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).
See also: Bit rate.
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.
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.
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.
These units are often used in a manner inconsistent with the IEC standard.
Kilobit per second (symbol kbit/s or kb/s, often abbreviated "kbps") is a unit of data transfer rate equal to:
Megabit per second (symbol Mbit/s or Mb/s, often abbreviated "Mbps") is a unit of data transfer rate equal to:
Gigabit per second (symbol Gbit/s or Gb/s, often abbreviated "Gbps") is a unit of data transfer rate equal to:
Terabit per second (symbol Tbit/s or Tb/s, sometimes abbreviated "Tbps") is a unit of data transfer rate equal to:
These units are often not used in the suggested ways; see .
kilobyte per second (kB/s) (can be abbreviated as kBps) is a unit of data transfer rate equal to:
megabyte per second (MB/s) (can be abbreviated as MBps) is a unit of data transfer rate equal to:
gigabyte per second (GB/s) (can be abbreviated as GBps) is a unit of data transfer rate equal to:
terabyte per second (TB/s) (can be abbreviated as TBps) is a unit of data transfer rate equal to:
| Name | Symbol | bit per second | byte per second | bit per second(formula) | byte per second(formula) | |
|---|---|---|---|---|---|---|
| bit per second | bit/s | 1 | 0.125 | 1 | ||
| byte per second | B/s | 8 | 1 | 8 | 1 | |
| kilobit per second | kbit/s | 1,000 | 125 | 103 | × 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 | × 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 | × 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 | × 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 |
See main article: List of interface bit rates.
| 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 an ISDN B channel or best quality, uncompressed telephone line. | |
| data-sort-value="1536" | 1,536 | kbit/s | 1,536,000 | 192,000 | Networking | 24 channels of telephone in the US, or a good VTC T1. |
| data-sort-value="10000" | 10 | Mbit/s | 10,000,000 | 1,250,000 | Networking | 107 bit/s is the speed of classic Ethernet: 10BASE2, 10BASE5, 10BASE-T |
| data-sort-value="10000" | 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] |
| data-sort-value="54000" | 54 | Mbit/s | 54,000,000 | 6,750,000 | Networking | 802.11g, Wireless G LAN |
| data-sort-value="100000" | 100 | Mbit/s | 100,000,000 | 12,500,000 | Networking | Fast Ethernet |
| data-sort-value="600000" | 600 | Mbit/s | 600,000,000 | 75,000,000 | Networking | 802.11n, Wireless N LAN |
| data-sort-value="1000000" | 1 | Gbit/s | 1,000,000,000 | 125,000,000 | Networking | 1 Gigabit Ethernet |
| data-sort-value="10000000" | 10 | Gbit/s | 10,000,000,000 | 1,250,000,000 | Networking | 10 Gigabit Ethernet |
| data-sort-value="100000000" | 100 | Gbit/s | 100,000,000,000 | 12,500,000,000 | Networking | 100 Gigabit Ethernet |
| data-sort-value="1000000000" | 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) | |
| data-sort-value="2000" | 2 | Mbit/s | 2,000,000 | 250,000 | Video data | 30 channels of telephone audio or a Video Tele-Conference at VHS quality |
| data-sort-value="8000" | 8 | Mbit/s | 8,000,000 | 1,000,000 | Video data | DVD quality |
| data-sort-value="27000" | 27 | Mbit/s | 27,000,000 | 3,375,000 | Video data | HDTV quality |
| data-sort-value="1244000" | 1.244 | Gbit/s | 1,244,000,000 | 155,500,000 | Networking | OC-24, a 1.244 Gbit/s SONET data channel |
| data-sort-value="9953000" | 9.953 | Gbit/s | 9,953,000,000 | 1,244,125,000 | Networking | OC-192, a 9.953 Gbit/s SONET data channel |
| data-sort-value="39813000" | 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 |
| data-sort-value="4800000" | 60 | MB/s | 480,000,000 | 60,000,000 | Computer data interfaces | USB 2.0 High-Speed |
| data-sort-value="786432" | 98.3 | MB/s | 786,432,000 | 98,304,000 | Computer data interfaces | FireWire IEEE 1394b-2002 S800 |
| data-sort-value="960000" | 120 | MB/s | 960,000,000 | 120,000,000 | Computer data interfaces | Harddrive read, Samsung SpinPoint F1 HD103Uj[4] |
| data-sort-value="1064000" | 133 | MB/s | 1,064,000,000 | 133,000,000 | Computer data interfaces | Parallel ATA UDMA 6 |
| data-sort-value="1064000" | 133 | MB/s | 1,064,000,000 | 133,000,000 | Computer data interfaces | PCI 32-bit at 33 MHz (standard configuration) |
| data-sort-value="1504000" | 188 | MB/s | 1,504,000,000 | 188,000,000 | Computer data interfaces | SATA I 1.5 Gbit/s – First generation |
| data-sort-value="3000000" | 375 | MB/s | 3,000,000,000 | 375,000,000 | Computer data interfaces | SATA II 3 Gbit/s – Second generation |
| data-sort-value="4000000" | 500 | MB/s | 4,000,000,000 | 500,000,000 | Computer data interfaces | PCI Express x1 v2.0 |
| data-sort-value="5000000" | 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 |
| data-sort-value="6000000" | 750 | MB/s | 6,000,000,000 | 750,000,000 | Computer data interfaces | SATA III 6 Gbit/s – Third generation |
| data-sort-value="8533333" | 1,067 | MB/s | 8,533,333,333 | 1,066,666,667 | Computer data interfaces | PCI-X 64 bit 133 MHz |
| data-sort-value="10000000" | 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 |
| data-sort-value="10000000" | 1,250 | MB/s | 10,000,000,000 | 1,250,000,000 | Computer data interfaces | Thunderbolt |
| data-sort-value="20000000" | 2,500 | MB/s | 20,000,000,000 | 2,500,000,000 | Computer data interfaces | Thunderbolt 2 |
| data-sort-value="40000000" | 5,000 | MB/s | 40,000,000,000 | 5,000,000,000 | Computer data interfaces | Thunderbolt 3 |
| data-sort-value="64000000" | 8,000 | MB/s | 64,000,000,000 | 8,000,000,000 | Computer data interfaces | PCI Express x16 v2.0 |
| data-sort-value="96000000" | 12,000 | MB/s | 96,000,000,000 | 12,000,000,000 | Computer data interfaces | InfiniBand 12X QDR |
| data-sort-value="128000000" | 16,000 | MB/s | 128,000,000,000 | 16,000,000,000 | Computer data interfaces | PCI Express x16 v3.0 |