Kilobit

The kilobit is a multiple of the unit bit for digital information or computer storage. The prefix kilo- (symbol k) is defined in the International System of Units (SI) as a multiplier of 10³ (1 thousand),[1] and therefore,

1 kilobit = 10³bits = 1000 bits.

This article is about the unit of 1000 bits. For the unit of 1024 bits, see kibibit.

Not to be confused with kilobyte.

Multiples of bits
Decimal Value SI 1000 10^3 kbit kilobit 1000^2 10^6 Mbit megabit 1000^3 10^9 Gbit gigabit 1000^4 10^12 Tbit terabit 1000^5 10^15 Pbit petabit 1000^6 10^18 Ebit exabit 1000^7 10^21 Zbit zettabit 1000^8 10^24 Ybit yottabit	Binary Value IEC JEDEC 1024 2^10 Kibit kibibit Kbit kilobit 1024^2 2^20 Mibit mebibit Mbit megabit 1024^3 2^30 Gibit gibibit Gbit gigabit 1024^4 2^40 Tibit tebibit - 1024^5 2^50 Pibit pebibit - 1024^6 2^60 Eibit exbibit - 1024^7 2^70 Zibit zebibit - 1024^8 2^80 Yibit yobibit -
See also Nibble Byte Orders of magnitude of data

The kilobit has the unit symbol kbit or kb.

Using the common byte size of 8 bits, 1 kbit is equal to 125 bytes.

The kilobit is commonly used in the expression of data rates of digital communication circuits as kilobits per second (kbit/s or kb/s), or abbreviated as kbps,[2] as in, for example, a 56 kbps PSTN circuit, or a 512 kbit/s broadband Internet connection.

The unit symbol kb (lowercase 'b') is typographically similar to the international standard unit symbol for the kilobyte, i.e. kB (upper case 'B'). The International Electrotechnical Commission (IEC) recommends the symbol bit instead of b. The prefix kilo- is often used in fields of computer science and information technology with a meaning of multiplication by 1024 instead of 1000, contrary to international standards, in conjunction with the base unit byte and bit, in which case it is to be written as Ki-, with a capital letter K,[3] e.g., 1 Kibit = 1024 bits. The decimal SI definition, 1 kbit/s = 1000 bit/s, is used uniformly in the context of telecommunication transmission speeds.

The kilobit is closely related to the much less used kibibit, a unit multiple derived from the binary prefix kibi- (symbol Ki) of the same order of magnitude,[3] which is equal to 2¹⁰bits = 1024 bits, or approximately 2% larger than the kilobit. Despite the definitions of these new prefixes, meant for binary-based quantities of storage by international standards organizations, memory semiconductor chips are still marketed using the metric prefix names to designate binary multiples.

See also

• Data rate units
• Orders of magnitude (data)
• SI prefix

References

1. "Definitions of the SI units: The twenty SI prefixes". physics.nist.gov.
2. "Services Update". webservices.ieee.org.
3. "Definitions of the SI units: The binary prefixes". physics.nist.gov.