Orders of magnitude (data)

The order of magnitude of data may be specified in strictly standards-conformant units of information and multiples of the bit and byte with decimal scaling, or using historically common usages of a few multiplier prefixes in a binary interpretation which has been common in computing until new binary prefixes were defined in the 1990s.

Units of measure

The byte has been a commonly used unit of measure for much of the information age to refer to a number of bits. In the early days of computing, it was used for differing numbers of bits based on convention and computer hardware design, but today means 8 bits. A more accurate, but less commonly used name for 8 bits is octet.

Commonly, a decimal SI metric prefix (such as kilo-) is used with bit and byte to express larger sizes (kilobit, kilobyte). But, this is usually inaccurate since these prefixes are decimal, whereas binary hardware size is usually binary. Customarily, each metric prefix, 1000ⁿ, is used to mean a close approximation of a binary multiple, 1024ⁿ. Often, this distinction is implicit, and therefore, use of metric prefixes can lead to confusion. The IEC binary prefixes (such as kibi-) allow for accurate description of hardware sizes, but are not commonly used.^[1][2]

Entropy

This page references two kinds of entropy which are not entirely equivalent. For comparison, the Avogadro constant is 6.02214076×10²³ entities per mole, based upon the number of atoms in 12 grams of carbon-12 isotope. See Entropy in thermodynamics and information theory.

• Entropy (information theory), such as the amount of information that can be stored in DNA
• Entropy (thermodynamics), such as entropy increase of 1 mole of water

