Data rate units

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Bit rates
NameSymbolMultiple
Decimal prefixes (SI)
kilobit per secondkbit/s103
megabit per secondMbit/s106
gigabit per secondGbit/s109
terabit per secondTbit/s1012
Binary prefixes (IEC 80000-13)
kibibit per secondKibit/s210
mebibit per secondMibit/s220
gibibit per secondGibit/s230
tebibit per secondTibit/s240
 
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Bit rates
NameSymbolMultiple
Decimal prefixes (SI)
kilobit per secondkbit/s103
megabit per secondMbit/s106
gigabit per secondGbit/s109
terabit per secondTbit/s1012
Binary prefixes (IEC 80000-13)
kibibit per secondKibit/s210
mebibit per secondMibit/s220
gibibit per secondGibit/s230
tebibit per secondTibit/s240

In telecommunications, data transfer rate is the average number of bits (bitrate), characters or symbols (baudrate), or blocks (packet rate) per unit time passing between equipment in a data transmission system. Most commonly, measurements of data transfer rate are reported in multiples of unit bits per second (bit/s) or occasionally in bytes per second (B/s). The data rates of modern residential high-speed Internet connections are most commonly expressed in multiples of bits per second, such as megabits per second (Mbit/s).

Standards for unit symbols and prefixes[edit]

See also: Bit rate for the differences between gross bitrate and net bitrate and between throughput and goodput.

Unit symbol[edit]

The ISQ symbols for the bit and byte are bit and B. In the context of data rate units, one byte consists of 8 bits, and is synonymous with the unit octet. 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). The IEEE uses the symbol b for bit.

Prefix[edit]

In both the SI and ISQ, the prefix k stands for kilo, meaning 1000, while Ki is the symbol for the binary prefix kibi-, meaning 1024. The binary prefixes were introduced in 1998 by the International Electrotechnical Commission (IEC) and in IEEE 1541-2002 which was reaffirmed on 27 March 2008. The letter K is often used as a non-standard abbreviation for 1024, especially in "KB" to mean KiB, the kilobyte in its binary sense.

Variations[edit]

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 be used only to mean powers of 10 and never powers of 2.

Decimal multiples of bits[edit]

These units are often used in a manner inconsistent with the IEC standard. See above section titled "variations".

Kilobit per second[edit]

kilobit per second (symbol kbit/s or kb/s, often abbreviated "kbps") is a unit of data transfer rate equal to:

Megabit per second[edit]

megabit per second (symbol Mbit/s or Mb/s, often abbreviated "Mbps") is a unit of data transfer rate equal to:

Gigabit per second[edit]

gigabit per second (symbol Gbit/s or Gb/s, often abbreviated "Gbps") is a unit of data transfer rate equal to:

Terabit per second[edit]

terabit per second (symbol Tbit/s or Tb/s, sometimes abbreviated "Tbps") is a unit of data transfer rate equal to:

Binary multiples of bits[edit]

For more details on prefixes such as kibi, mebi, gibi, tebi, see Binary prefix.

The prefix name for binary prefixes (e.g., "kibi") is not capitalized, but the prefix symbol (e.g. "Ki") is.

Kibibit per second[edit]

The kibibit per second (Kibit/s) is a unit of data transfer rate equal to:

Mebibit per second[edit]

The mebibit per second (Mibit/s) is a unit of data transfer rate equal to:

Gibibit per second[edit]

The gibibit per second (Gibit/s) is a unit of data transfer rate equal to:

Tebibit per second[edit]

The tebibit per second (Tibit/s) is a unit of data transfer rate equal to:

Decimal multiples of bytes[edit]

These units are often not used in the suggested ways! See above section titled "variations".

Kilobyte per second[edit]

kilobyte per second (kB/s) is a unit of data transfer rate equal to:

Megabyte per second[edit]

megabyte per second (MB/s) is a unit of data transfer rate equal to:

Gigabyte per second[edit]

gigabyte per second (GB/s) is a unit of data transfer rate equal to:

Terabyte per second[edit]

terabyte per second (TB/s) is a unit of data transfer rate equal to:

Binary multiples of bytes[edit]

For more details on prefixes such as kibi-, mebi-, gibi-, and tebi-, see Binary prefix.

Kibibyte per second[edit]

The kibibyte per second (KiB/s) is a unit of data transfer rate equal to:

Mebibyte per second[edit]

The mebibyte per second (MiB/s) is a unit of data transfer rate equal to:

Gibibyte per second[edit]

The gibibyte per second (GiB/s) is a unit of data transfer rate equal to:

Tebibyte per second[edit]

The tebibyte per second (TiB/s) is a unit of data transfer rate equal to:

Conversion table[edit]

