Data rate units
Encyclopedia
In telecommunications, bit rate
Bit rate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....

or data transfer rate is the average number of bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

s, characters, or blocks per unit time passing between equipment in a data transmission system. This is typically measured in multiples of the unit
Units of measurement
A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of...

bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

per second or byte
Octet (computing)
An octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, as there is no standard for the size of the byte.-Overview:...

per second.

## Avoiding confusion

To be as explicit as possible, both the prefix and the suffix of the unit must be known. For example, the abbreviation 2 Mb can actually be expanded in 2 different ways (mega- vs mebi- and -bit). The difference in the associated numbers can be significant:
Unit Bits Bits / 1,000,000
Mega-bit 1,000,000 1.0
Mebi-bit 1,048,576 1.05
Mega-byte 8,000,000 8.0
Mebi-byte 8,388,608 8.39

The table above shows an approximate 5% difference between the corresponding mega- and mebi- units with a 800% difference between -bit and -byte units. Explicitness in units is important because difference can become even larger across different prefix units).

### Prefix: k vs Ki

k- stands for kilo, meaning 1,000, while Ki- stands for kilobinary ("kibi-"), meaning 1,024. The standardized binary prefixes
Binary prefix
In computing, a binary prefix is a specifier or mnemonic that is prepended to the units of digital information, the bit and the byte, to indicate multiplication by a power of 2...

such as Ki- were relatively recently introduced and still face low adoption. K- is often used to mean 1,024, especially in KB, the kilobyte
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...

.

### Suffix: b vs B

b stands for bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

and B stands for byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...

. In the context of data rate units, one byte refers to 8 bits
Octet (computing)
An octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, as there is no standard for the size of the byte.-Overview:...

. For example, when a 1 Mbps connection is advertised, it usually means that the maximum achievable download bandwidth is 1 megabit/s (million bits per second), which is actually 0.125 MB/s (megabyte per second), or about 0.1192 MiB/s (mebibyte per second).

### Problems

In 1999, the International Electrotechnical Commission (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.

The correct use for file, disk, and memory size is as follows:
Unit (SI
SI prefix
The International System of Units specifies a set of unit prefixes known as SI prefixes or metric prefixes. An SI prefix is a name that precedes a basic unit of measure to indicate a decadic multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol...

)
Bytes Unit (IEC 60027-2) Bytes
Kilobyte (kB) 1,000 Kibibyte (KiB) 1,024
Megabyte (MB) 1,0002 Mebibyte (MiB) 1,0242
Gigabyte (GB) 1,0003 Gibibyte (GiB) 1,0243
Terabyte (TB) 1,0004 Tebibyte (TiB) 1,0244
Petabyte (PB) 1,0005 Pebibyte (PiB) 1,0245

Computer and technology industries have yet to adapt to these standards. When Microsoft Windows shows the size of a drive or a file, it uses powers of 1,024 but uses SI prefixes so that, for example, 28,735,078,400 bytes displays as 26.7 GB instead of either 28.7 GB, or 26.7 GiB.

The commonly advertised (formatted) capacity of the 3.5-inch floppy disk was 1.44 MB but was actually 1,440 KiB or 1.44 × 1,000 × 1,024 bytes, giving either 1.41 MiB or 1.47 MB.

On September 18, 2003, Reuters reported that Apple, Dell, Gateway, Hewlett-Packard, IBM, Sharp, Sony, and Toshiba were being sued in a class-action law-suit in the Los Angeles Superior Court for "deceiving" buyers as to the true capacity of those companies' hard drives. This of course was due to ambiguity of GB when used by software and hardware vendors.

### Kilobit per second

A kilobit per second (kbit/s, kb/s, or kbps) is a unit of data transfer rate equal to:
• 1000 bits per second or
• 125 bytes per second.

### Megabit per second

A megabit per second (Mbit/s, Mb/s, or Mbps; not to be confused with mbit/s which means, literally, millibit per second) is a unit of data transfer rate equal to:
• 1,000,000 bits per second or
• 1,000 kilobit
Kilobit
The kilobit is a multiple of the unit bit for digital information or computer storage. The prefix kilo is defined in the International System of Units as a multiplier of 103 , and therefore,...

s per second or
• 125,000 bytes per second.

### Gigabit per second

A gigabit per second (Gbit/s, Gb/s, or Gbps) is a unit of data transfer rate equal to:
• 1,000 megabit
Megabit
The megabit is a multiple of the unit bit for digital information or computer storage. The prefix mega is defined in the International System of Units as a multiplier of 106 , and therefore...

s per second or
• 1,000,000 kilobits per second or
• 1,000,000,000 bits per second or
• 125,000,000 bytes per second

## Binary multiples of bits

### Kibibit per second

A kibibit per second (Kibit/s or Kib/s) is a unit of data transfer rate equal to 1,024 bits per second. The word "kibibit" is not capitalized, but the abbreviation "Kibits" is.

