Codepoint

A code point is a numeric value that uniquely identifies a character in a character set or encoding system. In Unicode, code points are abstract identifiers for characters and are typically written as a value with the prefix U+, followed by hexadecimal digits. For example, U+0041 designates the Latin capital letter A, and U+1F600 designates the grinning face emoji. A code point is not the character itself and not a specific byte sequence; it is an abstract reference used by software to identify a character.

Code points are mapped to bytes by encodings. Unicode defines several encoding forms, such as UTF-8, UTF-16, and UTF-32, which specify how code points are represented in storage or transmission. For instance, the code point U+0041 is encoded as the single byte 0x41 in UTF-8, as 0x0041 in UTF-16, and as 0x00000041 in UTF-32. The encoding form determines the number of bytes and their arrangement, while the code point remains the universal identifier for the character.

Unicode assigns code points in the range U+0000 to U+10FFFF, organized into planes, with the Basic Multilingual Plane spanning U+0000 to U+FFFF and supplementary planes from U+10000 to U+10FFFF. Some ranges are reserved for private use, and the surrogate pair range U+D800 to U+DFFF is used in UTF-16 encoding and is not assigned to characters itself. Certain code points are non-characters or reserved for internal use.

Code points are distinct from glyphs—the shapes produced by fonts. A single code point may render differently across fonts, and multiple code points can combine to form a single visual symbol. They are central to text processing, storage, search, and normalization in modern computing.