Mebibyte (MiB)

Definition

One binary megabyte, 1024² bytes (2²⁰ B) — the "MB" an operating system often shows.

History

The mebibyte was defined by the IEC in 1998 as the binary counterpart to the megabyte, exactly 1024² bytes. It removed the old ambiguity between a million bytes and 1,048,576 bytes.

Where it is used

The mebibyte is what an operating system often labels MB, so a file the OS calls 1 MB is really 1 MiB, about 1.049 decimal MB.

Typical uses include reported file sizes, memory.

Conversion pages

These pages convert mebibyte to or from another unit in digital storage.

No conversion pages use this unit yet.

Other Digital storage units

• Byte (B)
• Bit (bit)
• Kilobyte (kB)
• Megabyte (MB)
• Gigabyte (GB)
• Terabyte (TB)
• Gibibyte (GiB)
• Tebibyte (TiB)

Sources

• IEC 80000-13 IEC 80000-13 (quantities and units — information science); NIST on binary prefixes · Dataset reviewed Nov 11, 2026