### Mebibit per second

A mebibit per second (Mibit/s or Mib/s) is a unit of data transfer rate equal to:
• 1,048,576 bits per second or
• 1,024 kibibit
Kibibit
The kibibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier kibi , a binary prefix meaning 210...

s per second.

### Gibibit per second

A gibibit per second (Gibit/s or Gib/s) is a unit of data transfer rate equal to:
• 1,073,741,824 bits per second or
• 1,048,576 kibibits per second or
• 1,024 mebibit
Mebibit
The mebibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier mebi , a binary prefix meaning 220...

s per second.

### Tebibit per second

A tebibit per second (Tibit/s or Tib/s) is a unit of data transfer rate equal to:
• 1,099,511,627,776 bits per second or
• 1,073,741,824 kibibits per second or
• 1,048,576 mebibits per second or
• 1,024 gibibit
Gibibit
The gibibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier gibi , a binary prefix meaning 230. The unit symbol of the gibibit is Gibit or Gib....

s per second.

## Decimal multiples of bytes

WARNING: These units are often not used in the suggested ways! See section above, "Problems".

### Kilobyte per second

A kilobyte per second (KB/s, KBps, kB/s, or kBps) is a unit of data transfer rate equal to:
• 8,000 bits per second, or
• 1,000 bytes per second, or
• 8 kilobits per second.

### Megabyte per second

(not to be confused with Mbps - Mega bits per second)
A megabyte per second (MB/s or MBps) is a unit of data transfer rate equal to:
• 8,000,000 bits per second, or
• 1,000,000 bytes per second, or
• 1,000 kilobytes per second, or
• 8 megabits per second.

### Gigabyte per second

A gigabyte per second (GB/s or GBps) is a unit of data transfer rate equal to:
• 8,000,000,000 bits per second, or
• 1,000,000,000 bytes per second, or
• 1,000,000 kilobytes per second, or
• 1,000 megabytes per second, or
• 8 gigabits per second.

### Terabyte per second

A terabyte per second (TB/s or TBps) is a unit of data transfer rate equal to:
• 8,000,000,000,000 bits per second, or
• 1,000,000,000,000 bytes per second, or
• 1,000,000,000 kilobytes per second, or
• 1,000,000 megabytes per second, or
• 1,000 gigabytes per second, or
• 8 terabit
Terabit
The terabit is a multiple of the unit bit for digital information or computer storage. The prefix tera is defined in the International System of Units as a multiplier of 1012 , and therefore...

s per second.

## Binary multiples of bytes

### Kibibyte per second

A kibibyte per second (KiB/s or KiBps) is a unit of data transfer rate equal to:
• 1,024 bytes per second, or
• 8 kibibits per second, or
• 8192 bits per second.

### Mebibyte per second

A mebibyte per second (MiB/s or MiBps) is a unit of data transfer rate equal to:
• 1,048,576 bytes per second, or
• 1,024 kibibyte
Kibibyte
The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission in 1999 and has been accepted for use...

s per second, or
• 8 mebibits per second, or
• 8192 kibibits per second, or
• 8,388,608 bits per second.

### Gibibyte per second

A gibibyte per second (GiB/s or GiBps) is a unit of data transfer rate equal to:
• 1,073,741,824 bytes per second, or
• 1,048,576 kibibytes per second, or
• 1,024 mebibyte
Mebibyte
The mebibyte is a multiple of the unit byte for digital information. The binary prefix mebi means 220, therefore 1 mebibyte is . The unit symbol for the mebibyte is MiB. The unit was established by the International Electrotechnical Commission in 2000 and has been accepted for use by all major...

s per second, or
• 8 gibibits per second, or
• 8192 mebibits per second, or
• 8,388,608 kibibits per second, or
• 8,589,934,592 bits per second.

### Tebibyte per second

A tebibyte per second (TiB/s or TiBps) is a unit of data transfer rate equal to:
• 1,099,511,627,776 bytes per second, or
• 1,073,741,824 kibibytes per second, or
• 1,048,576 mebibytes per second, or
• 1,024 gibibyte
Gibibyte
The gibibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The gibibyte unit symbol is GiB....

s per second, or
• 8 tebibit
Tebibit
The tebibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier tebi , a binary prefix meaning 240...

s per second.
• 8192 gibibits per second, or
• 8,388,608 mebibits per second, or
• 8,589,934,592 kibibits per second, or
• 8,796,093,022,208 bits per second.

