Byte

A byte is a unit of measurement of the size of information on a computer or other electronic device. A single byte is usually eight bits. Some early computers used six bits for each byte. Bits are the smallest unit of storage on a computer, a single on/off value. Bytes are often represented by the capital letter B, bits by a lower case b.

A single typed character (for example, 'x' or '8') is stored in one byte. The character is held as a binary number which encodes a text character. To map each number to a character an agreed code such as EBCDIC or ASCII is needed. EBCDIC is a character encoding used mainly on mainframe computers. It uses 8 bits per byte. ASCII is another encoding that only uses seven bits. Extended ASCII uses 8 bits to give more types of characters, mostly used on personal computers.

The byte is the smallest useful unit of measure to show how many characters a computer (or electronics device) can hold. This is useful for things like RAM, or storage devices like USB drives and other types of Flash memory. Sending of data (for a modem or wi-fi) is usually measured in bits, not bytes.

On modern computers one byte is equal to eight bits. Some early computers used fewer bits for each byte. To tell them apart, computer scientists called an 8 bit byte an octet. In modern usage, an octet and a byte are the same.

Abbreviation

The symbol for "byte" is "B". Sometimes a lowercase "b" is used, but this use is incorrect because "b" is actually the IEEE symbol for "bit". The IEC symbol for bit is bit. For example, "MB" means "megabyte" and "Mbit" means "megabit". The difference is important because 1 megabyte (MB) is 1,000,000 bytes, and 1 megabit (Mbit) is 1,000,000 bits or 125,000 bytes. It's easy to confuse the two, but bits are much smaller than bytes, so the symbol "b" should be used when referring to "bits" and an uppercase "B" when referring to "bytes".

Names for larger units

For large data, byte is often used with a binary prefix:

Kilobyte/kibibyte (KB) (2¹⁰)
Megabyte/mebibyte (MB) (2²⁰)
Gigabyte/gibibyte (GB) (2³⁰)
Terabyte/tebibyte (TB) (2⁴⁰)

The following terms represent even larger units of bytes, but are very rarely used:

Petabyte/pebibyte (PB) (2⁵⁰)
Exabyte/exbibyte (EB) (2⁶⁰)
Zettabyte (ZB) (2⁷⁰)
Yottabyte (YB) (2⁸⁰)

Byte Chart

According to the International Electrotechnical Commission (IEC), who sets many computer standards, these charts show how bytes should be referred to.

People who refer to 1 kilobyte as 1,024 bytes, for example, are technically incorrect; 1,024 bytes should be referred to as 1 kibibyte, according to the IEC. ^[1] However, using 1024 for kilo and 1048576 for mega, etc. was widely practiced before the IEC standards were set in 1998. There is some confusion and mixing of terms in the marketplace. Computer memory is still referred to in powers of 2, so 1KB of memory is 1024 bytes, whereas in computer data storage powers of 10 are used, so 1KB is 1000 bytes.

"kilo-" = 1,000

When using standard metric names like "kilo-", "mega-" and "giga-", they should follow the same measure that other metric measurements use, like kilometer (1 kilometer = 1,000 meters), or gigahertz (1 gigahertz = 1,000,000,000 hertz) for example.

