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:

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

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
Byte

(B)

 1 1

byte

 1

byte

Kilobyte

(KB)

 1,000 1

thousand

bytes

 1

thousand

bytes

Megabyte (MB) 1,000,000 1

million

bytes

 1

million

bytes

Gigabyte (GB) 1,000,000,000 1

billion

bytes

 1

billion

bytes

Terabyte

(TB)

 1,000,000,000,000 1

trillion

bytes

 1

trillion

bytes

Petabyte

(PB)

 1,000,000,000,000,000 1

quadrillion

bytes

 1

quadrillion

bytes

Exabyte

(EB)

 1,000,000,000,000,000,000 1

quintillion

bytes

 1

quintillion

bytes

Zettabyte (ZB) 1,000,000,000,000,000,000,000 1

sextillion

bytes

 1

sextillion

bytes

Yottabyte (YB) 1,000,000,000,000,000,000,000,000 1

septillion

bytes

 1

septillion

bytes

Brontobyte (BB) (unofficial) 1,000,000,000,000,000,000,000,000,000 1

octillion

bytes

 1

octillion

bytes

Geopbyte (GpB/GeB) (unofficial) 1,000,000,000,000,000,000,000,000,000,000 1

nonillion

bytes

 1

nonillion

bytes

Saganbyte (SB) (unofficial) 1,000,000,000,000,000,000,000,000,000,000,000 1

Decillion

bytes

 1

Decillion

bytes

Pijabyte

(PjB) (unofficial)

 1,000,000,000,000,000,000,000,000,000,000,000,000 1

Undecillion

bytes

 1

Undecillion

bytes

Alphabyte (AB) (unofficial) 1,000,000,000,000,000,000,000,000,000,000,000,000,000 1

Duodecillion

bytes

 1

Duodecillion

bytes

Pectrolbyte (PcB) (unofficial) 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000 1

Tredecillion

bytes

 1

Tredecillion

bytes

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

"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

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