The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 2, 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 kilobyte to denote 1024 bytes, conflicting with the SI definition of the prefix kilo (1000), is still common, mostly in informal computer science contexts.