Full-width / Half-width Converter
Convert between full-width and half-width characters. Handles letters, digits, symbols, spaces, and katakana with voiced marks.
Done
Full-width / Half-width Converter
How to use
- 1
Enter text
Paste the text you want to convert into the input area.
- 2
Choose a conversion
Press "To half-width" or "To full-width".
- 3
Copy
Review the result and copy it for use.
Features
- Convert full-width letters, digits and symbols to half-width and back in one click
- Converts full-width and half-width spaces
- Converts half-width katakana and full-width katakana, combining and splitting voiced marks
- Your text is never sent to a server
Use cases
Normalize data entry
Unify full-width letters and digits into half-width forms for consistent search, matching and layout.
Tidy up emails and documents
Clean up mixed full-width and half-width text before sending or publishing.
Clean up CSV data
Convert stray full-width digits or half-width katakana in exported data to match the target format.
Details
Full-width and half-width conversion rewrites full-width letters and digits (ＡＢＣ, １２３) into half-width forms (ABC, 123) and vice versa. Full-width characters occupy about twice the width of half-width ones, so conversion is used to align text and normalize data.
Besides letters, digits, symbols and spaces, this tool converts between half-width katakana (ｶﾀｶﾅ) and full-width katakana (カタカナ). Voiced and semi-voiced marks (ｶﾞ, ﾊﾟ) are combined and separated correctly, which makes the tool useful for cleaning up half-width katakana from receipts or system output.
All conversion happens in your browser - the text you enter is never sent to a server. Your original input stays untouched, so you can convert again at any time.
FAQ
What is the difference between full-width and half-width?
Full-width characters are displayed at about twice the width of half-width ones. Letters, digits, symbols and spaces come in both forms (ＡＢＣ, １２３ vs ABC, 123), and katakana does too (ｶﾀｶﾅ vs カタカナ).
Are voiced marks like ｶﾞ converted correctly?
Yes. The voiced and semi-voiced marks (ﾞ and ﾟ) are combined with the preceding character to produce the correct full-width katakana (ガ, パ). Converting the other way splits ガ into ｶﾞ.
Is Japanese text affected?
Hiragana and kanji are never converted. Only letters, digits, symbols, spaces and katakana are affected.
Is my text sent to a server?
No. All conversion happens locally in your browser. The text you enter is never transmitted.
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All processing happens in your browser. Your files are never uploaded.
Did you know?
Full-width characters are about twice as wide as half-width ones. Japanese text typically uses full-width, while Latin letters and digits use half-width.