Data-rate units
Name | Symbol | Multiple | |
---|---|---|---|
bit per second | bit/s | 1 | 1 |
Metric prefixes(SI) | |||
kilobit per second | kbit/s | 103 | 10001 |
megabit per second | Mbit/s | 106 | 10002 |
gigabit per second | Gbit/s | 109 | 10003 |
terabit per second | Tbit/s | 1012 | 10004 |
Binary prefixes(IEC 80000-13) | |||
kibibit per second | Kibit/s | 210 | 10241 |
mebibit per second | Mibit/s | 220 | 10242 |
gibibit per second | Gibit/s | 230 | 10243 |
tebibit per second | Tibit/s | 240 | 10244 |
Intelecommunications,data transfer rateis the average number ofbits(bitrate), characters or symbols (baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Commondata rate unitsare multiples ofbits per second(bit/s) andbytes per second(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
[edit]Unit symbol
[edit]TheISQsymbols for the bit and byte arebitandB,respectively. In the context of data-rate units, one byte consists of 8 bits, and is synonymous with the unitoctet.The abbreviation bps is often used to mean bit/s, so that when a1 Mbpsconnection 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). TheInstitute of Electrical and Electronics Engineers(IEEE) uses the symbol b for bit.
Unit prefixes
[edit]In both theSIand ISQ, the prefix k stands forkilo,meaning 1000, while Ki is the symbol for thebinary prefixkibi-,meaning 1024. The binary prefixes were introduced in 1998 by theInternational Electrotechnical Commission(IEC) and inIEEE 1541-2002which 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, thekilobyte 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
[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 forbinary). It also clarifies that the SI prefixes are 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.
Kilobit per second
[edit]Kilobit per second(symbolkbit/sorkb/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
[edit]Megabit per second(symbolMbit/sorMb/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
[edit]Gigabit per second(symbolGbit/sorGb/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
[edit]Terabit per second(symbolTbit/sorTb/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
[edit]These units are often not used in the suggested ways; see§ Variations.
Kilobyte per second
[edit]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
[edit]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
[edit]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
[edit]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
[edit]Name | Symbol | bit per second | byte per second | bit per second (formula) |
byte per second (formula) |
---|---|---|---|---|---|
bitper second | bit/s | 1 | 0.125 | 1 | 1/8 |
byteper second | B/s | 8 | 1 | 8 | 1 |
kilobitper second | kbit/s | 1,000 | 125 | 103 | 1/8× 103 |
kibibitper second | Kibit/s | 1,024 | 128 | 210 | 27 |
kilobyteper second | kB/s | 8,000 | 1,000 | 8 × 103 | 103 |
kibibyteper second | KiB/s | 8,192 | 1,024 | 213 | 210 |
megabitper second | Mbit/s | 1,000,000 | 125,000 | 106 | 1/8× 106 |
mebibitper second | Mibit/s | 1,048,576 | 131,072 | 220 | 217 |
megabyteper second | MB/s | 8,000,000 | 1,000,000 | 8 × 106 | 106 |
mebibyteper second | MiB/s | 8,388,608 | 1,048,576 | 223 | 220 |
gigabitper second | Gbit/s | 1,000,000,000 | 125,000,000 | 109 | 1/8× 109 |
gibibitper second | Gibit/s | 1,073,741,824 | 134,217,728 | 230 | 227 |
gigabyteper second | GB/s | 8,000,000,000 | 1,000,000,000 | 8 × 109 | 109 |
gibibyteper second | GiB/s | 8,589,934,592 | 1,073,741,824 | 233 | 230 |
terabitper second | Tbit/s | 1,000,000,000,000 | 125,000,000,000 | 1012 | 1/8× 1012 |
tebibitper second | Tibit/s | 1,099,511,627,776 | 137,438,953,472 | 240 | 237 |
terabyteper second | TB/s | 8,000,000,000,000 | 1,000,000,000,000 | 8 × 1012 | 1012 |
tebibyteper second | TiB/s | 8,796,093,022,208 | 1,099,511,627,776 | 243 | 240 |
Examples of bit rates
[edit]Quantity | Unit | bits per second | bytes per second | Field | Description |
---|---|---|---|---|---|
56 | kbit/s | 56,000 | 7,000 | Networking | 56 kbit modem– 56,000 bit/s |
64 | kbit/s | 64,000 | 8,000 | Networking | 64 kbit/s in anISDNB channel or best quality, uncompressed telephone line. |
1,536 | kbit/s | 1,536,000 | 192,000 | Networking | 24 channels of telephone in the US, or a good VTCT1. |
10 | Mbit/s | 10,000,000 | 1,250,000 | Networking | 107bit/s is the speed of classicEthernet:10BASE2, 10BASE5, 10BASE-T |
10 | Mbit/s | 10,000,000 | 1,250,000 | Biology | Research suggests that the human retina transmits data to the brain at the rate of ca. 107bit/s[1][2][dubious–discuss] |
54 | Mbit/s | 54,000,000 | 6,750,000 | Networking | 802.11g,Wireless G LAN |
