ISLOGICAL

Supported, behaves as documented

Category: Information · Last tested 2026-09-01

Real compatibility results for the ISLOGICAL function: executed in Excel for the web, Google Sheets and LibreOffice Calc, with desktop Excel behavior from Microsoft’s official documentation (we do not run desktop Excel — Excel for the web is a different application and is executed separately). Syntax and links to that documentation are below.

Support matrix

Engine	Documented	Live-tested	Verdict
Excel (desktop)	Yes	No — documented only	n/a
Excel for the web	—	Yes (recalc, 2026-09-01)	Supported, behaves as documented
Google Sheets	Yes	Yes (Drive import, 2026-08-29)	Supported, behaves as documented
LibreOffice Calc	Yes	Yes (25.8.7.3, 2026-07-29)	Supported, behaves as documented

LibreOffice version history

We executed the same test cases under each LibreOffice release to show exactly when ISLOGICAL’s support changed — not documentation claims, real results.

LibreOffice version	Verdict	Tested
24.2.0.3	Supported, behaves as documented	2026-08-29
24.8.7.2	Supported, behaves as documented	2026-08-29
25.2.0.3	Supported, behaves as documented	2026-08-29
25.8.7.3	Supported, behaves as documented	2026-07-29

Executed test cases

Excel for the web (executed 2026-09-01 via OneDrive recalculation)

These values come from Excel for the web, not from desktop Excel. They are two different implementations of the calculation engine, and this run measured only the web one: the corpus was uploaded to OneDrive as .xlsx, recalculated by Excel for the web on open, and downloaded again for readback. Excel for the web is a rolling service with no pinnable version, so the run is identified by its date. Where a value here disagrees with the Expected column — which is Microsoft’s documentation of the desktop product — we cannot tell you whether the web engine diverges from the desktop one or the documentation is wrong about both, because we do not run desktop Excel.

Formula	Description	Result	Expected	Verdict
=ISLOGICAL(TRUE)	TRUE is a logical value -> TRUE	True	True	Matched
=ISLOGICAL(FALSE)	FALSE is a logical value -> TRUE	True	True	Matched
=ISLOGICAL(A1)	A plain number is not a logical value -> FALSE	False	False Provenance Even though 1 and TRUE are arithmetically interchangeable, ISLOGICAL distinguishes the underlying boolean type from a number.	Matched
=ISLOGICAL(A1)	Text is not a logical value -> FALSE	False	False Provenance The text string "TRUE" is text, not the boolean TRUE.	Matched

Google Sheets (executed 2026-08-29 via Drive import)

Google Sheets is a rolling service with no pinnable version, so this run is identified by its date. The corpus was imported to Drive as .xlsx, recalculated by Sheets, and exported back for readback.

Formula	Description	Result	Expected	Verdict
=ISLOGICAL(TRUE)	TRUE is a logical value -> TRUE	True	True	Matched
=ISLOGICAL(FALSE)	FALSE is a logical value -> TRUE	True	True	Matched
=ISLOGICAL(A1)	A plain number is not a logical value -> FALSE	False	False Provenance Even though 1 and TRUE are arithmetically interchangeable, ISLOGICAL distinguishes the underlying boolean type from a number.	Matched
=ISLOGICAL(A1)	Text is not a logical value -> FALSE	False	False Provenance The text string "TRUE" is text, not the boolean TRUE.	Matched

LibreOffice Calc 25.8.7.3 (tested 2026-07-29)

Formula	Description	Result	Expected	Verdict
=ISLOGICAL(TRUE)	TRUE is a logical value -> TRUE	True	True	Matched
=ISLOGICAL(FALSE)	FALSE is a logical value -> TRUE	True	True	Matched
=ISLOGICAL(A1)	A plain number is not a logical value -> FALSE	False	False Provenance Even though 1 and TRUE are arithmetically interchangeable, ISLOGICAL distinguishes the underlying boolean type from a number.	Matched
=ISLOGICAL(A1)	Text is not a logical value -> FALSE	False	False Provenance The text string "TRUE" is text, not the boolean TRUE.	Matched

Docs & syntax

Excel (desktop): official documentation
Google Sheets: official documentation
LibreOffice Calc: official documentation

Where ISLOGICAL behaves differently

ISNUMBER(TRUE) is FALSE in Excel but TRUE in LibreOffice
In Excel a logical value is not a number, so ISNUMBER(TRUE) is FALSE - executed Google Sheets agrees. LibreOffice returns TRUE. The silent divergence and a safe rewrite.
TYPE(TRUE): Excel 4 vs LibreOffice 1
Excel documents TYPE(TRUE) as 4 and TYPE(A1:A3) as 64; LibreOffice returns 1 for both. The booleans-are-numbers theme breaks logic that branches on TYPE codes.