## Conversion formula

Name Symbol bit per second byte per second bit per second (formula) byte per second (formula)
bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

per second
bit/s 1 0.125 1 1/8
byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...

per second
B/s 8 1 8 1
kilobit
Kilobit
The kilobit is a multiple of the unit bit for digital information or computer storage. The prefix kilo is defined in the International System of Units as a multiplier of 103 , and therefore,...

per second
kbit/s 1,000 125 103 103/8
kibibit
Kibibit
The kibibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier kibi , a binary prefix meaning 210...

per second
Kibit/s 1,024 128 210 27
kilobyte
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...

per second
kB/s 8,000 1,000 8x103 103
kibibyte
Kibibyte
The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission in 1999 and has been accepted for use...

per second
KiB/s 8,192 1,024 213 210
megabit
Megabit
The megabit is a multiple of the unit bit for digital information or computer storage. The prefix mega is defined in the International System of Units as a multiplier of 106 , and therefore...

per second
Mbit/s 1,000,000 125,000 106 106/8
mebibit
Mebibit
The mebibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier mebi , a binary prefix meaning 220...

per second
Mibit/s 1,048,576 131,072 220 217
megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...

per second
MB/s 8,000,000 1,000,000 8x106 106
mebibyte
Mebibyte
The mebibyte is a multiple of the unit byte for digital information. The binary prefix mebi means 220, therefore 1 mebibyte is . The unit symbol for the mebibyte is MiB. The unit was established by the International Electrotechnical Commission in 2000 and has been accepted for use by all major...

per second
MiB/s 8,388,608 1,048,576 223 220
gigabit
Gigabit
The gigabit is a multiple of the unit bit for digital information or computer storage. The prefix giga is defined in the International System of Units as a multiplier of 109 , and therefore...

per second
Gbit/s 1,000,000,000 125,000,000 109 109/8
gibibit
Gibibit
The gibibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier gibi , a binary prefix meaning 230. The unit symbol of the gibibit is Gibit or Gib....

per second
Gibit/s 1,073,741,957 134,217,728 230 227
gigabyte
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...

per second
GB/s 8,000,000,000 1,000,000,000 8x109 109
gibibyte
Gibibyte
The gibibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The gibibyte unit symbol is GiB....

per second
GiB/s 8,589,934,592 1,073,741,824 233 230
terabit
Terabit
The terabit is a multiple of the unit bit for digital information or computer storage. The prefix tera is defined in the International System of Units as a multiplier of 1012 , and therefore...

per second
Tbit/s 1,000,000,000,000 125,000,000,000 1012 1012/8
tebibit
Tebibit
The tebibit is a multiple of the bit, a unit of digital information storage, prefixed by the standards-based multiplier tebi , a binary prefix meaning 240...

per second
Tibit/s 1,099,511,627,776 137,438,953,472 240 237
terabyte
Terabyte
The terabyte is a multiple of the unit byte for digital information. The prefix tera means 1012 in the International System of Units , and therefore 1 terabyte is , or 1 trillion bytes, or 1000 gigabytes. 1 terabyte in binary prefixes is 0.9095 tebibytes, or 931.32 gibibytes...

per second
TB/s 8,000,000,000,000 1,000,000,000,000 8x1012 1012
tebibyte
Tebibyte
The tebibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The tebibyte unit symbol is TiB....

per second
TiB/s 8,796,093,022,208 1,099,511,627,776 243 240

## Examples

Quantity Unit bits per second bytes per second Field Description
56 kbit/s 56,000 7,000 Networking 56k modem
56K modem
56k modems are voiceband modems nominally capable of download speeds up to 56 kbit/s . In the late 1990s, they were the most popular access method for personal Internet usage, but their use had declined as broadband technologies such as DSL gained wider availability.-Speed:The 56 kbit/s...

– 56 kb/s – 56,000 b/s
64 kbit/s 64,000 8,000 Networking 64k ISDN – 64 kb/s – 64,000 b/s
1536 kbit/s 1,536,000 192,000 Networking 1536k T1
Digital Signal 1
Digital signal 1 is a T-carrier signaling scheme devised by Bell Labs. DS1 is a widely used standard in telecommunications in North America and Japan to transmit voice and data between devices. E1 is used in place of T1 outside North America, Japan, and South Korea...

– 1,536,000 b/s (1.536 Mb/s)
1 Gbit/s 1,000,000,000 125,000,000 Networking Gigabit Ethernet
Gigabit Ethernet
Gigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second , as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks where it performed...

10 Gbit/s 10,000,000,000 1,250,000,000 Networking 10 Gigabit Ethernet
10 Gigabit Ethernet
The 10 gigabit Ethernet computer networking standard was first published in 2002. It defines a version of Ethernet with a nominal data rate of 10 Gbit/s , ten times faster than gigabit Ethernet.10 gigabit Ethernet defines only full duplex point to point links which are generally connected by...

