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Full-Width to Half-Width Converter

Convert zenkaku full-width letters, digits and katakana to hankaku half-width and back, with dakuten composition and an NFKC normalisation mode.

Result

Paste full-width or half-width text above to convert it. Half-width katakana with a dakuten (ｶ + ﾞ) is composed into a single character (ガ) and back again.

What is the Full-Width to Half-Width Converter?

Japanese and Chinese input methods produce full-width (zenkaku) characters that occupy the same square as a kanji: Ｈｅｌｌｏ instead of Hello, １２３ instead of 123.

  • Zenkaku to hankaku and hankaku to zenkaku in one tool
  • Composes ｶ + ﾞ into ガ and ﾊ + ﾟ into パ, and decomposes them again
  • Handles the ideographic space U+3000 and full-width punctuation
  • Separate NFKC mode for comparing against Unicode compatibility folding
  • Counts how many character positions actually changed
  • Copy or download the result; nothing is uploaded

How to use the Full-Width to Half-Width Converter

  1. 1

    Paste your full-width or half-width text into the input box.

  2. 2

    Pick a conversion: full-width to half-width, half-width to full-width, or Unicode NFKC normalisation.

  3. 3

    Check the stat tiles for how many characters went in, came out and actually changed.

  4. 4

    Copy the converted text or download it as a .txt file.

About the Full-Width to Half-Width Converter

Japanese and Chinese input methods produce full-width (zenkaku) characters that occupy the same square as a kanji: Ｈｅｌｌｏ instead of Hello, １２３ instead of 123. They break search, sorting and validation everywhere else, so they usually need converting to half-width (hankaku) forms.

This converter works by code-point arithmetic: U+FF01–U+FF5E shift down by 0xFEE0 to their ASCII equivalents and the ideographic space U+3000 becomes a normal space. Half-width katakana is handled properly too — ｶ followed by the voicing mark ﾞ composes into the single character ガ, and the reverse direction splits it back apart. A third mode applies Unicode NFKC normalisation so you can compare a strict width conversion against the broader compatibility fold.

Conversion happens entirely in your browser. Your text is never uploaded, which matters when you are cleaning up customer records or address data, and the tool works offline once the page has loaded.

Frequently asked questions

What is the difference between zenkaku and hankaku?

Zenkaku means full-width: the character occupies a full square cell, the same as a kanji. Hankaku means half-width: the character takes half that space, like normal ASCII. They are different Unicode code points even when they look like the same letter.

How do I convert full-width numbers to normal numbers?

Paste them in and choose “Full-width to half-width”. Full-width digits live at U+FF10 to U+FF19, exactly 0xFEE0 above ASCII 0-9, so the conversion is exact and reversible.

Does this handle half-width katakana with dakuten?

Yes. Half-width katakana writes the voicing mark as a separate character, so ｶﾞ is two code points. Converting to full-width composes them into the single character ガ, and converting back splits them apart again.

Should I use NFKC normalisation instead?

NFKC does everything a width conversion does and more — it also folds ligatures like fi, superscripts and circled letters into plain text. Use NFKC if you want maximum normalisation, and the width conversion if you only want to change character widths and leave everything else alone.

Is my text sent to a server?

No. The conversion is pure JavaScript running in your browser, so your text stays on your device and the tool keeps working without an internet connection.

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