Two gigabytes is equal to 2,000 megabytes. However, GB has historically been used in the fields of computer science and information technology to refer to 1,073,741,824 bytes. This is now known as the gibibyte (GiB), a binary multiple approximately equal to 1,074 megabytes, or 1,024 mebibytes (MiB).
Though the U.S. National Institute of Standards and Technology has endorsed the binary prefixes as the official standard, it has seen limited usage. Computer memory manufacturers commonly refer to 1,024 megabytes as a gigabyte, whereas manufacturers of storage devices tend to use gigabyte strictly to describe 1,000 megabytes. Due to the lack of a standard system, 2 GB can realistically be equal to either 2,000 MB or 2,048 MB.