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ASC Function
Summary
The Excel ASC function converts full-width (double-byte) Japanese characters to half-width (single-byte) equivalents for DBCS languages. This is essential for data standardization and compatibility in Japanese Excel environments.
Syntax
ASC(text)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| text | Text |
Yes | The text or a reference to a cell containing the text you want to change. If text does not contain any full-width letters, it remains unchanged. |
Using the ASC Function
ASC is primarily used in Japanese versions of Excel where full-width characters are common. It standardizes text data by converting full-width characters (like full-width A「Ａ」to half-width A「A」), making data more compatible with systems expecting standard ASCII characters.
Common ASC Examples
Basic Full-width to Half-width Conversion
=ASC("ＥＸＣＥＬ")Converts full-width "ＥＸＣＥＬ" to standard half-width "EXCEL".
Mixed Text Handling
=ASC("EXCEL２０２４")Converts full-width numbers "２０２４" to "2024" while keeping "EXCEL" unchanged.
No Change for Standard Text
=ASC("EXCEL")Returns "EXCEL" unchanged since it contains no full-width characters.
Frequently Asked Questions
Common Errors and Solutions
#VALUE! error
Cause: Invalid text reference or non-text argument
Solution: Ensure the text parameter contains or references valid text data.
Notes
- ASC only affects full-width characters; standard ASCII remains unchanged.
- Common in Japanese business applications for data normalization.
- Full-width characters often appear as slightly wider versions of standard letters/numbers.
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003 and earlier versions
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+