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ASC Function in Excel

Changes full-width (double-byte) characters to half-width (single-byte) characters.

Syntax

  • =ASC(text)

Arguments

  • text (required): Text to convert

Examples

  • =ASC("ＥＸＣＥＬ") - Convert full-width to half-width - Result: EXCEL

Excel ASC function documentation

  • ASC converts full-width (double-byte) characters to half-width (single-byte) characters.
  • Syntax: =ASC(text). Common in East Asian text normalization workflows.
  • Use ASC before joins, lookups, or duplicate checks to standardize character width.
  • Text function category: [/categories/text/](/categories/text/).

ASC syntax and character conversion behavior

  • text is required and can be a literal string or cell reference.
  • ASC primarily impacts languages and inputs where full-width forms are common.
  • Combine ASC with TRIM and CLEAN for robust imported text cleanup.
  • Results vary by language support and installed locale behavior.

Step-by-step: normalize customer IDs

  • Step 1 - Place raw IDs in A2:A100 that may include mixed-width characters.
  • Step 2 - In B2 use =ASC(A2).
  • Step 3 - Copy down and compare duplicates on normalized IDs only.
  • Step 4 - Use normalized values in lookup keys and exports.

ASC vs JIS vs manual cleaning

  • ASC converts full-width to half-width for consistency in system keys.
  • JIS performs the opposite direction, from half-width to full-width.
  • Manual replacements are slower and less reliable at scale.
  • Display formatting with [TEXT](/functions/text/) does not solve width inconsistencies.

Worked examples to copy

  • Basic conversion: =ASC(A2).
  • Inline text: =ASC("ＡＢＣ１２３").
  • Trim + convert: =TRIM(ASC(A2)).
  • Lookup helper key: =UPPER(TRIM(ASC(A2))).

People also ask

  • When should I use ASC? - When full-width and half-width text must be standardized.
  • Does ASC change all symbols? - It targets convertible full-width characters.
  • ASC vs CLEAN? - CLEAN removes control characters; ASC normalizes character width.
  • Can ASC fix lookup mismatches? - Yes, when mismatches are caused by width differences.

Common errors

  • Only affects double-byte characters

Use cases

  • Asian text processing
  • Data cleaning
  • Character conversion

Frequently asked questions

  • What is ASC function used for? ASC converts full-width (double-byte) characters to half-width (single-byte) characters. In Asian languages, characters can be full-width (taking two bytes) or half-width. ASC standardizes text to half-width for consistency.
  • When do I need ASC? Use ASC when working with Japanese, Chinese, or Korean text that may contain full-width characters. Full-width 'ＡＢＣＤ' looks different from half-width 'ABCD'. ASC converts to half-width for consistent formatting and comparisons.
  • What's the difference between ASC and JIS? ASC converts full-width to half-width. JIS does the opposite - converts half-width to full-width. Use ASC for compact display and data processing; use JIS when full-width formatting is required.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.

When to use ASC

  • Asian text processing — common Text scenario for ASC.
  • Data cleaning — common Text scenario for ASC.
  • Character conversion — common Text scenario for ASC.

ASC in the Text category

  • Browse all Text functions at /categories/text/ for related formulas.
  • ASC syntax: =ASC(text)
  • text (required): Text to convert
  • Confirm ASC arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.

Formula checklist before you copy down

  • Confirm ASC arguments match the syntax shown above before filling down.
  • Lock table and range references with $ when copying formulas across rows or sheets.
  • If results look wrong, check for text stored as numbers and invisible spaces with TRIM.
  • Spot-check three known input rows manually against expected output.

Related Excel functions

  • JIS (/functions/jis/): Changes half-width (single-byte) characters to full-width (double-byte) characters.
  • CLEAN (/functions/clean/): Removes all non-printable characters from text.
  • TRIM (/functions/trim/): Removes extra spaces from text, leaving only single spaces between words.

Errors to watch for

  • Only affects double-byte characters — review causes on linked error pages in the directory.

Copy-paste audit workflow

  • Enter ASC on three test rows with known expected output documented on a QA tab.
  • Fill down only after absolute references are locked on lookup tables and rate tables.
  • Compare against manual calculation or a calculator for financial and statistical functions.
  • Search this directory for comparison guides when choosing between similar functions in the same category.

ASC worked examples to copy

  • =ASC("ＥＸＣＥＬ") — Convert full-width to half-width. Expected result: EXCEL.

ASC reference summary for crawlers and offline review

  • ASC belongs to the Text category in Excel. Changes full-width (double-byte) characters to half-width (single-byte) characters.
  • Full syntax: =ASC(text). Open /functions/asc/ for parameters, FAQs, and related pages.
  • Common mistakes: Only affects double-byte characters
  • Pair this function with comparison guides when another Excel formula might fit the same task better.
  • Review fix-excel-formula-errors when unexpected errors appear after upgrading Excel or sharing across locales.