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Full width half width converter

Paste text, choose full width to half width or the reverse, and review a separate result before copying. The conversion runs locally in your browser tab.

Direction Convert kana too

ASCII letters, numbers, symbols, and ordinary spaces are always handled. Kana is optional.

0 characters 0 UTF-8 bytes 1 lines 0 result characters

InputNot run

Converted resultNot run

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Read these Sakura Editor setup, macro, and regex notes before or after testing text workflows in the browser.

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What the full width half width converter does

This full width half width converter changes the display width of pasted text without overwriting the original input. It converts full width and half width Latin letters, numbers, ASCII punctuation, and ordinary spaces in either direction. That is useful when an ID, address, CSV field, or search value looks correct but fails an exact match because visually similar characters are different code points.

Kana conversion is a separate option because half width katakana can be meaningful in older Japanese systems and data exports. Leave the option off when only ASCII and spaces need normalization. The result stays in its own pane so you can compare the beginning, middle, and end before copying it into an editor or form.

How to use the full width half width converter

Paste a copyKeep the original file or message unchanged and paste a representative sample into the input pane.
Choose a directionSelect full width to half width or half width to full width.
Decide on kanaEnable kana conversion only when katakana width is part of the task.
Review and copyCheck punctuation, spaces, line counts, and the final lines before copying the result.

Supported characters and boundaries

The tool changes character width; it does not detect the original file encoding, translate text, or rewrite unrelated characters. Use the table as a quick boundary check before applying the result.

Input area	Behavior	Review point
Letters and numbers	Convert full width and half width forms	Check IDs, phone numbers, and model codes
ASCII punctuation	Convert matching width forms	Check email addresses, URLs, and delimiters
Spaces	Convert full width and ordinary spaces	Search for invisible differences
Katakana	Convert only when the checkbox is enabled	Review voiced marks and proper names
Kanji and hiragana	Keep the characters as entered	Character type is not changed

Examples: full width to half width and back

A string such as `Ａ-１２３４` may look readable but still fail a database lookup or form validation that expects half width ASCII. Convert it to `A-1234`, then test the value in the destination system. The same check matters for punctuation in email addresses and URLs, where a full width symbol is not interchangeable with its ASCII form.

The reverse direction is useful for a report or Japanese input rule that expects consistent full width letters and numbers. The converter does not know the rule of the receiving service, so the final validation belongs to that service or to the desktop application where the text will be saved.

Example input	Direction	Expected shape
Ａ１２３	Full width → half width	A123
A123	Half width → full width	Ａ１２３
text	Full width → half width	text
ｶﾀｶﾅ	Half width → full width + kana	カタカナ

When conversion appears not to work

First check whether the input actually contains a width difference. Kanji and hiragana are outside the width conversion scope, and converting already-half-width ASCII to half width produces no visible change. If the result is empty, paste text into the input pane and run the conversion again.

A keyboard full-width/half-width key changes an input method state; it does not normalize a multi-line block that has already been pasted. For a large document, test a short sample here and then repeat the decision in Sakura Editor or the destination application with a copy of the file.

Browser conversion versus Sakura Editor files

The online tool is designed for pasted text and one-off normalization. It does not preserve an unknown source encoding, update a file on disk, search multiple files, or reproduce every Sakura Editor regular-expression and save option. UTF-8, Shift_JIS, BOM, and line-ending checks are separate tasks.

Before saving a converted result, inspect representative sections and compare the result with the original. The site's character counter, Tab and spaces converter, regex tester, and character-encoding guide can help with nearby checks, but the final file should be opened and tested in the application that will use it.

Frequently asked questions

Can I convert full width characters to half width?

Yes. Choose Full width → half width, paste your text, and run the converter. Full width ASCII letters, numbers, punctuation, and spaces are handled.

Can I convert half width characters to full width?

Yes. Choose Half width → full width. The result is shown separately so you can inspect it before copying.

Can the converter handle half width katakana?

Enable Convert kana too when katakana width is part of the task. Review voiced and semi-voiced marks and names after conversion.

Does the full width half width converter upload my text?

The conversion runs in browser JavaScript and the tool does not send the input to a processing server. Your browser, extensions, clipboard, and workplace policy still matter.

Will this fix an encoding or mojibake problem?

No. It changes character width after text is pasted. File encoding, Shift_JIS, BOM, and mojibake need a separate diagnosis and save check.

Can I use the tool on a phone?

Yes for moderate text in a current mobile browser. A desktop is easier for long files and detailed side-by-side review.