Megabait

Megabait is an informal, nonstandard unit of data storage that is occasionally encountered in older texts or in non-English contexts. It is not defined by international standards bodies, and modern technical writing generally avoids it. When it appears, it is usually intended as a rough synonym for a megabyte (MB), or, less commonly, for a mebibyte, depending on context; this makes it ambiguous.

In decimal terms, if used as a decimal megabait, it would equal 1,000,000 bytes. In binary terms, some contexts assign 1,048,576 bytes, the size of a mebibyte. However, mebibyte is the proper name for 1,048,576 bytes, and MB is preferred for 1,000,000 bytes, with MiB used to denote 1,048,576 bytes in precise binary contexts.

The term can be confused with megabit (Mb), which denotes 1,000,000 bits, not bytes, or with the now-common practice of using MB for both sizes depending on context. To avoid ambiguity, technical communication should specify exact byte counts or use MB for 1,000,000 bytes and MiB for 1,048,576 bytes.

Examples: a file sized 2 MB equals about 2,000,000 bytes; if interpreted as MiB, it would be about 2,097,152 bytes. In network speeds, megabits per second (Mbps) is standard; storage capacities typically use bytes.

See also: bytes, megabyte, mebibyte, megabit, binary prefixes.