Kilobytes to Kibibits (kB to Kibit)

1 kilobyte equals 7.8125 kibibits exactly.

How to convert kilobytes to kibibits

To convert kilobytes to kibibits, multiply the number of kilobytes by 7.8125. This factor is exact. To go the other way, multiply kibibits by 0.128.

kibibits = kilobytes × 7.8125

Example: 10 kilobytes = 78.125 kibibits.

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

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

Kibibit (Kibit)

ComputingCurrent unit

Exactly 1,024 bits.

Before 1999, a kilobit was often loosely taken to mean 1,024 bits as well as 1,000, and the IEC prefix kibi settled the matter. A kibibit (Kibit) is exactly 2^10 bits, which is 1,024 bits or 128 bytes. The IEC adopted the prefix in December 1998, and the BIPM's vocabulary of metrology notes that 1 kilobit should not be used to mean 1,024 bits.

The name starts with the first two letters of kilo and adds bi for binary, and the symbol writes the K as a capital to match the other binary prefixes. The difference from the decimal kilobit is 2.4 percent, the smallest of any pair.

The unit is a small one, equal to 128 bytes, and appears mainly where an exact binary bit count has to be stated without the ambiguity of kilobit.

1 kibibit = 128 bytes (exactly).

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

Related conversions

See all digital storage units.