🧾 UTF-8 Byte Encoding Basics

Why English takes 1 byte and Korean takes 3.

Convert text to hex byte values and English and Korean clearly take up different amounts of space. Here's why.

UTF-8 is a variable-length encoding

UTF-8 uses anywhere from 1 to 4 bytes per character depending on its code point. A smaller code point value (mostly Latin letters) uses fewer bytes; a larger one (Korean, emoji) uses more.

The byte ranges

Code points U+0000–U+007F (basic ASCII) use 1 byte, U+0080–U+07FF use 2 bytes, U+0800–U+FFFF (which includes precomposed Korean syllables) use 3 bytes, and U+10000 and above (most emoji) use 4 bytes.

Why this matters

Understanding UTF-8's variable length matters for calculating the actual data size sent over a network (for billing or bandwidth), and for understanding why truncating a UTF-8 string at a fixed byte boundary on an older system can cut a multi-byte Korean character in half and corrupt it.

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