Single-byte and multibyte code sets

A single-byte encoding method is sufficient for representing the English character set because the number of characters is not large. To support larger alphabets, such as Japanese and Chinese, additional code sets containing multibyte encodings are necessary. All supported single-byte and multibyte code sets contain the single-byte ASCII character set. Therefore, programs that handle multibyte code sets must handle character encodings of one or more bytes.

An example of a single-byte code set is the ISO 8859 family of code sets. Examples of multibyte character sets are the IBM-eucJP and the IBM-943 code sets. The single-byte code sets have at most 256 characters and the multibyte code sets have more than 256 (without any theoretical limit).