What this converter can do
- Fullwidth ↔ halfwidth for ASCII letters, numbers, and symbols.
- Hiragana ↔ Katakana and Katakana full ↔ half width.
- Optional space normalization that respects line breaks.
- Auto-converts as you type, with one-click copy for results.
Convert instantly
Clean up Japanese text
Paste text, pick a conversion type, and see the result update automatically. No data leaves your browser.
Switch between kana or width styles without reformatting the rest of your text.
Preview
Frequently asked questions
Does the text leave my browser?
No. All conversion runs locally in your browser. The text is not uploaded, added to the URL, or stored by this tool.
What does Normalize spaces do?
Before the selected conversion, it changes tabs, non-breaking spaces, and fullwidth spaces to ordinary spaces and collapses consecutive spaces on each line to one. It keeps the number of line breaks and does not remove a single leading or trailing space. A later fullwidth conversion may change the remaining spaces to fullwidth.
What is the difference between kana conversion and width conversion?
Kana conversion changes Hiragana and Katakana script. Width conversion changes only characters that have fullwidth and halfwidth forms, such as ASCII letters, numbers, symbols, spaces, and Katakana. The operations are independent.
Can I convert only numbers or only Katakana?
Yes. Choose Custom width conversion, select the direction, and enable only the character types you want to change. Unselected characters pass through unchanged.
What happens to Katakana without an exact halfwidth form?
They are left unchanged and a warning is shown. The converter never substitutes a similar but different character. For example, ヵ and ヶ remain unchanged, while ヷ and ヺ can be represented exactly as ﾜﾞ and ｦﾞ.
How can I avoid breaking CSV or TSV data?
Test a small sample first and confirm delimiters, quotes, spaces, and line breaks. Symbols change only when their category or an ASCII width mode is selected, and the converter preserves the number of line breaks.