Data rate units

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).

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.

Pound sterling

The pound sterling (symbol: £; ISO code: GBP), commonly known simply as the pound, is the official currency of the United Kingdom, Jersey, Guernsey, the Isle of Man, South Georgia and the South Sandwich Islands, the British Antarctic Territory, and Tristan da Cunha. It is subdivided into 100 pence (singular: penny). A number of nations that do not use sterling also have currencies called the pound. At various times, the pound sterling was commodity money or bank notes backed by silver or gold, but it is currently fiat money, backed only by the economy in the areas where it is accepted. The pound sterling is the world's oldest currency still in use and which has been in continuous use since its inception.

The British Crown dependencies of Guernsey and Jersey produce their own local issues of sterling: "Guernsey pound" and "Jersey pound". The pound sterling is also used in the Isle of Man (alongside the Manx pound),Gibraltar (alongside the Gibraltar pound), the Falkland Islands (alongside the Falkland Islands pound), Saint Helena and Ascension Island in Saint Helena, Ascension and Tristan da Cunha (alongside the Saint Helena pound). The Bank of England is the central bank for the pound sterling, issuing its own coins and banknotes, and regulating issuance of banknotes by private banks in Scotland and Northern Ireland. Banknotes issued by other jurisdictions are not regulated by the Bank of England; local governments use Bank of England notes as backing for local issuance by allowing them to be exchanged 1:1 at face value.

Bit rate

In telecommunications and computing, bit rate (sometimes written bitrate or as a variable R) is the number of bits that are conveyed or processed per unit of time.

The bit rate is quantified using the bits per second unit (symbol: "bit/s"), often in conjunction with an SI prefix such as "kilo" (1 kbit/s = 1000 bit/s), "mega" (1 Mbit/s = 1000 kbit/s), "giga" (1 Gbit/s = 1000 Mbit/s) or "tera" (1 Tbit/s = 1000 Gbit/s). The non-standard abbreviation "bps" is often used to replace the standard symbol "bit/s", so that, for example, "1 Mbps" is used to mean one million bits per second.

One byte per second (1 B/s) corresponds to 8 bit/s.

Prefixes

When quantifying large bit rates, SI prefixes (also known as metric prefixes or decimal prefixes) are used, thus:

Binary prefixes are sometimes used for bit rates . The International Standard (IEC 80000-13) specifies different abbreviations for binary and decimal (SI) prefixes (e.g. 1 KiB/s = 1024 B/s = 8192 bit/s, and 1 MiB/s = 1024 KiB/s).

In data communications