Fullwidth to Halfwidth Converter Online
Convert fullwidth characters to halfwidth online in one click: which characters change, why Chinese text stays untouched, and how to fix code, URLs, and data.
Chinese input methods default to fullwidth punctuation, which becomes a compile error when pasted into code; fullwidth digits in a spreadsheet break lookups; fullwidth parentheses in a URL make the request fail. The fullwidth/halfwidth converter fixes these in one click. It converts in both directions, covering letters, digits, punctuation, and spaces, entirely in your browser. We tested mixed Chinese text with fullwidth punctuation and digits in both directions before writing this guide.
What is the difference between fullwidth and halfwidth?
Halfwidth characters take one standard character width and are the normal form of ASCII letters, digits, and punctuation. Fullwidth characters take two halfwidth widths and are common in Chinese and Japanese typesetting and input methods. Both spellings of the same characters are valid, but programs usually accept only one:
| Halfwidth | Fullwidth |
|---|---|
a | ａ |
1 | １ |
, | ， |
( ) | （ ） |
| Space | Fullwidth space |
Fullwidth characters live in their own Unicode block (Halfwidth and Fullwidth Forms, U+FF00–FFEF); see the Unicode code chart.
When do you need to convert to halfwidth?
The three most common situations:
- Writing code and configuration files: fullwidth punctuation in strings, identifiers, or comments can cause syntax errors or unexpected behavior.
- URLs and paths: browsers do not treat fullwidth characters as halfwidth equivalents, so copied-and-pasted requests may fail.
- Data processing: fullwidth digits or letters mixed into data break queries and matching; normalize character width first.
Conversion only touches letters, digits, punctuation, and spaces. Chinese characters have no fullwidth/halfwidth distinction and are never affected.
How to convert with the tool
- Open the fullwidth/halfwidth converter, then paste or type text.
- Click "To halfwidth" to restore fullwidth characters; use "To fullwidth" when you need the reverse.
- Copy the result and replace the original text.
Halfwidth-to-fullwidth covers ASCII printable characters (space through tilde); fullwidth-to-halfwidth covers the matching fullwidth characters and fullwidth spaces. After normalizing widths, you can continue with the case converter to align naming style, or the text deduplicator to clean up data.
Frequently asked questions
Can fullwidth punctuation be converted to halfwidth?
Yes. "To halfwidth" converts fullwidth letters, digits, punctuation, and fullwidth spaces to their halfwidth forms.
Does conversion affect Chinese characters?
No. Chinese characters have no fullwidth/halfwidth distinction; conversion only touches letters, digits, punctuation, and spaces.
Is my text uploaded?
No. All processing happens locally in your browser; input is never sent to any server.
Convert a real snippet now
Paste the code fragment that fails or the data that will not match into the fullwidth/halfwidth converter, click "To halfwidth" once, and diff the result. Fullwidth issues are usually not logic errors — they are inconsistent character widths, and normalizing first makes debugging much faster.
References
[1] Unicode — Halfwidth and Fullwidth Forms (U+FF00–FFEF): https://www.unicode.org/charts/PDF/UFF00.pdf