Definition: A gigabyte (GB) is equal to 109 bytes (10003 bytes), where a byte is a unit of digital information that consists of eight bits (binary digits).

History/origin: The gigabyte is based on the byte, which is derived from the bit, and is a unit that makes use of SI (International System of Units) prefixes. The gigabyte is most commonly understood in terms of its decimal definition of 10003 bytes. There is also however, a binary definition where a gigabyte is 10243 bytes. Because this can be the source of confusion, in 1998, the International Electrotechnical Commission published standards that required the gigabyte strictly denote 10003 bytes. Prefixes to denote the byte being based on 1024 rather than 1000 were also created, with gibibyte referencing 10243 bytes. Despite this effort, the gigabyte is still often used to signify either of these definitions.

Current use: The unit of bytes and all its multiples are used worldwide for data storage. Computer files, hard disks, Blu-ray discs, video games, etc. all store or contain storage space referenced in byte multiples such as kilobytes, megabytes, or gigabytes.