Megabits to Kilobytes (Mb to kB)

1 megabit equals 125 kilobytes exactly.

How to convert megabits to kilobytes

To convert megabits to kilobytes, multiply the number of megabits by 125. This factor is exact. To go the other way, multiply kilobytes by 0.008.

kilobytes = megabits × 125

Example: 10 megabits = 1,250 kilobytes.

Decimal prefixes (kB, MB, GB) are powers of 1,000; binary prefixes (KiB, MiB, GiB) are powers of 1,024. Storage makers use decimal; Windows reports binary but labels it GB.

About these units

Megabit (Mb)

ComputingCurrent unit

1,000,000 bits (125,000 bytes). Internet speeds are advertised in megabits per second.

Megabit is the unit behind most internet plans: speeds are quoted in megabits per second, while files are sized in megabytes. Since a byte is eight bits, a megabit is one eighth of a megabyte, which is 125,000 bytes in decimal units, and an advertised speed in Mbit/s therefore looks eight times larger than the same rate in megabytes per second. Data transfer rates are usually measured in decimal SI multiples.

Writing it is tricky. The IEC symbol is Mbit and the IEEE recommends Mb, but a capital M with lowercase b is easy to confuse with MB, the megabyte. The binary counterpart, the mebibit, is rarely used. Memory chips are sometimes sized in megabits too, so check which unit a spec sheet is using before comparing numbers.

1 megabit = 125,000 bytes (exactly).

Sources: Wikipedia: Bit; Wikipedia: Megabit

Kilobyte (kB)

ComputingCurrent unit

1,000 bytes in the SI (decimal) definition. Older software and Windows sometimes use KB to mean 1,024 bytes; see kibibyte.

Few units have had two meanings for so long. By the mid-1960s most computers used binary addressing, so memory sizes came in powers of two and engineers borrowed kilo to mean 1,024. IBM documentation for the System/360 in 1964 used an uppercase K for 1,024. Hard disk makers took a different path from the start. The IEC later settled the question: kilobyte, symbol kB, means 1,000 bytes, and 1,024 bytes is a kibibyte.

Floppy disks show the muddle. The Shugart SA-400 of 1976 held 109,375 bytes unformatted and was advertised as 110 Kbyte, the decimal way, while a 1978 Tandon double-density disk held 368,640 bytes, or 360 times 1,024, and was sold as 360 KB. Windows still divides by 1,024, so a 65,536-byte file appears as 64 KB there, while Mac OS X Snow Leopard and later would call it 66 kB. A kilobyte is also tiny: Edgar Allan Poe's The Cask of Amontillado is 12,843 bytes.

1 kilobyte = 1,000 bytes (exactly).

Sources: Wikipedia: Kilobyte; Wikipedia: Binary prefix; NIST: Prefixes for binary multiples

Related conversions

See all digital storage units.