Unit	Number	Short scale	Long scale	Scientific,E Notation/ Power of 10
Byte (B)	1	1 byte	1 byte	1*10⁰,1E0 / 10⁰
Kilobyte (KB)	1,000	1 thousand bytes	1 thousand bytes	1*10³,1E3 / 10³
Megabyte (MB)	1,000,000	1 million bytes	1 million bytes	1*10⁶,1E6 / 10⁶
Gigabyte (GB)	1,000,000,000	1 billion bytes	1 billion bytes	1*10⁹,1E9 / 10⁹
Terabyte (TB)	1,000,000,000,000	1 trillion bytes	1 trillion bytes	1*10¹²,1E12 / 10¹²
Petabyte (PB)	1,000,000,000,000,000	1 quadrillion bytes	1 quadrillion bytes	1*10¹⁵,1E15 / 10¹⁵
Exabyte (EB)	1,000,000,000,000,000,000	1 quintillion bytes	1 quintillion bytes	1*10¹⁸,1E18 / 10¹⁸
Zettabyte (ZB)	1,000,000,000,000,000,000,000	1 sextillion bytes	1 sextillion bytes	1*10²¹,1E21 / 10²¹
Yottabyte (YB)	1,000,000,000,000,000,000,000,000	1 septillion bytes	1 septillion bytes	1*10²⁴,1E24 / 10²⁴
Brontobyte (BB) (unofficial)	1,000,000,000,000,000,000,000,000,000	1 octillion bytes	1 octillion bytes	1*10²⁷,1E27 / 10²⁷
Geopbyte (GpB/GeB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000	1 nonillion bytes	1 nonillion bytes	1*10³⁰,1E30 / 10³⁰
Saganbyte (SB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000	1 Decillion bytes	1 Decillion bytes	1*10³³,1E33 / 10³³
Pijabyte (PjB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000	1 Undecillion bytes	1 Undecillion bytes	1*10³⁶,1E36 / 10³⁶
Alphabyte (AB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Duodecillion bytes	1 Duodecillion bytes	1*10³⁹,1E39 / 10³⁹
Pectrolbyte (PcB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Tredecillion bytes	1 Tredecillion bytes	1*10⁴²,1E42 / 10⁴²
Bolgerbyte (BoB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Quattuordecillion bytes	1 Quattuordecillion bytes	1*10⁴⁵,1E45 / 10⁴⁵
Sambobyte (SaB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Quindecillion bytes	1 Quindecillion bytes	1*10⁴⁸,1E48 / 10⁴⁸
Quesabyte (QB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Sexdecillion bytes	1 Sexdecillion bytes	1*10⁵¹,1E51 / 10⁵¹
Kinsabyte (KiB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Septendecillion bytes	1 Septendecillion bytes	1*10⁵⁴,1E54 / 10⁵⁴
Rutherbyte (RB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Octodecillion bytes	1 Octodecillion bytes	1*10⁵⁷,1E57 / 10⁵⁷
Dubnibyte (DB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Novemdecillion bytes	1 Novemdecillion bytes	1*10⁶⁰,1E60 / 10⁶⁰
Hassiubyte (HaB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Vigintillion bytes	1 Vigintillion bytes	1*10⁶³,1E63 / 10⁶³
Meitnerbyte (MnB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Unvigintillion bytes	1 Unvigintillion bytes	1*10⁶⁶,1E66 / 10⁶⁶
Darmstadbyte (DrB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Duovigintillion bytes	1 Duovigintillion bytes	1*10⁶⁹,1E3 / 10⁶⁹
Roentbyte (RaB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Trevigintillion bytes	1 Trevigintillion bytes	1*10⁷²,1E3 / 10⁷²
Sophobyte (SoB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Quattuorvigintillion bytes	1 Quattuorvigintillion bytes	1*10⁷⁵,1E3 / 10⁷⁵
Coperbyte (CoB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Quinvigintillion bytes	1 Quinvigintillion bytes	1*10⁷⁸,1E78 / 10⁷⁸
Koentekbyte (KoB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Sexvigintillion bytes	1 Sexvigintillion bytes	1*10⁸¹,1E81 / 10⁸¹
Glossybyte (GsB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Septenvigintillion bytes	1 Septenvigintillion bytes	1*10⁸⁴,1E84 / 10⁸⁴
Snugbyte (SuB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Octovigintillion bytes	1 Octovigintillion bytes	1*10⁸⁷,1E87 / 10⁸⁷
Grandbyte (GrB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Nonvigintillion bytes	1 Nonvigintillion bytes	1*10⁹⁰,1E90 / 10⁹⁰
Doombyte (DmB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Trigintillion bytes	1 Trigintillion bytes	1*10⁹³,1E93 / 10⁹³
Godbyte (GdB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Untrigintillion bytes	1 Untrigintillion bytes	1*10⁹⁶,1E96 / 10⁹⁶
Superbyte (SpB) (unofficial)	1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Duotrigintillion bytes	1 Duotrigintillion bytes	1*10⁹⁹,1E99 / 10⁹⁹
Googolbyte (GgB) (unofficial)	10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000	1 Googol bytes	1 Googol bytes	1*10¹⁰⁰,1E100 / 10¹⁰⁰

"kibi-" = 1,024

Since computers are very complex digital devices that are based on the binary numeral system rather than the commonly-used decimal numeral system or binary coded decimal system, there are many situations where the standard metric system does not work well, particularly with memory sizes for a computer or storage device. If a memory or storage device uses a binary number for addresses, the number of different positions to be accessed (the size of the memory) can be expressed as a power of 2, rather than a power of 10.