1 Tbit/s 1,000,000,000,000 125,000,000,000 Networking SEA-ME-WE 4 submarine communications cable
Submarine communications cable
A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean....

– 1.28 terabits per second
4 kbit/s 4,000 500 Audio data minimum achieved for encoding recognizable speech (using special-purpose speech codecs
Speech encoding
Speech coding is the application of data compression of digital audio signals containing speech. Speech coding uses speech-specific parameter estimation using audio signal processing techniques to model the speech signal, combined with generic data compression algorithms to represent the resulting...

)
8 kbit/s 8,000 1,000 Audio data telephone
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

quality
32 kbit/s 32,000 4,000 Audio data MW quality
128 kbit/s 128,000 16,000 Audio data 128 kb/s MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

– 128,000 b/s
192 kbit/s 192,000 24,000 Audio data Nearly CD quality for a file compressed in the MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

format
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 VHS
VHS
The Video Home System is a consumer-level analog recording videocassette standard developed by Victor Company of Japan ....

quality
8 Mbit/s 8,000,000 1,000,000 Video data DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

quality
27 Mbit/s 27,000,000 3,375,000 Video data HDTV
High-definition television
High-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...

quality
1.244 Gbit/s 1,244,000,000 155,500,000 Networking OC-24, a 1.244 Gb/s SONET
Sonet
Sonet may refer to:* Sonet Records, European record label* Synchronous optical networking * Saab Sonett...

data channel
9.953 Gbit/s 9,953,000,000 1,244,125,000 Networking OC-192, a 9.953 Gb/s SONET
Sonet
Sonet may refer to:* Sonet Records, European record label* Synchronous optical networking * Saab Sonett...

data channel
39.813 Gbit/s 39,813,000,000 4,976,625,000 Networking OC-768, a 39.813 Gb/s SONET
Sonet
Sonet may refer to:* Sonet Records, European record label* Synchronous optical networking * Saab Sonett...

data channel, the fastest in current use
60 MB/s 480,000,000 60,000,000 Computer data interfaces USB 2.0
625 MB/s 5,000,000,000 625,000,000 Computer data interfaces USB 3.0
USB 3.0
USB 3.0 is the second major revision of the Universal Serial Bus standard for computer connectivity.USB 3.0 has transmission speeds of up to 5 Gbit/s, which is 10 times faster than USB 2.0 . USB 3.0 significantly reduces the time required for data transmission, reduces power consumption, and...

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
133 MB/s 1,064,000,000 133,000,000 Computer data interfaces PATA
AT Attachment
Parallel ATA , originally ATA, is an interface standard for the connection of storage devices such as hard disks, solid-state drives, floppy drives, and optical disc drives in computers. The standard is maintained by X3/INCITS committee...

33 – 133 MB/s
188 MB/s 1,200,000,000 150,000,000 Computer data interfaces SATA
Serial ATA
Serial ATA is a computer bus interface for connecting host bus adapters to mass storage devices such as hard disk drives and optical drives...

1.5Gb/s – First generation
375 MB/s 2,400,000,000 300,000,000 Computer data interfaces SATA
Serial ATA
Serial ATA is a computer bus interface for connecting host bus adapters to mass storage devices such as hard disk drives and optical drives...

3Gb/s – Second generation
750 MB/s 4,800,000,000 600,000,000 Computer data interfaces SATA
Serial ATA
Serial ATA is a computer bus interface for connecting host bus adapters to mass storage devices such as hard disk drives and optical drives...

6Gb/s – Third generation
533 MB/s 4,264,000,000 533,000,000 Computer data interfaces PCI
Peripheral Component Interconnect
Conventional PCI is a computer bus for attaching hardware devices in a computer...

133 – 533 MB/s
1250 MB/s 10,000,000,000 1,250,000,000 Computer data interfaces Thunderbolt
8000 MB/s 64,000,000,000 8,000,000,000 Computer data interfaces PCI Express x16 v2.0
PCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...

12000 MB/s 96,000,000,000 12,000,000,000 Computer data interfaces InfiniBand 12X QDR
InfiniBand
InfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...

## See also

• Binary prefix
Binary prefix
In computing, a binary prefix is a specifier or mnemonic that is prepended to the units of digital information, the bit and the byte, to indicate multiplication by a power of 2...

• Bit rate
Bit rate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....

• List of device bandwidths
• Orders of magnitude (data)
Orders of magnitude (data)
An order of magnitude is generally a factor of ten. A quantity growing by four orders of magnitude implies it has grown by a factor of 10000 or 104. However, because computers are binary, orders of magnitude are sometimes given as powers of two....

• SI prefix
SI prefix
The International System of Units specifies a set of unit prefixes known as SI prefixes or metric prefixes. An SI prefix is a name that precedes a basic unit of measure to indicate a decadic multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.