characterset

A characterset, also written as character set, is a defined collection of characters that a system can recognize, display, or process. Each character in the set is associated with a code point, a numeric value used by software to identify the character.

A characterset is distinct from a character encoding. The encoding is the method by which code points are translated into bytes for storage or transmission. Conversely, fonts determine how characters are visually rendered, but do not define the set of characters or their encoded representations.

Common examples include ASCII, a 7-bit set of 128 characters; ISO/IEC 8859 series and Windows-1252, which extend ASCII with 8-bit code points for various languages; and Unicode, a large, universal set designed to cover almost all written languages. While Unicode provides code points for characters, actual data interchange relies on encodings such as UTF-8, UTF-16, or UTF-32 to map those code points to bytes.

UTF-8 is the most widely used encoding on the web and is backward compatible with ASCII, using one to four bytes per code point. UTF-16 uses 2- or 4-byte units, and UTF-32 uses fixed 4-byte units. Endianness, byte order marks, and normalization can affect how encoded text is interpreted, occasionally causing mojibake when misinterpreted.

In modern computing, Unicode is commonly adopted as the character set, with UTF-8 as the preferred encoding for interoperability. Clear specification of the encoding used in files, networks, and databases remains essential to ensure correct text handling across systems.