A '''variable-width encoding''' is a type of [[character encoding]] scheme in which codes of differing lengths are used to encode a [[character set]] (a repertoire of symbols) for representation in a [[computer]]. Most common variable-width encodings are '''multibyte encodings''', which use varying numbers of [[byte]]s ([[octet (computing)|octet]]s) to encode different characters.
(Some authors, notably in Microsoft documentation, use the term ''multibyte character set,'' which is a [[misnomer]] since representation size is an attribute of the encoding, not of the character set.)
Early variable width encodings using less than a byte per character were sometimes used to pack English text into fewer bytes in [[adventure game]]s for early [[microcomputers]]. However [[disk storage|disk]]s (which unlike tapes allowed random access allowing text to be loaded on demand), increases in compsible characters; in order to encode more than 256 characters, the obvious choice would be to use two or more bytes per encoding unit, two bytes (16 bits) would allow 65,536 possible characters, but such a change would break compatibility with existing systems and therefore might not be feasible at all.
