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ISNUMBER Function in Calligra Sheets: Formula, Examples & Troubleshooting

Information Beginner Calligra Sheets

Learn the ISNUMBER formula in Calligra Sheets: determine whether a value is numerical, with reproducible examples, expected answers and compatibility cautions.

Verification status: Official documentation referenced; example outcomes independently reasoned or arithmetically checked where stated. Not executed in Calligra Sheets. How formula examples are checked

Quick answer: Use ISNUMBER to determine whether a value is numerical. The example below supplies exact inputs and independently calculated expected results, so you can check your formula before replacing the demonstration values with real workbook data.

Verification: The function is covered by a vendor reference or its published formula catalogue. The worked outputs here are independently reasoned, not screenshots or native test results from Calligra Sheets. Check release-specific support and argument details in the referenced vendor help.

Syntax and arguments

=ISNUMBER(value)

Cell or value to evaluate for numeric type. In formula syntax, square brackets mark optional arguments; do not type square brackets into an ordinary formula unless the particular function requires array notation. The separator shown is for the example locale and might change with spreadsheet settings.

When to use it: Use VALUE only after confirming a text entry represents a safe number.

Prepare the example inputs

In Calligra Sheets, place the sample rows in one sheet and enter examples using the documented semicolon (;) argument separator. Make sure the result cell is outside the source area. These two examples use literal values, so you can enter them into blank cells without first constructing a table. Their answers are independent calculations; dates must be displayed with an actual date format.

Worked example: exact formula and expected output

=ISNUMBER(125)

Expected result: TRUE. A literal number is numeric.

  1. Select an unused output cell (for example H2 if the practice table occupies A1:F9).
  2. Enter the formula exactly as shown, including the opening equals sign and quoted text.
  3. Compare the displayed answer to the expected result, then inspect the source cells if it differs.

For a range formula, the row numbers include data rows only unless the example explicitly refers to headers. A result that looks plausible may still be wrong if it references the wrong column.

Second example: a different input

=ISNUMBER("125")

Expected result: FALSE. Quoted 125 is text, not a number.

Enter this second example in a separate result cell. Both expected outcomes follow from the fixture or the explicit numbers; the packaged application has not been run.

Important edge cases and a common mistake

Watch out: A numeric-looking import can be text; formatting alone does not convert its type.

The KDE handbook is a source of functions recognized by the project, but version support and data-type coercion in a particular binary remain to be verified. Excel-style functions must not be assumed interchangeable.

Troubleshooting in Calligra Sheets

In Calligra, check the formula entry line for quoted conditions, semicolon delimiters and relative-versus-absolute references. If a value looks wrong, compare against the KDE handbook function entry before assuming Excel matching defaults.

If you get the wrong answer but no error, try these checks in order: (1) evaluate the simplified first example; (2) confirm the cell values and data types; (3) check the exact row and column boundaries; (4) verify quoted text, comparison operators and separators; (5) only then add more criteria or nested functions.

For a reproducible comparison with another spreadsheet product, use the same input values in both applications and record the installed version and locale. Different default matching behavior or handling of empty values can be a migration issue rather than a mathematical disagreement.

Moving this formula between spreadsheet programs

Calligra is a KDE spreadsheet with its own functions and argument conventions; Excel and other programs are not exact substitutes. Calligra normally separates formula arguments with semicolons.

Related guides already published for this function: Microsoft Excel | Google Sheets | WPS Spreadsheet | Collabora Office Calc | LibreOffice Calc

If a comparison tool says Not researched here, that means we do not yet have a checked guide for that software. It does not mean the software lacks this function. See the 12-program comparison tool for a guide-coverage matrix.

Official reference and editorial verification

Evidence level: Vendor-published function catalogue / formula overview, checked for this editorial batch on October 11, 2026; example outputs verified by direct reasoning/arithmetic where applicable. No execution in Calligra Sheets was performed. Some platform-, language- and release-specific edge cases remain for native testing.