Mebibyte

The Mebibyte (pronounced MEH-bee-byte) is a standards-based binary multiple (prefix mebi, symbol Mi) of the byte, a unit of digital information storage. Mebibyte is abbreviated MiB.

1 MiB = 2²⁰ bytes = 1,024 kibibytes = 1,048,576 bytes

The unit prefix mebi was defined by the International Electrotechnical Commission (IEC) in December 1998. Use of mebibyte and related units is endorsed by the Institute of Electrical and Electronics Engineers (IEEE) and the International Committee for Weights and Measures (CIPM) in contexts where use of a binary prefix makes sense, in order to protect the unambiguous definition of the unit prefix mega. Megabyte is sometimes used in place of mebibyte, or to refer to 10⁶ bytes = 1,000,000 bytes, or even 1,000 times 1,024 bytes, depending on context.

The historical binary interpretation of mega is still in wide use by the consumer software industry and use of the mebi prefix is still not common. This leads to consumer confusion when 2²⁰ (1,048,576) bytes is referenced as 1 MB (megabyte) instead of 1 MiB. For example, the operating system Windows XP shows a file of 2²⁰ bytes as "1.00 MB" in its file properties dialog. Likewise, a file of 10⁶ (1 000 000) bytes is reported as 976 KB. In another example, the 1.44 MB floppy disk's storage capacity is calculated using 1,024,000 bytes per "MB" (e.g. 1.44 times 1024 times 1000), rather than 1.44 mebibytes (1.44 times 1,048,576). The three size designations are similar in value.

See also

• Mebibit
• Kibibyte
• Gibibyte
• SI prefix
• IEEE 1541
• Orders of magnitude (data)

External links

• NIST Prefixes for binary multiples
• IEC Prefixes for binary multiples