Unit of Digital Information Storage
Gigabyte	109 Bytes 1000 Megabytes
SI	IEC
Decimal	Binary
kilobyte kB 103 megabyte MB 106 gigabyte GB 109 terabyte TB 1012 petabyte PB 1015 exabyte EB 1018 zettabyte ZB 1021 yottabyte YB 1024	kibibyte KiB 210 mebibyte MiB 220 gibibyte GiB 230 tebibyte TiB 240 pebibyte PiB 250 exbibyte EiB 260 zebibyte ZiB 270 yobibyte YiB 280
(larger units were proposed but have not yet formally been adopted by the BIPM)

A gigabyte (GB) is an International System of Units (SI) unit of digital information storage equal to 1000 megabytes. This unit is part of IEC 80000-13 (International System of Quantities) which requires this unit to always equal 1000 megabytes. A closely related unit, gibibyte, is used to represent 1024 mebibytes.