ISOMITTED
Unsupported (not recognized)Category: Information · Last tested 2026-08-31
Real compatibility results for the ISOMITTED function: executed in 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 | — | No — file could not be opened | n/a |
| Google Sheets | No | Yes (Drive import, 2026-08-31) | Unsupported (not recognized) |
| LibreOffice Calc | No | Yes (25.8.7.3, 2026-08-31) | Unsupported (not recognized) |
LibreOffice version history
We executed the same test cases under each LibreOffice release to show exactly when ISOMITTED’s support changed — not documentation claims, real results.
| LibreOffice version | Verdict | Tested |
|---|---|---|
| 24.2.0.3 | Unsupported (not recognized) | 2026-08-31 |
| 24.8.7.2 | Unsupported (not recognized) | 2026-08-31 |
| 25.2.0.3 | Unsupported (not recognized) | 2026-08-31 |
| 25.8.7.3 | Unsupported (not recognized) | 2026-08-31 |
Why isn't ISOMITTED working in LibreOffice?
LibreOffice Calc does not implement ISOMITTED as of 25.8.7.3 — in our
executed tests it returns a #NAME? (unrecognized function) error. This is not a typo or a
settings problem, and saving the file as .xlsx does not change it: the function simply isn’t
available yet.
The same formula is documented for Excel.
Watch the LibreOffice version support page —
we re-run every test on each new release, so it will flip to Supported here as soon as it lands.
Why isn’t ISOMITTED working in Google Sheets?
Google Sheets does not implement ISOMITTED: we imported the formula into
Sheets on 2026-08-31 and every case came back #NAME?
(unrecognized function). Sheets is a rolling service with no version to pin, so this is a
statement about the service on that date, and Google’s own
function list does not document it either. Rewrite the formula with a documented
Sheets equivalent — see the
Excel ↔ Sheets equivalents table.
.xlsx to OneDrive and opening it, and its file-open refuses any workbook whose stored formulas carry the _xlpm./LAMBDA storage serialization (“Couldn’t Open the Workbook”, no cell-level diagnostic). Proven by bisect: the 40-function chunk carrying it was refused, the same chunk minus LAMBDA/LET/ISOMITTED opened, and those three alone were refused again. Desktop Excel implements ISOMITTED — it is Microsoft’s own function — and LibreOffice’s executed verdict for it is published below. What we cannot do is carry it into the web engine to measure, so no Excel-for-the-web verdict is drawn. The irony is the finding: Excel for the web will not open a file containing Excel’s own LAMBDA-family storage serialization.
Discovered quirks
-
=LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,) on
Google Sheets returned
#NAME?, but the documented/expected
result is Missing second argument.
Provenance
Microsoft's page publishes exactly this formula -- "Example 1: Check for a missing parameter and return a friendly string ... =LAMBDA(x,y, IF(ISOMITTED(y),\"Missing second argument\",x+y))(1,)" -- and the trailing comma with nothing after it is the point: y is supplied as omitted. ISOMITTED(y) is therefore TRUE and the IF returns the friendly string. The result string is fixed by the formula itself, so nothing here is derived or guessed. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it.; MISMATCH vs expected: expected 'Missing second argument', got '#NAME?'
-
=LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,2) on
Google Sheets returned
#NAME?, but the documented/expected
result is 3.
Provenance
The control for Microsoft's own example: with y = 2 present, ISOMITTED(y) must be FALSE and the IF must fall through to x+y = 1+2 = 3. Without this case a function that returned TRUE unconditionally would pass the documented example. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it.; MISMATCH vs expected: expected 3, got '#NAME?'
-
=LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,) on
LibreOffice Calc returned
#VALUE!, but the documented/expected
result is Missing second argument.
Provenance
Microsoft's page publishes exactly this formula -- "Example 1: Check for a missing parameter and return a friendly string ... =LAMBDA(x,y, IF(ISOMITTED(y),\"Missing second argument\",x+y))(1,)" -- and the trailing comma with nothing after it is the point: y is supplied as omitted. ISOMITTED(y) is therefore TRUE and the IF returns the friendly string. The result string is fixed by the formula itself, so nothing here is derived or guessed. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it.; MISMATCH vs expected: expected 'Missing second argument', got '#VALUE!'
-
=LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,2) on
LibreOffice Calc returned
#VALUE!, but the documented/expected
result is 3.
Provenance
The control for Microsoft's own example: with y = 2 present, ISOMITTED(y) must be FALSE and the IF must fall through to x+y = 1+2 = 3. Without this case a function that returned TRUE unconditionally would pass the documented example. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it.; MISMATCH vs expected: expected 3, got '#VALUE!'
