ISFORMULA Function (Gnumeric)

ISFORMULA answers whether a referenced cell contains a formula, not whether the formula’s current output is numeric or whether the formula succeeded. It can distinguish a hardcoded value from a calculated one in an audit. Gnumeric documents the function as OpenFormula-compatible. R1

=ISFORMULA(cell)

cell (required) is a reference to one cell. There are no optional arguments and no documented defaults. The formula returns the Boolean result TRUE when that referenced cell has a stored formula expression and FALSE when it does not. The GNOME source requires a cell-reference argument; it rejects a multi-cell range and a non-reference with a #REF! error. Those invalid-input results are derived from code inspection rather than native testing here. R1

Native-validation limits: All outputs are source/documentation-based expectations, not native Gnumeric observations.

Version and locale scope: Written against the official Gnumeric 1.12 Information manual, the public Gnumeric function catalogue and the GNOME-maintained source consulted on 2026-10-12. Gnumeric 1.12.62 is the current series release identified. Actual plugin/build availability and any localization effects must be confirmed in the reader’s installation. These guides use English names and Gnumeric’s manual convention of a leading = and comma-separated arguments. A single-argument function has no delimiter ambiguity; nested IF examples use commas and might need locale-appropriate adjustment. R1R4

1. Create a fresh Gnumeric worksheet. Enter the literal text In stock in A2, and enter the formulas exactly as shown in A3:A5. Leave A6 genuinely empty.
2. Enter =ISFORMULA(A2) in B2 and fill B2 down through B6, allowing relative references to follow each row.
3. Compare the results to the expected column. A text result that looks empty is not the same as an empty cell.

The expected classifications follow the gnm_cell_has_expr check in Gnumeric’s source and its documented distinction between formulas, ordinary values and errors. Gnumeric was not run to observe these five results. R2

Find an accidentally overwritten formula

When column A is intended to contain calculated amounts, put this in C3 and fill down:

=IF(ISFORMULA(A3),"Formula intact","Review: manual entry")

Expected in C3: Formula intact. If A3 is replaced with the literal number 24, expected: Review: manual entry even though the displayed value remains 24. This detects a process issue that comparing numeric outputs would miss. The IF branch behavior is independently reasoned from documented formula semantics. R2

Audit formula results separately from formula presence

=ISFORMULA(A5) is expected TRUE for a cell holding =NA(), but this does not mean its calculation is valid. Use a separate error check such as ISERROR when you need to assess the result. For the original expression text, inspect GET.FORMULA rather than expecting ISFORMULA to return the expression string. These are different diagnostic questions. R1

Probe the single-cell restriction before relying on bulk logic

• =ISFORMULA(A2:A3) — expected #REF! from the inspected GNOME implementation because its two endpoints are different cells.
• =ISFORMULA(42) — expected #REF! because the argument is not a cell reference.

These error outcomes are source-code interpretations, not screenshots or runtime observations. For per-cell checks, put a single-cell formula in each adjacent row rather than passing an entire range. R6

• A formula showing nothing is flagged TRUE. A formula such as ="" is stored as a formula, unlike a truly blank cell. Check the formula bar. R2
• A broken formula is still a formula. This test checks the presence of an expression, not success or accuracy. Pair it with a result/error test as appropriate. R2
• A range or literal causes an error in Gnumeric’s inspected source. Replace the argument with a direct single-cell reference; do not copy error behavior from other spreadsheet products. R6
• Unexpected parsing or an unknown function name: verify the leading =, function spelling, installed version and locale. No alternate aliases were established for this canonical function. R1
• Cross-sheet reference: Gnumeric supports sheet-qualified cell references, but the exact syntax and behavior across your workbook should be checked natively before relying on it; no tested cross-file example is asserted. R2

The Gnumeric manual states OpenFormula compatibility for ISFORMULA. Microsoft’s current Excel reference also lists an ISFORMULA function. Gnumeric’s public catalogue labels its implementation Unique to Gnumeric / No Testsuite; that is project metadata and should not be read as proof modern Excel lacks the function. Neither cross-product error-code equivalence nor native testing is claimed here. R1R7

GET.FORMULA · ISERROR · ISBLANK · IF.

Checked: 2026-10-12 UTC. These official references support the specific claims above:

• R1 Gnumeric Information functions — official function definitions, signatures, argument descriptions and compatibility notes.
• R2 Gnumeric cells, formulas, references and errors — formula input, Boolean versus text values, cell references and error interpretation.
• R3 Gnumeric public function catalogue — registration, implementation and project test-suite classification; catalogue totals are not the version-pinned 1.12.62 release registry.
• R4 Gnumeric locales — operating-system locale and formatting context.
• R5 Gnumeric 1.12.62 release announcement — current version context; this does not prove execution of these examples on every build.
• R6 Official Gnumeric 1.12.62 source archive — checksum-verified plugins/fn-info/functions.c help and callbacks inspected on 2026-10-13; source-level evidence, not native execution.
• R7 Microsoft’s Excel Information function reference — Excel’s separately documented availability, not a substitute for testing Gnumeric.

Validation: Official manuals and checksum-verified Gnumeric 1.12.62 source were inspected; expected outcomes were logically evaluated. No native Gnumeric execution, screenshots, locale regression or workbook round-trip tests were performed.