Unit	Number	Maths
Byte (B)	1	2⁰ bytes
Kibibyte (KiB)	1,024	2¹⁰ bytes
Mebibyte (MiB)	1,048,576	2²⁰ bytes
Gibibyte (GiB)	1,073,741,824	2³⁰ bytes
Tebibyte (TiB)	1,099,511,627,776	2⁴⁰ bytes
Pebibyte (PiB)	1,125,899,906,842,624	2⁵⁰ bytes
Exbibyte (EiB)	1,152,921,504,606,846,976	2⁶⁰ bytes
Zebibyte (ZiB)	1,180,591,620,717,411,303,424	2⁷⁰ bytes
Yobibyte (YiB)	1,208,925,819,614,629,174,706,176	2⁸⁰ bytes
Bronbibyte (BiB) (unofficial)	1,237,940,039,285,380,274,899,124,224	2⁹⁰ bytes
Gebibyte (GeiB) (unofficial)	1,267,650,600,228,229,401,496,703,205,376	2¹⁰⁰ bytes
Sagbibyte (SiB) (unofficial)	1,298,074,214,633,706,907,132,624,082,305,024	2¹¹⁰ bytes
Pijbibyte (PjiB) (unofficial)	1,329,227,995,784,915,872,903,807,060,280,344,576	2¹²⁰ bytes
Alphbibyte (AiB) (unofficial)	1,361,129,467,683,753,853,853,498,429,727,072,845,824	2¹³⁰ bytes
Pectbibyte (PciB) (unofficial)	1,393,796,574,908,163,946,345,982,392,040,522,594,123,776	2¹⁴⁰ bytes
Bolgbibyte (BoiB) (unofficial)	1,427,247,692,705,959,881,058,285,969,449,495,136,382,746,624	2¹⁵⁰ bytes
Sambibyte (SaiB) (unofficial)	1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976	2¹⁶⁰ bytes
Quesbibyte (QiB) (unofficial)	1,496,577,676,626,844,588,240,573,268,701,473,812,127,674,924,007,424	2¹⁷⁰ bytes
Kinsbibyte (KiiB) (unofficial)	1,532,495,540,865,888,858,358,347,027,150,309,183,618,739,122,183,602,176	2¹⁸⁰ bytes
Ruthbibyte (RiB) (unofficial)	1,569,275,433,846,670,190,958,947,355,801,916,604,025,588,861,116,008,628,224	2¹⁹⁰ bytes
Dubbibyte (DiB) (unofficial)	1,606,938,044,258,990,275,541,962,092,341,162,602,522,202,993,782,792,835,301,376	2²⁰⁰ bytes
Hassbibyte (HaiB) (unofficial)	1,645,504,557,321,206,042,154,969,182,557,350,504,982,735,865,633,579,863,348,609,024	2²¹⁰ bytes
Meitbibyte (MniB) (unofficial)	1,684,996,666,696,914,987,166,688,442,938,726,917,102,321,526,408,785,780,068,975,640,576	2²²⁰ bytes
Darmbibyte (DriB) (unofficial)	1,725,436,586,697,640,946,858,688,965,569,256,363,112,777,243,042,596,638,790,631,055,949,824	2²³⁰ bytes
Roentbibyte (RaiB) (unofficial)	1,766,847,064,778,384,329,583,297,500,742,918,515,827,483,896,875,618,958,121,606,201,292,619,776	2²⁴⁰ bytes
Sophbibyte (SoiB) (unofficial)	1,809,251,394,333,065,553,493,296,640,760,748,560,207,343,510,400,633,813,116,524,750,123,642,650,624	2²⁵⁰ bytes
Copbibyte (CoiB) (unofficial)	1,852,673,427,797,059,126,777,135,760,139,006,525,652,319,754,650,249,024,631,321,344,126,610,074,238,976	2²⁶⁰ bytes
Koentbibyte (KoiB) (unofficial)	1,897,137,590,064,188,545,819,787,018,382,342,682,267,975,428,761,855,001,222,473,056,385,648,716,020,711,424	2²⁷⁰ bytes
Glossbibyte (GsiB) (unofficial)	1,942,668,892,225,729,070,919,461,906,823,518,906,642,406,839,052,139,521,251,812,409,738,904,285,205,208,498,176	2²⁸⁰ bytes
Snugbibyte (SuiB) (unofficial)	1,989,292,945,639,146,568,621,528,992,587,283,360,401,824,603,189,390,869,761,855,907,572,637,988,050,133,502,132,224	2²⁹⁰ bytes
Grandbibyte (GriB) (unofficial)	1,018,517,988,167,243,043,134,222,844,204,689,080,525,734,196,832,968,125,318,070,224,677,190,649,881,668,353,091,698,688	2²⁹⁹ bytes
Doombyte (DmiB) (unofficial)	1,042,962,419,883,256,876,169,444,192,465,601,618,458,351,817,556,959,360,325,703,910,069,443,225,478,828,393,565,899,456,512	2³⁰⁹ bytes
Godbibyte (GdiB) (unofficial)	1,067,993,517,960,455,041,197,510,853,084,776,057,301,352,261,178,326,384,973,520,803,911,109,862,890,320,275,011,481,043,468,288	2³¹⁹ bytes
Supbibyte (SpiB) (unofficial)	1,093,625,362,391,505,962,186,251,113,558,810,682,676,584,715,446,606,218,212,885,303,204,976,499,599,687,961,611,756,588,511,526,912	2³²⁹ bytes
Googolbibyte (GgiB) (unofficial)	1,119,872,371,088,902,105,278,721,140,284,222,139,060,822,748,617,324,767,449,994,550,481,895,935,590,080,472,690,438,746,635,803,557,888	2³³⁹ bytes

Byte Media

Percentage difference between decimal and binary interpretations of the unit prefixes grows with increasing storage size

References

↑ "official SI units for computers". NIST. Retrieved 4 April 2013.

This short article about technology can be made longer. You can help Wikipedia by adding to it.

[1] "official SI units for computers". NIST. Retrieved 4 April 2013.

[1]