100 | Mbit/s | 100,000,000 | 12,500,000 | Networking | Fast Ethernet |
600 | Mbit/s | 600,000,000 | 75,000,000 | Networking | 802.11n,Wireless N LAN |
1 | Gbit/s | 1,000,000,000 | 125,000,000 | Networking | 1 Gigabit Ethernet |
10 | Gbit/s | 10,000,000,000 | 1,250,000,000 | Networking | 10 Gigabit Ethernet |
100 | Gbit/s | 100,000,000,000 | 12,500,000,000 | Networking | 100 Gigabit Ethernet |
1 | Tbit/s | 1,000,000,000,000 | 125,000,000,000 | Networking | SEA-ME-WE 4submarine communications cable– 1.28 terabits per second[3] |
4 | kbit/s | 4,000 | 500 | Audio data | minimum achieved for encoding recognizable speech (using special-purposespeech codecs) |
8 | kbit/s | 8,000 | 1,000 | Audio data | low bit ratetelephonequality |
32 | kbit/s | 32,000 | 4,000 | Audio data | MWquality and ADPCM voice in telephony, doubling the capacity of a 30 chan link to 60 ch. |
128 | kbit/s | 128,000 | 16,000 | Audio data | 128 kbit/sMP3– 128,000 bit/s |
192 | kbit/s | 192,000 | 24,000 | Audio data | 192 kbit/sMP3– 192,000 bit/s |
1,411.2 | kbit/s | 1,411,200 | 176,400 | Audio data | CD audio(uncompressed, 16 bit samples × 44.1kHz× 2 channels) |
2 | Mbit/s | 2,000,000 | 250,000 | Video data | 30 channels of telephone audio or a Video Tele-Conference atVHSquality |
8 | Mbit/s | 8,000,000 | 1,000,000 | Video data | DVDquality |
27 | Mbit/s | 27,000,000 | 3,375,000 | Video data | HDTVquality |
1.244 | Gbit/s | 1,244,000,000 | 155,500,000 | Networking | OC-24,a 1.244 Gbit/sSONETdata channel |
9.953 | Gbit/s | 9,953,000,000 | 1,244,125,000 | Networking | OC-192,a 9.953 Gbit/sSONETdata channel |
39.813 | Gbit/s | 39,813,000,000 | 4,976,625,000 | Networking | OC-768,a 39.813 Gbit/sSONETdata channel, the fastest in current use |
60 | MB/s | 480,000,000 | 60,000,000 | Computer data interfaces | USB 2.0High-Speed |
98.3 | MB/s | 786,432,000 | 98,304,000 | Computer data interfaces | FireWireIEEE 1394b-2002 S800 |
120 | MB/s | 960,000,000 | 120,000,000 | Computer data interfaces | Harddriveread, Samsung SpinPoint F1 HD103Uj[4] |
133 | MB/s | 1,064,000,000 | 133,000,000 | Computer data interfaces | Parallel ATAUDMA 6 |
133 | MB/s | 1,064,000,000 | 133,000,000 | Computer data interfaces | PCI 32-bitat 33 MHz (standard configuration) |
188 | MB/s | 1,504,000,000 | 188,000,000 | Computer data interfaces | SATA I1.5 Gbit/s – First generation |
375 | MB/s | 3,000,000,000 | 375,000,000 | Computer data interfaces | SATA II3 Gbit/s – Second generation |
500 | MB/s | 4,000,000,000 | 500,000,000 | Computer data interfaces | PCI Express x1 v2.0 |
5.0 | Gbit/s | 5,000,000,000 | 625,000,000 | Computer data interfaces | USB 3.0SuperSpeed - a.k.a.USB 3.1Gen1 |
750 | MB/s | 6,000,000,000 | 750,000,000 | Computer data interfaces | SATA III6 Gbit/s – Third generation |
1,067 | MB/s | 8,533,333,333 | 1,066,666,667 | Computer data interfaces | PCI-X64 bit 133 MHz |
10 | Gbit/s | 10,000,000,000 | 1,250,000,000 | Computer data interfaces | USB 3.1SuperSpeed+ - a.k.a. USB 3.1 Gen2 |
1,250 | MB/s | 10,000,000,000 | 1,250,000,000 | Computer data interfaces | Thunderbolt |
2,500 | MB/s | 20,000,000,000 | 2,500,000,000 | Computer data interfaces | Thunderbolt 2 |
5,000 | MB/s | 40,000,000,000 | 5,000,000,000 | Computer data interfaces | Thunderbolt 3 |
8,000 | MB/s | 64,000,000,000 | 8,000,000,000 | Computer data interfaces | PCI Express x16 v2.0 |
12,000 | MB/s | 96,000,000,000 | 12,000,000,000 | Computer data interfaces | InfiniBand 12X QDR |
16,000 | MB/s | 128,000,000,000 | 16,000,000,000 | Computer data interfaces | PCI Express x16 v3.0 |
See also
[edit]- Binary prefix
- Bit rate
- List of interface bit rates
- Orders of magnitude (bit rate)
- Orders of magnitude (data)
- Metric prefix
- Instructions per second
Notes
[edit]- ^"Penn Researchers Calculate How Much the Eye Tells the Brain".26 July 2006.
- ^Koch, Kristin; McLean, Judith; Segev, Ronen; Freed, Michael A.; Berry, Michael J.; Balasubramanian, Vijay; Sterling, Peter (2006-07-25)."How Much the Eye Tells the Brain".Current Biology.16(14): 1428–1434.doi:10.1016/j.cub.2006.05.056.ISSN0960-9822.PMC1564115.PMID16860742.
- ^"Fujitsu Completes Construction of SEA-ME-WE 4 Submarine Cable Network".Fujitsu Press Releases.Fujitsu. 2005-12-13. Archived fromthe originalon 2007-03-17.Retrieved2008-01-31.
- ^"Samsung overtakes".21 November 2007.
References
[edit]- International Electrotechnical Commission (2007). "Prefixes for binary multiples"(archived). Retrieved on 2007-05-06. -updated pageArchived2020-05-11 at theWayback Machinelacks 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:"What is a kilobyte?"Archived2016-03-05 at theWayback Machine