UTF-8 to UTF-16 Converter: Unicode Encoding Tool

Convert text between UTF-8 and UTF-16 encodings with byte-level visibility. Choose between little-endian and big-endian for UTF-16. Essential for Windows development, Java applications, and cross-platform data exchange.

Byte Order (Endianness)

BE: Most significant byte first | LE: Least significant byte first

Output Format

UTF-8 Text

UTF-8 vs UTF-16

UTF-8 and UTF-16 are both Unicode encoding forms. UTF-8 uses 1-4 bytes per character and is backward compatible with ASCII. UTF-16 uses 2 or 4 bytes and is commonly used in Windows and Java.

UTF-8

1-4 bytes per character
ASCII compatible
Web standard
Variable length

UTF-16

2 or 4 bytes per character
Used in Windows, Java
Endianness matters
May include BOM

Example: "A" = 00 41 (UTF-16 BE) | 41 (UTF-8)

How it works

This tool converts text between UTF-8 and UTF-16 encodings. Both are Unicode transformation formats that represent the same characters using different byte sequences.

UTF-8 uses 1-4 bytes per character, with ASCII characters staying as single bytes. UTF-16 uses 2 or 4 bytes, with common characters in the Basic Multilingual Plane using exactly 2 bytes. The converter reads the input encoding and transforms each character to the target encoding's byte representation.

Encoding comparison:

AUTF-8: 0x41, UTF-16: 0x0041

€UTF-8: 0xE2 0x82 0xAC, UTF-16: 0x20AC

Paste text in either encoding and select the conversion direction. The tool shows the byte representation and converted output instantly.

When you'd actually use this

Debugging cross-platform text issues

A developer sees garbled text when moving data between Windows (often UTF-16) and Linux (typically UTF-8). They convert between encodings to identify where the corruption occurs in the pipeline.

Working with Windows API functions

A programmer calls Windows APIs that expect UTF-16 wide strings. They convert UTF-8 input from their cross-platform code to UTF-16 before passing to Windows functions like CreateFileW.

Processing Java string data

Java uses UTF-16 internally for strings. A developer working with Java native interfaces converts between UTF-8 (from C/C++ code) and UTF-16 (Java strings) for proper text handling.

Analyzing binary file formats

A reverse engineer examines a file format that stores strings in UTF-16. They convert the hex dump to readable text by interpreting the bytes as UTF-16 and converting to UTF-8 for display.

Fixing database encoding mismatches

A DBA discovers a column stores UTF-16 data but the application expects UTF-8. They convert existing data to match the application's encoding before fixing the schema definition.

Testing internationalization code

A QA engineer tests whether their app handles encoding conversions correctly. They generate test strings with various Unicode characters and verify UTF-8 to UTF-16 conversion preserves all characters.

What to know before using it

UTF-8 and UTF-16 represent the same characters.This isn't a character conversion—it's a byte representation change. The visible text stays identical. Only the underlying bytes differ.

Byte order matters for UTF-16.UTF-16 can be big-endian (UTF-16BE) or little-endian (UTF-16LE). Windows typically uses little-endian. This tool handles both but you need to know which your system expects.

UTF-8 is more space-efficient for ASCII.English text takes half the space in UTF-8 versus UTF-16. For primarily ASCII content, UTF-8 is the better choice.

Some characters need 4 bytes in both encodings.Emoji and rare CJK characters outside the Basic Multilingual Plane require 4 bytes in UTF-16 (as surrogate pairs) and 4 bytes in UTF-8.

Pro tip: When debugging encoding issues, look at the raw hex bytes. UTF-8 ASCII is 00-7F. UTF-16 has null bytes between ASCII characters (41 00 42 00 for "AB" in little-endian). This pattern helps identify the encoding quickly.

Common questions

Which encoding should I use?

For web, APIs, and Unix systems, use UTF-8. It's the standard. For Windows APIs and Java internals, you'll encounter UTF-16. When you control the format, prefer UTF-8 for compatibility.

Why does UTF-16 text look weird in a hex editor?

UTF-16 stores each 16-bit code unit as two bytes. ASCII text like "Hello" appears as "H\0e\0l\0l\0o\0" with null bytes between characters. This is normal for UTF-16.

What's a byte order mark (BOM)?

A BOM is a special character (U+FEFF) at the start of a file that indicates the encoding and byte order. UTF-8 doesn't need one but may have it. UTF-16 uses it to signal big or little endian.

Can I convert any text between these encodings?

Yes, any valid Unicode text converts between UTF-8 and UTF-16 without loss. Both encodings support the full Unicode range. Invalid byte sequences will fail conversion.

Why is my UTF-16 file twice as large?

For ASCII-heavy text, UTF-16 uses 2 bytes per character while UTF-8 uses 1 byte. Your file size roughly doubles. For non-ASCII text, the difference shrinks as UTF-8 needs more bytes too.

How do I know if UTF-16 is big or little endian?

Check the BOM at the start: FE FF means big-endian, FF FE means little-endian. Without a BOM, you need to know the source system. Windows uses little-endian, network protocols often use big-endian.

Does this work with emoji?

Yes, emoji convert correctly. They use 4 bytes in both encodings. In UTF-16, they appear as surrogate pairs—two 16-bit values that together represent one character.

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