UTF-8 Encoder

Convert Unicode text into its UTF-8 byte sequence and view the resulting byte values in hex or decimal.

UTF-8 Encoder

Convert text to UTF-8 byte array representation (decimal values).

Input Text

UTF-8 Bytes (Decimal)

About UTF-8 Encoding

UTF-8 encoding shows how JavaScript strings are represented as bytes internally.

Common use cases:

Understanding string byte sizes for APIs
Debugging character encoding issues
Working with binary protocols
File size calculations for text data

Note: Each number represents one byte (0-255). Unicode characters may use multiple bytes.

What is UTF-8 Encoding?

UTF-8 is a variable-width character encoding that represents every Unicode code point using one to four bytes. ASCII characters (U+0000–U+007F) map to a single byte identical to their ASCII value, making UTF-8 fully backward-compatible with ASCII. Characters outside that range use multi-byte sequences with specific bit patterns that allow decoders to identify boundaries unambiguously.

UTF-8 is the dominant encoding for text on the web, in databases, and in source code, and is the default encoding for JSON, HTML5, and XML.

Common Use Cases

Internationalisation (i18n): Encode multilingual text — Arabic, Chinese, emoji, and more — into bytes that can be stored and transmitted uniformly. Network Protocol Implementation: Construct byte-level payloads for protocols (e.g., WebSocket, HTTP/2) that require UTF-8 encoded strings. File I/O: Confirm the byte sequence written to disk when saving text files to ensure correct encoding rather than relying on system defaults. Cryptographic Input Preparation: Hash functions and MACs operate on bytes; UTF-8 encoding provides a canonical byte representation of text input.

Tips

Always specify UTF-8 explicitly when opening files or making network requests — never rely on the operating system's locale default encoding. A single Unicode code point (e.g., an emoji) may occupy 4 bytes in UTF-8; string length in characters and length in bytes are not the same. The UTF-8 BOM (EF BB BF) is optional and generally discouraged; omit it unless a specific tool or legacy system requires it.