Full-width / Half-width Converter
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Convert text between full-width (zenkaku) and half-width (hankaku) characters — for letters, numbers, symbols, spaces and katakana. It is handy for tidying up Japanese form input and data. You can choose exactly which character types to convert. Everything runs in your browser.
How to use
- Choose a direction: to half-width or to full-width.
- Tick which character types to convert (letters and numbers, spaces, katakana).
- Paste your text and copy the converted result.
How it works
Full-width Latin letters, digits and symbols sit exactly 0xFEE0 above their half-width counterparts in Unicode, so converting them is a fixed shift. Half-width katakana is mapped to full-width katakana, combining a kana with its following voiced or semi-voiced mark (for example ｶ + ﾞ becomes ガ). Hiragana and kanji are left unchanged.
Features
Both directions
Convert full-width to half-width or the other way with one toggle.
Choose what to convert
Turn conversion on or off separately for letters/numbers, spaces and katakana.
Katakana with marks
Half-width katakana with voiced marks is correctly combined into full-width kana.
Spaces too
Convert the ideographic full-width space to a normal space and back.
When to use it
Form input
Normalize names, phone numbers and codes that forms require in one width.
Data cleaning
Standardize mixed-width text in spreadsheets and CSV files.
Addresses & names
Make addresses and names consistent before saving or printing.
Fix half-width kana
Turn legacy half-width katakana into readable full-width katakana.
Notes
- Letters, numbers and symbols are converted within the ASCII range.
- Half-width katakana voiced marks are combined into single full-width kana.
- Hiragana and kanji are not affected by width conversion.
- All processing runs on your device; nothing is uploaded.
FAQ
- What are full-width and half-width characters?
- Full-width (zenkaku) characters take up the space of one CJK character, while half-width (hankaku) ones are the normal narrow Latin width. Japanese text often mixes both.
- Does it handle half-width katakana?
- Yes. Half-width katakana, including characters with voiced and semi-voiced marks, is converted to proper full-width katakana.
- Can I convert only numbers?
- Yes. Untick spaces and katakana and keep letters and numbers on to convert just the alphanumeric characters.
- Are hiragana affected?
- No. Width conversion applies to Latin characters, symbols, spaces and katakana; hiragana and kanji are left unchanged.
- Is my text sent to a server?
- No. All conversion happens locally in your browser.