The FACT function in Google Sheets is a handy tool under the Math category. It calculates the factorial of a non-negative number, which is essential when working with permutations and combinatorics.

In mathematics, factorial (denoted by n!) represents the product of a whole number and all the positive integers less than it. It’s used to determine the number of ways to arrange a set of distinct objects.

For example, the letters X, Y, and Z can be arranged in 6 different ways:

XYZ, XZY, YXZ, YZX, ZXY, ZYX

That’s because:

3! = 3 × 2 × 1 = 6

Let’s see how to use the FACT function in Google Sheets to compute factorials like this.

FACT Function in Google Sheets – Syntax and Arguments

FACT(value)

value – A non-negative number or cell reference for which you want to calculate the factorial.

Notes

• If value is not an integer, it is truncated (e.g., 3.9 becomes 3).
• If the referenced cell is blank, Google Sheets treats it as 0, and FACT(0) returns 1.
• If the input is text, the result is #VALUE!.
• If the value is negative, FACT returns #NUM!.

Formula Examples

Example 1 – Using a Hardcoded Number

=FACT(3)

Returns 6.

Example 2 – Using a Cell Reference

If B2 contains the number 3, use:

=FACT(B2)

Returns 6.

Array Formula Usage of the FACT Function in Google Sheets

Want to calculate the factorials of numbers 1 to 10? Here are three different ways:

Method 1 – Manual Fill (Non-Array Formula)

• Enter numbers 1 to 10 in cells A1:A10
• In B1, enter:
  =FACT(A1)
• Copy down to B10

Method 2 – Apply FACT to a Range with ArrayFormula

=ArrayFormula(FACT(A1:A10))

Put this in B1 to compute all 10 factorials at once.

Method 3 – Use SEQUENCE to Generate Numbers

=ArrayFormula(FACT(SEQUENCE(10, 1)))

No need to manually input numbers. SEQUENCE(10, 1) generates values from 1 to 10.

Inverse Factorial in Google Sheets

What if you’re given a factorial value like 3628800, and you want to find the original number? In other words, you want to compute the inverse factorial in Google Sheets.

Here’s a formula that does just that:

Formula to Get Inverse Factorial in Google Sheets

Assume A1 contains the factorial value.

=XMATCH(1, SCAN(A1, SEQUENCE(1000), LAMBDA(acc, val, acc/val)))

How the Inverse Factorial Formula Works

• SEQUENCE(1000) generates numbers from 1 to 1000.
• SCAN starts with the factorial value in cell A1 and keeps dividing it by each value in the sequence.
• The LAMBDA defines how each step divides the accumulated result by the next number in the sequence. The acc parameter holds the intermediate result at each step.
• When the result becomes exactly 1, we know we’ve reversed all the factorial multiplications.
• XMATCH(1, …) returns the position where the result equals 1 — that is, the original number whose factorial is in A1.

Tip – Adjust Range If Needed

If the formula returns #N/A, increase 1000 to a higher number to search a larger range.

Conclusion

The FACT function in Google Sheets makes it easy to calculate factorials for everything from simple math problems to advanced permutations.

And with a little creativity, you can even compute the inverse factorial in Google Sheets, making your spreadsheet truly dynamic.

Thanks for reading!