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telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that ...
, data-transfer rate is the average number of bits ( bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multiples of
bits per second In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...
(bit/s) and
bytes per second In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...
(B/s). For example, the data rates of modern residential high-speed Internet connections are commonly expressed in megabits per second (Mbit/s).


Standards for unit symbols and prefixes


Unit symbol

The ISQ symbols for the bit and byte are ''bit'' and ''B'', respectively. In the context of data-rate units, one byte consists of 8 bits, and is synonymous with the unit
octet Octet may refer to: Music * Octet (music), ensemble consisting of eight instruments or voices, or composition written for such an ensemble ** String octet, a piece of music written for eight string instruments *** Octet (Mendelssohn), 1825 com ...
. The abbreviation bps is often used to mean bit/s, so that when a ''1 Mbps'' connection is advertised, it usually means that the maximum achievable bandwidth is 1 Mbit/s (one million bits per second), which is 0.125 MB/s ( megabyte per second), or about 0.1192 MiB/s (
mebibyte per second In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mul ...
). The
Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...
(IEEE) uses the symbol b for bit.


Unit prefixes

In both the SI and ISQ, the prefix k stands for kilo, meaning 1,000, while Ki is the symbol for the
binary prefix A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power  ...
kibi-, meaning 1,024. The binary prefixes were introduced in 1998 by the
International Electrotechnical Commission The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and ...
(IEC) and in
IEEE 1541-2002 IEEE 1541-2002 is a standard issued in 2002 by the Institute of Electrical and Electronics Engineers (IEEE) concerning the use of prefixes for binary multiples of units of measurement related to digital electronics and computing. While the In ...
which was reaffirmed on 27 March 2008. The letter K is often used as a non-standard abbreviation for 1,024, especially in "KB" to mean KiB, the kilobyte in its binary sense. In the context of data rates, however, typically only decimal prefixes are used, and they have their standard SI interpretation.


Variations

In 1999, the IEC published Amendment 2 to " IEC 60027-2: Letter symbols to be used in electrical technology – Part 2: Telecommunications and electronics". This standard, approved in 1998, introduced the prefixes kibi-, mebi-, gibi-, tebi-, pebi-, and exbi- to be used in specifying binary multiples of a quantity. The name is derived from the first two letters of the original SI prefixes followed by bi (short for ''binary''). It also clarifies that the SI prefixes are used only to mean powers of 10 and never powers of 2.


Decimal multiples of bits

These units are often used in a manner inconsistent with the IEC standard.


Kilobit per second

Kilobit per second (symbol kbit/s or kb/s, often abbreviated "kbps") is a unit of data transfer rate equal to: * 1,000 bits per second * 125 bytes per second


Megabit per second

Megabit per second (symbol Mbit/s or Mb/s, often abbreviated "Mbps") is a unit of data transfer rate equal to: * 1,000 kilobits per second * 1,000,000 bits per second * 125,000 bytes per second * 125 kilobytes per second


Gigabit per second

Gigabit per second (symbol Gbit/s or Gb/s, often abbreviated "Gbps") is a unit of data transfer rate equal to: * 1,000 megabits per second * 1,000,000 kilobits per second * 1,000,000,000 bits per second * 125,000,000 bytes per second * 125 megabytes per second


Terabit per second

Terabit per second (symbol Tbit/s or Tb/s, sometimes abbreviated "Tbps") is a unit of data transfer rate equal to: * 1,000 gigabits per second * 1,000,000 megabits per second * 1,000,000,000 kilobits per second * 1,000,000,000,000 bits per second * 125,000,000,000 bytes per second * 125 gigabytes per second


Decimal multiples of bytes

These units are often not used in the suggested ways; see above section titled "
variations Variation or Variations may refer to: Science and mathematics * Variation (astronomy), any perturbation of the mean motion or orbit of a planet or satellite, particularly of the moon * Genetic variation, the difference in DNA among individua ...
".


Kilobyte per second

kilobyte per second (kB/s) (can be abbreviated as kBps) is a unit of data transfer rate equal to: * 8,000 bits per second * 1,000 bytes per second * 8 kilobits per second


Megabyte per second

megabyte per second (MB/s) (can be abbreviated as MBps) is a unit of data transfer rate equal to: * 8,000,000 bits per second * 1,000,000 bytes per second * 1,000 kilobytes per second * 8 megabits per second


Gigabyte per second

gigabyte per second (GB/s) (can be abbreviated as GBps) is a unit of data transfer rate equal to: * 8,000,000,000 bits per second * 1,000,000,000 bytes per second * 1,000,000 kilobytes per second * 1,000 megabytes per second * 8 gigabits per second


Terabyte per second

terabyte per second (TB/s) (can be abbreviated as TBps) is a unit of data transfer rate equal to: * 8,000,000,000,000 bits per second * 1,000,000,000,000 bytes per second * 1,000,000,000 kilobytes per second * 1,000,000 megabytes per second * 1,000 gigabytes per second * 8 terabits per second


Conversion table


Examples of bit rates


See also

*
Binary prefix A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power  ...
*
Bit rate In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...
*
List of interface bit rates This is a list of interface bit rates, is a measure of information transfer rates, or digital bandwidth capacity, at which digital interfaces in a computer or network can communicate over various kinds of buses and channels. The distinction can ...
* Orders of magnitude (bit rate) * Orders of magnitude (data) *
Metric prefix A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The pr ...
*
Instructions per second Instructions per second (IPS) is a measure of a computer's processor speed. For complex instruction set computers (CISCs), different instructions take different amounts of time, so the value measured depends on the instruction mix; even for co ...


Notes


References

* International Electrotechnical Commission (2007).
Prefixes for binary multiples
(archived). Retrieved on 2007-05-06.

lacks table but now references IEC 80000-13:2008 rather than IEC 60027-2.
IEC 60027-2 "Letter symbols to be used in electrical technology – Part 2: Telecommunications and electronics+
*
Donald Knuth Donald Ervin Knuth ( ; born January 10, 1938) is an American computer scientist, mathematician, and professor emeritus at Stanford University. He is the 1974 recipient of the ACM Turing Award, informally considered the Nobel Prize of computer sc ...

"What is a kilobyte?"


External links


Valid8 Data Rate Calculator
{{DEFAULTSORT:Data Rate Units Data transmission Units of flow Units of information Units of temporal rate