Convert alphanumeric & katakana between full-width ⇔ half-width
Using the full-width/half-width converter is very simple:
Full-width/half-width conversion is essential for text processing in Japanese environments:
When registering customer information or product data in databases where half-width alphanumeric characters are preferred, you can batch convert full-width input data to half-width. Example: '０１２３' → '0123'
Useful for unifying alphanumeric notation in business documents and reports. Convert full-width alphanumeric to half-width or vice versa.
Useful for debugging and fixing when full-width characters get mixed into source code or data files. Unify variable names and file names to half-width.
Unify text mixing full-width and half-width katakana. Example: 'ｶﾀｶﾅ' → 'カタカナ', or reverse conversion.
For forms requiring half-width input like postal codes, phone numbers, email addresses, convert full-width input data to half-width for correct submission.
Convert queries to unified format to prevent search misses due to full-width/half-width differences in search engines and database searches.
Full-width and half-width characters are concepts specific to Japanese environments that represent differences in character display width.
Characters displayed in a width that fits in a square frame. Mainly includes Japanese (kanji, hiragana, katakana) and full-width alphanumeric characters.
Example: 'ＡＢＣ１２３カタカナ' (full-width)
Characters displayed at half the width of full-width characters. Mainly includes half-width alphanumeric, half-width katakana, and half-width symbols.
Example: 'ABC123ｶﾀｶﾅ' (half-width)
Mutually converts full-width alphanumeric (ＡＢＣ１２３) and half-width alphanumeric (ABC123).
Mutually converts full-width katakana (カタカナ) and half-width katakana (ｶﾀｶﾅ). Dakuten and handakuten marks are correctly processed.
Mutually converts full-width symbols (！？「」) and half-width symbols (!?"").
Mutually converts full-width space ( ) and half-width space ( ).
Note: Hiragana and kanji only exist in full-width, so they are not converted.
By unifying to half-width before registering customer information, product codes, etc. in databases, searches and aggregations become more accurate.
When full-width character contamination is the cause of errors, you can batch convert and fix with this tool.
For forms requiring half-width input, you can pre-convert data entered in full-width before copy & paste.
Multi-line text can also be converted at once, enabling efficient formatting of large amounts of data.
Full-width characters are displayed in a width that fits in a square frame, while half-width characters are displayed at half that width. They are mainly differentiated in Japanese environments.
Alphanumeric (A-Z, a-z, 0-9), katakana, symbols, and spaces can be converted. Hiragana and kanji only exist in full-width so they cannot be converted.
Generally, full-width katakana is recommended. Half-width katakana has a risk of character corruption and should be avoided in business documents. However, some systems and legacy data may use half-width katakana.
In source code, basically only use half-width alphanumeric and symbols. Full-width character contamination causes errors. Variable names, function names, operators, etc. must be written in half-width.
It depends on database settings. In many cases, full-width and half-width are distinguished, so it's recommended to convert data to a unified format before searching.
Yes, multi-line text including line breaks can be converted all at once.
Yes, you can copy directly from the conversion result text box. One-click copy is also possible with the 'Copy' button.
All conversion processing is done in your browser and input data is not sent to the server. You can use it with confidence.
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