List

Binary (bits)		Decimal		Item
Factor	Term	Factor	Term
2−1		10−1		0.415 bits (log2 4/3) – amount of information needed to eliminate one option out of four.
				0.6–1.3 bits – approximate information per letter of English text.[3]
20	bit	100	bit	1 bit – 0 or 1, false or true, Low or High (a.k.a. unibit)
				1.442695 bits (log2 e) – approximate size of a nat (a unit of information based on natural logarithms)
				1.5849625 bits (log2 3) – approximate size of a trit (a base-3 digit)
21				2 bits – a crumb (a.k.a. dibit) enough to uniquely identify one base pair of DNA
				3 bits – a triad(e), (a.k.a. tribit) the size of an octal digit
22	nibble			4 bits – (a.k.a. tetrad(e), nibble, quadbit, semioctet, or halfbyte) the size of a hexadecimal digit; decimal digits in binary-coded decimal form
				5 bits – the size of code points in the Baudot code, used in telex communication (a.k.a. pentad)
				6 bits – the size of code points in Univac Fieldata, in IBM "BCD" format, and in Braille. Enough to uniquely identify one codon of genetic code. The size of code points in Base64; thus, often the entropy per character in a randomly-generated password.
				7 bits – the size of code points in the ASCII character set – minimum length to store 2 decimal digits
23	byte (B)			8 bits – (a.k.a. octet or octad(e)) on many computer architectures. – equivalent to 1 "word" on 8-bit computers (Apple II, Atari 8-bit computers, Commodore 64, etc.). – the "word size" for 8-bit console systems including: Atari 2600, Nintendo Entertainment System
		101	decabit	10 bits – minimum bit length to store a single byte with error-correcting computer memory – minimum frame length to transmit a single byte with asynchronous serial protocols
				12 bits – wordlength of the PDP-8 of Digital Equipment Corporation (built from 1965 to 1990)
24				16 bits – the Basic Multilingual Plane of Unicode, containing character codings for almost all modern languages, and a large number of symbols – the basic unit in UTF-16; the full Universal Character Set (Unicode) can be encoded in one or two of these – commonly used in many programming languages, the size of an integer capable of holding 65,536 different values – equivalent to 1 "word" on 16-bit computers (IBM PC, Commodore Amiga) – the "word size" for 16-bit console systems including: Sega Genesis, Super Nintendo, Mattel Intellivision
25				32 bits (4 bytes) – size of an integer capable of holding 4,294,967,296 different values – size of an IEEE 754 single-precision floating point number – size of addresses in IPv4, the current Internet Protocol – equivalent to 1 "word" on 32-bit processors, including those for the Apple Macintosh, Pentium-based PC, PlayStation, GameCube, Xbox, Wii
				36 bits – size of word on Univac 1100-series computers and Digital Equipment Corporation's PDP-10
				56 bits (7 bytes) – cipher strength of the DES encryption standard
26				64 bits (8 bytes) – size of an integer capable of holding 18,446,744,073,709,551,616 different values – size of an IEEE 754 double-precision floating point number – equivalent to 1 "word" on 64-bit computers (Power, PA-RISC, Alpha, Itanium, SPARC, x86-64 PCs and Macintoshes). – the "word size" for 64-bit console systems including: Nintendo 64, PlayStation 2, PlayStation 3, Xbox 360
				80 bits (10 bytes) – size of an extended precision floating point number, for intermediate calculations that can be performed in floating point units of most processors of the x86 family.
		102	hectobit	100 bits
27				128 bits (16 bytes) – size of addresses in IPv6, the successor protocol of IPv4 – minimum cipher strength of the Rijndael and AES encryption standards, and of the widely used MD5 cryptographic message digest algorithm – size of an SSE vector register, included as part of the x86-64 standard
				160 bits (20 bytes) – maximum key length of the SHA-1, standard Tiger (hash function), and Tiger2 cryptographic message digest algorithms
28				256 bits (32 bytes) – minimum key length for the recommended strong cryptographic message digests as of 2004[update] – size of an AVX2 vector register, present on newer x86-64 CPUs
29				512 bits (64 bytes) – maximum key length for the standard strong cryptographic message digests in 2004 – size of an AVX-512 vector register, present on some x86-64 CPUs
		103	kilobit (kbit)	1,000 bits (125 bytes)
210	kibibit (Kibit)			1,024 bits (128 bytes) - RAM capacity of the Atari 2600
				1,288 bits (161 bytes) – approximate maximum capacity of a standard magnetic stripe card
211				2,048 bits (256 bytes) – RAM capacity of the stock Altair 8800
