Kilobytes to Bytes (kB to B)

1 kilobyte equals 1,000 bytes exactly.

1 kilobyte = 1,000 bytes

How to convert kilobytes to bytes

To convert kilobytes to bytes, multiply the number of kilobytes by 1,000. This factor is exact. To go the other way, multiply bytes by 0.001.

bytes = kilobytes × 1,000

Example: 10 kilobytes = 10,000 bytes.

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

Byte (B)

ComputingCurrent unit

Eight bits. The basic addressable unit of memory and storage.

Werner Buchholz coined the word byte in June 1956 while working on the IBM Stretch computer; the earliest supporting document is dated 11 June 1956. He respelled bite on purpose, in his words to avoid accidental mutation to bit. At that stage a byte was any group of one to six bits, and a move to eight bits was considered in August 1956 and built into the design soon after. Louis Dooley later claimed he had coined the term around 1956 or 1957 on the SAGE project at MIT Lincoln Laboratory, where it meant groups of four bits, but Fred Brooks credited Buchholz.

IBM's System/360 adopted the eight-bit byte, and its success made that size the standard. The symbol is a capital B, and the unambiguous alternative is octet, a word used in protocol standards such as RFC 791. A byte can hold 256 distinct values, enough for a letter of the alphabet in a simple character set, which is why files and memory addresses are counted in bytes.

The byte is the reference unit for digital storage on this site.

Sources: Wikipedia: Byte; Wikipedia: Binary prefix

Related conversions

See all digital storage units.