A kibibyte (KiB) is a unit of data storage equal to 210 bytes, or 1,024 bytes. Like mebibyte (MiB) and gibibyte (GiB), kibibyte has a binary prefix to remove any ambiguity when compared to the multiple possible definitions of a kilobyte.
A kibibyte is similar in size to a kilobyte, which is 103 bytes (1,000 bytes). 1,024 kibibytes make up a mebibyte.
Due to historical naming conventions in the computer industry, which used decimal (base 10) prefixes for binary (base 2) measurements, a kilobyte could mean two different numbers depending on what was measured. Computer memory and formatted storage space used binary measurements, where one kilobyte was 1,024 bytes; disk capacity (as advertised by the manufacturer) used decimal measurements, where one kilobyte was 1,000 bytes. Since these two measurements were off by a mere 24 bytes, computer users of the day could understand the difference. Over time, storage capacities grew, and the difference between two measurements with the same names grew exponentially. Using specific binary prefixes like kibibyte and mebibyte to refer to those values helps to address the confusion.
NOTE: For a list of other units of measurement, view this Help Center article.