MBMiB

MBiB is a nonstandard data-storage unit that has appeared in some software and documentation to denote the mebibyte, a binary unit of digital information. A mebibyte (MiB) equals 2^20 bytes, or 1,048,576 bytes. MBiB is not part of the official prefix system; the accepted abbreviation for this size is MiB.

Because MBiB is not an officially recognized term, its use can lead to confusion with MB, the decimal megabyte defined as 1,000,000 bytes. The lack of a consistent definition means MBiB can be interpreted differently depending on context, which undermines precision in descriptions of storage capacity or memory.

In practice, MBiB has appeared in various historical contexts, including some firmware notes, technical documents, or legacy software where informal shorthand was used. Modern documentation typically avoids MBiB in favor of MiB to prevent ambiguity, and many software tools display sizes using MiB or, less commonly, MB (for decimal) depending on the setting.

Conversions help illustrate the distinction: 1 MBiB equals 1 MiB, which is 1,048,576 bytes. By comparison, 1 MB (decimal) equals 1,000,000 bytes. As a result, 1 MBiB is about 4.3% larger than 1 MB. For clear communication, it is recommended to use MiB when referring to binary-based sizes and MB for decimal-based sizes, and to avoid MBiB altogether.