212				4,096 bits (512 bytes) – typical sector size, and minimum space allocation unit on computer storage volumes, with most file systems – approximate amount of information on a sheet of single-spaced typewritten paper (without formatting)
				4,704 bits (588 bytes) – uncompressed single-channel frame length in standard MPEG audio (75 frames per second and per channel), with medium quality 8-bit sampling at 44,100 Hz (or 16-bit sampling at 22,050 Hz)
			kilobyte (kB, KB)	8,000 bits (1,000 bytes)
213	kibibyte (KiB)			8,192 bits (1,024 bytes) – RAM capacity of a ZX81 and a ZX80.
				9,408 bits (1,176 bytes) – uncompressed single-channel frame length in standard MPEG audio (75 frames per second and per channel), with standard 16-bit sampling at 44,100 Hz
		104		15,360 bits – one screen of data displayed on an 8-bit monochrome text console (80x24)
214				16,384 bits (2 kibibytes) – one page of typed text,[4] RAM capacity of Nintendo Entertainment System
215				32,768 bits (4 kibibytes)
216				65,536 bits (8 kibibytes)
		105		100,000 bits
217				131,072 bits (16 kibibytes) – RAM capacity of the smallest ZX Spectrum.
218				262,144 bits (32 kibibytes) - RAM capacity of Matra Alice 90
				393,216 bits (48 kibibytes) - RAM capacity of 48K ZX Spectrum
				506 kilobits – approximate size of this article as of 20 May 2019
219				524,288 bits (64 kibibytes) – RAM capacity of popular 8-bit computers like the C-64, Amstrad CPC etc.
		106	megabit (Mbit)	1,000,000 bits
220	mebibit (Mibit)			1,048,576 bits (128 kibibytes) – RAM capacity of popular 8-bit computers like the C-128, Amstrad CPC etc. Or a 1024 x 768 pixel JPEG image.
				1,978,560 bits – a one-page, standard-resolution black-and-white fax (1728 × 1145 pixels)
221				2,097,152 bits (256 kibibytes)
				4,147,200 bits – one frame of uncompressed NTSC DVD video (720 × 480 × 12 bpp Y'CbCr)
222				4,194,304 bits (512 kibibytes)
				4,976,640 bits – one frame of uncompressed PAL DVD video (720 × 576 × 12 bpp Y'CbCr)
				5,000,000 bits – Typical English book volume in plain text format of 500 pages × 2000 characters per page and 5-bits per character.
				5,242,880 bits (640 kibibytes) – the maximum addressable memory of the original IBM PC architecture
			megabyte (MB)	8,000,000 bits (1,000 kilobytes) – the preferred definition of megabyte
				8,343,400 bits – one "typical" sized photograph with reasonably good quality (1024 × 768 pixels).
223	mebibyte (MiB)			8,388,608 bits (1,024 kibibytes), one of a few traditional meanings of megabyte
		107		11,520,000 bits – capacity of a lower-resolution computer monitor (as of 2006), 800 × 600 pixels, 24 bpp
				11,796,480 bits – capacity of a 3.5 in floppy disk, colloquially known as 1.44 megabyte but actually 1.44 × 1000 × 1024 bytes
224
				16,777,216 bits (2 mebibytes)
				25,000,000 bits – amount of data in a typical color slide
				30,000,000 bits – The first commercial harddisk IBM 350 in 1956 could store 3.75 MiB for a cost of US$50,000,[5] equivalent to $578,274 in 2024.
225				33,554,432 bits (4 mebibytes) – RAM capacity of stock Nintendo 64 and average size of a music track in MP3 format.
				41,943,040 bits (5 mebibytes) – approximate size of the Complete Works of Shakespeare[4]
				80,000,000 bits – In 1985 a 10 MB harddisk cost US$710,[5] equivalent to $2,076 in 2024.
				98,304,000 bits – capacity of a high-resolution computer monitor as of 2011, 2560 × 1600 pixels, 24 bpp
				50 – 100 megabits – amount of information in a typical phone book
226		108		67,108,864 bit (8 mebibytes)
227				134,217,728 bits (16 mebibytes)
				150 megabits – amount of data in a large foldout map
228				268,435,456 bits (32 mebibytes)
				144,000,000 bits: In 1980 an 18 MB hard disk cost US$4,199,[5] equivalent to $16,024 in 2024.
				423,360,000 bits: a five-minute audio recording, in CDDA quality
229				536,870,912 bits (64 mebibytes)
		109	gigabit (Gbit)	1,000,000,000 bits
230	gibibit (Gibit)			1,073,741,824 bits (128 mebibytes)
231				2,147,483,648 bits (256 mebibytes)
232				4,294,967,296 bits (512 mebibytes)
				5.45×109 bits (650 mebibytes) – capacity of a regular compact disc (CD)
				5.89×109 bits (702 mebibytes) – capacity of a large regular compact disc
				6.4×109 bits – capacity of the human genome (assuming 2 bits for each base pair)
				6,710,886,400 bits – average size of a movie in Divx format in 2002.[6]
			gigabyte (GB)	8,000,000,000 bits (1,000 megabytes) – In 1995 a 1 GB harddisk cost US$849,[5] equivalent to $1,752 in 2024.
