Full-width ↔ Half-width Converter (Zenkaku / Hankaku)
Convert between full-width (全角) and half-width (半角) Japanese & Latin characters
How it works
In Japanese typography, Latin letters, digits and katakana exist in both full-width (zenkaku, occupying a full em square) and half-width (hankaku) forms. This converter maps ASCII to its full-width range and back, and converts half-width katakana (ｱｲｳ) to and from full-width katakana (アイウ). It also converts between hiragana and katakana. These conversions are essential when normalizing user input before storing, searching or comparing Japanese text — for example, unifying ﾊﾝｶｸ and ハンカク so they match.
Frequently asked
What are zenkaku (全角) and hankaku (半角)?
Zenkaku are full-width characters that occupy one em square; hankaku are half-width. The same letter or katakana can appear in either form, and Japanese systems often normalize one to the other before storage or comparison.
Does it convert half-width katakana?
Yes. Half-width katakana like ｱｲｳ (hankaku) convert to full-width アイウ (zenkaku) and back, alongside ASCII letters, digits and punctuation.
Can it convert hiragana to katakana?
Yes — use the Hiragana → Katakana and Katakana → Hiragana modes to switch between the two kana scripts (ひらがな ⇄ カタカナ).
Why normalize full-width and half-width text?
Mixed widths cause string comparisons and searches to fail (e.g. ABC vs ＡＢＣ, or ﾊﾝｶｸ vs ハンカク). Normalizing to a single width makes data consistent and searchable.