A gigabyte (GB) is 1,000 times larger than a megabyte (MB), which is 1 million bytes. A GB of data storage can store approximately 1 billion bytes. One minute of an MP3 audio file is about 1 MB, while the size of a DVD movie is roughly between 4 to 8 GB.
In 1998, the International Electrotechnical Commission (IEC) created standards for the amount of data represented by a gigabyte. The IEC requirement stipulated that a gigabyte must be equal to exactly 1,0003 bytes to differentiate it from a gibibyte, which represents 1,0243 bytes. The definition was incorporated into the International Standard of Quantities in 2009, and it is also recommended by the International System of Units (SI). However, some confusion remains because certain manufacturers measure storage capacity in gibibytes while using GB as the unit's abbreviation. In such a case, a hard drive advertised as 400 GB could be reported by an operating system as 372 GB.