A gigabyte (GB) is a unit of digital information storage that equals 1,024 megabytes (MB). It is commonly used to measure the size of files, storage devices, and memory in computers and smartphones. For example, a typical high-definition movie might take up about 2 to 4 gigabytes of space. In the context of data transfer, a gigabyte can also represent the amount of data that can be sent or received over the internet. Many internet service providers offer plans with data limits measured in gigabytes, helping users understand their usage and manage their online activities effectively.