Data-rate units

Unit of measurement

Bit rates (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

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 multiples of bits per second (bit/s) and bytes 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

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See also: Bit rate

### Unit symbol

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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. 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 Institute of Electrical and Electronics Engineers (IEEE) uses the symbol b for bit.

### Unit prefixes

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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 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

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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

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

### Kilobit per second

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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

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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

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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

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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

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These units are often not used in the suggested ways; see § Variations.

### Kilobyte per second

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kilobyte per second (kB/s) (sometimes abbreviated "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

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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

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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

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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

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Name  | Symbol  | bit per second  | byte per second  | bit per second
(formula)  | byte per second
(formula)

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|
|
|
|

bit per second  | bit/s  | 1  | 0.125  | 1  | ⁠1/8⁠
byte per second  | B/s  | 8  | 1  | 8  | 1
kilobit per second  | kbit/s  | 1,000  | 125  | 103 | ⁠1/8⁠ × 103
kibibit per second  | Kibit/s  | 1,024  | 128  | 210 | 27
kilobyte per second  | kB/s  | 8,000  | 1,000  | 8 × 103 | 103
kibibyte per second  | KiB/s  | 8,192  | 1,024  | 213 | 210
megabit per second  | Mbit/s  | 1,000,000  | 125,000  | 106 | ⁠1/8⁠ × 106
mebibit per second  | Mibit/s  | 1,048,576  | 131,072  | 220 | 217
megabyte per second  | MB/s  | 8,000,000  | 1,000,000  | 8 × 106 | 106
mebibyte per second  | MiB/s  | 8,388,608  | 1,048,576  | 223 | 220
gigabit per second  | Gbit/s  | 1,000,000,000  | 125,000,000  | 109 | ⁠1/8⁠ × 109
gibibit per second  | Gibit/s  | 1,073,741,824  | 134,217,728  | 230 | 227
gigabyte per second  | GB/s  | 8,000,000,000  | 1,000,000,000  | 8 × 109 | 109
gibibyte per second  | GiB/s  | 8,589,934,592  | 1,073,741,824  | 233 | 230
terabit per second  | Tbit/s  | 1,000,000,000,000  | 125,000,000,000  | 1012 | ⁠1/8⁠ × 1012
tebibit per second  | Tibit/s  | 1,099,511,627,776  | 137,438,953,472  | 240 | 237
terabyte per second  | TB/s  | 8,000,000,000,000  | 1,000,000,000,000  | 8 × 1012 | 1012
tebibyte per second  | TiB/s  | 8,796,093,022,208  | 1,099,511,627,776  | 243 | 240

## Examples of bit rates

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Main article: List of interface bit rates

Quantity  | Unit  | bits per second  | bytes per second  | Field  | Description

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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 an ISDN B 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 VTC T1.
10  | Mbit/s  | 10,000,000  | 1,250,000  | Networking  | 107 bit/s is the speed of classic Ethernet: 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. 107 bit/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 4 submarine communications cable – 1.28 terabits per second[3]
4  | kbit/s  | 4,000  | 500  | Audio data  | minimum achieved for encoding recognizable speech (using special-purpose speech codecs)
8  | kbit/s  | 8,000  | 1,000  | Audio data  | low bit rate telephone quality
32  | kbit/s  | 32,000  | 4,000  | Audio data  | MW quality 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/s MP3 – 128,000 bit/s
192  | kbit/s  | 192,000  | 24,000  | Audio data  | 192 kbit/s MP3 – 192,000 bit/s
1,411.2  | kbit/s  | 1,411,200  | 176,400  | Audio data  | CD audio (uncompressed, 16 bit samples × 44.1 kHz × 2 channels)
2  | Mbit/s  | 2,000,000  | 250,000  | Video data  | 30 channels of telephone audio or a Video Tele-Conference at VHS quality
8  | Mbit/s  | 8,000,000  | 1,000,000  | Video data  | DVD quality
27  | Mbit/s  | 27,000,000  | 3,375,000  | Video data  | HDTV quality
1.244  | Gbit/s  | 1,244,000,000  | 155,500,000  | Networking  | OC-24, a 1.244 Gbit/s SONET data channel
9.953  | Gbit/s  | 9,953,000,000  | 1,244,125,000  | Networking  | OC-192, a 9.953 Gbit/s SONET data channel
39.813  | Gbit/s  | 39,813,000,000  | 4,976,625,000  | Networking  | OC-768, a 39.813 Gbit/s SONET data channel, the fastest in current use
60  | MB/s  | 480,000,000  | 60,000,000  | Computer data interfaces  | USB 2.0 High-Speed
98.3  | MB/s  | 786,432,000  | 98,304,000  | Computer data interfaces  | FireWire IEEE 1394b-2002 S800
120  | MB/s  | 960,000,000  | 120,000,000  | Computer data interfaces  | Harddrive read, Samsung SpinPoint F1 HD103Uj[4]
133  | MB/s  | 1,064,000,000  | 133,000,000  | Computer data interfaces  | Parallel ATA UDMA 6
133  | MB/s  | 1,064,000,000  | 133,000,000  | Computer data interfaces  | PCI 32-bit at 33 MHz (standard configuration)
188  | MB/s  | 1,504,000,000  | 188,000,000  | Computer data interfaces  | SATA I 1.5 Gbit/s – First generation
375  | MB/s  | 3,000,000,000  | 375,000,000  | Computer data interfaces  | SATA II 3 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 3.0 SuperSpeed - a.k.a. USB 3.1 Gen1
750  | MB/s  | 6,000,000,000  | 750,000,000  | Computer data interfaces  | SATA III 6 Gbit/s – Third generation
1,067  | MB/s  | 8,533,333,333  | 1,066,666,667  | Computer data interfaces  | PCI-X 64 bit 133 MHz
10  | Gbit/s  | 10,000,000,000  | 1,250,000,000  | Computer data interfaces  | USB 3.1 SuperSpeed+ - 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

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* Binary prefix
* Bit rate
* List of interface bit rates
* Orders of magnitude (bit rate)
* Orders of magnitude (data)
* Metric prefix
* Instructions per second

## Notes

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1. ^ "Penn Researchers Calculate How Much the Eye Tells the Brain". 26 July 2006.
2. ^ 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\. Bibcode:2006CBio...16.1428K. doi:10.1016/j.cub.2006.05.056. ISSN 0960-9822. PMC 1564115. PMID 16860742.
3. ^ "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.
4. ^ "Samsung overtakes". 21 November 2007.

## References

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* International Electrotechnical Commission (2007). "Prefixes for binary multiples" (archived). Retrieved on 2007-05-06. - updated page Archived 2020-05-11 at the Wayback Machine 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: "What is a kilobyte?" Archived 2016-03-05 at the Wayback Machine

## External links

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* Valid8 Data Rate Calculator