NameSymbolbit per secondbyte per secondbit per second (formula)byte per second (formula)
bit per secondbit/s10.12511/8
byte per secondB/s8181
kilobit per secondkbit/s1,000125103103/8
kibibit per secondKibit/s1,02412821027
kilobyte per secondkB/s8,0001,0008x103103
kibibyte per secondKiB/s8,1921,024213210
megabit per secondMbit/s1,000,000125,000106106/8
mebibit per secondMibit/s1,048,576131,072220217
megabyte per secondMB/s8,000,0001,000,0008x106106
mebibyte per secondMiB/s8,388,6081,048,576223220
gigabit per secondGbit/s1,000,000,000125,000,000109109/8
gibibit per secondGibit/s1,073,741,957134,217,728230227
gigabyte per secondGB/s8,000,000,0001,000,000,0008x109109
gibibyte per secondGiB/s8,589,934,5921,073,741,824233230
terabit per secondTbit/s1,000,000,000,000125,000,000,00010121012/8
tebibit per secondTibit/s1,099,511,627,776137,438,953,472240237
terabyte per secondTB/s8,000,000,000,0001,000,000,000,0008x10121012
tebibyte per secondTiB/s8,796,093,022,2081,099,511,627,776243240

Examples of bit rates[edit]

QuantityUnitbits per secondbytes per secondFieldDescription
56kbit/s56,0007,000Networking56kbit modem – 56 kbit/s – 56,000 bit/s
64kbit/s64,0008,000Networking64kbit/s in an ISDN B channel or best quality, uncompressed telephone line.
1,536kbit/s1,536,000192,000Networking24 channels of telephone in the US, or a good VTC T1.
10Mbit/s10,000,0001,250,000Networking107 bit/s is the speed of classic Ethernet: 10BASE2, 10BASE5, 10BASE-T
10Mbit/s10,000,0001,250,000BiologyResearch suggests that the human retina transmits data to the brain at the rate of ca. 107 bit/sec[1]
1Gbit/s1,000,000,000125,000,000NetworkingGigabit Ethernet
10Gbit/s10,000,000,0001,250,000,000Networking10 Gigabit Ethernet
1Tbit/s1,000,000,000,000125,000,000,000NetworkingSEA-ME-WE 4 submarine communications cable – 1.28 terabits per second[2]
4kbit/s4,000500Audio dataminimum achieved for encoding recognizable speech (using special-purpose speech codecs)
8kbit/s8,0001,000Audio datalow bit rate telephone quality
32kbit/s32,0004,000Audio dataMW quality and ADPCM voice in telephony, doubling the capacity of a 30 chan link to 60 ch.
128kbit/s128,00016,000Audio data128 kbit/s MP3 – 128,000 bit/s
192kbit/s192,00024,000Audio data192 kbit/s MP3 – 192,000 bit/s
1,411.2kbit/s1,411,200176,400Audio dataCD audio (uncompressed, 16 bit samples × 44.1 kHz × 2 channels)
2Mbit/s2,000,000250,000Video data30 channels of telephone audio or a Video Tele-Conference at VHS quality
8Mbit/s8,000,0001,000,000Video dataDVD quality
27Mbit/s27,000,0003,375,000Video dataHDTV quality
1.244Gbit/s1,244,000,000155,500,000NetworkingOC-24, a 1.244 Gbit/s SONET data channel
9.953Gbit/s9,953,000,0001,244,125,000NetworkingOC-192, a 9.953 Gbit/s SONET data channel
39.813Gbit/s39,813,000,0004,976,625,000NetworkingOC-768, a 39.813 Gbit/s SONET data channel, the fastest in current use
60MB/s480,000,00060,000,000Computer data interfacesUSB 2.0 High-Speed
625MB/s5,000,000,000625,000,000Computer data interfacesUSB 3.0 SuperSpeed
98.3MB/s786,432,00098,304,000Computer data interfacesFireWire IEEE 1394b-2002 S800
120MB/s960,000,000120,000,000Computer data interfacesHarddrive read, Samsung SpinPoint F1 HD103Uj[3]
133MB/s1,064,000,000133,000,000Computer data interfacesParallel ATA UDMA 6
133MB/s1,064,000,000133,000,000Computer data interfacesPCI 32-bit at 33 MHz (standard configuration)
188MB/s1,504,000,000188,000,000Computer data interfacesSATA I 1.5 Gbit/s – First generation
375MB/s3,000,000,000375,000,000Computer data interfacesSATA II 3Gbit/s – Second generation
500MB/s4,000,000,000500,000,000Computer data interfacesPCI Express x1 v2.0
750MB/s6,000,000,000750,000,000Computer data interfacesSATA III 6 Gbit/s – Third generation
1067MB/s5,533,333,3331,066,666,667Computer data interfacesPCI-X 64 bit 133 MHz
1250MB/s10,000,000,0001,250,000,000Computer data interfacesThunderbolt
2500MB/s20,000,000,0002,500,000,000Computer data interfacesThunderbolt 2
8000MB/s64,000,000,0008,000,000,000Computer data interfacesPCI Express x16 v2.0
12000MB/s96,000,000,00012,000,000,000Computer data interfacesInfiniBand 12X QDR
16000MB/s128,000,000,00016,000,000,000Computer data interfacesPCI Express x16 v3.0

See also[edit]

Notes[edit]

  1. ^ Penn researchers calculate how much the eye tells the brain, 26 July 2006
  2. ^ "Fujitsu Completes Construction of SEA-ME-WE 4 Submarine Cable Network". Fujitsu Press Releases. Fujitsu. 2005-12-13. Archived from the original on 2007-03-17. Retrieved 2008-01-31. 
  3. ^ "Samsung overtakes". 

References[edit]