233	gibibyte (GiB)			8,589,934,592 bits (1,024 mebibytes) – The maximum disk capacity using the 21-bit LBA SCSI standard introduced in 1979.
		1010		10,000,000,000 bits
234				17,179,869,184 bits (2 gibibytes). The storage limit of IDE standard for harddisks in 1986, also the volume size limit for the FAT16B file system (with 32 KiB clusters) released in 1987 as well as the maximum file size (2 GiB-1) in DOS operating systems prior to the introduction of large file support in DOS 7.10 (1997).
235				34,359,738,368 bits (4 gibibytes) – maximum addressable memory for the Motorola 68020 (1984) and Intel 80386 (1985), also the volume size limit for the FAT16B file system (with 64 KiB clusters) as well as the maximum file size (4 GiB-1) in MS-DOS 7.1-8.0.
				3.76×1010 bits (4.7 gigabytes) – capacity of a single-layer, single-sided DVD
236				68,719,476,736 bits (8 gibibytes)
				79,215,880,888 bits – 9.2 GiB size of Wikipedia article text compressed with bzip2 on 2013-06-05
		1011		100,000,000,000 bits
237				137,438,953,472 bits (16 gibibytes).
				1.46×1011 bits (17 gigabytes) – capacity of a double-sided, dual-layered DVD
				2.15×1011 bits (25 gigabytes) – capacity of a single-sided, single-layered 12-cm Blu-ray
238				274,877,906,944 bits (32 gibibytes)
239				549,755,813,888 bits (64 gibibytes)
		1012	terabit (Tbit)	1,000,000,000,000 bits
240	tebibit (Tibit)			1,099,511,627,776 bits (128 gibibytes) – estimated capacity of the Polychaos dubium genome, the largest known genome. The storage limit for ATA-1 compliant disks introduced in 1994.
				1.6×1012 bits (200 gigabytes) – capacity of a hard disk that would be considered average as of 2008[update]. In 2005 a 200 GB harddisk cost US$100,[5] equivalent to $161 in 2024. As of April 2015, this is the maximum capacity of a fingernail-sized microSD card.
241				2,199,023,255,552 bits (256 gibibytes) – As of 2017, this is the maximum capacity of a fingernail-sized microSD card
242				4,398,046,511,104 bits (512 gibibytes)
			terabyte (TB)	8,000,000,000,000 bits (1,000 gigabytes) – In 2010 a 1 TB hard disk cost US$80,[5] equivalent to $115 in 2024.
243	tebibyte (TiB)			8,796,093,022,208 bits (1,024 gibibytes)
		1013		10,000,000,000,000 bits (1.25 terabytes) – capacity of a human being's functional memory, according to Raymond Kurzweil in The Singularity Is Near, p. 126
				16,435,678,019,584 bits (1.9 terabytes) – Size of all multimedia files used in the English Wikipedia in May 2012
244				17,592,186,044,416 bits (2 tebibytes) – Maximum size of MBR partitions used in PCs introduced in 1983, also the maximum disk capacity using the 32-bit LBA SCSI introduced in 1987
245				35,184,372,088,832 bits (4 tebibytes)
246				70,368,744,177,664 bits (8 tebibytes)
		1014		100,000,000,000,000 bits
247				140,737,488,355,328 bits (16 tebibytes). NTFS volume capacity in Windows 7, Windows Server 2008 R2 or earlier implementation.[7]
				1.5×1014 bits (18.75 terabytes)
248				281,474,976,710,656 bits (32 tebibytes)
				(approximately) 4×1014 bits – as of 2022, data of π to the largest number of decimal digits ever calculated (1×1014).
249				562,949,953,421,312 bits (64 tebibytes)
		1015	petabit (Pbit)	1,000,000,000,000,000 bits
250	pebibit (Pibit)			1,125,899,906,842,624 bits (128 tebibytes)
251				2,251,799,813,685,248 bits (256 tebibytes)
252				4,503,599,627,370,496 bits (512 tebibytes)
			petabyte (PB)	8,000,000,000,000,000 bits (1,000 terabytes)
253	pebibyte (PiB)			9,007,199,254,740,992 bits (1,024 tebibytes)
		1016		10,000,000,000,000,000 bits
254				18,014,398,509,481,984 bits (2 pebibytes)
255				36,028,797,018,963,968 bits (4 pebibytes) – theoretical maximum of addressable physical memory in the AMD64 architecture [citation needed]
				4.5×1016 bits (5.625 petabytes) – estimated hard drive space in Google's server farm as of 2004[update] [citation needed]
256				72,057,594,037,927,936 bits (8 pebibytes)
				10 petabytes (1016 bytes) – estimated approximate size of the Library of Congress's collection, including non-book materials, as of 2005.[8] Size of the Internet Archive topped 10 PB in October 2013[9]
		1017		100,000,000,000,000,000 bits
257				144,115,188,075,855,872 bits (16 pebibytes)
				2×1017 bits (25 petabytes) – Storage space of Megaupload file-hosting service at the time it was shut down in 2012[10]
258				288,230,376,151,711,744 bits (32 pebibytes)
259				576,460,752,303,423,488 bits (64 pebibytes)
				8 ×1017, the storage capacity of the fictional Star Trek character Data
		1018	exabit (Ebit)	1,000,000,000,000,000,000 bits
260	exbibit (Eibit)			1,152,921,504,606,846,976 bits (128 pebibytes). The storage limit using the 48-bit LBA ATA-6 standard introduced in 2002.
