EBCDIC (Extended Binary Coded Decimal Interchange Code) is a binary coding scheme developed by International Business Machines (IBM) Corporation for the operating systems within its larger computers. EBCDIC is a method of assigning binary number values to characters (alphabetic, numeric, and special characters such as punctuation and control characters). In the early 1960s IBM adapted EBCDIC from punched-card code. EBCDIC was the code for text files used in IBM's OS/390 operating system for its S/390 servers, and continues to be used by corporations for their legacy applications and data (those that have been inherited earlier generations of technology).

EBCDIC is functionally similar to the ASCII (American Standard Code for Information Interchange) coding scheme that is widely used with smaller computers. However, IBM's PC and workstation operating systems do not use EBCDIC but the industry-standard ASCII code. Conversion programs permit different operating systems to change a file back and forth between EBCDIC and ASCII.

In an EBCDIC file, each character is represented by an 8-bit binary number (a byte), thus allowing for the encoding of 2⁸ = 256 possible characters. This is in contrast to the 7-bit binary number (128 possible characters) used in the standard ASCII format. Although EBCDIC is not widely used with personal computers, it is well-known and internationally recognized, primarily as an IBM code for the corporation's mainframes and minicomputers. EBCDIC currently exists in at least six mutually incompatible versions. Although most characters are the same in ASCII and EBCDIC, some ASCII characters do not exist in EBCDIC (e.g., square brackets--[]) and EBCDIC contains some characters (e.g., the "cent" sign--¢--and the "not" sign--¬) that are not in ASCII.