Half / Full Width Converter

Input

Mode

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Result

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All processing happens in your browser — your files are never uploaded to a server.

About this Tool

AllThatConverter's half-width / full-width converter is a free online tool that interconverts half-width and full-width characters — katakana, alphanumerics, and symbols — commonly needed in Japanese text processing. It is ideal for database normalization, content editing, and form input standardization. All processing runs locally in your browser with no uploads. No registration required, completely free.

100% Secure Local Processing Active

This tool runs entirely on your device via WebAssembly and browser Canvas. No files are ever sent to any remote server, ensuring complete data security.

How to Use

1

Paste the text you want to convert into the input area.

2

Click 'Half-Width → Full-Width' or 'Full-Width → Half-Width'.

3

The converted text appears instantly in the output area.

4

Click 'Copy' to copy the result.

Half/Full-Width Converter Use Cases

Database and Form Data Normalization

Normalize mixed half-width and full-width katakana or alphanumerics entered by users to a uniform format before storing in a database.

Japanese Content Creation and Editing

Standardize half-width/full-width character usage across web content or print materials in one batch operation.

E-Commerce Product Data Cleanup

Unify product names and descriptions by converting alphanumeric characters and symbols to a consistent width for better search accuracy.

Legacy System Data Migration

Resolve character-width mismatches when migrating data between legacy systems and modern systems with different character-encoding conventions.

Half/Full-Width Converter FAQ

Half-width katakana (e.g. アイウ) are single-byte legacy characters; full-width katakana (e.g. アイウ) are multibyte Unicode characters. Modern systems recommend full-width katakana.

Yes. Latin letters (A–Z, a–z), digits (0–9), and common symbols are converted between their half-width and full-width forms.

No. All processing runs locally in your browser. Nothing is transmitted or saved externally.

Standard half-width hiragana does not exist in Unicode, so hiragana conversion is not supported. The tool focuses on katakana and alphanumeric half/full-width conversion.

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