Full/Half-width Converter

Convert Katakana, alphabets, and numbers between full-width and half-width.

Target Character Types:
Conversion Direction:

Zenkaku ↔ Hankaku Converter — Full-Width & Half-Width Alphanumeric / Katakana

When filling out Japanese e-commerce checkouts, shipping addresses, hotel bookings or banking forms, you will often run into validation errors demanding either "Full-width characters (全角 / Zenkaku)" or "Half-width alphanumeric characters (半角英数字 / Hankaku)". Even though full-width (ＡＢＣ１２３) and half-width (ABC123) look like the same letters, computers treat them as completely different Unicode code points. Convert Katakana (カタカナ ↔ ｶﾀｶﾅ), Latin letters, digits, spaces and punctuation between full-width and half-width in a single click.

How to use it

  1. Paste your Japanese address, name (Katakana), phone number or text into the input box.
  2. Select Full-width to Half-width (Zenkaku → Hankaku) or Half-width to Full-width (Hankaku → Zenkaku).
  3. Toggle which character classes to convert (alphanumeric letters/numbers, Katakana, symbols/spaces) and copy the output.

Frequently asked questions

What does "enter half-width alphanumeric characters (半角英数字)" mean on Japanese websites?
Half-width alphanumeric characters (Hankaku Eisuuji) are standard ASCII Latin letters (A–Z, a–z) and digits (0–9) like "ABC123". If your Japanese IME accidentally typed full-width letters like "ＡＢＣ１２３", the form will reject them until you convert them to half-width.
When do Japanese forms require full-width (Zenkaku) characters?
Most Japanese forms require full-width Katakana (全角カナ) for phonetic names (Furigana) and sometimes require full-width numbers and hyphens (e.g., １−２−３) inside the street address block (Chome/Banchi).
Does converting half-width Katakana combine voiced marks (dakuten ゛ and handakuten ゜)?
Yes. Half-width Katakana stores voiced marks as separate characters (such as ｶﾞ), and this converter automatically merges them into proper single full-width characters (ガ).