UTF-8 to Shift_JIS Converter
Re-encode UTF-8 text or files as Shift_JIS. Paste text or pick a file, check the preview, then download. Everything runs inside your browser, so confidential documents never leave your device.
About UTF-8
The de-facto standard for the web, source code and data interchange. It covers every script plus emoji, and is byte-compatible with ASCII.
About Shift_JIS
The long-standing Japanese encoding on Windows. Still produced by Excel CSV exports and legacy business systems. The Windows variant is called CP932 (MS932) and adds vendor-specific characters.
How the conversion works
UTF-8 is a 1–4 byte variable-width encoding. A BOM is optional, but adding one keeps Excel from garbling CSV files. Shift_JIS is a 1–2 byte variable-width encoding; half-width kana fit in a single byte. It cannot represent emoji or some rarer kanji. The tool decodes the input bytes to Unicode and re-encodes them as Shift_JIS, warning you about any byte or character that could not be represented.
How to use it
1) Paste your text or choose a file. 2) Toggle the BOM option if you need one. 3) Press Convert to preview and download the result. Files are also run through encoding detection so you can confirm the source encoding was right.
Frequently asked questions
Is my file uploaded anywhere?
No. All processing happens in JavaScript inside your browser; the file contents never touch the network. The page keeps working offline once loaded.
Can characters be lost converting UTF-8 to Shift_JIS?
Shift_JIS has a limited repertoire, so emoji and some rare characters cannot be represented and become "?". The tool lists every character it could not map.
Should I add a BOM?
Shift_JIS has no BOM convention, so none is written.
Is there a file size limit?
There is no server-side limit. Anything your browser can hold in memory — tens of megabytes in practice — will convert, though very large files may take a few seconds.