Japanese / Text
Full-Width and Half-Width Converter (Zenkaku / Hankaku)
Convert Japanese text between full-width (zenkaku) and half-width (hankaku): letters and digits, symbols, spaces, and katakana, each on or off. For forms and cleaning data.
Full-Width and Half-Width Converter (Zenkaku / Hankaku): Full-width letters, digits, and symbols (Ａ, １, ！) become their ASCII forms and back; the ideographic space becomes a normal one. Katakana become the half-width forms of JIS X 0201, with ガ split into ｶ and ﾞ, and are joined again on the way back. Results agreed with the jaconv library on 3,000 random strings, apart from lone sound marks and ヷ ヺ, which this tool converts too. Runs 100% locally in your browser with zero server file uploads.
- Category
- Text tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Result
Half-width katakana write ガ as two characters, ｶ and ﾞ; converting to full-width joins them again. Hiragana and kanji have no half-width form and are left as they are. To keep katakana full-width while making letters and digits half-width, as many forms ask, untick Katakana.
Which characters change
Full-width forms run from ！ to ～ (U+FF01 to U+FF5E), one for each printable ASCII character, so ＡＢＣ becomes ABC and （１）becomes (1). The ideographic space U+3000 becomes a normal space. Half-width katakana run from U+FF61 to U+FF9F, along with the half-width 。「」、・ marks.
To switch between hiragana, katakana, and romaji, use the kana converter; to tidy repeated spaces afterwards, remove extra spaces.
Common settings
For a form that wants half-width numbers but full-width names, convert to half-width with Katakana unticked. To clean data copied from older systems, convert to full-width with only Katakana ticked: the half-width katakana become normal ones and the letters and digits stay as they are.
How to use it
- Paste the text.
- Choose to convert to half-width or to full-width.
- Untick what should stay as it is, such as katakana, and copy the result.
Privacy & limitations
Text is converted in your browser and never sent anywhere.
Related tools
Frequently asked questions
Why do forms ask for half-width or full-width?
Japanese systems often store numbers and addresses in one width only: many want half-width digits for phone numbers and postcodes, and full-width katakana for name readings, while bank transfers use half-width katakana.
Why does ガ become two characters?
Half-width katakana have no voiced forms, so the base ｶ and the mark ﾞ are written separately. Converting to full-width joins them back into ガ.
What about hiragana and kanji?
They exist only in full width and are left unchanged. To turn hiragana into katakana, use the kana converter.
Free tool · runs in your browser · no account required