ASC

Quirk found

Category: Text · Last tested 2026-09-01

Real compatibility results for the ASC 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)	Quirk found
Google Sheets	Yes	Yes (Drive import, 2026-08-31)	Supported, behaves as documented
LibreOffice Calc	Yes	Yes (25.8.7.3, 2026-08-31)	Quirk found

LibreOffice version history

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

LibreOffice version	Verdict	Tested
24.2.0.3	Quirk found	2026-08-31
24.8.7.2	Quirk found	2026-08-31
25.2.0.3	Quirk found	2026-08-31
25.8.7.3	Quirk found	2026-08-31

Why isn't ASC working in LibreOffice?

ASC exists in LibreOffice 25.8.7.3, but it is not a drop-in match for Excel — our executed tests found real behavioral differences (detailed in the test results on this page). If a formula that works in Excel or Google Sheets misbehaves in LibreOffice, compare your usage against the failing cases above before assuming your data is wrong.

Discovered quirks

=ASC("ＥＸＣＥＬ") on Excel for the web returned ＥＸＣＥＬ, but the documented/expected result is EXCEL.
Provenance
The page's second example is the same word in full-width characters, but it is rendered as inline images so the literal argument cannot be copied from the page; this case reconstructs it from the documented rule that the function "changes full-width (double-byte) characters to half-width (single-byte) characters". The argument is U+FF25 U+FF38 U+FF23 U+FF25 U+FF2C (FULLWIDTH LATIN CAPITAL E X C E L), whose documented half-width forms are the ASCII letters EXCEL; MISMATCH vs expected: expected 'EXCEL', got 'ＥＸＣＥＬ'
=ASC("Ａ１２３　") on Excel for the web returned Ａ１２３　, but the documented/expected result is A123 .
Provenance
Derived from the same documented full-width-to-half-width rule: U+FF21 -> A, U+FF11/FF12/FF13 -> 1/2/3, and U+3000 IDEOGRAPHIC SPACE -> U+0020 half-width space, giving the five-character string "A123 " (trailing half-width space); MISMATCH vs expected: expected 'A123 ', got 'Ａ１２３\u3000'
=ASC("Ａ１２３　") on LibreOffice Calc returned A123U+3000, but the documented/expected result is A123U+0020.
Provenance
Derived from the same documented full-width-to-half-width rule: U+FF21 -> A, U+FF11/FF12/FF13 -> 1/2/3, and U+3000 IDEOGRAPHIC SPACE -> U+0020 half-width space, giving the five-character string "A123 " (trailing half-width space); MISMATCH vs expected: expected 'A123 ', got 'A123\u3000'

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
=ASC("EXCEL")	Microsoft's documented worked example: text with no full-width characters is returned unchanged	EXCEL	EXCEL Provenance Microsoft's page publishes this example verbatim: '=ASC("EXCEL") equals "EXCEL"'. The documentation adds "If text does not contain any full-width letters, text is not changed"	Matched
=ASC("ＥＸＣＥＬ")	Full-width (double-byte) Latin letters converted to half-width	ＥＸＣＥＬ	EXCEL Provenance The page's second example is the same word in full-width characters, but it is rendered as inline images so the literal argument cannot be copied from the page; this case reconstructs it from the documented rule that the function "changes full-width (double-byte) characters to half-width (single-byte) characters". The argument is U+FF25 U+FF38 U+FF23 U+FF25 U+FF2C (FULLWIDTH LATIN CAPITAL E X C E L), whose documented half-width forms are the ASCII letters EXCEL	Mismatch
=ASC("Ａ１２３　")	Full-width letter, full-width digits and an ideographic space	Ａ１２３	A123 Provenance Derived from the same documented full-width-to-half-width rule: U+FF21 -> A, U+FF11/FF12/FF13 -> 1/2/3, and U+3000 IDEOGRAPHIC SPACE -> U+0020 half-width space, giving the five-character string "A123 " (trailing half-width space)	Mismatch
=LEN(ASC("ＥＸＣＥＬ"))	The conversion is character-for-character, so the length is unchanged	5	5 Provenance Excel documents ASC as changing full-width characters to half-width characters, a one-for-one character mapping rather than an encoding change, so a five-character input yields a five-character result. This case separates a genuine width conversion from a byte-level reinterpretation	Matched

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
=ASC("EXCEL")	Microsoft's documented worked example: text with no full-width characters is returned unchanged	EXCEL	EXCEL Provenance Microsoft's page publishes this example verbatim: '=ASC("EXCEL") equals "EXCEL"'. The documentation adds "If text does not contain any full-width letters, text is not changed"	Matched
=ASC("ＥＸＣＥＬ")	Full-width (double-byte) Latin letters converted to half-width	EXCEL	EXCEL Provenance The page's second example is the same word in full-width characters, but it is rendered as inline images so the literal argument cannot be copied from the page; this case reconstructs it from the documented rule that the function "changes full-width (double-byte) characters to half-width (single-byte) characters". The argument is U+FF25 U+FF38 U+FF23 U+FF25 U+FF2C (FULLWIDTH LATIN CAPITAL E X C E L), whose documented half-width forms are the ASCII letters EXCEL	Matched
=ASC("Ａ１２３　")	Full-width letter, full-width digits and an ideographic space	A123	A123 Provenance Derived from the same documented full-width-to-half-width rule: U+FF21 -> A, U+FF11/FF12/FF13 -> 1/2/3, and U+3000 IDEOGRAPHIC SPACE -> U+0020 half-width space, giving the five-character string "A123 " (trailing half-width space)	Matched
=LEN(ASC("ＥＸＣＥＬ"))	The conversion is character-for-character, so the length is unchanged	5	5 Provenance Excel documents ASC as changing full-width characters to half-width characters, a one-for-one character mapping rather than an encoding change, so a five-character input yields a five-character result. This case separates a genuine width conversion from a byte-level reinterpretation	Matched

LibreOffice Calc 25.8.7.3 (tested 2026-08-31)

Formula	Description	Result	Expected	Verdict
=ASC("EXCEL")	Microsoft's documented worked example: text with no full-width characters is returned unchanged	EXCEL	EXCEL Provenance Microsoft's page publishes this example verbatim: '=ASC("EXCEL") equals "EXCEL"'. The documentation adds "If text does not contain any full-width letters, text is not changed"	Matched
=ASC("ＥＸＣＥＬ")	Full-width (double-byte) Latin letters converted to half-width	EXCEL	EXCEL Provenance The page's second example is the same word in full-width characters, but it is rendered as inline images so the literal argument cannot be copied from the page; this case reconstructs it from the documented rule that the function "changes full-width (double-byte) characters to half-width (single-byte) characters". The argument is U+FF25 U+FF38 U+FF23 U+FF25 U+FF2C (FULLWIDTH LATIN CAPITAL E X C E L), whose documented half-width forms are the ASCII letters EXCEL	Matched
=ASC("Ａ１２３　")	Full-width letter, full-width digits and an ideographic space	A123U+3000	A123U+0020 Provenance Derived from the same documented full-width-to-half-width rule: U+FF21 -> A, U+FF11/FF12/FF13 -> 1/2/3, and U+3000 IDEOGRAPHIC SPACE -> U+0020 half-width space, giving the five-character string "A123 " (trailing half-width space)	Mismatch
=LEN(ASC("ＥＸＣＥＬ"))	The conversion is character-for-character, so the length is unchanged	5	5 Provenance Excel documents ASC as changing full-width characters to half-width characters, a one-for-one character mapping rather than an encoding change, so a five-character input yields a five-character result. This case separates a genuine width conversion from a byte-level reinterpretation	Matched

Docs & syntax

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