. Calculate all possible shift arrangements for 5 agents

Agent Name	Tickets Assigned
John Smith	12
Sarah Chen	14
Mike Johnson	9
Emma Davis	11
David Lee	10

=FACT(5)

Result: 120

With 5 agents available, 5! = 5 × 4 × 3 × 2 × 1 = 120 unique ways to schedule or arrange them across work rotations.

3. Calculate combinations: choose 2 agents from 5 for a project team

Agent Name

John Smith

Sarah Chen

Mike Johnson

Emma Davis

David Lee

=FACT(5)/(FACT(2)*FACT(3))

Result: 10

Using the combination formula C(5,2) = 5!/(2!×3!) = 120/12 = 10, there are exactly 10 unique 2-person teams you can form from the 5 agents.

Common errors

Which FACT error are you seeing?

Error	Why it happens	How to fix it
#NUM!	FACT receives a negative number (e.g., FACT(-3)); factorials are mathematically undefined for negative integers.	Use ABS() to convert to positive, or validate inputs first: =IF(A1<0,"Invalid",FACT(A1)) to reject negative agent counts.
#VALUE!	FACT receives a text string instead of a number (e.g., FACT("Critical") or FACT(agent_name)).	Ensure the argument is numeric; use COUNTIF to extract counts first: =FACT(COUNTIF(B:B,"Critical")) to count tickets by priority.
#NUM!	FACT receives a number greater than 170; most spreadsheets cap factorials at 170 due to the astronomical size of the result.	Restrict inputs to 0–170; for larger values, use approximations like Stirling's formula or external computational tools.

Tips and when to use something else

Factorials explode in size: FACT(10) = 3,628,800 and FACT(20) exceeds 2 trillion. Even modest inputs quickly produce unmanageable results.
Use PRODUCT for arbitrary multiplication ranges; PRODUCT is more flexible. FACT specifically computes n × (n−1) × ... × 1 in strict order.
Combine FACT with IF for conditional logic: =IF(priority="Critical",FACT(5),FACT(3)) calculates different factorials based on ticket severity.
Most spreadsheets limit FACT to arguments 0–170. Use QUOTIENT to safely divide large factorial results in permutation formulas without overflow errors.

Related functions

PRODUCTReturns the product of all numeric values supplied as arguments, multiplying them together into a single result.SUMPRODUCTSUMPRODUCT multiplies arrays element-by-element and sums the results, useful for weighted totals and multi-criteria counting.QUOTIENTReturns the integer quotient of a division operation, discarding the remainder—useful for finding complete groups or batches from a total.IFThe IF function returns one value if a condition is true and another (or nothing) if it is false, letting you branch logic in a cell.

Frequently asked questions

What's the maximum number I can use with FACT?: FACT works with integers 0 to 170 in most spreadsheets. Inputs above 170 return #NUM! error. FACT(0) returns 1 by mathematical convention; negative numbers are always undefined.
How do I calculate combinations of agents or tickets using FACT?: Apply the combination formula C(n,k) = n! / (k! × (n-k)!). Example: to select 2 agents from your 5-person team, use =FACT(5)/(FACT(2)*FACT(3)) = 10 possible pairings.
Why use FACT instead of PRODUCT?: FACT calculates n! directly (1 × 2 × 3 × ... × n), while PRODUCT multiplies any arbitrary range of cells. Use FACT when you specifically need a factorial; PRODUCT is better for flexible range multiplication.
Can I calculate factorials of decimal or negative numbers?: No; FACT only accepts non-negative integers. Decimals typically truncate or cause #VALUE! error, and negative numbers always produce #NUM!. Use INT or TRUNC to round decimals, or validate with IF first.

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Reviewed 2026-09-17