Acronym for the American Standard Code for Information Interchange. Pronounced ask-ee, ASCII is a code for representing English characters as numbers, with each letter assigned a number from 0 to 127. For example, the ASCII code for uppercase M is 77. Most computers use ASCII codes to represent text, which makes it possible to transfer data from one computer to another.


Text files stored in ASCII format are sometimes called ASCII files. Text editors and word processors are usually capable of storing data in ASCII format, although ASCII format is not always the default storage format. Most data files, particularly if they contain numeric data, are not stored in ASCII format. Executable programs are never stored in ASCII format.


The standard ASCII character set uses just 7 bits for each character. A larger character set, known as extended ASCII or high ASCII, uses 8 bits, which gives it 128 additional characters.The extra characters are used to represent non-English characters, graphics symbols, and mathematical symbols. Several companies and organizations have proposed extensions for these 128 characters. The ANSI standards organization has defined a standard character set for the codes 128 through 255 (see under ANSI character set) but not all computers conform to it.


Another set of codes that is used on large IBM computers is EBCDIC.