Fullwidth ⇄ Halfwidth converter — alphanumerics, kana, symbols
Convert between fullwidth ASCII (letters, digits, symbols) and halfwidth ASCII with a single mode toggle. Covers U+FF01–U+FF5E ⇄ U+0021–U+007E, plus the ideographic space U+3000 ⇄ ASCII space U+0020. Hiragana, katakana, and kanji are kept untouched. Runs entirely in your browser.
How to use
Paste text, choose a direction (Fullwidth → Halfwidth or Halfwidth → Fullwidth), then click Run. Fullwidth → Halfwidth maps U+FF01–U+FF5E down to U+0021–U+007E and U+3000 to U+0020. Halfwidth → Fullwidth performs the reverse shift. Katakana, hiragana, kanji, emoji, newlines, and tabs are out of scope and pass through unchanged. Copy the result or download as .txt.
FAQ
- Is text uploaded?
- No. This is a pure code-point arithmetic with no network calls — input and output stay inside your browser.
- What range is covered?
- Fullwidth ASCII (U+FF01–U+FF5E) ↔ printable ASCII (U+0021–U+007E), plus the ideographic space U+3000 ↔ ASCII space U+0020 — 95 characters in each direction.
- Does it touch katakana?
- No. Only the ASCII range is in scope. Fullwidth katakana stays fullwidth, and halfwidth katakana (ｦｱｲｳ…) is never created or normalized here.
- What about newlines and tabs?
- Newlines (\n) and tabs (\t) are out of scope and are preserved as-is. Only printable characters and spaces visibly change width.
- What happens when I switch modes?
- The mode is evaluated at conversion time, so after toggling the radio you need to click Run again to recompute. The stats row beneath the output also shows the active direction.
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