Executed test cases
Google Sheets (executed 2026-08-31 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 |
|---|---|---|---|---|
| =LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,) | Microsoft's documented Example 1, called with the second argument omitted | #NAME? | Missing second argumentProvenanceMicrosoft's page publishes exactly this formula -- "Example 1: Check for a missing parameter and return a friendly string ... =LAMBDA(x,y, IF(ISOMITTED(y),\"Missing second argument\",x+y))(1,)" -- and the trailing comma with nothing after it is the point: y is supplied as omitted. ISOMITTED(y) is therefore TRUE and the IF returns the friendly string. The result string is fixed by the formula itself, so nothing here is derived or guessed. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it. |
Mismatch |
| =LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,2) | The same documented LAMBDA with the second argument actually supplied | #NAME? | 3ProvenanceThe control for Microsoft's own example: with y = 2 present, ISOMITTED(y) must be FALSE and the IF must fall through to x+y = 1+2 = 3. Without this case a function that returned TRUE unconditionally would pass the documented example. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it. |
Mismatch |
| =ISOMITTED(A2) | PROBE: ISOMITTED called on its own, the only way to ask an engine about this function rather than about LAMBDA | #NAME? | ProvenanceMicrosoft documents ISOMITTED only as a LAMBDA helper -- "Checks whether the value in a LAMBDA is missing" -- and publishes no behaviour for a call outside one, so no expected value is derived and none is invented. The case exists because it is the ONLY way to put the question to an engine directly: the two documented cases in this file are LAMBDA calls, and an engine without LAMBDA fails on the LAMBDA before ISOMITTED is ever looked up, so their results say nothing about ISOMITTED itself. FOR THE RECORD, all four LibreOffice builds return #NAME? here -- under the plain name, the _xlfn. storage form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike -- which is what establishes that ISOMITTED is genuinely absent from LibreOffice rather than merely unreachable there. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it. |
Error |
LibreOffice Calc 25.8.7.3 (tested 2026-08-31)
| Formula | Description | Result | Expected | Verdict |
|---|---|---|---|---|
| =LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,) | Microsoft's documented Example 1, called with the second argument omitted | #VALUE! | Missing second argumentProvenanceMicrosoft's page publishes exactly this formula -- "Example 1: Check for a missing parameter and return a friendly string ... =LAMBDA(x,y, IF(ISOMITTED(y),\"Missing second argument\",x+y))(1,)" -- and the trailing comma with nothing after it is the point: y is supplied as omitted. ISOMITTED(y) is therefore TRUE and the IF returns the friendly string. The result string is fixed by the formula itself, so nothing here is derived or guessed. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it. |
Mismatch |
| =LAMBDA(x,y,IF(ISOMITTED(y),"Missing second argument",x+y))(1,2) | The same documented LAMBDA with the second argument actually supplied | #VALUE! | 3ProvenanceThe control for Microsoft's own example: with y = 2 present, ISOMITTED(y) must be FALSE and the IF must fall through to x+y = 1+2 = 3. Without this case a function that returned TRUE unconditionally would pass the documented example. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it. |
Mismatch |
| =ISOMITTED(A2) | PROBE: ISOMITTED called on its own, the only way to ask an engine about this function rather than about LAMBDA | #NAME? | ProvenanceMicrosoft documents ISOMITTED only as a LAMBDA helper -- "Checks whether the value in a LAMBDA is missing" -- and publishes no behaviour for a call outside one, so no expected value is derived and none is invented. The case exists because it is the ONLY way to put the question to an engine directly: the two documented cases in this file are LAMBDA calls, and an engine without LAMBDA fails on the LAMBDA before ISOMITTED is ever looked up, so their results say nothing about ISOMITTED itself. FOR THE RECORD, all four LibreOffice builds return #NAME? here -- under the plain name, the _xlfn. storage form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike -- which is what establishes that ISOMITTED is genuinely absent from LibreOffice rather than merely unreachable there. ISOMITTED EXISTS ONLY INSIDE A LAMBDA. Its whole documented purpose is "Checks whether the value in a LAMBDA is missing and returns TRUE or FALSE", and its argument is documented as "The value you want to test, such as a LAMBDA parameter". So it cannot be exercised on its own: both asserted cases here are the LAMBDA call Microsoft itself publishes. It is an Excel for Microsoft 365 / Excel 2024 function only -- the page's Applies To line lists no perpetual release before 2024 -- and it is stored as _xlfn.ISOMITTED, which [MS-XLSX] section 2.2.3 lists prefixed. EXECUTED RESULT: LibreOffice has no LAMBDA at all, so these formulas cannot work there and do not: a five-spelling probe on all four builds (24.2.0.3, 24.8.7.2, 25.2.0.3, 25.8.7.3) returns #NAME? for =ISOMITTED(A1) under the plain name, the _xlfn. form, the COM.MICROSOFT. form, the ORG.OPENOFFICE. form and the _xlfn.ORG.OPENOFFICE. form alike, and =LAMBDA(x,x+1)(2) is itself an error on every build. This is a genuine missing function, not the storage-form gap this batch records for IMSEC/IMSECH/IMSINH/IMTAN -- there is no spelling under which LibreOffice computes it. |
Error |
Docs & syntax
- Excel (desktop): official documentation