				1.6×1018 bits (200 petabytes) – total amount of printed material in the world [citation needed]
				2×1018 bits (250 petabytes) – storage space at Facebook data warehouse as of June 2013,[11] growing at a rate of 15 PB/month.[12]
261				2,305,843,009,213,693,952 bits (256 pebibytes)
				2.4×1018 bits (300 petabytes) – storage space at Facebook data warehouse as of April 2014, growing at a rate of 0.6 PB/day.[13]
262				4,611,686,018,427,387,904 bits (512 pebibytes)
			exabyte (EB)	8,000,000,000,000,000,000 bits (1,000 petabytes)
263	exbibyte (EiB)			9,223,372,036,854,775,808 bits (1,024 pebibytes)
		1019		10,000,000,000,000,000,000 bits
264				18,446,744,073,709,551,616 bits (2 exbibytes).
265				36,893,488,147,419,103,232 bits (4 exbibytes)
				50,000,000,000,000,000,000 bits (50 exabit)
266				73,786,976,294,838,206,464 bits (8 exbibytes)
		1020		100,000,000,000,000,000,000 bits
				1.2×1020 bits (15 exabytes) – estimated storage space at Google data warehouse as of 2013[14]
267				147,573,952,589,676,412,928 bits (16 exbibytes) – maximum addressable memory using 64-bit addresses without segmentation.[15] Maximum file size for ZFS filesystem.
268				295,147,905,179,352,825,856 bits (32 exbibytes)
				3.5 × 1020 bits – increase in information capacity when 1 joule of energy is added to a heat-bath at 300 K (27 °C)[16]
269				590,295,810,358,705,651,712 bits (64 exbibytes)
		1021	zettabit (Zbit)	1,000,000,000,000,000,000,000 bits
270	zebibit (Zibit)			1,180,591,620,717,411,303,424 bits (128 exbibytes)
271				2,361,183,241,434,822,606,848 bits (256 exbibytes)
				3.4×1021 bits (0.36 zettabytes) – amount of information that can be stored in 1 gram of DNA[17]
				4.7×1021 bits (0.50 zettabytes) – amount of digitally stored information in the world as of May 2009[18]
				4.8×1021 bits (0.61 zettabytes) – total hard drive capacity shipped in 2016[19]
272				4,722,366,482,869,645,213,696 bits (512 exbibytes)
			zettabyte (ZB)	8,000,000,000,000,000,000,000 bits (1,000 exabytes)
273	zebibyte (ZiB)			9,444,732,965,739,290,427,392 bits (1,024 exbibytes)
		1022		10,000,000,000,000,000,000,000 bits
276				276 bits – Maximum volume and file size in the Unix File System (UFS) and maximum disk capacity using the 64-bit LBA SCSI standard introduced in 2000 using 512-byte blocks.[20]
		1023		1.0×1023 bits – increase in information capacity when 1 joule of energy is added to a heat-bath at 1 K (−272.15 °C)[21]
277				6.0×1023 bits – information content of 1 mole (12.01 g) of graphite at 25 °C; equivalent to an average of 0.996 bits per atom.[22]
		1024	yottabit (Ybit)	1,000,000,000,000,000,000,000,000 bits
				7.3×1024 bits – information content of 1 mole (18.02 g) of liquid water at 25 °C; equivalent to an average of 12.14 bits per molecule.[23]
280	yobibit (Yibit)			1,208,925,819,614,629,174,706,176 bits (128 zebibytes)
			yottabyte (YB)	8,000,000,000,000,000,000,000,000 bits (1,000 zettabytes)
283	yobibyte (YiB)			9,671,406,556,917,033,397,649,408 bits (1,024 zebibytes)
		1025		1.1×1025 bits – entropy increase of 1 mole (18.02 g) of water, on vaporizing at 100 °C at standard pressure; equivalent to an average of 18.90 bits per molecule.[24]
				1.5×1025 bits – information content of 1 mole (20.18 g) of neon gas at 25 °C and 1 atm; equivalent to an average of 25.39 bits per atom.[25]
286		1026
289		1027	ronnabit (Rbit)
293			ronnabyte (RB)
2100		1030	quettabit (Qbit)
2102			quettabyte (QB)
Beyond standardized SI / IEC (binary) prefixes
2127	N/A	1038	N/A	2127 bits, 2124 bytes – IBM Eagle
2131		1039		2131 bits, 2128 bytes – theoretical maximum volume size of the ZFS filesystem.[26][27][28]
2150		1042		~ 1042 bits – the number of bits required to perfectly recreate the natural matter of the average-sized U.S. adult male human brain down to the quantum level on a computer is about 2.6×1042 bits of information (see Bekenstein bound for the basis for this calculation).
2193		1058		~ 1058 bits – thermodynamic entropy of the sun[29] (about 30 bits per proton, plus 10 bits per electron).
2230		1069		~ 1069 bits – thermodynamic entropy of the Milky Way Galaxy (counting only the stars, not the black holes within the galaxy) [citation needed]
2255		1077		1.5×1077 bits – information content of a one-solar-mass black hole.[30]
2305		1090		The information capacity of the observable universe, according to Seth Lloyd (not including gravitation)[31]

See also

• Data-rate units
• List of interface bit rates
• Orders of magnitude (entropy)
• Unit prefix#Unofficial prefixes