Half / Full Width Converter
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.
Processed safely on your device
Everything happens in your browser on this device. Your files are never sent to our servers—so you can use it with peace of mind.
How to Use
Paste the text you want to convert into the input area.
Click 'Half-Width → Full-Width' or 'Full-Width → Half-Width'.
The converted text appears instantly in the output area.
Click 'Copy' to copy the result.
Key Scenarios & 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.
Frequently Asked Questions (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.