# Data rate units

Bit rates | |||
---|---|---|---|

Name | Symbol | Multiple | |

bit per second | bit/s | 1 | 1 |

Decimal prefixes (SI) | |||

kilobit per second | kbit/s | 10^{3} |
1000^{1} |

megabit per second | Mbit/s | 10^{6} |
1000^{2} |

gigabit per second | Gbit/s | 10^{9} |
1000^{3} |

terabit per second | Tbit/s | 10^{12} |
1000^{4} |

Binary prefixes (IEC 80000-13) | |||

kibibit per second | Kibit/s | 2^{10} |
1024^{1} |

mebibit per second | Mibit/s | 2^{20} |
1024^{2} |

gibibit per second | Gibit/s | 2^{30} |
1024^{3} |

tebibit per second | Tibit/s | 2^{40} |
1024^{4} |

In telecommunications, **data transfer rate** is the average number of bits (bitrate), characters or symbols (baudrate), or blocks 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) or kilobits per second (kbit/s).

## Contents

## 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. 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.

### Prefix

In both the SI and ISQ, the prefix k stands for kilo, meaning 1,000, while Ki is the symbol for the binary prefix kibi-, meaning 1,024. 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.

### 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 be 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:

- 1,000,000 bits per second
- 1,000 kilobits 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

### 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

## Binary multiples of bits

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

### Kibibit per second

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

- 1,024 bits per second

### Mebibit per second

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

- 1,048,576 bits per second
- 1,024 kibibits per second

### Gibibit per second

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

- 1,073,741,824 bits per second
- 1,048,576 kibibits per second
- 1,024 mebibits per second

### Tebibit per second

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

- 1,099,511,627,776 bits per second
- 1,073,741,824 kibibits per second
- 1,048,576 mebibits per second
- 1,024 gibibits per second

## Decimal multiples of bytes

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

### Kilobyte per second

**kilobyte per second** (**kB/s**) 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**) 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**) 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**) 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

## Binary multiples of bytes

### Kibibyte per second

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

- 1,024 bytes per second
- 8 kibibits per second
- 8192 bits per second

### Mebibyte per second

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

- 1,048,576 bytes per second
- 1,024 kibibytes per second
- 8 mebibits per second
- 8192 kibibits per second
- 8,388,608 bits per second

### Gibibyte per second

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

- 1,073,741,824 bytes per second
- 1,048,576 kibibytes per second
- 1,024 mebibytes per second
- 8 gibibits per second
- 8192 mebibits per second
- 8,388,608 kibibits per second
- 8,589,934,592 bits per second

### Tebibyte per second

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

- 1,099,511,627,776 bytes per second
- 1,073,741,824 kibibytes per second
- 1,048,576 mebibytes per second
- 1,024 gibibytes per second
- 8 tebibits per second
- 8192 gibibits per second
- 8,388,608 mebibits per second
- 8,589,934,592 kibibits per second
- 8,796,093,022,208 bits per second

## Conversion table

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 | 1/8 |

byte per second | B/s | 8 | 1 | 8 | 1 |

kilobit per second | kbit/s | 1,000 | 125 | 10^{3} |
10^{3}/8 |

kibibit per second | Kibit/s | 1,024 | 128 | 2^{10} |
2^{7} |

kilobyte per second | kB/s | 8,000 | 1,000 | 8x10^{3} |
10^{3} |

kibibyte per second | KiB/s | 8,192 | 1,024 | 2^{13} |
2^{10} |

megabit per second | Mbit/s | 1,000,000 | 125,000 | 10^{6} |
10^{6}/8 |

mebibit per second | Mibit/s | 1,048,576 | 131,072 | 2^{20} |
2^{17} |

megabyte per second | MB/s | 8,000,000 | 1,000,000 | 8x10^{6} |
10^{6} |

mebibyte per second | MiB/s | 8,388,608 | 1,048,576 | 2^{23} |
2^{20} |

gigabit per second | Gbit/s | 1,000,000,000 | 125,000,000 | 10^{9} |
10^{9}/8 |

gibibit per second | Gibit/s | 1,073,741,824 | 134,217,728 | 2^{30} |
2^{27} |

gigabyte per second | GB/s | 8,000,000,000 | 1,000,000,000 | 8x10^{9} |
10^{9} |

gibibyte per second | GiB/s | 8,589,934,592 | 1,073,741,824 | 2^{33} |
2^{30} |

terabit per second | Tbit/s | 1,000,000,000,000 | 125,000,000,000 | 10^{12} |
10^{12}/8 |

tebibit per second | Tibit/s | 1,099,511,627,776 | 137,438,953,472 | 2^{40} |
2^{37} |

terabyte per second | TB/s | 8,000,000,000,000 | 1,000,000,000,000 | 8x10^{12} |
10^{12} |

tebibyte per second | TiB/s | 8,796,093,022,208 | 1,099,511,627,776 | 2^{43} |
2^{40} |

## Examples of bit rates

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

56 | kbit/s | 56,000 | 7,000 | Networking | 56kbit modem – 56 kbit/s – 56,000 bit/s |

64 | kbit/s | 64,000 | 8,000 | Networking | 64kbit/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 | 10^{7} 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. 10^{7} bit/sec^{[1]}^{[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 |

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^{[2]} |

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^{[3]} |

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 3Gbit/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 |

1067 | 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 |

1250 | MB/s | 10,000,000,000 | 1,250,000,000 | Computer data interfaces | Thunderbolt |

2500 | MB/s | 20,000,000,000 | 2,500,000,000 | Computer data interfaces | Thunderbolt 2 |

8000 | MB/s | 64,000,000,000 | 8,000,000,000 | Computer data interfaces | PCI Express x16 v2.0 |

12000 | MB/s | 96,000,000,000 | 12,000,000,000 | Computer data interfaces | InfiniBand 12X QDR |

16000 | MB/s | 128,000,000,000 | 16,000,000,000 | Computer data interfaces | PCI Express x16 v3.0 |

## See also

- Binary prefix
- Bit rate
- List of device bandwidths
- Orders of magnitude (bit rate)
- Orders of magnitude (data)
- SI prefix

## Notes

- ↑ Penn researchers calculate how much the eye tells the brain, 26 July 2006
- ↑ "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.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - ↑ "Samsung overtakes".<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>

## References

- International Electrotechnical Commission (2007). "Prefixes for binary multiples". Retrieved on 2007-05-06.
- IEC 60027-2 "Letter symbols to be used in electrical technology – Part 2: Telecommunications and electronics+
- Donald Knuth: "What is a kilobyte?"