A unit of digital information, the Gigabyte (GB) is a multiple of the byte, the basic unit of digital storage. The prefix giga- means 109 in the International System of Units (SI). Therefore, one GB is one billion bytes. The GB is used in all contexts of science (especially data science), engineering, business, and many areas of computing.
Data Storage and Transmission
The GB is commonly used to measure storage capacities of hard drives, solid-state drives, and tapes, as well as data transmission speeds.
- Storage capacities: The GB is used to describe the amount of data that can be stored on a device, such as a hard drive or a solid-state drive. For example, a 400 GB drive can store up to 400 billion bytes of data.
- Data transmission speeds: The GB is also used to measure the speed of data transmission, such as the speed of an internet connection or the speed of a data transfer between two devices.
Ambiguity and Standardization
The term GB has been ambiguous in some fields of computer science and information technology, where it has been used to denote 1073741824 (10243 or 230) bytes, particularly for sizes of RAM. To resolve this, IEC 80000-13 states that a GB is 109 bytes and specifies the term gibibyte (GiB) to denote 230 bytes.
Table: GB vs. GiB
| Unit | Symbol | Value in Bytes |
| Gigabyte | GB | 109 |
| Gibibyte | GiB | 230 |
Binary and Decimal Systems
The GB is based on the decimal system, where each prefix represents a power of 10. However, in computing, the binary system is often used, where each prefix represents a power of 2. This can lead to confusion when comparing storage capacities or data transmission speeds.
- Decimal system: In the decimal system, the prefix giga- represents 109, or one billion. Therefore, one GB is one billion bytes.
- Binary system: In the binary system, the prefix giga- represents 230, or 1,073,741,824. Therefore, one GiB is 1,073,741,824 bytes.
