gigabyte (GB)

Contributor(s): Sarah Wilson

A gigabyte (GB) is a measure of computer data storage capacity that is roughly equivalent to 1 billion bytes. A gigabyte is two to the 30th power or 1,073,741,824 in decimal notation. The term is pronounced with two hard Gs. The prefix giga comes from a Greek word meaning giant.

There are two standards for measuring the number of bytes in a gigabyte: base-10 and base-2. The base-10 definition of gigabyte uses the decimal system to show that 1 GB is equal to one to the 10th power of bytes, or 1 billion bytes. This is the standard most storage manufacturers and consumers use today.

Computers typically use the binary form of measurement, referred to as base-2. Base-2 measures 1 GB as equal to 1,073,741,824 bytes. Gigabytes are sometimes referred to as gibibytes in this model. While the discrepancy between base-10 and base-2 measurements wasn't substantial at first, it became more pronounced as vendors began manufacturing storage media with more capacity and caused for some confusion among consumers.

Base-2 vs. Base-10 definition

Gigabyte-size storage options and pricing

There are a number of types of storage media available that provide capacity in the gigabyte range, and those capacities can vary drastically. Some of the most commonly used storage types that provide capacity in this range are hard disk drives (HDDs), flash drives and DVDs. Today, 1 GB translates to approximately 200 songs or 250 10-megapixel photos. Most personal, removable storage devices have capacities ranging from 8 GB to 128 GB.

Cost of a GB of storage

Cost per gigabyte varies among vendors and types of storage media. The cost per gigabyte is higher on a flash drive than it is on a HDD. However, the cost per gigabyte across all vendors and storage types generally lowers year over year. The average price per gigabyte of a HDD in 2005, for example, was $1.24, while in 2014 the price dropped to 3 cents.

Also see gigabit, megabyte, terabyte and exabyte.

This was last updated in March 2015

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