FACT Function in ONLYOFFICE Spreadsheet Editor: Factorials and Combinations

FACT calculates a factorial. In mathematics, for a nonnegative integer n, n! = n×(n-1)×...×1 and by definition 0! = 1. Factorials count ordered arrangements and support permutation and combination calculations.

Mathematically 0! = 1, 1! = 1, and n! = n×(n-1)! for each positive integer n. The values grow rapidly: 10! is 3,628,800; 12! is 479,001,600. The reference confirms that FACT returns a factorial, while these numeric examples are independently calculated, not native outputs.

=FACT(number)

There is exactly one required argument and no documented optional arguments or default value. The official reference describes it as “a numeric value,” but does not enumerate exact behaviour for negative values, decimals, text or extremes; do not label Microsoft Excel behaviour as ONLYOFFICE behaviour. These argument rules are grounded in the ONLYOFFICE FACT function reference (accessed 2026-10-13 UTC).

1. Open a scratch workbook in ONLYOFFICE Spreadsheet Editor, or create a blank sheet. These are test instructions, not a claim of native editor execution.
2. Select the specified cells and type the values exactly as displayed in the table below. Put the listed formula in the indicated result cell (or type the first formula and use the fill handle to copy it down).
3. In the English interface, type a leading = and use commas to separate arguments. The official Insert Functions guide documents both this entry workflow and comma separation in its English examples.
4. Inspect the result and compare it to the independently calculated expected number. Any different output is evidence to investigate, not proof the documentation is incorrect; check value types and formula-language settings first.
5. Change one input and verify that the result recalculates. The official guide documents automatic workbook recalculation by default and a Formula → Calculation control when needed.

Validation classification: The function signature and documented argument description were checked against the vendor reference. All numbers below were calculated separately using Python’s standard math module, then sanity-checked using mathematical identities. Native execution: not performed; no cell output or exact error code was observed.

These examples use English ONLYOFFICE function names, commas, and a decimal point only where relevant. The Advanced Settings documentation describes independently configurable formula-language and region settings; it does not establish which exact translated names or separators are supported by every installation or version. Do not silently replace commas, assume identical localized names, or interpret a number containing locale separators until testing the target editor.

The official Spreadsheet Editor function catalogue documents the English function names in the current, unversioned ONLYOFFICE Help Center. It is not a release-by-release runtime compatibility table. ONLYOFFICE Desktop Editors and browser-hosted Docs have separate release histories; neither the function page nor the current catalogue identifies the first Desktop, cloud or self-hosted release for this function. The exact tested build matrix remains unverified. In particular, an identically named function in Excel or Google Sheets is not evidence for ONLYOFFICE’s coercion rules, errors, array treatment or display precision. No cross-product formula-execution test was performed.

Type the integers 0 through 12 into A2:A14. In B2 enter =FACT(A2) and fill down through B14. Compare with the independently calculated values in the table; no native result is claimed.

How results were computed: Python math.factorial using integer inputs, then checked against divisibility / multiplicative or factorial identities. Formulas are intended as reproducible worksheet instructions, not observed workbook outputs. The exact display (e.g., number separators, decimals, scientific notation) can vary by editor and regional settings.

Paste each into a blank scratch cell. Expected numbers are independent mathematical calculations; the exact success/error outcome of the native implementation remains to be tested.

Count ways to arrange distinct items

If 6 different books are placed in order on a shelf, the expected number of arrangements is =FACT(6) → 720. This assumes each book is distinguishable, each is used exactly once, and order matters. It does not apply directly when books are duplicates.

Choose a group without caring about order

A group of 3 from 8 distinct people can be chosen in 8!/(3!×5!) ways. Enter =FACT(8)/(FACT(3)*FACT(5)); the expected result is 56. The numerator counts ordered arrangements; dividing removes order duplicates and the unused positions. If your target editor offers a distinct COMBIN function, its documented syntax should be checked before comparing results; this formula alone is sufficient mathematically.

Ordered selections without replacement

To fill 3 distinct positions from 7 distinct candidates, enter =FACT(7)/FACT(4). The expected count is 210 because 7×6×5=210. If positions are not distinct, use a combination rather than permutation calculation.

Build an input guard before evaluating FACT

With A2 as a user-entered value, a cautious scratch-sheet example is:

=IF(AND(A2>=0,A2=INT(A2)),FACT(A2),"Enter a nonnegative integer")

This uses other documented functions (IF, AND, INT) to block negative and fractional numeric entries in a typical numeric-data workflow. It has not been executed in ONLYOFFICE; text coercion and error propagation for the comparison expressions remain unverified. It is not a substitute for a formally tested native input-validation rule.

Precision and growth

A factorial grows so quickly that it eventually exceeds the precision or range of typical spreadsheet floating-point numbers. Do not assert an exact largest supported integer, a specific overflow threshold, or a precise error message without executing FACT in each target ONLYOFFICE build. Smaller integers with exact expected mathematical outputs are appropriate for this review manuscript.

Important: The vendor function article does not specify literal error codes for invalid values, decimal truncation, text coercion, mixed arrays or particular calculation overflow behaviour. A different spreadsheet application’s documentation does not establish ONLYOFFICE’s result. Before relying on undocumented behavior, record results natively in representative Desktop and browser versions with each regional setting in scope.

Native input coercion, invalid-input errors, historical release support, localized formula entry and workbook round trips remain untested.