The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 210, or 1024; therefore, 1 kibibyte is 1024 bytes. The unit symbol for the kibibyte is KiB.
The unit was established by the International Electrotechnical Commission (IEC) in 1998, has been accepted for use by all major standards organizations, and is part of the International System of Quantities. The kibibyte was designed to replace the kilobyte in those computer science contexts in which the term kilobyte is used to mean 1024 bytes. The interpretation of the older term "kilobyte" to denote 1024 bytes, conflicting with the SI definition of the prefix kilo (1000), is still common.
One thousand twenty-four kibibytes (1024 KiB) is equal to one mebibyte (1 MiB).
- 1 kibibyte = 210 bytes = 1024 bytes.
The prefix kibi is derived as a portmanteau of the words kilo and binary, indicating its origin in the closeness in value to the SI prefix kilo (1000). While the SI prefix is written with lowercase (k), all IEC binary prefixes start with an uppercase letter.
One byte is defined by IEC/80000-13 as 8 bits (1 B = 8 bit). Therefore 1 KiB = 8192 bit.
The kibibyte is closely related to the kilobyte. The latter term is often used in some contexts as a synonym for kibibyte, but formally refers to 103 bytes = 1000 bytes, as the prefix kilo is defined in the International System of Units.
Donald Knuth proposed to call this unit a large kilobyte (KKB). Other early proposals included using the Greek lowercase letter κ (kappa) for 1024 bytes (and using k exclusively for 1000), bK, KB, and others.
IEC binary prefixes are increasingly used, especially in scientific literature and open source software. In product advertising and other non-scientific publications, "kilobyte" sometimes refers to a power of ten and sometimes a power of two.
- International Electrotechnical Commission (2007). "Prefixes for binary multiples". Retrieved 2014-01-09.
- International Electrotechnical Commission (January 1999), IEC 60027-2 Amendment 2: Letter symbols to be used in electrical technology - Part 2: Telecommunications and electronics
- "IEC 80000-13:2008". International Organization for Standardization. Retrieved 2013-07-21.
- National Institute of Standards and Technology. "Prefixes for binary multiples". Retrieved 2015-10-09.
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- Grainger, Brian (7 August 2005). "I've got a bigger gigabyte than you!". Independent Computer Products Users Group (ICPUG). Retrieved 2007-11-15.
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