Gigabyte

This article is about a multiple of bytes. For a binary unit of measurement, see gibibyte. For the company, see Gigabyte Technology. For other uses, see Gigabyte (disambiguation).

gigabyte
This 2.5-inch hard drive has a capacity of 500 gigabytes (GB) of data (i.e., 500 billion bytes).
General information
Unit system	Unit derived from bit
Unit of	Digital information, data size
Symbol	GB

Multiple-byte units

Decimal				Binary
Value		SI		Value		IEC		JEDEC
1000	103	kB	kilobyte	1024	210	KiB	kibibyte	KB	kilobyte
10002	106	MB	megabyte	10242	220	MiB	mebibyte	MB	megabyte
10003	109	GB	gigabyte	10243	230	GiB	gibibyte	GB	gigabyte
10004	1012	TB	terabyte	10244	240	TiB	tebibyte	TB	terabyte
10005	1015	PB	petabyte	10245	250	PiB	pebibyte	—
10006	1018	EB	exabyte	10246	260	EiB	exbibyte	—
10007	1021	ZB	zettabyte	10247	270	ZiB	zebibyte	—
10008	1024	YB	yottabyte	10248	280	YiB	yobibyte	—
10009	1027	RB	ronnabyte	10249	290	RiB	robibyte	—
100010	1030	QB	quettabyte	102410	2100	QiB	quebibyte	—
Orders of magnitude of data

The gigabyte (/ˈɡɪɡəbaɪt, ˈdʒɪɡəbaɪt/) is a multiple of the unit byte for digital information. The prefix giga- means 10⁹ in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte is GB.

This definition is used in all contexts of science (especially data science), engineering, business, and many areas of computing, including storage capacities of hard drives, solid-state drives, and tapes, as well as data transmission speeds. The term is also used in some fields of computer science and information technology to denote 1073741824 (1024³ or 2³⁰) bytes, however, particularly for sizes of RAM. Thus, some usage of gigabyte has been ambiguous. To resolve this, IEC 80000-13 states that a gigabyte (GB) is 10⁹ bytes and specifies the term gibibyte (GiB) to denote 2³⁰ bytes. These differences are still readily seen, for example, when a 400 GB drive's capacity is displayed by Microsoft Windows as 372 GB instead of 372 GiB. Analogously, a memory module that is labeled as having the size "1GB" has one gibibyte (1GiB) of storage capacity.

In response to litigation over whether the makers of electronic storage devices must conform to Microsoft Windows' use of a binary definition of "GB" instead of the metric/decimal definition, the United States District Court for the Northern District of California rejected that argument, ruling that "the U.S. Congress has deemed the decimal definition of gigabyte to be the 'preferred' one for the purposes of 'U.S. trade and commerce.'"