On byte-oriented computers with 8 bits per byte, the 7-bit US-ASCII character set wastes 1 bit per byte, which led to hundreds of 8-bit extensions to US-ASCII. With the advent of Unicode, most of these extensions have become obsolete or obsolescent.

The ISO/IEC 8859 standards specified a series of fifteen 8-bit character sets that can be regarded as extensions of US-ASCII. (The ISO/IEC 8859 character sets are not true extensions of US-ASCII because they exclude the non-printable control characters.

ISO/IEC 8859-1, also known as Latin-1, is the most important of those 8-bit character sets. Latin-1 adds characters in support of most European languages, but does not include a symbol for the Euro currency (which did not exist when the Latin-1 character set was designed).