UTF-8 to UTF-16 Converter
Re-encode UTF-8 text or files as UTF-16. 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 UTF-16
What Windows Notepad calls "Unicode", and what SQL Server and some Excel exports emit. Each character takes two bytes (four for emoji).
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. UTF-16 has two byte orders (LE / BE) distinguished by a BOM (FF FE / FE FF). Without a BOM, the position of NUL bytes gives it away. The tool decodes the input bytes to Unicode and re-encodes them as UTF-16, 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 UTF-16?
UTF-16 covers all of Unicode, so nothing readable in UTF-8 is lost. Just make sure the source encoding is right — a wrong guess produces mojibake.
Should I add a BOM?
Yes, for UTF-16 a BOM is recommended because it is what identifies the byte order (LE or BE).
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.